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.

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.

Design, synthesis and preclinical evaluation of bio-conjugated amylinomimetic peptides as long-acting amylin receptor agonists.

Pramlintide is an equipotent amylin analogue that reduces food intake and body weight in obese subjects and has been clinically approved as an adjunctive therapy for the treatment of adult diabetic patients. However, due to its extremely short half-life in vivo, a regimen of multiple daily administrations is required for achieving clinical effectiveness. Herein is described the development of prototypical long-acting pramlintide bioconjugates, in which pramlintide's disulfide-linked macrocycle was replaced by a cyclic thioether motif. This modification enabled stable chemical conjugation to a half-life extending antibody. In contrast to pramlintide (t1/2 < 0.75 h), bioconjugates 35 and 38 have terminal half-lives of ∼2 days in mice and attain significant exposure levels that are maintained up to 7 days. Single dose subcutaneous administration of 35 in lean mice, given 18-20 h prior to oral acetaminophen (AAP) administration, significantly reduced gastric emptying (as determined by plasma AAP levels). In a separate study, similar administration of 35 in fasted lean mice effected a reduction in food intake for up to 48 h. These data are consistent with durable amylinomimetic responses and provide the basis for further development of such long-acting amylinomimetic conjugates for the potential treatment of obesity and associated pathologies.

Central control of energy balance by amylin and calcitonin receptor agonists and their potential for treatment of metabolic diseases.

The prevalence of obesity and associated comorbidities such as type 2 diabetes and cardiovascular disease is increasing globally. Body-weight loss reduces the risk of morbidity and mortality in obese individuals, and thus, pharmacotherapies that induce weight loss can be of great value in improving the health and well-being of people living with obesity. Treatment with amylin and calcitonin receptor agonists reduces food intake and induces weight loss in several animal models, and a number of companies have started clinical testing for peptide analogues in the treatment of obesity and/or type 2 diabetes. Studies predominantly performed in rodent models show that amylin and the dual amylin/calcitonin receptor agonist salmon calcitonin achieve their metabolic effects by engaging areas in the brain associated with regulating homeostatic energy balance. In particular, signalling via neuronal circuits in the caudal hindbrain and the hypothalamus is implicated in mediating effects on food intake and energy expenditure. We review the current literature investigating the interaction of amylin/calcitonin receptor agonists with neurocircuits that induce the observed metabolic effects. Moreover, the status of drug development of amylin and calcitonin receptor agonists for the treatment of metabolic diseases is summarized.

Dose Frequency Optimization of the Dual Amylin and Calcitonin Receptor Agonist KBP-088: Long-Lasting Improvement in Food Preference and Body Weight Loss.

Dual amylin and calcitonin receptor agonists (DACRAs) are novel candidates for treatment of type 2 diabetes and obesity because of their beneficial effects on body weight, blood glucose, insulin sensitivity, and food preference, at least short-term. DACRAs activate the receptors for a prolonged time period, resulting in metabolic effects superior to those of amylin. Because of the prolonged receptor activation, different dosing intervals and, hence, less frequent receptor activation might change the efficacy of DACRA treatment in terms of weight loss and food preference. In this study, we compared daily dosing to dosing every other day with the aim of understanding the optimal balance between efficacy and tolerability. Obese and lean male Sprague-Dawley rats were treated with the DACRA KBP-088, applying two different dosing intervals (1.5 nmol/kg once daily and 3 nmol/kg every other day) to assess the effect on body weight, food intake, glucose tolerance, and food preference when given the choice between chow (13% fat) and a high-fat diet (60% fat). Treatment with KBP-088 induced significant weight loss, reduction in adiposity, improvement in glucose control, and altered food preference toward food that is less calorie-dense. KBP-088 dosed every other day (3 nmol/kg) was superior to KBP-088 once daily (1.5 nmol/kg) in terms of weight loss and improvement of food preference. The beneficial effects were evident in both lean and obese rats. Hence, dosing KBP-088 every other day positively affects overall efficacy on metabolic parameters regardless of the lean/obese state, suggesting that less-frequent dosing with KBP-088 could be feasible. SIGNIFICANCE STATEMENT: Here, we show that food preference can be altered chronically toward choices that are less calorie-dense by pharmacological treatment. Further, pharmacological dosing regimens affect the efficacy differently, as dosing every other day improved body weight loss and alterations in food preference compared with daily dosing. This suggest that alterations of the dosing regimens could be feasible in the treatment of obesity.

Amylin and Calcitonin: Potential Therapeutic Strategies to Reduce Body Weight and Liver Fat.

The hormones amylin and calcitonin interact with receptors within the same family to exert their effects on the human organism. Calcitonin, derived from thyroid C cells, is known for its inhibitory effect on osteoclasts. Calcitonin of mammalian origin promotes insulin sensitivity, while the more potent calcitonin extracted from salmon additionally inhibits gastric emptying, promotes gallbladder relaxation, increases energy expenditure and induces satiety as well as weight loss. Amylin, derived from pancreatic beta cells, regulates plasma glucose by delaying gastric emptying after meal ingestion, and modulates glucagon secretion and central satiety signals in the brain. Thus, both hormones seem to have metabolic effects of relevance in the context of non-alcoholic fatty liver disease (NAFLD) and other metabolic diseases. In rats, studies with dual amylin and calcitonin receptor agonists have demonstrated robust body weight loss, improved glucose tolerance and a decreased deposition of fat in liver tissue beyond what is observed after a body weight loss. The translational aspects of these preclinical data currently remain unknown. Here, we describe the physiology, pathophysiology, and pharmacological effects of amylin and calcitonin and review preclinical and clinical findings alluding to the future potential of amylin and calcitonin-based drugs for the treatment of obesity and NAFLD.

A dual amylin and calcitonin receptor agonist inhibits pain behavior and reduces cartilage pathology in an osteoarthritis rat model.

OBJECTIVES: Pain and disability are the main clinical manifestations of osteoarthritis, for which only symptomatic therapies are available. Hence, there is a need for therapies that can simultaneously alter disease progression and provide pain relief. KBP is a dual amylin- and calcitonin-receptor agonist with antiresorptive and chondroprotective properties. In this study we investigated the effect of KBP in a rat model of osteoarthritis. METHODS: Medial meniscectomy (MNX) was performed in 39 rats, while 10 underwent sham surgery. Rats were treated with KBP and/or naproxen. Nociception was assessed by mechanical and cold allodynia, weight bearing asymmetry, and burrowing behavior. Blood samples were collected for biomarker measurements, and knees for histology. Cartilage histopathology was evaluated according to the advanced Osteoarthritis Research International (OARSI) score and KBPs in vitro antiresorptive effects were assessed using human osteoclasts cultured on bone. RESULTS: The MNX animals displayed an increased nociceptive behavior. Treatment with KBP attenuated the MNX-induced osteoarthritis-associated joint pain. The cartilage histopathology was significantly lower in rats treated with KBP than in MNX animals. Bone and cartilage degradation, assessed by CTX-I and CTX-II plasma levels, were decreased in all KBP-treated groups and KBP potently inhibited bone resorption in vitro. CONCLUSIONS: Our study demonstrates the effectiveness of KBP in ameliorating osteoarthritis-associated joint pain and in protecting the articular cartilage, suggesting KBP as a potential drug candidate for osteoarthritis.

Amylin Acts in the Lateral Dorsal Tegmental Nucleus to Regulate Energy Balance Through Gamma-Aminobutyric Acid Signaling.

BACKGROUND: The pancreatic- and brain-derived hormone amylin promotes negative energy balance and is receiving increasing attention as a promising obesity therapeutic. However, the neurobiological substrates mediating amylin's effects are not fully characterized. We postulated that amylin acts in the lateral dorsal tegmental nucleus (LDTg), an understudied neural processing hub for reward and homeostatic feeding signals. METHODS: We used immunohistochemical and quantitative polymerase chain reaction analyses to examine expression of the amylin receptor complex in rat LDTg tissue. Behavioral experiments were performed to examine the mechanisms underlying the hypophagic effects of amylin receptor activation in the LDTg. RESULTS: Immunohistochemical and quantitative polymerase chain reaction analyses show expression of the amylin receptor complex in the LDTg. Activation of LDTg amylin receptors by the agonist salmon calcitonin dose-dependently reduces body weight, food intake, and motivated feeding behaviors. Acute pharmacological studies and longer-term adeno-associated viral knockdown experiments indicate that LDTg amylin receptor signaling is physiologically and potentially preclinically relevant for energy balance control. Finally, immunohistochemical data indicate that LDTg amylin receptors are expressed on gamma-aminobutyric acidergic neurons, and behavioral results suggest that local gamma-aminobutyric acid receptor signaling mediates the hypophagia after LDTg amylin receptor activation. CONCLUSIONS: These findings identify the LDTg as a novel nucleus with therapeutic potential in mediating amylin's effects on energy balance through gamma-aminobutyric acid receptor signaling.

Intraperitoneal injection of the pancreatic peptide amylin potently reduces behavioral impairment and brain amyloid pathology in murine models of Alzheimer's disease.

Amylin, a pancreatic peptide, and amyloid-beta peptides (Aß), a major component of Alzheimer's disease (AD) brain, share similar ß-sheet secondary structures, but it is not known whether pancreatic amylin affects amyloid pathogenesis in the AD brain. Using AD mouse models, we investigated the effects of amylin and its clinical analog, pramlintide, on AD pathogenesis. Surprisingly, chronic intraperitoneal (i.p.) injection of AD animals with either amylin or pramlintide reduces the amyloid burden as well as lowers the concentrations of Aß in the brain. These treatments significantly improve their learning and memory assessed by two behavioral tests, Y maze and Morris water maze. Both amylin and pramlintide treatments increase the concentrations of Aß1-42 in cerebral spinal fluid (CSF). A single i.p. injection of either peptide also induces a surge of Aß in the serum, the magnitude of which is proportionate to the amount of Aß in brain tissue. One intracerebroventricular injection of amylin induces a more significant surge in serum Aß than one i.p. injection of the peptide. In 330 human plasma samples, a positive association between amylin and Aß1-42 as well as Aß1-40 is found only in patients with AD or amnestic mild cognitive impairment. As amylin readily crosses the blood-brain barrier, our study demonstrates that peripheral amylin's action on the central nervous system results in translocation of Aß from the brain into the CSF and blood that could be an explanation for a positive relationship between amylin and Aß in blood. As naturally occurring amylin may play a role in regulating Aß in brain, amylin class peptides may provide a new avenue for both treatment and diagnosis of AD.