Pancreatic regulation of glucose homeostasis

Glucose-responsive microneedle patch for closed-loop dual-hormone delivery in mice and pigs

Insulin and glucagon secreted from the pancreas with dynamic balance play a vital role in regulating blood glucose levels. Although distinct glucose-responsive insulin delivery systems have been developed, the lack of a self-regulated glucagon release module limits their clinical applications due to the potential risk of hypoglycemia. Here, we describe a transdermal polymeric microneedle patch for glucose-responsive closed-loop insulin and glucagon delivery to achieve glycemic regulation with minimized risk of hypoglycemia. The glucose-responsive phenylboronic acid units can bind to glucose to reversibly shift the net charge (from positive to negative) of the entire polymeric matrix within microneedles. Therefore, the release ratio of the negatively charged insulin and the positively charged glucagon analog from the patch can be dynamically tuned upon the fluctuation of blood glucose levels to realize glycemic homeostasis. In both chemically induced type 1 diabetic mouse and minipig models, this glucose-responsive dual-hormone microneedle patch demonstrated tight long-term regulation in blood glucose levels (>24 hours in minipigs).

Sorafenib decreases glycemia by impairing hepatic glucose metabolism

PURPOSE

Sorafenib has been reported to reduce blood glucose levels in diabetic and non-diabetic patients in previous retrospective studies. However, the mechanism of which the hypoglycemic effects of sorafenib is not clearly explored. In this study, we investigated the effect of sorafenib on blood glucose levels in diabetic and normal mice and explored the possible mechanism.

METHODS

We established a mouse model of type 2 diabetes by a high-fat diet combined with a low-dose of streptozotocin (STZ), to identify the hypoglycemic effect of sorafenib in different mice. Glucose tolerance, insulin tolerance and pyruvate tolerance tests were done after daily gavage with sorafenib to diabetic and control mice. To explore the molecular mechanism by which sorafenib regulates blood glucose levels, hepatic glucose metabolism signaling was studied by a series of in vivo and in vitro experiments.

RESULTS

Sorafenib reduced blood glucose levels in both control and diabetic mice, particularly in the latter. The diabetic mice exhibited improved glucose and insulin tolerance after sorafenib treatment. Further studies showed that the expressions of gluconeogenesis-related enzymes, such as PCK1, G6PC and PCB, were significantly decreased upon sorafenib treatment. Mechanistically, sorafenib downregulates the expression of c-MYC downstream targets PCK1, G6PC and PCB through blocking the ERK/c-MYC signaling pathway, thereby playing its hypoglycemic effect by impairing hepatic glucose metabolism.

CONCLUSION

Sorafenib reduces blood glucose levels through downregulating gluconeogenic genes, especially in diabetic mice, suggesting the patients with T2DM when treated with sorafenib need more emphasis in monitoring blood glucose to avoid unnecessary hypoglycemia.

Global research trends on the links between insulin resistance and obesity: a visualization analysis

Background

Obesity increases the chance of developing insulin resistance. Numerous inflammatory markers have been linked to an increased risk of insulin resistance in obese individuals. Therefore, we performed a bibliometric analysis to determine global research activity and current trends in the field of obesity and insulin resistance.

Methods

Scopus was used between 2002 and 2021 to retrieve publications related to terms related to obesity and insulin resistance. Data were exported to Microsoft Excel. Additionally, we use VOSviewer software to create visualization maps that describe international collaborations and research hotspots.

Results

We identified 6626 publications, including 5754 journal articles, 498 review articles, and 109 letters to the editor. The most productive countries were the United States (n = 995, 30.11%), followed by China (n = 650, 9.81%), Italy (n = 412, 6.22%) and Spain (n = 386, 5.83%). Previously to 2012, this field was mainly focused on ‘adipocyte dysfunctions that link obesity with insulin resistance”; and ‘relationship between obesity, insulin resistance, and risk of cardiovascular disease’. ‘Supplements improve insulin sensitivity‘, and ‘obesity-induced inflammation and insulin resistance’ were found more recently (after 2014), indicating that research in this field has acquired significant interest and emphasis in recent years.

Conclusions

This is the first bibliometric study to focus on publications related to insulin resistance and obesity at the global level. Our reporting of quantifiable knowledge in this field may be useful in providing evidence and direction for future research, clinical practice, and educational initiatives.

An integrative exploration of loquat leaf total sesquiterpene glycosides in treating insulin-resistant mice by serum and urine untargeted metabolomics analysis

Loquat leaf is approved to be beneficial in the treatment of diabetes. Total sesquiterpene glycosides (TSG), a major chemical component cluster, has potential ability to improve insulin-resistant diabetes syndrome. Its therapeutic mechanism using metabolomics in vivo is worth to be investigated. This study aimed to reveal the underlying therapeutic mechanism of TSG on insulin-resistant mice by untargeted metabolomics, and to explore the lipid metabolism differences in vivo. High-fat diet was used to induce insulin-resistant mice model. Biochemical indicators were applied to evaluate the model validity and related treatment effect. Ultra-performance liquid chromatography quadrupole-time-of-flight mass spectrometry was utilized to accomplish serum and urine untargeted metabolomics. Oral administration of TSG had a therapeutic effect on high-fat diet induced insulin-resistant mice. Four hundred forty-two metabolites in serum and 1732 metabolites in urine were annotated. Principal component analysis screened 324 differential metabolic signatures in serum sample and 1408 in urine sample. The pathway mainly involved purine metabolism and biosynthesis of unsaturated fatty acids. Lipidomic analysis of urine and serum confirmed that most lipid metabolites were fatty acyls, sterol lipids and polyketides.

Impact of Diabetes Mellitus in Patients with Pancreatic Neuro-Endocrine Tumors: Causes, Consequences, and Future Perspectives

Diabetes mellitus (DM) and pancreatic neuroendocrine tumors (pNETs) are two entities closely linked together. DM has been described as a risk factor for the development of pNETs and for the aggressiveness of the disease. On the other hand, DM due to pNETs is frequently undiagnosed or misclassified as type 2 DM when it is due to type 3 DM. In addition, metformin, a commonly prescribed drug for type 2 DM, has an antiproliferative property and is gaining increasing attention as an antitumor agent. This review article presents the findings published in the last few years on pNETs and DMs. Emphasis will be placed on DM as a risk factor, pNET as a risk factor for the development of type 3 DM, the management of type 3 DM on pNET, and DM as a prognostic factor in patients with pNET, as well as the future clinical implications of DM in these patients. The coexistence of DM and pNET is extensively presented. It is important to perform future clinical trials, which are necessary to establish the role of metformin on pNET disease. Increasing awareness among professionals managing pNET on the importance of a correct DM diagnosis and management of the disease must be a priority due to the implications on mortality and comorbidities it may have in these patients.

Mapping and targeted viral activation of pancreatic nerves in mice reveal their roles in the regulation of glucose metabolism

A lack of comprehensive mapping of ganglionic inputs into the pancreas and of technology for the modulation of the activity of specific pancreatic nerves has hindered the study of how they regulate metabolic processes. Here we show that the pancreas-innervating neurons in sympathetic, parasympathetic and sensory ganglia can be mapped in detail by using tissue clearing and retrograde tracing (the tracing of neural connections from the synapse to the cell body), and that genetic payloads can be delivered via intrapancreatic injection to target sites in efferent pancreatic nerves in live mice through optimized adeno-associated viruses and neural-tissue-specific promoters. We also show that, in male mice, the targeted activation of parasympathetic cholinergic intrapancreatic ganglia and neurons doubled plasma-insulin levels and improved glucose tolerance, and that tolerance was impaired by stimulating pancreas-projecting sympathetic neurons. The ability to map the peripheral ganglia innervating the pancreas and to deliver transgenes to specific pancreas-projecting neurons will facilitate the examination of ganglionic inputs and the study of the roles of pancreatic efferent innervation in glucose metabolism.

Personalized reference intervals: from theory to practice

Using laboratory test results for diagnosis and monitoring requires a reliable reference to which the results can be compared. Currently, most reference data is derived from the population, and patients in this context are considered members of a population group rather than individuals. However, such reference data has limitations when used as the reference for an individual. A patient's test results preferably should be compared with their own, individualized reference intervals (RI), i.e. a personalized RI (prRI).The prRI is based on the homeostatic model and can be calculated using an individual's previous test results obtained in a steady-state situation and estimates of analytical (CV_A) and biological variation (BV). BV used to calculate the prRI can be obtained from the population (within-subject biological variation, CV_I) or an individual's own data (within-person biological variation, CV_P). Statistically, the prediction interval provides a useful tool to calculate the interval (i.e. prRI) for future observation based on previous measurements. With the development of information technology, the data of millions of patients is stored and processed in medical laboratories, allowing the implementation of personalized laboratory medicine. PrRI for each individual should be made available as part of the laboratory information system and should be continually updated as new test results become available.In this review, we summarize the limitations of population-based RI for the diagnosis and monitoring of disease, provide an outline of the prRI concept and different approaches to its determination, including statistical considerations for deriving prRI, and discuss aspects which must be further investigated prior to implementation of prRI in clinical practice.

Altered microvasculature in pancreatic islets from subjects with type 1 diabetes

AIMS

The transcriptome of different dissociated pancreatic islet cells has been described in enzymatically isolated islets in both health and disease. However, the isolation, culturing, and dissociation procedures likely affect the transcriptome profiles, distorting the biological conclusions. The aim of the current study was to characterize the cells of the islets of Langerhans from subjects with and without type 1 diabetes in a way that reflects the in vivo situation to the highest possible extent.

METHODS

Islets were excised using laser capture microdissection directly from frozen pancreatic tissue sections obtained from organ donors with (n = 7) and without (n = 8) type 1 diabetes. Transcriptome analysis of excised samples was performed using AmpliSeq. Consecutive pancreatic sections were used to estimate the proportion of beta-, alpha-, and delta cells using immunofluorescence and to examine the presence of CD31 positive endothelial regions using immunohistochemistry.

RESULTS

The proportion of beta cells in islets from subjects with type 1 diabetes was reduced to 0% according to both the histological and transcriptome data, and several alterations in the transcriptome were derived from the loss of beta cells. In total, 473 differentially expressed genes were found in the islets from subjects with type 1 diabetes. Functional enrichment analysis showed that several of the most upregulated gene sets were related to vasculature and angiogenesis, and histologically, vascular density was increased in subjects with type 1 diabetes. Downregulated in type 1 diabetes islets was the gene set epithelial mesenchymal transition.

CONCLUSION

A number of transcriptional alterations are present in islets from subjects with type 1 diabetes. In particular, several gene sets related to vasculature and angiogenesis are upregulated and there is an increased vascular density, suggesting an altered microvasculature in islets from subjects with type 1 diabetes. By studying pancreatic islets extracted directly from snap-frozen pancreatic tissue, this study reflects the in vivo situation to a high degree and gives important insights into islet pathophysiology in type 1 diabetes.

Gi/o protein-coupled receptor inhibition of beta-cell electrical excitability and insulin secretion depends on Na+/K+ ATPase activation

Gi/o-coupled somatostatin or α2-adrenergic receptor activation stimulated β-cell NKA activity, resulting in islet Ca2+ fluctuations. Furthermore, intra-islet paracrine activation of β-cell Gi/o-GPCRs and NKAs by δ-cell somatostatin secretion slowed Ca2+ oscillations, which decreased insulin secretion. β-cell membrane potential hyperpolarization resulting from Gi/o-GPCR activation was dependent on NKA phosphorylation by Src tyrosine kinases. Whereas, β-cell NKA function was inhibited by cAMP-dependent PKA activity. These data reveal that NKA-mediated β-cell membrane potential hyperpolarization is the primary and conserved mechanism for Gi/o-GPCR control of electrical excitability, Ca2+ handling, and insulin secretion.

Elevations in blood glucose before and after the appearance of islet autoantibodies in children

The etiology of type 1 diabetes has polygenic and environmental determinants that lead to autoimmune responses against pancreatic β cells and promote β cell death. The autoimmunity is considered silent without metabolic consequences until late preclinical stages,and it remains unknown how early in the disease process the pancreatic β cell is compromised. To address this, we investigated preprandial nonfasting and postprandial blood glucose concentrations and islet autoantibody development in 1,050 children with high genetic risk of type 1 diabetes. Pre- and postprandial blood glucose decreased between 4 and 18 months of age and gradually increased until the final measurements at 3.6 years of age. Determinants of blood glucose trajectories in the first year of life included sex, body mass index, glucose-related genetic risk scores, and the type 1 diabetes-susceptible INS gene. Children who developed islet autoantibodies had early elevations in blood glucose concentrations. A sharp and sustained rise in postprandial blood glucose was observed at around 2 months prior to autoantibody seroconversion, with further increases in postprandial and, subsequently, preprandial values after seroconversion. These findings show heterogeneity in blood glucose control in infancy and early childhood and suggest that islet autoimmunity is concurrent or subsequent to insults on the pancreatic islets.

Therapeutic Potential of miRNAs for Type 2 Diabetes Mellitus: An Overview

MicroRNA(miRNA)s have been identified as an emerging class for therapeutic interventions mainly due to their extracellularly stable presence in humans and animals and their potential for horizontal transmission and action. However, treating Type 2 diabetes mellitus using this technology has yet been in a nascent state. MiRNAs play a significant role in the pathogenesis of Type 2 diabetes mellitus establishing the potential for utilizing miRNA-based therapeutic interventions to treat the disease. Recently, the administration of miRNA mimics or antimiRs in-vivo has resulted in positive modulation of glucose and lipid metabolism. Further, several cell culture-based interventions have suggested beta cell regeneration potential in miRNAs. Nevertheless, few such miRNA-based therapeutic approaches have reached the clinical phase. Therefore, future research contributions would identify the possibility of miRNA therapeutics for tackling T2DM. This article briefly reported recent developments on miRNA-based therapeutics for treating Type 2 Diabetes mellitus, associated implications, gaps, and recommendations for future studies.

The relationship between poor glycaemic control at different time points of gestational diabetes mellitus and pregnancy outcomes

We aimed to identify the complications of gestational diabetes mellitus (GDM) associated with poor control of fasting plasma glucose (FPG) and postload plasma glucose (PPG) on the 75-g oral glucose tolerance test (OGTT). This retrospective study included 997 singleton pregnancy GDM patients who were assigned to poor or good glycaemic control groups. Multivariate analysis indicated that poor FPG control and poor PPG control were both independent predictors of hypertensive disorder complicating pregnancy (HDCP) (odd ratio (OR) of 2.551 (95% CI [1.146-5.682], p = .022) and OR of 2.084 (95% [1.115-3.894], p = .021) compared with good glycaemic control groups, respectively). Poor PPG control promoted the rate of caesarean delivery (1.534 (95% CI [1.063-2.214]), p = .022), whereas good PPG control increased the risk of premature rupture of membranes (PROM) (0.373 (95% CI [0.228-0.611]), p < .001). Conclusively, poor control FPG and PPG dissimilarly affect pregnancy complications in GDM; these findings may help clinicians in the effective implementation of measures to prevent pregnancy complications in GDM.IMPACT STATEMENTWhat is already known on this subject? Previous studies displayed that GDM patients with 2-h PPG elevated at 24-28 week of gestation had a 2.254-fold increased risk of postpartum dysglycaemia. Abnormal plasma glucose in GDM mother increased the probability of childhood obesity in the offspring. With the implementation of China's second-child policy, the incidence of GDM is rising.What do the results of this study add? Our results indicated that the older patients with GDM, the greater the risk of abnormal plasma glucose control. In addition, maternal age and prenatal BMI were notably correlated with poor plasma glucose control of FPG and PPG, respectively. We also found that both poor FPG and PPG control notably increased the incidence of HDCP in pregnant women. The incidence of PROM was higher in the good PPG control group compared with the poor PPG control group.What are the implications of these findings for clinical practice and/or further research? This study displayed that the effects of poor FPG and PPG control on pregnancy complications and newborn outcomes were heterogeneous, which might be related to the specificity of plasma glucose metabolism at different time points. Good glycaemic control, especially PPG control, was of great significance for improving pregnancy complications and perinatal conditions.

Current and future approaches for in vitro hit discovery in diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a serious public health problem. In this review, we discuss current and promising future drugs, targets, in vitro assays and emerging omics technologies in T2DM. Importantly, we open the perspective to image-based high-content screening (HCS), with the focus of combining it with metabolomics or lipidomics. HCS has become a strong technology in phenotypic screens because it allows comprehensive screening for the cell-modulatory activity of small molecules. Metabolomics and lipidomics screen for perturbations at the molecular level. The combination of these data-intensive comprehensive technologies is enabled by the rapid development of artificial intelligence. It promises a deep cellular and molecular phenotyping directly linked to chemical information about the applied drug candidates or complex mixtures.

The role of GABA in islet function

Gamma aminobutyric acid (GABA) is a non-proteinogenic amino acid and neurotransmitter that is produced in the islet at levels as high as in the brain. GABA is synthesized by the enzyme glutamic acid decarboxylase (GAD), of which the 65 kDa isoform (GAD65) is a major autoantigen in type 1 diabetes. Originally described to be released via synaptic-like microvesicles or from insulin secretory vesicles, beta cells are now understood to release substantial quantities of GABA directly from the cytosol via volume-regulated anion channels (VRAC). Once released, GABA influences the activity of multiple islet cell types through ionotropic GABAA receptors and metabotropic GABAB receptors. GABA also interfaces with cellular metabolism and ATP production via the GABA shunt pathway. Beta cells become depleted of GABA in type 1 diabetes (in remaining beta cells) and type 2 diabetes, suggesting that loss or reduction of islet GABA correlates with diabetes pathogenesis and may contribute to dysfunction of alpha, beta, and delta cells in diabetic individuals. While the function of GABA in the nervous system is well-understood, the description of the islet GABA system is clouded by differing reports describing multiple secretion pathways and effector functions. This review will discuss and attempt to unify the major experimental results from over 40 years of literature characterizing the role of GABA in the islet.

Hepatic Sam68 Regulates Systemic Glucose Homeostasis and Insulin Sensitivity

Hepatic glucose production (HGP) is an important component of glucose homeostasis, and deregulated HGP, particularly through gluconeogenesis, contributes to hyperglycemia and pathology of type-2 diabetes (T2D). It has been shown that the gluconeogenic gene expression is governed primarily by the transcription factor cAMP-response element (CRE)-binding protein (CREB) and its coactivator, CREB-regulated transcriptional coactivator 2 (CRTC2). Recently, we have discovered that Sam68, an adaptor protein and Src kinase substrate, potently promotes hepatic gluconeogenesis by promoting CRTC2 stability; however, the detailed mechanisms remain unclear. Here we show that in response to glucagon, Sam68 increases CREB/CRTC2 transactivity by interacting with CRTC2 in the CREB/CRTC2 complex and occupying the CRE motif of promoters, leading to gluconeogenic gene expression and glucose production. In hepatocytes, glucagon promotes Sam68 nuclear import, whereas insulin elicits its nuclear export. Furthermore, ablation of Sam68 in hepatocytes protects mice from high-fat diet (HFD)-induced hyperglycemia and significantly increased hepatic and peripheral insulin sensitivities. Thus, hepatic Sam68 potentiates CREB/CRTC2-mediated glucose production, contributes to the pathogenesis of insulin resistance, and may serve as a therapeutic target for T2D.

The Pancreas and Known Factors of Acute Pancreatitis

Pancreatitis is regarded by clinicians as one of the most complicated and clinically challenging of all disorders affecting the abdomen. It is classified on the basis of clinical, morphological, and histological criteria. Causes of acute pancreatitis can easily be identified in 75–85% of patients. The main causes of acute, recurrent acute, and chronic pancreatitis are gallstone migration and alcohol abuse. Other causes are uncommon, controversial, or unexplained. For instance, cofactors of all forms of pancreatitis are pancreas divisum and hypertriglyceridemia. Another factor that should be considered is a complication of endoscopic retrograde cholangiopancreatography: post-endoscopic retrograde cholangiopancreatography acute pancreatitis. The aim of this study is to present the known risk factors for acute pancreatitis, beginning with an account of the morphology, physiology, and development of the pancreas.

Layered feedback control overcomes performance trade-off in synthetic biomolecular networks

Layered feedback is an optimization strategy in feedback control designs widely used in engineering. Control theory suggests that layering multiple feedbacks could overcome the robustness-speed performance trade-off limit. In natural biological networks, genes are often regulated in layers to adapt to environmental perturbations. It is hypothesized layering architecture could also overcome the robustness-speed performance trade-off in genetic networks. In this work, we validate this hypothesis with a synthetic biomolecular network in living E. coli cells. We start with system dynamics analysis using models of various complexities to guide the design of a layered control architecture in living cells. Experimentally, we interrogate system dynamics under three groups of perturbations. We consistently observe that the layered control improves system performance in the robustness-speed domain. This work confirms that layered control could be adopted in synthetic biomolecular networks for performance optimization. It also provides insights into understanding genetic feedback control architectures in nature.

A Hot Water Extract of Curcuma longa L. Improves Fasting Serum Glucose Levels in Participants with Low-Grade Inflammation: Reanalysis of Data from Two Randomized, Double-Blind, Placebo-Controlled Trials

The dietary spice Curcuma longa L. (C. longa), also known as turmeric, has various biological effects. A hot water extract of C. longa was shown to have anti-inflammatory activities in preclinical and clinical studies. Chronic low-grade inflammation is associated with the disruption of glucose homeostasis, but the effect of C. longa extract on glucose metabolism in humans is poorly understood. Therefore, we investigated the effect of C. longa extracts on serum glucose levels in the presence of low-grade inflammation. We reanalyzed our published data from two randomized, double-blind, placebo-controlled trials in overweight participants aged 50 to 69 years and performed a stratified analysis using the inflammatory marker high-sensitivity C-reactive protein (hsCRP). In both studies, participants took a test food with a hot water extract of C. longa (C. longa extract group, n = 45 per study) or without C. longa extract (placebo group, n = 45 per study) daily for 12 weeks, and we measured the levels of serum hsCRP and fasting serum glucose. The mean baseline hsCRP value was used to stratify participants into two subgroups: a low-hsCRP subgroup (baseline mean hsCRP < 0.098 mg/dL) and a high-hsCRP subgroup (baseline mean hsCRP ≥ 0.098 mg/dL). In the low-hsCRP subgroup, we found no significant difference in fasting serum glucose levels between the two groups in either study, but in the high-hsCRP subgroup, the C. longa extract group had significantly lower levels of serum hsCRP (p < 0.05) and fasting serum glucose (p < 0.05) than the placebo group in both studies. In conclusion, a hot water extract of C. longa may help to improve systemic glucose metabolism in people with chronic low-grade inflammation.

Cholic acid inhibits amyloid fibrillation: Interplay of protonation and deprotonation

Amyloidopathies are the consequence of misfolding with subsequent aggregation affecting people worldwide. Irrespective of speedy advancement in the field of therapeutics no agent for treating amyloidopathies has been discovered and thus targeting amyloid fibrillation process via repositioning of small molecules can be fruitful. According to previous reports potential amyloid inhibitors possess unique features like, hydrophobicity, aromaticity, charge etc. Herein, we have explored the effect of Cholic acid (CA) on amyloid fibrillation irrespective of the charge (determined by Zetasizer) using four proteins Human Serum Albumin, Bovine Serum Albumin, Human Insulin and Beta-lactoglobulin (HSA, BSA, HI and BLG) employing biophysical, imaging and computational techniques. ThT results revealed that CA in both protonated and deprotonated form is potent to curb HSA, BSA, BLG aggregation ~50% and HI aggregation ~96% in a dose dependent manner (in accord with CD, ANS and Congo red assay). Interestingly, CA treated samples displayed reduced cytotoxicity (Hemolytic assay) with altered morphology (TEM) and mechanism behind inhibition may be the interaction of CA with proteins via hydrophobic interactions and hydrogen bonding (supported by molecular docking results). This study proved CA (irrespective of the pH) a potential inhibitor of amyloidosis thus can be helpful in generalizing and repurposing the related drugs/compounds for their anti-aggregation behavior as an implication towards treating amyloidopathies.

A glucose-insulin-glucagon coupled model of the isoglycemic intravenous glucose infusion experiment

Type 2 diabetes (T2D) is a pathophysiology that is characterized by insulin resistance, beta- and alpha-cell dysfunction. Mathematical models of various glucose challenge experiments have been developed to quantify the contribution of insulin and beta-cell dysfunction to the pathophysiology of T2D. There is a need for effective extended models that also capture the impact of alpha-cell dysregulation on T2D. In this paper a delay differential equation-based model is developed to describe the coupled glucose-insulin-glucagon dynamics in the isoglycemic intravenous glucose infusion (IIGI) experiment. As the glucose profile in IIGI is tailored to match that of a corresponding oral glucose tolerance test (OGTT), it provides a perfect method for studying hormone responses that are in the normal physiological domain and without the confounding effect of incretins and other gut mediated factors. The model was fit to IIGI data from individuals with and without T2D. Parameters related to glucagon action, suppression, and secretion as well as measures of insulin sensitivity, and glucose stimulated response were determined simultaneously. Significant impairment in glucose dependent glucagon suppression was observed in patients with T2D (duration of T2D: 8 (6-36) months) relative to weight matched control subjects (CS) without diabetes (k1 (mM)-1: 0.16 ± 0.015 (T2D, n = 7); 0.26 ± 0.047 (CS, n = 7)). Insulin action was significantly lower in patients with T2D (a1 (10 pM min)-1: 0.000084 ± 0.0000075 (T2D); 0.00052 ± 0.00015 (CS)) and the Hill coefficient in the equation for glucose dependent insulin response was found to be significantly different in T2D patients relative to CS (h: 1.4 ± 0.15; 1.9 ± 0.14). Trends in parameters with respect to fasting plasma glucose, HbA1c and 2-h glucose values are also presented. Significantly, a negative linear relationship is observed between the glucagon suppression parameter, k1, and the three markers for diabetes and is thus indicative of the role of glucagon in exacerbating the pathophysiology of diabetes (Spearman Rank Correlation: (n = 12; (-0.79, 0.002), (-0.73,.007), (-0.86,.0003)) respectively).

Integrated Analysis of Transcriptome and Metabolome Reveals Distinct Responses of Pelteobagrus fulvidraco against Aeromonas veronii Infection at Invaded and Recovering Stage

Yellow catfish (Pelteobagrus fulvidraco) is an important aquaculture fish susceptible to Aeromonas veronii infection, which causes acute death resulting in huge economic losses. Understanding the molecular processes of host immune defense is indispensable to disease control. Here, we conducted the integrated and comparative analyses of the transcriptome and metabolome of yellow catfish in response to A. veronii infection at the invaded stage and recovering stage. The crosstalk between A. veronii-induced genes and metabolites uncovered the key biomarkers and pathways that strongest contribute to different response strategies used by yellow catfish at corresponding defense stages. We found that at the A. veronii invading stage, the immune defense was strengthened by synthesizing lipids with energy consumption to repair the skin defense line and accumulate lipid droplets promoting intracellular defense line; triggering an inflammatory response by elevating cytokine IL-6, IL-10 and IL-1β following PAMP-elicited mitochondrial signaling, which was enhanced by ROS produced by impaired mitochondria; and activating apoptosis by up-regulating caspase 3, 7 and 8 and Prostaglandin F1α, meanwhile down-regulating FoxO3 and BCL6. Apoptosis was further potentiated via oxidative stress caused by mitochondrial dysfunction and exceeding inflammatory response. Additionally, cell cycle arrest was observed. At the fish recovering stage, survival strategies including sugar catabolism with D-mannose decreasing; energy generation through the TCA cycle and Oxidative phosphorylation pathways; antioxidant protection by enhancing Glutathione (oxidized), Anserine, and α-ketoglutarate; cell proliferation by inducing Cyclin G2 and CDKN1B; and autophagy initiated by FoxO3, ATG8 and ATP6V1A were highlighted. This study provides a comprehensive picture of yellow catfish coping with A. veronii infection, which adds new insights for deciphering molecular mechanisms underlying fish immunity and developing stage-specific disease control techniques in aquaculture.

VAMP4 regulates insulin levels by targeting secretory granules to lysosomes

Insulin levels are essential for the maintenance of glucose homeostasis, and deviations lead to pathoglycemia or diabetes. However, the metabolic mechanism controlling insulin quantity and quality is poorly understood. In pancreatic β cells, insulin homeostasis and release are tightly governed by insulin secretory granule (ISG) trafficking, but the required regulators and mechanisms are largely unknown. Here, we identified that VAMP4 controlled the insulin levels in response to glucose challenge. VAMP4 deficiency led to increased blood insulin levels and hyperresponsiveness to glucose. In β cells, VAMP4 is packaged into immature ISGs (iISGs) at trans-Golgi networks and subsequently resorted to clathrin-coated vesicles during granule maturation. VAMP4-positive iISGs and resorted vesicles then fuse with lysosomes facilitated by a SNARE complex consisting of VAMP4, STX7, STX8, and VTI1B, which ensures the breakdown of excess (pro)insulin and obsolete materials and thus maintenance of intracellular insulin homeostasis. Thus, VAMP4 is a key factor regulating the insulin levels and a potential target for the treatment of diabetes.

Cross Talk Between Insulin and Glucagon Receptor Signaling in the Hepatocyte

While the consumption of external energy (i.e., feeding) is essential to life, this action induces a temporary disturbance of homeostasis in an animal. A primary example of this effect is found in the regulation of glycemia. In the fasted state, stored energy is released to maintain physiological glycemic levels. Liver glycogen is liberated to glucose, glycerol and (glucogenic) amino acids are used to build new glucose molecules (i.e., gluconeogenesis), and fatty acids are oxidized to fuel long-term energetic demands. This regulation is driven primarily by the counterregulatory hormones epinephrine, growth hormone, cortisol, and glucagon. Conversely, feeding induces a rapid influx of diverse nutrients, including glucose, that disrupt homeostasis. Consistently, a host of hormonal and neural systems under the coordination of insulin are engaged in the transition from fasting to prandial states to reduce this disruption. The ultimate action of these systems is to appropriately store the newly acquired energy and to return to the homeostatic norm. Thus, at first glance it is tempting to assume that glucagon is solely antagonistic regarding the anabolic effects of insulin. We have been intrigued by the role of glucagon in the prandial transition and have attempted to delineate its role as beneficial or inhibitory to glycemic control. The following review highlights this long-known yet poorly understood hormone.

Variant-to-gene-mapping analyses reveal a role for pancreatic islet cells in conferring genetic susceptibility to sleep-related traits

We investigated the potential role of sleep-trait associated genetic loci in conferring a degree of their effect via pancreatic α- and β-cells, given that both sleep disturbances and metabolic disorders, including type 2 diabetes and obesity, involve polygenic contributions and complex interactions. We determined genetic commonalities between sleep and metabolic disorders, conducting linkage disequilibrium genetic correlation analyses with publicly available GWAS summary statistics. Then we investigated possible enrichment of sleep-trait associated SNPs in promoter-interacting open chromatin regions within α- and β-cells, intersecting public GWAS reports with our own ATAC-seq and high-resolution promoter-focused Capture C data generated from both sorted human α-cells and an established human beta-cell line (EndoC-βH1). Finally, we identified putative effector genes physically interacting with sleep-trait associated variants in α- and EndoC-βH1cells running variant-to-gene mapping and establish pathways in which these genes are significantly involved. We observed that insomnia, short and long sleep-but not morningness-were significantly correlated with type 2 diabetes, obesity and other metabolic traits. Both the EndoC-βH1 and α-cells were enriched for insomnia loci (p = .01; p = .0076), short sleep loci (p = .017; p = .022) and morningness loci (p = 2.2 × 10-7; p = .0016), while the α-cells were also enriched for long sleep loci (p = .034). Utilizing our promoter contact data, we identified 63 putative effector genes in EndoC-βH1 and 76 putative effector genes in α-cells, with these genes showing significant enrichment for organonitrogen and organophosphate biosynthesis, phosphatidylinositol and phosphorylation, intracellular transport and signaling, stress responses and cell differentiation. Our data suggest that a subset of sleep-related loci confer their effects via cells in pancreatic islets.

Adiposity Metabolic Consequences for Adolescent Bone Health

Infancy and adolescence are crucial periods for bone health, since they are characterized by intense physical growth and bone development. The unsatisfactory acquisition of bone mass in this phase has consequences in adult life and increases the risk of developing bone diseases at more advanced ages. Nutrient deficiencies, especially calcium and vitamin D, associated with a sedentary lifestyle; lack of sun exposure; and epigenetic aspects represent some of the main risk factors for poor bone quality. In addition, recent studies relate childhood obesity to impaired bone health; however, studies on the adiposity effects on bone health are scarce and inconclusive. Another gap concerns the implications of obesity on child sexual maturity, which can jeopardize their genetic potential bone mass and increase fracture risk. Therefore, we reviewed the analyzed factors related to bone health and their association with obesity and metabolic syndrome in adolescents. We concluded that obesity (specifically, accumulated visceral fat) harms bones in the infant-juvenile phase, thereby increasing osteopenia/osteoporosis in adults and the elderly. Thus, it becomes evident that forming and maintaining healthy eating habits is necessary during infancy and adolescence to reduce the risk of fractures caused by bone-metabolic diseases in adulthood and to promote healthy ageing.

Characterisation of an Atrx Conditional Knockout Mouse Model: Atrx Loss Causes Endocrine Dysfunction Rather Than Pancreatic Neuroendocrine Tumour

Simple Summary

ATRX and DAXX mutations occur in 30–40% of pancreatic neuroendocrine tumours (PanNETs), and there are no reports in the literature of any genetically engineered mouse model (GEMM) evaluating the effect of Atrx disruption as a putative driver event on PanNET initiation. We created a novel GEMM with Atrx conditional disruption in β cells. We observed that this genetic alteration, per se, was not tumourigenic, but we reported novel roles of Atrx on endocrine function, which resulted in dysglycaemia and the exacerbation of inflammageing (increased pancreatic inflammation and hepatic steatosis).

Abstract

ATRX is a chromatin remodeller that maintains telomere homeostasis. Loss of ATRX is described in approximately 10% of pancreatic neuroendocrine tumours (PanNETs) and associated with poorer prognostic features. Here, we present a genetically engineered mouse model (GEMM) addressing the role of Atrx loss (Atrx^KO) in pancreatic β cells, evaluating a large cohort of ageing mice (for up to 24 months (mo.)). Atrx loss did not cause PanNET formation but rather resulted in worsening of ageing-related pancreatic inflammation and endocrine dysfunction in the first year of life. Histopathological evaluation highlighted an exacerbated prevalence and intensity of pancreatic inflammation, ageing features, and hepatic steatosis in Atrx^KO mice. Homozygous floxed mice presented hyperglycaemia, increased weights, and glucose intolerance after 6 months, but alterations in insulinaemia were not detected. Floxed individuals presented an improper growth of their pancreatic endocrine fraction that may explain such an endocrine imbalance. A pilot study of BRACO-19 administration to Atrx^KO mice resulted in telomere instability, reinforcing the involvement of Atrx in the maintenance of β cell telomere homeostasis. Thereby, a non-obese dysglycaemic GEMM of disrupted Atrx is here presented as potentially useful for metabolic studies and putative candidate for inserting additional tumourigenic genetic events.

MD Simulation Studies for Selective Phytochemicals as Potential Inhibitors against Major Biological Targets of Diabetic Nephropathy

Diabetes is emerging as an epidemic and is becoming a public health concern worldwide. Diabetic nephropathy is one of the serious complications of diabetes, and about 40% of individuals with diabetes develop diabetic nephropathy. The consistent feature of diabetes and its associated nephropathy is hyperglycemia, and in some cases, hyperamylinemia. Currently, the treatment includes the use of medication for blood pressure control, sugar control, and cholesterol control, and in the later stage requires dialysis and kidney transplantation, making the management of this complication very difficult. Bioactive compounds, herbal medicines, and extracts are extensively used in the treatment and prevention of several diseases, and some are reported to be efficacious in diabetes too. Therefore, in this study, we tried to identify the therapeutic potential of phytochemicals used in in silico docking and molecular dynamic simulation studies using a library of 5284 phytochemicals against the two potential targets of type 2 diabetes-associated nephropathy. We identified two phytochemicals (i.e., gentisic acid and michelalbine) that target human amylin peptide and dipeptidyl peptidase-4, respectively, with good binding affinity. These phytochemicals can be further evaluated using in vitro and in vivo studies for their anti-hyperglycemia and anti-hyperamylinemia effects.

Evaluation of Antidiabetic Activity of Biogenic Silver Nanoparticles Using Thymus serpyllum on Streptozotocin-Induced Diabetic BALB/c Mice

Type 2 Diabetes Mellitus is one of the most common metabolic disorders, and is characterized by abnormal blood sugar level due to impaired insulin secretion or impaired insulin action—or both. Metformin is the most commonly used drug for the treatment of Type 2 Diabetes Mellitus, but due to its slow mode of action and various side effects it shows poor and slow therapeutic response in patients. Currently, scientists are trying to tackle these limitations by developing nanomedicine. This research reports novel synthesis of silver nanoparticles using aqueous extract of Thymus serpyllum and aims to elucidate its therapeutic potential as an antidiabetic agent on streptozotocin induced diabetic BALB/c mice. Thymus serpyllum mediated silver nanoparticles were characterized through UV, SEM, XRD, and FTIR. The alpha amylase inhibition and antioxidant activity were checked through α amylase and DPPH radical scavenging assay, respectively. To check the effect of silver nanoparticles on blood glucose levels FBG, IPGTT, ITT tests were employed on STZ induced BALB/c mice. To assess the morphological changes in the anatomy of liver, pancreas, and kidney of BALB/c mice due to silver nanoparticles, histological analysis was done through H&E staining system. Finally, AMPK and IRS1 genes expression analysis was carried out via real time PCR. Silver nanoparticles were found to be spherical in shape with an average size of 42 nm. They showed an IC50 of 8 μg/mL and 10 μg/mL for α amylase and DPPH assay, respectively. Our study suggests that silver nanoparticles—specifically 10 mg/kg—cause a significant increase in the expression of AMPK and IRS1, which ultimately increase the glucose uptake in cells. Thymus serpyllum mediated silver nanoparticles possess strong antioxidant and antidiabetic potential and can further be explored as an effective and cheaper alternative option for treatment of Type 2 Diabetes Mellitus.

Improvement of Glycemic Control by a Functional Food Mixture Containing Maltodextrin, White Kidney Bean Extract, Mulberry Leaf Extract, and Niacin-Bound Chromium Complex in Obese Diabetic db/db Mice

Steady-fiber granule (SFG) is a mixture containing maltodextrin, white kidney bean extract, mulberry leaf extract, and niacin-bound chromium complex. These active ingredients have been shown to be associated with improving either hyperglycemia or hyperlipidemia. This study was undertaken to evaluate the potential of SFG in the regulation of blood glucose homeostasis under obese diabetic conditions. Accordingly, db/db mice (8 weeks old) were administered with SFG at doses of 1.025, 2.05, or 5.125 g/kg BW daily via oral gavage for 4 weeks. No body weight loss was observed after SFG supplementation at all three doses during the experimental period. Supplementation of SFG at 2.05 g/kg BW decreased fasting blood glucose, blood fructosamine, and HbA1c levels in db/db mice. Insulin sensitivity was also improved, as indicated by HOMA-IR assessment and oral glucose tolerance test, although the fasting insulin levels were no different in db/db mice with or without SFG supplementation. Meanwhile, the plasma levels of triglyceride were reduced by SFG at all three doses. These findings suggest that SFG improves glycemic control and insulin sensitivity in db/db mice and can be available as an option for functional foods to aid in management of type 2 diabetes mellitus in daily life.

Health-Promoting and Therapeutic Attributes of Milk-Derived Bioactive Peptides

Milk-derived bioactive peptides (BAPs) possess several potential attributes in terms of therapeutic capacity and their nutritional value. BAPs from milk proteins can be liberated by bacterial fermentation, in vitro enzymatic hydrolysis, food processing, and gastrointestinal digestion. Previous evidence suggested that milk protein-derived BAPs have numerous health-beneficial characteristics, including anti-cancerous activity, anti-microbial activity, anti-oxidative, anti-hypertensive, lipid-lowering, anti-diabetic, and anti-osteogenic. In this literature overview, we briefly discussed the production of milk protein-derived BAPs and their mechanisms of action. Milk protein-derived BAPs are gaining much interest worldwide due to their immense potential as health-promoting agents. These BAPs are now used to formulate products sold in the market, which reflects their safety as natural compounds. However, enhanced commercialization of milk protein-derived BAPs depends on knowledge of their particular functions/attributes and safety confirmation using human intervention trials. We have summarized the therapeutic potentials of these BAPs based on data from in vivo and in vitro studies.

A High-Sugar Diet Consumption, Metabolism and Health Impacts with a Focus on the Development of Substance Use Disorder: A Narrative Review

Carbohydrates are important macronutrients in human and rodent diet patterns that play a key role in crucial metabolic pathways and provide the necessary energy for proper body functioning. Sugar homeostasis and intake require complex hormonal and nervous control to proper body energy balance. Added sugar in processed food results in metabolic, cardiovascular, and nervous disorders. Epidemiological reports have shown enhanced consumption of sweet products in children and adults, especially in reproductive age and in pregnant women, which can lead to the susceptibility of offspring's health to diseases in early life or in adulthood and proneness to mental disorders. In this review, we discuss the impacts of high-sugar diet (HSD) or sugar intake during the perinatal and/or postnatal periods on neural and behavioural disturbances as well as on the development of substance use disorder (SUD). Since several emotional behavioural disturbances are recognized as predictors of SUD, we also present how HSD enhances impulsive behaviour, stress, anxiety and depression. Apart from the influence of HSD on these mood disturbances, added sugar can render food addiction. Both food and addictive substances change the sensitivity of the brain rewarding neurotransmission signalling. The results of the collected studies could be important in assessing sugar intake, especially via maternal dietary patterns, from the clinical perspective of SUD prevention or pre-existing emotional disorders. Methodology: This narrative review focuses on the roles of a high-sugar diet (HSD) and added sugar in foods and on the impacts of glucose and fructose on the development of substance use disorder (SUD) and on the behavioural predictors of drugs abuse. The literature was reviewed by two authors independently according to the topic of the review. We searched the PubMed and Scopus databases and Multidisciplinary Digital Publishing Institute open access scientific journals using the following keyword search strategy depending on the theme of the chapter: "high-sugar diet" OR "high-carbohydrate diet" OR "sugar" OR "glucose" OR "fructose" OR "added sugar" AND keywords. We excluded inaccessible or pay-walled articles, abstracts, conference papers, editorials, letters, commentary, and short notes. Reviews, experimental studies, and epidemiological data, published since 1990s, were searched and collected depending on the chapter structure. After the search, all duplicates are thrown out and full texts were read, and findings were rescreened. After the selection process, appropriate papers were included to present in this review.

MitoTEMPOL Inhibits ROS-Induced Retinal Vascularization Pattern by Modulating Autophagy and Apoptosis in Rat-Injected Streptozotocin Model

Diabetic retinopathy leads to retinal malfunction, blindness, and reduced quality of life in adult diabetes patients. The involvement of reactive oxygen species (ROS) regulation stimulated by high blood glucose levels opens the opportunity for ROS modulator agents such as MitoTEMPOL. This study aims to explore the effect of MitoTEMPOL on ROS balance that may be correlated with retinal vascularization pattern, autophagy, and apoptosis in a streptozotocin-induced rat model. Four groups of male Wistar rats (i.e., control, TEMPOL (100 mg/kg body weight [BW]), diabetic (streptozotocin, 50 mg/kg BW single dose), and diabetic + TEMPOL; n = 5 for each group) were used in the study. MitoTEMPOL was given for 5 weeks, followed by funduscopy, and gene and protein expression were explored from the rat’s retina. Streptozotocin injection decreased bodyweight and increased food and water intake, as well as fasting blood glucose. The results showed that MitoTEMPOL reduced retinal vascularization pattern and decreased superoxide dismutase gene expression and protein carbonyl, caspase 3, and caspase 9 protein levels. A modulation of autophagy in diabetes that was reversed in the diabetic + TEMPOL group was found. In conclusion, MitoTEMPOL modulation on autophagy and apoptosis contributes to its role as a potent antioxidant to prevent diabetic retinopathy by inhibiting ROS-induced retinal vascularization patterns.

Investigation of the Captopril-Insulin Interaction by Mass Spectrometry and Computational Approaches Reveals that Captopril Induces Structural Changes in Insulin

Post-translational modifications remarkably regulate proteins' biological function. Small molecules such as reactive thiols, metabolites, and drugs may covalently modify the proteins and cause structural changes. This study reports the covalent modification and noncovalent interaction of insulin and captopril, an FDA-approved antihypertensive drug, through mass spectrometric and computation-based approaches. Mass spectrometric analysis shows that captopril modifies intact insulin, reduces it into its "A" and "B" chains, and covalently modifies them by forming adducts. Since captopril has a reactive thiol group, it might reduce the insulin dimer or modify it by reacting with cysteine residues. This was proven with dithiothreitol treatment, which reduced the abundance of captopril adducts of insulin A and B chains and intact Insulin. Liquid chromatography tandem mass spectrometric analysis identified the modification of a total of four cysteine residues, two in each of the A and B chains of insulin. These modifications were identified to be Cys6 and Cys7 of the A chain and Cys7 and Cys19 of the B chain. Mass spectrometric analysis indicated that captopril may simultaneously modify the cysteine residues of intact insulin or its subunits A and B chains. Biophysical studies involving light scattering and thioflavin T assay suggested that the binding of captopril to the protein leads to the formation of aggregates. Docking and molecular dynamics studies provided insights into the noncovalent interactions and associated structural changes in insulin. This work is a maiden attempt to understand the detailed molecular interactions between captopril and insulin. These findings suggest that further investigations are required to understand the long-term effect of drugs like captopril.

The Potential Roles of Dietary Anthocyanins in Inhibiting Vascular Endothelial Cell Senescence and Preventing Cardiovascular Diseases

Cardiovascular disease (CVD) is a group of diseases affecting the heart and blood vessels and is the leading cause of morbidity and mortality worldwide. Increasingly more evidence has shown that the senescence of vascular endothelial cells is the key to endothelial dysfunction and cardiovascular diseases. Anthocyanin is a type of water-soluble polyphenol pigment and secondary metabolite of plant-based food widely existing in fruits and vegetables. The gut microbiome is involved in the metabolism of anthocyanins and mediates the biological activities of anthocyanins and their metabolites, while anthocyanins also regulate the growth of specific bacteria in the microbiota and promote the proliferation of healthy anaerobic flora. Accumulating studies have shown that anthocyanins have antioxidant, anti-inflammatory, and anti-aging effects. Many animal and in vitro experiments have also proven that anthocyanins have protective effects on cardiovascular-disease-related dysfunction. However, the molecular mechanism of anthocyanin in eliminating aging endothelial cells and preventing cardiovascular diseases is very complex and is not fully understood. In this systematic review, we summarize the metabolism and activities of anthocyanins, as well as their effects on scavenging senescent cells and cardioprotection.

Exploration of Isoquinoline Alkaloids as Potential Inhibitors against Human Islet Amyloid Polypeptide

Type-2 diabetes mellitus (T2DM) is one of the most concerning public health problems because of its high incidence, multiple complications, and difficult treatment. Human islet amyloid polypeptide (hIAPP) is closely linked to T2DM because its abnormal self-assembly causes membrane damage and cell dysfunction. The development of potential inhibitors to prevent hIAPP fibrillation is a promising strategy for the intervention and treatment of diabetes. Natural isoquinoline alkaloids are used as effective medication that targets different biomolecules. Although studies explored the efficacy of berberine, jatrorrhizine, and chelerythrine in diabetes, the underlying mechanism remains unclear. Herein, three isoquinoline alkaloids are selected to reveal their roles in hIAPP aggregation, disaggregation, and cell protection. All three compounds displayed good inhibitory effects on peptide fibrillation, scattered the preformed fibrils into small oligomers and most monomers, and upregulated cell viability by reducing hIAPP oligomerization. Moreover, combined biophysical analyses indicated that the compounds affected the β-sheet structure and hydrophobicity of polypeptides significantly, and the benzo[c]phenanthridine structure of chelerythrine was beneficial to the inhibition of hIAPP aggregation and their hydrophobic interaction, compared with that of berberine and jatrorrhizine. Our work elaborated the effects of these alkaloids on hIAPP fibrillation and reveals a possible mechanism for these compounds against T2DM.

The cephalic phase of insulin release is modulated by IL-1β

The initial cephalic phase of insulin secretion is mediated through the vagus nerve and is not due to glycemic stimulation of pancreatic β cells. Recently, IL-1β was shown to stimulate postprandial insulin secretion. Here, we describe that this incretin-like effect of IL-1β involves neuronal transmission. Furthermore, we found that cephalic phase insulin release was mediated by IL-1β originating from microglia. Moreover, IL-1β activated the vagus nerve to induce insulin secretion and regulated the activity of the hypothalamus in response to cephalic stimulation. Notably, cephalic phase insulin release was impaired in obesity, in both mice and humans, and in mice, this was due to dysregulated IL-1β signaling. Our findings attribute a regulatory role to IL-1β in the integration of nutrient-derived sensory information, subsequent neuronally mediated insulin secretion, and the dysregulation of autonomic cephalic phase responses in obesity.

Therapeutic potential of dopamine agonists in the treatment of type 2 diabetes mellitus

Diabetes is a global health concern that has affected almost 415 million people globally. Bromocriptine is a dopamine D2 agonist, which is a Food and Drug Administration (FDA)-approved drug to treat type 2 diabetes mellitus (T2DM) patients. However, it is considered that a novel treatment therapy is required which can be used in the treatment of diabetes with or without other antidiabetic agents. Dopamine agonists are usually used in neurological disorders like Parkinson's disease (PD), restless leg syndrome, and hyperprolactinemia. However, dopamine agonists including bromocriptine and cabergoline are also effective in reducing the glycemic level in T2DM patients. Bromocriptine was formerly used for the treatment of PD, hyperprolactinemia, and restless leg syndrome, but now it is used for improving glycemic levels as well as reducing free fatty acids and triglycerides. In addition, cabergoline has been found to be effective in glycemic control, but this drug is yet to be approved by the FDA due to its limitations and lack of study. Findings of the clinical trials of bromocriptine have suggested that it reduces almost 0.4-0.8% glycated hemoglobin and cardiovascular risk by 40% in insulin-resistant patients. Moreover, the safe use of bromocriptine in obese T2DM patients makes it a more attractive option as it causes weight loss. Indeed, bromocriptine is a novel therapy for T2DM patients, as its mechanism of action is unique in T2DM patients with minimal adverse effects. This review summarizes the potential of dopamine agonists in the treatment of T2DM.

The role of MicroRNA networks in tissue-specific direct and indirect effects of metformin and its application

Metformin is a first-line oral antidiabetic agent that results in clear benefits in relation to glucose metabolism and diabetes-related complications. The specific regulatory details and mechanisms underlying these benefits are still unclear and require further investigation. There is recent mounting evidence that metformin has pleiotropic effects on the target tissue development in metabolic organs, including adipose tissue, the gastrointestinal tract and the liver. The mechanism of actions of metformin are divided into direct effects on target tissues and indirect effects via non-targeted tissues. MicroRNAs (miRNAs) are a class of endogenous, noncoding, negative gene regulators that have emerged as important regulators of a number of diseases, including type 2 diabetes mellitus (T2DM). Metformin is involved in many aspects of miRNA regulation, and metformin treatment in T2DM should be associated with other miRNA targets. A large number of miRNAs regulation by metformin in target tissues with either direct or indirect effects has gradually been revealed in the context of numerous diseases and has gradually received increasing attention. This paper thoroughly reviews the current knowledge about the role of miRNA networks in the tissue-specific direct and indirect effects of metformin. Furthermore, this knowledge provides a novel theoretical basis and suggests therapeutic targets for the clinical treatment of metformin and miRNA regulators in the prevention and treatment of cancer, cardiovascular disorders, diabetes and its complications.

Elucidating the Neuroprotective Effect of Tecoma stans Leaf Extract in STZ-Induced Diabetic Neuropathy

Background

Diabetes is considered one of the most encyclopedic metabolic disorders owing to an alarming rise in the number of patients, which is increasing at an exponential rate. With the current therapeutics, which only aims to provide symptomatic and momentary relief, the scientists are shifting gears to explore alternative therapies which not only can target diabetes but can also help in limiting the progression of diabetic complications including diabetic neuropathy (DN).

Methods

Tecoma stans leaf methanolic extract was prepared using the Soxhlet method. A streptozotocin (STZ; 45 mg/kg)-induced diabetic animal model was used and treatment with oral dosing of T. stans leaf extract at the different doses of 200 mg/kg, 300 mg/kg, and highest dose, i.e., 400 mg/kg, was initiated on day 3 after STZ administration. The pharmacological response for general and biochemical (angiogenic, inflammatory, and oxidative) parameters and behavioral parameters were compared using Gabapentin as a standard drug with the results from the test drug.

Results

Parameters associated with the pathogenesis of diabetic neuropathy were evaluated. For general parameters, different doses of T. stans extract (TSE) on blood sugar showed significant effects as compared to the diabetic group. Also, the results from biochemical analysis and behavioral parameters showed significant positive effects in line with general parameters. The combination therapy of TSE at 400 mg/kg with a standard drug produced nonsignificant effects in comparison with the normal group.

Conclusion

The leaves of T. stans possess antidiabetic effects along with promising effects in the management of DN by producing significant effects by exhibiting antioxidative, antiangiogenic, and anti-inflammatory properties, which are prognostic markers for DN, and thus, T. stans can be considered as an emerging therapeutic option for DN.

Prenatal dexamethasone exposure induced pancreatic β-cell dysfunction and glucose intolerance of male offspring rats: Role of the epigenetic repression of ACE2

The prevalence of diabetes in children and adolescents has been rising gradually, which is relevant to adverse environment during development, especially prepartum. We aimed to explore the effects of prenatal dexamethasone exposure (PDE) on β-cell function and glucose homeostasis in juvenile offspring rats. Pregnant Wistar rats were subcutaneously administered with dexamethasone [0.1, 0.2, 0.4mg/(kg.d)] from gestational day 9 to 20. PDE impaired glucose tolerance in the male offspring rather than the females. In male offspring, PDE impaired the development and function of β-cells, accompanied with lower H3K9ac, H3K14ac and H3K27ac levels in the promoter region of angiotensin-converting enzyme 2 (ACE2) as well as suppressed ACE2 expression. Meanwhile, PDE increased expression of glucocorticoid receptor (GR) and histone deacetylase 3 (HDAC3) in fetal pancreas. Dexamethasone also inhibited ACE2 expression and insulin production in vitro. Recombinant expression of ACE2 restored insulin production inhibited by dexamethasone. In addition, dexamethasone activated GR and HDAC3, increased protein interaction of GR with HDAC3, and promoted the binding of GR-HDAC3 complex to ACE2 promoter region. Both RU486 and TSA abolished dexamethasone-induced decline of histone acetylation and ACE2 expression. In summary, suppression of ACE2 is involved in PDE induced β-cell dysfunction and glucose intolerance in juvenile male offspring rats.

The influence of phytochemicals on cell heterogeneity in chronic inflammation-associated diseases: the prospects of single cell sequencing

Chronic inflammation-associated diseases include, but is not limited to cardiovascular disease, cancer, obesity, diabetes, etc. Cell heterogeneity is a prerequisite for understanding the physiological and pathological development of cell metabolism, and its response to external stimuli. Recently, dietary habits based on phytochemicals became increasingly recognized to play a pivotal role in chronic inflammation. Phytochemicals can relieve chronic inflammation by regulating inflammatory cell differentiation and immune cell response, but the influence of phytochemicals on cell heterogeneity from in vitro and ex vivo studies cannot simulate the complexity of cell differentiation in vivo due to the differences in cell lines and extracellular environment. Therefore, there is no consensus on the regulation mechanism of phytochemicals on chronic diseases based on cell heterogeneity. The purpose of this review is to summarize cell heterogeneity in common chronic inflammation-associated diseases and trace the effects of phytochemicals on cell differentiation in chronic diseases development. More importantly, by discussing the problems and challenges which hinder the study of cell heterogeneity in recent nutritional assessment experiments, we propose new prospects based on the drawbacks of existing research to optimize the research on the regulation mechanism of phytochemicals on chronic diseases. The need to explore precise measurements of cell heterogeneity is a key pillar in understanding the influence of phytochemicals on certain diseases. In the future, deeper understanding of cell-to-cell variation and the impact of food components and their metabolites on cell function by single-cell genomics and epigenomics with the focus on individual differences will open new avenues for the next generation of health care.

Insulin Resistance and Urolithiasis as a Challenge for a Dietitian

Many obesity and diet-related diseases have been observed in recent years. Insulin resistance (IR), a state of tissue resistance to insulin due to its impaired function, is a common coexisting condition. The most important predisposing factors are excessive visceral fat and chronic low-grade inflammatory response. However, IR’s pathogenesis is not fully understood. Hence, the diagnosis of IR should be carried out carefully because many different diagnostic paths do not always give equivalent results. An additional disease that is often associated with IR is urolithiasis. The common feature of these two conditions is metabolic acidosis and mild inflammation. A patient diagnosed with IR and urolithiasis is a big challenge for a dietitian. It is necessary to check a thorough dietary history, make an appropriate anthropometric measurement, plan a full-fledged diet, and carry out the correct nutritional treatment. It is also essential to conduct proper laboratory diagnostics to plan nutritional treatment, which is often a big challenge for dietitians. The diet’s basic assumptions are based on the appropriate selection of carbohydrates, healthy fats, and wholesome protein sources. It is also essential to properly compose meals, prepare them, and plan physical activities tailored to the abilities. The study aims to summarise the necessary information on IR with concomitant urolithiasis, which may be helpful in dietary practice.

Punicalagin protects against the development of pancreatic injury and insulitis in rats with induced T1DM by reducing inflammation and oxidative stress

Pancreatic inflammation and oxidative damage remain major concerns in type 1 diabetes mellitus (T1DM). Punicalagin, a major polyphenol in pomegranates, exhibited antioxidant and protective effects on several organs in case of T1DM; however, no study has yet explored the protective effects of punicalagin on the pancreas and islets of Langerhans. T1DM was induced by injecting 40 mg/kg streptozotocin (STZ) intraperitoneally. Punicalagin (1 mg/kg ip) was injected daily for 15 days after T1DM induction. In diabetic rats, punicalagin treatment lowered the levels of inflammatory biomarkers (monocyte chemoattractant protein-1 and C-reactive protein) and adhesion molecules (E-selectin, intercellular adhesion molecule, and vascular cell adhesion molecule) while activating myeloperoxidase activity. Treatment of diabetic rats with punicalagin improved glutathione content and superoxide dismutase, catalase, and glutathione peroxidase activities; upregulated serum paraoxonase-1 activity; and prevented the elevation lipid peroxidation and protein oxidation products in the pancreas. Furthermore, punicalagin protected the pancreas against STZ-induced histopathological alterations and increased immune-reactive β-cells while reducing leucocyte infiltration into the islets of Langerhans, leading to normalized blood glucose and insulin levels. These findings indicated that punicalagin might protect against the development of insulitis in T1DM. In conclusion, punicalagin exerts a strong protective effect on the pancreas against oxidative injury and inflammation in STZ-induced experimental T1DM. The present results recommend punicalagin as a potential adjuvant for reducing diabetes-associated insulitis.

Targeting human Glucokinase for the treatment of type 2 diabetes: an overview of allosteric Glucokinase activators

Diabetes mellitus is a worldwide impacting disorder and the ratio through which the number of diabetic patients had increased worldwide, puts medical professionals to serious stress for its effective management. Due to its polygenic origin and involvement of multiple genes to its pathophysiology, leads to understanding of this ailment more complex. It seems that current interventions, such as dietary changes, life style changes and drug therapy such as oral hypoglycaemics and insulin, are unable to halt the trend. There are various novel and emerging targets on which the researchers are paying attention to combat with this ailment successfully. Human glucokinase (GK) enzyme is one of these novel and emerging targets for management of diabetes. Its availability in the pancreas and liver cells makes this target more lucrative. GK's presence in the pancreatic and hepatic cells plays a very important function for the management of glucose homoeostasis. Small molecules that activate GK allosterically provide an alternative strategy for restoring/improving glycaemic regulation, especially in type 2 diabetic patients. Although after enduring many setbacks in the development of the GK activators, interest has been renewed especially due to introduction of novel dual acting GK activator dorzagliatin, and a novel hepato-selective GK activator, TTP399. This review article has been formulated to discuss importance of GK in glucose homeostasis, recent updates on small molecules of GK activators, clinical status of GK activators and challenges in development of GK activators.