Search Results (2,142)

The insulin-like growth factor (IGF) system regulates implantation, placental development, and angiogenesis in eutherian mammals. However, little is known about the changes in this system in equine placenta (chorioallantois; CA) and the endometrium (EN) during pregnancy, or the relationship to vascular endothelial growth factor (VEGF) expression. The current study investigated the expression of the IGF system components, namely the ligands (IGF1 and IGF2), their receptors (IGF1R, IGF2R, and INSR), and their binding proteins (IGFBPs and IGF2BPs) in equine CA at 45 days, 4, 6, 10, and 11 months of gestational age (GA) and immediately postpartum (PP), and in equine EN at 4, 6, 10, and 11 months GA. IGF1 immunolocalization and serum concentrations were also evaluated across gestation. IGF1 mRNA expression in CA increased from day 45 to peak at 6 months and then gradually declined to reach a nadir in PP samples. This profile correlated positively with the VEGF expression profile (r = 0.62, p = 0.001). In contrast, IGF2 expression in CA was not correlated with VEGF (p = 0.14). Interestingly, IGF2 mRNA was more abundant in equine CA than IGF1 (p < 0.05) throughout gestation. Among the IGFBPs investigated in CA, the expression of IGFBP2 and IGF2BP2 was highly abundant (p < 0.05) at day 45 compared to other GAs. Conversely, mRNA expression for IGFBP3 and IGFBP5 was more abundant (p < 0.05) in PP than at all investigated GAs. Immunohistochemistry revealed that IGF1 is localized in the equine chorionic epithelium (cytoplasm and nucleus). IGF1 serum concentrations peaked at 9 months and declined to their lowest levels PP. In conclusion, this study demonstrates a positive correlation between IGF1 and VEGF expression in equine CA during gestation, suggesting that the IGF system plays a crucial role in placental angiogenesis by regulating VEGF. Full article

Background: Thyroid eye disease (TED) is a rare autoimmune orbital disorder predominantly associated with Graves’ disease. It is characterized by orbital inflammation, tissue remodeling, and potential visual morbidity. Conventional therapies, particularly systemic glucocorticoids, offer only partial symptomatic relief, failing to reverse chronic structural changes such as proptosis and diplopia, and are associated with substantial adverse effects. This review aims to synthesize recent developments in understandings of TED pathogenesis and to critically evaluate emerging therapeutic strategies. Methods: A systematic literature review was conducted using MEDLINE, Embase, and international clinical trial registries focusing on pivotal clinical trials and investigational therapies targeting core molecular pathways involved in TED. Results: Current evidence suggests that TED pathogenesis is primarily driven by the autoimmune activation of orbital fibroblasts (OFs) through thyrotropin receptor (TSH-R) and insulin-like growth factor-1 receptor (IGF-1R) signaling. Teprotumumab, a monoclonal IGF-1R inhibitor and the first therapy approved by the U.S. Food and Drug Administration for TED, has demonstrated substantial clinical benefit, including improvements in proptosis, diplopia, and quality of life. However, concerns remain regarding relapse rates and treatment-associated adverse events, particularly hearing impairment. Investigational therapies, including next-generation IGF-1R inhibitors, small-molecule antagonists, TSH-R inhibitors, neonatal Fc receptor (FcRn) blockers, cytokine-targeting agents, and gene-based interventions, are under development. These novel approaches aim to address both inflammatory and fibrotic components of TED. Conclusions: Teprotumumab has changed TED management but sustained control and toxicity reduction remain challenges. Future therapies should focus on targeted, mechanism-based, personalized approaches to improve long-term outcomes and patient quality of life. Full article

The kallikrein–kinin system and its B1 and B2 receptors are key regulators in metabolic disorders such as obesity, diabetes, and insulin resistance. Obesity, a chronic and multifactorial condition often associated with comorbidities like type 2 diabetes and dyslipidemia, remains poorly understood at the metabolic level. The kinin B2 receptor (B2R) is involved in blood pressure regulation and glucose metabolism, promoting glucose uptake in skeletal muscle via bradykinin. Studies in B2R-KO mice demonstrate that the absence of this receptor predisposes animals to glucose intolerance under a high-fat diet and impairs adaptive thermogenesis, indicating a protective role for B2R in metabolic homeostasis and insulin sensitivity. In contrast, the kinin B1 receptor (B1R) is inducible under pathological conditions and is activated by kinin metabolites. Mouse models lacking B1R exhibit improved metabolic profiles, including protection against high-fat diet-induced obesity and insulin resistance, enhanced energy expenditure, and increased leptin sensitivity. B1R inactivation in adipocytes enhances insulin responsiveness and glucose tolerance, supporting its role in the development of insulin resistance. Moreover, B1R deficiency improves energy metabolism and thermogenic responses to adrenergic and cold stimuli, promoting the activation of brown adipose tissue and the browning of white adipose tissue. Collectively, these findings suggest that B1R and B2R represent promising therapeutic targets for the treatment of metabolic disorders. Full article

Background and Objectives: Metabolic dysfunction-associated steatotic liver disease (MASLD) is a progressive liver disorder associated with metabolic risk factors such as obesity, type 2 diabetes, and cardiovascular disease. If left untreated, the accumulation of excess hepatic fat can lead to inflammation, fibrosis, cirrhosis, hepatocellular carcinoma, and ultimately liver failure. Capsaicin (CAP), the primary pungent compound in chili peppers, has previously been shown to prevent weight gain in high-fat diet (HFD)-induced obesity models. In this study, we investigated the potential of dietary CAP to prevent HFD-induced MASLD. Methods: C57BL/6 mice were fed an HFD (60% kcal from fat) with or without 0.01% CAP supplementation for 26 weeks. We evaluated CAP’s effects on hepatic fat accumulation, inflammation, and mitochondrial function to determine its role in preventing MASLD. Results: CAP acts as a potent and selective agonist of the transient receptor potential vanilloid 1 (TRPV1) channel. We confirmed TRPV1 expression in the liver and demonstrated that CAP activates hepatic TRPV1, thereby preventing steatosis, improving insulin sensitivity, reducing inflammation, and enhancing fatty acid oxidation. These beneficial effects were observed in wild-type but not in TRPV1 knockout mice. Mechanistically, CAP-induced TRPV1 activation promotes calcium influx and activates AMPK, which leads to SIRT1-dependent upregulation of PPARα and PGC-1α, enhancing mitochondrial biogenesis and lipid metabolism. Conclusions: Our findings suggest that dietary CAP prevents MASLD through TRPV1 activation. TRPV1 signaling represents a promising therapeutic target for the prevention and management of MASLD in individuals with metabolic disorders. Full article

Obesity remains a major global health challenge with limited therapeutic options. Bromelain, a proteolytic enzyme complex derived from pineapple, has been recognized for its natural anti-inflammatory, anti-edematous, and appetite-suppressing properties. This study aimed to investigate the effects of bromelain on hypothalamic neuropeptides and metabolic markers in a high-fat diet (HFD)-induced obesity model in rats. Thirty-six male Wistar albino rats were randomly divided into four groups: standard diet (SD), standard diet with bromelain (SDBro), high-fat diet (HFD), and high-fat diet with bromelain (HFDBro). Obesity was induced by a 3-month HFD regimen, followed by bromelain supplementation (200 mg/kg/day, orally) for one month. Hypothalamic tissues were analyzed via ELISA for neuropeptide Y (NPY), pro-opiomelanocortin (POMC), glucose transporter 2 (GLUT2), fibroblast growth factor 2 (FGF2), and insulin-like growth factor 1 receptor (IGF1R). While NPY levels showed no significant changes, POMC increased in the HFD and was normalized with bromelain. GLUT2 was downregulated in the HFD and significantly restored by bromelain. FGF2 levels remained unchanged. IGF1R was upregulated in the HFD but reduced by bromelain, with an unexpected increase in SDBro. Overall, bromelain partially reversed HFD-induced disruptions in hypothalamic energy-regulating pathways, particularly affecting GLUT2 and POMC. These findings highlight bromelain’s potential role in central metabolic regulation under dietary stress. Full article

Resveratrol (RSV), a polyphenol found in a variety of berries and wines, is known for its anti-inflammatory, anticancer, and antioxidant properties. It has been suggested that RSV may play a role in the regulation of metabolic disorders, including diabetes and insulin resistance. However, in recent years, it has been reported to completely inhibit Akt kinase function in liver cells. Akt is a central protein involved in the metabolic function of insulin and is regulated by the phosphatidylinositol-3-kinase (PI3K) pathway. In this study, we examined the effect of RSV on insulin-induced insulin receptor (IR) phosphorylation and proteins involved in the PI3K/Akt pathway in a hepatic cell model, clone 9 (C9), and in hepatoma cells, Hepa 1-6 (H1-6). In both cell lines, RSV inhibited tyrosine phosphorylation of IR and insulin-induced activation of Akt. We also evaluated the effect of RSV on the activation of protein tyrosine phosphatase 1B (PTP1B), which is associated with IR dephosphorylation, and found that RSV increased PTP1B-Tyr¹⁵² phosphorylation in a time- and concentration-dependent manner. Furthermore, we found that the protein kinase C (PKC) inhibitors BIM and Gö6976 prevented the inhibition of Akt phosphorylation by RSV and increased the phosphorylation of Ser/Thr residues in IR, suggesting that PKC is involved in the inhibition of the insulin pathway by RSV. Thus, classical PKC isoforms impair the PI3K/Akt pathway at the IR and GSK3 and GS downstream levels; however, IRS-Tyr⁶³² phosphorylation remains unaffected. These results suggest that RSV can lead to insulin resistance by activating PTP1B and PKC, consequently affecting glucose homeostasis in hepatic cells. Full article

Background and Objectives: The management of type 2 diabetes (T2D) extends beyond glycemic control, requiring a more global strategy that includes optimization of body composition, even more so in the context of sarcopenia and visceral adiposity, as they contribute to poor outcomes. Past reviews have typically been focused on weight reduction or glycemic effectiveness, with limited inclusion of new therapies’ effects on muscle and fat distribution. In addition, the emergence of incretin-based therapies and dual agonists such as tirzepatide requires an updated synthesis of their impacts on body composition. This review attempts to bridge the gap by taking a systematic approach to how current blood-glucose lowering therapies affect lean body mass, fat mass, and the risk of sarcopenia in T2D patients. Materials and Methods: Between January 2015 and March 2025, we conducted a narrative review by searching the PubMed, Scopus, and Web of Science databases for English-language articles. The keywords were combinations of the following: “type 2 diabetes,” “lean body mass,” “fat mass,” “body composition,” “sarcopenia,” “GLP-1 receptor agonists,” “SGLT2 inhibitors,” “tirzepatide,” and “antidiabetic pharmacotherapy.” Reference lists were searched manually as well. The highest precedence was assigned to studies that aimed at adult type 2 diabetic subjects and reported body composition results. Inclusion criteria for studies were: (1) type 2 diabetic mellitus adult patients and (2) reporting measures of body composition (e.g., lean body mass, fat mass, or muscle function). We prioritized randomized controlled trials and large observational studies and excluded mixed diabetic populations, non-pharmacological interventions only, and poor reporting of body composition. Results: Metformin was widely found to be weight-neutral with minimal effects on muscle mass. Insulin therapy, being an anabolic hormone, often leads to fat mass accumulation and increases the risk of sarcopenic obesity. Incretin-based therapies induced substantial weight loss, mostly from fat mass. Notable results were observed in studies with tirzepatide, demonstrating superior reduction not only in fat mass, but also in visceral fat. Sodium-glucose cotransporter 2 inhibitors (SGLT2 inhibitors) promote fat loss but are associated with a small yet significant decrease in lean muscle mass. Conclusions: Blood-glucose lowering therapies demonstrated clinically relevant effects on body composition. Treatment should be personalized, balancing glycemic control, cardiovascular, and renal benefits, together with optimal impact on muscle mass along with glycemic, cardiovascular, and renal benefits. Full article

Lipopolysaccharide (LPS), the defining outer membrane component of Gram-negative bacteria, is a potent immunostimulant recognized by Toll-like receptor 4 (TLR4). While extensively studied for its roles in immune activation and barrier disruption, the potential function of LPS as a developmental cue remains largely unexplored. By leveraging Caenorhabditis elegans and its genetic and gnotobiotic advantages, we screened a panel of Escherichia coli LPS biosynthesis mutants. This screen revealed that the loss of outer core glycosylation in the ∆rfaG mutant causes significant developmental delay independent of bacterial metabolism. Animals exhibited developmental delay that was rescued by exogenous LPS or amino acid supplementation, implicating that LPS triggers nutrient-sensing signaling. Mechanistically, this developmental arrest was mediated by the host FOXO transcription factor DAF-16, which is the key effector of insulin/IGF-1 signaling (IIS). Our findings uncover an unprecedented role for microbial LPS as a critical regulator of host development, mediated through conserved host IIS pathways, fundamentally expanding our understanding of host–microbe crosstalk. Full article

Quercetin is a biologically active flavonoid compound that exerts numerous beneficial effects in humans and animals, including anti-diabetic activity. Its action has been explored in rodent models of type 1 and type 2 diabetes. It was revealed that quercetin mitigated diabetes-related hormonal and metabolic disorders and reduced oxidative and inflammatory stress. Its anti-diabetic effects were associated with advantageous changes in the relevant enzymes and signaling molecules. Quercetin positively affected, among others, superoxide dismutase, catalase, glutathione peroxidase, glucose transporter-2, glucokinase, glucose-6-phosphatase, glycogen phosphorylase, glycogen synthase, glycogen synthase kinase-3β, phosphoenolpyruvate carboxykinase, silent information regulator-1, sterol regulatory element-binding protein-1, insulin receptor substrate 1, phosphoinositide 3-kinase, and protein kinase B. The available data support the conclusion that the action of quercetin was pleiotropic since it alleviates a wide range of diabetes-related disorders. Moreover, no side effects were observed during treatment with quercetin in rodents. Given that human diabetes affects a large part of the population worldwide, the results of animal studies encourage clinical trials to evaluate the potential of quercetin as an adjunct to pharmacological therapies. Full article

Central nervous system (CNS) insulin signaling is involved in a broad array of cardiometabolic physiology, including glucose and lipid metabolism, feeding, energy expenditure, and blood pressure regulation. A key role for hypothalamic neuroendocrine and autonomic centers in regulating insulin-associated cardiovascular and metabolic physiology has been highlighted. However, it is still unclear which CNS site(s) initiate insulin-dependent neural cascades. While some investigations have suggested that circulating insulin can access hypothalamic regions by crossing the blood-brain barrier, other studies point to a necessity of other brain areas upstream of the hypothalamus to initiate central insulin actions. In this context, accumulating evidence points to a possible involvement of the sensory circumventricular organs (CVOs), unique areas located outside of the blood-brain barrier, in insulin-dependent cardiometabolic homeostasis. Here, the multifaceted roles for the sensory CVOs in cardiovascular and metabolic regulation, with a special emphasis on insulin receptor pathways, are discussed. Full article

Hyperinsulinemia refers to an elevated level of circulating insulin (80 and 100 µU/mL), often leading to metabolic disorders such as obesity, insulin resistance, and type 2 diabetes (T2D). There is no precise and universally accepted definition of hyperinsulinemia and insulin resistance. The literature in the field remains unclear regarding whether insulin resistance precedes the development of hyperinsulinemia. Recently, a new hypothesis has been proposed suggesting that chronic hyperinsulinemia precedes and causes insulin resistance. The causes of the initiation of hyperinsulinemia, insulin resistance, and type 2 diabetes are multifactorial. Thus, it is not easy to define in general. Recent work demonstrates that the main prediabetic factor leading to insulin resistance is chronic hyperinsulinemia. However, recent work in the literature proposes that relatively long-term hyperinsulinemia does precede insulin resistance and already promotes cardiovascular remodeling. This later may lead to the development of vascular diseases such as hypertension. Thus, defining hyperinsulinemia and insulin resistance, as well as their signaling pathways implicated in the development of type 2 diabetes (T2D), needs to be clarified. Full article

Endometriosis is a disorder characterized by the presence of endometrial tissue outside the uterus, leading to dyspareunia, chronic pelvic pain, dysuria, and infertility. The latter has been related to implantation failure associated with alterations in decidualization, a process regulated by sex hormones such as progesterone. Membrane progesterone receptor β (mPRβ) exhibits a lower expression in endometriotic tissues than in normal endometrial ones. However, the role of mPRβ in decidualization is unknown. This work aimed to investigate whether mPRβ plays a role in the decidualization of endometrial stromal cells (ESCs) derived from women with and without endometriosis. The mPR agonist OrgOD-2 induced the gene expression of key decidualization markers (insulin-like growth factor binding protein 1, prolactin, transcription factor heart and neural crest derivatives-expressed transcript 2, and fork-head transcription factor) in healthy ESCs, eutopic (uterine cavity), and ectopic (outside of the uterine cavity) ESCs from women with endometriosis. Notably, the expression of the decidualization markers was lower in endometriotic cells than in healthy endometrial ones. An siRNA mediated knockdown of mPRβ reduced the expression of decidualization-associated genes in ESCs treated with a decidualization stimuli, regardless of whether cells were derived from healthy women or those with endometriosis. Our data suggest that progesterone, through mPRβ activation, regulates the decidualization process in endometrial stromal cells from women with and without endometriosis. Full article

Objective: This study aimed to identify plasma exosomal microRNAs (miRNAs) associated with weight loss and type 2 diabetes (T2D) remission following low-calorie diet (LCD) intervention. Methods: A 6-month dietary intervention targeting T2D remission was conducted among individuals with T2D. Participants underwent a 3-month intensive weight loss phase consuming LCD (815–835 kcal/day) and a 3-month weight maintenance phase (N = 32). Sixteen participants were randomly selected for characterization of plasma-derived exosomal miRNA profiles at baseline, 3 months, and 6 months using small RNA sequencing. Linear mixed-effects models were used to identify differentially expressed exosomal miRNAs between responders and non-responders. Pathway enrichment analyses were conducted using target mRNAs of differentially expressed miRNAs. Logistic regression models assessed the predictive value of differentially expressed miRNAs for T2D remission. Results: Among the 16 participants, 6 achieved weight loss ≥10% and 12 achieved T2D remission. Eighteen exosomal miRNAs, including miR-92b-3p, miR-495-3p, and miR-452b-5p, were significantly associated with T2D remission and weight loss. Pathway analyses revealed enrichment in PI3K-Akt pathway, FoxO signaling pathway, and insulin receptor binding. The addition of individual miRNAs including miR-15b-3p, miR-26a-5p, and miR-3913-5p to base model improved the area under the curve values by 0.02–0.08 at 3 months and by 0.02–0.06 at 6 months for T2D remission. Conclusions: This study identified exosomal miRNAs associated with T2D remission and weight loss following LCD intervention. Several exosomal miRNAs might serve as valuable predictors of T2D remission in response to LCD intervention. Full article

Spurred by the enormous therapeutic success of glucagon-like peptide-1 receptor (GLP-1R) agonists (GLP1-RAs) against diabetes and obesity, glucagon family receptor pharmacology has garnered a tremendous amount of interest. Glucagon family receptors, e.g., the glucagon receptor itself (GCGR), the GLP-1R, and the glucose-dependent insulinotropic peptide receptor (GIPR), belong to the incretin receptor superfamily, i.e., receptors that increase blood glucose-dependent insulin secretion. All incretin receptors are class B1 G protein-coupled receptors (GPCRs), coupling to the G_s type of heterotrimeric G proteins which activates adenylyl cyclase (AC) to produce cyclic adenosine monophosphate (cAMP). Most GPCRs undergo desensitization, i.e., uncouple from G proteins and internalize, thanks to interactions with the βarrestins (arrestin-2 and -3). Since the βarrestins can also mediate their own G protein-independent signaling, any given GPCR can theoretically signal (predominantly) either via G proteins or βarrestins, i.e., be a G protein- or βarrestin-“biased” receptor, depending on the bound ligand. A plethora of experimental evidence suggests that the GLP-1R does not undergo desensitization in physiologically relevant tissues in vivo, but rather, it produces robust and prolonged cAMP signals. A particular property of constant cycling between the cell membrane and caveolae/lipid rafts of the GLP-1R may underlie its lack of desensitization. In contrast, GIPR signaling is extensively mediated by βarrestins and the GIPR undergoes significant desensitization, internalization, and downregulation, which may explain why both agonists and antagonists of the GIPR exert the same physiological effects. Here, we discuss this evidence and make a case for the GLP-1R being a phenotypically or functionally G_s-selective receptor. We also discuss the implications of this for the development of GLP-1R poly-ligands, which are increasingly pursued for the treatment of obesity and other diseases. Full article

Background: Sodium–glucose cotransporter 2 (SGLT2) inhibitors have transformed type 2 diabetes mellitus (T2DM) management by promoting glucosuria, lowering glycated hemoglobin (HbA1c), blood pressure, and weight; however, their use is limited by genitourinary infections and ketoacidosis. Phytocannabinoids—bioactive compounds from Cannabis sativa—exhibit multi-target pharmacology, including interactions with cannabinoid receptors, Peroxisome Proliferator-Activated Receptors (PPARs), Transient Receptor Potential (TRP) channels, and potentially SGLT2. Objective: To evaluate the potential of phytocannabinoids as novel modulators of renal glucose reabsorption via SGLT2 and to compare their efficacy, safety, and pharmacological profiles with synthetic SGLT2 inhibitors. Methods: We performed a narrative review encompassing the following: (1) the molecular and physiological roles of SGLT2; (2) chemical classification, natural sources, and pharmacokinetics/pharmacodynamics of major phytocannabinoids (Δ⁹-Tetrahydrocannabinol or Δ⁹-THC, Cannabidiol or CBD, Cannabigerol or CBG, Cannabichromene or CBC, Tetrahydrocannabivarin or THCV, and β-caryophyllene); (3) in silico docking and drug-likeness assessments; (4) in vitro assays of receptor binding, TRP channel modulation, and glucose transport; (5) in vivo rodent models evaluating glycemic control, weight change, and organ protection; (6) pilot clinical studies of THCV and case reports of CBD/BCP; (7) comparative analysis with established synthetic inhibitors. Results: In silico studies identify high-affinity binding of several phytocannabinoids within the SGLT2 substrate pocket. In vitro, CBG and THCV modulate SGLT2-related pathways indirectly via TRP channels and CB receptors; direct IC₅₀ values for SGLT2 remain to be determined. In vivo, THCV and CBD demonstrate glucose-lowering, insulin-sensitizing, weight-reducing, anti-inflammatory, and organ-protective effects. Pilot clinical data (n = 62) show that THCV decreases fasting glucose, enhances β-cell function, and lacks psychoactive side effects. Compared to synthetic inhibitors, phytocannabinoids offer pleiotropic benefits but face challenges of low oral bioavailability, polypharmacology, inter-individual variability, and limited large-scale trials. Discussion: While preclinical and early clinical data highlight phytocannabinoids’ potential in SGLT2 modulation and broader metabolic improvement, their translation is impeded by significant challenges. These include low oral bioavailability, inconsistent pharmacokinetic profiles, and the absence of standardized formulations, necessitating advanced delivery system development. Furthermore, the inherent polypharmacology of these compounds, while beneficial, demands comprehensive safety assessments for potential off-target effects and drug interactions. The scarcity of large-scale, well-controlled clinical trials and the need for clear regulatory frameworks remain critical hurdles. Addressing these aspects is paramount to fully realize the therapeutic utility of phytocannabinoids as a comprehensive approach to T2DM management. Conclusion: Phytocannabinoids represent promising multi-target agents for T2DM through potential SGLT2 modulation and complementary metabolic effects. Future work should focus on pharmacokinetic optimization, precise quantification of SGLT2 inhibition, and robust clinical trials to establish efficacy and safety profiles relative to synthetic inhibitors. Full article