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G Tonolo,
M Velussi,
E Brocco,
C Abaterusso,
A Carraro,
G Morgia,
A Satta,
R Faedda,
A Abhyankar, H Luthman,
R Nosadini
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ABSTRACT: The factors determining the course of glomerular filtration rate (GFR) and albumin excretion rate (AER) and the expression of mRNA of slit diaphragm (SD) and podocyte proteins in microalbuminuric, hypertensive type II diabetic patients are not fully understood. GFR, AER, and SD protein mRNA were studied in 86 microalbuminuric, hypertensive, type II diabetics at baseline and after 4-year random double-blind treatment either with 40 mg simvastatin (Group 1) or with 30 g cholestyramine (Group 2) per day. Both groups had at baseline a GFR decay per year in the previous 2-4 years of 3 ml/min/1.73 m(2). Both Groups 1 and 2 showed a significant decrease of low-density lipoprotein cholesterol levels after simvastatin and cholestyramine treatment (P<0.01). No change from base line values was observed as for hs-C-reactive protein and interleukin-6. A significant decrease of 8-hydroxydeoxyguanosine urinary excretion was observed after simvastatin treatment. GFR did not change from baseline with simvstatin, whereas a decrease was observed with cholestyramine treatment (simvastatin vs cholestyramine: -0.21 vs -2.75 ml/min/1.73 m(2), P<0.01). AER decreased in Group 1 (P<0.01), but not in Group 2 patients. Real-time polymerase chain reaction measurement of mRNA SD proteins (CD2AP, FAT, Actn 4, NPHS1, and NPHS2) significantly increased in kidney biopsy specimens after simvastatin, but not cholestyramine treatment. Simvastatin, but not cholestyramine, 4-year treatment maintains steady patterns of GFR, and improves AER and expression of SD proteins in type II diabetes, despite similar hypocholesterolemic effects in circulation.
Kidney International 08/2006; 70(1):177-86. · 6.61 Impact Factor
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Journal of Medical Genetics 05/2004; 41(4):e39. · 6.36 Impact Factor
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ABSTRACT: Atopic dermatitis (AD) is caused by genetic and environmental factors that interact to determine disease susceptibility and severity. Several lines of evidence suggest that the IL-4 gene and the IL-4-receptor alpha (IL-4Ralpha) gene are involved in the development of atopic diseases.
The objective of this study was to evaluate the possible involvement of the chromosomal regions 5q31 and 16p12, which include the genes coding for the IL-4 and the IL-4Ralpha in AD.
We conducted linkage analysis and association studies using the microsatellite markers D16S298 and D16S403 and a single nucleotide polymorphism in the promoter region of the IL-4 gene (- 590C/T) in 406 Swedish families with at least two siblings affected with AD, in total 1514 individuals.
We report linkage (P < 0.005) to the - 590C/T polymorphism in the promoter of the IL-4 gene for the semiquantitative trait severity score of AD. Neither linkage nor association was found to the IL-4Ralpha chromosomal region.
Clinical & Experimental Allergy 09/2002; 32(8):1199-202. · 5.03 Impact Factor
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ABSTRACT: Background Atopic dermatitis (AD) is caused by genetic and environmental factors that interact to determine disease susceptibility and severity. Several lines of evidence suggest that the IL-4 gene and the IL-4-receptor alpha (IL-4Rα) gene are involved in the development of atopic diseases.Objective The objective of this study was to evaluate the possible involvement of the chromosomal regions 5q31 and 16p12, which include the genes coding for the IL-4 and the IL-4Rα in AD.Methods We conducted linkage analysis and association studies using the microsatellite markers D16S298 and D16S403 and a single nucleotide polymorphism in the promoter region of the IL-4 gene (− 590C/T) in 406 Swedish families with at least two siblings affected with AD, in total 1514 individuals.Results and Conclusion We report linkage (P < 0.005) to the − 590C/T polymorphism in the promoter of the IL-4 gene for the semiquantitative trait severity score of AD. Neither linkage nor association was found to the IL-4Rα chromosomal region.
Clinical & Experimental Allergy 07/2002; 32(8):1199 - 1202. · 5.03 Impact Factor
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ABSTRACT: Atopic dermatitis is a hereditary, pruritic, inflammatory and chronic skin disease that typically presents in early childhood and may continue or recur later. The etiology of atopic dermatitis is unknown, but several lines of evidence indicate that it is a multifactorial disorder caused by the combined influence of genetic and environmental factors, even though the relative contributions of genes and environment are not known. To identify important loci that contribute to the development of atopic dermatitis, we conducted a genome-wide linkage analysis with 367 microsatellite markers, using a non-parametric affected relative-pair method in 109 pedigrees. Three qualitative phenotypes and one semi-quantitative phenotype were studied. For the phenotype atopic dermatitis, linkage to chromosome region 3p24-22 was found. For another phenotype, atopic dermatitis combined with raised allergen-specific IgE levels, a suggestive linkage was found to chromosome region 18q21. For the semi-quantitative phenotype severity score of atopic dermatitis, suggestive linkage was found to chromosome regions 3q14, 13q14, 15q14-15 and 17q21. Identifying chromosome regions linked to susceptibility genes for atopic dermatitis provides a platform from which the search for atopic dermatitis genes can proceed.
Human Molecular Genetics 07/2002; 11(13):1539-48. · 7.64 Impact Factor
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ABSTRACT: The major diabetes quantitative trait locus (Niddm1), which segregates in crosses between GK rats affected with spontaneous type 2-like diabetes and normoglycemic F344 rats, encodes at least two different diabetes susceptibility genes. Congenic strains for the two subloci (Niddm1f and Niddm1i) have been generated by transfer of GK alleles onto the genome of F344 rats. Whereas the Niddm1f phenotype implicated insulin resistance, the Niddm1i phenotype displayed diabetes related to insulin deficiency. Individual islets from 16-week-old congenic rats were characterized for insulin release and oxygen tension (pO(2)). In the presence of 3 mmol/l glucose, insulin release from Niddm1f and Niddm1i islets was approximately 5 pmol. g(-1). s(-1) and pO(2) was 120 mmHg. Similar recordings were obtained from GK and F344 islets. When glucose was raised to 11 mmol/l, insulin release increased significantly in Niddm1f and F344 islets but was essentially unchanged in islets from GK and Niddm1i. The high glucose concentration lowered pO(2) to the same extent in islets from all strains. Addition of 1 mmol/l tolbutamide to the perifusion medium further increased pulsatile insulin release threefold in all islets. The pulse frequency was approximately 0.4 min(-1). alpha-Ketoisocaproate (11 mmol/l) alone increased pulsatile insulin release eightfold in islets from Niddm1f, Niddm1i, and control F344 rats but had no effect on insulin release from GK islets. These secretory patterns in response to alpha-ketoisocaproate were paralleled by reduction of pO(2) in Niddm1f, Niddm1i, and control F344 islets and no change of pO(2) in GK islets. The results demonstrate that Niddm1i carries alleles of gene(s) that reduce glucose-induced insulin release and that are amenable to molecular identification by genetic fine mapping.
Diabetes 01/2002; 50(12):2737-43. · 8.29 Impact Factor
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ABSTRACT: Experimental autoimmune neuritis (EAN) is the principal animal model for Guillain-Barré syndrome (GBS), an inflammatory disease of the peripheral nervous system. Little is known on the genetic regulation of these diseases. We provide the first genetic linkage analysis of EAN. Susceptibility to EAN in a rat F2 population segregated with high levels of anti-PNM IgG, as well as IgG2b and IgG2c isotype levels, which support that disease genes regulate preferential Th1/Th2 differentiation. Linkage analysis demonstrated co-localization of EAN loci with reported susceptibility loci for experimental arthritis and/or encephalomyelitis and a new region on chromosome 17. Further dissection of these loci may disclose disease pathways in GBS.
Journal of Neuroimmunology 11/2001; 119(2):166-74. · 2.96 Impact Factor
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ABSTRACT: Alport syndrome (AS) is a hereditary disease of the glomerular basement membrane in the kidney characterized by progressive renal failure, sensorineural deafness, and/or ocular abnormalities. In contrast to the well-known X-linked phenotype, very little is known about the autosomal dominant form. Rare autosomal forms of AS have been described with mutations in COL4A3 and COL4A4 at chromosome region 2q35-q37, but there have been no descriptions of dominant forms due to a mutation in COL4A4.
We describe a Sardinian family with a classical AS-phenotype plus hypercholesterolaemia, a clinical feature also present in Fechtner syndrome (FS), a disease that segregates as an autosomal dominant trait.
A suggestive linkage (LOD=2.7) between AS and the COL4A3/A4 locus at 2q35-q37 was identified. Other candidate collagen genes encoding basement membrane collagen (COL4A1/A2 and COL4A5/A6) were excluded by linkage analysis (13q33-q34 and Xq22), or by sequence (COL4A3). DNA sequence analysis of the COL4A4 gene revealed that the Lys325Asn mutation was present in all affected family members, but was absent in all unaffected members and in a random sample of the Sardinian population. A clear indication of a gene-dosage effect was seen in the most severely affected family member, since she carried the mutation in the homozygous form.
These data confirm the importance of collagen 4A4 as a component in the structural integrity of the glomerular basement membrane and confirm the phenotypic and genetic heterogeneity of collagen disorders.
Nephrology Dialysis Transplantation 11/2001; 16(10):2008-12. · 3.40 Impact Factor
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ABSTRACT: Several quantitative trait loci (QTLs) regulating the risk of experimental arthritis have been identified by genome-wide linkage analyses, but only the MHC has thus far been reported to transfer arthritis susceptibility in congenic animals. We have produced a congenic strain for Oia3, a genetic factor originally identified as an oil-induced arthritis (OIA) QTL in arthritis-prone DA rats. A 46 cM telomeric region of chromosome 10 encompassing Oia3 was transferred from DA rats to MHC-identical but minutely arthritis-susceptible LEW.1AV1 rats by selective breeding. Arthritis development was provoked in Oia3-congenic rats by intradermal injection of different adjuvant oils. One successful arthritis trigger was squalene, which is approved for vaccinations in humans and has been implicated in Gulf War syndrome. The endogenous cholesterol precursor squalene induced T cell infiltration into joints and macroscopic arthritis in Oia3-congenic rats and DA rats, whereas LEW.1AV1 rats were almost resistant. Arthritis onset, approximately 14 days post-injection, coincided with arrested body-weight gain and increased plasma levels of the inflammation markers fibrinogen and alpha 1-acid glycoprotein. Congenic rats displayed intermediate phenotypes compared with the two parental strains, and similar to rheumatoid arthritis in humans, female preponderance was observed in Oia3-congenic rats. Finally, recombinant rat strains were constructed and were used to map a susceptibility gene(s) in females to a telomeric 4--19 cM Oia3 subregion. The experimental system described allows transformation of multifactorial arthritis susceptibility into dichotomous phenotypes.
Human Molecular Genetics 04/2001; 10(6):565-72. · 7.64 Impact Factor
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ABSTRACT: Genetic analysis of the diabetic GK rat has revealed several diabetes susceptibility loci. Congenic strains have been established for the major diabetes locus, Niddm1, by transfer of GK alleles onto the genome of the normoglycemic F344 rat. Niddm1 was dissected into two subloci, physically separated in the congenic strains Niddm1b and Niddm1i, each with at least one disease susceptibility gene. Here we have mapped Niddm1b to 1 cM by genetic and pathophysiological characterization of new congenic substrains for the locus. The gene encoding insulin-degrading enzyme (IDE:) was located to this 1 cM region, and the two amino acid substitutions (H18R and A890V) identified in the GK allele reduced insulin-degrading activity by 31% in transfected cells. However, when the H18R and A890V variants were studied separately, no effects were observed, demonstrating a synergistic effect of the two variants on insulin degradation. No effect on insulin degradation was observed in cell lysates, indicating that the effect is coupled to receptor-mediated internalization of insulin. Congenic rats with the IDE: GK allele displayed post-prandial hyperglycemia, reduced lipogenesis in fat cells, blunted insulin-stimulated glucose transmembrane uptake and reduced insulin degradation in isolated muscle. Analysis of additional rat strains demonstrated that the dysfunctional IDE: allele was unique to GK. These data point to an important role for IDE: in the diabetic phenotype in GK.
Human Molecular Genetics 10/2000; 9(14):2149-58. · 7.64 Impact Factor
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ABSTRACT: Two Swedish brothers, 2.5 and 4 years of age, were found to fulfil all the clinical and laboratory characteristics of Laron's syndrome. They were shown to have unique missense mutations in the GH receptor gene. Both of their parents were of normal height, but they both separately carried one of the identified gene alterations. A molecular model of the first receptor alteration suggests that a collapse in three-dimensional receptor structure most likely contributed to the GH insensitivity in these patients.
European Journal of Endocrinology 08/2000; 143(1):71-6. · 3.42 Impact Factor
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ABSTRACT: High serum cholesterol is an established risk factor for cardiovascular disease and is the prime target for therapeutic intervention in large groups of patients. The development of modern treatments for this major risk factor was propelled by the early realization that forms of severe hypercholesterolemia could be caused by dominantly inherited defects in the LDL receptor or in the APOB gene. Further understanding of the mechanisms contributing to early atherosclerosis will allow for new targets for therapy. We therefore identified and investigated the genetics of families from Sardinia that have recessive inheritance of precocious hypercholesterolemia. We used five families in an analysis of linkage of the autosomal recessive hypercholesterolemia locus, termed "ARH1," to chromosome 15q25-q26. A genomewide search mapped the disease-causing gene with a LOD score of 3.3 and excluded major contributions to the phenotype of other genes. A candidate gene present in the mapped chromosome region-the ligand-activated liver-transcription-factor gene ARP1 (apolipoprotein regulatory-protein gene)-has been excluded after DNA sequencing. The close-bred nature of the Sardinian population offers unique opportunities for isolation of this hypercholesterolemia-causing gene.
The American Journal of Human Genetics 03/2000; 66(2):453-60. · 10.60 Impact Factor
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ABSTRACT: Genetic studies of the type 2 diabetes-like GK rat have revealed several susceptibility loci for the compound diabetes phenotype. Congenic strains were established for Niddm1, the major quantitative trait locus (QTL) for postprandial glucose levels, by transfer of GK alleles onto the genome of the normoglycemic F344 rat. Despite the polygenic nature of diabetes in GK, the locus-specific diabetes phenotype was retained in the congenic strain Niddmla, containing a GK-derived genomic fragment of 52 cM from the Niddm1 locus. Furthermore, Niddm1 was divided into two non-overlapping loci, physically separated in the two congenic strains Niddmlb and Niddm1i with distinct metabolic phenotypes. Both strains displayed postprandial hyperglycemia and reduced insulin action in isolated adipose cells. Furthermore, Niddm1i already exhibits a pronounced in vivo insulin secretion defect at 65 days, while Niddm1b develops a relative insulin secretory defect at 95 days. This suggests that Niddm1i impairs mechanisms common to insulin secretion in pancreatic B-cells and insulin action in adipocytes. Niddm1b rats show signs of increasing insulin resistance with age associated with obesity, hyperinsulinemia, and dyslipidemia. Moreover, the data indicated nonallelic interaction (epistasis) between Niddm1b and Niddm1i on the postprandial glucose levels. These data emphasize the pathophysiological complexity of diabetes, even within an apparently single QTL, and demonstrate the potential of the GK model in transforming the multifactorial diabetes phenotype into single traits, suitable for positional cloning.
Diabetes 01/2000; 48(12):2463-70. · 8.29 Impact Factor
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ABSTRACT: Previous studies have suggested that reactive oxygen species (ROS) are mediators in the teratogenic process of diabetic pregnancy. In an animal model for diabetic pregnancy, offspring of the H rat strain show minor dysmorphogenesis when the mother is diabetic, whereas the offspring of diabetic rats of a sister strain, U, display major morphologic malformations. Earlier studies have shown that embryonic catalase activity is higher in the H than in the U strain, and maternal diabetes increases this difference in activity. The aim of this study was to characterize the influence of genetic predisposition on diabetic embryopathy by comparing the mRNA levels of ROS-metabolizing enzymes in the two strains. We determined the mRNA levels of catalase, glutathione peroxidase, gamma-glutamylcystein-synthetase, glutathione reductase, and superoxide dismutase (CuZn-SOD and Mn-SOD) in day 11 embryos of normal and diabetic H and U rats using semiquantitative reverse transcription-polymerase chain reaction. The mRNA levels of catalase and Mn-SOD were increased in H embryos as a response to maternal diabetes, and no differences were found for the other genes. Sequence analysis of the catalase promoter indicated that the difference in mRNA levels may result from different regulation of transcription. Sequence analysis of the catalase cDNA revealed no differences between the two strains in the translated region, suggesting that the previously observed difference in the electrophoretic mobility in zymograms is due to posttranslational modifications. An impaired expression of scavenging enzymes in response to ROS excess can thus be an integral part of a genetic predisposition to embryonic dysmorphogenesis.
Diabetes 01/2000; 49(1):101-7. · 8.29 Impact Factor
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Mammalian Genome 12/1999; 10(11):1102-5. · 2.89 Impact Factor
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ABSTRACT: Multiple sclerosis (MS) is a chronic inflammatory and demyelinating disease of the central nervous system (CNS) with a complex etiology comprising a genetically determined predisposition and a suspected auto- immune pathogenesis. Experimental autoimmune encephalomyelitis (EAE) is an animal model for MS, which can be used to define susceptibility loci for autoimmune neuroinflammation. We have recently established a chronic relapsing EAE model characterized by inflammation and focal demyelination in the CNS by immunizing a variety of rat strains with the CNS-specific myelin oligodendrocyte glycoprotein (MOG). This model is more MS-like than any other rodent EAE model described up to now. Here we present the first systematic genome search for chromosomal regions linked to phenotypes of MOG-induced EAE in a (DA x ACI) F(2)intercross. A genome-wide significant susceptibility locus linked to demyelination was identified on chromosome 18. This region has not been described in inflammatory diseases affecting other organs and the responsible gene or genes may thus be nervous system specific. Other chromosomal regions showing suggestive linkage to phenotypes of MOG-induced EAE were identified on chromosomes 10, 12 and 13. The chromosome 10 and 12 regions have previously been linked to arthritis in DA rats, suggesting that they harbour immunoregulatory genes controlling general susceptibility to autoimmune diseases. We conclude that identification of susceptibility genes for MOG-induced EAE on rat chromosomes 10, 12, 13 and 18 may disclose important disease pathways for chronic inflammatory demyelinating diseases of the CNS such as MS.
Human Molecular Genetics 12/1999; 8(12):2183-90. · 7.64 Impact Factor
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Transplantation Proceedings 06/1999; 31(3):1597-9. · 1.00 Impact Factor
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ABSTRACT: The immunization of inbred Dark Agouti (DA) rats with an emulsion containing homogenized spinal cord and CFA induces chronic relapsing experimental autoimmune encephalomyelitis (EAE), a disease with many similarities to multiple sclerosis. We report here the first genome-wide search for quantitative trait loci regulating EAE in the rat using this model. We identified one quantitative trait locus on chromosome 9, Eae4, in a [DA(RT1av1) x BN(RT1n)]F2 intercross showing linkage to disease susceptibility and expression of mRNA for the proinflammatory cytokine IFN-gamma in the spinal cord. Eae4 had a larger influence on disease incidence among rats that were homozygous for the RT1av1 MHC haplotype (RT1av1 rats) compared with RT1n/av1 rats, suggesting an interaction between Eae4 and the MHC. Homozygosity for the DA allele at markers in Eae4 and in the MHC was sufficient for EAE. Thus, Eae4 is a major genetic factor determining susceptibility to EAE in this cross of DA rats. In addition, there was support for linkage to phenotypes of EAE on chromosomes 1, 2, 5, 7, 8, 12, and 15. The chromosome 12 region has been shown previously to predispose DA rats to arthritis, and the chromosome 2 region is syntenic to Eae3 in mice. We conclude that Eae4 and probably the other identified genome regions harbor genes regulating susceptibility to neuroinflammatory disease. The identification and functional characterization of these genes may disclose critical events in the pathogenesis of multiple sclerosis; understanding these events could be essential for the development of new therapies against the disease.
The Journal of Immunology 04/1999; 162(5):2581-8. · 5.79 Impact Factor
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ABSTRACT: Idiopathic Addison's disease develops as a consequence of autoimmune destruction of steroid-producing cells in the adrenal gland. A major autoantigen is 21-hydroxylase (21OH; P450c21), which is involved in the biosynthesis of cortisol and aldosterone in the adrenal cortex. We selected a number of functionally important 21OH amino acid substitutions, found in patients with congenital adrenal hyperplasia, to study their effects on the binding of 21OH autoantibodies (21OHAb) to 21OH. The ability of 21OHAb to bind in vitro transcribed and translated wild-type 21OH and five different 21OH mutant proteins was quantified by liquid-phase assays. Sera from 21OHAb-positive patients with idiopathic Addison's disease (n = 24), Graves' disease (n = 3), and insulin-dependent diabetes mellitus (n = 1) were used. While the P105L, delE196, and G291S mutations had no effect on autoantibody binding, the P453S mutation had a considerable effect, and the R483P mutation almost completely abolished binding. Synthetic peptides corresponding to linear epitopes defined by amino acids 447-461 and 477-491 were unable to compete with wild-type 21OH for binding to autoantibodies. Direct 21OH DNA sequencing could not reveal any specific genetic variation in alleles found in 21OHAb-positive patients. We conclude that the region involving R483 plays a key role in the formation of a three-dimensional epitope in a functionally important C-terminal domain of the enzyme.
The Journal of Immunology 03/1999; 162(4):2422-6. · 5.79 Impact Factor
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ABSTRACT: Changes in cytoplasmic ATP concentration were monitored in intact insulin-producing cells and correlated to changes in the activity of ATP-sensitive K+-channels (KATP channels). Luciferase was introduced into HIT M2.2 cells and whole pancreatic islets by transient expression of firefly (Photinus pyralis) luciferase cDNA. In transfected cells, extracellular addition of luciferin increased the luminescence signal to a maximum within 50-120 s. Addition of 1 microM of the mitochondrial uncoupler FCCP decreased the luminescence, an effect partly reversed upon withdrawal of the compound. High concentrations of glucose increased cytoplasmic free ATP concentration. Changes in the luminescence signal were accompanied by changes in activity of the ATP-sensitive K+-channel. Transfection per se did not deteriorate cell function, as verified by experiments showing similar changes in cytoplasmic free Ca2+-concentration, [Ca2+li, in both transfected and non-transfected cells. By measuring the cytoplasmic ATP concentration and KATP channel activity under similar experimental conditions, it was possible to establish, for the first time, a direct relationship between these two parameters. This indeed suggests that the cytoplasmic ATP concentration has a crucial role in the regulation of KATP channel activity under physiological conditions.
FEBS Letters 01/1999; 441(1):97-102. · 3.54 Impact Factor
