Targeting innate immune mediators in type 1 and type 2 diabetes

Novel predictor of the occurrence of DKA in T1DM patients without infection: A combination of neutrophil/lymphocyte ratio and white blood cells

The role of inflammation has been identified in the pathogenesis of diabetic ketoacidosis (DKA). The neutrophil/lymphocyte ratio (NLR) and white blood cells (WBC) can be used to predict a systemic inflammatory response. Changes in NLR and WBC levels have never been explored in type 1 diabetes mellitus (T1DM) patients with DKA and an uninfected state. This retrospective study included a total of 644 participants. NLR and WBC were measured in the control group (n = 316) and in T1DM patients with mild-DKA (n = 92), severe-DKA (n = 52), and non-DKA (n = 184) in an uninfected state. Then, we assessed the independent predictors of DKA occurrence in T1DM patients in an uninfected state. The diagnostic performance of variables was determined by receiver operating characteristic curve analysis. Serum NLR of T1DM patients is significantly higher than that of normal controls, and if DKA occurs, NLR increases further and increases with the severity of DKA. In addition to diastolic blood pressure, blood urea nitrogen, glycated hemoglobin (HbA1c), and WBC, NLR was also independently associated with DKA in T1DM patients with an uninfected state (OR = 1.386, 95% CI: 1.127-1.705, p = 0.002). Furthermore, the diagnosis analysis showed that except for NLR and WBC, the area under the curve (AUC) of indicators with a statistical difference in patients with and without DKA were 0.747 for DKA diagnosis, and after the addition of NLR and WBC, the AUC was 0.806. The increased NLR level represents a low-cost and highly accessible predictor for DKA in T1DM patients with an uninfected state. The addition of inflammation indicators can play a statistically significant role in the prediction model of the DKA occurrence.

Heat-treated adzuki bean protein hydrolysates reduce obesity in mice fed a high-fat diet via remodeling gut microbiota and improving metabolic function

SCOPE

Heat-treated adzuki bean protein hydrolysates (APH) reduced cholesterol in vitro. However, it is unclear if APH have anti-obesity effects in vivo and, if so, the relationship between the effects and the improvement of gut microbiota composition and metabolic function.

METHODS AND RESULTS

Four groups of mice were fed either a normal control diet (NCD) or a high-fat diet (HFD) with or without APH for 12 weeks. In HFD-fed mice, APH supplementation significantly alleviated fat accumulation, dyslipidemia, insulin resistance, hepatic steatosis, and inflammation. In addition, APH supplementation regulated gut microbiota composition, reduced the abundance of harmful bacteria (Clostridium_sensu_stricto_1, Romboutsia, Blautia, Mucispirillum, Bilophila, and Peptococcus), enriched Lactobacillus and SCFA-producing bacteria (Lactobacillaceae, Eisenbergiella, Alistipes, Parabacteroides, Tannerellaceae, Eubacterium_nodatum_group, Acetatifactor, Rikenellaceae, and Odoribacter), and increased fecal SCFAs concentration. Importantly, APH supplementation significantly regulated the levels of serum metabolites, especially Lactobacillus-derived metabolites and tryptophan derivatives, which helped to alleviate obesity and its complications.

CONCLUSION

APH improved gut microbiota composition and metabolic function in mice and may help to prevent and treat obesity and related complications. This article is protected by copyright. All rights reserved.

Islet Autoimmunity is Highly Prevalent and Associated With Diminished β-Cell Function in Patients With Type 2 Diabetes in the Grade Study

Islet autoimmunity may contribute to β-cell dysfunction in type 2 diabetes (T2D). Its prevalence and clinical significance have not been rigorously determined. In this ancillary study to the Glycemia Reduction Approaches in Diabetes-A Comparative Effectiveness (GRADE) Study, we investigated the prevalence of cellular and humoral islet autoimmunity in patients with T2D duration 4·0±3·0 y, HbA1c 7·5±0·5% on metformin alone. We measured T cell autoreactivity against islet proteins, islet autoantibodies against GAD65, IA2, ZnT8, and β-cell function. Cellular islet autoimmunity was present in 41·3%, humoral islet autoimmunity in 13·5%, and both in 5·3%. β-cell function calculated as iAUC-CG and ΔC-peptide(0- 30)/Δglucose(0-30) from an oral glucose tolerance test was lower among T cell-positives (T+) than T cell-negatives (T-) using two different adjustments for insulin sensitivity (iAUC-CG: 13·2% [95% CI 0·3, 24·4%] or 11·4% [95% CI 0·4, 21·2%] lower; ΔC-peptide(0-30)/Δglucose(0-30)) 19% [95% CI 3·1, 32·3%] or 17·7% [95% CI 2·6, 30·5%] lower). T+ patients had 17% higher HbA1c (95% CI 0·07, 0·28) and 7·7 mg/dL higher fasting plasma glucose levels (95% CI 0·2,15·3) than T- patients. We conclude that islet autoimmunity is much more prevalent in T2D patients than previously reported. T cell-mediated autoimmunity is associated with diminished β-cell function and worse glycemic control.

The advanced glycation end-products (AGEs)/ROS/NLRP3 inflammasome axis contributes to delayed diabetic corneal wound healing and nerve regeneration

Diabetic keratopathy (DK) is an important diabetic complication at the ocular surface. Chronic low-grade inflammation mediated by the NLRP3 inflammasome promotes pathogenesis of diabetes and its complications. However, the effect of the NLRP3 inflammasome on DK pathogenesis remains elusive. Wild-type (WT) and Nlrp3 knockout (KO) C57 mice were used to establish a type I diabetes model by intraperitoneal injection of streptozotocin. The effect of the NLRP3 inflammasome on diabetic corneal wound healing and never regeneration was examined by a corneal epithelial abrasion model. Western blot, immunofluorescence staining, enzyme-linked immunosorbent assay (ELISA) and pharmacological treatment were performed to investigate the regulatory mechanism of advanced glycation end products (AGEs) on NLRP3 inflammasome activation and corneal wound healing in vivo. The cultured mouse corneal epithelial cells (TKE2) were used to evaluate the effect and mechanism of AGEs on NLRP3 inflammasome activation in vitro. We revealed that NLRP3 inflammasome-mediated inflammation and pyroptosis contributed to DK pathogenesis. Under physiological conditions, the NLRP3 inflammasome was required for corneal wound healing and nerve regeneration. However, under a diabetic scenario, sustained activation of the NLRP3 inflammasome resulted in postponed corneal wound healing and impaired nerve regeneration. Mechanistically, the accumulated AGEs promoted hyperactivation of the NLRP3 inflammasome through ROS production. Moreover, genetically and pharmacologically blocking the AGEs/ROS/NLRP3 inflammasome axis significantly expedited diabetic corneal epithelial wound closure and nerve regeneration. Our results revealed that AGEs-induced hyperactivation of the NLRP3 inflammasome resulted in delayed diabetic corneal wound healing and impaired nerve regeneration, which further highlighted the NLRP3 inflammasome as a promising target for DK treatment.

Metabolic Adaptions/Reprogramming in Islet Beta-Cells in Response to Physiological Stimulators—What Are the Consequences

Irreversible pancreatic β-cell damage may be a result of chronic exposure to supraphysiological glucose or lipid concentrations or chronic exposure to therapeutic anti-diabetic drugs. The β-cells are able to respond to blood glucose in a narrow concentration range and release insulin in response, following activation of metabolic pathways such as glycolysis and the TCA cycle. The β-cell cannot protect itself from glucose toxicity by blocking glucose uptake, but indeed relies on alternative metabolic protection mechanisms to avoid dysfunction and death. Alteration of normal metabolic pathway function occurs as a counter regulatory response to high nutrient, inflammatory factor, hormone or therapeutic drug concentrations. Metabolic reprogramming is a term widely used to describe a change in regulation of various metabolic enzymes and transporters, usually associated with cell growth and proliferation and may involve reshaping epigenetic responses, in particular the acetylation and methylation of histone proteins and DNA. Other metabolic modifications such as Malonylation, Succinylation, Hydroxybutyrylation, ADP-ribosylation, and Lactylation, may impact regulatory processes, many of which need to be investigated in detail to contribute to current advances in metabolism. By describing multiple mechanisms of metabolic adaption that are available to the β-cell across its lifespan, we hope to identify sites for metabolic reprogramming mechanisms, most of which are incompletely described or understood. Many of these mechanisms are related to prominent antioxidant responses. Here, we have attempted to describe the key β-cell metabolic adaptions and changes which are required for survival and function in various physiological, pathological and pharmacological conditions.

The role of interleukin-1β in type 2 diabetes mellitus: A systematic review and meta-analysis

Type 2 diabetes mellitus (T2DM) is a multifactorial non-communicable disease that is characterized by insulin resistance and chronic sub-clinical inflammation. Among the emerging inflammatory markers observed to be associated with β-cell damage is interleukin 1β (IL1β), a proinflammatory cytokine that modulates important metabolic processes including insulin secretion and β-cell apoptosis. The present systematic review and meta-analysis gathers available evidence on the emerging role of IL1β in T2DM. PubMed and Embase were searched for human studies that assessed 1L1β in T2DM individuals from 2016-2021. Thirteen studies (N=2680; T2DM=1182, controls=1498) out of 523 were included in the systematic review and only 3 studies in the meta-analysis. Assays were the most commonly used quantification method and lipopolysaccharides as the most common stimulator for IL1β upregulation. Random and fixed effects meta-analysis showed non-significant mean differences of IL1β concentrations between the T2DM and controls. Given the high heterogeneity and small subset of studies included, caution is advised in the interpretation of results. The present systematic review and meta-analysis highlights the limited evidence available that could implicate 1L1β as a potent biomarker for T2DM. Standardization of 1L1β assays with larger sample sizes are encouraged in future observational and prospective studies.

Mechanistic investigations of diabetic ocular surface diseases

With the global prevalence of diabetes mellitus over recent decades, more patients suffered from various diabetic complications, including diabetic ocular surface diseases that may seriously affect the quality of life and even vision sight. The major diabetic ocular surface diseases include diabetic keratopathy and dry eye. Diabetic keratopathy is characterized with the delayed corneal epithelial wound healing, reduced corneal nerve density, decreased corneal sensation and feeling of burning or dryness. Diabetic dry eye is manifested as the reduction of tear secretion accompanied with the ocular discomfort. The early clinical symptoms include dry eye and corneal nerve degeneration, suggesting the early diagnosis should be focused on the examination of confocal microscopy and dry eye symptoms. The pathogenesis of diabetic keratopathy involves the accumulation of advanced glycation end-products, impaired neurotrophic innervations and limbal stem cell function, and dysregulated growth factor signaling, and inflammation alterations. Diabetic dry eye may be associated with the abnormal mitochondrial metabolism of lacrimal gland caused by the overactivation of sympathetic nervous system. Considering the important roles of the dense innervations in the homeostatic maintenance of cornea and lacrimal gland, further studies on the neuroepithelial and neuroimmune interactions will reveal the predominant pathogenic mechanisms and develop the targeting intervention strategies of diabetic ocular surface complications.

Latent Autoimmune Diabetes in Adults (LADA): From Immunopathogenesis to Immunotherapy

Latent autoimmune diabetes in adults (LADA) is a type of diabetes characterized by slow autoimmune damage of pancreatic β cells without insulin treatment in the early clinical stage. There are differences between LADA and classical type 1 diabetes (T1D) and type 2 diabetes (T2D) in genetic background, autoimmune response, rate of islet function decline, clinical metabolic characteristics, and so on. The disease progression and drug response of patients with LADA are closely related to the level of islet autoimmunity, thus exploring the pathogenesis of LADA is of great significance for its prevention and treatment. Previous studies reported that adaptive immunity and innate immunity play a critical role in the etiology of LADA. Recent studies have shown that the intestinal microbiota which impacts host immunity hugely, participates in the pathogenesis of LADA. In addition, the progression of autoimmune pancreatic β cell destruction in LADA is slower than in classical T1D, providing a wider window of opportunities for intervention. Therefore, therapies including antidiabetic drugs with immune-regulation effects and immunomodulators could contribute to promising interventions for LADA. We also shed light on potential interventions targeting the gut microbiota and gut-associated immunity, which may be envisaged to halt or delay the process of autoimmunity in LADA.

Increased incidence of genital warts among women and men with type 1 diabetes compared with the general population-results from a nationwide registry-based, cohort study

AIMS

To estimate the incidence rates of genital warts (GWs) in women and men with type 1 diabetes compared to persons without diabetes.

METHODS

In this nationwide registry-based cohort study, we included the entire population aged 15 to 49 years living in Denmark between 1996 and 2016. From national registries, we retrieved individual level information on diabetes status, diagnoses and treatment of GWs, and potential confounding variables. We used Poisson regression to model sex- and age-specific incidence rates of GWs in persons with type 1 diabetes and persons without diabetes. Based on the models, we computed sex-specific incidence rate ratios (IRRs) of GWs in persons with type 1 diabetes compared to persons without diabetes, overall and according to age.

RESULTS

The analysis included 3,514,824 persons without type 2 diabetes and no GW diagnoses before baseline. The incidence rate of GWs in persons with type 1 diabetes was higher than in those without diabetes, both among women (IRR = 1.59; 95% CI, 1.42-1.78) and men (IRR = 1.36; 95% CI, 1.25-1.48). The pattern of increased incidence rates of GWs in persons with type 1 diabetes was seen at all ages.

CONCLUSIONS

Persons with type 1 diabetes have higher incidence rates of GWs than persons without diabetes. This supports the importance of HPV vaccination of young girls and boys with type 1 diabetes.

RHEUMATOID ARTHRITIS AS A PREDISPOSING FACTOR FOR INCREASED RISK OF DIABETES MELLITUS INCIDENCE

OBJECTIVE

The aim: Recent advances in diabetic mellitus (DM) care are focusing emphasis on comorbidities including rheumatoid arthritis (RA). The goal of this study is to determine the relationship between RA and diabetes as a risk factor.

PATIENTS AND METHODS

Materials and methods: Participants whose diagnosis of RA was confirmed by rheumatologists were recruited into a cross-sectional observational cohort using data from government and private clinics. Participants filled out detailed questionnaires. We included patients with DM and combined DM and RA who was diagnosed with both conditions by specialists between (October 2021 to April 2022) in Al Kut city, Iraq.

RESULTS

Results: Our finding shows no difference between the two groups DM and DM+RA in age, BMI, and smoking. However, the health status represented by hospitalization was more frequent in the DM+RA group. The inflammatory pathway in RA also increases the incidence of DM where we show an increase in the ESR in the DM+RA group. Interestingly Glycated hemoglobin (Hb a1c) indicator of DM was significantly increased in DM+RA compared to the DM group.

CONCLUSION

Conclusions: In conclusion, RA is linked to an increased chance of developing diabetes. This data backs up the theory that inflammatory pathways play a role in diabetes development.

Islet Inflammation and β Cell Dysfunction in Type 2 Diabetes

Pancreatic islets are the body's central rheostat that regulates glucose homeostasis through the production of different hormones, including β cell-derived insulin. During obesity-induced type 2 diabetes (T2D), islet β cells become dysfunctional and inadequate insulin secretion no longer ensures glycemic control. T2D is associated with a chronic low-grade inflammation that manifests in several metabolic organs including the pancreatic islets. Growing evidence suggests that components of the innate immune system, and especially macrophages, play a crucial role in regulating islet homeostasis. Yet, the phenotypes and functions of islet macrophages in physiology and during T2D have only started to attract attention and remain unclear. In this review, the current knowledge about islet inflammation and macrophages will be summarized in humans and rodent models. Recent findings on the cellular and molecular mechanisms involved in islet remodeling and β cell function during obesity and T2D will be discussed.

Emerging Roles of Myeloid-Derived Suppressor Cells in Diabetes

Diabetes is a syndrome characterized by hyperglycemia with or without insulin resistance. Its etiology is attributed to the combined action of genes, environment and immune cells. Myeloid-derived suppressor cell (MDSC) is a heterogeneous population of immature cells with immunosuppressive ability. In recent years, different studies have debated the quantity, activity changes and roles of MDSC in the diabetic microenvironment. However, the emerging roles of MDSC have not been fully documented with regard to their interactions with diabetes. Here, the manifestations of MDSC and their subsets are reviewed with regard to the incidence of diabetes and diabetic complications. The possible drugs targeting MDSC are discussed with regard to their potential of treating diabetes. We believe that understanding MDSC will offer opportunities to explain pathological characteristics of different diabetes. MDSC also will be used for personalized immunotherapy of diabetes.

The role and research progress of the balance and interaction between regulatory T cells and other immune cells in obesity with insulin resistance

Metabolic homoeostasis in adipose tissue plays a major role in obesity-related insulin resistance (IR). Regulatory T (Treg) cells have been recorded to regulate metabolic homoeostasis in adipose tissue. However, their specific mechanism is not yet known. This review aims to present the role of Treg cells and other immune cells in obesity-associated IR, focusing on the balance of numbers and functions of Treg cells and other immune cells as well as the crucial role of their interactions in maintaining adipose tissue homoeostasis. Th1 cells, Th17 cells, CD8⁺ T cells, and pro-inflammatory macrophages mediate the occurrence of obesity and IR by antagonizing Treg cells, while anti-inflammatory dendritic cells, eosinophils and type 2 innate lymphoid cells (ILC2s) regulate the metabolic homoeostasis of adipose tissue by promoting the proliferation and differentiation of Treg cells. γ δ T cells and invariant natural killer T (iNKT) cells have complex effects on Treg cells, and their roles in obesity-associated IR are controversial. The balance of Treg cells and other immune cells can help maintain the metabolic homoeostasis of adipose tissue. Further research needs to explore more specific molecular mechanisms, thus providing more precise directions for the treatment of obesity with IR.

The epidemiology, pathophysiological mechanisms, and management toward COVID-19 patients with Type 2 diabetes: A systematic review

This review comprehensively summarizes epidemiologic evidence of COVID-19 in patients with Type 2 diabetes, explores pathophysiological mechanisms, and integrates recommendations and guidelines for patient management. We found that diabetes was a risk factor for diagnosed infection and poor prognosis of COVID-19. Patients with diabetes may be more susceptible to adverse outcomes associated with SARS-CoV-2 infection due to impaired immune function and possible upregulation of enzymes that mediate viral invasion. The chronic inflammation caused by diabetes, coupled with the acute inflammatory reaction caused by SARS-CoV-2, results in a propensity for inflammatory storm. Patients with diabetes should be aware of their increased risk for COVID-19.

Overexpression of E3 ubiquitin ligase Cbl attenuates endothelial dysfunction in diabetes mellitus by inhibiting the JAK2/STAT4 signaling and Runx3-mediated H3K4me3

BACKGROUND

Diabetes mellitus (DM), a most common chronic disease, is featured with impaired endothelial function and bioavailability of nitric oxide (NO), while E3 ubiquitin ligase appears to alleviate endothelial dysfunction as a promising option for DM treatment. Herein, we aimed to determine whether E3 ubiquitin ligase casitas B-lineage lymphoma (Cbl) alleviates endothelial dysfunction in DM rats by JAK2/STAT4 pathway.

METHODS

A rat model of DM was developed through intraperitoneal injection of streptozotocin, followed by collection of aortic tissues to determine the expression of Cbl, JAK2, runt-related transcription factor 3 (Runx3) and STAT4. Human umbilical vein endothelial cells (HUVECs) were cultured in high glucose (HG) condition to induce DM as an in vitro model. With gain- and loss-function method, we assessed the aberrantly expressed Cb1 on endothelial dysfunction, NO production and apoptosis of HUVECs.

RESULTS

Cbl was reduced in DM rat tissues and HG-induced HUVECs, where JAK2, Runx3 and STAT4 were elevated. It was found that overexpression of Cbl alleviated endothelial dysfunction by increasing NO production and restoring vasodilation and suppressing apoptosis of HUVECs. Mechanistically, Cb1 enhanced JAK2 ubiquitination and decreased JAK2 and STAT4 expression, where STAT4 improved Runx3 expression by regulating histone H3 lysine 4 trimethylation level. Overexpression of JAK2 and STAT4, or Runx3 increased apoptosis of HUVECs, abrogating the effect of Cb1 on endothelial function.

CONCLUSION

In conclusion, Cbl alleviates endothelial dysfunction by inactivation of the JAK2/STAT4 pathway and inhibition of Runx3 expression in DM. These evidence might underlie novel Cbl-based treatment against DM in the future.

Anti-IAPP Monoclonal Antibody Improves Clinical Symptoms in a Mouse Model of Type 2 Diabetes

Type 2 Diabetes Mellitus (T2DM) is a chronic progressive disease, defined by insulin resistance and insufficient insulin secretion to maintain normoglycemia. Amyloidogenic aggregates are a hallmark of T2DM patients; they are cytotoxic for the insulin producing β-cells, and cause inflammasome-dependent secretion of IL-1β. To avoid the associated β-cell loss and inflammation in advanced stage T2DM, we developed a novel monoclonal therapy targeting the major component of aggregates, islet amyloid polypeptide (IAPP). The here described monoclonal antibody (mAb) m81, specific for oligomeric and fibrils, but not for soluble free IAPP, is able to prevent oligomer growth and aggregate formation in vitro, and blocks islet inflammation and disease progression in vivo. Collectively, our data show that blocking fibril formation and prevention of new amyloidogenic aggregates by monoclonal antibody therapy may be a potential therapy for T2DM.

Elevated branched-chain α-keto acids exacerbate macrophage oxidative stress and chronic inflammatory damage in type 2 diabetes mellitus

AIMS

Chronic inflammation is a primary reason for type 2 diabetes mellitus (T2DM) and its complications, while disordered branched-chain amino acids (BCAA) metabolism is found in T2DM, but the link between BCAA catabolic defects and inflammation in T2DM remains elusive and needs to be investigated.

METHODS

The changes in BCAA catabolism, inflammation, organ damage, redox status, and mitochondrial function in db/db mice with treatments of BCAA-overload or BCAA catabolism activator were analyzed in vivo. The changes in BCAA catabolic metabolism, as well as the direct effects of BCAAs/branched-chain alpha-keto acids (BCKAs) on cytokine release and redox status were also analyzed in primary macrophages in vitro.

RESULTS

Inactivation of branched-chain ɑ-ketoacid dehydrogenase (BCKDH) complex was found in multiple organs (liver, muscle and kidney) of db/db mice. Long-term high BCAA supplementation further increased BCKA levels, inflammation, tissue fibrosis (liver and kidney), and macrophage hyper-activation in db/db mice, while enhancing BCAA catabolism with pharmacological activator reduced these adverse effects in db/db mice. In vitro, the BCAA catabolism was unchanged in primary macrophages of db/db mice, and elevated BCKAs but not BCAAs promoted the cytokine production in primary macrophages. Moreover, BCKA stimulation was associated with increased mitochondrial oxidative stress and redox imbalance in macrophages and diabetic organs.

CONCLUSION

Impaired BCAA catabolism is strongly associated with chronic inflammation and tissue damage in T2DM, and this effect is at least partly due to the BCKAs-induced macrophage oxidative stress. This study highlights that targeting BCAA catabolism is a potential strategy to attenuate T2DM and its complications.

Role of stilbenes against insulin resistance: A review

Insulin resistance (IR) is a state characterized by the inability of tissues to utilize blood glucose particularly liver, muscle, and adipose tissues resulting in hyperglycemia and hyperinsulinemia. A close relationship exists between IR and the development of type 2 diabetes (T2D). Therefore, therapeutic approaches to treat IR also improve T2D simultaneously. Scientific evidence has highlighted the major role of inflammatory cytokines, reactive oxygen species (ROS), environmental & genetic factors, and auto-immune disorders in the pathophysiology of IR. Among therapeutic remedies, nutraceuticals like polyphenols are being used widely to ameliorate IR due to their safer nature compared to pharmaceutics. Stilbenes are considered important metabolically active polyphenols currently under the limelight of research to cope with IR. In this review, efforts are made to elucidate cellular and subcellular mechanisms influenced by stilbenes including modulating insulin signaling cascade, correcting glucose transport pathways, lowering postprandial glucose levels, and protecting β-cell damage and its effects on the hyperactive immune system and proinflammatory cytokines to attenuate IR. Furthermore, future directions to further the research in stilbenes as a strong candidate against IR are included so that concrete recommendation for their use in humans is made.

Berberine ameliorates erectile dysfunction in rats with streptozotocin-induced diabetes mellitus through the attenuation of apoptosis by inhibiting the SPHK1/S1P/S1PR2 and MAPK pathways

BACKGROUND

The population with diabetes mellitus-induced erectile dysfunction is increasing rapidly, but current drugs are not effective in treating erectile dysfunction. Studies of the traditional Chinese medicine extract berberine on diabetes and its complications provide us with new ideas.

OBJECTIVES

To evaluate the therapeutic effect and potential mechanism of berberine on the erectile function of diabetic rats.

MATERIALS AND METHODS

Fifty male Sprague-Dawley rats were randomly grouped, and 42 rats were injected intraperitoneally with streptozotocin to establish a diabetes model. Erectile dysfunction rats were screened out through the apomorphine test and randomly divided into the diabetes mellitus and berberine groups, and these animals were administered berberine (200 mg/kg/day) and normal saline by gavage for 4 weeks. Primary corpus cavernous smooth muscle cells from healthy rats were cultured and treated with berberine.

RESULTS

Fasting blood glucose in the diabetes mellitus group was significantly increased, while berberine showed no significant effect on glucose. Erectile function was obviously impaired in the diabetes mellitus group, and berberine administration partially rescued this impairment. The expression of sphingosine kinase 1, S1PR2, and sphingosine-1-phosphate in the diabetes mellitus group was increased. Berberine partially inhibited the expression of sphingosine kinase 1 and S1PR2, but the decrease in sphingosine-1-phosphate was not significant. Moreover, mitogen-activated protein kinase pathway factor expression was upregulated and eNOS activity was decreased in the diabetes mellitus group. Berberine treatment could partially reverse these alterations. Severe fibrosis and apoptosis were detected in diabetic rats, accompanied by higher expression of TGFβ1, collagen I/IV, Bax/Bcl-2, and caspase 3 than in the other groups. However, supplementation with berberine inhibited the expression of these proteins and attenuated fibrosis and apoptosis.

CONCLUSIONS

Berberine ameliorated erectile dysfunction in rats with diabetes mellitus, possibly by improving endothelial function and inhibiting apoptosis and fibrosis by suppressing the sphingosine kinase 1/sphingosine-1-phosphate/S1PR2 and mitogen-activated protein kinase pathways.

Platelet Mediated Inflammation in Coronary Artery Disease with Type 2 Diabetes Patients

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a well-established risk factor for the development of atherosclerotic coronary artery disease. Platelet hyperactivity and inflammation are associated with the development of coronary artery disease (CAD) in T2DM patients. We investigated the status of immune cells, platelet activation, and platelet-immune cell interactions in T2DM_CAD patients.

METHODOLOGY

The study population consisted of four groups of subjects, healthy control (CT, n = 20), T2DM (n = 44), CAD (n = 20) and T2DM_CAD (n = 38). Platelet activation, immunome profiling and platelet-immune cell interactions were analysed by flow cytometry. The circulatory levels of inflammatory cytokines/chemokines were assessed using multiplex assay.

RESULTS

Increased platelet activation and increased platelet-immune cell aggregate formation were observed in T2DM and T2DM_CAD groups compared to the control and CAD groups (p < 0.05). Our immunome profile analysis revealed, altered monocyte subpopulations and dendritic cell populations in T2DM, CAD and T2DM_CAD groups compared to the control group (p < 0.05). Furthermore, significantly increased IL-1β, IL-2, IL-4, IL-6, IL-8, IL12p70, IL-13 IL-18, CCL2, and decreased CXCL1, CCL5 levels were observed in T2DM_CAD group compared to the control group. Our ex-vivo study increased platelet-monocyte aggregate formation was observed upon D-glucose exposure in a time and concentration dependent manner.

CONCLUSION

Our data suggests that T2DM, CAD and T2DM_CAD are associated with altered immune cell populations. Furthermore, it has been confirmed that hyperglycemia induces platelet activation and forms platelet-immune cell aggregation which may lead to the release of inflammatory cytokines and chemokines and contribute to the complexity of CAD and type 2 diabetes.

The Link Between Periodontal Inflammation and Obesity

Purpose of Review

Obesity is a trigger for multiple diseases such as diabetes mellitus, hypertension, and cardiovascular diseases. Epidemiological studies have shown that obesity may be a risk factor for periodontal disease. Recently, there have been reports of presumed mechanisms of the associations between periodontitis and lipid metabolism or thermogenesis. This review aims to discuss the link between periodontal disease and energy regulatory function based on recent findings.

Recent Findings

It has been demonstrated that activation of the C–C motif chemokine ligand/C–C chemokine receptor 7 pathway in adipose tissue induces inflammation and impairment of lipid metabolism and energy regulation in mice. Porphyromonas gingivalis administration has been shown to induce further weight gain and increased adipose tissue in diet-induced obese mice. Additionally, it has been reported that Porphyromonas gingivalis–induced endotoxemia potentially affect obesity by altering endocrine functions in brown adipose tissue in mice. Several cohort studies have shown that obesity is associated with tooth loss 5 years later, and periodontal conditions of obese individuals are significantly worse 2 and 6 months after the treatment compared with those of non-obese individuals. It has also been reported that body mass index is positively associated with the periodontal inflamed surface area index, a measure of periodontal inflammation. These results suggest that not only the enhancement of inflammation due to obesity but also the activation of inflammatory signaling may affect energy regulation.

Summary

Loss of adipose tissue homeostasis induces increase and activation of immune cells in adipose tissue, leading to impaired immune function in obesity. Various cytokines and chemokines are secreted from obese adipose tissue and promote inflammatory signaling. Some of these signaling pathways have been suggested to affect energy regulation. The combination of obesity and periodontitis amplifies inflammation to levels that affect the whole body through the adipose tissue. Obesity, in turn, accelerates the exacerbation of periodontitis.

The β Cell in Diabetes: Integrating Biomarkers With Functional Measures

The pathogenesis of hyperglycemia observed in most forms of diabetes is intimately tied to the islet β cell. Impairments in propeptide processing and secretory function, along with the loss of these vital cells, is demonstrable not only in those in whom the diagnosis is established but typically also in individuals who are at increased risk of developing the disease. Biomarkers are used to inform on the state of a biological process, pathological condition, or response to an intervention and are increasingly being used for predicting, diagnosing, and prognosticating disease. They are also proving to be of use in the different forms of diabetes in both research and clinical settings. This review focuses on the β cell, addressing the potential utility of genetic markers, circulating molecules, immune cell phenotyping, and imaging approaches as biomarkers of cellular function and loss of this critical cell. Further, we consider how these biomarkers complement the more long-established, dynamic, and often complex measurements of β-cell secretory function that themselves could be considered biomarkers.

No Casual Relationship Between T2DM and the Risk of Infectious Diseases: A Two-Sample Mendelian Randomization Study

Background

In epidemiological studies, it has been proven that the occurrence of type 2 diabetes mellitus (T2DM) is related to an increased risk of infectious diseases. However, it is still unclear whether the relationship is casual.

Methods

We employed a two-sample Mendelian randomization (MR) to clarify the causal effect of T2DM on high-frequency infectious diseases: sepsis, skin and soft tissue infections (SSTIs), urinary tract infections (UTIs), pneumonia, and genito-urinary infection (GUI) in pregnancy. And then, we analyzed the genome-wide association study (GWAS) meta-analysis of European-descent individuals and conducted T2DM-related single-nucleotide polymorphisms (SNPs) as instrumental variables (IVs) that were associated with genome-wide significance (p < 5 × 10^–8). MR estimates were obtained using the inverse variance-weighted (IVW), the MR-Egger regression, the simple mode (SM), weighted median, and weighted mode.

Results

The UK Biobank (UKB) cohort (n > 500,000) provided data for GWASs on infectious diseases. MR analysis showed little evidence of a causal relationship of T2DM with five mentioned infections’ (sepsis, SSTI, UTI, pneumonia, and GUI in pregnancy) susceptibility [odds ratio (OR) = 0.99999, p = 0.916; OR = 0.99986, p = 0.233; OR = 0.99973, p = 0.224; OR = 0.99997, p = 0.686; OR, 1.00002, p = 0.766]. Sensitivity analysis showed similar results, indicating the robustness of causality. There were no heterogeneity and pleiotropic bias.

Conclusion

T2DM would not be causally associated with high-frequency infectious diseases (including sepsis, SSTI, UTI, pneumonia, and GUI in pregnancy).

Chronic tissue inflammation and metabolic disease

In this review, Lee and Olefsky discuss the characteristics of chronic inflammation in the major metabolic tissues and how obesity triggers these events, including a focus on the role of adipose tissue hypoxia and macrophage-derived exosomes.

Obesity is the most common cause of insulin resistance, and the current obesity epidemic is driving a parallel rise in the incidence of T2DM. It is now widely recognized that chronic, subacute tissue inflammation is a major etiologic component of the pathogenesis of insulin resistance and metabolic dysfunction in obesity. Here, we summarize recent advances in our understanding of immunometabolism. We discuss the characteristics of chronic inflammation in the major metabolic tissues and how obesity triggers these events, including a focus on the role of adipose tissue hypoxia and macrophage-derived exosomes. Last, we also review current and potential new therapeutic strategies based on immunomodulation.

Type 2 Innate Lymphoid Cells: Protectors in Type 2 Diabetes

Type 2 innate lymphoid cells (ILC2) are the innate counterparts of Th2 cells and are critically involved in the maintenance of homeostasis in a variety of tissues. Instead of expressing specific antigen receptors, ILC2s respond to external stimuli such as alarmins released from damage. These cells help control the delicate balance of inflammation in adipose tissue, which is a determinant of metabolic outcome. ILC2s play a key role in the pathogenesis of type 2 diabetes mellitus (T2DM) through their protective effects on tissue homeostasis. A variety of crosstalk takes place between resident adipose cells and ILC2s, with each interaction playing a key role in controlling this balance. ILC2 effector function is associated with increased browning of adipose tissue and an anti-inflammatory immune profile. Trafficking and maintenance of ILC2 populations are critical for tissue homeostasis. The metabolic environment and energy source significantly affect the number and function of ILC2s in addition to affecting their interactions with resident cell types. How ILC2s react to changes in the metabolic environment is a clear determinant of the severity of disease. Treating sources of metabolic instability via critical immune cells provides a clear avenue for modulation of systemic homeostasis and new treatments of T2DM.

Visceral Adipose Tissue: A New Target Organ in Virus-Induced Type 1 Diabetes

Type 1 diabetes (T1D) is a proinflammatory pathology that leads to the specific destruction of insulin producing β-cells and hyperglycaemia. Much of the knowledge about type 1 diabetes (T1D) has focused on mechanisms of disease progression such as adaptive immune cells and the cytokines that control their function, whereas mechanisms linked with the initiation of the disease remain unknown. It has been hypothesized that in addition to genetics, environmental factors play a pivotal role in triggering β-cell autoimmunity. The BioBreeding Diabetes Resistant (BBDR) and LEW1.WR1 rats have been used to decipher the mechanisms that lead to virus-induced T1D. Both animals develop β-cell inflammation and hyperglycemia upon infection with the parvovirus Kilham Rat Virus (KRV). Our earlier in vitro and in vivo studies indicated that KRV-induced innate immune upregulation early in the disease course plays a causal role in triggering β-cell inflammation and destruction. Furthermore, we recently found for the first time that infection with KRV induces inflammation in visceral adipose tissue (VAT) detectable as early as day 1 post-infection prior to insulitis and hyperglycemia. The proinflammatory response in VAT is associated with macrophage recruitment, proinflammatory cytokine and chemokine upregulation, endoplasmic reticulum (ER) and oxidative stress responses, apoptosis, and downregulation of adipokines and molecules that mediate insulin signaling. Downregulation of inflammation suppresses VAT inflammation and T1D development. These observations are strikingly reminiscent of data from obesity and type 2 diabetes (T2D) in which VAT inflammation is believed to play a causal role in disease mechanisms. We propose that VAT inflammation and dysfunction may be linked with the mechanism of T1D progression.

Selenium Deficiency Due to Diet, Pregnancy, Severe Illness, or COVID-19-A Preventable Trigger for Autoimmune Disease

The trace element selenium (Se) is an essential part of the human diet; moreover, increased health risks have been observed with Se deficiency. A sufficiently high Se status is a prerequisite for adequate immune response, and preventable endemic diseases are known from areas with Se deficiency. Biomarkers of Se status decline strongly in pregnancy, severe illness, or COVID-19, reaching critically low concentrations. Notably, these conditions are associated with an increased risk for autoimmune disease (AID). Positive effects on the immune system are observed with Se supplementation in pregnancy, autoimmune thyroid disease, and recovery from severe illness. However, some studies reported null results; the database is small, and randomized trials are sparse. The current need for research on the link between AID and Se deficiency is particularly obvious for rheumatoid arthritis and type 1 diabetes mellitus. Despite these gaps in knowledge, it seems timely to realize that severe Se deficiency may trigger AID in susceptible subjects. Improved dietary choices or supplemental Se are efficient ways to avoid severe Se deficiency, thereby decreasing AID risk and improving disease course. A personalized approach is needed in clinics and during therapy, while population-wide measures should be considered for areas with habitual low Se intake. Finland has been adding Se to its food chain for more than 35 years-a wise and commendable decision, according to today's knowledge. It is unfortunate that the health risks of Se deficiency are often neglected, while possible side effects of Se supplementation are exaggerated, leading to disregard for this safe and promising preventive and adjuvant treatment options. This is especially true in the follow-up situations of pregnancy, severe illness, or COVID-19, where massive Se deficiencies have developed and are associated with AID risk, long-lasting health impairments, and slow recovery.

Inhibition of PHLPP1/2 phosphatases rescues pancreatic β-cells in diabetes

Pancreatic β-cell failure is the key pathogenic element of the complex metabolic deterioration in type 2 diabetes (T2D); its underlying pathomechanism is still elusive. Here, we identify pleckstrin homology domain leucine-rich repeat protein phosphatases 1 and 2 (PHLPP1/2) as phosphatases whose upregulation leads to β-cell failure in diabetes. PHLPP levels are highly elevated in metabolically stressed human and rodent diabetic β-cells. Sustained hyper-activation of mechanistic target of rapamycin complex 1 (mTORC1) is the primary mechanism of the PHLPP upregulation linking chronic metabolic stress to ultimate β-cell death. PHLPPs directly dephosphorylate and regulate activities of β-cell survival-dependent kinases AKT and MST1, constituting a regulatory triangle loop to control β-cell apoptosis. Genetic inhibition of PHLPPs markedly improves β-cell survival and function in experimental models of diabetes in vitro, in vivo, and in primary human T2D islets. Our study presents PHLPPs as targets for functional regenerative therapy of pancreatic β cells in diabetes.

Activation of Peripheral Blood Mononuclear Cells and Leptin Secretion: New Potential Role of Interleukin-2 and High Mobility Group Box (HMGB)1

Activation of innate immunity and low-grade inflammation contributes to hyperglycemia and an onset of Type 2 Diabetes Mellitus (T2DM). Interleukin-2 (IL-2), leptin, High Mobility Group Box-1 (HMGB-1), and increased glucose concentrations are mediators of these processes also by modulating peripheral blood mononuclear cells (PBMCs) response. The aim of this study was to investigate if HMGB-1 and IL-2 turn on PBMCs and their leptin secretion. In isolated human PBMCs and their subpopulations from healthy individuals and naïve T2DM patients, leptin release, pro-inflammatory response and Toll-like Receptors (TLRs) activation was measured. After treatment with IL-2 and HMGB1, NK (Natural Killer) have the highest amount of leptin secretion, whilst NK-T have the maximal release in basal conditions. TLR4 (TAK242) and/or TLR2 (TLR2-IgA) inhibitors decreased leptin secretion after IL-2 and HMGB1 treatment. A further non-significant increase in leptin secretion was reported in PBMCs of naive T2DM patients in response to IL-2 and HMGB-1 stimulation. Finally, hyperglycemia or hyperinsulinemia might stimulate leptin secretion from PBMCs. The amount of leptin released from PBMCs after the different treatments was enough to stimulate the secretion of IL-1β from monocytes. Targeting leptin sera levels and secretion from PBMCs could represent a new therapeutic strategy to counteract metabolic diseases such as T2DM.

Hsa_circ_0054633 association of C peptide is related to IL-17 and TNF-α in patients with diabetes mellitus receiving insulin treatment

Background

Chronic inflammation damaged the islet and resulted in dysfunction of T2D. Circular RNA is stable and better for biomarker in many diseases. Here, we aimed to identify potential circular RNA hsa_circ_0054633 that can be a biomarkers for the effects of insulin therapy in T2D.

Methods

In this retrospective case‐control study, patients were from Li Huili Hospital, Ningbo, China, from February 10, 2019, to August 15, 2019. We included 47 healthy adults, 46 new‐onset T2D with insulin resistance, and 51 patients with insulin therapy. Serum inflammation factors were tested by ELISA assays. We selected hsa_circ_0054633 as a candidate biomarker and measured its concentration in serum by qRT‐PCR. The Pearson correlation test was used to evaluate the correlation between this circRNA and clinical variables.

Results

Clinical data indicated that serum C peptide was increased in T2D treatment with insulin. Serum hsa_circ_0054633 was decreased in insulin treatment group. Hsa_circ_0054633 was negative correlated with C peptide (r = −0.2841, p = 0.0433,). IL‐1 and IL‐6, IL‐17, and TNF‐α were higher in T2D patients and decreased after insulin treatment, only IL‐17 and TNF‐α showed a positive correlation to hsa_circ_0054633 (r = 0.4825, p < 0.0001, and r = 0.6190, p < 0.0001). The area under ROC curve was 0.7432, 0.5839, and 0.7573 for Hsa_circ_0054633, C peptide, and their combination.

Conclusion

Hsa_circ_0054633 level was lower in T2D with insulin treatment than untreated and was a negative correlation with C peptide, and positively correlated with IL‐17 and TNF‐α, suggesting that hsa_circ_0054633 may be a potential early indicator of insulin treatment effect to improve inflammation condition.

New Aspects of Diabetes Research and Therapeutic Development

Both type 1 and type 2 diabetes mellitus are advancing at exponential rates, placing significant burdens on health care networks worldwide. Although traditional pharmacologic therapies such as insulin and oral antidiabetic stalwarts like metformin and the sulfonylureas continue to be used, newer drugs are now on the market targeting novel blood glucose-lowering pathways. Furthermore, exciting new developments in the understanding of beta cell and islet biology are driving the potential for treatments targeting incretin action, islet transplantation with new methods for immunologic protection, and the generation of functional beta cells from stem cells. Here we discuss the mechanistic details underlying past, present, and future diabetes therapies and evaluate their potential to treat and possibly reverse type 1 and 2 diabetes in humans. SIGNIFICANCE STATEMENT: Diabetes mellitus has reached epidemic proportions in the developed and developing world alike. As the last several years have seen many new developments in the field, a new and up to date review of these advances and their careful evaluation will help both clinical and research diabetologists to better understand where the field is currently heading.

The Role of Interleukin-1β in Destruction of Transplanted Islets

Islet transplantation is a promising β-cell replacement therapy for type 1 diabetes, which can reduce glucose lability and hypoglycemic episodes compared with standard insulin therapy. Despite the tremendous progress made in this field, challenges remain in terms of long-term successful transplant outcomes. The insulin independence rate remains low after islet transplantation from one donor pancreas. It has been reported that the islet-related inflammatory response is the main cause of early islet damage and graft loss after transplantation. The production of interleukin-1β (IL-1β) has considered to be one of the primary harmful inflammatory events during pancreatic procurement, islet isolation, and islet transplantation. Evidence suggests that the innate immune response is upregulated through the activity of Toll-like receptors and The NACHT Domain-Leucine-Rich Repeat and PYD-containing Protein 3 inflammasome, which are the starting points for a series of signaling events that drive excessive IL-1β production in islet transplantation. In this review, we show recent contributions to the advancement of knowledge of IL-1β in islet transplantation and discuss several strategies targeting IL-1β for improving islet engraftment.

MCPIP1 is a novel link between diabetogenic conditions and impaired insulin secretory capacity

During diabetes development insulin production and glucose-stimulated insulin secretion (GSIS) are defective due to inflammation-related, yet not fully understood mechanisms. MCPIP1 (monocyte chemotactic protein-induced protein-1) is a strong regulator of inflammation, and acts predominantly as a specific RNase. The impact of MCPIP1 on insulin secretory capacity is unknown. We show that the expression of the ZC3H12A gene, which encodes MCPIP1, was induced by T1DM- and by T2DM-simulating conditions, with a stronger effect of cytokines. The number of MCPIP1-positive pancreatic islet-cells, including beta-cells, was significantly higher in diabetic compared to nondiabetic individuals. In the 3'UTR regions of mRNAs coding for Pdx1 (pancreatic and duodenal homeobox 1), FoxO1 (forkhead box protein O1), and of a novel regulator of insulin handling, Grp94 (glucose-regulated protein 94), MCPIP1-target structures were detected. Overexpression of the wild type MCPIP1_wt, but not of the mutant MCPIP1_D141N (lacking the RNase activity), decreased the expression of genes involved in insulin production and GSIS. Additionally INS1-E-MCPIP1_wt cells exhibited a higher Ire1 (inositol-requiring enzyme 1) expression. MCPIP1_wt overexpression blunted GSIS and glucose-mediated calcium influx with no deleterious effects on glucose uptake or glucokinase activity. We identify MCPIP1 as a new common link between diabetogenic conditions and beta-cell failure. MCPIP1 may serve as an interesting target for novel beta-cell protective approaches.

A Bittersweet Response to Infection in Diabetes; Targeting Neutrophils to Modify Inflammation and Improve Host Immunity

Chronic and recurrent infections occur commonly in both type 1 and type 2 diabetes (T1D, T2D) and increase patient morbidity and mortality. Neutrophils are professional phagocytes of the innate immune system that are critical in pathogen handling. Neutrophil responses to infection are dysregulated in diabetes, predominantly mediated by persistent hyperglycaemia; the chief biochemical abnormality in T1D and T2D. Therapeutically enhancing host immunity in diabetes to improve infection resolution is an expanding area of research. Individuals with diabetes are also at an increased risk of severe coronavirus disease 2019 (COVID-19), highlighting the need for re-invigorated and urgent focus on this field. The aim of this review is to explore the breadth of previous literature investigating neutrophil function in both T1D and T2D, in order to understand the complex neutrophil phenotype present in this disease and also to focus on the development of new therapies to improve aberrant neutrophil function in diabetes. Existing literature illustrates a dual neutrophil dysfunction in diabetes. Key pathogen handling mechanisms of neutrophil recruitment, chemotaxis, phagocytosis and intracellular reactive oxygen species (ROS) production are decreased in diabetes, weakening the immune response to infection. However, pro-inflammatory neutrophil pathways, mainly neutrophil extracellular trap (NET) formation, extracellular ROS generation and pro-inflammatory cytokine generation, are significantly upregulated, causing damage to the host and perpetuating inflammation. Reducing these proinflammatory outputs therapeutically is emerging as a credible strategy to improve infection resolution in diabetes, and also more recently COVID-19. Future research needs to drive forward the exploration of novel treatments to improve infection resolution in T1D and T2D to improve patient morbidity and mortality.

Molecular prospect of type-2 diabetes: Nanotechnology based diagnostics and therapeutic intervention

About ninety percent of all diabetic conditions account for T2D caused due to abnormal insulin secretion/ action or increased hepatic glucose production. Factors that contribute towards the aetiology of T2D could be well explained through biochemical, molecular, and cellular aspects. In this review, we attempt to explain the recent evolving molecular and cellular advancement associated with T2D pathophysiology. Current progress fabricated in T2D research concerning intracellular signaling cascade, inflammasome, autophagy, genetic and epigenetics changes is discretely explained in simple terms. Present available anti-diabetic therapeutic strategies commercialized and their limitations which are needed to be acknowledged are addressed in the current review. In particular, the pre-eminence of nanotechnology-based approaches to nullify the inadequacy of conventional anti-diabetic therapeutics and heterogeneous nanoparticulated systems exploited in diabetic researches are also discretely mentioned and are also listed in a tabular format in the review. Additionally, as a future prospect of nanotechnology, the review presents several strategic hypotheses to ameliorate the austerity of T2D by an engineered smart targeted nano-delivery system. In detail, an effort has been made to hypothesize novel nanotechnological based therapeutic strategies, which exploits previously described inflammasome, autophagic target points. Utilizing graphical description it is explained how a smart targeted nano-delivery system could promote β-cell growth and development by inducing the Wnt signaling pathway (inhibiting Gsk3β), inhibiting inflammasome (inhibiting NLRP3), and activating autophagic target points (protecting Atg3/Atg7 complex from oxidative stress) thereby might ameliorate the severity of T2D. Additionally, several targeting molecules associated with autophagic and epigenetic factors are also highlighted, which can be exploited in future diabetic research.

Repurposing metformin for covid-19 complications in patients with type 2 diabetes and insulin resistance

Understanding the exact role of current drugs in Covid-19 disease is essential in the era of global pandemics. Metformin which prescribed as the first-line treatment of type 2 diabetes has beneficial effects on Sars-cov2 infection. These effects are including regulation of immune system, Renin-Angiotensin System and Dipeptidyl Peptidase 4 function in Covid-19 infection. It also activates ACE2, the main receptor of Sars-cov2, in the epithelial cells of respiratory tissue through AMPK signaling and subsequently decreases the rate of viral adhesion. Metformin also declines the adherence of Sars-cov2 to DPP4 (the other receptor of the virus) on T cells. Hence, regulatory effects of metformin on membranous ACE2, and DPP4 can modulate immune reaction against Sars-cov2. Also, immunometabolic effects of metformin on inflammatory cells impair hyper-reactive immune response against the virus through reduction of glycolysis and propagation of mitochondrial oxidation. Metformin also decreases platelet aggravation and risk of thrombosis. In this article, we argue that metformin has beneficial effects on Covid-19 infection in patients with type 2 diabetes and insulin resistance. This opinion should be investigated in future clinical trials.

Ryanodine receptor and immune-related molecules in diabetic cardiomyopathy

Hyperglycaemia is a major aetiological factor in the development of diabetic cardiomyopathy. Excessive hyperglycaemia increases the levels of reactive carbonyl species (RCS), reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the heart and causes derangements in calcium homeostasis, inflammation and immune‐system disorders. Ryanodine receptor 2 (RyR2) plays a key role in excitation–contraction coupling during heart contractions, including rhythmic contraction and relaxation of the heart. Cardiac inflammation has been indicated in part though interleukin 1 (IL‐1) signals, supporting a role for B and T lymphocytes in diabetic cardiomyopathy. Some of the post‐translational modifications of the ryanodine receptor (RyR) by RCS, ROS and RNS stress are known to affect its gating and Ca²⁺ sensitivity, which contributes to RyR dysregulation in diabetic cardiomyopathy. RyRs and immune‐related molecules are important signalling species in many physiological and pathophysiological processes in various heart and cardiovascular diseases. However, little is known regarding the mechanistic relationship between RyRs and immune‐related molecules in diabetes, as well as the mechanisms mediating complex communication among cardiomyocytes, fibroblasts and immune cells. This review highlights new findings on the complex cellular communications in the pathogenesis and progression of diabetic cardiomyopathy. We discuss potential therapeutic applications targeting RyRs and immune‐related molecules in diabetic complications.

COVID-19 and metabolic comorbidities: An update on emerging evidences for optimal therapies

Type 2 diabetes mellitus, obesity, hypertension, and other associated metabolic complications have been demonstrated as a crucial contributor to the enhanced morbidity and mortality of patients with coronavirus disease 2019 (COVID-19). Data on the interplay between metabolic comorbidities and the outcomes in patients with COVID-19 have been emerging and rapidly increasing. This implies a mechanistic link between metabolic diseases and COVID-19 resulting in the exacerbation of the condition. Nonetheless, new evidences are emerging to support insulin-mediated aggressive glucose-lowering treatment as a possible trigger of high mortality rate in diabetic COVID-19 patients, putting the clinician in a confounding and difficult dilemma for the treatment of COVID-19 patients with metabolic comorbidities. Thus, this review discusses the pathophysiological link among severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), angiotensin-converting enzyme 2 (ACE2), metabolic complications, and severe inflammation in COVID-19 development, especially in those with multi-organ injuries. We discuss the influence of several routinely used drugs in COVID-19 patients, including anti-inflammatory and anti-coagulant drugs, antidiabetic drugs, renin-angiotensin-aldosterone system inhibitors. Especially, we provide a balanced overview on the clinical application of glucose-lowering drugs (insulin and metformin), angiotensin-converting-enzyme inhibitors, and angiotensin receptor blockers. Although there is insufficient evidence from clinical or basic research to comprehensively reveal the mechanistic link between adverse outcomes in COVID-19 and metabolic comorbidities, it is hoped that the update in the current review may help to better outline the optimal strategies for clinical management of COVID-19 patients with metabolic comorbidities.

Short-term fasting reshapes fat tissue

Intermittent fasting, which can effectively reduce obesity and improve the related metabolic syndrome has become an exciting research area in recent years. Adipose tissue is pivotal in regulating the metabolism and determining the occurrence of obesity. In the current study, we aimed to investigate the effects of acute fasting (AF) on fat tissue. Mice were subjected to AF for 36 h, receiving normal chow (low-fat diet [LFD]) or a high-fat diet (HFD), with free ad libitum access to drinking water, and those fed on free-diet counterparts without fasting serveding as controls. We found that AF obviously reshaped the morphology of fat tissue (WAT) and promoted the beiging of white adipose tissue in both LFD- and HFD-fed mice. AF principally improved the lipid metabolism, and increased the M2- polarization of macrophages in WAT white fat tissue of HFD-fed mice. Interestingly, we found that AF dramatically upregulated Sirt5 expression levels and fat tissue succinylation, suggesting that AF-induced beneficial effects on fat might occur via the regulation of Sirt5 levels and altered succinylation in fatty tissues. Our study clearly showed the remodeling function of adipose tissue during AF; in terms of mechanism, the regulation of succinylation levels by AF might provide new insights into the mechanism(s) underlying the improvement in fat metabolism by energy restriction.

Pulmonary and vascular effects of acute ozone exposure in diabetic rats fed an atherogenic diet

Air pollutants may increase risk for cardiopulmonary disease, particularly in susceptible populations with metabolic stressors such as diabetes and unhealthy diet. We investigated effects of inhaled ozone exposure and high-cholesterol diet (HCD) in healthy Wistar and Wistar-derived Goto-Kakizaki (GK) rats, a non-obese model of type 2 diabetes. Male rats (4-week old) were fed normal diet (ND) or HCD for 12 weeks and then exposed to filtered air or 1.0 ppm ozone (6 h/day) for 1 or 2 days. We examined pulmonary, vascular, hematology, and inflammatory responses after each exposure plus an 18-h recovery period. In both strains, ozone induced acute bronchiolar epithelial necrosis and inflammation on histopathology and pulmonary protein leakage and neutrophilia; the protein leakage was more rapid and persistent in GK compared to Wistar rats. Ozone also decreased lymphocytes after day 1 in both strains consuming ND (~50%), while HCD increased circulating leukocytes. Ozone increased plasma thrombin/antithrombin complexes and platelet disaggregation in Wistar rats on HCD and exacerbated diet effects on serum IFN-γ, IL-6, KC-GRO, IL-13, and TNF-α, which were higher with HCD (Wistar>GK). Ex vivo aortic contractility to phenylephrine was lower in GK versus Wistar rats at baseline(~30%); ozone enhanced this effect in Wistar rats on ND. GK rats on HCD had higher aortic e-NOS and tPA expression compared to Wistar rats. Ozone increased e-NOS in GK rats on ND (~3-fold) and Wistar rats on HCD (~2-fold). These findings demonstrate ways in which underlying diabetes and HCD may exacerbate pulmonary, systemic, and vascular effects of inhaled pollutants.

C-Peptide as a Therapy for Type 1 Diabetes Mellitus

Diabetes mellitus (DM) is a complex metabolic disease affecting one-third of the United States population. It is characterized by hyperglycemia, where the hormone insulin is either not produced sufficiently or where there is a resistance to insulin. Patients with Type 1 DM (T1DM), in which the insulin-producing beta cells are destroyed by autoimmune mechanisms, have a significantly increased risk of developing life-threatening cardiovascular complications, even when exogenous insulin is administered. In fact, due to various factors such as limited blood glucose measurements and timing of insulin administration, only 37% of T1DM adults achieve normoglycemia. Furthermore, T1DM patients do not produce C-peptide, a cleavage product from insulin processing. C-peptide has potential therapeutic effects in vitro and in vivo on many complications of T1DM, such as peripheral neuropathy, atherosclerosis, and inflammation. Thus, delivery of C-peptide in conjunction with insulin through a pump, pancreatic islet transplantation, or genetically engineered Sertoli cells (an immune privileged cell type) may ameliorate many of the cardiovascular and vascular complications afflicting T1DM patients.

Diabetes, obesity, metabolism, and SARS-CoV-2 infection: the end of the beginning

The increased prevalence of obesity, diabetes, and cardiovascular risk factors in people hospitalized with severe COVID-19 illness has engendered considerable interest in the metabolic aspects of SARS-CoV-2-induced pathophysiology. Here, I update concepts informing how metabolic disorders and their co-morbidities modify the susceptibility to, natural history, and potential treatment of SARS-CoV-2 infection, with a focus on human biology. New data informing genetic predisposition, epidemiology, immune responses, disease severity, and therapy of COVID-19 in people with obesity and diabetes are highlighted. The emerging relationships of metabolic disorders to viral-induced immune responses and viral persistence, and the putative importance of adipose and islet ACE2 expression, glycemic control, cholesterol metabolism, and glucose- and lipid-lowering drugs is reviewed, with attention to controversies and unresolved questions. Rapid progress in these areas informs our growing understanding of SARS-CoV-2 infection in people with diabetes and obesity, while refining the therapeutic strategies and research priorities in this vulnerable population.

Mesenchymal stromal cell-mediated immune regulation: A promising remedy in the therapy of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a major threat to global public health, with increasing prevalence as well as high morbidity and mortality, to which immune dysfunction has been recognized as a crucial contributor. Mesenchymal stromal cells (MSCs), obtained from various sources and possessing potent immunomodulatory abilities, have displayed great therapeutic potential for T2DM. Interestingly, the immunomodulatory capabilities of MSCs are endowed and plastic. Among the multiple mechanisms involved in MSC-mediated immune regulation, the paracrine effects of MSCs have attracted much attention. Of note, extracellular vesicles (EVs), an important component of MSC secretome, have emerged as pivotal mediators of their immunoregulatory effects. Particularly, the necrobiology of MSCs, especially apoptosis, has recently been revealed to affect their immunomodulatory functions in vivo. In specific, a variety of preclinical studies have demonstrated the beneficial effects of MSCs on improving islet function and ameliorating insulin resistance. More importantly, clinical trials have further uncovered the therapeutic potential of MSCs for T2DM. In this review, we outline current knowledge regarding the plasticity and underlying mechanisms of MSC-mediated immune modulation, focusing on the paracrine effects. We also summarize the applications of MSC-based therapies for T2DM in both preclinical studies and clinical trials, with particular emphasis on the modulation of immune system.

The relationship between rheumatoid arthritis and diabetes mellitus: a systematic review and meta-analysis

Supplemental Digital Content is available in the text.

Objective

This systematic review/meta-analysis was conducted to investigate the relationship between rheumatoid arthritis and the incidence of diabetes mellitus.

Methods

A comprehensive search was conducted up to 10 March 2020 in Medline (via Ovid), Embase (via Ovid) and Web of Science core collection to identify cohort studies comparing the risk of diabetes mellitus incidence in people with rheumatoid arthritis with the general population. The I2 statistic was used to test heterogeneity. Pooled relative risks were calculated using random-effects models. Publication bias was assessed using Egger’s test and Begg’s test.

Results

The initial search provided 3669 articles. Of those, five journal articles/two conference abstracts comprising 1 629 854 participants were included in this study. The funnel plot showed potential publication bias, proven by Egger’s test (−3.15, P < 0.01), but not Begg’s test (−0.05, P = 1.00). Heterogeneity was observed in I2 test (I2 = 96%, P < 0.01). We found that rheumatoid arthritis was associated with a higher risk of diabetes mellitus incidence (pooled relative risk, 1.23; 95% confidence interval, 1.07–1.40). Exploration of potential sources of heterogeneity found significant heterogeneity in different countries/regions (P = 0.002), but heterogeneity was NS in different study designs (P = 0.30). Sensitivity analyses confirmed that the association between rheumatoid arthritis and diabetes mellitus incidence was robust.

Conclusion

Rheumatoid arthritis is associated with an increased risk of diabetes mellitus incidence. This finding supports the notion that inflammatory pathways are involved in the pathogenesis of diabetes. More intensive interventions targeting diabetes risk factors should be considered in people with rheumatoid arthritis.

Autologous conditioned serum for degenerative diseases and prospects

Autologous conditioned serum (ACS) is a blood-derived product that is prepared by the incubation of whole blood with medical-grade glass beads, resulting in serum enrichment in interleukin-1 receptor antagonist (IL-1Ra), anti-inflammatory cytokines (IL-4, IL-10, and IL-13), and high concentrations of growth factors. ACS has shown qualitatively and quantitatively better therapeutic effects than most established pharmacological treatments and surgery for joint diseases given its ability to both target the inflammatory cascade to decrease cartilage destruction as well as improve endogenous repair mechanisms. ACS application is simple and safe with limited adverse effects. This article reviews the role of ACS in degenerative joint disease, in addition to other inflammatory and autoimmune diseases, given its regenerative and immune-modulating properties.