Tobias Warnken

• Dr. med. vet. | PhD | DECEIM
• Principal Scientist at Boehringer Ingelheim

Background Due to the high frequency of laminitis reported for both conditions, the relationship between pituitary pars intermedia dysfunction (PPID) and insulin dysregulation (ID), and the potential role of dopamine in modifying insulin secretion, requires further investigation. Objectives To evaluate the effect of pergolide mesylate on insulin s...

Background Testing for insulin dysregulation (ID) in horses is commonly performed to guide management and therapeutic strategies. Objectives To evaluate a newly developed glycemic pellets challenge (GPC) and compare results to those obtained using the low‐dose oral sugar test (OST). Animals Twenty‐four adult horses with unknown insulin status. M...

Simple Summary In horses, the hormone insulin is frequently measured in blood samples, as increased concentrations can lead to a painful condition of the hoof called laminitis. The early detection of an increased insulin concentration is essential for animal welfare. There is considerable disagreement between different measurement methods (assays)...

Both, oral and intravenous (IV) testing protocols, are recommended and still used to detect insulin dysregulation (ID) in equids. However, IV tests mainly focus on peripheral insulin resistance (IR), while oral tests assess hyperinsulinemia (HI), which are different aspects of ID. The objective of this study was to describe if horses with HI also d...

Background Oral glycemic challenge (GC) tests are recommended for diagnosis of insulin dysregulation (ID). Various protocols are used, but all have limitations in terms of palatability, ease of use, variable composition, geographic availability, or some combination of these. Hypothesis/Objective To evaluate newly developed formulations with define...

Background A glycemic challenge test is used for the diagnosis of insulin dysregulation (ID) in horses and ponies. Different forms of the test exist where the administrative route and dose of glucose vary, which makes interpretation of results challenging. Hypothesis/Objectives To evaluate the palatability of, and blood glucose and insulin respons...

Insulin dysregulation (ID) is a determinant of equine metabolic syndrome. Among the sphingolipids, ceramides contribute to the development of ID; however, the crosstalk between the liver and adipose tissue (AT) depots and the variation among AT depots in terms of ceramide metabolism are not well-understood. We aimed to characterize the sphingolipid...

Mycotoxin contaminated feed has been associated with colic of horses caused by intestinal disorders. Whether such disease conditions alter the intestinal toxin metabolism and transfer across a compromised mucosal barrier is unknown. A screening approach was used to relate blood residue levels of DON, ZEN and their metabolites to the status of the h...

Background Sphingolipids modulate insulin sensitivity in mammals. Increased synthesis of ceramides is linked to decreased insulin sensitivity of tissues. Conversely, activation of the insulin signaling pathway can downregulate ceramide synthesis. Elucidating the association between sphingolipid metabolism and insulin response during oral glucose te...

An 8‐year‐old Warmblood gelding presented with a history of progressive ataxia for 6 weeks. Intra‐ and intervertebral ratios measured from lateral radiographs of the cervical spine were within normal limits. Computed tomographic myelography of the cervical spine revealed focal compression of the dorsal and the ventral contrast column as well as a v...

Background. Insulin dysregulation (ID) is an equine endocrine disorder, which is often accompanied by obesity and various metabolic perturbations. The relationship between weight variations and fluctuations of the insulin response to oral glucose tests (OGT) as well as the metabolic impact of ID have been described previously. The present study see...

Background: Insulin dysregulation (ID) is a key risk factor for equine endocrinopathic laminitis, but in many cases ID can only be assessed accurately using dynamic tests. The identification of other biomarkers could provide an alternative or adjunct diagnostic method, to allow early intervention before laminitis develops. The present study charact...

Background Little is known about the implications of hyperinsulinemia on energy metabolism, and such knowledge might help understand the pathophysiology of insulin dysregulation. Objectives Describe differences in the metabolic response to an oral glucose test, depending on the magnitude of the insulin response. Animals Twelve Icelandic horses in...

Insulin Dysregulation (ID) encompasses different disorders like hyperinsulinemia and insulin resistance. The aim of this study was to determine if ID is associated with altered expression of key proteins of the insulin signaling cascade (ISC) in liver tissue under basal and/or stimulated conditions. Twelve Icelandic horses were subjected to an Oral...

Background: Insulin dysregulation (ID) goes along with lasting or transient hyperinsulinemia able to trigger equine laminitis, a painful and crippling foot condition. Promoting weight loss through dietary changes and physical activity is currently the main option to prevent this disease. This study aimed at describing the relationship between weig...

Hintergrund: Die Insulindysregulation bei Pferden geht oftmals mit einerperipheren Insulinresistenz einher, die mit einem Insulinstimulationstest (IST)diagnostiziert werden kann. Bei Verwendung von rekombinantem Human-insulin (RHI) sollte hierbei eine 50%ige Reduktion der initialen Glukosekon-zentration im Blut innerhalb von 30 Minuten erreicht wer...

Insulin dysregulated (ID) horses are prone to develop laminitis. Recent studies show promise that ID may be improved and laminitis may be prevented by the sodium-glucose linked cotransporter 2 (SGLT-2) inhibitor velagliflozin. The aim of the study was to investigate the metabolic responses and efficacy of velagliflozin treatment during the transiti...

Oral glycemic challenge tests are recommended for diagnosis of insulin dysregulation in equines. Several different protocols are used, but all of them have limitations in terms of palatability, ease of use in the field, not fully disclosed composition and/or region specific availability. The aim of the study was to evaluate new carbohydrate formula...

Assessment of disturbed insulin regulation with combined glucose-insulin test (CGIT) or oral glucose test (OGT) is essential in equids suffering from the EMS. Besides different testing protocols, quantification of equine insulin remains the final and main limiting step. Therefore, the aim of this study was to compare results supplied by an equine-o...

Sensory nerve conduction (SNC) threshold of the infraorbital nerve wasreported to be decreased in horses with idiopathic headshaking (IHS)with a stimulation threshold of≤5mA in comparison to healthy horses.In the current study, a prospective ongoing trial, horses were exam-ined using standardized diagnostic procedures to differentiate symp-tomatic...

Different diagnostic tests to determine the insulin sensitivity in horses are commonly used in veterinary practice. However, endocrine and metabolic responses provoked by physiological processes during the respective test procedures are not well described. In the present study, oral glucose tests (OGTs) and combined iv glucose-insulin tests (CGITs)...

Oral glucose tests (OGT) are currently recommended for diagnosis of insulin dysregulation (ID). As horses suffering from ID are prone to laminitis especially when exposed to high amounts of sugar it would be desirable to reduce the amount of diagnostic glucose. Furthermore, a reduced glucose amount enables various routes of application. Aim of this...

Abstract Background Insulin dysregulation in horses is a metabolic condition defined by high insulin concentrations in the blood and peripheral insulin resistance. This hyperinsulinemia is often associated with severe damage in the hooves, resulting in laminitis. However, we currently lack detailed information regarding the potential involvement of...

Background Insulin dysregulation (ID) with basal or postprandial hyperinsulinemia is one of the key findings in horses and ponies suffering from the equine metabolic syndrome (EMS). Assessment of ID can easily be performed in clinical settings by the use of oral glucose challenge tests. Oral glucose test (OGT) performed with 1 g/kg bodyweight (BW)...

Assessment of insulin dysregulation (ID) is essential to diagnose EMS. However, protocols for implementation of oral diagnostic test vary from glucose administration with the animals' feed to glucose administration via naso-gastric tubing. Manipulation-induced stress response during naso-gastric tubing is a common concern, resulting in missing owne...

The aim of the study was to analyze key proteins of the equine insulin signaling cascade and their extent of phosphorylation in biopsies from muscle tissue (MT), liver tissue (LT), and nuchal (NUAT), subcutaneous (SCAT) and retroperitoneal adipose tissues (RPAT). This was investigated under unstimulated (B1) and intravenously insulin stimulated (B2...

Background: Exact analysis of equine insulin in blood samples is the key element for assessing insulin resistance or insulin dysregulation in horses. However, previous studies indicated marked differences in insulin concentrations obtained from sample analyses with different immunoassays. Most assays used in veterinary medicine are originally desi...

Both deoxynivalenol (DON), zearalenone (ZEN), and their metabolites are known to modulate immune cells in various species whereby viability and proliferation are influenced. Such effects were rarely examined in horses. Therefore, one aim of the present study was to titrate the inhibitory concentrations of DON, 3-acetyl-DON (3AcDON), de-epoxy-DON (D...

Objective: In practice, determination of equine insulin sensitivity requires exact insulin quantification. However, previous studies indicated marked differences in values obtained from different immunoassays. Most assays used in veterinary medicine include antibodies directed against human insulin, although amino acid sequences between equine and...