Searchable abstracts of presentations at key conferences in endocrinology
Endocrine Abstracts (2023) 97 003 | DOI: 10.1530/endoabs.97.003

BES2023 BES 2023 Section (29 abstracts)

Low-dose anti-thymocyte globulin in combination with verapamil reverses hyperglycaemia in newly diagnosed diabetic NOD mice

Martens P. J. 1 , Viaene M. 1 , Ellis D. 1 , Geukens N. 2 , Mathieu C 1 & Gysemans C. 1


1Clinical and Experimental Endocrinology (CEE), Campus Gasthuisberg O&N1, KU Leuven, Leuven, Belgium; 2PharmAbs, Campus Gasthuisberg O&N2, KU Leuven, Leuven, Belgium


Background: To arrest the immune-mediated destruction of the insulin-producing pancreatic beta cells in type 1 diabetes (T1D), interventional studies have predominantly focussed on two distinct approaches: arresting the ongoing immune response or protecting the pancreatic beta cells. Recently, both approaches using respectively low-dose anti-thymocyte globulin (ATG), an immune-depleting agent, and verapamil, a calcium channel blocker with beta cell protective and immune targeting properties, have demonstrated promising effects as single agents at T1D onset. However, the primary challenge remains the achievement of a durable response, primarily attributable to the highly immunogenic response and the restricted availability of functional beta cells at symptom onset. Consequently, integrating general immunomodulatory with beta cell supportive therapy represents a promising approach to achieve superior and long-lasting outcomes, particularly when initiated at symptom onset.

Methods: We combined low-dose murine (m)ATG (250 µg per day on day 0 and 3; i.v.) with continuous administration of verapamil (1 mg/ml in drinking water) to study their efficacy in newly diagnosed diabetic non-obese diabetic (NOD) mice.

Results: Low-dose mATG reversed T1D in 39% of mice (n=7/18) 7 days after therapy start, but the effect waned to 22% of mice by 8-weeks follow-up. Verapamil stably reversed disease in 20% of mice (n=3/15). However, combining low-dose mATG with verapamil induced durable disease remission in 45% of mice (n=9/20; P<0.0001 vs. control). Especially in mice with mild hyperglycaemia (<350 mg/dl) at disease onset combination reversed 75% (n=6/8) of mice compared to 33% in either low-dose mATG (n=3/9 mice; P<0.05) or verapamil (n=2/6 mice; P<0.05). While combination therapy resulted in a more pronounced disease reversal, this was not mirrored in the levels of pancreatic insulin content. However, preservation of beta cell function, as indicated by C-peptide levels, was observed only in combination-treated mice. Regarding pancreas inflammation, only combination therapy reduced insulitis severity. Mechanistically, either low-dose mATG-treated group induced lymphocyte depletion (69% reduction vs. control) 3 days after therapy start, recovering by day 14. Flow cytometry analysis revealed a decreased percentage of CD8+ T cells in the blood of either low-dose mATG-treated group at day 3, followed by a recovery of effector memory (EM) CD44highCD62L-CD8+ T cells by day 14. Moreover, low-dose mATG was associated with an increased frequency of FoxP3+(CD25+) regulatory T cells (Tregs) in the blood and pancreatic-draining lymph nodes (PLN) by day 14. Interestingly, only combination therapy had an increased ratio of Tregs-to-activated CD44highCD8+ T cells in PLN.

Conclusion: This is the first study to demonstrate that a short course of lowdose mATG in combination with verapamil protects the beta cells and mechanistically induces a transient imbalance in the frequency of immune cells favouring Tregs. This has to potential to establish enduring immune tolerance and confer sustained T1D remission in future clinical trials.

Article tools

My recent searches

No recent searches.