Dapiglutide, a novel dual GLP-1 and GLP-2 receptor agonist, attenuates intestinal insufficiency in a murine model of short bowel

Isoquinoline small molecule ligands are agonists and probe-dependent allosteric modulators of the glucagon subfamily of GPCRs

Class B1 G protein-coupled receptors (GPCRs) are peptide hormone receptors and well validated therapeutic targets, however development of non-peptide drugs targeting this class of receptors is challenging. Recently, a series of isoquinoline-based derivates were reported in the patent literature as allosteric ligands for the glucagon receptor subfamily, and two compounds, LSN3451217 and LSN3556672, were used to facilitate structural studies with the glucagon-like peptide-1 receptor (GLP-1R) and glucose dependent insulinotropic peptide receptor (GIPR) bound to orthosteric agonists. Here we pharmacologically characterized stereoisomers of LSN3451217 and LSN3556672, across the class B1 GPCR family. This revealed LSN3556672 isomers are agonists for the glucagon receptor (GCGR), GLP-1R, GIPR and the calcitonin receptor (CTR), albeit the degree of agonism varied at each receptor. In contrast, LSN3451217 isomers were more selective agonists at the GLP-1R, with lower potency at the GCGR and CTR and no activity at the GIPR. All compounds also modulated peptide-mediated cyclic adenosine monophosphate (cAMP) signaling at the GIPR, and to a lesser extent the GLP-1R, in a probe-dependent manner, with modest positive allosteric modulation observed for some peptides, and negligible effects observed with other peptides. In contrast neutral or weak negative/positive allosteric modulation was observed with peptides assessed at the GCGR and CTR. This study expands our knowledge on class B1 GPCR allosteric modulation and may have implications for future structural and drug discovery efforts targeting the class B1 GPCR subfamily.

Emerging drugs for the treatment of short bowel syndrome

INTRODUCTION

SBS is a rare and disabling condition. The standard management is based on diet optimization with parenteral supplementation. In addition, glucagon-like peptide-2 (GLP-2)analogs, have shown promising results as disease-modifying therapies for SBS.

AREAS COVERED

Short bowel syndrome (SBS) is defined as a reduction in functional intestinal length to less than 200 cm, leading to intestinal failure (IF) leading to malnutrition and parenteral support dependency. This review discusses the current management of SBS-CIFpatients, the place of GLP-2 analog treatment in terms of efficacy, safety and availability, and the new perspectives opened by the use of enterohormones.

EXPERT OPINION

Clinical trials and real-world experience demonstrated that Teduglutide   reduces dependence on parenteral support and has a place in the management of patients with SBS-CIF.  The use of Teduglutide should be discussed in patients stabilized after resection and its introduction requires the advice of an expert center capable of assessing the benefit-risk ratio. The complex, individualized management of SBS-C IF requires theexpertise of a specialized IF center which a multidisciplinary approach. The arrival of new treatments will call for new therapeutic strategies, and the question of how to introduce and monitor them will represent a new therapeutic challenge.

Physiological functions of glucose transporter-2: From cell physiology to links with diabetes mellitus

Glucose is a sugar crucial for human health since it participates in many biochemical reactions. It produces adenosine 5'-triphosphate (ATP) and nucleosides through glucose metabolic and pentose phosphate pathways. These processes require many transporter proteins to assist in transferring glucose across cells, and the most notable ones are glucose transporter-2 (GLUT-2) and sodium/glucose cotransporter 1 (SGLT1). Glucose enters small intestinal epithelial cells from the intestinal lumen by crossing the brush boundary membrane via the SGLT1 cotransporter. It exits the cells by traversing the basolateral membrane through the activity of the GLUT-2 transporter, supplying energy throughout the body. Dysregulation of these glucose transporters is involved in the pathogenesis of several metabolic diseases, such as diabetes. Natural loss of GLUT-2 or its downregulation causes abnormal blood glucose concentrations in the body, such as fasting hypoglycemia and glucose tolerance. Therefore, understanding GLUT-2 physiology is necessary for exploring the mechanisms of diabetes and targeted treatment development. This article reviews how the apical GLUT-2 transporter maintains normal physiological functions of the human body and the adaptive changes this transporter produces under pathological conditions such as diabetes.

Advances in obesity pharmacotherapy; learning from metabolic surgery and beyond

Currently, metabolic surgery (MS) constitutes the most effective means for durable weight loss of clinically meaningful magnitude, type 2 diabetes remission and resolution of non-alcoholic steatohepatitis, as well as other obesity-related comorbidities. Accumulating evidence on the mechanisms through which MS exerts its actions has highlighted the altered secretion of hormonally active peptides of intestinal origin with biological actions crucial to energy metabolism as key drivers of MS clinical effects. The initial success of glucagon-like peptide-1 (GLP-1) receptor agonists regarding weight loss and metabolic amelioration have been followed by the development of unimolecular dual and triple polyagonists, additionally exploiting the effects of glucagon and/or glucose-dependent insulinotropic polypeptide (GIP) which achieves a magnitude of weight loss approximating that of common MS operations. Through the implementation of such therapies, the feasibility of a "medical bypass", namely the replication of the clinical effects of MS through non-surgical interventions may be foreseeable in the near future. Apart from weight loss, this approach ought to be put to the test also regarding other clinical outcomes, such as liver steatosis and steatohepatitis, cardiovascular disease, and overall prognosis, on which MS has a robustly demonstrated impact. Besides, a medical bypass as an alternative, salvage, or combination strategy to MS may promote precision medicine in obesity therapeutics.

Emerging uses of glucagon-like peptide 1 (GLP-1) receptor agonists following ileal resection: literature review and case examples

Following ileal resection, the combination of severe bile acid (BA) malabsorption, rapid small bowel transit and unrestricted upper gastrointestinal (GI) secretion results in severe diarrhoea that can prove refractory to pharmacological therapies. While established therapies, including BA sequestrants and antidiarrhoeal drugs seek to ameliorate symptoms, they do not target the underlying pathophysiological mechanisms in this patient group. Their use can also be limited by both intolerance and adverse effects. The novel use of glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) in these patients may allow restoration of the physiological negative feedback mechanisms lost in ileal resection and reduce diarrhoea by prolonging small bowel transit time, limiting upper GI secretions and perhaps by inhibiting hepatic BA synthesis. While recent evidence supports the use of GLP-1 RAs as a safe and effective therapy for bile acid diarrhoea (BAD), it remains uncertain whether those with severe BAD and subsequent short bowel syndrome secondary to extensive ileal resection will benefit. Here, we present three cases of severe diarrhoea secondary to extensive ileal resection in which the use of the GLP-1 RA, liraglutide, was well tolerated and resulted in an objective improvement in diarrhoeal symptoms. We further provide a narrative review of the emerging evidence base supporting the use of GLP therapies in this challenging condition.

An updated patent review of GLP-1 receptor agonists (2020-present)

INTRODUCTION

Type 2 diabetes (T2DM) and obesity present significant global health issues, requiring the development of long-lasting and highly effective pharmacotherapies. Although glucagon-like peptide-1 receptor agonists (GLP-1RAs) are commonly used for diabetes treatment, their potential for addressing obesity is still being explored.

AREAS COVERED

This review offers a comprehensive overview of recently published patents from January 2020 to July 2023, focusing on modified GLP-1RAs, small molecule GLP-1RAs, GLP-1 R-based multi-agonists, GLP-1RA-based fusion proteins, and combination therapies. The patents discussed pertain to the treatment and prevention of diabetes and obesity. Patent searches were conducted using the PATENTSCOPE database of the World Intellectual Property Organization, using the keywords GLP-1, GLP-1/GIP, GLP-1/GCG, and GLP-1/GCG/GIP.

EXPERT OPINION

In recent years, patents have emphasized two main goals for developing GLP-1RAs drugs: oral delivery and improved weight reduction effects. To address the growing demand for improved treatments, researchers have focused their efforts on developing GLP-1 R-based multi-agonists, orally administered GLP-1RAs, and combination therapies utilizing GLP-1RAs. These new approaches offer promising benefits, such as improved effectiveness by targeting multiple pathways and reduced side effects. Additionally, the development of new uses, oral forms, and long-lasting preparations will be crucial in shaping the future market potential of GLP-1 drugs.

Differential Responses of the GLP-1 and GLP-2 Receptors to N-Terminal Modification of a Dual Agonist

Class B1 G protein-coupled receptors (GPCRs), collectively, respond to a diverse repertoire of extracellular polypeptide agonists and transmit the encoded messages to cytosolic partners. To fulfill these tasks, these highly mobile receptors must interconvert among conformational states in response to agonists. We recently showed that conformational mobility in polypeptide agonists themselves plays a role in activation of one class B1 GPCR, the receptor for glucagon-like peptide-1 (GLP-1). Exchange between helical and nonhelical conformations near the N-termini of agonists bound to the GLP-1R was revealed to be critical for receptor activation. Here, we ask whether agonist conformational mobility plays a role in the activation of a related receptor, the GLP-2R. Using variants of the hormone GLP-2 and the designed clinical agonist glepaglutide (GLE), we find that the GLP-2R is quite tolerant of variations in α-helical propensity near the agonist N-terminus, which contrasts with signaling at the GLP-1R. A fully α-helical conformation of the bound agonist may be sufficient for GLP-2R signal transduction. GLE is a GLP-2R/GLP-1R dual agonist, and the GLE system therefore enables direct comparison of the responses of these two GPCRs to a single set of agonist variants. This comparison supports the conclusion that the GLP-1R and GLP-2R differ in their response to variations in helical propensity near the agonist N-terminus. The data offer a basis for development of new hormone analogues with distinctive and potentially useful activity profiles; for example, one of the GLE analogues is a potent agonist of the GLP-2R but also a potent antagonist of the GLP-1R, a novel form of polypharmacology.

Intestinal adaptation and rehabilitation

Massive intestinal resection is a regrettably necessary but life-saving intervention for progressive or fulminant necrotizing enterocolitis (NEC). However, the resultant short bowel syndrome (SBS) poses its own array of challenges and complications. Within hours of such an abrupt loss of intestinal length, the intestine begins to adapt. Our ability to understand this process of intestinal adaptation has proven critical in our ability to clinically treat the challenging problem of short bowel syndrome. This review first highlights key data relating to intestinal adaptation including structural and functional changes, biochemical regulation, and other factors affecting the magnitude of intestinal adaptation responses. We then focus on intestinal rehabilitation as it relates to strategies to enhance intestinal adaptation while meeting nutritional needs and preventing complications of parenteral nutrition.

Orally compensated short bowel patients are thin, potentially malnourished but rarely sarcopenic

BACKGROUND AND AIM

In short bowel syndrome, insufficient absorptive capacity of the remnant bowel may lead to metabolic and nutritional consequences including electrolyte disturbances, severe diarrhea and malnutrition. While intestinal failure requires parenteral nutrition, short bowel patients with intestinal insufficiency (SB/II) have achieved oral autonomy. The aim of this exploratory study was to assess the nutritional, muscular and functional status of orally compensated SB/II patients.

METHODS

28 orally compensated SB/II patients with a mean of 46 months after termination of parenteral nutrition and 56 age- and sex-matched healthy controls (HC) were compared regarding anthropometric parameters, body composition using bioelectrical impedance analysis, handgrip strength and gait speed, blood parameters as well as nutritional intake and physical activity using validated questionnaires. Malnutrition and sarcopenia were diagnosed according to the criteria of the GLIM or EWGSOP2.

RESULTS

SB/II patients had lower body mass index (BMI) and anthropometric parameters than HC but were within the normal weight range. The GLIM algorithm operationally diagnosed malnutrition in 39% (n = 11) of SB/II patients. Reduced skeletal muscle mass index and phase angle were rarely accompanied by a reduction of handgrip strength below cut-off values and the subsequent diagnosis of sarcopenia in SB/II patients (15%, n = 4). Compared to 11% of HC, 37% of SB/II patients had low physical activity level. Female SB/II patients had higher caloric and macronutrient intake. Caloric intake negatively correlated with body weight indicating compensatory hyperphagia in patients with lower body weight. Some of the SB/II patients showed signs of dehydration.

CONCLUSIONS

Orally compensated SB/II patients are thinner than HC but have mostly normal BMI. Malnutrition is frequently diagnosed but may be overestimated due to the underlying malabsorption and its interplay with hyperphagia. Muscle mass is often reduced but is rarely accompanied by functional impairment leading to sarcopenia diagnosis. Thus, SB/II patients long term after termination of parenteral support may be malnourished but usually do not develop sarcopenia.

Treatment of short bowel syndrome: Breaking the therapeutic ceiling?

Short bowel syndrome (SBS) is the most common cause of chronic intestinal failure, requiring home parenteral support (intravenous fluid, parenteral nutrition, or parenteral nutrition with intravenous fluid) to compensate for severe malabsorption. The loss of mucosal absorptive area after extensive intestinal resection is accompanied by an accelerated transit and hypersecretion. Changes in physiology and clinical outcomes differ between patients with SBS with or without the distal ileum and/or colon-in-continuity. This narrative review summarizes the treatments used in SBS, with a focus on novel approaches with intestinotrophic agents. During the early postoperative years, spontaneous adaptation occurs and can be induced or accelerated with conventional therapies, which include dietary and fluid modifications and antidiarrheal and antisecretory drugs. Based on the proadaptive role of enterohormones (eg, glucagon-like peptide [GLP]-2), analogues have been developed to allow enhanced or hyperadaptation after a period of stabilization. Teduglutide is the first GLP-2 analogue developed and commercialized with proadaptive effects resulting in reduced parenteral support needs; however, the potential for weaning of parenteral support is variable. Whether early treatment with enterohormones or accelerated hyperadaptation would further improve absorption and outcomes remains to be shown. Longer-acting GLP-2 analogues are currently being investigated. Encouraging reports with GLP-1 agonists require confirmation in randomized trials, and dual GLP-1 and GLP-2 analogues have yet to be clinically investigated. Future studies will prove whether the timing and/or combinations of different enterohormones will be able to break the ceiling of intestinal rehabilitation in SBS.

Designer GLP1 poly-agonist peptides in the management of diabesity

INTRODUCTION

To date, the 21^st Century has witnessed key developments in the management of diabesity (a conflation of obesity and Type 2 Diabetes Mellitus [T2D]), including Glucagon Like Peptide 1 (GLP1) receptor agonist therapies, and recently the 'designer' GLP1 Poly-agonist Peptides (GLP1PPs).

AREAS COVERED

A PubMed search of published data on the GLP1PP class of therapies was conducted. The gut-brain axis forms complex multi-directional interlinks that include autonomic nervous signaling, components of the gut microbiota (including metabolic by-products and gram-negative cell wall components [e.g. endotoxinaemia]), and incretin hormones that are secreted from the gut in response to the ingestion of nutrients. The development of dual-incretin agonist therapies includes combinations of the GLP1 peptide with Glucose-dependent Insulinotropic Polypeptide (GIP), Glucagon (Gcg), Cholecystokinin (CCK), Peptide YY (PYY), and Glucagon-Like Peptide 2 (GLP2). Triple incretin agonist therapies are also under development.

EXPERT OPINION

At the dawn of a new era in the therapeutic management of diabesity, the designer GLP1PP class holds great promise, with each novel combination building on a preexisting palimpsest of clinical data and insights. Future innovations of the GLP1PP class will likely enable medically induced weight loss and glycemic control in diabesity to rival or even out-perform those resulting from bariatric surgery.

Dysbiosis and reduced small intestinal function are required to induce intestinal insufficiency in mice

Extensive bowel resection can lead to short bowel syndrome and intestinal failure. Resection-induced dysbiosis may be related to the specific anatomic site of resection and influences the disease progression. Although patients with end-jejunostomy are at high risk for intestinal failure, preservation of the ileocecal valve and colon counteracts this risk. The present study investigated the role of the cecum in maintaining microbial homeostasis after different types of small bowel resection. Male C57BL6/J mice were anesthetized by intraperitoneal injection of ketamine-xylazine and received extended ileocecal resection (extended ICR), limited ileocecal resection (limited ICR), or mid-small bowel resection (SBR). Stool samples were collected before surgery and between postoperative days 2-7, for 16S rRNA gene sequencing. Only extended ICR, but neither limited ICR nor SBR, induced intestinal insufficiency. α-Diversity was reduced in both ICR variants but not after SBR. All resections resulted in an increase in Proteobacteria. Pathobionts, such as Clostridia, Shigella, and Enterococcus, increased after SBR while Muribaculaceae, Lactobacillus, and Lachnospiraceae decreased. Limited ICR resulted in an increase of members of the Clostridium sensu stricto group, Terrisporobacter and Enterococcus and a decrease of Muribaculaceae. The increase of Enterococcus was even more pronounced after extended ICR while Muribaculaceae and Akkermansia were dramatically reduced. Both ICR variants caused a decrease in steroid biosynthesis and glycosaminoglycan degradation-associated pathways, suggesting altered bile acid transformation and mucus utilization.NEW & NOTEWORTHY Resection-induced dysbiosis affects disease progression in patients with short bowel syndrome. Severe dysbiosis occurs after removal of the ileocecal valve, even in the absence of short bowel conditions, and is associated with the loss of Muribaculaceae and Akkermansia and an increase of Clostridium and Enterococcus. The preservation of the cecum should be considered in surgical therapy, and dysbiosis should be targeted based on its specific anatomical signature to improve postoperative bacterial colonization.

Glucagon-like peptide-2 analogues for Crohn’s disease patients with short bowel syndrome and intestinal failure

Short bowel syndrome (SBS) with intestinal failure (IF) is a rare but severe complication of Crohn’s disease (CD), which is the most frequent benign condition that leads to SBS after repeated surgical resections, even in the era of biologics and small molecules. Glucagon-like peptide-2 analogues have been deeply studied recently for the treatment of SBS-IF. These drugs have a significant intestinotrophic effect and the potential to reduce the chronic dependence of SBS-IF patients on parenteral support or nutrition. Teduglutide has been approved for the treatment of SBS-IF, and apraglutide is currently in clinical development. The use of these drugs was examined with a focus on their use in CD patients.

Disease-modifying therapies in short bowel syndrome

Short bowel syndrome (SBS) is the main cause of chronic intestinal failure (IF), defined as 'the reduction of gut function below the minimum necessary for the absorption of macronutrients and/or water and electrolytes, such that intravenous supplementation is required to maintain health and/or growth'. SBS is a rare disease requiring a multidisciplinary approach in specialized IF units. The aim of this review was to discuss the current pharmacological management of SBS-associated IF, since emerging treatments are currently modifying the natural evolution of these patients. Enterohormone therapy has become the first-choice treatment and may decrease the need for parenteral support and improve patients' quality of life.

The dual GLP-1 and GLP-2 receptor agonist dapiglutide promotes barrier function in murine short bowel

Short bowel syndrome can occur after extensive intestinal resection, causing intestinal insufficiency or intestinal failure, which requires long-term parenteral nutrition. Glucagon-like peptide-2 (GLP-2) pharmacotherapy is now clinically used to reduce the disease burden of intestinal failure. However, many patients still cannot be weaned off from parenteral nutrition completely. The novel dual GLP-1 and GLP-2 receptor agonist dapiglutide has previously been shown to be highly effective in a preclinical murine short bowel model. Here, we studied the effects of dapiglutide on intestinal epithelial barrier function. In the jejunum, dapiglutide increased claudin-7 expression and tightened the paracellular tight junction leak pathway. At the same time, dapiglutide promoted paracellular tight junction cation size selectivity in the jejunum. This was paralleled by extension of the cation selective tight junction proteins claudin-2 and claudin-10b and preserved claudin-15 expression and localization along the crypt-villus axis in the jejunum. In the colon, no barrier effects from dapiglutide were observed. In the colon, dapiglutide attenuated the short bowel-associated, compensatorily increased epithelial sodium channel activity, likely secondary, by improved volume status. Future studies are needed to address the intestinal adaptation of the colon.