Moderate Intensity Training Impact on the Inflammatory Status and Glycemic Profiles in NOD Mice

Obesity-induced tissue alterations resist weight loss: A mechanistic review

Interventions aimed at weight control often have limited effectiveness in combating obesity. This review explores how obesity-induced dysfunction in white (WAT) and brown adipose tissue (BAT), skeletal muscle, and the brain blunt weight loss, leading to retention of stored fat. In obesity, increased adrenergic stimulation and inflammation downregulate β-adrenoreceptors and impair catecholaminergic signalling in adipocytes. This disrupts adrenergic-mediated lipolysis, diminishing lipid oxidation in both white and brown adipocytes, lowering thermogenesis and blunting fat loss. Emerging evidence suggests that WAT fibrosis is associated with worse weight loss outcomes; indeed, limiting collagen and laminin-α4 deposition mitigates WAT accumulation, enhances browning, and protects against high-fat-diet-induced obesity. Obesity compromises mitochondrial oxidative capacity and lipid oxidation in skeletal muscle, impairing its ability to switch between glucose and lipid metabolism in response to varying nutrient levels and exercise. This dysfunctional phenotype in muscle is exacerbated in the presence of obesity-associated sarcopenia. Additionally, obesity suppresses sarcolipin-induced sarcoplasmic reticulum calcium ATPase (SERCA) activation, resulting in reduced oxidative capacity, diminished energy expenditure, and increased adiposity. In the hypothalamus, obesity and overnutrition impair insulin and leptin signalling. This blunts central satiety signals, favouring a shift in energy balance toward energy conservation and body fat retention. Moreover, both obese animals and humans demonstrate impaired dopaminergic signalling and diminished responses to nutrient intake in the striatum, which tend to persist after weight loss. This may result in enduring inclinations toward overeating and a sedentary lifestyle. Collectively, the tissue adaptations described pose significant challenges to effectively achieving and sustaining weight loss in obesity.

Exercise Restores Hypothalamic Health in Obesity by Reshaping the Inflammatory Network

Obesity and overnutrition induce inflammation, leptin-, and insulin resistance in the hypothalamus. The mediobasal hypothalamus responds to exercise enabling critical adaptions at molecular and cellular level that positively impact local inflammation. This review discusses the positive effect of exercise on obesity-induced hypothalamic dysfunction, highlighting the mechanistic aspects related to the anti-inflammatory effects of exercise. In HFD-fed animals, both acute and chronic moderate-intensity exercise mitigate microgliosis and lower inflammation in the arcuate nucleus (ARC). Notably, this associates with restored leptin sensitivity and lower food intake. Exercise-induced cytokines IL-6 and IL-10 mediate part of these positive effect on the ARC in obese animals. The reduction of obesity-associated pro-inflammatory mediators (e.g., FFAs, TNFα, resistin, and AGEs), and the improvement in the gut-brain axis represent alternative paths through which regular exercise can mitigate hypothalamic inflammation. These findings suggest that the regular practice of exercise can restore a proper functionality in the hypothalamus in obesity. Further analysis investigating the crosstalk muscle-hypothalamus would help toward a deeper comprehension of the subject.

hUCMSCs carrying exenatide prevent T1DM by improving intestinal microflora composition and islet tissue damage repair

BACKGROUND

Exenatide is a stable analogue of glucagon-like peptide 1 that can reduce postprandial hyperglycemia and has been utilized as adjunctive therapy for type 1 diabetes mellitus (T1DM). The human umbilical cord is a rich source of MSCs, and human umbilical cord mesenchymal stem cells (hUCMSCs) also show potential to enhance insulin secretion. Here, we aimed to explore the effects of hUCMSCs carrying exenatide in T1DM and further identify the possible mechanisms involved.

METHODS

hUCMSCs were isolated from human umbilical cord tissues, identified, and transduced with recombinant lentivirus carrying exenatide to obtain exenatide-carrying hUCMSCs (hUCMSCs@Ex-4).

RESULTS

The results showed that hUCMSCs@Ex-4 restored the blood glucose levels and body weight of NOD mice, and repressed immune cell infiltration and islet tissue changes. Additionally, in T1DM mice, treatment with hUCMSCs@Ex-4 reduced the blood glucose levels and promoted repair of islet tissue damage. Moreover, hUCMSCs@Ex-4 attenuated renal tissue lesions in T1DM mice. Applying bioinformatic analysis, the effects of hUCMSCs@Ex-4 were suggested to correlate with decreased abundance of pro-inflammatory intestinal bacteria and increased abundance of anti-inflammatory intestinal bacteria.

CONCLUSION

Overall, the study indicated that hUCMSCs carrying exenatide might improve beneficial intestinal microflora abundance and promote islet tissue damage repair, thereby alleviating T1DM.

Gut Microbiome Changes in Gestational Diabetes

Gestational diabetes mellitus (GDM), one of the most common endocrine pathologies during pregnancy, is defined as any degree of glucose intolerance with onset or first discovery in the perinatal period. Physiological changes that occur in pregnant women can lead to inflammation, which promotes insulin resistance. In the general context of worldwide increasing obesity in young females of reproductive age, GDM follows the same ascending trend. Changes in the intestinal microbiome play a decisive role in obesity and the development of insulin resistance and chronic inflammation, especially in patients with type 2 diabetes mellitus (T2D). To date, various studies have also associated intestinal dysbiosis with metabolic changes in women with GDM. Although host metabolism in women with GDM has not been fully elucidated, it is of particular importance to analyze the available data and to discuss the actual knowledge regarding microbiome changes with potential impact on the health of pregnant women and newborns. We analyzed peer-reviewed journal articles available in online databases in order to summarize the most recent findings regarding how variations in diet and metabolic status of GDM patients can contribute to alteration of the gut microbiome, in the same way that changes of the gut microbiota can lead to GDM. The most frequently observed alteration in the microbiome of patients with GDM was either an increase of the Firmicutes phylum, respectively, or a decrease of the Bacteroidetes and Actinobacteria phyla. Gut dysbiosis was still present postpartum and can impact the development of the newborn, as shown in several studies. In the evolution of GDM, probiotic supplementation and regular physical activity have the strongest evidence of proper blood glucose control, favoring fetal development and a healthy outcome for the postpartum period. The current review aims to summarize and discuss the most recent findings regarding the correlation between GDM and dysbiosis, and current and future methods for prevention and treatment (lifestyle changes, pre- and probiotics administration). To conclude, by highlighting the role of the gut microbiota, one can change perspectives about the development and progression of GDM and open up new avenues for the development of innovative therapeutic targets in this disease.

Resistance Training Improves Beta Cell Glucose Sensing and Survival in Diabetic Models

Resistance training increases insulin secretion and beta cell function in healthy mice. Here, we explored the effects of resistance training on beta cell glucose sensing and survival by using in vitro and in vivo diabetic models. A pancreatic beta cell line (INS-1E), incubated with serum from trained mice, displayed increased insulin secretion, which could be linked with increased expression of glucose transporter 2 (GLUT2) and glucokinase (GCK). When cells were exposed to pro-inflammatory cytokines (in vitro type 1 diabetes), trained serum preserved both insulin secretion and GCK expression, reduced expression of proteins related to apoptotic pathways, and also protected cells from cytokine-induced apoptosis. Using 8-week-old C57BL/6 mice, turned diabetic by multiple low doses of streptozotocin, we observed that resistance training increased muscle mass and fat deposition, reduced fasting and fed glycemia, and improved glucose tolerance. These findings may be explained by the increased fasting and fed insulinemia, along with increased beta cell mass and beta cell number per islet, observed in diabetic-trained mice compared to diabetic sedentary mice. In conclusion, we believe that resistance training stimulates the release of humoral factors which can turn beta cells more resistant to harmful conditions and improve their response to a glucose stimulus.

Influencing Factors of Students Aged 10–20 Non-participating in Home Physical Exercise During the COVID-19 Isolation Policy Period: A Cross-Sectional Study From China

Background

A number of public health measures are required during the COVID-19 pandemic. To stop the spread of COVID-19, the Chinese government has adopted isolation policies, including closing non-essential businesses, public transportation and schools, moving students' face-to-face learning to online, and recommending the cancellation of all non-essential activities and outdoor activities. However, while this isolation strategy has reduced human-to-human transmission of COVID-19, it has led to dramatic changes in students' daily lives and learning styles, including reduced physical activity and increased sedentary time. Considering the potentially harmful effects of physical inactivity, this study hoped to explore the incidence and influencing factors of non-participation in home physical exercise among Chinese students aged 10–20 during the implementation of the COVID-19 isolation policy.

Methods

Through an online questionnaire platform, this study created an open-ended questionnaire (from March 1, 2020 to March 10, 2020) and distributed it to students in areas where isolation policies were enforced. The questionnaire was initially distributed by 10 recruited volunteers, and then the questionnaire was voluntarily forwarded and shared by the subjects or others, in a “snowball” way, to expand distribution. Finally, the survey data of 4,532 Chinese students aged 10–20 were collected. The incidence of respondents non-participating in home physical activity was determined using univariate analysis. Using odds ratios and 95% confidence intervals of a multivariate binary logistic regression model, factors influencing non-participation in home physical exercise were estimated.

Results

Among the sample students, the incidence rate of non-participating in home physical exercise was 25.86% (24.06–27.15%). Exercise intentions, exercise habits, self-assessed health, beliefs in physical health, family exercise, family exercise recommendations, home exercise conditions, school exercise guidance, and health education programs had a negative impact on students non-participating in home physical exercise. Academic performance and electronic product use had a positive effect on non-participating in home physical exercise.

Conclusions

A variety of forward leaning factors, enabling factors and demand factors have affected the occurrence of students” non-participating in home physical exercise. Future health isolation policies should take into account these influencing factors to reduce the occurrence of students” non-participating in home physical exercise and to promote students' independent participation in physical exercise.

Exercise as Treatment for Neuropathy in the Setting of Diabetes and Prediabetic Metabolic Syndrome: A Review of Animal Models and Human Trials

BACKGROUND

Peripheral neuropathy is among the most common complications of diabetes, but a phenotypically identical distal sensory predominant, painful axonopathy afflicts patients with prediabetic metabolic syndrome, exemplifying a spectrum of risk and continuity of pathogenesis. No pharmacological treatment convincingly improves neuropathy in the setting of metabolic syndrome, but evolving data suggest that exercise may be a promising alternative.

OBJECTIVE

The aim of the study was to review in depth the current literature regarding exercise treatment of metabolic syndrome neuropathy in humans and animal models, highlight the diverse mechanisms by which exercise exerts beneficial effects, and examine adherence limitations, safety aspects, modes and dose of exercise.

RESULTS

Rodent models that recapitulate the organismal milieu of prediabetic metabolic syndrome and the phenotype of its neuropathy provide a strong platform to dissect exercise effects on neuropathy pathogenesis. In these models, exercise reverses hyperglycemia and consequent oxidative and nitrosative stress, improves microvascular vasoreactivity, enhances axonal transport, ameliorates the lipotoxicity and inflammatory effects of hyperlipidemia and obesity, supports neuronal survival and regeneration following injury, and enhances mitochondrial bioenergetics at the distal axon. Prospective human studies are limited in scale but suggest exercise to improve cutaneous nerve regenerative capacity, neuropathic pain, and task-specific functional performance measures of gait and balance. Like other heath behavioral interventions, the benefits of exercise are limited by patient adherence.

CONCLUSION

Exercise is an integrative therapy that potently reduces cellular inflammatory state and improves distal axonal oxidative metabolism to ameliorate features of neuropathy in metabolic syndrome. The intensity of exercise need not improve cardinal features of metabolic syndrome, including weight, glucose control, to exert beneficial effects.

Exercise Enhanced Cardiac Function in Mice With Radiation-Induced Heart Disease via the FNDC5/Irisin-Dependent Mitochondrial Turnover Pathway

Background: Despite the development of radiation therapy (RT) techniques, concern regarding the serious and irreversible heart injury induced by RT has grown due to the lack of early intervention measures. Although exercise can act as an effective and economic nonpharmacologic strategy to combat fatigue and improve quality of life for cancer survivors, limited data on its application in radiation-induced heart disease (RIHD) and the underlying molecular mechanism are available.

Methods: Fifteen young adult male mice were enrolled in this study and divided into 3 groups (including exercised RIHD group, sedentary RIHD group, and controls; n =5 samples/group). While the mice in the control group were kept in cages without irradiation, those in the exercised RIHD group underwent 3weeks of aerobic exercise on the treadmill after radiotherapy. At the end of the 3rd week following RT, FNDC5/irisin expression, cardiac function, aerobic fitness, cardiomyocyte apoptosis, mitochondrial function, and mitochondrial turnover in the myocardium were assessed to identify the protective role of exercise in RIHD and investigate the potential mechanism.

Results: While sedentary RIHD group had impaired cardiac function and aerobic fitness than controls, the exercised RIHD mice had improved cardiac function and aerobic fitness, elevated ATP production and the mitochondrial protein content, decreased mitochondrial length, and increased formation of mitophagosomes compared with sedentary RIHD mice. These changes were accompanied by the elevated expression of FNDC5/irisin, a fission marker (DRP1) and mitophagy markers (PINK1 and LC3B) in exercised RIHD group than that of sedentary RIHD group, but the expression of biogenesis (TFAM) and fusion (MFN2) markers was not significantly changed.

Conclusion: Exercise could enhance cardiac function and aerobic fitness in RIHD mice partly through an autocrine mechanism via FNDC5/irisin, in which autophagy was selectively activated, suggesting that FNDC5/irisin may act as an intervening target to prevent the development of RIHD.

Antimicrobial photodynamic therapy (aPDT) with curcumin controls intradermal infection by Staphylococcus aureus in mice with type 1 diabetes mellitus: a pilot study

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the main pathogens that cause infections in diabetic individuals. In this paper, we report the outcomes of our investigation on the intradermal application of antimicrobial photodynamic therapy (PDT) with curcumin in an infection induced by MRSA ATCC 43300 strain in the ear of mice with Type 1 Diabetes Mellitus (T1DM). A solution containing 100 μg of curcumin was photoactivated ex vivo with a LED light (450 nm) delivering a fluency of 13.5 J/cm³. This solution was administered in the ear intradermally, at the same inoculum site as the MRSA ATCC 43300 strain (PDT Group). This study also included the use of two control groups (both infected): One was treated with saline and the other was treated with non-photoactivated curcumin. The animals were euthanized 24 h after these treatments and samples of draining lymph node and treated ear were collected for examination. The PDT group showed lower bacterial load in the draining lymph node when compared to the saline and curcumin groups (p-value <0.05) 24 h after treatment. In addition to bacterial load, the PDT group presented a higher concentration of nitrates and nitrites in the draining lymph node when compared to the saline and curcumin groups (p-value <0.001). Examining the infectious site, despite apparently having similar inflammatory cell recruitment compared with the control groups, the PDT group showed a profile with less intense activity in the myeloperoxidase expression when compared to the saline group (p-value <0.001). Additionally, the detected concentration of cytokines such as IL-1β, IL-12, and IL-10 was significantly lower in the PDT group when compared to the saline group (p-value <0.01; p-value <0.05; p-value <0.05, respectively), thus presenting a less intense inflammatory response during infection resolution. Our pilot study showed for the first time the therapeutic potential of PDT using curcumin when administered intradermally in the treatment of infections caused by S. aureus in mice with T1DM.

Exercise tolls the bell for key mediators of low-grade inflammation in dysmetabolic conditions

Metabolic conditions share a common low-grade inflammatory milieu, which represents a key-factor for their ignition and maintenance. Exercise is instrumental for warranting systemic cardio-metabolic balance, owing to its regulatory effect on inflammation. This review explores the effect of physical activity in the modulation of sub-inflammatory framework characterizing dysmetabolic conditions. Regular exercise suppresses plasma levels of TNFα, IL-1β, FFAs and MCP-1, in dysmetabolic subjects. In addition, a single session of training increases the anti-inflammatory IL-10, IL-1 receptor antagonist (IL-1ra), and muscle-derived IL-6, mitigating low-grade inflammation. Resting IL-6 levels are decreased in trained-dysmetabolic subjects, compared to sedentary. On the other hand, the acute release of muscle-IL-6, after exercise, seems to exert a regulatory effect on the metabolic and inflammatory balance. In fact, muscle-released IL-6 is presumably implicated in fat loss and boosts plasma levels of IL-10 and IL-1ra. The improvement of adipose tissue functionality, following regular exercise, is also critical for the mitigation of sub-inflammation. This effect is likely mediated by muscle-released IL-15 and IL-6 and partly relies on the brown-shifting of white adipocytes, induced by exercise. In obese-dysmetabolic subjects, moderate training is shown to restore gut-microbiota health, and this mitigates the translocation of bacterial-LPS into bloodstream. Finally, regular exercise can lower plasma advanced glycated endproducts. The articulated physiology of circulating mediators and the modulating effect of the pathophysiological background, render the comprehension of the exercise-regulatory effect on sub-inflammation a key issue, in dysmetabolism.

The Role of the α Cell in the Pathogenesis of Diabetes: A World beyond the Mirror

Type 2 Diabetes Mellitus (T2DM) is one of the most prevalent chronic metabolic disorders, and insulin has been placed at the epicentre of its pathophysiological basis. However, the involvement of impaired alpha (α) cell function has been recognized as playing an essential role in several diseases, since hyperglucagonemia has been evidenced in both Type 1 and T2DM. This phenomenon has been attributed to intra-islet defects, like modifications in pancreatic α cell mass or dysfunction in glucagon's secretion. Emerging evidence has shown that chronic hyperglycaemia provokes changes in the Langerhans' islets cytoarchitecture, including α cell hyperplasia, pancreatic beta (β) cell dedifferentiation into glucagon-positive producing cells, and loss of paracrine and endocrine regulation due to β cell mass loss. Other abnormalities like α cell insulin resistance, sensor machinery dysfunction, or paradoxical ATP-sensitive potassium channels (KATP) opening have also been linked to glucagon hypersecretion. Recent clinical trials in phases 1 or 2 have shown new molecules with glucagon-antagonist properties with considerable effectiveness and acceptable safety profiles. Glucagon-like peptide-1 (GLP-1) agonists and Dipeptidyl Peptidase-4 inhibitors (DPP-4 inhibitors) have been shown to decrease glucagon secretion in T2DM, and their possible therapeutic role in T1DM means they are attractive as an insulin-adjuvant therapy.

Lipotoxicity and Diabetic Nephropathy: Novel Mechanistic Insights and Therapeutic Opportunities

Lipotoxicity is characterized by the ectopic accumulation of lipids in organs different from adipose tissue. Lipotoxicity is mainly associated with dysfunctional signaling and insulin resistance response in non-adipose tissue such as myocardium, pancreas, skeletal muscle, liver, and kidney. Serum lipid abnormalities and renal ectopic lipid accumulation have been associated with the development of kidney diseases, in particular diabetic nephropathy. Chronic hyperinsulinemia, often seen in type 2 diabetes, plays a crucial role in blood and liver lipid metabolism abnormalities, thus resulting in increased non-esterified fatty acids (NEFA). Excessive lipid accumulation alters cellular homeostasis and activates lipogenic and glycogenic cell-signaling pathways. Recent evidences indicate that both quantity and quality of lipids are involved in renal damage associated to lipotoxicity by activating inflammation, oxidative stress, mitochondrial dysfunction, and cell-death. The pathological effects of lipotoxicity have been observed in renal cells, thus promoting podocyte injury, tubular damage, mesangial proliferation, endothelial activation, and formation of macrophage-derived foam cells. Therefore, this review examines the recent preclinical and clinical research about the potentially harmful effects of lipids in the kidney, metabolic markers associated with these mechanisms, major signaling pathways affected, the causes of excessive lipid accumulation, and the types of lipids involved, as well as offers a comprehensive update of therapeutic strategies targeting lipotoxicity.

The benefits of physical exercise for the health of the pancreatic β-cell: a review of the evidence

NEW FINDINGS

What is the topic of this review? This review discusses the evidence of the benefits of exercise training for β-cell health through improvements in function, proliferation and survival which may have implications in the treatment of diabetes. What advances does it highlight? This review highlights how exercise may modulate β-cell health in the context of diabetes and highlights the need for further exploration of whether β-cell preserving effects of exercise translates to T1D.

ABSTRACT

Physical exercise is a core therapy for type 1 and type 2 diabetes. Whilst the benefits of exercise for different physiological systems are recognised, the effect of exercise specifically on the pancreatic β-cell is not well described. Here we review the effects of physical exercise on β-cell health. We show that exercise improves β-cell mass and function. The improved function manifests primarily through the increased insulin content of the β-cell and its increased ability to secrete insulin in response to a glucose stimulus. We review the evidence relating to glucose sensing, insulin signalling, β-cell proliferation and β-cell apoptosis in humans and animal models with acute exercise and following exercise training programmes. Some of the mechanisms through which these benefits manifest are discussed.

L-carnitine supplementation attenuates NAFLD progression and cardiac dysfunction in a mouse model fed with methionine and choline-deficient diet

Non-alcoholic fatty liver disease (NAFLD) is a common cause of chronic liver disorder. NAFLD, associated lipotoxicity, fibrosis, oxidative stress, and altered mitochondrial metabolism, is responsible for systemic inflammation, which contributes to organ dysfunction in extrahepatic tissues, including the heart. We investigated the ability of L-carnitine (LC) to oppose the pathogenic mechanisms underlying NAFLD progression and associated heart dysfunction, in a mouse model of methionine-choline-deficient diet (MCDD). Mice were divided into three groups: namely, the control group (CONTR) fed with a regular diet and two groups fed with MCDD for 6 weeks. In the last 3 weeks, one of the MCDD groups received LC (200 mg/kg each day) through drinking water (MCDD + LC). The hepatic lipid accumulation and oxidative stress decreased after LC supplementation, which also reduced hepatic fibrosis via modulation of α-smooth muscle actin (αSMA), peroxisome-activated receptor gamma (PPARγ), and nuclear factor kappa B (NfƙB) expression. LC ameliorated systemic inflammation, mitigated cardiac reactive oxygen species (ROS) production, and prevented fibrosis progression by acting on signal transducer and activator of transcription 3 (STAT3), extracellular signal-regulated kinase 1-2 (ERK1-2), and αSMA. This study confirms the existence of a relationship between fatty liver disease and cardiac abnormalities and highlights the role of LC in controlling liver oxidative stress, steatosis, fibrosis, and NAFLD-associated cardiac dysfunction.

The Interplay between Immune System and Microbiota in Diabetes

Diabetes is not a single and homogeneous disease, but a cluster of metabolic diseases characterized by the common feature of hyperglycemia. The pathogenesis of type 1 diabetes (T1D) and type 2 diabetes (T2D) (and all other intermediate forms of diabetes) involves the immune system, in terms of inflammation and autoimmunity. The past decades have seen an increase in all types of diabetes, accompanied by changes in eating habits and consequently a structural evolution of gut microbiota. It is likely that all these events could be related and that gut microbiota alterations might be involved in the immunomodulation of diabetes. Thus, gut microbiota seems to have a direct, even causative role in mediating connections between the environment, food intake, and chronic disease. As many conditions that increase the risk of diabetes modulate gut microbiota composition, it is likely that immune-mediated reactions, induced by alterations in the composition of the microbiota, can act as facilitators for the onset of diabetes in predisposed subjects. In this review, we summarize recent evidence in the field of gut microbiota and the role of the latter in modulating the immune reactions involved in the pathogenesis of diabetes.

Sex-dependent effects of bisphenol A on type 1 diabetes development in non-obese diabetic (NOD) mice

Type 1 diabetes (T1D) is an autoimmune disease caused by immune-mediated pancreatic β-cell destruction. The endocrine disrupting chemical bisphenol A (BPA) has widespread human exposure and can modulate immune function and the gut microbiome (GMB), which may contribute to the increasing T1D incidence worldwide. It was hypothesized that BPA had sex-dependent effects on T1D by modulating immune homeostasis and GMB. Adult female and male non-obese diabetic (NOD) mice were orally administered BPA at environmentally relevant doses (30 or 300 µg/kg). Antibiotic-treated adult NOD females were exposed to 0 or 30 µg/kg BPA. BPA accelerated T1D development in females, but delayed males from T1D. Consistently, females had a shift towards pro-inflammation (e.g., increased macrophages and Bacteroidetes), while males had increases in anti-inflammatory immune factors and a decrease in both anti- and pro-inflammatory GMB. Although bacteria altered during sub-acute BPA exposure differed from bacteria altered from chronic BPA exposure in both sexes, the GMB profile was consistently pro-inflammatory in females, while males had a general decrease of both anti- and pro-inflammatory gut microbes. However, treatment of females with the antibiotic vancomycin failed to prevent BPA-induced glucose intolerance, suggesting changes in Gram-positive bacteria were not a primary mechanism. In conclusion, BPA exposure was found to have sex dimorphic effects on T1D with detrimental effects in females, and immunomodulation was identified as the primary mechanism.

Exercise has the guts: How physical activity may positively modulate gut microbiota in chronic and immune-based diseases

Limited animal and human research findings suggests that exercise might have a beneficial role for health gut. Cardiorespiratory fitness correlates with health-associated gut parameters such as taxonomic diversity and richness. Physical exercise may augment intestinal microbial diversity through several mechanisms including promotion of an anti-inflammatory state. Disease-associated microbial functions were linked to distinct taxa in previous studies of familial type 1 diabetes mellitus (T1D). An integrated multi-approach in the study of T1D, including physical exercise, is advocated. The present review explores how exercise might modulate gut microbiota and microbiome characteristics in chronic and immune-based diseases, given the demonstrated relationship between gut function and human health.

Fructose ingestion impairs expression of genes involved in skeletal muscle's adaptive response to aerobic exercise

Background

The inverse relationship between exercise capacity and its variation over time and both cardiovascular and all-cause mortality suggests the existence of an etiological nexus between cardiometabolic diseases and the molecular regulators of exercise capacity. Coordinated adaptive responses elicited by physical training enhance exercise performance and metabolic efficiency and possibly mediate the health benefits of physical exercise. In contrast, impaired expression of genes involved in mitochondrial biogenesis or protein turnover in skeletal muscle—key biological processes involved in adaptation to physical training—leads to insulin resistance and obesity. Ingestion of fructose has been shown to suppress the exercise-induced GLUT4 response in rat skeletal muscle. To evaluate in greater detail how fructose ingestion might blunt the benefits of physical training, we investigated the effects of fructose ingestion on exercise induction of genes that participate in regulation of mitochondrial biogenesis and protein turnover in rat’s skeletal muscle.

Methods

Eight-week-old Wistar rats were randomly assigned to sedentary (C), exercise (treadmill running)-only (E), fructose-only (F), and fructose + exercise (FE) groups and treated accordingly for 8 weeks. Blood and quadriceps femoris were collected for biochemistry, serum insulin, and gene expression analysis. Expression of genes involved in regulation of mitochondrial biogenesis and autophagy, GLUT4, and ubiquitin E3 ligases MuRF-1, and MAFbx/Atrogin-1 were assayed with quantitative real-time polymerase chain reaction.

Results

Aerobic training improved exercise capacity in both E and FE groups. A main effect of fructose ingestion on body weight and fasting serum triglyceride concentration was detected. Fructose ingestion impaired the expression of PGC-1α, FNDC5, NR4A3, GLUT4, Atg9, Lamp2, Ctsl, Murf-1, and MAFBx/Atrogin-1 in skeletal muscle of both sedentary and exercised animals while expression of Errα and Pparδ was impaired only in exercised rats.

Conclusions

Our results show that fructose ingestion impairs the expression of genes involved in biological processes relevant to exercise-induced remodeling of skeletal muscle. This might provide novel insight on how a dietary factor contributes to the genesis of disorders of glucose metabolism.

Why should people with type 1 diabetes exercise regularly?

Plethoric evidence reminds of the protective effects of exercise against a number of health risks, across all ages, in the general population. The benefits of exercise for individuals with type 2 diabetes are indisputable. An in-depth understanding of energy metabolism has reasonably entailed exercise as a cornerstone in the lifestyle of almost all subjects with type 1 diabetes. Nevertheless, individuals with type 1 diabetes often fail in accomplishing exercise guidelines and they are less active than their peer without diabetes. Two major obstacles are feared by people with type 1 diabetes who wish to exercise regularly: management of blood glucose control and hypoglycemia. Nowadays, strategies, including glucose monitoring technology and insulin pump therapy, have significantly contributed to the participation in regular physical activity, and even in competitive sports, for people with type 1 diabetes. Novel modalities of training, like different intensity, interspersed exercise, are as well promising. The beneficial potential of exercise in type 1 diabetes is multi-faceted, and it has to be fully exploited because it goes beyond the insulin-mimetic action, possibly through immunomodulation.

Active Subjects With Autoimmune Type 1 Diabetes Have Better Metabolic Profiles Than Sedentary Controls

Previous studies in humans with type 1 diabetes mellitus (T1D) and in nonobese diabetic mice have investigated the beneficial immunomodulatory potential of aerobic physical activity. Performing high volume of aerobic exercise may favorably regulate autoimmunity in diabetes. We tested whether increased physical activity is a self-sufficient positive factor in T1D subjects. During a 3-month observational period, active (six males; 40.5 ± 6.1 years; BMI: 24.5 ± 2.1) and sedentary (four males, three females; 35.9 ± 8.9 years; BMI: 25.7 ± 3.8) T1D individuals on insulin pump therapy were studied for metabolic, inflammatory, and autoimmune parameters. At baseline and at the end of a 3-month period, glycosylated hemoglobin (HbA1c), autoantibodies (anti-GAD, anti-ZnT8, anti-IA2, and ICA) and proinflammatory cytokines (IL-6 and TNF-α) were evaluated. During the third month of the period, physically active T1D patients showed a significant reduction in the average glucose levels (-9%, p = 0.025, by CGM) compared to the first month values, and even their hyperglycemic episodes (>180 mg/dl) diminished significantly (-24.2%, p = 0.032 vs. first month). Moreover, active T1D subjects exhibited an improved body composition with respect to sedentary controls. No significant changes were detected as to the autoimmune and inflammatory profiles. This study confirms the beneficial role of physical exercise associated with insulin pump therapy in order to improve metabolic control in individuals with T1D. These preliminary positive observations need to be challenged in a prolonged interventional follow-up.