Dysfunctions, molecular mechanisms, and therapeutic strategies of pancreatic β-cells in diabetes

Life-threatening risk factors contribute to the development of diseases with the highest mortality through the induction of regulated necrotic cell death

Chronic diseases affecting the cardiovascular system, diabetes mellitus, neurodegenerative diseases, and various other organ-specific conditions, involve different underlying pathological processes. However, they share common risk factors that contribute to the development and progression of these diseases, including air pollution, hypertension, obesity, high cholesterol levels, smoking and alcoholism. In this review, we aim to explore the connection between four types of diseases with different etiologies and various risk factors. We highlight that the presence of risk factors induces regulated necrotic cell death, leading to the release of damage-associated molecular patterns (DAMPs), ultimately resulting in sterile inflammation. Therefore, DAMP-mediated inflammation may be the link explaining how risk factors can lead to the development and maintenance of chronic diseases. To explore these processes, we summarize the main cell death pathways activated by the most common life-threatening risk factors, the types of released DAMPs and how these events are associated with the pathophysiology of diseases with the highest mortality. Various risk factors, such as smoking, air pollution, alcoholism, hypertension, obesity, and high cholesterol levels induce regulated necrosis. Subsequently, the release of DAMPs leads to chronic inflammation, which increases the risk of many diseases, including those with the highest mortality rates.

Oxidative stress and inflammation mediate the adverse effects of cadmium exposure on all-cause and cause-specific mortality in patients with diabetes and prediabetes

BACKGROUND

The effect of cadmium exposure on mortality risk among individuals with diabetes and prediabetes remains unclear, particularly regarding potential mediation by oxidative stress and inflammation. This study aimed to investigate the associations of blood cadmium levels with all-cause, cardiovascular disease (CVD), and cancer mortality and the mediating effects of oxidative stress and inflammation biomarkers in patients with diabetes and prediabetes.

METHODS

In this prospective cohort study, we analyzed 17,687 adults with diabetes and prediabetes from the National Health and Nutrition Examination Survey (NHANES, 1999-2018). Nine biomarkers related to oxidative stress (gamma-glutamyl transferase [GGT], uric acid [UA], high-density lipoprotein [HDL], UA to HDL ratio [UHR]) and inflammation (neutrophil-lymphocyte ratio [NLR], monocyte-lymphocyte ratio [MLR], neutrophil-monocyte-lymphocyte ratio [NMLR], systemic inflammation response index [SIRI], systemic immune-inflammation index [SII]) were systematically assessed. Kaplan-Meier survival analysis, Cox proportional hazards models, and restricted cubic splines (RCS) were applied to evaluate the association of cadmium with mortality risk. Generalized linear models were used to assess the association of cadmium with oxidative stress and inflammation biomarkers, while Cox regression and RCS evaluated their effects on mortality. Causal mediation analysis identified biological pathways mediated by oxidative stress and inflammation. Stratified and sensitivity analyses were further employed to confirm the robustness of the results.

RESULTS

During 161,047.75 person-years of follow-up, 3562 deaths occurred, including 1214 from CVD and 680 from cancer. Higher blood cadmium levels were associated with increased risks of all-cause mortality (fully adjusted hazard ratio [HR]: 2.17; 95% confidence interval [CI] 1.69-2.79, comparing highest vs. lowest quartile), CVD mortality (HR 2.06; 95% CI 1.41-3.02), and cancer mortality (HR 2.38; 95% CI 1.47-3.85), without evidence of nonlinear relationship. Mediation analyses indicated that UA, NLR, MLR, NMLR, and SIRI partially mediated the associations of cadmium with all-cause and CVD mortality, although the mediated proportions were relatively modest (ranging from 1.4 to 4.8%). Additionally, GGT mediated a small fraction of the associations with all-cause and cancer mortality.

CONCLUSION

Cadmium exposure increases the risk of all-cause, CVD, and cancer mortality in patients with diabetes and prediabetes. Oxidative stress and inflammation appear to partially mediate this adverse effect. These findings emphasize the urgent need for targeted interventions to reduce cadmium-related mortality risks.

RESEARCH INSIGHTS

What is currently known about this topic? Cadmium exposure is linked to increased mortality. Oxidative stress and inflammation are critical in diabetes development and complications. What is the key research question? Does cadmium exposure increase mortality risk in patients with diabetes and prediabetes? Are oxidative stress and inflammation involved in mediating these effects? What is new? Cadmium exposure increases all-cause and cause-specific mortality in diabetes and prediabetes. Oxidative stress and inflammation mediate these associations. How might this study influence clinical practice? Monitor cadmium, oxidative stress, and inflammation to reduce mortality in diabetes and prediabetes.

Mechanism and therapeutic potential of hippo signaling pathway in type 2 diabetes and its complications

Loss of pancreatic islet cell mass and function is one of the most important factors in the development of type 2 diabetes mellitus, and hyperglycemia-induced lesions in other organs are also associated with apoptosis or hyperproliferation of the corresponding tissue cells. The Hippo signaling pathway is a key signal in the regulation of cell growth, proliferation and apoptosis, which has been shown to play an important role in the regulation of diabetes mellitus and its complications. Excessive activation of the Hippo signaling pathway under high glucose conditions triggered apoptosis and decreased insulin secretion in pancreatic islet cells, while dysregulation of the Hippo signaling pathway in the cells of other organ tissues led to proliferation or apoptosis and promoted tissue fibrosis, which aggravated the progression of diabetes mellitus and its complications. This article reviews the mechanisms of Hippo signaling, its individual and reciprocal regulation in diabetic pancreatic pathology, and its emerging role in the pathophysiology of diabetic complications. Potential therapeutics for diabetes mellitus that have been shown to target the Hippo signaling pathway are also summarized to provide information for the clinical management of type 2 diabetes mellitus.

NFAT5 exacerbates β-cell ferroptosis by suppressing the transcription of PRDX2 in obese type 2 diabetes mellitus

Pancreatic β-cell damage is a critical pathological mechanism in the progression of obese type 2 diabetes mellitus (T2DM). However, the exact underlying mechanism remains unclear. We established an obese T2DM mouse model via high-fat diet feeding. The protein expression profiles of pancreatic tissues from normal and obese T2DM mice were analyzed, revealing that nuclear factor of activated T cells 5 (NFAT5) and ferroptosis are potential mediators and mechanisms of β-cell damage in obese T2DM mice. In vitro, high glucose and palmitate treatment resulted in increased NFAT5 expression and nuclear translocation in MIN6 cells. Inhibition of NFAT5 expression by shRNA significantly reduced ferroptosis and improved the reduction in insulin secretion in palmitic acid and high glucose (PG)-treated MIN6 cells. Luciferase reporter and chromatin immunoprecipitation (ChIP) assays confirmed the ability of NFAT5 to bind to the peroxiredoxin 2 (PRDX2) promoter, leading to the downregulation of PRDX2 transcription. Subsequent rescue experiments confirmed that NFAT5 is involved in PG-induced ferroptosis in MIN6 cells by inhibiting the expression of PRDX2. Finally, we demonstrated that the use of the AAV8-RIP2-miR30-shNFAT5 vector to specifically inhibit the expression of NFAT5 in β-cells significantly diminishes ferroptosis in obese T2DM mice, thereby increasing insulin secretion and improving abnormal glucose tolerance. These findings collectively highlight the therapeutic potential of targeting NFAT5 in β cells to counteract obesity-induced T2DM.

Gallic acid: a dietary metabolite's therapeutic potential in the management of atherosclerotic cardiovascular disease

Atherosclerotic cardiovascular disease (ASCVD) causes significant morbidity and mortality globally. Most of the chemicals specifically target certain pathways and minimally impact other diseases associated with ASCVD. Moreover, interactions of these drugs can cause toxic reactions. Consequently, the exploration of multi-targeted and safe medications for treating and preventing ASCVD has become an increasingly popular trend. Gallic acid (GA), a natural secondary metabolite found in various fruits, plants, and nuts, has demonstrated potentials in preventing and treating ASCVD, in addition to its known antioxidant and anti-inflammatory effects. It alleviates the entire process of atherosclerosis (AS) by reducing oxidative stress, improving endothelial dysfunction, and inhibiting platelet activation and aggregation. Additionally, GA can treat ASCVD-related diseases, such as coronary heart disease (CHD) and cerebral ischemia. However, the pharmacological actions of GA in the prevention and treatment of ASCVD have not been comprehensively reviewed, which limits its clinical development. This review primarily summarizes the in vitro and in vivo pharmacological actions of GA on the related risk factors of ASCVD, AS, and ASCVD. Additionally, it provides a comprehensive overview of the toxicity, extraction, synthesis, pharmacokinetics, and pharmaceutics of GA,aimed to enhance understanding of its clinical applications and further research and development.

The Emerging Scenario of Ferroptosis in Pancreatic Cancer Tumorigenesis and Treatment

Pancreatic cancer remains one of the most lethal forms of cancer. Currently, there is a lack of effective drug treatments for pancreatic cancer. However, as a newly discovered form of non-apoptotic cell death, ferroptosis has garnered increasing attention in relation to pancreatic cancer. Understanding the role of ferroptosis in the tumorigenesis and treatment of pancreatic cancer may enable more effective clinical trials and treatments for pancreatic cancer and may minimize side effects or restrict the emergence of drug resistance. In this review, we summarize the current knowledge regarding the process and underlying mechanisms of ferroptosis, as well as its dual role in both promoting tumorigenesis and facilitating treatment strategies for pancreatic cancer. Additionally, how ferroptosis is implicated in the development of pancreatitis and insulin resistance, indicating that ferroptosis may play an important role in the risk of pancreatitis- and insulin-resistance-related pancreatic cancers, is also addressed.

Tangningtongluo Tablet ameliorates pancreatic damage in diabetic mice by inducing autophagy and inhibiting the PI3K/Akt/mTOR signaling pathway

BACKGROUND

Diabetes is a metabolic disease characterized by hyperglycaemia. Tangningtongluo Tablet (TNTL) is an inpatient formula extensively utilized to treat diabetes mellitus (DM), but the protective mechanism is not clear. This study aimed to investigate the relevant mechanisms by which TNTL affects pancreatic damage in diabetic mice and autophagy.

METHODS

The impact of TNTL on pancreatic damage in diabetic mice in vitro and in vivo was investigated via glucose and lipid metabolism analyses, HE staining, CCK-8, TUNEL staining, Annexin V/PI, and Western blotting. Molecular docking and Western blotting were used to verify the results of network pharmacological analysis, which was carried out to explore the mechanism by which TNTL affects DM. The autophagosome levels were visualized via RFP-GFP-LC3 and transmission electron microscopy, and lysosomal function was evaluated via Lysotracker red staining. Western blot, immunohistochemistry and immunofluorescence staining were used to detect the expression of the autophagy proteins LC3, p62 and LAMP2.

RESULTS

Compared with the model group, TNTL protected pancreas from oxidative stress, decreased the level of MDA, increased the levels of SOD and GSH-px, induced the occurrence of autophagy and decreased the levels of apoptotic factors. Moreover, TNTL inhibited the protein expression of p-PI3K, p-Akt and p-mTOR, increased the levels of LC3 and LAMP2 and decreased the level of p62, and the autophagy inhibitor CQ blocked the protective effect of TNTL on pancreatic damage in diabetic mice.

CONCLUSION

These results demonstrated that TNTL ameliorated pancreatic damage in diabetic mice by inhibiting the PI3K/Akt/mTOR signaling and regulating autophagy.

Neural Precursor Cell-Expressed Developmentally Downregulated Protein 4 (NEDD4)-Mediated Ubiquitination of Glutathione Peroxidase 4 (GPX4): A Key Pathway in High-Glucose-Induced Ferroptosis in Corpus Cavernosum Smooth Muscle Cells

Pharmacological treatment of diabetes mellitus-induced erectile dysfunction (DMED) has become increasingly challenging due to the limited efficacy of phosphodiesterase type 5 inhibitors (PDE5i). As the global prevalence of DM continues, there is a critical need for novel therapeutic strategies to address DMED. In our previous studies, we found that Glutathione peroxidase 4 (GPX4), a ferroptosis inhibitor, can ameliorate DMED in diabetic rats. However, the specific role of GPX4 in corpus cavernosum smooth muscle cells (CCSMCs) and its regulatory mechanisms remain unclear. In this study, we established primary cultures of CCSMCs and systematically analyzed the role of GPX4 under high-glucose conditions. To further elucidate the upstream regulatory pathways of GPX4, we employed immunoprecipitation coupled with mass spectrometry (IP-MS) to identify potential interacting proteins. Additionally, co-immunoprecipitation (Co-IP) and cycloheximide (CHX) chase assays were conducted to explore the regulatory dynamics and post-translational stability of GPX4. Under high-glucose conditions, the expression of GPX4 in CCSMCs is significantly downregulated, leading to an increase in intracellular oxidative stress and heightened levels of ferroptosis, accompanied by dysfunction in smooth muscle cell relaxation. Furthermore, the CHX chase assay revealed that high glucose accelerates GPX4 protein degradation via the ubiquitin-proteasome pathway. Subsequent IP-MS identified NEDD4, an E3 ubiquitin ligase, as a potential interacting partner of GPX4. Further validation demonstrated that NEDD4 modulates the ubiquitination process of GPX4, thereby influencing its stability and expression. In conclusion, we identified NEDD4 as a key regulator of GPX4 stability through ubiquitin-mediated proteasomal degradation. These findings suggest potential therapeutic strategies targeting the NEDD4-GPX4 axis to alleviate DMED pathology.

Exocrine pancreatic inflammation in canine diabetes mellitus - An active offender?

The purpose of this review is to examine the current scientific literature regarding the interplay between the exocrine and endocrine pancreas, specifically the role of the exocrine pancreas in the pathogenesis of canine diabetes mellitus. β-cell death caused by exocrine pancreatic inflammation is thought to be an under-recognised contributor to diabetes mellitus in dogs, with up to 30 % of canine diabetic patients with concurrent evidence of pancreatitis at post-mortem examination. Current diagnostics for pancreatitis are imprecise, and treatments for both diseases individually have their own limitations: diabetes through daily insulin injections, which has both welfare and financial implications for the stakeholders, and pancreatitis through treatment of clinical signs, such as analgesia and anti-emetics, rather than targeted treatment of the underlying cause. This review will consider the evidence for exocrine pancreatic inflammation making an active contribution to pancreatic β-cell loss and insulin-deficiency diabetes in the dog and explore current and potential future diagnostic and treatment avenues to improve outcomes for these patients.

Protective Effects of Food-Derived Kaempferol on Pancreatic β-Cells in Type 1 Diabetes Mellitus

BACKGROUND

Kaempferol (KPF), a flavonoid abundant in edible plants, possesses potent anti-inflammatory and antioxidant properties beneficial with notable health benefits.

OBJECTIVE

To evaluate the protective effects of KPF on metabolic disturbances and pancreatic damage in a Type 1 diabetes mellitus (T1DM) mouse model.

METHODS

Male C57BL/6 mice were divided into normal, T1DM, T1DM + KPF 25 mg/kg, and T1DM + KPF 50 mg/kg groups. T1DM was induced by streptozotocin (STZ). KPF was administered via intraperitoneal injection for 2 weeks. After 4 weeks from the start, metabolic parameters, pancreatic histology, and plasma metabolites were analyzed. Network pharmacology and molecular docking identified key targets and pathways. In vitro, INS-1 cells were used to assess reactive oxygen species (ROS) production and apoptosis.

RESULTS

KPF significantly reduced blood glucose (GLU) and triglyceride (TG) levels, increased high-density lipoprotein (HDL) levels, and preserved pancreatic β-cell structure. Metabolomics revealed changes in energy metabolism and oxidative stress-related metabolites. Network analysis highlighted the PI3K/AKT/mTOR pathway, with strong binding affinities to targets such as AKT1. In vitro, KPF decreased ROS production in INS-1 cells; this effect was reversed by a PI3K/AKT inhibitor. KPF also reduced apoptosis in INS-1 cells.

CONCLUSIONS

KPF ameliorates metabolic disturbances and pancreatic damage in T1DM mice, suggesting potential as a functional food ingredient for diabetes management.

Type 2 diabetes mellitus in adults: pathogenesis, prevention and therapy

Type 2 diabetes (T2D) is a disease characterized by heterogeneously progressive loss of islet β cell insulin secretion usually occurring after the presence of insulin resistance (IR) and it is one component of metabolic syndrome (MS), and we named it metabolic dysfunction syndrome (MDS). The pathogenesis of T2D is not fully understood, with IR and β cell dysfunction playing central roles in its pathophysiology. Dyslipidemia, hyperglycemia, along with other metabolic disorders, results in IR and/or islet β cell dysfunction via some shared pathways, such as inflammation, endoplasmic reticulum stress (ERS), oxidative stress, and ectopic lipid deposition. There is currently no cure for T2D, but it can be prevented or in remission by lifestyle intervention and/or some medication. If prevention fails, holistic and personalized management should be taken as soon as possible through timely detection and diagnosis, considering target organ protection, comorbidities, treatment goals, and other factors in reality. T2D is often accompanied by other components of MDS, such as preobesity/obesity, metabolic dysfunction associated steatotic liver disease, dyslipidemia, which usually occurs before it, and they are considered as the upstream diseases of T2D. It is more appropriate to call "diabetic complications" as "MDS-related target organ damage (TOD)", since their development involves not only hyperglycemia but also other metabolic disorders of MDS, promoting an up-to-date management philosophy. In this review, we aim to summarize the underlying mechanism, screening, diagnosis, prevention, and treatment of T2D, especially regarding the personalized selection of hypoglycemic agents and holistic management based on the concept of "MDS-related TOD".

PEGylated β-Cell-Targeting Exosomes from Mesenchymal Stem Cells Improve β Cell Function and Quantity by Suppressing NRF2-Mediated Ferroptosis

Background

The depletion of β cell mass is widely recognized as a significant contributor to the progression of type 2 diabetes mellitus (T2DM). Exosomes derived from mesenchymal stem cells (MSC-EXOs) hold promise as cell-free therapies for treating T2DM. However, the precise effects and mechanisms through which MSC-EXO affects β cell function remain incompletely understood, and the limited ability of MSC-EXO to target β cells and the short blood circulation time hampers its therapeutic effectiveness.

Methods

The effects of MSC-EXO were investigated in T2DM mice induced by a high-fat diet combined with STZ. Additionally, the high glucose-stimulated INS-1 cell line was used to investigate the potential mechanism of MSC-EXO. Michael addition reaction-mediated chemical coupling was used to modify the surface of the exosome membrane with a β-cell-targeting aptamer and polyethylene glycol (PEG). The β-cell targeting and blood circulation time were evaluated, and whether this modification enhanced the islet-protective effect of MSC-EXO was further analyzed.

Results

We observed that the therapeutic effects of MSC-EXO on T2DM manifested through the reduction of random blood glucose levels, enhancement of glucose and insulin tolerance, and increased insulin secretion. These effects were achieved by augmenting β cell mass via inhibiting nuclear factor erythroid 2-related factor 2 (NRF2)-mediated ferroptosis. Mechanistically, MSC-EXOs play a role in the NRF2-mediated anti-ferroptosis mechanism by transporting active proteins that are abundant in the AKT and ERK pathways. Moreover, compared to MSC-EXOs, aptamer- and PEG-modified exosomes (Apt-EXOs) were more effective in islet protection through PEG-mediated cycle prolongation and aptamer-mediated β-cell targeting.

Conclusion

MSC-EXO suppresses NRF2-mediated ferroptosis by delivering bioactive proteins to regulate the AKT/ERK signaling pathway, thereby improving the function and quantity of β cells. Additionally, Apt-EXO may serve as a novel drug carrier for islet-targeted therapy.

Ferroptosis and iron metabolism in diabetes: Pathogenesis, associated complications, and therapeutic implications

Diabetes mellitus is a complex chronic disease, considered as one of the most common metabolic disorders worldwide, posing a major threat to global public health. Ferroptosis emerges as a novel mechanism of programmed cell death, distinct from apoptosis, necrosis, and autophagy, driven by iron-dependent lipid peroxidation accumulation and GPx4 downregulation. A mounting body of evidence highlights the interconnection between iron metabolism, ferroptosis, and diabetes pathogenesis, encompassing complications like diabetic nephropathy, cardiomyopathy, and neuropathy. Moreover, ferroptosis inhibitors hold promise as potential pharmacological targets for mitigating diabetes-related complications. A better understanding of the role of ferroptosis in diabetes may lead to an improvement in global diabetes management. In this review, we delve into the intricate relationship between ferroptosis and diabetes development, exploring associated complications and current pharmacological treatments.

Anti-Inflammatory Role of the Klotho Protein and Relevance to Aging

The α-Klotho protein (hereafter Klotho) is an obligate coreceptor for fibroblast growth factor 23 (FGF23). It is produced in the kidneys, brain and other sites. Klotho insufficiency causes hyperphosphatemia and other anomalies. Importantly, it is associated with chronic pathologies (often age-related) that have an inflammatory component. This includes atherosclerosis, diabetes and Alzheimer's disease. Its mode of action in these diseases is not well understood, but it inhibits or regulates multiple major pathways. Klotho has a membrane form and a soluble form (s-Klotho). Cytosolic Klotho is postulated but not well characterized. s-Klotho has endocrine properties that are incompletely elucidated. It binds to the FGF receptor 1c (FGFR1c) that is widely expressed (including endothelial cells). It also attaches to soluble FGF23, and FGF23/Klotho binds to FGFRs. Thus, s-Klotho might be a roaming FGF23 coreceptor, but it has other functions. Notably, Klotho (cell-bound or soluble) counteracts inflammation and appears to mitigate related aging (inflammaging). It inhibits NF-κB and the NLRP3 inflammasome. This inflammasome requires priming by NF-κB and produces active IL-1β, membrane pores and cell death (pyroptosis). In accord, Klotho countered inflammation and cell injury induced by toxins, damage-associated molecular patterns (DAMPs), cytokines, and reactive oxygen species (ROS). s-Klotho also blocks the TGF-β receptor and Wnt ligands, which lessens fibrotic disease. Low Klotho is associated with loss of muscle mass (sarcopenia), as occurs in aging and chronic diseases. s-Klotho counters the inhibitory effects of myostatin and TGF-β on muscle, reduces inflammation, and improves muscle repair following injury. The inhibition of TGF-β and other factors may also be protective in diabetic retinopathy and age-related macular degeneration (AMD). This review examines Klotho functions especially as related to inflammation and potential applications.

Therapeutic effect of oral insulin-chitosan nanobeads pectin-dextrin shell on streptozotocin-diabetic male albino rats

The current study inspects the therapeutic effects of orally ingested insulin-loaded chitosan nanobeads (INS-CsNBs) with a pectin-dextrin (PD) coating on streptozotocin (STZ)-induced diabetes in Wistar rats. The study also assessed antioxidant effects in pancreatic tissue homogenate, insulin, C-peptide, and inflammatory markers interleukin-1 beta and interleukin-6 (IL-1β and IL-6) in serum. Additionally, histopathological and immunohistochemical examination of insulin granules, oxidative stress, nuclear factor kappa B (NF-κB P65), and sirtuin-1 (SIRT-1) protein detection, as well as gene expression of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), B-cell lymphoma 2 (Bcl2), and Bcl-2-associated X protein (Bax) in pancreatic tissue were investigated. After induction of diabetes with STZ, rats were allocated into 6 groups: the normal control (C), the diabetic control (D), and the diabetic groups treated with INS-CsNBs coated with PD shell (50 IU/kg) (NF), free oral insulin (10 IU/kg) (FO), CsNBs-PD shell (50 IU/kg) (NB), and subcutaneous insulin (10 IU/kg) (Sc). The rats were treated daily for four weeks. Treatment of diabetic rats with INS-CsNBs coated with PD shell resulted in a significant improvement in blood glucose levels, elevated antioxidant activities, decreased NF-κB P65, IL-1β, and IL-6 levels, upregulated Nrf-2 and HO-1, in addition to a marked improvement in the histological architecture and integrity compared to the diabetic group. The effects of oral INS-CsNBs administration were comparable to those of subcutaneous insulin. In conclusion, oral administration of INS-loaded Cs-NBs with a pectin-dextrin shell demonstrated an ameliorative effect on STZ-induced diabetes, avoiding the drawbacks of subcutaneous insulin.

TXNIP-NLRP3-GSDMD axis-mediated inflammation and pyroptosis of islet β-cells is involved in cigarette smoke-induced hyperglycemia, which is alleviated by andrographolide

Epidemiologic surveys have indicated that cigarette smoking is an important risk factor for diabetes, but its mechanisms remain unclear. Andrographolide, an herb traditionally utilized in medicine, provides anti-inflammatory benefits for various diseases. In the present work, 265 patients with Type 2 diabetes (T2D) were investigated, and male C57BL/6 mice were exposed to cigareete smoke (CS) and/or to intraperitoneally injected andrographolide for 3 months. To elucidate the mechanism of CS-induced hyperglycemia and the protective mechanism of andrographolide, MIN6 cells were exposed to cigarette smoke extract (CSE) and/or to andrographolide. Our data from 265 patients with T2D showed that urinary creatinine and serum inflammatory cytokines (interleukin 6 (IL-6), IL-8, IL-1β, and tumor necrosis factor α (TNF-α)) increased with smoking pack-years. In a mouse model, CS induced hyperglycemia, decreased insulin secretion, and elevated inflammation and pyroptosis in β-cells of mice. Treatment of mice with andrographolide preserved pancreatic function by reducing the expression of inflammatory cytokines; the expression of TXNIP, NLRP3, cleaved caspase 1, IL-1β; and the N-terminal of gasdermin D (GSDMD) protein. For MIN6 cells, CSE caused increasing secretion of the inflammatory cytokines IL-6 and IL-1β, and the expression of TXNIP and pyroptosis-related proteins; however, andrographolide alleviated these changes. Furthermore, silencing of TXNIP showed that the blocking effect of andrographolide may be mediated by TXNIP. In sum, our results indicate that CS induces hyperglycemia through TXNIP-NLRP3-GSDMD axis-mediated inflammation and pyroptosis of islet β-cells and that andrographolide is a potential therapeutic agent for CS-induced hyperglycemia.

Synergistic Effect of a Flavonoid-Rich Cocoa-Carob Blend and Metformin in Preserving Pancreatic Beta Cells in Zucker Diabetic Fatty Rats

The loss of functional beta-cell mass in diabetes is directly linked to the development of diabetic complications. Although dietary flavonoids have demonstrated antidiabetic properties, their potential effects on pancreatic beta-cell preservation and their synergistic benefits with antidiabetic drugs remain underexplored. We have developed a potential functional food enriched in flavonoids by combining cocoa powder and carob flour (CCB), which has shown antidiabetic effects. Here, we investigated the ability of the CCB, alone or in combination with metformin, to preserve pancreatic beta cells in an established diabetic context and their potential synergistic effect. Zucker diabetic fatty rats (ZDF) were fed a CCB-rich diet or a control diet, with or without metformin, for 12 weeks. Markers of pancreatic oxidative stress and inflammation, as well as relative beta-cell mass and beta-cell apoptosis, were analyzed. Results demonstrated that CCB feeding counteracted pancreatic oxidative stress by enhancing the antioxidant defense and reducing reactive oxygen species. Moreover, the CCB suppressed islet inflammation by preventing macrophage infiltration into islets and overproduction of pro-inflammatory cytokines, along with the inactivation of nuclear factor kappa B (NFκB). As a result, the CCB supplementation prevented beta-cell apoptosis and the loss of beta cells in ZDF diabetic animals. The observed additive effect when combining the CCB with metformin underscores its potential as an adjuvant therapy to delay the progression of type 2 diabetes.

Dioscin: Therapeutic potential for diabetes and complications

Diabetes mellitus is a widespread metabolic disorder with increasing incidence worldwide, posing a considerable threat to human health because of its complications. Therefore, cost-effective antidiabetic drugs with minimal side effects are urgently needed. Dioscin, a naturally occurring compound, helps to reduce the complications of diabetes mellitus by regulating glucose and lipid metabolism, protecting islet β cells, improving insulin resistance, and inhibiting oxidative stress and inflammatory response. Plant-derived dioscin reduces the risk of toxicity and side effects associated with chemically synthesized drugs. It is a promising option for treating diabetes mellitus because of its preventive and therapeutic effects, which may be attributed to a variety of underlying mechanisms. However, data compiled by current studies are preliminary. Information about the molecular mechanism of dioscin remains limited, and no high-quality human experiments and clinical trials for testing its safety and efficacy have been conducted. As a resource for research in this area, this review is expected to provide a systematic framework for the application of dioscin in the treatment of diabetes mellitus and its complications.

Exploring the pharmacological versatility of ficus carica: Modulating classical immunometabolism and beyond

The burden of metabolic disorders is alarmingly increasing globally. On the other hand, sustainability is the key project of the 21st century. Natural products offer a coherent option for the complementary management of both these challenges. Ficus carica (FC), commonly known as the fig fruit, has an experimentally proven potency for the modulation of cell cycle, immunity, inflammation, metabolism, and oxidative stress. Here, we review the potential of FC-derived products (FCDP) in slowing down the progression of cancers, acute/chronic inflammation-related conditions, infections, metabolic disorders, toxicities, neurological and neuromuscular diseases, gastrointestinal disorders, vascular diseases, and skin-stressing conditions, as well as, in boosting normal healthy functions of the endocrine, immune, metabolic, and nervous systems. It reveals a variety of cellular and molecular targets for FCDP: cytokines (TNF-α, IL-1β, IL-6, IL-10, IL-12, IL-18, IFN-γ), chemokines (CCL2), other inflammatory mediators (CRP, PGE2), immune receptors (TLR-2, TLR-4, FcεRI), oxidative stress-related markers (SOD, GSH, MDA, GPx, catalase, ROS, NO, protein carbonyls), kinases (MAPKs, hexokinase, G6Pase, FBPase, PEPCK, Akt, AMPK, GSK3, CDKs), other enzymes (COX-2, iNOS, MMPs, caspases), growth factors/receptors (VEGF, EGFR), hormones (DHEAS, prolactin, GnRH, FSH, LH, estradiol, DHT, insulin), cell death-related markers (Bcl-2, Bax, Bak, FasL, gasdermins, cytochrome C), glucose transporter protein (Glut4), and transcription factors (NF-κB, HNF-4α, Foxo, PGC-1α, PPAR-γ, C/EBP-α, CREB, NFATC1, STAT3). FCDP cause both activation and inhibition of AMPK, MAPK, and NF-κB signaling to confer condition-specific advantages. Such a broad-range activity might be attributed to different mechanisms of action of FCDP in modulating functions within the classical immunometabolic system, but also beyond.

Rhythm and ROS: Hepatic Chronotherapeutic Features of Grape Seed Proanthocyanidin Extract Treatment in Cafeteria Diet-Fed Rats

Polyphenols play a key role in the modulation of circadian rhythms, while the cafeteria diet (CAF) is able to perturb the hepatic biological rhythm and induce important ROS production. Consequently, we aimed to elucidate whether grape seed proanthocyanidin extract (GSPE) administration recovers the CAF-induced hepatic antioxidant (AOX) misalignment and characterize the chronotherapeutic properties of GSPE. For this purpose, Fischer 344 rats were fed a standard diet (STD) or a CAF and concomitantly treated with GSPE at two time-points (ZT0 vs. ZT12). Animals were euthanized every 6 h and the diurnal rhythms of hepatic ROS-related biomarkers, hepatic metabolites, and AOX gene expression were examined. Interestingly, GSPE treatment was able to recover the diurnal rhythm lost due to the CAF. Moreover, GSPE treatment also increased the acrophase of Sod1, as well as bringing the peak closer to that of the STD group. GSPE also corrected some hepatic metabolites altered by the CAF. Importantly, the differences observed at ZT0 vs. ZT12 due to the time of GSPE administration highlight a chronotherapeutic profile on the proanthocyanin effect. Finally, GSPE could also reduce diet-induced hepatic oxidative stress not only by its ROS-scavenging properties but also by retraining the circadian rhythm of AOX enzymes.