Insulin: too much of a good thing is bad

The impacts of obesity in rheumatoid arthritis and insights into therapeutic purinergic modulation

Rheumatoid Arthritis (RA) is an autoimmune condition responsible for the impairment of synovia and joints, endangering the functionality of individuals and contributing to mortality. Currently, obesity is increasing worldwide, and recent studies have suggested an association between such condition and RA. In this sense, obese individuals present a lower capacity for achieving remission and present more intense symptoms of the disease, demonstrating a link between both disorders. Different studies aim to understand the possible connection between the conditions; however, few is known in this sense. Therefore, knowing that obesity can alter the activity of multiple body systems, this work's objective is to evaluate the main modifications caused by obesity, which can be linked to the pathophysiology of RA, highlighting as relevant topics obesity's negative impact triggering systemic inflammation, intestinal dysbiosis, endocrine disbalances. Furthermore, the relationship between oxidative stress and obesity also deserves to be highlighted, considering the influence of reactive oxygen species (ROS) accumulation in RA exacerbation. Additionally, many of those characteristics influenced by obesity, along with the classic peculiarities of RA pathophysiology, can also be associated with purinergic signaling. Hence, this work suggests possible connections between the purinergic system and RA, proposing potential therapeutic targets against RA to be studied.

Fecal virome transplantation: A promising strategy for the treatment of metabolic diseases

Metabolic diseases are a group of disorders caused by metabolic abnormalities, including obesity, diabetes, non-alcoholic fatty liver disease, and more. Increasing research indicates that, beyond inherent metabolic irregularities, the onset and progression of metabolic diseases are closely linked to alterations in the gut microbiota, particularly gut bacteria. Additionally, fecal microbiota transplantation (FMT) has demonstrated effectiveness in clinically treating metabolic diseases, notably diabetes. Recent attention has also focused on the role of gut viruses in disease onset. This review first introduces the characteristics and influencing factors of gut viruses, then summarizes their potential mechanisms in disease development, highlighting their impact on gut bacteria and regulation of host immunity. We also compare FMT, fecal filtrate transplantation (FFT), washed microbiota transplantation (WMT), and fecal virome transplantation (FVT). Finally, we review the current understanding of gut viruses in metabolic diseases and the application of FVT in treating these conditions. In conclusion, FVT may provide a novel and promising treatment approach for metabolic diseases, warranting further validation through basic and clinical research.

Inhibition of proline-rich tyrosine kinase 2 restores cardioprotection by remote ischaemic preconditioning in type 2 diabetes

BACKGROUND AND PURPOSE

Remote ischaemic preconditioning (rIPC) for cardioprotection is severely impaired in diabetes, and therapeutic options to restore it are lacking. The vascular endothelium plays a key role in rIPC. Given that the activity of endothelial nitric oxide synthase (eNOS) is inhibited by proline-rich tyrosine kinase 2 (Pyk2), we hypothesized that pharmacological Pyk2 inhibition could restore eNOS activity and thus restore remote cardioprotection in diabetes.

EXPERIMENTAL APPROACH

New Zealand obese (NZO) mice that demonstrated key features of diabetes were studied. The consequence of Pyk2 inhibition on endothelial function, rIPC and infarct size after myocardial infarction were evaluated. The impact of plasma from mice and humans with or without diabetes was assessed in isolated buffer perfused murine hearts and aortic rings.

KEY RESULTS

Plasma from nondiabetic mice and humans, both subjected to rIPC, caused remote tissue protection. Similar to diabetic humans, NZO mice demonstrated endothelial dysfunction. NZO mice had reduced circulating nitrite levels, elevated arterial blood pressure and a larger infarct size after ischaemia and reperfusion than BL6 mice. Pyk2 increased the phosphorylation of eNOS at its inhibitory site (Tyr656), limiting its activity in diabetes. The cardioprotective effects of rIPC were abolished in diabetic NZO mice. Pharmacological Pyk2 inhibition restored endothelial function and rescued cardioprotective effects of rIPC.

CONCLUSION AND IMPLICATIONS

Endothelial function and remote tissue protection are impaired in diabetes. Pyk2 is a novel target for treating endothelial dysfunction and restoring cardioprotection through rIPC in diabetes.

The role of IGF/IGF-1R signaling in the regulation of cancer stem cells

Cancer stem cells (CSCs) are a group of tumor cells with high tumorigenic ability and self-renewal potential similar to those of normal stem cells. CSCs are the key "seeds" for tumor development, metastasis, and recurrence. A better insight into the key mechanisms underlying CSC survival improves the efficiency of cancer therapy via specific targeting of CSCs. Insulin-like growth factor (IGF)/IGF-1 receptor (IGF-1R) signaling plays an important role in the maintenance of cancer stemness. However, the effect of IGF/IGF-1R signaling on stemness and CSCs and the underlying mechanisms are still controversial. Based on the similarity between CSCs and normal stem cells, this review discusses emerging data on the functions of IGF/IGF-1R signaling in normal stem cells and CSCs and dissects the underlying mechanisms by which IGF/IGF-1R signaling is involved in CSCs. On the other hand, this review highlighted the role of IGF/IGF-1R signaling blockade in multiple CSCs as a potential strategy to improve CSC-based therapy.

Gluco-regulation & type 2 diabetes: entrenched misconceptions updated to new governing principles for gold standard management

Our understanding of type 2 diabetes (T2D) has evolved dramatically. Advances have upended entrenched dogmas pertaining to the onset and progression of T2D, beliefs that have prevailed from the early era of diabetes research-and continue to populate our medical textbooks and continuing medical education materials. This review article highlights key insights that lend new governing principles for gold standard management of T2D. From the historical context upon which old beliefs arose to new findings, this article outlines evidence and perspectives on beta cell function, the underlying defects in glucoregulation, the remediable nature of T2D, and, the rationale supporting the shift to complication-centric prescribing. Practical approaches translate this rectified understanding of T2D into strategies that fill gaps in current management practices of prediabetes through late type 2 diabetes.

Assessing the impact of body composition, metabolic and oxidative stress parameters on insulin resistance as a prognostic marker for reactive hypoglycemia: a cross-sectional study in overweight, obese, and normal weight individuals

Oxidative stress (OS) plays a pivotal role in the pathogenesis of insulin resistance (IR), particularly in its association with obesity. This study evaluate both the diagnostic and clinical significance of assessing oxidative status in patients affected by overweight and obesity displaying IR, especially with reactive hypoglycemic episodes (RH). A comprehensive examination of OS biomarkers was carried out, encompassing measurements of total oxidative capacity (TOC) and total antioxidant capacity (TAC). Our analysis results reveal noteworthy connections between OS levels and the severity of IR in overweight and obese patients. Moreover, in the study, we demonstrated the diagnostic utility of serum concentrations of TAC and TOC as indicators of the risk of RH, the occurrence of which, even at the stage of overweight, may be associated with increased OS and further development of obesity. Our findings imply that the evaluation of oxidative status could serve as a crucial diagnostic and prognostic tool for patients observed with IR and overweight and obesity. In conclusion, our study underscores the potential utility of assessing oxidative status in the context of IR and highlights the possibility of identifying novel therapeutic targets for the treatment of overweight and obese patients.

Epicardial fat and insulin resistance in healthy older adults: a cross-sectional analysis

Insulin resistance (IR) and cardiovascular diseases (CVD) are relevant concerns in the elderly population; as the world's population ages, IR and CVD are two universal public health problems. While a link between IR a CVD has been established, the mediating mechanisms are uncertain and rigorous investigations are needed to fully elucidate them. The study aimed at assessing the relationship between epicardial fat (EF), an indicator of cardiovascular risk, and IR in Italian free-living elderly (n = 89). Baseline data from a previous cohort was used. Anthropometric measurements, EF, and IR-related variables, including the HOMA-IR index and other biochemical parameters were obtained. The correlation between EF and IR was explored. Further analysis was conducted to identify significant differences regarding IR variables among EF quartiles. EF correlated positively with glucose levels in females, males and the total population. The pairwise comparison among EF quartiles showed significant differences in glucose levels, HOMA-IR index, triglycerides, and total cholesterol levels. To our knowledge, this is the only study assessing the relationship between EF and IR in healthy elderly, while most of the studies have investigated EF and IR in diseased populations. Further research with a longitudinal approach should be conducted to design concrete conclusions about this relationship.

Obesogens: a unifying theory for the global rise in obesity

Despite varied treatment, mitigation, and prevention efforts, the global prevalence and severity of obesity continue to worsen. Here we propose a combined model of obesity, a unifying paradigm that links four general models: the energy balance model (EBM), based on calories as the driver of weight gain; the carbohydrate-insulin model (CIM), based on insulin as a driver of energy storage; the oxidation-reduction model (REDOX), based on reactive oxygen species (ROS) as a driver of altered metabolic signaling; and the obesogens model (OBS), which proposes that environmental chemicals interfere with hormonal signaling leading to adiposity. We propose a combined OBS/REDOX model in which environmental chemicals (in air, food, food packaging, and household products) generate false autocrine and endocrine metabolic signals, including ROS, that subvert standard regulatory energy mechanisms, increase basal and stimulated insulin secretion, disrupt energy efficiency, and influence appetite and energy expenditure leading to weight gain. This combined model incorporates the data supporting the EBM and CIM models, thus creating one integrated model that covers significant aspects of all the mechanisms potentially contributing to the obesity pandemic. Importantly, the OBS/REDOX model provides a rationale and approach for future preventative efforts based on environmental chemical exposure reduction.

Approaching the Sarcopenic Patient with Nonalcoholic Steatohepatitis-related Cirrhosis

Sarcopenia is a well-known complication of chronic liver disease (CLD), and it is almost always observed in patients with cirrhosis, at least in those with decompensated disease. Since nonalcoholic fatty liver disease (NAFLD), recently renamed metabolic dysfunction-associated steatotic liver disease (MASLD), is becoming the leading cause of end-stage liver disease, a new scenario characterized by the frequent coexistence of NAFLD, obesity, and sarcopenia is emerging. Although it is not yet resolved whether the bidirectional relationship between sarcopenia and NAFLD subtends causal determinants, it is clear that the interaction of these two conditions is associated with an increased risk of poor outcomes. Notably, during the course of CLD, deregulation of the liver-muscle-adipose tissue axis has been described. Unfortunately, owing to the lack of properly designed studies, specific therapeutic guidelines for patients with sarcopenia in the context of NAFLD-related CLD have not yet been defined. Strategies aimed to induce the loss of fat mass together with the maintenance of lean body mass seem most appropriate. This can be achieved by properly designed diets integrated with specific nutritional supplementations and accompanied by adequate physical exercise. Future studies aiming to add to the knowledge of the correct assessment and approach to sarcopenia in the context of NAFLD-related CLD are eagerly awaited.

Triple threat: how diabetes results in worsened bacterial infections

Diabetes mellitus, characterized by impaired insulin signaling, is associated with increased incidence and severity of infections. Various diabetes-related complications contribute to exacerbated bacterial infections, including hyperglycemia, innate immune cell dysfunction, and infection with antibiotic-resistant bacterial strains. One defining symptom of diabetes is hyperglycemia, resulting in elevated blood and tissue glucose concentrations. Glucose is the preferred carbon source of several bacterial pathogens, and hyperglycemia escalates bacterial growth and virulence. Hyperglycemia promotes specific mechanisms of bacterial virulence known to contribute to infection chronicity, including tissue adherence and biofilm formation. Foot infections are a significant source of morbidity in individuals with diabetes and consist of biofilm-associated polymicrobial communities. Bacteria perform complex interspecies behaviors conducive to their growth and virulence within biofilms, including metabolic cross-feeding and altered phenotypes more tolerant to antibiotic therapeutics. Moreover, the metabolic dysfunction caused by diabetes compromises immune cell function, resulting in immune suppression. Impaired insulin signaling induces aberrations in phagocytic cells, which are crucial mediators for controlling and resolving bacterial infections. These aberrancies encompass altered cytokine profiles, the migratory and chemotactic mechanisms of neutrophils, and the metabolic reprogramming required for the oxidative burst and subsequent generation of bactericidal free radicals. Furthermore, the immune suppression caused by diabetes and the polymicrobial nature of the diabetic infection microenvironment may promote the emergence of novel strains of multidrug-resistant bacterial pathogens. This review focuses on the "triple threat" linked to worsened bacterial infections in individuals with diabetes: (i) altered nutritional availability in diabetic tissues, (ii) diabetes-associated immune suppression, and (iii) antibiotic treatment failure.

Reinstated Activity of Human Tau-induced Enhanced Insulin Signaling Restricts Disease Pathogenesis by Regulating the Functioning of Kinases/Phosphatases and Tau Hyperphosphorylation in Drosophila

Tauopathies such as Alzheimer's disease (AD), Frontotemporal dementia, and parkinsonism linked to chromosome 17 (FTDP-17), etc. are characterized by tau hyperphosphorylation and distinguished accumulation of paired helical filaments (PHFs)/or neurofibrillary tangles (NFTs) in a specific-neuronal subset of the brain. Among different reported risk factors, type 2 diabetes (T2D) has gained attention due to its correlation with tau pathogenesis. However, mechanistic details and the precise contribution of insulin pathway in tau etiology is still debatable. We demonstrate that expression of human tau causes overactivation of insulin pathway in Drosophila disease models. We subsequently noted that tissue-specific downregulation of insulin signaling or even exclusive reduction of its growth-promoting sub-branch effectively reinstates the overactivated insulin signaling pathway in human tau expressing cells, which in turn restricts pathogenic tau hyperphosphorylation and aggregate formation. It was further noted that restored tau phosphorylation was achieved due to a reestablished balance between the levels of different kinase(s) (GSK3β and ERK/P38 MAP kinase) and phosphatase (PP2A). Taken together, our study demonstrates a precise involvement of the insulin pathway and associated molecular events in the pathogenesis of human tauopathies in Drosophila, which will be immensely helpful in developing novel therapeutic options against these devastating human brain disorders. Moreover, our study reveals an interesting link between tau etiology and aberrant insulin signaling, which is a characteristic feature of Type 2 Diabetes.

Connections between body composition and dysregulation of islet α- and β-cells in type 2 diabetes

BACKGROUND

Accompanying islet α- and β-cell dysregulation in type 2 diabetes (T2D) at the microscopic scale, alterations in body composition at the macroscopic scale may affect the pathogenesis of T2D. However, the connections between body composition and islet α-cell and β-cell functions in T2D have not been thoroughly explored.

METHODS

For this cross-sectional study, we recruited a total of 729 Chinese Han patients with T2D in a consecutive manner. Dual-energy X-ray absorptiometry (DXA) was used to measure body composition, which included total bone-free mass, total fat and lean mass, trunk fat and lean mass and limb fat and lean mass. Every patient underwent an oral glucose tolerance test to simultaneously detect glucose, C-peptide and glucagon. The indices of islet α-cell function included fasting glucagon levels and the area under the curve of glucagon after a challenge (AUCglucagon), while the indices of β-cell function included the insulin sensitivity index derived from C-peptide (ISIC-peptide) and the area under the curve of C-peptide after a challenge (AUCC-peptide).

RESULTS

Among all patients, fat mass, especially trunk fat mass, was significantly correlated with ISIC-peptide and AUCC-peptide levels (r = - 0.330 and 0.317, respectively, p < 0.001), while lean mass, especially limb lean mass, was significantly correlated with fasting glucagon and AUCglucagon levels (r = - 0.196 and - 0.214, respectively, p < 0.001). Moreover, after adjusting for other relevant variables via multivariate linear regression analysis, increased trunk fat mass was independently associated with decreased ISIC-peptide (β = - 0.247, t = - 3.628, p < 0.001, partial R2 = 10.9%) and increased AUCC-peptide (β = 0.229, t = 3.581, p < 0.001, partial R2 = 8.2%), while decreased limb lean mass was independently associated with increased fasting glucagon (β = - 0.226, t = - 2.127, p = 0.034, partial R2 = 3.8%) and increased AUCglucagon (β = - 0.218, t = - 2.050, p = 0.041, partial R2 = 2.3%). Additionally, when separate analyses were performed with the same concept for both sexes, we found that increased trunk fat mass was still independently associated with decreased ISIC-peptide and increased AUCC-peptide, while decreased limb lean mass was still independently associated with increased fasting glucagon and AUCglucagon.

CONCLUSIONS

Increased trunk fat mass may partly account for decreased insulin sensitivity and increased insulin secretion, while decreased limb lean mass may be connected to increased fasting glucagon and postprandial glucagon secretion.

Triglyceride-glucose index is a predictor of the risk of prostate cancer: a retrospective study based on a transprostatic aspiration biopsy population

Background

Current research suggests that prostate cancer (PCa), one of the most common cancers in men, may be linked to insulin resistance (IR).Triglyceride-glucose index (TyG index) was made for a marker of insulin resistance. We investigated the relationship between the TyG index and the risk of PCa.

Objective

To assess the correlation and dose-response relationship between TyG index and prostate cancer.

Method

Retrospectively, 316 patients who required prostate biopsy puncture in the First Affiliated Hospital of Xinjiang Medical University from March 2017 to July 2021 were collected, and the relationship between factors such as the TyG index and prostate cancer was analyzed by Logistic regression model combined with a restricted cubic spline.

Results

(1) The differences in age, initial PSA and TyG index between the two groups were statistically significant; (2) Logistic regression results showed that the risk of prostate cancer in the highest quartile of the TyG index (Q4) was 3.387 times higher than that in the lowest quartile (Q1) (OR=3.387,95% CI [1.511,7.593], P=0.003); (3) The interaction results showed a significant interaction between the TyG index Q4 group and age with the risk of developing prostate cancer (P for interaction<0.001). (4) The results of the restricted cubic spline showed a linear dose-response relationship between the TyG index and the risk of prostate cancer; (5) The Receiver operating characteristic (ROC) curve results showed that the area under the curve (AUC) of the TyG index combined with initial PSA and age was 0.840, with a sensitivity and specificity of 62.5% and 93.3%, respectively.

Conclusion

TyG index and age are risk factors for prostate cancer, and the interaction between the TyG index and different risk factors may increase the risk of prostate cancer. TyG index has some predictive value for the risk of prostate cancer, and the risk of prostate cancer can be reduced by controlling the levels of blood lipids and blood glucose.

Insulin resistance levels predicted metabolic improvement and weight loss after metabolic surgery in Chinese patients with type 2 diabetes

BACKGROUND

The causes for failure of metabolic improvement and inadequate weight loss after metabolic surgery (MS) in Chinese patients with type 2 diabetes (T2D) have not been fully elucidated. The effect of insulin resistance (IR) on the outcome of T2D, hypertension, hyperlipidemia, and obesity after MS in Chinese patients with T2D and a body mass index (BMI) of 25-32.5 kg/m2 warrants further study.

OBJECTIVES

Patients with T2D and a BMI of 25-32.5 kg/m2 who underwent MS between July 2019 and June 2021 were included.

SETTING

University hospital, China.

METHODS

IR levels were evaluated with the glucose disposal rate (GDR). Improvement of T2D, hypertension, and hyperlipidemia was assessed with the composite triple endpoint (CTEP), and weight loss was assessed with the percent of total weight loss (%TWL). Partial correlation analysis, binary logistic regression analysis, multiple linear regression analysis, receiver operating characteristic curve (ROC) analysis, and subgroup analysis were used to analyze the relationship between the CTEP, %TWL at 1 year postoperative, and GDR preoperative.

RESULTS

This study analyzed the data of 51 patients with T2D and a BMI of 25-32.5 kg/m2 (30 men and 21 women) with a mean preoperative GDR of 3.72 ± 1.48 mg/kg/min. Partial correlation coefficients between CTEP, %TWL, and GDR were .303 (P = .041) and .449 (P = .001), respectively. The preoperative GDR was significantly positively correlated with CTEP (OR = 1.610, P = .024) and %TWL (β = 1.38, P = .003). The preoperative GDR predicted cutoff values of 4.36 and 5.35 mg/kg/min for CTEP attainment and %TWL ≥ 20%, respectively.

CONCLUSION

IR levels predicted metabolic improvement and weight loss 1 year after MS in Chinese patients with T2D and a BMI of 25-32.5 kg/m2.

Association of cardiometabolic factors and insulin resistance surrogates with mortality in participants from the Korean Genome and Epidemiology Study

BACKGROUND

Simple biochemical and anthropometric measurements such as fasting blood glucose (FBG), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), waist circumference (WC), and body mass index (BMI) are used to formulate insulin resistance (IR) indices. Whether these indices provide new predictive information for mortality remains unknown. This study examined the relationships of biochemical, anthropometric, and IR indices with mortality risk, as well as their predictive performance.

METHODS

The data source was the Korean Genome and Epidemiology Study (2004-2020) involving 114,957 participants whose data were linked to death records. The IR indices- triglyceride-glucose index (TyG), TyG-BMI, TyG-WC, visceral adiposity index (VAI), lipid accumulation product (LAP), and metabolic score for insulin resistance (METS-IR) were computed using standard formulae. The associations were examined using restricted cubic splines. The predictive performance was compared using the log-likelihood ratio chi-square test.

RESULTS

Body mass index was U-shaped, HDL-C was reverse J-shaped, and FBG and TG levels were J-shaped associated with all-cause mortality. Results showed U-shaped (TyG), J-shaped (TyG-BMI, VAI, LAP, and METS-IR), and reverse J-shaped (TyG-WC) associations with all-cause mortality. The percentages of new predictive information for all-cause mortality explained by the FBG level, BMI, TyG-BMI, and METIR were 3.34%, 2.33%, 1.47%, and 1.37%, respectively. Other IR indices and biochemical and anthropometric measurements provided < 1.0% of new predictive information. For cardiovascular disease mortality, the FBG, BMI, METIR, TyG-BMI, and HDL-C levels explained 2.57%, 2.12%, 1.59%, 1.30%, and 1.27% of new predictive information respectively. Moreover, the risks of cancer mortality explained by FBG level, VAI, and HDL-C level were 2.05%, 1.49%, and 1.28%, respectively.

CONCLUSIONS

Fasting blood glucose level is a superior predictor of mortality risk and may be used as a simple predictive and preventative factor.

Effects of Daily Ingestion of Two SunGold Kiwifruit for 6 Weeks on Metabolic and Inflammatory Biomarkers: A Randomized, Cross-Over, Exploratory Intervention Study

Kiwifruit contain many components, some considered beneficial, such as vitamins, phytochemicals and dietary fibre, and others potentially harmful, such as fructose and glucose in fruit sugars. In a 6-week, randomised, crossover study aimed at exploring the net effects of daily consumption of kiwifruit, 23 healthy participants consumed two Actinidia chinensis var. chinensis 'Zesy002' (marketed as Zespri™ SunGold™ Kiwifruit) per day as part of their customary diet (intervention) or without kiwifruit (control) as their customary diet for 6 weeks in a cross-over study. Anthropometric data, venous blood, and urine samples were collected at the start and end of the 6-week intervention and control periods for the measurement of physical changes, plasma glucose, insulin, glycated haemoglobin, short-chain fatty acids, blood lipids, uric acid, inflammatory biomarkers, and urinary ascorbic acid. Variables were measured between the start and finish of interventions, and between intervention and control periods. Food diaries were completed on the 3 days before blood sampling to estimate dietary ascorbic acid and dietary fibre intakes. Despite urinary vitamin C and food diaries indicating compliance, and good precision in measurements, there were no appreciable changes in biomarkers during the study, either within or between intervention and control periods, that would indicate a change in health status. Thus, the sizes of any effects of kiwifruit ingestion were too small to become significant under the test conditions used, indicating a high probability that daily ingestion of two SunGold kiwifruit is safe with respect to metabolic health.

Quantum Biology and the Potential Role of Entanglement and Tunneling in Non-Targeted Effects of Ionizing Radiation: A Review and Proposed Model

It is well established that cells, tissues, and organisms exposed to low doses of ionizing radiation can induce effects in non-irradiated neighbors (non-targeted effects or NTE), but the mechanisms remain unclear. This is especially true of the initial steps leading to the release of signaling molecules contained in exosomes. Voltage-gated ion channels, photon emissions, and calcium fluxes are all involved but the precise sequence of events is not yet known. We identified what may be a quantum entanglement type of effect and this prompted us to consider whether aspects of quantum biology such as tunneling and entanglement may underlie the initial events leading to NTE. We review the field where it may be relevant to ionizing radiation processes. These include NTE, low-dose hyper-radiosensitivity, hormesis, and the adaptive response. Finally, we present a possible quantum biological-based model for NTE.

IgG and insulin enhance endocytosis in THP-1 cells via activation of phosphatidylinositol 3-kinase (PI3K)

Extracellular substances, including membrane-impermeable nutrients, are taken up by cells via endocytosis. Endocytosis is also an important pathway for antigen uptake by antigen-presenting cells such as monocytes, macrophages, dendritic cells, and B cells. In this study, we investigated the regulatory mechanism of endocytosis in THP-1 cells, a monocytic leukemia cell line. We analyzed the effect of IgG and insulin, which are abundant in the serum and play important roles in immunity and metabolism, respectively, on the endocytic activity in THP-1 cells. The results indicated that IgG and insulin enhance pinocytosis and phagocytosis via activation of phosphatidylinositol 3-kinase (PI3K). Our results suggest that IgG and insulin contribute to the maintenance of endocytic activity and are important for antigen presentation and nutrient uptake.

Insulin and aging - a disappointing relationship

Experimental studies in animal models of aging such as nematodes, fruit flies or mice have observed that decreased levels of insulin or insulin signaling promotes longevity. In humans, hyperinsulinemia and concomitant insulin resistance are associated with an elevated risk of age-related diseases suggestive of a shortened healthspan. Age-related disorders include neurodegenerative diseases, hypertension, cardiovascular disease, and type 2 diabetes. High ambient insulin concentrations promote increased lipogenesis and fat storage, heightened protein synthesis and accumulation of non-functional polypeptides due to limited turnover capacity. Moreover, there is impaired autophagy activity, and less endothelial NO synthase activity. These changes are associated with mitochondrial dysfunction and oxidative stress. The cellular stress induced by anabolic activity of insulin initiates an adaptive response aiming at maintaining homeostasis, characterized by activation of the transcription factor Nrf2, of AMP activated kinase, and an unfolded protein response. This protective response is more potent in the long-lived human species than in short-lived models of aging research resulting in a stronger pro-aging impact of insulin in nematodes and fruit flies. In humans, resistance to insulin-induced cell stress decreases with age, because of an increase of insulin and insulin resistance levels but less Nrf2 activation. These detrimental changes might be contained by adopting a lifestyle that promotes low insulin/insulin resistance levels and enhances an adaptive response to cellular stress, as observed with dietary restriction or exercise.

The effects of Mediterranean diets with low or high glycemic index on plasma glucose and insulin profiles are different in adult men and women: Data from MEDGI-Carb randomized clinical trial

BACKGROUND & AIMS

Recent evidence suggests that the ability to regulate glucose and insulin homeostasis is different in men and women. Against this background, it has been hypothesized that the impact on daily plasma glucose and insulin profiles of the glycemic index (GI) of the habitual diet may differ according to sex. The aim of this study is to evaluate whether 8-h average plasma glucose and insulin profiles during a low- or a high-GI diet in individuals at high risk of developing type 2 diabetes are influenced by sex.

METHODS

We conducted a randomized, controlled, parallel group dietary intervention, comparing high-versus low-GI diets in a multi-national (Italy, Sweden, and the United States) sample of 156 adults at risk for type 2 diabetes. For 12 weeks, 82 vs 74 participants consumed either a low-GI or high-GI Mediterranean diet, respectively. The two experimental diets contained the same quantity of available carbohydrate (270 g/d) and fiber (35 g/d) and the same foods and beverages, except for the major sources of starch that was specific to the low-GI and high-GI groups (pasta, brown rice, flatbread, all bran, and wheat bread plus rye and seeds, vs jasmine rice, potato, couscous, wholegrain bread, and rusks). At baseline and after the intervention plasma glucose and insulin profiles were evaluated for 8 h in the two intervention groups - separately for men and women - with both breakfast and lunch resembling food choices of the assigned diet.

RESULTS

One hundred fifty-six adults (82 women, 74 men) with at least two traits of the metabolic syndrome completed the intervention. In women, the high-GI induced significantly higher (23%, p < 0.05) 8-h average plasma glucose concentrations in comparison to the low-GI diet already on the first day of the intervention; the difference increased up to 37% (p < 0.05) after 12 weeks of diet. Conversely, there were no significant differences between the two diets in men. These results were confirmed by the two-way analysis of variance showing a statistically significant interaction between the effects of sex and diet on the glucose profile after breakfast and lunch (F = 7.887, p = 0.006).

CONCLUSION

The results of our intervention show that women, compared to men, are more sensitive to the metabolic effects of the dietary GI. This has a strong clinical and scientific relevance and, if confirmed in further studies, it might have important implications for dietary strategies for diabetes and cardiovascular disease prevention in the context of personalized nutrition.

REGISTRATION NUMBER OF CLINICAL TRIAL

Clinicaltrials.gov n. NCT03410719.

Supplementary Effects of Allium hookeri Extract on Glucose Tolerance in Prediabetic Subjects and C57BL/KsJ-db/db Mice

Allium hookeri (AH) has been used as a nutritional and medicinal food in Asia for many years. Our previous studies have described its anti-diabetic, anti-obesity, and anti-inflammatory activities in animal models and prediabetes. This study investigated whether AH could improve glycemia by modulating insulin secretion in prediabetic subjects through an in-depth study. Eighty prediabetic subjects (100 ≤ fasting plasma glucose < 140 mg/dL) were randomly assigned to a placebo (n = 40) group or an ethanol AH extract (500 mg/day, n = 40) group for 12 weeks. Dietary intake and physical activity, blood glucose (an oral glucose tolerance test for 120 min), insulin (insulin response to oral glucose for 120 min), area under the curve (AUC) of glucose or insulin after oral glucose intake, insulin sensitivity markers, C-peptide, adiponectin, glycated hemoglobin A1c (HbA1c) levels, hematological tests (WBC, RBC, hemoglobin, hematocrit, and platelet count), blood biochemical parameters (ALP, AST, total bilirubin, total protein, albumin, gamma-GT, BUN, creatinine, LD, CK, and hs-CRP), and urine parameters (specific gravity and pH) were examined at both baseline and 12 weeks after supplementation with placebo or AH capsules. Fifty-eight participants (placebo group: 20 men and 10 women; AH group: 13 men and 15 women) completed the study. AH supplementation moderately reduced postprandial blood glucose at 60 min (-6.14 mg/dL, p = 0.061), postprandial insulin levels at 90 min (-16.69 µU/mL, p = 0.017), the glucose AUC at 90 min (-412.52 mg*min/dL, p = 0.021), as well as the insulin AUC at 90 min (-978.77 µU*min/mL, p = 0.021) and 120 min (-1426.41 µU*min/mL, p = 0.015) when compared with the placebo group. However, there were no effects of AH on dietary intake and physical activity; HOMA index; HbAlc; C-peptide; or adiponectin, hematological-, blood biochemical-, and urinary markers. To confirm the effects of AH extract on blood glucose insulin sensitivity, C57BL/6J or C57BL/KsJ-db/db mice were used (n = 8/group). Body weight, fasting plasma glucose level, lipid profiles, liver and renal function, pancreatic histology, and insulin immunoreactivity were assessed. In the diabetic db/db mice, hyperglycemia, which was accompanied by an increase in insulin secretion in diabetic mice, was significantly reduced by AH treatment, resulting in the alleviation of β-cell overcompensation and insulin resistance. We confirmed that AH supplementation can effectively control blood glucose and insulin levels by improving insulin sensitivity and may be a potential agent for glycemic control in subjects with prediabetes and type 2 diabetes mellitus.

Bitter melon extract suppresses metastatic breast cancer cells (MCF-7 cells) growth possibly by hindering glucose uptake

Breast cancer is one of the most commonly diagnosed cancers among women, however the complete cure for metastatic breast cancer is lacking due to poor prognosis. There has been an increasing trend of dietary modifications including consumption of natural food for the prevention of cancer. One of the popular natural foods is bitter melon. Bitter melon grows in tropical and subtropical areas. Some of the beneficial effects of bitter melon towards disease including cancer have been reported at the whole body/organismal level. However, specific cellular mechanisms by which bitter melon exerts beneficial effects in breast cancer are lacking. In this study, we used a human metastatic breast cancer cell line, MCF-7 cell, to study if bitter melon alters glucose clearance from the culture medium. We co-cultured MCF-7 cells with bitter melon extract in the presence and absence of supplemented insulin and subsequently measured MCF-7 cells viability. In this study, we report a noble finding that bitter melon extract exerts cytotoxic effects on MCF-7 cells possibly via inhibition of glucose uptake. Our findings show that insulin rescues MCF-7 cells from the effects of bitter melon extract.

Advances in research of biological functions of Isthmin-1

Isthmin-1 (ISM1) was initially thought to be a brain secretory factor, but with the development of technical means of research and the refinement of animal models, numerous studies have shown that this molecule is expressed in multiple tissues, suggesting that it may have multiple biological functions. As a factor that regulates growth and development, ISM1 is expressed in different animals with spatial and temporal variability and can coordinate the normal development of multiple organs. Recent studies have found that under the dependence of a non-insulin pathway, ISM1 can lower blood glucose, inhibit insulin-regulated lipid synthesis, promote protein synthesis, and affect the body's glucolipid and protein metabolism. In addition, ISM1 plays an important role in cancer development by promoting apoptosis and anti-angiogenesis, and by regulating multiple inflammatory pathways to influence the body's immune response. The purpose of this paper is to summarize relevant research results from recent years and to describe the key features of the biological functions of ISM1. We aimed to provide a theoretical basis for the study of ISM1 related diseases, and potential therapeutic strategies. The main biological functions of ISM1. Current studies on the biological functions of ISM1 focus on growth and development, metabolism, and anticancer treatment. During embryonic development, ISM1 is dynamically expressed in the zebrafish, African clawed frog, chick, mouse, and human, is associated with craniofacial malformations, abnormal heart localization, and hematopoietic dysfunction. ISM1 plays an important role in regulating glucose metabolism, lipid metabolism, and protein metabolism in the body. ISM1 affects cancer development by regulating cellular autophagy, angiogenesis, and the immune microenvironment.

Gut microbiome-serum metabolic profiles: insight into the hypoglycemic effect of Porphyra haitanensis glycoprotein on hyperglycemic mice

The hypoglycemic activity of natural algal glycoproteins has attracted interest, but studies of their mechanism of regulating glucose metabolism are lacking. This study investigated the hypoglycemic activity of Porphyra haitanensis glycoprotein (PG) in a mouse hyperglycemia model. The underlying mechanism was elucidated by monitoring changes in the gut microbiome and untargeted serum metabolomics. The results indicated that 30-300 mg kg-1 PG regulated blood glucose levels by increasing insulin secretion, reducing glycated hemoglobin, and improving streptozotocin-induced hyperglycemia in a concentration-dependent manner. In particular, 300 mg kg-1 PG decreased fasting blood glucose by 63.11% and glycosylated hemoglobin by 24.50% and increased insulin secretion by 163.97%. The mechanism of the improvement of hyperglycemia by PG may involve regulating beneficial intestinal bacteria (e.g., norank_f__Muribaculaceae and Lachnospiraceae) and altering the serum metabolic profile (e.g., upregulation of hypotaurine, 3-hydroxy-2-naphthoic acid, and L-glycine), to regulate taurine and hypotaurine, the TCA cycle, AMPK, and pyruvate metabolism. Our findings supported the development of Porphyra haitanensis and its glycoprotein as novel natural antidiabetic compounds to regulate the glycemic balance.

Both early and late maternal age at childbirth is associated with increasing odds of central obesity in offspring

OBJECTIVE

Despite studies on offspring obesity and delayed parenthood, little attention has been paid to the central obesity of offspring. The purpose of this study was to test the hypothesis that maternal age at childbirth (MAC) was associated with central obesity in offspring among the adult population, and fasting insulin may play a role in this association as a mediating factor.

METHODS

A total of 423 adults (mean age 37.9 years, 37.1% female) were included. Information about maternal variables and other confounders was collected by face-to-face interview. Waist circumference and insulin were determined through physical measurements and biochemical examinations. Logistic regression model and restricted cubic spline model were used to analyze the relationship between MAC and central obesity of offspring. The mediating effect of fasting insulin levels on association between MAC and offspring waist circumference was also analyzed.

RESULTS

There was a nonlinear relationship between MAC and central obesity in offspring. Compared with subjects with MAC 27-32 years, those with MAC 21-26 years (OR = 1.814, 95% CI: 1.129-2.915) and MAC ≥33 years (OR = 3.337, 95% CI: 1.638-6.798) had higher odds to develop central obesity. Offspring fasting insulin was also higher in MAC 21-26 years and MAC ≥33 years compared with those with MAC 27-32 years. Taking the group MAC 27-32 years as reference, the mediating effect of fasting insulin levels on the waist circumference was 20.6% and 12.4% for MAC 21-26 years and ≥ 33 years, respectively.

CONCLUSION

MAC 27-32 years has the lowest odds of central obesity in offspring. Fasting insulin levels may have a partial mediating effect on the association between MAC and central obesity.

Protective potential of fish oil supplementation against insulin resistance and pancreatic islet damage in STZ-induced Wistar rats

Background

Fish oil, which is regarded as the primary source of omega-3 fatty acids, has been long studied for its potential as an antidiabetic therapy. However, its protective ability against insulin resistance and pancreatic islet alteration remains unclear and controversial.

Aim

To investigate the beneficial effects of fish oil consumption on the progression of insulin resistance and pancreatic islet dysfunction in a rat model of diabetes.

Methods

Diabetic rats model (n = 30) were divided into five groups and received; 1) NS injection + NS oral (normal control); 2) NS injection + 3 g/kg fish oil (fish oil control); 3) streptozotocin (STZ) injection + NS oral [diabetes control (DC)]; 4) STZ injection + 1 g/kg fish oil (DFO1); and 5) STZ injection + 3 g/kg fish oil (DFO3). Fasting blood insulin was analyzed by commercial rat insulin enzyme-linked immunosorbent assay; meanwhile, the determination of insulin sensitivity was calculated by homeostatic model assessment of insulin resistance (HOMA-IR) and homeostatic model assessment of beta-cell function. A histological study was conducted on pancreas tissue using H and E staining.

Results

Fish oil supplementation reduced hyperglycemia and ameliorated HOMA-IR in STZ-induced animal models indicating that fish oil supplementation improved insulin sensitivity. Furthermore, animals treated with fish oil at a dose of 3 g/kg (DFO3) showed an enhancement in pancreatic islets, which was displayed by less abnormal structures than DC animals. This could imply that the administration of fish oil, especially rich in bioactive omega-3 fatty acids effectively inhibits insulin resistance and restore islet of Langerhans alteration in rats injected with STZ.

Conclusion

Thus, the current study suggested that fish oil supplementation could support the treatment of diabetes but should not be considered as an alternative therapy.

Composition of the intestinal microbiota and its variations between the second and third trimesters in women with gestational diabetes mellitus and without gestational diabetes mellitus

Objective

This study was designed to explore the composition of the intestinal microbiota and its longitudinal variation between the second trimester (T2) and the third trimester (T3) in women with gestational diabetes mellitus (GDM) and pregnant women with normal glucose tolerance.

Methods

This observational study was conducted at Peking Union Medical College Hospital (PUMCH). Women with GDM and pregnant women with normal glucose tolerance were enrolled in the study, and fecal samples were collected during T2 (weeks 24~28) and T3 (weeks 34~38). Fecal samples were analyzed from 49 women with GDM and 42 pregnant women with normal glucose tolerance. The 16S rRNA gene amplicon libraries were sequenced to analyze the microbiota and QIIME2 was used to analyze microbiome bioinformatics.

Results

The four dominant phyla that Firmicutes, Bacteroidetes, Actinobacteria and Proteobacteria which accomplish about 99% of the total relative abundance did not significantly change between the T2 and T3 in the GDM and healthy groups. At the genus level, the relative abundance of Scardovia (0 vs. 0.25%, P = 0.041) and Propionibacterium (0 vs. 0.29%, P = 0.041) increased significantly in the control group, but not in the GDM group. At the phylum level, the relative abundance of Firmicutes and Actinobacteria was significantly different between women with GDM and pregnant women with normal glucose tolerance in both T2 and T3. In T2 and T3, the relative abundances of unidentified_Lachnospiraceae, Blautia, and Parabacteroides were significantly higher in the GDM group than in the control group (P<0.05). The relative abundance of Bifidobacterium in the GDM group was lower than in the control group in both T2 and T3.

Conclusions

The intestinal microbiota composition was stable from T2 to T3 in the GDM and control groups; however, the intestinal microbiota composition was different between the two groups.

Normal-weight visceral obesity promotes a higher 10-year atherosclerotic cardiovascular disease risk in patients with type 2 diabetes mellitus-a multicenter study in China

BACKGROUND

Visceral obesity is associated with high cardiovascular events risk in type 2 diabetes mellitus (T2DM). Whether normal-weight visceral obesity will pose a higher atherosclerotic cardiovascular disease (ASCVD) risk than body mass index (BMI)-defined overweight or obese counterparts with or without visceral obesity remains unclear. We aimed to explore the relationship between general obesity and visceral obesity and 10-year ASCVD risk in patients with T2DM.

METHODS

Patients with T2DM (6997) who satisfied the requirements for inclusion were enrolled. Patients were considered to have normal weight when 18.5 kg/m² ≤ BMI < 24 kg/m²; overweight when 24 kg/m² ≤ BMI < 28 kg/m²; and obesity when BMI ≥ 28 kg/m². Visceral obesity was defined as a visceral fat area (VFA) ≥ 100 cm². Patients were separated into six groups based on BMI and VFA. The odd ratios (OR) for a high 10-year ASCVD risk for different combinations of BMI and VFA were analysed using stepwise logistic regression. Receiver operating characteristic (ROC) curves for diagnosing the high 10-year ASCVD risk were constructed, and areas under the ROC curves were estimated. Potential non-linear relationships between VFA levels and high 10-year ASCVD risk were examined using restricted cubic splines (knot = 4). Multilinear regression was used to identify factors affecting VFA in patients with T2DM.

RESULTS

In patients with T2DM, subjects with normal-weight visceral obesity had the highest 10-year ASCVD risk among the six groups, which had more than a 2-fold or 3-fold higher OR than those who were overweight or obese according to BMI but did not have visceral obesity (all P < 0.05). The VFA threshold for high 10-year ASCVD risk was 90 cm². Multilinear regression showed significant differences in the effect of age, hypertension, drinking, fasting serum insulin, fasting plasma glucose, 2 h postprandial C-peptide, triglyceride, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol on VFA in patients with T2DM (all P < 0.05).

CONCLUSIONS

T2DM patients with normal-weight visceral obesity had a higher 10-year ASCVD risk than BMI-defined overweight or obese counterparts with or without visceral obesity, which should initiate standardised management for ASCVD primary prevention.

Molecular Mechanisms for the Vicious Cycle between Insulin Resistance and the Inflammatory Response in Obesity

The comprehensive anabolic effects of insulin throughout the body, in addition to the control of glycemia, include ensuring lipid homeostasis and anti-inflammatory modulation, especially in adipose tissue (AT). The prevalence of obesity, defined as a body mass index (BMI) ≥ 30 kg/m², has been increasing worldwide on a pandemic scale with accompanying syndemic health problems, including glucose intolerance, insulin resistance (IR), and diabetes. Impaired tissue sensitivity to insulin or IR paradoxically leads to diseases with an inflammatory component despite hyperinsulinemia. Therefore, an excess of visceral AT in obesity initiates chronic low-grade inflammatory conditions that interfere with insulin signaling via insulin receptors (INSRs). Moreover, in response to IR, hyperglycemia itself stimulates a primarily defensive inflammatory response associated with the subsequent release of numerous inflammatory cytokines and a real threat of organ function deterioration. In this review, all components of this vicious cycle are characterized with particular emphasis on the interplay between insulin signaling and both the innate and adaptive immune responses related to obesity. Increased visceral AT accumulation in obesity should be considered the main environmental factor responsible for the disruption in the epigenetic regulatory mechanisms in the immune system, resulting in autoimmunity and inflammation.

Next-generation human adipose tissue culture methods

White adipocytes are highly specialized, lipid-storing cells. Their unique characteristics, including their large cell size and high buoyancy, have made adipocytes hard to study in vitro. Most traditional monolayered adipocyte culture models also poorly reflect the morphology and expression of their mature counterparts. The recent invent of 3D adipocyte cultures seems to circumvent many of these shortcomings, and holds promise of improved adipocyte studies in vitro. Notable advances include vascularized and immunocompetent 3D adipose tissue models and organ-on-a-chip models. This short review aims to highlight some of the most recent advances, as well as discussing what challenges still lie ahead in order to develop culture models that are easily applicable, while adequately reflecting the characteristics of human adipose tissue.

Five-Year Changes in Inflammatory, Metabolic, and Oxidative Biomarkers and 10-Year Cardiovascular Disease Incidence: The REGICOR Cohort Study

Ischemic cardiovascular diseases (CVD) originate from an imbalance between atherosclerotic plaque formation, instability, and endothelial healing dynamics. Our aim was to examine the relationship between 5-year changes in inflammatory, metabolic, and oxidative biomarkers and 10-year CVD incidence in a population without previous CVD. This was a prospective cohort study of individuals aged 35-74 years (n = 419) randomly selected from 5263 REGICOR participants without CVD recruited in 2005. Biomarkers were measured at baseline and in 2010. Participants were followed up until 2020 for a composite CVD endpoint including coronary artery disease, stroke, and peripheral artery disease. We used Cox regression to analyze the effect of biomarker levels on the occurrence of the composite endpoint, adjusted for traditional CVD risk factors and baseline levels of each biomarker. Individuals with elevated IL-6 or insulin after 5 years had a higher independent risk of CVD at 10 years, compared to those with lower levels. Each rise of 1 pg/mL of IL-6 or 10 pg/mL of insulin increased the 10-year risk of a CVD event by 32% and 2%, respectively. Compared to a model with traditional CVD risk factors only, the inclusion of IL-6 and insulin improved continuous reclassification by 51%. Elevated serum levels of IL-6 and insulin were associated with a higher risk of CVD at 10 years, independently of traditional CVD risk factors.

Respiratory Outcomes of Insulin Use in Patients with COPD: A Nationwide Population-Based Cohort Study

Acute exacerbations of chronic obstructive pulmonary disease (COPD) with severe hyperglycemia may require insulin to lower glucose levels in people with coexisting type 2 diabetes (T2D) and COPD. We conducted this study to examine the risk of hospitalization for COPD, pneumonia, ventilator use, lung cancer, hypoglycemia, and mortality with and without insulin use in people with T2D and COPD. We adopted propensity-score-matching to identify 2370 paired insulin users and non-users from Taiwan's National Health Insurance Research Database between 1 January 2000 and 31 December 2018. Cox proportional hazards models and the Kaplan-Meier method were utilized to compare the risk of outcomes between study and control groups. The mean follow-up for insulin users and non-users was 6.65 and 6.37 years. Compared with no insulin use, insulin use was associated with a significantly increased risk of hospitalization for COPD (aHR 1.7), bacterial pneumonia (aHR 2.42), non-invasive positive pressure ventilation (aHR 5.05), invasive mechanical ventilation (aHR 2.72), and severe hypoglycemia (aHR 4.71), but with no significant difference in the risk of death. This nationwide cohort study showed that patients with T2D and COPD requiring insulin therapy may have an increased risk of acute COPD exacerbations, pneumonia, ventilator use, and severe hypoglycemia without a significant increase in the risk of death.

Hepatic Insulin Resistance Model in the Male Wistar Rat Using Exogenous Insulin Glargine Administration

Metabolic diseases are a worldwide health problem. Insulin resistance (IR) is their distinctive hallmark. For their study, animal models that provide reliable information are necessary, permitting the analysis of the cluster of abnormalities that conform to it, its progression, and time-dependent molecular modifications. We aimed to develop an IR model by exogenous insulin administration. The effective dose of insulin glargine to generate hyperinsulinemia but without hypoglycemia was established. Then, two groups (control and insulin) of male Wistar rats of 100 g weight were formed. The selected dose (4 U/kg) was administered for 15, 30, 45, and 60 days. Zoometry, a glucose tolerance test, insulin response, IR, and the serum lipid profile were assessed. We evaluated insulin signaling, glycogenesis and lipogenesis, redox balance, and inflammation in the liver. Results showed an impairment of glucose tolerance, dyslipidemia, hyperinsulinemia, and peripheral and time-dependent selective IR. At the hepatic level, insulin signaling was impaired, resulting in reduced hepatic glycogen levels and triglyceride accumulation, an increase in the ROS level with MAPK-ERK1/2 response, and mild pro-oxidative microenvironmental sustained by MT, GSH, and GR activity. Hepatic IR coincides with additions in MAPK-p38, NF-κB, and zoometric changes. In conclusion, daily insulin glargine administration generated a progressive IR model. At the hepatic level, the IR was combined with oxidative conditions but without inflammation.

Intermittent fasting attenuates obesity-related atrial fibrillation via SIRT3-mediated insulin resistance mitigation

OBJECTIVE

Atrial fibrillation (AF) is the most common tachyarrhythmia in urgent need of therapeutic optimization. Obesity engenders AF, and its pathogenesis is closely intertwined with insulin resistance (IR), but mechanism-based management is still underinvestigated. Intermittent fasting (IF) is a novel lifestyle intervention that mitigates IR, a potential AF driver, yet whether IF can prevent obesity-related AF remains elusive. Here, we aimed to evaluate the impacts of short-term IF on AF and to uncover the underlying mechanism.

METHODS

We subjected obese mice (high-fat diet for 8-week) to IF (alternative-day fasting for another 5-week) for AF vulnerability and substrate formation assessment, and similarly treated neonatal atrial cardiomyocytes (NRCMs) and fibroblasts (NRCFs) (palmitate, 200 μM) with IF (alternative-day short-term starvation for 8-day) for mechanism investigation.

RESULTS

Obese mice were prone to AF and atrial remodeling. IF reduced AF inducibility, duration, and reversed atrial remodeling including channel disturbance, left atrial dilation, cardiac hypertrophy and fibrosis in obese mice independent of weight loss. Mechanistically, IF up-regulated the SIRT3 protein level both in vivo and in vitro, and pharmacologic inhibition (3-(1H-1,2,3-Triazol-4-yl) pyridine, 50 μM) and genetic suppression of SIRT3 could attenuate the IF-mediated benefits against hypertrophy and fibrosis. Furthermore, IF activated AMPK and Akt signaling, two positive downstream targets of SIRT3, and inactivated HIF1α signaling, a negative downstream target of SIRT3 in both obese mice atria and palmitate-treated cells, while inhibition of SIRT3 reversed these effects.

CONCLUSION

IF prevents obesity-related AF via SIRT3-mediated IR mitigation, thus representing a feasible lifestyle intervention to improve AF management.

Impact of a Low-Insulin-Stimulating Bread on Weight Development-A Real Life Randomised Controlled Trial

The impact on body weight development is usually analysed by comparing different diet types. Our approach was to change only one component, namely bread, common to most diets. In a single-centre triple-blind randomised controlled trial the effects of two different breads on body weight were analyzed without further lifestyle modification. Overweight adult volunteers (n = 80) were randomised 1:1 to exchange previously consumed breads for either a rye bread from milled whole grain (control) or a medium-carbohydrate, low-insulin-stimulating bread (intervention). Pre-tests demonstrated that the two bread types strongly differed in the glucose and insulin response elicited, but had similar energy content, texture and taste. The primary endpoint was the estimated treatment difference (ETD) in change of body weight after 3 months of treatment. Whereas body weight remained unchanged in the control group (-0.1 ± 2.0 kg), significant weight reduction was observed in the intervention group (-1.8 ± 2.9 kg), with an ETD of -1.7 ± 0.2 kg (p = 0.007), that was more pronounced in participants ≥ 55 years (-2.6 ± 3.3 kg), paralleled by significant reductions in body mass index and hip circumference. Moreover, in the intervention group, the percentage of participants with significant weight loss (≥1 kg) was twice as high as in the control group (p < 0.001). No other statistically significant changes in clinical or lifestyle parameters were noted. Simply exchanging a common insulinogenic bread for a low-insulin-stimulating bread demonstrates potential to induce weight loss in overweight persons, especially those at older age.

Insulin Infusion Dosing in Pediatric Diabetic Ketoacidosis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

In children with diabetic ketoacidosis (DKA), insulin infusions are the mainstay of treatment; however, optimal dosing remains unclear. Our objective was to compare the efficacy and safety of different insulin infusion doses for the treatment of pediatric DKA.

DATA SOURCES

We searched MEDLINE, EMBASE, PubMed, and Cochrane from inception to April 1, 2022.

STUDY SELECTION

We included randomized controlled trials (RCTs) of children with DKA comparing intravenous insulin infusion administered at 0.05 units/kg/hr (low dose) versus 0.1 units/kg/hr (standard dose).

DATA EXTRACTION

We extracted data independently and in duplicate and pooled using a random effects model. We assessed the overall certainty of evidence for each outcome using the Grading Recommendations Assessment, Development and Evaluation approach.

DATA SYNTHESIS

We included four RCTs (n = 190 participants). In children with DKA, low-dose compared with standard-dose insulin infusion probably has no effect on time to resolution of hyperglycemia (mean difference [MD], 0.22 hr fewer; 95% CI, 1.19 hr fewer to 0.75 hr more; moderate certainty), or time to resolution of acidosis (MD, 0.61 hr more; 95% CI, 1.81 hr fewer to 3.02 hr more; moderate certainty). Low-dose insulin infusion probably decreases the incidence of hypokalemia (relative risk [RR], 0.65; 95% CI, 0.47-0.89; moderate certainty) and hypoglycemia (RR, 0.37; 95% CI, 0.15-0.80; moderate certainty), but may have no effect on rate of change of blood glucose (MD, 0.42 mmol/L/hr slower; 95% CI, 1 mmol/L/hr slower to 0.18 mmol/L/hr faster; low certainty).

CONCLUSIONS

In children with DKA, the use of low-dose insulin infusion is probably as efficacious as standard-dose insulin, and probably reduces treatment-related adverse events. Imprecision limited the certainty in the outcomes of interest, and the generalizability of the results is limited by all studies being performed in a single country.

Profound Sensitivity of the Liver to the Direct Effect of Insulin Allows Peripheral Insulin Delivery to Normalize Hepatic but Not Muscle Glucose Uptake in the Healthy Dog

Endogenous insulin secretion is a key regulator of postprandial hepatic glucose metabolism, but this process is dysregulated in diabetes. Subcutaneous insulin delivery alters normal insulin distribution, causing relative hepatic insulin deficiency and peripheral hyperinsulinemia, a major risk factor for metabolic disease. Our aim was to determine whether insulin's direct effect on the liver is preeminent even when insulin is given into a peripheral vein. Postprandial-like conditions were created (hyperinsulinemia, hyperglycemia, and a positive portal vein to arterial glucose gradient) in healthy dogs. Peripheral (leg vein) insulin infusion elevated arterial and hepatic levels 8.0-fold and 2.8-fold, respectively. In one group, insulin's full effects were allowed. In another, insulin's indirect hepatic effects were blocked with the infusion of triglyceride, glucagon, and inhibitors of brain insulin action (intracerebroventricular) to prevent decreases in plasma free fatty acids and glucagon, while blocking increased hypothalamic insulin signaling. Despite peripheral insulin delivery the liver retained its full ability to store glucose, even when insulin's peripheral effects were blocked, whereas muscle glucose uptake markedly increased, creating an aberrant distribution of glucose disposal between liver and muscle. Thus, the healthy liver's striking sensitivity to direct insulin action can overcome the effect of relative hepatic insulin deficiency, whereas excess insulin in the periphery produces metabolic abnormalities in nonhepatic tissues.

Different ratios of DHA/EPA reverses insulin resistance by improving adipocyte dysfunction and lipid disorders in HFD-induced IR mice

Objective: Insulin resistance (IR) is linked to the development of diabetes, non-alcoholic fatty liver disease (NAFLD), and cardiovascular disease (CVDs). Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) from fish oils (FOs) were used to investigate their potential in high-fat diet (HFD)-induced IR mice under different ratios. Methods: A total of 84 male C57BL/6J (6 weeks old) mice were fed with HFD containing 45% kcal from fat for 16 weeks to establish the IR model. The IR mice were then fed with HFD or HFD + 4% DHA/EPA with different ratios (3 : 1, 1.5 : 1, 1 : 1, 1 : 1.5, 1 : 3, respectively) for another 12 weeks. During the experiment, the CON group (n = 12) was set to feed with a basic diet containing 10% kcal from fat. Results: HFD feeding for 16 weeks reduced insulin sensitivity and accelerated hypertrophy of white adipose tissue (WAT). Different ratios of DHA/EPA except for 1 : 1 decreased the HOMA-IR index, average area of adipocytes, and serum MDA, but increased the protein expression of PI3K. All ratios of DHA/EPA increased the protein expression of IRS-1, GLUT4, and adiponectin. Moreover, dietary DHA/EPA changed serum fatty acid (FA) composition by increasing the serum concentration of n-3 PUFAs. DHA/EPA supplements also improved serum lipid profiles (TG/TC/LDL-c/HDL-c, FFA) and reduced the hepatic steatosis area. Conclusions: The results indicate that an appropriate higher ratio of DHA (1.5 : 1) in DHA/EPA supplementation is recommended for IR prevention.

A nonlinear associations of metabolic score for insulin resistance index with incident diabetes: A retrospective Chinese cohort study

Background

The Metabolic score of insulin resistance (METS-IR) has recently been accepted as a reliable alternative to insulin resistance (IR), which was demonstrated to be consistent with the hyperinsulinemic-euglycemic clamp. Few pieces of research have focused on the relationship between METS-IR and diabetes in Chinese. The purpose of this research was to explore the effect of METS-IR on new-onset diabetes in a large multicenter Chinese study.

Methods

At the baseline of this retrospective longitudinal research, 116855 participators were included in the Chinese cohort study administered from 2010 to 2016. The subjects were stratified by quartiles of METS-IR. To assess the effect of METS-IR on incident diabetes, the Cox regression model was constructed in this study. Stratification analysis and interaction tests were applied to detect the potential effect of METS-IR and incident diabetes among multiple subgroups. To verify whether there was a dose-response relationship between METS-IR and diabetes, a smooth curve fitting was performed. In addition, to further determine the performance of METS -IR in predicting incident diabetes, the receiver operating characteristic curve (ROC) was conducted.

Results

The average age of the research participators was 44.08 ± 12.93 years, and 62868 (53.8%) were men. METS-IR were significant relationship with new-onset diabetes after adjusting for possible variables (Hazard ratio [HR]: 1.077; 95% confidence interval [CI]: 1.073-1.082, P &lt; 0.0001), the onset risk for diabetes in Quartile 4 group was 6.261-fold higher than those in Quartile 1 group. Moreover, stratified analyses and interaction tests showed that interaction was detected in the subgroup of age, body mass index, systolic blood pressure, diastolic blood pressure, and fasting plasma glucose, there was no significant interaction between males and females. Furthermore, a dose-response correlation was detected between METS-IR and incident diabetes, the nonlinear relationship was revealed and the inflection point of METS-IR was calculated to be 44.43. When METS-IR≥44.43, compared with METS-IR &lt; 44.43, the trend was gradually saturated, with log-likelihood ratio test P &lt; 0.001. Additionally, the area under receiver operating characteristic of the METS-IR in predicting incident diabetes was 0.729, 0.718, and 0.720 at 3, 4, and 5 years, respectively.

Conclusions

METS-IR was correlated with incident diabetes significantly, and showed a nonlinear relationship. This study also found that METS-IR had good discrimination of diabetes.

Uncovering the effect and mechanism of Panax notoginseng saponins on metabolic syndrome by network pharmacology strategy

ETHNOPHARMACOLOGICAL RELEVANCE

Metabolic syndrome (MetS) is a cluster of disease centered on obesity, which is the result of stagnation of liver qi according to traditional Chinese medicine. Panax notoginseng is a traditional Chinese herbal medicine, entering liver and stomach meridians and dissipating blood stasis, in which panax notoginseng saponins (PNS) are the main active components. However, its effects and mechanism on metabolic syndrome has not been revealed yet.

AIM OF STUDY

To evaluate the anti-MetS effect of PNS, including body weight and adiposity, glucose metabolism and non-alcoholic fatty liver disease (NAFLD), as well as to explore the mechanism and signaling pathway of PNS on MetS effect.

MATERIALS AND METHODS

HPLC was utilized to affirm the percentages of saponins in PNS. In vivo, normal C57BL/6J mice and high-fat diet (HFD)-induced MetS mice were used to evaluate anti-MetS effect of PNS. Body weight, food and water intake were recorded. NMR imager was used for NMR imaging and lipid-water analysis. Blood glucose detection, glucose and insulin tolerance test were performed to evaluate glucose metabolism. Biochemical indexes analysis and histopathological staining were used to evaluate the effect on NAFLD. The expressions of mRNA and proteins related to thermogenesis in adipose tissue were determined using real-time PCR and Western blot. In silico, network pharmacology was utilized to predict potential mechanism. In vitro, matured 3T3-L1 adipocyte was used as subject to confirm the signaling pathway by Western blot.

RESULTS

We determined the content of PNS component by HPLC. In vivo, PNS could improve metabolic syndrome with weight loss, reduction of adiposity, improvement of adipose distribution, correction of glucose metabolism disorder and attenuation of NAFLD. Mechanismly, PNS boosted energy exhaustion and dramatically enhanced thermogenesis in brown adipose tissue (BAT), induced white adipose tissue (WAT) browning. In silico, utilizing network pharmacology strategy, we identified 307 candidate targets which were enriched in MAPK signaling pathway specifically in liver tissue and adipocyte. In vitro validation confirmed ERK and p38MAPK mediated anti-MetS effects of PNS, not JNK signaling pathway.

CONCLUSION

PNS exerted protective effect on metabolic syndrome through MAPK-mediated adipose thermogenic activation, which may serve as a prospective therapeutic drug for metabolic syndrome.

Current Insights on the Use of Insulin and the Potential Use of Insulin Mimetics in Targeting Insulin Signalling in Alzheimer's Disease

Alzheimer's disease (AD) and type 2 diabetes (T2D) are chronic diseases that share several pathological mechanisms, including insulin resistance and impaired insulin signalling. Their shared features have prompted the evaluation of the drugs used to manage diabetes for the treatment of AD. Insulin delivery itself has been utilized, with promising effects, in improving cognition and reducing AD related neuropathology. The most recent clinical trial involving intranasal insulin reported no slowing of cognitive decline; however, several factors may have impacted the trial outcomes. Long-acting and rapid-acting insulin analogues have also been evaluated within the context of AD with a lack of consistent outcomes. This narrative review provided insight into how targeting insulin signalling in the brain has potential as a therapeutic target for AD and provided a detailed update on the efficacy of insulin, its analogues and the outcomes of human clinical trials. We also discussed the current evidence that warrants the further investigation of the use of the mimetics of insulin for AD. These small molecules may provide a modifiable alternative to insulin, aiding in developing drugs that selectively target insulin signalling in the brain with the aim to attenuate cognitive dysfunction and AD pathologies.

Glucose-Induced Hemodynamic and Metabolic Response of Skeletal Muscle in Heart Failure Patients with Reduced vs. Preserved Ejection Fraction-A Pilot Study

(1) Background: Insulin resistance (IR) is a characteristic pathophysiologic feature in heart failure (HF). We tested the hypothesis that skeletal muscle metabolism is differently impaired in patients with reduced (HFrEF) vs. preserved (HFpEF) ejection fraction. (2) Methods: carbohydrate and lipid metabolism was studied in situ by intramuscular microdialysis in patients with HFrEF (59 ± 14y, NYHA I-III) and HFpEF (65 ± 10y, NYHA I-II) vs. healthy subjects of similar age during the oral glucose load (oGL); (3) Results: There were no difference in fasting serum and interstitial parameters between the groups. Blood and dialysate glucose increased significantly in HFpEF vs. HFrEF and controls upon oGT (both p < 0.0001), while insulin increased significantly in HFrEF vs. HFpEF and controls (p < 0.0005). Muscle tissue perfusion tended to be lower in HFrEF vs. HFpEF and controls after the oGL (p = 0.057). There were no differences in postprandial increases in dialysate lactate and pyruvate. Postprandial dialysate glycerol was higher in HFpEF vs. HFrEF and controls upon oGL (p = 0.0016); (4) Conclusion: A pattern of muscle glucose metabolism is distinctly different in patients with HFrEF vs. HFpEF. While postprandial IR was characterized by impaired tissue perfusion and higher compensatory insulin secretion in HFrEF, reduced muscle glucose uptake and a blunted antilipolytic effect of insulin were found in HFpEF.

Dietary restriction in senolysis and prevention and treatment of disease

Aging represents a key risk factor for a plethora of diseases. Targeting detrimental processes which occur during aging, especially before onset of age-related disease, could provide drastic improvements in healthspan. There is increasing evidence that dietary restriction (DR), including caloric restriction, fasting, or fasting-mimicking diets, extend both lifespan and healthspan. This has sparked interest in the use of dietary regimens as a non-pharmacological means to slow aging and prevent disease. Here, we review the current evidence on the molecular mechanisms underlying DR-induced health improvements, including removal of senescent cells, metabolic reprogramming, and epigenetic rejuvenation.

Role of miR-379 in high-fat diet-induced kidney injury and dysfunction

Obesity is associated with increased risk for diabetes and damage to the kidneys. Evidence suggests that miR-379 plays a role in the pathogenesis of diabetic kidney disease. However, its involvement in obesity-induced kidney injury is not known and was therefore investigated in this study by comparing renal phenotypes of high-fat diet (HFD)-fed wild-type (WT) and miR-379 knockout (KO) mice. Male and female WT mice on the HFD for 10 or 24 wk developed obesity, hyperinsulinemia, and kidney dysfunction manifested by albuminuria and glomerular injuries. However, these adverse alterations in HFD-fed WT mice were significantly ameliorated in HFD-fed miR-379 KO mice. HFD feeding increased glomerular expression of miR-379 and decreased its target gene, endoplasmic reticulum (ER) degradation enhancing α-mannosidase-like protein 3 (Edem3), a negative regulator of ER stress. Relative to the standard chow diet-fed controls, expression of profibrotic transforming growth factor-β1 (Tgf-β1) was significantly increased, whereas Zeb2, which encodes ZEB2, a negative regulator of Tgf-β1, was decreased in the glomeruli in HFD-fed WT mice. Notably, these changes as well as HFD-induced increased expression of other profibrotic genes, glomerular hypertrophy, and interstitial fibrosis in HFD-fed WT mice were attenuated in HFD-fed miR-379 KO mice. In cultured primary glomerular mouse mesangial cells (MMCs) isolated from WT mice, treatment with high insulin (mimicking hyperinsulinemia) increased miR-379 expression and decreased its target, Edem3. Moreover, insulin also upregulated Tgf-β1 and downregulated Zeb2 in WT MMCs, but these changes were significantly attenuated in MMCs from miR-379 KO mice. Together, these experiments revealed that miR-379 deletion protects mice from HFD- and hyperinsulinemia-induced kidney injury at least in part through reduced ER stress.NEW & NOTEWORTHY miR-379 knockout mice are protected from high-fat diet (HFD)-induced kidney damage through key miR-379 targets associated with ER stress (Edem3). Mechanistically, treatment of mesangial cells with insulin (mimicking hyperinsulinemia) increased expression of miR-379, Tgf-β1, miR-200, and Chop and decreases Edem3. Furthermore, TGF-β1-induced fibrotic genes are attenuated by a GapmeR targeting miR-379. The results implicate a miR-379/EDEM3/ER stress/miR-200c/Zeb2 signaling pathway in HFD/obesity/insulin resistance-induced renal dysfunction. Targeting miR-379 with GapmeRs can aid in the treatment of obesity-induced kidney disease.

Progression from prediabetes to type 2 diabetes mellitus induced by overnutrition

Prediabetes has developed into a global pandemic, its prevalence increasing year by year. Although lifestyle changes are advocated as the basis for prediabetes treatment, some patients fail to choose or adhere to appropriate interventions. The basis for selecting an appropriate intervention is determining the stage and cause of the disease. In this review, we aimed to examine the various types and disease processes of prediabetes caused by overnutrition, the present review supporting the hypothesis that overnutrition-induced hyperinsulinemia precedes insulin resistance (IR) and independently causes β-cell dysfunction. Tissue insulin resistance is the main feature of prediabetes with the crosstalk between tissues promoting the formation of systemic insulin resistance. Finally, both β-cell dysfunction induced by hyperinsulinemia or IR and reduced β-cell mass can lead to abnormal insulin secretion and contribute to development of type 2 diabetes mellitus (T2DM). Hence, overnutrition can cause multiple prediabetes phenotypes resulting in development of T2DM through different trajectories. Future diagnosis and treatment should therefore more carefully consider the disease phenotype and stage of development in patients with prediabetes to reduce the incidence of T2DM.

Effect of chronic administration of 17β-estradiol on the vasopressor responses induced by the sympathetic nervous system in insulin resistance rats

Several studies have demonstrated that the underlying mechanism of insulin resistance (IR) is linked with developing diseases like diabetes mellitus, hypertension, metabolic syndrome, and polycystic ovary syndrome. In turn, the dysfunction of female gonadal hormones (especially 17β-estradiol) may be related to the development of IR complications since different studies have shown that 17β-estradiol has a cardioprotector and vasorelaxant effect. This study aimed was to determine the effect of the 17β-estradiol administration in insulin-resistant rats and its effects on cardiovascular responses in pithed rats. Thus, the vasopressor responses are induced by sympathetic stimulation or i.v. bolus injections of noradrenaline (α_1/2), methoxamine (α₁), and UK 14,304 (α₂) adrenergic agonist were determined in female pithed rats with fructose-induced insulin resistance or control rats treated with: 1) 17β-estradiol or 2) its vehicle (oil) for 5 weeks. Thus, 17β-estradiol decreased heart rate, prevented the increase of blood pressure induced by ovariectomy, but with the opposite effect on sham-operated rats; and decreased vasopressor responses induced by i.v. bolus injections of noradrenaline on sham-operated (control and fructose group) and ovariectomized (control) rats, and those induced by i.v. bolus injections of methoxamine (α₁ adrenergic agonist). Overall, these results suggest 17β-estradiol has a cardioprotective effect, and its effect on vasopressor responses could be mediated mainly by the α1 adrenergic receptor. In contrast, IR with ovariectomy 17β-estradiol decreases or loses its cardioprotector effect, this could suggest a possible link between the adrenergic receptors and the insulin pathway.

Bioengineered Pancreas-Liver Crosstalk in a Microfluidic Coculture Chip Identifies Human Metabolic Response Signatures in Prediabetic Hyperglycemia

Aberrant glucose homeostasis is the most common metabolic disturbance affecting one in ten adults worldwide. Prediabetic hyperglycemia due to dysfunctional interactions between different human tissues, including pancreas and liver, constitutes the largest risk factor for the development of type 2 diabetes. However, this early stage of metabolic disease has received relatively little attention. Microphysiological tissue models that emulate tissue crosstalk offer emerging opportunities to study metabolic interactions. Here, a novel modular multitissue organ-on-a-chip device is presented that allows for integrated and reciprocal communication between different 3D primary human tissue cultures. Precisely controlled heterologous perfusion of each tissue chamber is achieved through a microfluidic single "synthetic heart" pneumatic actuation unit connected to multiple tissue chambers via specific configuration of microchannel resistances. On-chip coculture experiments of organotypic primary human liver spheroids and intact primary human islets demonstrate insulin secretion and hepatic insulin response dynamics at physiological timescales upon glucose challenge. Integration of transcriptomic analyses with promoter motif activity data of 503 transcription factors reveals tissue-specific interacting molecular networks that underlie β-cell stress in prediabetic hyperglycemia. Interestingly, liver and islet cultures show surprising counter-regulation of transcriptional programs, emphasizing the power of microphysiological coculture to elucidate the systems biology of metabolic crosstalk.