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A qualitative assay for beta cell antibodies. Preliminary results in dogs with diabetes mellitus
Abstract
Purified beta cells from a radiation-induced transplantable rat insulinoma were used to detect beta cell antibodies in serum from untreated diabetic dogs. Serum from dogs in which anti-beta cell antibodies were induced by injecting a purified beta cell suspension subcutaneously was used as positive control. Following incubation with test sera, fluorescein-labeled anti-dog immunoglobulins were used to visualize binding between the beta cells and dog gamma globulins. Nine of the 23 diabetic dogs showed a strongly positive reaction which was characterized by a ring fluorescence, three showed a weak reaction and 11 were negative, i.e. they showed diffuse fluorescence. In contrast, 14 of the 15 healthy dogs showed diffuse fluorescence and one dog showed a weakly positive reaction. Thyroid, liver and kidney cells did not elicit ring fluorescence. Although females (spayed and intact) represented the majority of the diabetic dogs, there was no correlation between sex and the occurrence of antibodies in the diabetic dogs. There was also no correlation to the age of the dogs. In conclusion, we have developed a specific test for anti-beta cell antibodies. The test is reproducible and economical to perform on a large number of samples.
... Diabetes mellitus, hypoadrenocorticism, hypothyroidism, and hypoparathyroidism may result from an underlying immune-mediated etiology in dogs. 7,[21][22][23][24][25] It is possible that the dogs in the present study with combinations of those endocrine diseases were affected by a common immune-mediated etiology in the development of their multiple endocrinopathies, similar to humans affected by polyendocrinopathy syndromes. Only 2 dogs with hypothyroidism in the present study had thyroglobulin autoantibodies measured: 1 was seropositive for thyroglobulin autoantibodies, and 1 was seronegative for thyroglobulin autoantibodies. ...
... Diabetes mellitus in dogs is considered to develop at least partially from immune-mediated pancreatic destruction, whereas hyperadrenocorticism in the dogs of the present study was thought to develop from a pituitary adenoma. 7,23,24 In the present report, most of the dogs with concurrent diabetes mellitus and hyperadrenocorticism had diabetes mellitus as their first endocrine disorder. The diagnosis of diabetes mellitus preceded the diagnosis of hyperadrenocorticism by a mean of 12.6 months (median, 4 months; range, 12 days to 49 months). ...
To characterize a population of dogs from a tertiary care center with 2 or more endocrine disorders, including the specific disorders and time intervals between diagnosis of each disorder.
Retrospective case series.
35 dogs with 2 or more endocrine disorders.
Medical records were reviewed, and the following was recorded: clinical signs, physical examination findings, and the results of CBC, serum biochemical analysis, urinalysis, aerobic bacterial culture of urine samples, endocrine testing, diagnostic imaging, and necropsy.
35 dogs with more than 1 endocrine disorder were identified. Seventy-seven percent (27/35) of the dogs were male, and the mean age at the time of diagnosis of the first endocrinopathy was 7.9 years. Miniature Schnauzer was the most common breed. Twenty-eight of 35 (80%) dogs had 2 disorders; 7 (20%) had 3 disorders. The most common combinations of disorders included diabetes mellitus and hyperadrenocorticism in 57.1 % (20/35) of dogs; hypoadrenocorticism and hypothyroidism in 22.9% (8/35) of dogs; and diabetes mellitus and hypothyroidism in 28.6% (10/35) of dogs. A mean of 14.5 months elapsed between diagnosis of the first and second endocrine disorders, whereas there was a mean of 31.1 months between diagnosis of the first and third endocrine disorders.
Results suggested that the occurrence of multiple endocrine disorders was uncommon in dogs. The most common combinations of endocrine disorders in this population of dogs were diabetes mellitus and hyperadrenocorticism, followed by hypoadrenocorticism and hypothyroidism.
... In dogs, IDDM resembles type 1A DM (T1ADM) diagnosed in humans, where the body causes autoimmune destruction of the insulin-producing β-cells in the pancreas [6]. Evidence of a serological autoantibody reaction to pancreatic β-cell proteins has been reported in dogs as well [7][8][9][10]. In contrast to T1ADM in humans that mainly occur during childhood, the disease has a later onset in dogs, with a peak prevalence between 7 and 10 years [4,11]. ...
Background
Diabetes mellitus (DM) and hypothyroidism are common canine endocrinopathies. Both canine DM and primary hypothyroidism are assumed to originate from autoimmune destruction of the respective endocrine glands and have been associated with the major histocompatibility complex (MHC) gene region. This study aims to investigate breed distributions for DM and hypothyroidism in the Norwegian canine population by calculating odds ratios (OR) from two different comparator groups.
Methods
Results from canine serum samples submitted from 2001 to 2018 to the Veterinary Clinical Pathology Laboratory (VCPL) at the Faculty of Veterinary Medicine, Norwegian University of Life Sciences for analysis of fructosamine and thyroid hormones in serum were used as cases in a retrospective bivariate analysis of canine breeds. The ORs were calculated as a measure of risk for the included breeds, where all the submitted blood samples to the VCPL and dogs registered in the Norwegian Kennel Club (NKK), the national organization for dog owners, were used as two comparator groups.
Results
Significant differences in disease prevalence between breeds were discovered using both comparator groups. Australian terrier, Swedish lapphund, Samoyed, and Schipperke were at highest risk for DM. German Shepherd, Golden retriever, German pointing dog, and Collie presented as the breeds with lowest risk for DM. For hypothyroidism, Schnauzer, Eurasier, Dunker, and English setter were at highest risk for developing the disease. The breeds at lowest risk of developing hypothyroidism were Rottweiler, Dachshund, German shepherd, and Border collie. The results from the different comparator groups gave different ORs and ranks, but the breeds with highest and lowest odds showed the same susceptibility using both comparators.
Conclusions
These findings support that there are breeds more and less prone to develop DM and hypothyroidism. A strong genetic predisposition involved in the aetiology of these two diseases is therefore likely. Interestingly, there also appeared to be an inverse relationship of odds for the two diseases for some of the breeds since some breeds that had a high OR for DM or hypothyroidism had a lower OR for the other disease. This indicates that there may be different risk alleles/haplotypes for the two diseases. The possible aetiological relationship between canine DM and hypothyroidism should be further investigated.
... Even though IDD resembles many of the hallmarks of human type 1 diabetes (T1D), the underlying cause of pancreatic b-cell destruction is less clear than in T1D, in which an immune-mediated pathogenesis is well established (American Diabetes Association 2014). However, evidence for autoimmunity in the pathogenesis of canine diabetes is present in multiple studies, which detected serum anti-b-cell antibodies and insulin antibodies, as well as proinsulin autoantibodies, in untreated diabetic dogs (Hoenig & Dawe 1992;Davison et al. 2008aDavison et al. , 2008bDavison et al. , 2011Holder et al. 2015). Additionally, autoantibodies against GAD65 or IA-2, two major autoantigens in T1D, were found in newly diagnosed, untreated diabetic dogs (Davison et al. 2008a(Davison et al. , 2008b. ...
Insulin deficiency diabetes (IDD) in dogs is an endocrine disease similar to human type 1 diabetes. There are breeds more commonly affected, such as Yorkshire Terrier and Samoyed, suggesting an underlying genetic component. However, the genetic basis for canine diabetes mellitus (DM) is not fully established. We conducted both whole‐genome scans for selection signatures and GWASs to compare the genomes of 136 dogs belonging to 29 breeds previously described at low or high risk for developing DM. Candidate variants were tested in dogs with a diagnosis of IDD and controls attending the Complutense Veterinary Teaching Hospital. The only genomic region under selection (CFA8:72 700 000–74 600 000; CanFam3.1) retrieved by our analyses is included in the immunoglobulin heavy chain gene cluster, which has already been related to human human type 1 diabetes susceptibility. This region contains two non‐synonymous variants, rs852072969 and rs851728071, showing significant associations with high or low risk for IDD, respectively. The first variant, rs852072969, alters a protein poorly characterised in the dog. In contrast, rs851728071 was predicted to block the synthesis of an immunoglobulin variable (V) domain in breeds at low risk for DM. Although a large and diverse V gene repertoire is thought to offer a fitness advantage, we suggest that rs851728071 prevents the formation of an auto‐reactive immunoglobulin V domain probably involved in the pathophysiology of IDD and, thus, decreases the risk for the disease. These results should be interpreted with caution until the functional roles of the proposed variants have been proved in larger studies.
... La preuve de l'existence de ce type de diabète repose tout d'abord sur la description d'une insulite chez quelques chiens et chats diabétiques (Gepts et Toussaint, 1967 ;Minkus et al, 1991 ;! Saï, 1985). La présence d'ICA chez certains chiens diabétiques a été suggérée à plusieurs reprises (Haines et Peiihale, 1985 ;Henig et Dawe, 1992) même si certains anticorps initialement pris pour des ICA pourraient n'être que des anticorps anti-insuline. Plus encore, une immunité cellulaire anti-cellules a a été révélée chez certains chiens diabétiques insulinopéniques, grâce à un test in vitro d'agression des cellules f3 par des lymphocytes circulants (Saï et al, 1984). ...
... D iabetes mellitus is a common endocrinopathy in dogs, with reported prevalence ranging from 1 in 100 to 1 in 500 dogs affected. 1 The cause of DM in dogs is multifactorial, and studies [2][3][4][5] suggest that genetics, environmental factors, and immune-mediated components contribute to the development of the disease. Epidemiological studies 1,4,6 show that age of onset for most affected dogs is between 4 and 15 years and that female dogs have an increased risk of developing DM. ...
Objective:
To evaluate and compare regulation of diabetes mellitus (DM) in dogs with cataracts and well-controlled DM that received an ophthalmic preparation of prednisolone acetate versus diclofenac sodium.
Animals:
22 client-owned dogs with cataracts and well-controlled DM.
Procedures:
A prospective, randomized, double-masked, experimental study was conducted. On days 0 and 32, serum fructosamine concentrations (SFCs), clinical scores, and body weights were determined. Dogs were assigned to receive a topically administered ophthalmic preparation of either prednisolone acetate 1% or diclofenac sodium 0.1% in each eye 4 times daily for 28 days. Data analysis was conducted with generalized linear mixed models.
Results:
Findings indicated no meaningful differences in SFCs, clinical scores, or body weights between the treatment groups on days 0 or 32. Clinical score on day 0 was positively associated with SFC, as indicated by the corresponding rate of change such that each 1 -unit increase in clinical score was associated with an approximately 45.6 ± 9.4 μmol/L increase in SFC. In addition, the least squares mean ± SEM SFC was higher in spayed females (539.20 ± 19.23 μmol/L; n = 12) than in castrated males (458.83 ± 23.70 μmol/L; 8) but did not substantially differ between sexually intact males (446.27 ± 49.72 μmol/L; 2) and spayed females or castrated males regardless of the treatment group assigned.
Conclusions and clinical relevance:
Findings indicated no evidence for any differential effect on DM regulation (assessed on the basis of SFCs, clinical scores, and body weights) in dogs treated topically with an ophthalmic preparation of prednisolone versus an ophthalmic preparation of diclofenac. Additional research investigating plasma concentrations of topically applied ophthalmic glucocorticoid medications is warranted. (Am J Vet Res 2019;80:1129-1135).
... Ο τύπου Ι πρωτογενής ΣΔ χαρακτηρίζεται από τη μη αντι στρεπτή καταστροφή των β-κυττάρων των νησιδίων του Langerhans, που δεν μποροΰν πλέον να παράγουν την απαιτουμένη ποσότητα ινσουλίνης για τη διατήρηση της μεταβολικής ομοιοστασίας του οργανισμοΰ. Στον άνθρω πο και το σκΰλο τα περισσότερα περιστατικά της επίκτη της μορφής του τΰπου Ι ΣΔ οφείλονται σε καταστροφή των β-κυττάρων μέσω ανοσολογικών μηχανισμών (αυτοάνοση νησίϊτιδα) (Eisenbarth 1986, Alejandro et al. 1988, Hoening and Dawe 1992, Atkinson and Maclaren 1994, Feldman and Nelson 2004a. Αντίθετα, στη γάτα η αιτιο λογία του παραμένει σε σημαντικό βαθμό αδιευκρίνιστη, αφοΰ στην ιστοπαθολογική εξέταση του παγκρέατος σπά νια διαπιστώνεται φλεγμονώδης διήθηση που να αφορά αποκλειστικά και μόνο στα νησίδια του Langerhans, ενώ από τον ορό του αίματος συνήθως απουσιάζουν τα κατά της ινσουλίνης ή/και των β-κυττάρων αυτοαντισώματα (Hoening et al. 2000). ...
Diabetes mellitus, the clinical syndrome that results form absolute or relative insulin deficiency and/or reduced number or sensitivity of the insulin receptors, is considered one of the most common endocrine diseases in the cat, being secondary only to hypethyroidism. The exact etiology of type I feline diabetes mellitus remains obscure, although in many cases occurs secondarily to chronic pancreatitis. Type II diabetes mellitus, which is very common in the everyday clinical practice, is characterized by relative insulin deficiency, secondary to reduced production of this hormone (chronic pancreatitis, pancreatic amyloidosis), insulin resistance and/or increased glucose production by the liver (obesity, chronic stress, overproduction of amylin). Secondary (type III) diabetes mellitus is the result of various causes, not directly involving pancreatic tissue, that cause insulin resistance, such as hyperadrenocorticism, pheochromocytoma, acromegaly, hyperthyroidism, infections, neoplasia, hyperlipidemia, chronic heart and renal failure and the exogenous administration of glucocorticoids and progestagens. The most common clinical manifestations of feline non-ketotic diabetes mellitus include polyuria, polydipsia, polyphagia, weight loss, hepatomegaly, retinopathy, peripheral polyneuropathy, dry seborrhea and those resulting form the secondary infections, such as cystitis and stomatitis.
... In untreated diabetic dogs, circulating islet cell autoantibodies (ICA) were not detected using either frozen human or canine pancreas (37). Using purified islets from rat insulinoma as an antigen, approximately 12 of 23 (52%) untreated diabetic dogs demonstrated serum anti-b-cell antibodies detected via immunofluorescence (62). This may be analogous to humans who are positive for ICA yet negative for the other autoantibodies (63). ...
Despite decades of research in humans and mousemodels of disease, substantial gaps remain in our understanding of pathogenic mechanisms underlying the development of type 1 diabetes. Furthermore, translation of therapies from preclinical efforts capable of delaying or halting β-cell destruction has been limited. Hence, a pressing need exists to identify alternative animal models that reflect human disease. Canine insulin deficiency diabetes is, in some cases, considered to follow autoimmune pathogenesis, similar to NOD mice and humans, characterized by hyperglycemia requiring lifelong exogenous insulin therapy. Also similar to human type 1 diabetes, the canonical canine disorder appears to be increasing in prevalence. Whereas islet architecture in rodents is distinctly different from humans, canine pancreatic endocrine cell distribution is more similar. Differences in breed susceptibility alongside associations with MHC and other canine immune response genes parallel that of different ethnic groups within the human population, a potential benefit over NOD mice. The impact of environment on disease development also favors canine over rodent models. Herein, we consider the potential for canine diabetes to provide valuable insights for human type 1 diabetes in terms of pancreatic histopathology, impairment of β-cell function and mass, islet inflammation (i.e., insulitis), and autoantibodies specific for β-cell antigens.
... There is evidence of cell-mediated autoimmune destruction of b-cells in up to 50% of diabetic dogs [26][27][28][29][30] in some studies whereas others have found no evidence of autoimmune destruction. [31][32][33][34][35] In a study evaluating serum from 48 dogs with recently diagnosed but untreated DM, autoantibodies reactive against the cytoplasmic content of normal canine islet cells were not detectable in any sample. ...
Diabetes Mellitus (DM) is a syndrome caused by various etiologies. The clinical manifestations of DM are not indicative of the cause of the disease, but might be indicative of the stage and severity of the disease process. Accurately diagnosing and classifying diabetic dogs and cats by the underlying disease process is essential for current and future studies on early detection, prevention, and treatment of underlying disease. Here, we review the current etiology-based classification of DM and definitions of DM types in human medicine and discuss key points on the pathogenesis of each DM type and prediabetes. We then review current evidence for application of this etiology-based classification scheme in dogs and cats. In dogs, we emphasize the lack of consistent evidence for autoimmune DM (Type 1) and the possible importance of other DM types such as DM associated with exocrine pancreatic disease. While most dogs are first examined because of DM in an insulin-dependent state, early and accurate diagnosis of the underlying disease process could change the long-term outcome and allow some degree of insulin independence. In cats, we review the appropriateness of using the umbrella term of Type 2 DM and differentiating it from DM secondary to other endocrine disease like hypersomatotropism. This differentiation could have crucial implications on treatment and prognosis. We also discuss the challenges in defining and diagnosing prediabetes in cats.
... Immune-mediated insulitis may play a role in development of IDDM in dogs because beta-cell-specific antibodies have been identified in approximately 50% of diabetic dogs studied. 5 Non-insulin-dependent DM is classically characterized by insulin resistance in peripheral tissues and/or dysfunctional beta cells. 6 NIDDM is less common in dogs than in cats and not well described but still accounts for approximately one in five cases of diabetes. ...
The goals of nutritional therapy in the management of diabetes mellitus are to approach physiologic blood glucose levels, match postprandial glucose absorption with insulin therapy, attain and maintain optimal body weight, reduce the likelihood of diabetic complications, and address other concurrent disease conditions amenable to dietary therapy. Managing diabetes mellitus requires a consistent feeding plan and food that minimizes postprandial fluctuations in blood glucose concentrations. Because fiber modulates blood glucose levels and favors optimum body weight maintenance, the single most effective dietary tool in the medical management of diabetic dogs is feeding a diet containing insoluble or soluble fiber at 8% to 18% on a dry-matter basis.
... Although autoimmunity has been often cited as a possible mechanism underlying β-cell loss in canine diabetes, direct evidence supporting this hypothesis is sparse. About half of new onset cases in one study had anti-insulin antibodies [44]. Antibodies against the self-antigens Gad65 and IA2 were detected in a minority (5 of 30) of dogs with newly diagnosed diabetes [13]. ...
The pathophysiology of canine diabetes remains poorly understood, in part due to enigmatic clinical features and the lack of detailed histopathology studies. Canine diabetes, similar to human type 1 diabetes, is frequently associated with diabetic ketoacidosis at onset or after insulin omission. However, notable differences exist. Whereas human type 1 diabetes often occurs in children, canine diabetes is typically described in middle age to elderly dogs. Many competing theories have been proposed regarding the underlying cause of canine diabetes, from pancreatic atrophy to chronic pancreatitis to autoimmune mediated β-cell destruction. It remains unclear to what extent β-cell loss contributes to canine diabetes, as precise quantifications of islet morphometry have not been performed. We used high-throughput microscopy and automated image processing to characterize islet histology in a large collection of pancreata of diabetic dogs. Diabetic pancreata displayed a profound reduction in β-cells and islet endocrine cells. Unlike humans, canine non-diabetic islets are largely comprised of β-cells. Very few β-cells remained in islets of diabetic dogs, even in pancreata from new onset cases. Similarly, total islet endocrine cell number was sharply reduced in diabetic dogs. No compensatory proliferation or lymphocyte infiltration was detected. The majority of pancreata had no evidence of pancreatitis. Thus, canine diabetes is associated with extreme β-cell deficiency in both new and longstanding disease. The β-cell predominant composition of canine islets and the near-total absence of β-cells in new onset elderly diabetic dogs strongly implies that similar to human type 1 diabetes, β-cell loss underlies the pathophysiology of canine diabetes.
... Nos canídeos, existem estudos que demonstram que, em aproximadamente 50% dos casos, a doença resulta de um processo imuno-mediado semelhante ao que ocorre em humanos, tendo sido já identificados alguns anticorpos contra constituintes dos ilhéus de Langerhans (Hoening & Dawe, 1992), incluindo auto-anticorpos contra a isoforma canina 65 KDa da descarboxilase do ácido glutâmico (GAD65) e auto-anticorpos contra o antigénio-2 associado ao insulinoma (IA-2) (Catchpole, Ristic, Fleeman & Davison, 2005;Davison et al., 2003;Davison, Weenink, Herrtage, Christie & Catchpole, 2008; Hess, Kass & Ward, 2000a;Kimmel, Ward, Henthorn & Hess, 2002;Short et al., 2007). ...
... In contrast, half of diabetic dogs have type 1 diabetes and express antibodies against islet β cells [15,31]. Overrepresented dog leukocyte antigen gene influences the type 1 diabetes expression, especially on Samoyed dogs and Miniature Poodles [16,31]. Companion animals eat energy-dense diets that induce obesity-related hyperglycemia and impaired glucose tolerance which in turn increase the risk of infection [21,31,37]. ...
The incidence of diabetes mellitus is increasing among companion animals. This disease has similar characteristics in both humans and animals. Diabetes is frequently identified as an independent risk factor for infections associated with increased mortality. In the present study, homozygous diabetic (db/db) mice were infected with Listeria (L.) monocytogenes and then treated with the anti-diabetic drug exendin-4, a glucagon-like peptide 1 analogue. In aged db/db mice, decreased CD11b+ macrophage populations with higher lipid content and lower phagocytic activity were observed. Exendin-4 lowered high lipid levels and enhanced phagocytosis in macrophages from db/db mice infected with L. monocytogenes. Exendin-4 also ameliorated obesity and hyperglycemia, and improved ex vivo bacteria clearance by macrophages in the animals. Liver histology examined during L. monocytogenes infection indicated that abscess formation was much milder in exendin-4-treated db/db mice than in the control animals. Moreover, mechanistic studies demonstrated that expression of ATP binding cassette transporter 1, a sterol transporter, was higher in macrophages isolated from the exendin-4-treated db/db mice. Overall, our results suggest that exendin-4 decreases the risk of infection in diabetic animals by modifying the interaction between intracellular lipids and phagocytic macrophages.
... The occurrence of autoantibodies is a central characteristic of human T1D, and islet cell antibodies (ICA) and GAD65 autoantibodies are valuable diagnostic markers. The presence of autoantibodies in canine diabetes mellitus remains controversial, since both presence and absence of autoantibodies have been reported [5,[9][10][11][12]. Insulitis is commonly reported in samples from recent onset human T1D subjects [13]. ...
Aims/Hypothesis
Diabetes mellitus is one of the most common endocrine disorders in dogs and is commonly proposed to be of autoimmune origin. Although the clinical presentation of human type 1 diabetes (T1D) and canine diabetes are similar, the aetiologies may differ. The aim of this study was to investigate if autoimmune aetiology resembling human T1D is as prevalent in dogs as previously reported.
Methods
Sera from 121 diabetic dogs representing 40 different breeds were tested for islet cell antibodies (ICA) and GAD65 autoantibodies (GADA) and compared with sera from 133 healthy dogs. ICA was detected by indirect immunofluorescence using both canine and human frozen sections. GADA was detected by in vitro transcription and translation (ITT) of human and canine GAD65, followed by immune precipitation. Sections of pancreata from five diabetic dogs and two control dogs were examined histopathologically including immunostaining for insulin, glucagon, somatostatin and pancreas polypeptide.
Results
None of the canine sera analysed tested positive for ICA on sections of frozen canine or human ICA pancreas. However, serum from one diabetic dog was weakly positive in the canine GADA assay and serum from one healthy dog was weakly positive in the human GADA assay. Histopathology showed marked degenerative changes in endocrine islets, including vacuolisation and variable loss of immune-staining for insulin. No sign of inflammation was noted.
Conclusions/Interpretations
Contrary to previous observations, based on results from tests for humoral autoreactivity towards islet proteins using four different assays, and histopathological examinations, we do not find any support for an islet autoimmune aetiology in canine diabetes mellitus.
... The majority of diabetic dogs appear to have a form of type 1 diabetes analogous to the latent auto-immune diabetes of adults (LADA) in humans ( Fleeman and Rand 2001). At least 50% of diabetic dogs would be classified as type 1, because this proportion has been shown to have antibodies against beta cells (Hoenig and Dawe 1992, Elie and Hoenig 1995, Davison et al., 2003) The remainder probably has 'other specific types of diabetes' resulting from pancreatic destruction or chronic insulin resistance, or they have diestrus-induced diabetes (Rand et al., 2004). The prevalence of diabetes in dogs has been estimated to be 0.32% in the UK (Catchpole et al., 2005). ...
A study was conducted on the dogs with moderate to serious illness coming for treatment
at the Dog Ward of West Bengal University of Animal and Fishery Sciences, West Bengal, India, to
find out possible correlation between fasting blood sugar level with breed, sex and age of dogs. The
study result implicated that the blood sugar level was not having any general tendency to increase
with advancement of age of ailing dogs. The blood sugar level of ailing dogs was higher in small
breeds of dogs, particularly in 0 to <4 year age group. The large breeds showed highest level of sugar
in blood in disease condition at above the age 12 years or more. The blood sugar level of ailing dogs
had a gender bias, as it was found more in females than males in all breeds and age groups.
... Studies suggest an immune-mediated component in the development of diabetes in some dogs. Immunemediated insulitis characterized by infiltration of lymphocytes into the islets has been described and antibodies directed against islet cells, insulin, proinsulin, intracellular glutamic acid decarboxylase 65 (GAD65), and insulinoma antigen 2 (IA2) have been identified in diabetic dogs (Hoenig & Dawe 1992, Davison et al. 2003. The presence of circulating autoantibodies against insulin, proinsulin, GAD65, and IA2 usually precedes the development of hyperglycemia or clinical signs in humans with type 1 diabetes. ...
Diabetes mellitus is a common disease in dogs and cats. Diabetes in dogs resembles type 1 diabetes in humans. Studies suggest that genetics, an immune-mediated component, and environmental factors are involved in the development of diabetes in dogs. A variant of gestational diabetes also occurs in dogs. The most common form of diabetes in cats resembles type 2 diabetes in humans. An important risk factor in cats is obesity. Obese cats have altered expression of several insulin signaling genes and glucose transporters and are leptin-resistant. Cats also form amyloid deposits within the islets of the pancreas and develop glucotoxicity when exposed to prolonged hyperglycemia . This review will briefly summarize our current knowledge of the etiology of diabetes in dogs and cats and illustrate the similarities between dogs, cats and humans.
... Diabetes mellitus type 2 (DMT2) is a common endocrine disorders in men and, among domestic animals, cats are most frequently affected (Nelson et al., 1990;Panciera et al., 1990;Kahn, 2001, Rand et al., 2004Appleton et al., 2005). In dogs, a form resembling human type 1 diabetes accompanied with autoimmune destruction of pancreatic β-cells is predominantly seen (Lendrum et al., 1976;Baekkeskov et al., 1982;Palmer et al., 1983;Hoenig & Dawe, 1992;Hoenig, 2002). ...
... In canine DM, the evidence for autoimmunity is less convincing than that in humans and rodents, although only a small number of studies have been undertaken. Insulitis, as demonstrated by histopathology , is not a consistent feature of canine DM (Alejandro et al., 1988 ), although anti-islet antibody reactivity has been demonstrated by immunofluorescence in a proportion of serum samples from canine diabetic patients (Hoenig and Dawe 1992). Another study suggested that canine diabetic sera contain antibodies capable of stimulating complement-mediated beta cell lysis (Sai et al., 1984 ). ...
To determine whether dogs with spontaneously-occurring diabetes mellitus demonstrate serological reactivity to proinsulin.
Serum samples were collected from 15 newly-diagnosed diabetic, 15 insulin-treated diabetic and 15 non-diabetic control dogs.
Canine proinsulin was cloned into a prokaryotic expression vector to generate recombinant poly-histidine-tagged protein in Escherichia coli. A Western blotting assay was developed for detection of proinsulin autoantibodies in canine sera.
Reactivity to canine proinsulin was detected in 3 of 15 control dogs, 8 of 15 newly-diagnosed diabetic dogs and 6 of 15 insulin-treated diabetic patients. Of these reactors, only 1 control dog, 1 newly-diagnosed diabetic dog and 3 insulin-treated diabetic dogs recognised porcine insulin by ELISA, suggesting that the remaining proinsulin reactors might have been recognising proinsulin-specific epitopes.
This study suggests that proinsulin autoantibodies are present in a proportion of diabetic dogs. Further work is required to refine the assay and clarify the significance of these autoantibodies.
... For allocation to the class immune-mediated diabetes in dogs, the diagnostic criteria and tools need to be refined. Hoenig and Dawe (1992) found nonspecific anti-islet reactivity in nine out of 23 dogs of various breeds newly diagnosed with diabetes. Davison et al (2008) found increased gad65 and IA-2 antibody reactivity in five out of 30 newly diagnosed dogs compared to controls. The increases were much smaller than what is seen in human type 1 diabetes. The auto-antibody ...
Diabetes mellitus is considered a common endocrine disorder in dogs. The underlying pathology is, however, poorly understood. Epidemiological, genetic and clinical research, as well as the clinical management of diabetic dogs, requires an appropriate system of classification that provides a framework within which various forms and stages of diabetes mellitus can be identified and differentiated. The overall aim of this doctoral research was to further characterise the different subtypes of canine diabetes mellitus.
In the first study, a population-based epidemiological study, breed- gender- and age-specific incidence rates were calculated, and survival after diagnosis was estimated. A major finding was that in some breeds such as elkhounds and border collies, only female dogs were affected by diabetes.
In the second study, beta cell function was assessed in dogs through measurement of C-peptide before and after an intravenous injection of glucagon. Healthy dogs showed a marked increase in the serum concentration of C-peptide after glucagon stimulation, indicating that the test is suitable for the purpose. In most diabetic dogs, C-peptide did not increase after glucagon stimulation, indicating beta cell dysfunction. The test has a potential use for subtyping diabetes mellitus in newly diagnosed dogs.
A specific subtype of diabetes, gestational diabetes mellitus, was clinically characterised in the third study. Gestational diabetes mellitus is rare in dogs, and the case series in this study is the largest one described to date.
In the fourth study, diabetes mellitus was investigated in 63 Swedish and Norwegian elkhounds. From the latter two studies it was concluded that those elkhound breeds are predisposed to progesterone-related forms of diabetes mellitus (diœstrous and gestational diabetes mellitus), which have several characteristics in common with human gestational diabetes mellitus and may serve as a novel animal model for that disease.
A new classification system for canine diabetes mellitus is proposed based on the basis of earlier studies and the newly gained knowledge. The following classes are proposed: juvenile; progesterone-related; secondary to pancreatic insult; endocrine tumours; iatrogenic; immune-mediated; and idiopathic.
... Orsakerna till förlusten av betaceller hos hund är inte helt utredda men en rad sjukdomsprocesser tros ligga bakom. Immunmedierad destruktion av betaceller räknas som en av orsakerna (Catchpole, 2005, Davison, 2008, Hoenig, 1992). Det har också beskrivits att hundar med DM även samtidigt kan lida av akut pankreatit (Cook, 1985-1990, Fleeman, 2001) eller exokrin pankreasinsufficiens (Catchpole, 2005) och detta anses bero på (i alla fall avseende pankreatit) att inflammation i exokrina pankreas även kan leda till att den endokrina delen påverkas av de inflammatoriska mediatorerna. ...
Diabetes mellitus (DM) is a relatively common endocrine disease in dogs and is more common in certain breeds than others, e.g. Nordic spitz breeds. Within the Swedish and Norwegian Elkhound population, female dogs are almost exclusively affected. The hypothesis in this study is that Swedish- and Norwegian Elkhounds develop DM during the progesterone phase of estrous (diestrous or pregnancy).
Medical records from 51 female dogs of the breeds Swedish and Norwegian Elkhound were studied. All cases derived from the Canine Diabetes Mellitus Project at the University of Agricultural Sciences (SLU) up to July 2008. The dogs were followed in average 2,8 months (range one day to 37 months). The study shows that the dogs develop DM in progesterone phase (diestrous or pregnancy). The study also showed that in several cases, remission of the disease was obtained after ovariohysterectomi of the dogs. Moreover, it was indicated that the best chance for remission was if the time lap from the start of clinical signs until performance of the ovariohysterectomi became as short as possible. Thus, the recommendation is to perform an ovariohysterectomi as soon as possible after confirmation of the diagnosis.
Insulin and progesterone concentrations were measured in 15 female dogs with DM and 15 healthy female dogs. The study showed no significant difference in either insulin or progesterone concentrations between sick and healthy female dogs. However, the study showed that most of the female dogs with DM still had insulin production at the time of diagnosis. The insulin concentrations in dogs with DM showed a tendency to be higher at the beginning of the progesterone phase. Further studies with increased number of dogs would be of interest in order to further evaluate differences in both insulin and progesterone concentrations in female elkhounds.
... In a previous study evaluating anti-islet autoreactivity in the sera of newly diagnosed canine diabetic patients, 12 of 23 dogs were found to be positive for islet cell autoantibodies by immmunofluoresence. 19 The larger proportion of cases with autoreactivity compared with the present study might relate to differences in sensitivity of the techniques used, but it is also possible that autoantibody recognition of other islet autoantigens apart from insulin led to islet immunofluoresence. Such antigens might include glutamic acid decarboxylase 65 or insulinoma antigen-2, which are important in human type 1 diabetes, with preliminary veterinary studies also suggesting a potential role in the disease in dogs. ...
Anti-insulin antibodies (AIA) occur in diabetic dogs after insulin therapy, although their clinical significance is unclear.
Treatment of diabetic dogs with heterologous insulin is more likely to stimulate production of AIA than is treatment with homologous insulin.
Diabetic dogs sampled before insulin therapy (n = 40), diabetic dogs sampled following treatment with porcine (homologous) insulin (n = 100), bovine (heterologous) lente insulin (n = 100), or bovine protamine zinc (PZI) insulin (n = 20), and nondiabetic control dogs (n = 120).
Prospective observational study. Sera were analyzed by ELISA for antibodies against porcine insulin, bovine insulin, insulin A, B, or C peptides, and control antigens; canine distemper virus (CDV) and canine thyroglobulin (TG). Canine isotype-specific antibodies were used to determine total and anti-insulin IgG1 : IgG2 ratios.
There was no difference in CDV or TG reactivity among the groups. AIA were detected in 5 of 40 newly diagnosed (untreated) diabetic dogs. There was no significant difference in AIA (ELISA optical density reactivity) comparing control and porcine insulin-treated diabetic dogs (P > .05). Anti-insulin reactivity was most prevalent in bovine PZI insulin-treated dogs (90%; P < .01), and bovine lente insulin-treated dogs (56%; P < .01). AIA induced by treatment were enriched for the IgG1 isotype.
This study indicates that bovine insulin is more immunogenic than porcine insulin when used for treatment of diabetic dogs.
... Diabetes due to insulin deficiency is considered to be caused by the autoimmune destruction of insulin-producing β-cells, pancreatitis or islet hypoplasia (Kramer 1981, Hoenig and Dawe 1992, Cook and others 1993. Insulin-resistant diabetes may occur as a result of hormonal disturbances; for example, hyperadrenocorticism and progesterone-induced acromegaly (Eigenmann andothers 1983, Peterson andothers 1984). ...
Fifty-one dogs (27 diabetic dogs, four that had recovered from diabetes and 20 healthy control dogs) were given 0.5 or 1.0 mg glucagon intravenously. Blood samples were taken before the injection and 10 and 20 minutes after it. Samples were analysed to determine C-peptide, insulin and glucose concentrations, and one sample from each dog was analysed for fructosamine. The median (interquartile range) concentrations of C-peptide in the samples taken at 10 minutes were 0.5 (0.3 to 0.8) nmol/l in the control dogs, 0.1 (0 to 0.2) nmol/l in the diabetic dogs, and 0.3 (0.2 to 0.4) nmol/l in the dogs that had recovered from diabetes. Seven of the 51 dogs showed mild adverse reactions after the injection of glucagon.
Autoimmunity defines a state in which the natural immunologic tolerance or unresponsiveness to self-antigen terminates. As a result, immune responses against the self- antigens induce pathology, known as autoimmune diseases. These are now considered a major medical problem of today’s industrialized societies. With the major advances in veterinary immunology, autoimmune disorders are being identified in animals and birds too. The term autoimmunity was first introduced by Paul Ehrlich to convey immunity against self. Autoimmunization needs all the components and mechanism of the immune system but to cause self-destruction in the host, it requires to overcome all those mechanisms that prevents the harmful effects of the autoimmunity. In autoimmunity, problem does not lie in autoantibodies or T-cells that cause the lesions in the disease but lie in the complex network of components that stimulate the event. The complexity of the problem was further compounded by the fact that autoimmunity is an inherent property of the normal immune system. Therefore, despite the major development in the field of immunology, a unifying concept to explain the origin and pathogenesis of various autoimmune disorders is yet to the established. Experimental evidences are, however, accumulating in favour of the opinion that autoimmune disease may result from a wide variety of genetic, environmental, and immunological factors. Classical examples of systemic autoimmune diseases are systemic lupus erythematosus (SLE), rheumatoid arthritis, canine dermatomyositis, Sjogren’s syndrome, and vasculitides.
Background: Diabetes mellitus (DM) and hypothyroidism are common canine endocrinopathies. Both primary (“Type 1”) DM and primary hypothyroidism are assumed to originate from autoimmune destruction of the respective endocrine glands and have been associated with the major histocompatibility complex (MHC) gene region. This study aims to investigate canine breed distributions for DM and hypothyroidism and calculate odds ratios (OR) for both diseases in the included breeds.
Methods: Results from canine serum samples submitted from 2001-2018 to the Veterinary Clinical Pathology Laboratory (VCPL) at the Faculty of Veterinary Medicine, Norwegian University of Life Sciences for analysis of fructosamine and thyroid hormones in serum were used in a retrospective case-control study. OR was calculated as a measure of risk for the included breeds, where all the submitted blood samples to the VCPL and dogs registered in the Norwegian Kennel Club (NKK), the national organization for dog owners, were used as two alternative control populations.
Results: Significant differences in disease incidence between breeds were discovered. Australian terrier, Swedish lapphund, Samoyed, and Schipperke were at highest risk for DM. German Shepherd, Golden retriever, German pointing dog, and Collie presented as the breeds with lowest risk for DM. For hypothyroidism, Schnauzer, Eurasier, Dunker, and English setter were at highest risk for developing the disease. The breeds at lowest risk of developing hypothyroidism were Rottweiler, Dachshund, German shepherd, and Border collie.
Conclusions: These findings support that there is a strong genetic predisposition involved in the aetiology of these two diseases. Interestingly, there also appeared to be an inverse relationship of risk for the two diseases for some of the breeds since some breeds that had a high OR for DM or hypothyroidism have a lower OR for the other disease. This indicates that there may be different risk alleles/haplotypes for the two diseases. The possible etiological relationship between canine DM and hypothyroidism should be further investigated.
Canine diabetes has been considered a potential model of human type 1 diabetes (T1D), however the detection of autoantibodies common in humans with T1D in affected dogs is inconsistent. The aim of this study was to compare autoantibody responses in diabetic and healthy control dogs using a novel nucleic acid programmable protein array (NAPPA) platform. We performed a cross-sectional study of autoantibody profiles of 30 diabetic and 30 healthy control dogs of various breeds. Seventeen hundred human proteins related to the pancreas or diabetes were displayed on NAPPA arrays and interrogated with canine sera. The median normalized intensity (MNI) for each protein was calculated, and results were compared between groups to identify candidate autoantibodies. At a specificity of 90%, six autoantibodies had sensitivity greater than 10% (range 13–20%) for distinguishing diabetic and control groups. A combination of three antibodies (anti-KANK2, anti-GLI1, anti-SUMO2) resulted in a sensitivity of 37% (95% confidence interval (CI) 0.17–0.67%) at 90% specificity and an area under the receiver operating characteristics curve of 0.66 (95% CI 0.52–0.80). While this study does not provide conclusive support for autoimmunity as an underlying cause of diabetes in dogs, future studies should consider the use of canine specific proteins in larger numbers of dogs of breeds at high risk for diabetes.
Obesity in pet dogs and cats is a significant problem in developed countries, and seems to be increasing in prevalence. Excess body fat has adverse metabolic consequences, including insulin resistance, altered adipokine secretion, changes in metabolic rate, abnormal lipid metabolism, and fat accumulation in visceral organs. Obese cats are predisposed to endocrine and metabolic disorders such as diabetes and hepatic lipidosis. A connection likely also exists between obesity and diabetes mellitus in dogs. No system has been developed to identify obese pets at greatest risk for development of obesity-associated metabolic diseases, and further study in this area is needed.
In both the dog and the cat the pancreas is a V-shaped organ. The angle points forward and lies caudomedial to the pylorus. The left lobe is somewhat shorter and thicker than the right lobe. Two pancreatic ducts discharge exocrine secretions into the duodenum (Fig. 5–1). Scatterred throughout the exocrine tissue there are numerous clusters of cells called islets of Langerhans (Fig. 5–2). In young animals the islets comprise about 5% of the volume of the pancreas and in adults 1–2%.
The objective of this study was to describe alterations in blood clinical biochemistry and urinalysis which enable to establish the diagnosis of diabetes mellitus in dogs. Thirty cases of diabetic dogs were analyzed. The inclusion criteria were the following: hyperglycemia above 14 mmol/L, glucosuria, urine density above 1.014 and polyuria-polydipsia. Dogs of different breeds, from 7 months to 14 years of age and both genders (73.3% females and 26.7% males) were studied. The most frequent biochemical alterations in blood serum were: hyperglycemia (100%), increased urea (46%) and creatinine (13%), increase of enzyme activities ALT (50%), AST (46%), alkaline phosphatase (56%), amylase (20%), creatine kinase (66%); hypercholesterolemia (66%), hyperglobulinemia (33%), hyperphosphoremia (33%), hyperkaliemia (43%), hyponatremia (16%), hypochloremia (46%), hypobicarbonatemia (50%), increased anion gap (53%), increased strong ion difference (30%), increased serum osmolality (23%) and hypertriglyceridemia (50%). The urine density was between 1.015 and 1.064, mean value of urine glucose 49 mmol/L. Urine ketone bodies were detected in 10% of all cases. Described alterations in clinical biochemistry are important for the diagnosis, clinical care, and prognosis of dogs with diabetes mellitus.
If you've diagnosed an endocrine gland disorder in one of your patients, you may be seeing only part of the picture. Be alert to clinical signs and clincopathologic findings that might suggest a concurrent endocrinopathy.
Diabetes mellitus (DM) is a common endocrine disease in dogs and cats, and whose incidence is increasing. The classification of DM in these species is oriented towards the human diabetes classification. In dogs, a type 1 DM is found, resulting from an autoimmune-mediated destruction of the beta cells of the pancreas. Feline DM is most commonly type 2, which is caused by insulin resistance, obesity and amyloid disposition in the pancreas. Another specific type of DM (type 3), caused by other diseases' or the use of drugs, is possible in both species. Regardless of the underlying aetiology, the hyperglycaemia is treated with exogenous insulin. Currently, porcine insulin and human recombinant insulin are used in veterinary medicine. Besides insulin, dietary management and good monitoring are necessary for successful treatment. Cats can go into remission. Insulin resistance can occur during the course of disease. Complications leading to insulin resistance can be technical problems, other underlying diseases (e. g. secondary endocrine disease, bacterial infection, pancreatitis, neoplasia) and diabetogenic drugs. In such cases, a comprehensive re-evaluation of the patient is needed, which can be challenging for the veterinarian.
Diabetes mellitus and pancreatitis are two distinct diseases encountered commonly in small animal practice. Whilst the clinical signs of diabetes mellitus are usually unmistakeable, a firm diagnosis of pancreatitis can prove more elusive, as clinical signs are often variable. Over the past 10 to 15 years, despite the fact that the clinical signs of diabetes mellitus are remarkably consistent, it has become more apparent that the underlying pathology of diabetes mellitus in dogs and cats is heterogeneous, with exocrine pancreatic inflammation accompanying diabetes mellitus in a number of cases. However, the question remains as to whether the diabetes mellitus causes the pancreatitis or whether, conversely, the pancreatitis leads to diabetes mellitus – as there is evidence to support both scenarios. The concurrence of diabetes mellitus and pancreatitis has clinical implications for case management as such cases may follow a more difficult clinical course, with their glycaemic control being “brittle” as a result of variation in the degree of pancreatic inflammation. Problems may also arise if abdominal pain or vomiting lead to anorexia. In addition, diabetic cases with pancreatitis are at risk of developing exocrine pancreatic insufficiency in the following months to years, which can complicate their management further.
Diabetes mellitus (DM) is a common disease in dogs and cats and its prevalence is increasing in both species, probably due to an increase in obesity, although only in cats has obesity been clearly identified as a major risk factor for diabetes. While the classification of diabetes in dogs and cats has been modeled after that of humans, many aspects are different. Autoimmune destruction of beta cells, a feature of type 1DM in people, is common in dogs; however, in contrast to what is seen in people, the disease occurs in older dogs. Diabetes also occurs in older cats but islet pathology in those species is characterized by the presence of amyloid, the hallmark of type 2DM. Despite being overweight or obese, most naive diabetic cats, contrary to type 2 diabetic humans, present with low insulin concentrations. The physiology of carbohydrate metabolism and pathogenesis of diabetes, including histopathologic findings, in dogs and cats are discussed in this chapter.
Serum glucose and plasma C-peptide response to IV glucagon administration was evaluated in 24 healthy dogs, 12 dogs with untreated diabetes mellitus, 30 dogs with insulin-treated diabetes mellitus, and 8 dogs with naturally acquired hyperadrenocorticism. Serum insulin response also was evaluated in all dogs, except 20 insulin-treated diabetic dogs. Blood samples for serum glucose, serum insulin, and plasma C-peptide determinations were collected immediately before and 5,10,20,30, and (for healthy dogs) 60 minutes after IV administration of 1 mg glucagon per dog. In healthy dogs, the patterns of glucagon-stimulated changes in plasma C-peptide and serum insulin concentrations were identical, with single peaks in plasma C-peptide and serum insulin concentrations observed approximately 15 minutes after IV glucagon administration. Mean plasma C-peptide and serum insulin concentrations in untreated diabetic dogs, and mean plasma C-peptide concentration in insulin-treated diabetic dogs did not increase significantly after IV glucagon administration. The validity of serum insulin concentration results was questionable in 10 insulin-treated diabetic dogs, possibly because of anti-insulin antibody interference with the insulin radioimmunoassay. Plasma C-peptide and serum insulin concentrations were significantly increased (P < .001) at all blood sarnplkg times after glucagon administration in dogs with hyperadrenocorticism, compared with healthy dogs, and untreated and insulin-treated diabetic dogs. Five-minute C-peptide increment, C-peptide peak response, total C-peptide secretion, and, for untreated diabetic dogs, insulin peak response and total insulin secretion were significantly lower (P < .001) in diabetic dogs, compared with healthy dogs, whereas these same parameters were significantly increased (P < .011 in dogs with hyperadrenocorticism, compared with healthy dogs, and untreated and insulin-treated diabetic dogs. Although not statistically significant, there was a trend for higher plasma C-peptide concentrations in untreated diabetic dogs compared with insulin-treated diabetic dogs during the glucagon stimulation test. Baseline C-peptide concentrations also were significantly higher (P < .05) in diabetic dogs treated with insulin for less than 6 months, compared with diabetic dogs treated for longer than 1 year. Finally, 7 of 42 diabetic dogs had baseline plasma C-peptide concentrations greater than 2 SD (ie, >0.29 pmol/mL) above the normal mean plasma C-peptide concentration; values that were significantly higher, compared with results in healthy dogs (P < .001) and with the other 35 diabetic dogs (P < .001). In summary, measurement of plasma C-peptide concentration during glucagon stimulation testing allowed differentiation among healthy dogs, dogs with impaired β-cell function (ie, diabetes mellitusl, and dogs with increased β-cell responsiveness to glucagon (ie, insulin resistance). Plasma C-peptide concentrations during glucagon stimulation testing were variable in diabetic dogs and may represent dogs with type-1 and type-2 diabetes or, more likely, differences in severity of β-cell loss in dogs with type-1 diabetes. J Vet Intern Med 1996;10:116–122. Copyright © 1996 by the American College of Veterinary Internal Medicine.
Measurement of canine serum insulin has relied on methods developed to measure human insulin. A species-optimized test for measurement of serum insulin in dogs is now commercially available.
The purpose of this study was to validate the canine ELISA for determination of serum insulin concentration in dogs.
Precision was determined by evaluating intra- and interassay coefficient of variation (CV), and accuracy was determined by dilution and spike recovery studies. A method comparison study with samples from 34 clinically healthy dogs and 73 dogs examined for various illnesses and disorders ("patients") was performed using the canine ELISA and an ELISA for human insulin. Biologic relevance of the canine assay was evaluated by measuring insulin in samples collected from 8 healthy dogs after administration of glucagon. A stability study was preformed with 6 samples stored at 20°C, 4-8°C, and -20°C.
For the canine ELISA, intra- and interassay CVs were 4.3-7.8% and 4.4-7.7%, respectively. Mean recovery after dilution was 99% and recovery after spiking with porcine insulin was 116%. The canine and human ELISAs correlated well (r(2) =.94 for healthy dogs, r(2) =.88 for patient samples). After glucagon injection serum insulin concentrations increased significantly in 8 dogs. Insulin was stable for 30 days in 6 serum samples stored at -20°C and in most samples for 8 days at 4-8°C. Insulin was stable for <3 days at room temperature (20°C).
The new canine serum insulin ELISA had good precision and accuracy and correlated well with the previously used assay.
Type 1 diabetes results from irreversible damage of insulin-producing ß-cells. In laboratory animals, diabetes can be induced with alloxan (ALX). ALX is a potent generator of reactive oxygen species (ROS), which can mediate ß-cell toxicity. However, the initial lesions on essential ß-cell structures are not known. In this study, we analyzed the effect of ALX on the glucose transporter 2 (GLUT2), glucokinase and proinsulin. For this purpose, we investigated the effect of pretreatment with the glucose analogues D-glucose (D-G) and 5-thio-D-glucose (5-T-G), as well as with zinc-enriched drinking water to induce the antioxidant metallothionein, on ALX-induced diabetes, on oral glucose tolerance (OGT) and on the mRNA-expression of the above mentioned genes with semiquantitative RT-PCR in male C57BL/6 and 129S3 mice. The total insulin content of ALX-treated pancreata was determined as immune reactive insulin. One single intravenous (iv) injection of 50 mg ALX/kg body weight (bwt) induced diabetes in 50% of mice of both strains (blood glucose level 11.1 mmol/l). One single iv preinjection of D-G prevented significantly (p0,001) diabetes in both strains, yet, in these euglycemic mice, an impaired oral glucose tolerance persisted. In contrast, the pretreatment with a single injection of 5-T-G potentiated significantly (p0,001) the toxicity of ALX. Administration of zinc-enriched drinking water, however, reduced ALX-induced hyperglycemia (p0,001). The mRNA-expression of GLUT2 and glucokinase was time-dependently reduced and the effect was more pronounced for GLUT2 (p0,001) than for glucokinase (p0,05). The pretreatment with D-G protected against the mRNA-reduction of both GLUT2 and glucokinase (p0,05). Interestingly, the mRNA-expression of proinsulin remained unaffected as well as the pancreatic total insulin content. A significant (p0,05) reduction of pancreatic insulin content was found after 24 h. In conclusion, ALX exerts differential toxicity on essential ß-cell structures. This toxic effect was more pronounced for GLUT2 than for glucokinase mRNA. Pretreatment with D-G prevented ALX-toxicity, whereas in euglycemic mice an impaired oral glucose tolerance persisted. It has to be elucidated, whether ALX-induced ROS select essential ß-cell structures or whether, as one possibility, transcription factors in the ß-cell are specifically directing ROS to GLUT2 and glucokinase mRNA. Finally, these results differ from those obtained with other diabetogens, e.g., streptozotocin, which exerts selective toxicity on the GLUT2 and which is prevented by 5-T-G. However, diabetogens damage ß-cell function through different pathogenic pathways and, therefore, different interventional regimen may be required to prevent type 1 diabetes in individuals at risk.
El objetivo de este estudio fue describir alteraciones en la bioquímica clínica sanguínea y en el urianálisis, con el fi n de establecer un diagnóstico integral en perros con diabetes mellitus. Se analizaron 30 casos de perros diabéticos. Los criterios de inclusión fueron: hiperglucemia superior a 14 mmol/L, glucosuria, densidad urinaria superior a 1.014 y poliuria-polidipsia. Los perros fueron de diferentes razas, de siete meses a 14 años de edad y de ambos géneros (73.3% hembras y 26.7% machos). Las frecuencias de las principales alteraciones bioquímicas en suero fueron: hiperglucemia (100.0%), incremento en las concentraciones de urea (46%) y de creatinina (13%), incremento de la actividad de las enzimas ALT (50%), AST (46%), fosfatasa alcalina (56%), amilasa (20%), creatina cinasa (66%), hipercolestrolemia (66%), hiperglobulinemia (33%), hiperfosforemia (33%), hipercaliemia (43%), hiponatremia (16%), hipocloremia (46%), hipobicarbonatemia (50%), aumento de ácidos no volátiles (53%), incremento en la diferencia de iones fuertes (30%), hiperosmolalidad (23%) e hipertrigliceridemia (50%). La densidad urinaria osciló entre 1.015 y 1.064, la glucosuria presentó, en promedio, 49 mmol/L. En 10% de los casos se observó cetonuria. Las alteraciones descritas en la bioquímica clínica son importantes para el diagnóstico, manejo clínico y pronóstico de los perros con diabetes mellitus.
A dog with immune-mediated haemolytic anaemia developed transient hyperglycaemia and glucosuria requiring insulin therapy in association with prednisone and cyclosporin A therapy. Following short-term therapy with insulin and cyclosporin A, the dog remained on prednisone therapy but required no further insulin therapy for 12 weeks, at which time the dog became permanently diabetic. We hypothesise that prednisone and cyclosporin A contributed to insulin resistance in a prediabetic dog with suboptimal endogenous insulin concentration and that the degree of insulin resistance decreased when cyclosporin A therapy was discontinued.
Insulin-deficiency diabetes in dogs shares some similarities with human latent autoimmune diabetes of adults (LADA). Canine diabetes is likely to have a complex pathogenesis with multiple genes contributing to overall susceptibility and/or disease progression. An association has previously been shown between canine diabetes and MHC class II genes, although other genes are also likely to contribute to the genetic risk. Potential diabetes susceptibility genes include immuno-regulatory TH1/TH2 cytokines such as IFNgamma, IL-12, IL-4 and IL-10. We screened these candidate genes for single nucleotide polymorphisms (SNPs) in a range of different dog breeds using dHPLC analysis and DNA sequencing. Thirty-eight of the SNPs were genotyped in crossbreed dogs and seven other breed groups (Labrador Retriever, West Highland White Terrier, Collie, Schnauzer, Cairn Terrier, Samoyed and Cavalier King Charles Spaniel), which demonstrated substantial intra-breed differences in allele frequencies. When SNPs were examined for an association with diabetes by case:control analysis significant associations were observed for IL-4 in three breeds, the Collie, Cairn Terrier and Schnauzer and for IL-10 in the Cavalier King Charles Spaniel. These results suggest that canine cytokine genes regulating the TH1/TH2 immune balance might play a contributory role in determining susceptibility to diabetes in some breeds.
There are few reports on the clinical appearance, prognosis, and risk factors for gestational diabetes mellitus (GDM) in dogs.
To describe the clinical characteristics of GDM in dogs.
Thirteen dogs with GDM.
Retrospective study. Medical records were reviewed and owners and referring veterinarians were contacted for follow-up information.
Nordic Spitz breeds (11/13 dogs) were overrepresented in the case material. Diagnosis was established at a median of 50 days after mating (range, 32-64). Median glucose concentration at diagnosis was 340 mg/dL (18.9 mmol/L) (range, 203-587). One dog was euthanized at diagnosis, 5 bitches were treated with insulin until whelping, and in 7 dogs, pregnancy was terminated within 4 days of diagnosis. One dog died after surgery. Tight glycemic control was not achieved in any of the insulin-treated dogs during pregnancy. Diabetes mellitus (DM) resolved in 7 dogs at a median of 9 days after the end of their pregnancies and DM was permanent in 4 dogs. Puppy mortality was increased compared with offspring of healthy dams.
This report suggests that GDM affects mainly middle-aged bitches in the 2nd half of pregnancy with a breed predisposition toward Nordic Spitz breeds. GDM may resolve within days to weeks after pregnancy has ended. Further research is needed to investigate optimal treatment regimens for dogs with GDM and risk factors for unsuccessful outcome.
Diabetes mellitus in dogs shares many characteristics with the human type 1 disease and virtually all diabetic dogs require insulin therapy to control hyperglycaemia. Insulin deficiency is suspected to result from immune-mediated destruction of pancreatic beta cells in some cases. Human patients suffering from Type 1A (immune-mediated) diabetes or latent autoimmune diabetes of the adult (LADA) demonstrate circulating autoantibodies against the 65kDa isoform of glutamic acid decarboxylase (GAD65) and/or insulinoma antigen-2 (IA-2). The aims of the current study were to develop radio-immunoassays to detect serum antibodies against recombinant canine GAD65 and IA-2 and to identify diabetic dogs showing serological evidence of autoreactivity to these pancreatic beta cell antigens. Canine GAD65 and the 3' end of IA-2 (coding for amino acids 771-979 of the intracellular domain) were amplified by PCR from cDNA prepared from canine insulinoma tissue and cloned into the pCRII vector. The canine sequences were later confirmed by identifying GAD2 and PTPRN genes from the dog genome assembly. Recombinant (35)S-methionine-radiolabelled canine GAD65 and IA-2 (771-979) proteins were used in radio-immunoprecipitation assays to screen sera from 30 newly diagnosed diabetic dogs and 30 control dogs. Four of 30 canine diabetic patients had significant GAD65 autoreactivity (p<0.01) compared to controls and 3 dogs were positive for autoantibodies to IA-2 (771-979). Two diabetic dogs showed dual autoantigen reactivity. These preliminary data indicate that serological reactivity to GAD65 and IA-2 is present in a proportion of diabetic dogs and suggests that, in some cases, canine diabetes is associated with an autoimmune response to these antigens.
Diabetes is a fascinating, disease complex. Although much progress has been made in the last three decades to unravel the mysteries behind its multifaceted expressions, much work lies ahead. In dogs diabetes is not identified until late in the disease process. Future research might be directed at identifying early markers of the disease as an aid to improving current modes of treatment.
In conclusion, interaction between the immune and endocrine systems is highly complex. Generally, abnormalities of T suppressor cells, a result of HLA antigen genetic abnormalities, result in autoimmunity that causes endocrine gland destruction and hormone deficiency, as seen in lymphocytic thyroiditis of dogs, type I DM, hypoparathyroidism, hypoadrenocorticism, and APS. On the other hand, endocrine deficiency (hypothyroidism, DM) or excess (hyperadrenocorticism) states may cause abnormalities of cell-mediated and antibody-associated immunity, leading to susceptibility to a variety of viral, bacterial, and fungal infections. It is hoped that this article sheds some light on the complex and highly integrated endocrine-immune interactions.
Serum glucose and plasma C-peptide response to i.v. glucagon administration was evaluated in 24 healthy dogs, 12 dogs with untreated diabetes mellitus, 30 dogs with insulin-treated diabetes mellitus, and 8 dogs with naturally acquired hyperadrenocorticism. Serum insulin response also was evaluated in all dogs, except 20 insulin-treated diabetic dogs. Blood samples for serum glucose, serum insulin, and plasma C-peptide determinations were collected immediately before and 5, 10, 20, 30, and (for healthy dogs) 60 minutes after i.v. administration of 1 mg glucagon per dog. In healthy dogs, the patterns of glucagon-stimulated changes in plasma C-peptide and serum insulin concentrations were identical, with single peaks in plasma C-peptide and serum insulin concentrations observed approximately 15 minutes after i.v. glucagon administration. Mean plasma C-peptide and serum insulin concentrations in untreated diabetic dogs, and mean plasma C-peptide concentration in insulin-treated diabetic dogs did not increase significantly after i.v. glucagon administration. The validity of serum insulin concentration results was questionable in 10 insulin-treated diabetic dogs, possibly because of anti-insulin antibody interference with the insulin radioimmunoassay. Plasma C-peptide and serum insulin concentrations were significantly increased (P < .001) at all blood sampling times after glucagon administration in dogs with hyperadrenocorticism, compared with healthy dogs, and untreated and insulin-treated diabetic dogs. Five-minute C-peptide increment, C-peptide peak response, total C-peptide secretion, and, for untreated diabetic dogs, insulin peak response and total insulin secretion were significantly lower (P < .00l) in diabetic dogs, compared with healthy dogs, whereas these same parameters were significantly increased (P < .01) in dogs with hyperadrenocorticism, compared with healthy dogs, and untreated and insulin-treated diabetic dogs. Although not statistically significant, there was a trend for higher plasma C-peptide concentrations in untreated diabetic dogs compared with insulin-treated diabetic dogs during the glucagon stimulation test. Baseline C-peptide concentrations also were significantly higher (P < .05) in diabetic dogs treated with insulin for less than 6 months, compared with diabetic dogs treated for longer than 1 year. Finally, 7 of 42 diabetic dogs had baseline plasma C-peptide concentrations greater than 2 SD (ie, > 0.29 pmol/mL) above the normal mean plasma C-peptide concentration; values that were significantly higher, compared with the results in healthy dogs (P < .001) and with the other 35 diabetic dogs (P < .001). In summary, measurement of plasma C-peptide concentration during glucagon stimulation testing allowed differentiation among healthy dogs, dogs with impaired beta-cell function (ie, diabetes mellitus), and dogs with increased beta-cell responsiveness to glucagon (ie, insulin resistance). Plasma C-peptide concentrations during glucagon stimulation testing were variable in diabetic dogs and may represent dogs with type-1 and type-2 diabetes or, more likely, differences in severity of beta-cell loss in dogs with type-1 diabetes.
An unusual combination of three endocrinopathies found in one dog is described. A six-year-old, spayed female, mixed-breed dog presented with polyuria, polydipsia, polyphagia, and weight loss. She was diagnosed with diabetes mellitus but was suspected of having insulin resistance and was diagnosed subsequently with hyperadrenocorticism. Persistent hypercholesterolemia led to the suspicion and eventual diagnosis of hypothyroidism. The dog has responded well to medical therapy, and her clinical signs and biochemical changes have resolved. A literature search did not identify a similar-reported polyendocrinopathy.
In insulin-dependent diabetes mellitus (IDDM) in humans and BB rats, islet cell autoimmunities associated with autoantibodies to a beta-cell protein of 64,000 Mr (64K) have been described. We report that sera from newly diagnosed nonobese diabetic (NOD) mice similarly contain an autoantibody that immunoprecipitates 64K autoantigen from detergent lysates of [35S]methionine-labeled murine islet cells. The autoantibody was detectable by weaning; it disappeared within weeks after diabetes onset and was absent in older nondiabetic NOD mice as well as all of three non-diabetes-prone control strains tested. The 64K beta-cell autoantigen may be a critical target in the immunopathogenesis of IDDM.
Antibodies in sera from newly diagnosed insulin-dependent diabetes mellitus (IDDM) patients are directed to a human islet cell protein of relative molecular mass (Mr) 64,000. Since IDDM seems to develop after a prodromal period of beta-cell autoimmunity, this study has examined whether 64,000 Mr antibodies could be detected in 14 individuals who subsequently developed IDDM and five first degree relatives who have indications of altered beta-cell function. Sera were screened by immunoprecipitation on total detergent lysates of human islets and positive sera retested on membrane protein preparations. Antibodies to the 64,000 Mr membrane protein were consistently detected in 11/14 IDDM patients, and in all 5 first degree relatives. 10 IDDM patients were already positive in the first samples, obtained 4-91 mo before the clinical onset of IDDM, whereas 1 patient progressed to a high 64,000 Mr immunoreactivity, at a time where a commencement of a decline in beta-cell function was detected. 64,000 Mr antibodies were detected before islet cell cytoplasmic antibodies (ICCA) in two patients. In the control groups of 21 healthy individuals, 36 patients with diseases of the thyroid and 5 SLE patients, the 64,000 Mr antibodies were detected in only one individual, who was a healthy sibling to an IDDM patient. These results suggest that antibodies against the Mr 64,000 human islet protein are an early marker of beta-cell autoimmunity and may be useful to predict a later development of IDDM.
Viable rat islet cells were used to detect islet cell surface antibodies (ICSA) in the sera of diabetic and control patients. ICSA were present in almost all recent-onset insulin-dependent diabetics younger than 30 yr (15/16); their incidence in other diabetics (6/22) was also higher than in normal controls (1/18) or in patients with autoimmune thyroiditis (1/12). The varying specificity of the ICSA for the different islet cell types led to the recognition of class I sera, whose ICSA bind exclusively to B cells, class II sera, binding only to A and pancreatic polypeptide (PP) cells and class III sera, reacting with the three islet cell types but not with D cells. Most recent-onset insulin-dependent diabetics younger than 30 contained class I-ICSA, which is consistent with an autoimmune basis of their disease and with an involvement of surface antibodies in the B cell destruction. The presence of class II ICSA in three older diabetics and in one normal control raises the question whether autoimmune reactions against A and PP cells exist and are associated with a distinct entity in islet disease. It is concluded that the autoimmune form of diabetes mellitus represents a heterogeneous group, in which ICSA-positive patients can be distinguished on the basis of their ICSA-binding to one or more islet cell types. Three techniques can be used for the further identification of circulating ICSA, namely binding experiments with purified A or B cells, electron microscopical analysis of ICSA-binding islet cells purified by fluorescence-activated cell sorting, and the immunocytochemical characterization of ICSA-positive cells.
Antibodies reacting with human pancreatic islet cells were found by immunofluorescence in the sera of 51 of 105 children with diabetes mellitus of recent onset. These antibodies were of IgG class, and several of them fixed complement and reacted with pancreatic islets of other species. Thyroid microsomal and/or gastric-parietal-cell antibodies were found in only 10 of the patients with islet-cell antibodies, and none of them had adrenal antibodies. These findings contrast with previous reports which have stressed the rarity of islet-cell antibodies in adult diabetics and their occurrence only in patients with other evidence of autoimmune disease.
Using an indirect immunofluorescence test on suspensions of viable, insulin-producing islet cells from rats, we found that 32 per cent (28/88) of insulin-treated patients with juvenile diabetes have islet-cell-surface antibodies in their circulation. These antibodies also occurred in four of nine children with glucose intolerance, in one of 24 healthy children and in nondiabetic children with thyroid disorders. In the diabetic children, the immunofluorescent reaction was inhibited by preadsorption of serum to islet cells but was little affected by preadsorption to rat hepatocytes or erythrocytes or to acetone powders of various rat tissues, including pancreas. These results show that organ-specific, nonspecies-specific antibodies reactive with the cell surface of the islet cells can be present in serum from diabetic children, and provide an approach to investigation of immunopathological aspects of diabetes mellitus.
The pancreatic islet beta-cell autoantigen of relative molecular mass 64,000 (64K), which is a major target of autoantibodies associated with the development of insulin-dependent diabetes mellitus (IDDM) has been identified as glutamic acid decarboxylase, the biosynthesizing enzyme of the inhibitory neurotransmitter GABA (gamma-aminobutyric acid). Pancreatic beta cells and a subpopulation of central nervous system neurons express high levels of this enzyme. Autoantibodies against glutamic acid decarboxylase with a higher titre and increased epitope recognition compared with those usually associated with IDDM are found in stiff-man syndrome, a rare neurological disorder characterized by a high coincidence with IDDM.
Antibodies reacting with proinsulin but not with insulin determinants have been observed recently in Type I diabetes. We describe here that ELISA-determined proinsulin autoantibodies (IgG-PAA) also occur in first-degree relatives of IDDM patients (38/513, 7.4% vs 1.9% in controls, P less than 0.025). In contrast to insulin autoantibodies (IgG-IAA) and islet cell antibodies (ICA) no association with HLA type was found. Furthermore, IgG-PAA occur independently of IgG-IAA and ICA. We conclude that the humoral autoimmune response to proinsulin determinants is under separate genetic control.
Voltage-dependent calcium channels are important in the control of calcium influx into excitable cells. With the use of cells isolated from a glucose-responsive rat insulinoma, the effect of the calcium-channel blocker nitrendipine on insulin release was examined. When 50 nM nitrendipine was added with a stimulatory glucose concentration (30 mM), first-phase insulin release was preserved, whereas the second phase was inhibited by 39.4 +/- 5.3%. When 50 nM nitrendipine was also present during basal and stimulated insulin release, the insulin release from fresh cells was significantly less during both phases compared with cells not exposed to nitrendipine (P less than 0.05). In cells cultured for 1 day in 30 mM glucose, a diminished insulin response was seen on stimulation with 30 mM glucose. Nitrendipine (50 nM) did not lead to a further decrease in insulin release. Saturable binding sites in homogenate, whole cells, and purified plasma membranes prepared from the insulinoma were characterized using [3H]nitrendipine. The Kd (in pM) for homogenate from uncultured cells was 225 +/- 34 (n = 11), whereas the Bmax (in fmol/mg protein) was 52 +/- 5. The number of apparent binding sites for [3H]nitrendipine was reduced by approximately 50% in cultured cells (Bmax = 30 +/- 5 fmol/mg protein). The reduction in insulin release from cultured cells correlated well with the reduction in nitrendipine binding. It is concluded that the decrease in the number of apparent binding sites for nitrendipine after culture represents a reduction in functional calcium channels associated with influx of calcium and insulin release.
A workshop sponsored by the National Institute of Child Health and Human Development was held in June 1988 to discuss the initial events in the pathogenesis of insulin-dependent diabetes and to make recommendations for future studies. Better definition of immunological markers to reliably predict the disease will enable the detection and study of the earliest pathogenic events involved. The precise autoimmune mechanisms and the role of the environment, both in the initiation of the disease process and precipitation of clinically overt disease, need to be accurately determined to define strategies that might eventually lead to its prevention.
Antibodies in serums from newly diagnosed insulin-dependent (type I) diabetes mellitus (IDDM) patients and individuals experiencing early phases of beta-cell destruction specifically immunoprecipitate a minor pancreatic islet cell membrane protein of 64,000 Mr (64K). In this report, we demonstrate the use of two-dimensional (2-D) gel electrophoresis to unambiguously identify the 64K antigen. By nonequilibrium pH-gradient gel electrophoresis in the first dimension and sodium dodecyl sulphate-polyacrylamide gel electrophoresis in the second dimension, the 64K protein separates into two components, designated alpha and beta, that differ in size but display identical charge heterogeneity. The high resolution of the 2-D method efficiently separates the 64K components from background proteins in immunoprecipitates from crude detergent lysates of islets. The background proteins were identified as major cellular proteins carried nonspecifically through the immunoprecipitation procedure. The high affinity and specificity of the 64K autoantibodies were demonstrated by the exclusive and greater than 1000-fold purification of this minor protein by immunoprecipitation with IDDM serums. The 2-D analyses did not reveal additional proteins specifically immunoprecipitated by IDDM serums, suggesting that the 64K protein is the only protein antigen specifically and consistently recognized by IDDM autoantibodies in the relatively stringent conditions of immunoprecipitation. Moreover, the 2-D analyses demonstrate that purification of membrane protein fractions from both human and rat islets before the immunoprecipitation efficiently removes background proteins and substantially increases the specificity of 64K autoantibody measurements by traditional methods.
An important role for calcium in the cellular events leading to insulin secretion is supported by many studies. However, simultaneous measurements of changes in intracellular free Ca2+ concentrations [( Ca2+]i) and insulin release in response to secretagogues have not been performed. Using cells isolated from a glucose-responsive insulinoma, changes in [Ca2+]i were measured with the fluorescent calcium probe quin2. With the nutrient secretagogues glucose (30 mM) and D,L-glyceraldehyde (GA; 20 mM), [Ca2+]i increased slowly, reaching a peak approximately 15 min after addition of the stimulus, while KCl (25 mM) and carbachol (2 mM) led to a rapid but transient increase in [Ca2+]i. Glucose increased [Ca2+]i from 104 +/- 6 (mean +/- SEM) to 248 +/- 31 mM (n = 13), and GA caused a rise in [Ca2+]i from 96 +/- 6 to 280 +/- 39 nM (n = 4). KCl and carbachol caused a rise from 107 +/- 6 to 184 +/- 5 nM and from 98 +/- 5 to 157 +/- 5 nM, respectively (n = 5 each). When insulin release was measured simultaneously with changes in [Ca2+]i and compared to unstimulated cells, the following results were obtained. During the first 5 min of stimulation, high glucose caused a 90 +/- 12% increase in insulin release and a 72 +/- 11% rise in [Ca2+]i (n = 5). GA evoked a 122 +/- 30% increase in insulin secretion, with a 82 +/- 17% rise in [Ca2+]i (n = 3). Both KCl and carbachol caused a 58 +/- 9% increase in insulin release, with 7 +/- 4% and 50 +/- 2% rises in [Ca2+]i, respectively (n = 4 each). Insulin release was also measured in a perifusion system. It was shown that glucose (30 mM), GA (20 mM), and alpha-ketoisocaproate (30 mM) caused a biphasic release of insulin, while KCl (25 mM) and carbachol (2 mM) caused a monophasic release. The results show that [Ca2+]i increases during the stimulation of insulin secretion when measured simultaneously on the same beta-cells. However, while these changes coincide, a simple direct quantitative relationship between insulin release and the rise in [Ca2+]i could not be demonstrated.
DURING the past decade a wealth of information concerning the pathogenesis of Type I diabetes has become available. Two spontaneous animal models of the disease have been discovered and characterized (the Biobreeding rat and the non-obese diabetic mouse); the importance of a gene or genes in the major histocompatibility complex in Type I diabetes of human beings, of mice, and of rats has been appreciated; and the prognostic importance of selected assays for islet-cell antibodies has been defined. T-cell abnormalities that precede diabetes have been discovered. Evidence has suggested that progressive loss of first-phase insulin secretion precedes diabetes, and immunologic . . .
IgG and IgM class insulin autoantibodies were measured by an enzyme-linked immunosorbent assay in sera from members of the Barts-Windsor-Middlesex prospective family study for Type 1 (insulin-dependent) diabetes. One hundred and twelve individuals from 28 families were selected for study on the basis of a clearly defined islet cell antibody status. IgG insulin autoantibodies were found to be significantly associated with islet cell antibody positive (n = 30) versus islet cell antibody negative (n = 57) first degree family relatives (p = 0.002), with increased significance (p = 0.0003) if complement-fixing (CF)-islet cell antibody individuals (n = 20) only were considered. In addition, a significant association of IgG insulin autoantibodies with subsequent development of diabetes was observed within the CF-islet cell antibody positive group (p less than 0.0003). No such associations were found for IgM insulin autoantibodies, but a higher prevalence of these autoantibodies was observed in islet cell antibody negative first degree relatives (n = 57) compared with a control group of 73 Blood Bank donors (p = 0.00007), and they were significantly associated with siblings (n = 48) rather than parents (n = 39), (p = 0.001). We conclude that the presence of IgG insulin autoantibodies and CF-islet cell antibodies confer more risk for future development of diabetes than the presence of either marker alone.
Indirect immunofluorescence on normal canine pancreatic tissue fixed in Bouin's solution was used to detect islet cell antibodies in dogs with diabetes mellitus, other endocrine diseases, and pancreatitis. 18 of 25 dogs with diabetes mellitus alone, 2 of 8 dogs with diabetes mellitus and concurrent pancreatitis, and 2 of 2 dogs with diabetes mellitus and concurrent pancreatic exocrine insufficiency were positive for autoantibody. 2 of 12 dogs with hypoadrenocorticism, 3 of 6 dogs with hyperadrenocorticism, 6 of 28 dogs with hypothyroidism and one of 19 dogs with pancreatitis alone were also antibody positive. None of 20 healthy dogs or 20 dogs with disorders other than those of the pancreas or endocrine organs were antibody positive. Islet cell antibodies were demonstrated in dogs with diabetes mellitus and other endocrine disorders. The possibility of autoimmune involvement in the development of diabetes mellitus in the dog should be considered.
Antibodies to pancreatic islet cells were found by immunofluorescence in the sera of 13 patients with multiendocrine deficiencies associated with organ-specific autoimmunity. 10 of these patients were diabetic. The antibodies were complement fixing and of IgG class; titres varied from 1 to 160 and were independent of insulin treatment. The presence of organ-specific pancreatic antibodies supports the hypothesis of an autoimmune form of diabetes mellitus put forward to explain the histological " insulitis " found in selected cases of this disease. This new marker allows the segregation of a homogeneous group of insulin-dependent diabetics who may well prove to have a different metabolic pattern from that in other forms of inherited diabetes mellitus.
Charcoal premixed with dextran of average molecular weight 80,000 almost instantly adsorbs free insulin but rejects antibody-bound insulin. The use of such dextran-coated charcoal makes simpler and more rapid the immunoassay of insulin in biologic fluids, using radioisotope dilution with 131I-insulin and “biopsy” of the insulin pool by antibody to insulin. The procedure here described yields a straight line graph when insulin added is plotted against insulin recovered.
In a prospective investigation of the prediabetic period before onset of type 1 (insulin-dependent) diabetes, HLA genotypes were determined in 582 healthy parents and siblings of 160 affected children. Islet cell antibody was sought by both the conventional (ICA-IgG) and the complement fixation (CF-ICA) techniques during regular prospective observation over a mean period of 2.0 years. 4 siblings and 2 parents became diabetic; the interval before detection of any biochemical abnormality exceeded a year in 4 of these (range 3-30 months), and in all cases ICA-IgG was positive from the outset, CF-ICA being positive in 5. These observations suggest that the initiation of pathogenesis may precede the abrupt clinical onset of diabetes by several years, even in children. This has important implications, both for research and for possible future prophylaxis.
We studied the release of insulin, glucagon, and somatostatin in response to glucose, glyceraldehyde (GA), and α-ketoisocaproate (KIC) from rat kidneys containing transplanted insulinomas. Kidneys were perfused about 11 wk after transplantation when the plasma glucose concentration of the fed animals had decreased from 180 ± 7 to 95.1 ± 9.9 mg/dl and plasma insulin concentrations had increased from 2.6 ± 0.5 to 14.2 ± 2.0 ng/ml. The insulin content of the tumorcontaining kidney ranged from 40 to 679 μg; the glucagon and somatostatin concentrations ranged from undetectable levels to 3.7 μg and 248 ng, respectively. The average response to 30 mM glucose and 10 mM GA was a four- to fivefold increase in insulin secretion, whereas 30 mM KIC caused a 16- to 28-fold increase. In vitro stimulation of the insulinoma with 30 mM glucose primed the β-cell response to a second stimulus following a short rest period. Cytochalasin B did not enhance this primed glucose response. Diazoxide inhibited glucose, GA, and KIC-stimulated insulin release. Glucose, GA, and KIC stimulated glucagon release in 2 of 17 insulinomas studied here.
Somatostatin release was not seen in any of the experiments. These findings show that this islet cell tumor transplanted under the kidney capsule releases insulin in response to physiologic and model fuel substances. Thus, this particular transplantable tumor offers an opportunity to study the biochemistry and biophysics that underlie fuel-stimulated insulin release.
The diabetic syndrome of the BB rat shows many homologies with that of human insulin-dependent diabetes and evidence that the onset of the disease is associated with the presence of autoantibodies, including islet cell surface antibodies. In this study, sera were sampled serially from weaning to 157 days of age from 26 BB rats in two low-incidence litters, and 22 rats of three high-incidence litters. Clinical and metabolic variables were monitored concurrently with blood lymphocyte counts. Islet morphology was correlated at sacrifice. In the high-incidence litters, eight rats developed insulin-dependent diabetes, five impaired glucose tolerance, and the remaining nine all showed insulitis. In the low-incidence litters, only one animal showed impaired glucose tolerance and another insulitis. In the high-incidence litters 16 rats (73%) had islet cell surface antibodies compared with 4 out of 26 (15%) low-incidence controls (p less than 0.002). Antibodies reactive with Wistar rat spleen lymphocytes were present in all high-incidence rats compared with 19% (5 out of 26) among the control litters (p less than 0.002). Time courses of islet cell surface and lymphocyte antibody appearance and their peak values varied, but already at weaning the levels of both antibodies were increased among the high-incidence litter rats (p less than 0.001). Islet cell surface and/or lymphocyte antibodies were therefore present in the majority of animals at an age where neither morphological nor metabolic evidence of the diabetic syndrome were yet detected.(ABSTRACT TRUNCATED AT 250 WORDS)
The insulin secretory response to various beta-cell secretagogues was studied in four children (ages 11, 11, 12, and 10 yr) in "early" stages or remission of type I diabetes mellitus. One child was an anti-islet antibody positive monozygotic twin of a type I diabetic subject, two children had impaired glucose tolerance and elevated levels of Ia-positive T-cells, and the fourth was in remission (off insulin) of type I diabetes 6 mo after immunotherapy. The peak first-phase (0-10 min) insulin increment after intravenous (i.v.) glucose was negligible in each patient, whereas the peak responses to i.v. glucagon, tolbutamide, arginine, and oral glucose ranged between 10% and 43% of median responses in normal control subjects. The rank order of response to a variety of secretagogues was remarkably similar in all four subjects: i.v. arginine greater than i.v. glucagon greater than oral glucose greater than i.v. tolbutamide greater than i.v. glucose. These studies indicate that a "functional" beta-cell defect, namely a complete loss of response to i.v. glucose and a partial loss to other secretagogues, exists in type I diabetic patients before complete beta-cell destruction. This alteration in beta-cell responsiveness probably underlies our prior observation of slowly progressive loss of i.v.-glucose-induced insulin release in islet cell antibody-positive siblings to type I diabetic subjects.
Spontaneous insulin-dependent diabetes mellitus (IDDM) in the BB rat is associated with the presence of antibodies to a 64-kilodalton
rat islet cell protein. These protein antibodies appeared in young animals and remained for as long as 8 weeks before the
clinical onset of IDDM. Antibodies to a 64-kilodalton human islet cell protein were found to be associated with human IDDM.
Detection of the antibodies may therefore be used to predict an early immune reaction against pancreatic B cells.
Insulin-dependent diabetic (IDD) patients have a high prevalence of circulating autoantibodies against islet of Langerhans cells at the time of diagnosis1-4. Inflammatory cells within the islets5, leukocyte migration inhibition in response to pancreatic antigens6 and an association with certain HLA-D/DR histocompatibility antigens7,8, have also been observed. It seems that the autoantibodies may be pathogenically relevant as they react primarily with beta-cells9, but the specific target antigen(s) have yet to be identified. In the present study we determined whether sera from insulin-dependent diabetic children are able to immunoprecipitate proteins from detergent lysates of human islet cells. We report that sera from 8 out of 10 newly diagnosed diabetic children consistently immunoprecipitate a protein having a molecular weight (Mr) of ~64,000 (64K). An additional protein (38K) was precipitated from islet cells obtained from a HLA-DR3-positive donor. Neither of the proteins was precipitated by non-diabetic sera nor detected in immunoprecipitates from human lymphocyte lysates. It is suggested that the 64K and/or 38K protein components may represent cell-specific target antigens in insulin-dependent diabetes.
Differential sensitivity to beta cell secretagogues in “early”, type I diabetes mellitus
- Ganda