Amylin Receptor Research Articles

Dual amylin and calcitonin receptor agonist treatment reduces biomarkers associated with kidney fibrosis in diabetic rats.

Dual amylin and calcitonin receptor agonists (DACRAs) are effective treatments for obesity and type 2 diabetes (T2D). They provide beneficial effects on body weight, glucose control, and insulin action. However, whether DACRAs protect against diabetes-related kidney damage remains unknown. We characterize the potential of long-acting DACRAs (KBP-A, Key Bioscience Peptide-A) as a treatment for T2D-related pathological alterations of the kidney extracellular matrix (ECM) in Zucker diabetic fatty rats (ZDF). We examined levels of endotrophin (profibrotic signaling molecule reflecting collagen type VI formation) and tumstatin (matrikine derived from collagen type IVα3) in serum and evaluated kidney morphology and collagen deposition in the kidneys. We included a study in obese Sprague-Dawley rats to further investigate the impact of KBP-A on ECM biomarkers. In ZDF vehicles, levels of endotrophin and tumstatin increased, suggesting disease progression along with an increase in blood glucose levels. These rats also displayed damage to their kidneys, which was evident from the presence of collagen formation in the medullary region of the kidney. Interestingly, KBP-A treatment attenuated these increases, resulting in significantly lower levels of endotrophin and tumstatin than the vehicle. Levels of endotrophin and tumstatin were unchanged in obese Sprague-Dawley rats, supporting the relation to diabetes-related kidney complications. Furthermore, KBP-A treatment normalized collagen deposition in the kidney while improving glucose control. These studies confirm the beneficial effects of DACRAs on biomarkers associated with kidney fibrosis. Moreover, these antifibrotic effects are likely associated with improved glucose control, highlighting KBP-A as a promising treatment of T2D and its related late complications.NEW & NOTEWORTHY These studies describe the beneficial effects of using a dual amylin and calcitonin receptor agonist (DACRA) for diabetes-related kidney complications. DACRA treatment reduced levels of serological biomarkers associated with kidney fibrosis. These reductions were further reflected by reduced collagen expression in diabetic kidneys. In general, these results validate the use of serological biomarkers while demonstrating the potential effect of DACRAs in treating diabetes-related long-term complications.

Structural insight into selectivity of amylin and calcitonin receptor agonists.

Amylin receptors (AMYRs), heterodimers of the calcitonin receptor (CTR) and one of three receptor activity-modifying proteins, are promising obesity targets. A hallmark of AMYR activation by Amy is the formation of a 'bypass' secondary structural motif (residues S19-P25). This study explored potential tuning of peptide selectivity through modification to residues 19-22, resulting in a selective AMYR agonist, San385, as well as nonselective dual amylin and calcitonin receptor agonists (DACRAs), with San45 being an exemplar. We determined the structure and dynamics of San385-bound AMY3R, and San45 bound to AMY3R or CTR. San45, via its conjugated lipid at position 21, was anchored at the edge of the receptor bundle, enabling a stable, alternative binding mode when bound to the CTR, in addition to the bypass mode of binding to AMY3R. Targeted lipid modification may provide a single intervention strategy for design of long-acting, nonselective, Amy-based DACRAs with potential anti-obesity effects.

Amylin Modulates a Ventral Tegmental Area–to–Medial Prefrontal Cortex Circuit to Suppress Food Intake and Impulsive Food-Directed Behavior

BackgroundA better understanding of the neural mechanisms regulating impaired satiety to palatable foods is essential to treat hyperphagia linked with obesity. The satiation hormone amylin signals centrally at multiple nuclei including the ventral tegmental area (VTA). VTA–to–medial prefrontal cortex (mPFC) projections encode food reward information to influence behaviors including impulsivity. We hypothesized that modulation of VTA-to-mPFC neurons underlies amylin-mediated decreases in palatable food-motivated behaviors. MethodsWe used a variety of pharmacological, behavioral, genetic, and viral approaches (n = 4–16/experiment) to investigate the anatomical and functional circuitry of amylin-controlled VTA-to-mPFC signaling in rats. ResultsTo first establish that VTA amylin receptor (calcitonin receptor) activation can modulate mPFC activity, we showed that intra-VTA amylin decreased food-evoked mPFC cFos. VTA amylin delivery also attenuated food-directed impulsive behavior, implicating VTA amylin signaling as a regulator of mPFC functions. Palatable food activates VTA dopamine and mPFC neurons. Accordingly, dopamine receptor agonism in the mPFC blocked the hypophagic effect of intra-VTA amylin, and VTA amylin injection reduced food-evoked phasic dopamine levels in the mPFC, supporting the idea that VTA calcitonin receptor activation decreases dopamine release in the mPFC. Surprisingly, calcitonin receptor expression was not found on VTA-to-mPFC projecting neurons but was instead found on GABAergic (gamma-aminobutyric acidergic) interneurons in the VTA that provide monosynaptic inputs to this pathway. Blocking intra-VTA GABA signaling, through GABA receptor antagonists and DREADD (designer receptor exclusively activated by designer drugs)–mediated GABAergic neuronal silencing, attenuated intra-VTA amylin-induced hypophagia. ConclusionsThese results indicate that VTA amylin signaling stimulates GABA-mediated inhibition of dopaminergic projections to the mPFC to mitigate impulsive consumption of palatable foods.

861-P: The Effect of Dual Amylin and Calcitonin Receptor Agonist Treatment on Spatial Memory in Rat Models of Metabolic Syndrome

Obesity and metabolic-related complications, especially insulin resistance, have been linked to cognitive dysfunction. Dual amylin and calcitonin receptor agonists (DACRAs) elicit beneficial effects on body weight, glucose control, and insulin action, making them novel candidates for treating obesity and related comorbidities. Whether DACRAs affect cognition has yet to be addressed. With these studies, we evaluated the effect of DACRA treatment on spatial learning and memory in rat models of metabolic syndrome. Spatial learning and spatial memory retention were evaluated by Morris Water Maze in ZDSD rats treated with KBP-336 (4.5 nmol/kg Q3D) for 7 months and ZSF1 rats treated with KBP-336 (4.5 nmol/kg Q3D) for 2 months. In the ZDSD study, rats performed 8 training trials with a hidden platform in a constant position and a 60 s probe without the platform. At the study end, rats performed a 60 s probe followed by 4 re-training trials and another probe. At study end of the ZSF1 study, rats performed 6 training trials with a hidden platform in a constant position followed by a 60 s probe without the platform. In both studies, KBP-336 treatment improved the overall metabolic status, including glucose control and insulin action. In ZDSD rats, KBP-336-treated rats spent more time and traveled longer distances in Whishaw's corridor than vehicle-treated rats during the probes at the study end. Together indicating a possible treatment improvement in spatial memory on KBP-336. In ZSF1 rats, KBP-336 treatment resulted in increased time spent in the platform quadrant and Whishaw's corridor, as well as increased distance, traveled in Whishaw's corridor during the probe. In both studies, the treatment did not affect the spatial learning evaluated as latency to reach the hidden platform during the training trials. Altogether, we found that the improved metabolic status obtained with KBP-336 treatment might have a beneficial effect on spatial memory in diabetic and obese rat models. Disclosure K.Mohamed: Employee; Nordic Bioscience. A.T.Larsen: Employee; Nordic Bioscience A/S. S.A.Melander: None. M.A.Karsdal: Speaker's Bureau; Pfizer Inc. K.Henriksen: Employee; Nordic Bioscience A/S, Stock/Shareholder; Nordic Bioscience A/S. Funding Danish Research Foundation; Innovation Fund Denmark; European Union’s Horizon 2020 Research and Innovation Program (814244)

840-P: Dual Amylin and Calcitonin Receptor Agonist Treatment Improves Blood Pressure and Glucose Control in ZSF1 Rats

Long-acting dual amylin and calcitonin receptor agonists (DACRAs) are novel candidates for the treatment of type 2 diabetes and obesity due to their beneficial effects on both body weight, glucose control and insulin action. However, whether DACRAs affect hypertension, and diabetes-related cardiovascular complications remain unknown. In this study, the cardiovascular protective effect of the DACRA KBP-336 was evaluated in obese Zucker diabetic fatty-Spontaneously hypertensive heart failure F1 hybrid (ZSF1) rats. Obese ZSF1 rats were treated for 60 days with the KBP-336 (4.5 nmol/kg Q3D) and treatment efficacy on glucose control and blood pressure measured by tail cuff was evaluated. Furthermore, serum biomarkers of cardiovascular complications were evaluated. KBP-336 treatment significantly lowered fasting blood glucose levels compared to vehicle (P<0.001). This was also illustrated in the HbA1c levels at study end, where KBP-336 resulted in significantly (P<0.001) lower levels than vehicle. Importantly, KBP-336 significantly reduced both systolic (AUC levels reduced by 13.3%, P<0.001) and diastolic (AUC levels reduced by 17.0%, P<0.001) blood pressure compared to vehicle without affecting the heart rate. Notably, the beneficial effects on both glucose control and blood pressure were obtained independent of weight loss as KBP-336 only resulted in a small and transient weight reduction. Furthermore, serum levels of the marker of cardiovascular disease, rPRO-C6 (collagen type VI formation marker) were 6.4% lower in KBP-336 treated rats compared to vehicle, supporting improvement in cardiovascular parameters. In summary, we show for the first time that KBP-336 benefits blood pressure in a metabolic rat model suffering from hypertension. In addition, KBP-336 improved glucose control independent of weight loss. These data highlight KBP-336 as a promising candidate for treating obesity and related comorbidities including type 2 diabetes and hypertension. Disclosure S.A.Melander: None. A.T.Larsen: Employee; Nordic Bioscience A/S. K.Mohamed: Employee; Nordic Bioscience. M.A.Karsdal: Speaker's Bureau; Pfizer Inc. K.Henriksen: Employee; Nordic Bioscience A/S, Stock/Shareholder; Nordic Bioscience A/S. Funding Danish Research Foundation; Innovation Fund Denmark; European Union’s Horizon 2020 Research and Innovation Program (814244)

211-OR: Dual Amylin and Calcitonin Receptor Agonists Increase Mitochondrial Respiratory Capacity in Adipose Tissues of Obese Rat

Dual amylin and calcitonin receptor agonists (DACRAs) are potential therapeutic candidates for treatment of obesity. Preclinical studies have shown favorable effects of DACRAs on appetite regulation contributing to a reduction in body weight. Interestingly, the DACRA-induced effects on weight loss are superior to the effects of a suppressed food intake, suggesting an effect on energy expenditure potentially by targeting the mitochondria. We investigated the effects of long-term treatment with a class of DACRAs, namely KBPs, on body weight, food intake and mitochondrial respiratory capacity (MRC) in Sprague-Dawley rats fed a high-fat diet and treated s.c. with KBPs for 8 weeks. Moreover, a pair-fed (PF) group was used to examine food intake-independent effects of KBPs on MRC. At study end, MRC was analyzed in perirenal (pAT) and inguinal (iAT) adipose tissue using high resolution respirometry. Expectedly, KBP treatment significantly reduced body weight compared to PF and vehicle. PF was successfully KBP-matched in terms of accumulated food intake and the food intake was significantly lower than that of vehicle-treated rats. Coupled and uncoupled MRC supported by complex I+II substrates and fatty acids were significantly greater in iAT and pAT after KBP treatment indicating effects on both carbohydrate and lipid metabolism. Additionally, an increased oligomycin-induced leak-respiration was found to be independent of food intake in iAT. Further analysis will shed light on whether these changes in MRC are a result of an increased mitochondrial content or of the respiratory capacity of each mitochondrion. In conclusion, treatment with KBPs in obese rats is associated with an increased MRC in pAT and iAT and elicits effects additional to those obtained by diet-induced weight loss. This highlights DACRAs’ potential as anti-obesity agents with possible benefits on energy expenditure as a contributing cause to the DACRA-induced weight loss. Disclosure E.A.Petersen: Employee; Nordic Bioscience A/S. I.Blom: None. S.A.Melander: None. M.A.Karsdal: Speaker's Bureau; Pfizer Inc. S.Larsen: None. K.Henriksen: Employee; Nordic Bioscience A/S, Stock/Shareholder; Nordic Bioscience A/S. A.T.Larsen: Employee; Nordic Bioscience A/S. Funding Innovation Fund Denmark

Treatment sequencing using the dual amylin and calcitonin receptor agonist KBP-336 and semaglutide results in durable weight loss

ObjectiveLong-acting dual amylin and calcitonin receptor agonists (DACRAs) hold great promise as potential treatments for obesity and its associated comorbidities. These agents have demonstrated beneficial effects on body weight, glucose control, and insulin action mirroring the effects observed with glucagon-like peptide-1 (GLP-1) agonist treatment. Strategies aimed at enhancing and prolonging treatment efficacy include treatment sequencing and combination therapy. Here, we sought to investigate the impact of switching between or combining treatment with the DACRA KBP-336 and the GLP-1 analog semaglutide in fed rats with obesity induced by a high-fat diet (HFD). MethodsTwo studies were performed in which HFD-induced obese Sprague Dawley rats were switched between treatment with KBP-336 (4.5 nmol/kg, Q3D) and semaglutide (50 nmol/kg, Q3D) or a combination of the two. Treatment efficacy on weight loss and food intake was evaluated, and glucose tolerance was assessed by oral glucose tolerance tests. ResultsKBP-336 and semaglutide monotherapy resulted in a similar reduction in body weight and food intake. Treatment sequencing resulted in continuous weight loss and all monotherapies resulted in similar weight loss independent of the treatment regimen (P < 0.001 compared to vehicle). The combination of KBP-336 and semaglutide significantly improved the weight loss compared to either monotherapy alone (P < 0.001), which was evident in the adiposity at the study end. All treatments improved glucose tolerance, with the KBP-effect on insulin sensitivity as the dominant response. ConclusionsThese findings highlight KBP-336 as a promising anti-obesity therapy both alone, in treatment sequencing, and in combination with semaglutide or other incretin-based therapies.

Dual amylin and calcitonin receptor agonist treatment improves insulin sensitivity and increases muscle-specific glucose uptake independent of weight loss

Dual amylin and calcitonin receptor agonists (DACRAs) are known to induce significant weight loss as well as improve glucose tolerance, glucose control, and insulin action in rats. However, to what extent DACRAs affect insulin sensitivity beyond that induced by weight loss and if DACRAs affect glucose turnover including tissue-specific glucose uptake is still unknown. Hyperinsulinemic glucose clamp studies were carried out in pre-diabetic ZDSD and diabetic ZDF rats treated with either the DACRA KBP or the long-acting DACRA KBP-A for 12 days. The glucose rate of disappearance was assessed using 3-3H glucose and tissue-specific glucose uptake was evaluated using 14C-2-deoxy-D-glucose (14C-2DG). In diabetic ZDF rats, KBP treatment significantly reduced fasting blood glucose and improved insulin sensitivity independent of weight loss. Furthermore, KBP increased the rate of glucose clearance, likely by increasing glucose storage, but without altering the endogenous glucose production. This was confirmed in pre-diabetic ZDSD rats. Direct assessment of tissue-specific glucose uptake showed, that both KBP and KBP-A significantly increased glucose uptake in muscles. In summary, KBP treatment significantly improved insulin sensitivity in diabetic rats and markedly increased glucose uptake in muscles. Importantly, in addition to their well-established weight loss potential, the KBPs have an insulin-sensitizing effect independent of weight loss, highlighting DACRAs as promising agents for the treatment of type 2 diabetes and obesity.

Amylin receptor agonism protects against metabolic side effects of acute olanzapine

Olanzapine is a second-generation antipsychotic (SGA) used in the treatment of schizophrenia and several on- and off-label conditions. While effective in reducing psychoses, acute olanzapine treatment causes rapid hyperglycemia, insulin resistance, and dyslipidemia and these perturbations are linked to an increased risk of developing cardiometabolic disease. Increases in glucagon are central to the metabolic side effects of olanzapine. Amylin receptor activation has been shown to reduce circulating glucagon but it is unclear if targeting amylin signaling would be an effective approach to lessen olanzapine-induced hyperglycemia alone or as an adjunct with other glucose lowering medications such as glucagon-like peptide-1 (GLP1) receptor agonist liraglutide. The purpose of this study was to 1) determine if treatment with recombinant amylin or the amylin receptor agonist pramlintide is sufficient to protect against acute olanzapine-induced impairments in glucose and lipid homeostasis and 2) if there are synergistic effects of combining pramlintide and liraglutide. We hypothesized that amylin and pramlintide would confer protection against olanzapine-induced perturbations in glucose homeostasis and that these effects would be additive with liraglutide. We found that pramlintide co-treatment lowered olanzapine-induced increases in glucagon:insulin. There was an additive effect of pramlintide and liraglutide in protecting against olanzapine-induced hyperglycemia and a synergistic effect on markers of dyslipidemia. Our findings provide evidence that pramlintide, while moderately protective against some aspects of olanzapine-induced metabolic dysfunction, can be used to enhance other interventions which protect against olanzapine-induced hyperglycemia. This research was supported by a Project Grant (PJT 159538) from the Canadian Institutes of Health Research to DCW. KDM was supported by a Postgraduate Scholarship from the Natural Sciences and Engineering Research Council (NSERC) of Canada. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Looking ahead to potential incretin combination therapies for nonalcoholic steatohepatitis in patients with diabetes

ABSTRACT Introduction There are no drugs approved by regulatory agencies for the treatment of nonalcoholic fatty liver disease (NAFLD); incretin combination therapies are being developed for treatment of type 2 diabetes and research has moved to test their usefulness in NAFLD. Areas covered We reviewed the literature on the effectiveness of dual and triple peptides combining receptor agonists of the glucagon-like peptide 1, the glucose-dependent insulinotropic peptide, and glucagon to treat NAFLD and its associated metabolic diseases, and/or the cardiovascular risk intimately connected with the cluster of the metabolic syndrome. Other combination peptides involved the glucagon-like peptide 2 receptor, the fibroblast growth factor 21, the cholecystokinin receptor 2, and the amylin receptor. Expert opinion Both dual and triple agonists are promising, based on animal, pharmacokinetic and proof-of concept studies, showing effectiveness both in the presence and the absence of diabetes on a few validated surrogate NAFLD biomarkers, but the majority of studies are still in progress. Considering the long natural history of NAFLD, final proof of their efficacy on primary clinical liver outcomes might be also derived from the analysis of large databases of National Healthcare Systems or Insurance companies, when used in diabetes for improving glycemic control, after careful propensity-score matching.

Calcitonin receptors in GtoPdb v.2023.1

This receptor family comprises a group of receptors for the calcitonin/CGRP family of peptides. The calcitonin (CT), amylin (AMY), calcitonin gene-related peptide (CGRP) and adrenomedullin (AM) receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on CGRP, AM, AMY, and CT receptors [131, 74, 71]) are generated by the genes CALCR (which codes for the CT receptor, CTR) and CALCRL (which codes for the calcitonin receptor-like receptor, CLR, previously known as CRLR). Their function and pharmacology are altered in the presence of RAMPs (receptor activity-modifying proteins), which are single TM domain proteins of ca. 150 amino acids, identified as a family of three members; RAMP1, RAMP2 and RAMP3. There are splice variants of the CTR; these in turn produce variants of AMY receptors [131], some of which can be potently activated by CGRP. The endogenous agonists are the peptides calcitonin, α-CGRP (formerly known as CGRP-I), β-CGRP (formerly known as CGRP-II), amylin (occasionally called islet-amyloid polypeptide, diabetes-associated polypeptide), adrenomedullin and adrenomedullin 2/intermedin. There are species differences in peptide sequences, particularly for the CTs. CTR-stimulating peptide (CRSP) is another member of the family with selectivity for the CTR but it is not expressed in humans [93]. CLR (calcitonin receptor-like receptor) by itself binds no known endogenous ligand, but in the presence of RAMPs it gives receptors for CGRP, adrenomedullin and adrenomedullin 2/intermedin. There are several approved drugs that target this receptor family, such as pramlintide, erenumab, and the "gepant" class of CGRP receptor antagonists. There are also species differences in agonist pharmacology; for example, CGRP displays potent activity at multiple rat and mouse receptors [58, 15]. The summary table only reflects human receptor pharmacology.

Neuroprotective Mechanisms of Amylin Receptor Activation, Not Antagonism, in the APP/PS1 Mouse Model of Alzheimer's Disease.

Amylin, a pancreatic amyloid peptide involved in energy homeostasis, is increasingly studied in the context of Alzheimer's disease (AD) etiology. To date, conflicting pathogenic and neuroprotective roles for this peptide and its analogs for AD pathogenesis have been described. Whether the benefits of amylin are associated with peripheral improvement of metabolic tone/function or directly through the activation of central amylin receptors is also unknown and downstream signaling mechanisms of amylin receptors are major objectives of this study. To address these questions more directly we delivered the amylin analog pramlintide systemically (IP), at previously identified therapeutic doses, while centrally (ICV) inhibiting the receptor using an amylin receptor antagonist (AC187), at doses known to impact CNS function. Here we show that pramlintide improved cognitive function independently of CNS receptor activation and provide transcriptomic data that highlights potential mechanisms. Furthermore, we show than inhibition of the amylin receptor increased amyloid-beta pathology in female APP/PS1 mice, an effect than was mitigated by peripheral delivery of pramlintide. Through transcriptomic analysis of pramlintide therapy in AD-modeled mice we found sexual dimorphic modulation of neuroprotective mechanisms: oxidative stress protection in females and membrane stability and reduced neuronal excitability markers in males. These data suggest an uncoupling of functional and pathology-related events and highlighting a more complex receptor system and pharmacological relationship that must be carefully studied to clarify the role of amylin in CNS function and AD.

Insight into the role of the gut-brain axis in alcohol-related responses: Emphasis on GLP-1, amylin, and ghrelin.

Alcohol use disorder (AUD) contributes substantially to global morbidity and mortality. Given the heterogenicity of this brain disease, available pharmacological treatments only display efficacy in sub-set of individuals. The need for additional treatment options is thus substantial and is the goal of preclinical studies unraveling neurobiological mechanisms underlying AUD. Although these neurobiological processes are complex and numerous, one system gaining recent attention is the gut-brain axis. Peptides of the gut-brain axis include anorexigenic peptide like glucagon-like peptide-1 (GLP-1) and amylin as well as the orexigenic peptide ghrelin. In animal models, agonists of the GLP-1 or amylin receptor and ghrelin receptor (GHSR) antagonists reduce alcohol drinking, relapse drinking, and alcohol-seeking. Moreover, these three gut-brain peptides modulate alcohol-related responses (behavioral and neurochemical) in rodents, suggesting that the alcohol reduction may involve a suppression of alcohol's rewarding properties. Brain areas participating in the ability of these gut-brain peptides to reduce alcohol-mediated behaviors/neurochemistry involve those important for reward. Human studies support these preclinical studies as polymorphisms of the genes encoding for GLP-1 receptor or the ghrelin pathway are associated with AUD. Moreover, a GLP-1 receptor agonist decreases alcohol drinking in overweight patients with AUD and an inverse GHSR agonist reduces alcohol craving. Although preclinical and clinical studies reveal an interaction between the gut-brain axis and AUD, additional studies should explore this in more detail.

Improved metabolic efficacy of a dual amylin and calcitonin receptor agonist when combined with semaglutide or empagliflozin

Pharmacotherapies for obesity and type 2 diabetes (T2D) are thought to bridge the gap between lifestyle modification and the weight loss obtained with bariatric surgery. Although the effect of monotherapies, namely amylin and glucagon-like peptide-1 receptor (GLP-1R) agonists, has shown great potential, combination therapy is now becoming a strategy to optimize efficacy for weight management while minimizing adverse effects. This study investigated a dual amylin and calcitonin receptor agonist (DACRA); KBP-066A in combination with the GLP-1R agonist semaglutide or the sodium-glucose co transporter-2 inhibitor (SGLT2i) empagliflozin for anti-obesity and anti-diabetic treatment. The effect of KBP-066A, semaglutide, and empagliflozin alone and in combination was studied with respect to their impact on body weight, food intake, and glucose metabolism in high-fat diet (HFD) and Zucker diabetic fatty (fa/fa) (ZDF) rats. Treatment with KBP-066A and semaglutide lowered body weight by 13% and 9.7%.In contrast, a combination of both KBP-066A + semaglutide reduced body weight by 21% in HFD rats demonstrating superiority compared to monotherapies alone. A combination of KBP-066A with semaglutide or empagliflozin significantly lowered fasting blood glucose, and HbA1C (%) levels in ZDF rats. The complementary action by KBP-066A to GLP-1R agonist and SGLT2i on BW, food intake and glucose control endorsed the potential of DACRAs as an add-on therapy to therapeutic options for T2D and obesity.

Does receptor balance matter? – Comparing the efficacies of the dual amylin and calcitonin receptor agonists cagrilintide and KBP-336 on metabolic parameters in preclinical models

Cagrilintide is a novel long-acting amylin receptor agonist, which has shown a potent induction of weight loss. Interestingly, cagrilintide is a Dual Amylin and Calcitonin Receptor Agonist (DACRA) derived from an amylin backbone. Another class of long-acting DACRAs exists, namely the KBPs. These are salmon calcitonin-based and have shown preclinical potential; however, how and if they differentiate from amylin-derived molecules remain to be studied. Here, we compare cagrilintide to the DACRA KBP-336 with respect to receptor activation balance in vitro and using metabolic in vivo models. Peptide potencies were assessed using receptor-specific assays in vitro and in vivo. In vivo efficacies on body weight and glucose homeostasis were investigated head-to-head in high-fat diet (HFD) fed obese and T2D (ZDF) rat models. Both peptides activate the amylin and the calcitonin receptor in vitro and in vivo, with KBP-336 being more potent, and showing a CTR bias. KBP-336 and cagrilintide induced a potent and dose-dependent weight loss in HFD rats, with the highest dose of KBP-336 being superior to cagrilintide. In diabetic ZDF rats, DACRA treatment improved fasting blood glucose, HbA1c levels, and insulin action, with KBP-336 being superior to cagrilintide in improving glucose control. In summary, both KBP-336 and cagrilintide are DACRAs, however with KBP-336 being biased towards the CTR resulting in a different receptor activation balance. Interestingly, KBP-336 showed superior long-term efficacy on both weight loss and glucose control, supporting relevance of the receptor balance, and highlighting KBP-336 as a promising agent for the treatment of obesity and T2D.

Amylin Pharmacology in Alzheimer's Disease Pathogenesis and Treatment.

The metabolic peptide hormone amylin, in concert with other metabolic peptides like insulin and leptin, has an important role in metabolic homeostasis and has been intimately linked to Alzheimer's disease (AD). Interestingly, this pancreatic amyloid peptide is known to self-aggregate much like amyloid-beta and has been reported to be a source of pathogenesis in both Type II diabetes mellitus (T2DM) and Alzheimer's disease. The traditional "gain of toxic function" properties assigned to amyloid proteins are, however, contrasted by several reports highlighting neuroprotective effects of amylin and a recombinant analog, pramlintide, in the context of these two diseases. This suggests that pharmacological therapies aimed at modulating the amylin receptor may be therapeutically beneficial for AD development, as they already are for T2DMM. However, the nature of amylin receptor signaling is highly complex and not well studied in the context of CNS function. Therefore, to begin to address this pharmacological paradox in amylin research, the goal of this review is to summarize the current research on amylin signaling and CNS functions and critically address the paradoxical nature of this hormone's signaling in the context of AD pathogenesis.

The Impact of Exposure Profile on the Efficacy of Dual Amylin and Calcitonin Receptor Agonist Therapy.

Background: Dual Amylin and Calcitonin Receptor Agonists (DACRAs) are treatment candidates for obesity and type 2 diabetes. Recently, a once-weekly DACRA (KBP-A) showed promise, potentially due to its different exposure profile compared to daily DACRA (KBP). Parathyroid hormone, a G-protein-coupled receptor (GPCR) class B agonist, is an example of the exposure profile being critical to the effect. Since KBP and KBP-A also activate GPCR class B, we compared the effects of injection to continuous infusion of short-acting KBP and long-acting KBP-A in obese and diabetic rats to shed light on the role of exposure profiles. Methods: To explore the metabolic benefits of dose optimization, the following dosing profiles were compared in High Fat Diet (HFD)-fed Sprague–Dawley rats and diabetic Zucker Diabetic Fatty (ZDF) rats: (1) KBP dosed once-daily by injection or by continuous infusion in HFD and ZDF rats; (2) KBP injected once-daily and KBP-A injected once every 3rd day (Q3D) in HFD rats; (3) KBP-A injected Q3D or by infusion in ZDF rats. Results: KBP and KBP-A, delivered by either injection or infusion, resulted in similar weight and food intake reductions in HFD rats. In ZDF rats, injection of KBP improved glucose control significantly compared to infusion, while delivery of KBP-A by injection and continuous infusion was comparable in terms of glucose control. Conclusion: different dosing profiles of KBP and KBP-A had no impact on metabolic benefits in HFD rats. In diabetic ZDF rats, KBP by injection instead of infusion was superior, while for KBP-A the effects were similar.

THERAPY OF ENDOCRINE DISEASE: Amylin and calcitonin - physiology and pharmacology.

Type 2 diabetes is a common manifestation of metabolic dysfunction due to obesity and constitutes a major burden for modern health care systems, in concert with the alarming rise in obesity worldwide. In recent years, several successful pharmacotherapies improving glucose metabolism have emerged and some of these also promote weight loss, thus, ameliorating insulin resistance. However, the progressive nature of type 2 diabetes is not halted by these new anti-diabetic pharmacotherapies. Therefore, novel therapies promoting weight loss further and delaying diabetes progression are needed. Amylin, a beta cell hormone, has satiating properties and also delays gastric emptying and inhibits postprandial glucagon secretion with the net result of reducing postprandial glucose excursions. Amylin acts through the six amylin receptors, which share the core component with the calcitonin receptor. Calcitonin, derived from thyroid C cells, is best known for its role in humane calcium metabolism, where it inhibits osteoclasts and reduces circulating calcium. However, calcitonin, particularly of salmon origin, has also been shown to affect insulin sensitivity, reduce the gastric emptying rate and promote satiation. Preclinical trials with agents targeting the calcitonin receptor and the amylin receptors, show improvements in several parameters of glucose metabolism including insulin sensitivity and some of these agents are currently undergoing clinical trials. Here, we review the physiological and pharmacological effects of amylin and calcitonin and discuss the future potential of amylin and calcitonin-based treatments for patients with type 2 diabetes and obesity.

823-P: The Long-Acting Dual Amylin and Calcitonin Receptor Agonist KBP Has Increased Efficacy on Weight Loss and Glucose Control Compared with Cagrilintide in Obese and Diabetic Rats

Long-acting dual amylin and calcitonin receptor agonists (DACRAs) are novel candidates for treatment of type 2 diabetes (T2D) and obesity due to their beneficial effects on both body weight, glucose control and insulin action. Cagrilintide, which is currently in clinical trials, has shown promising effects on weight loss. In this study we compared a new long-acting DACRA (KBP) to cagrilintide in pre-clinical models of obesity and T2D. In vitro potencies were assessed using receptor assays. In vivo efficacies were investigated head-to-head in high fat diet (HFD) fed obese and T2D (ZDF) rat models. In vitro data showed that both peptides active both the amylin and the calcitonin receptor, with KBP being more potent on both receptors. This was further confirmed in vivo by assessment of acute effects on food intake and CTX suppression. KBP (1.5, 4.5 and 13.5 nmol/kg) and cagrilintide (10, 30 and 100 nmol/kg) induced a potent and dose-dependent weight loss in HFD rats, with the highest dose of KBP being superior to cagrilintide. In diabetic ZDF rats, DACRA treatment improved glucose control and preserved plasma insulin compared to vehicle. Interestingly, despite similar levels of plasma insulin, KBP treatment was superior to cagrilintide in improving glucose control. This was further reflected in the HbA1c levels at study end, where KBP treatment resulted in significantly lower levels compared to cagrilintide. In summary, both DACRAs induced weight loss and improved glucose tolerance, insulin action as well as glucose control. However, KBP treatment results in superior efficacy on both weight loss and glucose control. These findings highlight KBP as a promising once-weekly agent for treatment of obesity and T2D. Disclosure A.T.Larsen: Employee; Nordic Bioscience. N.Sonne: None. K.Mohamed: None. E.Bredtoft: None. F.Andersen: None. M.A.Karsdal: Employee; Nordic Bioscience A/S, Nordic Bioscience A/S, Nordic Bioscience A/S. K.Henriksen: Employee; Nordic Bioscience A/S, Stock/Shareholder; Nordic Bioscience A/S.

824-P: Dual Amylin and Calcitonin Receptor Agonists Improve Insulin Sensitivity and Increase Tissue-Specific Glucose Uptake Independent of Weight Loss

Dual amylin and calcitonin receptor agonists (DACRAs) are known to induce a significant weight loss and improve glucose tolerance and glucose control in rats. However, it is unknown if DACRAs has an insulin sensitizing effect beyond that induced by weight loss and if DACRAs affect tissue specific glucose uptake. Additionally, clamp studies with DACRAs have not previously been performed in diabetic rats. Pre-diabetic ZDSD and diabetic ZDF rats were treated with the DACRA KBP-088 (1.5 nmol//kg, s.c.) for 12 days, and a hyperinsulinemic clamp was conducted on day 13, 24 h post-dosing. In ZDSD rats a hyperinsulinemic euglycemic clamp was carried out, while a hyperinsulinemic isoglycemic clamp was carried out in ZDF rats. In addition, specific glucose uptake was assessed during a hyperinsulinemic isoglycemic clamp in ZDF rats. In ZDSD rats, KBP-088 treatment resulted in a significant reduction in body weight and fasting blood glucose, and improved insulin sensitivity by increasing the glucose infusion rate (GIR) (vehicle: 8.6, KBP-088: 12 mg glucose/kg/min) . In ZDF rats, KBP-088 significantly reduced fasting blood glucose and improved insulin sensitivity (GIR, vehicle: 1.5, KBP-088: 16.5 mg glucose/kg/min) , independent on weight loss. In both studies, KBP-088 increased the rate of glucose clearance, likely be increasing glucose storage, but without altering the endogenous glucose production. Direct assessment of tissue specific glucose uptake showed, that KBP-088 significantly increased glucose uptake in both muscles and adipose tissues when compared to vehicle. In summary, KBP-088 significantly improved insulin sensitivity in both pre-diabetic and diabetic rats and markedly increased tissue specific glucose uptake. Importantly, KBP-088 has an insulin sensitizing effect independent of weight loss, highlighting DACRAs as promising agents for treatment of diabetes. Disclosure A.T.Larsen: Employee; Nordic Bioscience. N.Sonne: None. E.Bredtoft: None. M.A.Karsdal: Employee; Nordic Bioscience A/S, Nordic Bioscience A/S, Nordic Bioscience A/S. K.Henriksen: Employee; Nordic Bioscience A/S, Stock/Shareholder; Nordic Bioscience A/S.