Islet Regeneration During the Reversal of Autoimmune Diabetes in NOD Mice

Beyond Tuberculosis: The Surprising Immunological Benefits of the Bacillus Calmette-Guérin (BCG) Vaccine in Infectious, Auto-Immune, and Inflammatory Diseases

The Bacillus Calmette-Guérin (BCG) vaccine, best known for its role in preventing tuberculosis, has recently garnered attention for its broader immunomodulatory effects. By inducing trained immunity, BCG reprograms innate immune cells, enhancing their responses to various pathogens. This process, driven by epigenetic and metabolic reprogramming, suggests that BCG may have therapeutic potential far beyond tuberculosis. Emerging evidence points to its potential benefits in conditions such as autoimmune diseases, cancer, and viral infections. Furthermore, by modulating immune activity, BCG has been proposed to reduce chronic inflammation and promote immune tolerance. This review delves into the multifaceted role of BCG, highlighting its potential as a versatile therapeutic tool for managing a wide range of diseases.

Reduction of hyperglycemia in STZ-induced diabetic mice by prophylactic treatment with heat-killed Mycobacterium aurum: possible effects on glucose utilization, mitochondrial uncoupling, and oxidative stress in liver and skeletal muscle

Background

In addition to conventional treatment and modifications in physical activity and diet, alternative strategies have been investigated to manage, prevent, or delay diabetes in humans. In this regard, one strategy has relied on the immunomodulatory properties of mycobacteria, whereby Bacillus Calmette-Guerin, an attenuated live strain of Mycobacterium bovis, has been shown to improve glycemic control in patients with diabetes and to alleviate hyperglycemia in selected murine models of diabetes. A novel heat-killed (HK) whole-cell preparation of Mycobacterium aurum (M. aurum) is currently under development as a potential food supplement; nevertheless, its potential bioactivity remains largely unknown. Thus, the present study investigated the potential prophylactic anti-diabetic effects of HK M. aurum in streptozotocin (STZ)-induced diabetic mice.

Methods

Mice were divided into three groups: the STZ-induced diabetic group was injected with a single intraperitoneal high dose of STZ, the HK M. aurum-treated diabetic group was prophylactically treated with three doses of HK M. aurum 6 weeks before STZ injection, and the control non-diabetic group was given three intradermal injections of borate-buffered saline and an intraperitoneal injection of citrate buffer. Liver lactate dehydrogenase (LDH), uncoupling protein 2 (UCP2), and glucose transporter 2 (GLUT2) and skeletal muscle LDH, UCP3, and GLUT4 protein expression levels in different mouse groups were determined by Western blot.

Results

Our results indicated that HK M. aurum did not cause any significant changes in glycemic levels of normal non-diabetic mice. Prophylactic administration of three doses of HK M. aurum to diabetic mice resulted in a significant reduction in their blood glucose levels when compared to those in control diabetic mice. Prophylactic treatment of diabetic mice with HK M. aurum significantly restored their disturbed protein expression levels of liver UCP2 and LDH as well as of skeletal muscle UCP3. On the other hand, prophylactic treatment of diabetic mice with HK M. aurum had no significant effect on their liver GLUT2 and skeletal muscle GLUT4 and LDH protein expression levels.

Conclusions

Our findings provide the first evidence that HK M. aurum possesses a hyperglycemia-lowering capacity and might support its future use as a food supplement for the amelioration of diabetes.

The spleen assumes a major role in blood glucose regulation in type 1 diabetes patients treated with BCG

The Bacillus Calmette-Guérin (BCG) vaccine, which has been used for > 100 years to prevent tuberculosis, is well-established for bladder cancer treatment, and under study for neurological and autoimmune diseases. In patients with type 1 diabetes (T1D), BCG vaccinations have been shown in randomized clinical trials to gradually lower blood sugar to near normal levels. This effect appears to be driven by a BCG-induced shift in lymphoid cells' glucose metabolism from oxidative phosphorylation to aerobic glycolysis. The latter is a state of high glucose utilization that draws more glucose from the blood. Apart from blood, it is unknown whether BCG establishes residence in any organs and alters their glucose metabolism. In this two-year-long clinical trial in type 1 diabetics, we use positron emission tomography (PET) and x-ray computed tomography (CT) to map organs that increase their uptake of the glucose analogue 18F-fluorodeoxyglucose (18F-FDG) before versus after BCG vaccinations. We also injected BALB/c mice with BCG to test for the presence of BCG in various organs. Results from both studies point to the spleen as the dominant site for glucose uptake and BCG residence. The human spleen is significant because its 47% increase in 18F-FDG uptake by a large population of lymphocytes and monocytes might help to explain BCG's systemic lowering of blood glucose to near normal levels. Findings suggest that the spleen, triggered by BCG, assumes a critical role in systemic glucose regulation in the absence of a functional pancreas.

Chronic consumption of imbalance diets high in sucrose or fat induces abdominal obesity with different pattern of metabolic disturbances and lost in Langerhans cells population

AIM

Obesity is a worldwide health issue, associated with development of type 2 Diabetes Mellitus. The aim of this study is to analyze the effect of consumption of two hypercaloric diets on metabolic disturbance and beta cells damage.

MAIN METHODS

Male Wistar rats were subjected to twelve months consumption of three diets: a Control balanced diet (CTD, carbohydrates 58 %, proteins 29 %, lipids 13 %) and two hypercaloric diets, high in sucrose (HSD, carbohydrates 68 %, proteins 22 %, lipids 10 %) or high in fat (HFD, carbohydrates 31 %, proteins 14 %, lipids 55 %). Serum levels of glucose, triglycerides and free fatty acids were measured after zoometric parameters determination. Antioxidant enzymes activity and oxidative stress-marker were measured in pancreas tissue among histological analysis of Langerhans islets.

KEY FINDINGS

Although diets were hypercaloric, the amount of food consumed by rats decreased, resulting in an equal caloric consumption. The HSD induced hypertriglyceridemia and hyperglycemia with higher levels in free fatty acids (FFA, lipotoxicity); whereas HFD did not increased neither the triglycerides nor FFA, nevertheless the loss of islets' cell was larger. Both diets induced obesity with hyperglycemia and significant reduction in Langerhans islets size.

SIGNIFICANCE

Our results demonstrate that consumption of HSD induces more significant metabolic disturbances that HFD, although both generated pancreas damage; as well hypercaloric diet consumption is not indispensable to becoming obese; the chronic consumption of unbalanced diets (rich in carbohydrates or lipids) may lead to abdominal obesity with metabolic and functional disturbances, although the total amount of calories are similar.

Global research trends of diabetes remission: a bibliometric study

Background

Research on diabetes remission has garnered prominence in recent years. However, to date, no pertinent bibliometric study has been published. This study sought to elucidate the current landscape and pinpoint potential new research directions through a bibliometric analysis of diabetes remission.

Methods

We perused relevant articles on diabetes remission from January 1, 2000, to April 16, 2023, in the Web of Science. We utilized CiteSpace software and VOSviewer software to construct knowledge maps and undertake analysis of countries, institutional affiliations, author contributions, journals, and keywords. This analysis facilitated the identification of current research foci and forecasting future trends.

Results

A total of 970 English articles were procured, and the annual publication volume manifested a steady growth trend. Most of the articles originated from America (n=342, 35.26%), succeeded by China and England. Pertaining to institutions, the University of Newcastle in England proliferated the most articles (n=36, 3.71%). Taylor R authored the most articles (n=35, 3.61%), and his articles were also the most co-cited (n=1756 times). Obesity Surgery dominated in terms of published articles (n=81, 8.35%). "Bariatric surgery" was the most prevalently used keyword. The keyword-clustering map revealed that the research predominantly centered on diabetes remission, type 1 diabetes, bariatric surgery, and lifestyle interventions. The keyword emergence and keyword time-zone maps depicted hotspots and shifts in the domain of diabetes remission. Initially, the hotspots were primarily fundamental experiments probing the feasibilities and mechanisms of diabetes remission, such as transplantation. Over the course, the research trajectory transitioned from basic to clinical concerning diabetes remission through bariatric surgery, lifestyle interventions, and alternative strategies.

Conclusion

Over the preceding 20 years, the domain of diabetes remission has flourished globally. Bariatric surgery and lifestyle interventions bestow unique advantages for diabetes remission. Via the maps, the developmental milieu, research foci, and avant-garde trends in this domain are cogently portrayed, offering guidance for scholars.

Effects of Bacillus Calmette-Guérin on immunometabolism, microbiome and liver diseases⋆

Metabolic diseases have overtaken infectious diseases as the most serious public health issue and economic burden in most countries. Moreover, metabolic diseases increase the risk of having infectious diseases. The treatment of metabolic disease may require a long-term strategy of taking multiple medications, which can be costly and have side effects. Attempts to expand the therapeutic use of vaccination to prevent or treat metabolic diseases have attracted significant interest. A growing body of evidence indicates that Bacillus Calmette-Guérin (BCG) offers protection against non-infectious diseases. The non-specific effects of BCG occur likely due to the induction of trained immunity. In this regard, understanding how BCG influences the development of chronic metabolic health including liver diseases would be important. This review focuses on research on BCG, the constellation of disorders associated with metabolic health issues including liver diseases and diabetes as well as how BCG affects the gut microbiome, immunity, and metabolism.

Sarcoidosis rates in BCG-vaccinated and unvaccinated young adults: A natural experiment using Danish registers

OBJECTIVES

Sarcoidosis may have an infectious trigger, including Mycobacterium spp. The Bacille Calmette-Guérin (BCG) vaccine provides partial protection against tuberculosis and induces trained immunity. We examined the incidence rate (IR) of sarcoidosis in Danish individuals born during high BCG vaccine uptake (born before 1976) compared with individuals born during low BCG vaccine uptake (born in or after 1976).

METHODS

We performed a quasi-randomized registry-based incidence study using data from the Danish Civil Registration System and the Danish National Patient Registry between 1995 and 2016. We included individuals aged 25-35 years old and born between 1970 and 1981. Using Poisson regression models, we calculated the incidence rate ratio (IRR) of sarcoidosis in individuals born during low BCG vaccine uptake versus high BCG vaccine uptake, adjusting for age and calendar year (separately for men and women).

RESULTS

The IR of sarcoidosis was increased for individuals born during low BCG vaccine uptake compared with individuals born during high BCG vaccine uptake, which was largely attributed to men. The IRR of sarcoidosis for men born during low BCG vaccine uptake versus high BCG vaccine uptake was 1.22 (95% confidence interval [CI] 1.02-1.45). In women, the IRR was 1.08 (95% CI 0.88-1.31).

CONCLUSION

In this quasi-experimental study that minimizes confounding, the time period with high BCG vaccine uptake was associated with a lower incidence rate of sarcoidosis in men, with a similar effect seen in women that did not reach significance. Our findings support a potential protective effect of BCG vaccination against the development of sarcoidosis. Future interventional studies for high-risk individuals could be considered.

BCG Vaccination and the Risk of Type 1 Diabetes Mellitus: A Systematic Review and Meta-Analysis

(1) Background: Type 1 diabetes mellitus (T1D) is an autoimmune disease characterized by progressive and irreversible autoimmune destruction of pancreatic beta cell islets, resulting in absolute insulin deficiency. To date, several epidemiologic and observational studies have evaluated the possible impact of BCG vaccination on T1D development, but the results are controversial. To elucidate this issue, we aimed to conduct a systematic review and meta-analysis of published cohort studies in this field. (2) Methods: A systematic search was performed for relevant studies published up to 20 September 2022 using Pubmed/Medline, Embase, and Scopus. Cohort studies, containing original information about the association between T1D and BCG vaccination, were included for further analysis. Pooled estimates and 95% confidence intervals (CI) for the risk ratio of T1D in BCG-vaccinated individuals compared to unvaccinated ones were assessed using the fixed effect model. (3) Results: Out of 630 potentially relevant articles, five cohort studies met the inclusion criteria. The total population of all included studies was 864,582. The overall pooled risk ratio of T1D development in BCG vaccinated and unvaccinated individuals was found to be 1.018 (95% CI 0.908-1.141, I²: 0%). (4) Conclusions: Our study revealed no protective or facilitative effect of prior BCG vaccination in T1D development.

Engineering live attenuated vaccines: Old dogs learning new tricks

Autoimmune diseases such as rheumatoid arthritis and type 1 diabetes are increasingly common global problems. Concerns about increases in the prevalence of such diseases and the limited efficacy of conventional treatment regimens necessitates new therapies to address these challenges. Autoimmune disease severity and dysbiosis are interconnected. Although probiotics have been established as a therapy to rebalance the microbiome and suppress autoimmune symptoms, these microbes tend to lack a number of advantageous qualities found in non-commensal bacteria. Through attenuation and genetic manipulation, these non-commensal bacteria have been engineered into recombinant forms that offer malleable platforms capable of addressing the immune imbalances found in RA and T1D. Such bacteria have been engineered to express valuable gene products known to suppress autoimmunity such as anti-inflammatory cytokines, autoantigens, and enzymes synthesizing microbial metabolites. This review will highlight current and emerging trends in the field and discuss how they may be used to prevent and control autoimmune diseases.

Protective role of hesperidin against diabetes induced spleen damage: Mechanism associated with oxidative stress and inflammation

Diabetes mellitus is a metabolic disease affecting various organs, including the spleen and is characterized by chronic hyperglycemia. Oxidative and inflammatory stress are key mediators in the development of spleen damage caused by diabetes. This study aimed to examine the splenoprotective effect of hesperidin and the mechanisms underlying its capacity to reduce oxidative stress and inflammation-mediated spleen damage in diabetes. The diabetic rats used in this study were induced with a 65 mg per kg body weight of streptozotocin. This was followed by 4 weeks of continuous daily dosage of hesperidin treatment at 100 mg/kg body weight. The results showed that hesperidin improved spleen weight and histopathological alterations in the diabetic rats. The hesperidin-treated diabetic group showed a marked induction of SOD and GPx enzymes and moderated malondialdehyde level. This was in addition to an obvious decrease in the levels of TNF-α and NF-ᴋB in the diabetic rat spleen. Through a remarkable upregulation in Bcl-xL and downregulation in Bax and cleaved caspase-3 proteins, hesperidin supplementation rescued splenic cell apoptosis in the diabetic rats. These findings demonstrate the effectiveness of hesperidin in helping regulate Bcl-2 family proteins and inhibiting the oxidative stress and inflammatory status of hyperglycemia-mediated spleen apoptosis. PRACTICAL APPLICATIONS: Diabetes-related spleen damage increases immune dysfunction, which often results in the heightened risks of infection, morbidity and mortality in diabetic patients. In this work, hesperidin was used in the treatment of rats with diabetes-induced splenic damage. The results were highly encouraging with hesperidin consistently presenting beneficial antioxidant and anti-inflammatory qualities and splenoprotective effect. Research outcomes support the notion that hesperidin treatment could be considered a good strategy for the prevention of diabetic complications in the spleen.

Whey protein and xylitol complex alleviate type 2 diabetes in C57BL/6 mice by regulating the intestinal microbiota

Type 2 diabetes (T2D) is a metabolic disorder that has become a major threat to public health. Epidemiological and experimental studies have suggested that whey protein isolate (WPI) and xylitol (XY) play an important role on T2D. This manuscript hypothesizes the supplementation of whey protein and xylitol complex (WXY) has the hypoglycemic and hyperlipidemia effect of T2D mice induced by the conjoint action of a high-fat diet and streptozotocin (STZ) by modulating of intestinal microbiota. The mice with diabetes displayed higher levels of fasting blood glucose (FBG), insulin, glycosylated hemoglobin, total triglycerides, total cholesterol, aspartate aminotransferase, alanine aminotransferase and other serum parameters than the normal mice. Treatment with WXY for 6 weeks significantly modulated the levels of FBG and insulin, improved insulin sensitivity, pancreas impairment and liver function in T2D mice, and the effect was better than that observed with WPI and XY groups. Moreover, supplementation with WXY significantly changed the diversity and composition of the intestinal microbiota in T2D mice and restored the intestinal bacteria associated with T2D (Firmicutes, Bacteroidetes, and Lactobacillus). This may be a potential mechanism for alleviating T2D symptoms. Spearman correlation analysis showed that the relative abundances of specific genera (Turicibacter, Lachnospiraceae_NK4A136_group, Lactobacillus, Candidatus_Saccharimonas, Faecalibaculum and Coriobacteriaceae_UCG-002) were correlated with the levels of blood glucose and serum parameters. Therefore, WXY may be considered a promising dietary supplement for T2D treatment in the future.

Trained Immunity Contribution to Autoimmune and Inflammatory Disorders

A dysregulated immune response toward self-antigens characterizes autoimmune and autoinflammatory (AIF) disorders. Autoantibodies or autoreactive T cells contribute to autoimmune diseases, while autoinflammation results from a hyper-functional innate immune system. Aside from their differences, many studies suggest that monocytes and macrophages (Mo/Ma) significantly contribute to the development of both types of disease. Mo/Ma are innate immune cells that promote an immune-modulatory, pro-inflammatory, or repair response depending on the microenvironment. However, understanding the contribution of these cells to different immune disorders has been difficult due to their high functional and phenotypic plasticity. Several factors can influence the function of Mo/Ma under the landscape of autoimmune/autoinflammatory diseases, such as genetic predisposition, epigenetic changes, or infections. For instance, some vaccines and microorganisms can induce epigenetic changes in Mo/Ma, modifying their functional responses. This phenomenon is known as trained immunity. Trained immunity can be mediated by Mo/Ma and NK cells independently of T and B cell function. It is defined as the altered innate immune response to the same or different microorganisms during a second encounter. The improvement in cell function is related to epigenetic and metabolic changes that modify gene expression. Although the benefits of immune training have been highlighted in a vaccination context, the effects of this type of immune response on autoimmunity and chronic inflammation still remain controversial. Induction of trained immunity reprograms cellular metabolism in hematopoietic stem cells (HSCs), transmitting a memory-like phenotype to the cells. Thus, trained Mo/Ma derived from HSCs typically present a metabolic shift toward glycolysis, which leads to the modification of the chromatin architecture. During trained immunity, the epigenetic changes facilitate the specific gene expression after secondary challenge with other stimuli. Consequently, the enhanced pro-inflammatory response could contribute to developing or maintaining autoimmune/autoinflammatory diseases. However, the prediction of the outcome is not simple, and other studies propose that trained immunity can induce a beneficial response both in AIF and autoimmune conditions by inducing anti-inflammatory responses. This article describes the metabolic and epigenetic mechanisms involved in trained immunity that affect Mo/Ma, contraposing the controversial evidence on how it may impact autoimmune/autoinflammation conditions.

The Clinical Characteristics and Gene Mutations of Maturity-Onset Diabetes of the Young Type 5 in Sixty-One Patients

AIMS

Maturity-onset diabetes of the young type 5 (MODY5), a rare disease, is very easy to be misdiagnosed as type 2 diabetes. To get better understanding of the disease, we analyzed the clinical characteristics and gene mutations of MODY5.

METHODS

PubMed, Cochrane, the China National Knowledge Infrastructure, and Wanfang were searched with the following search terms: "MODY5" OR "HNF1B maturity-onset diabetes of the young" OR "maturity-onset diabetes of the young type 5" OR "renal cysts and diabetes syndrome". Clinical characteristics and gene mutations of MODY5 were analyzed. The demography, clinical characteristics, and blood indicators of patients were described utilizing simple summary statistics. Variables were analyzed by t-test, Wilcoxon signed rank test, and Fisher exact test. Spearman's correlation analysis was used for bi-variate analysis. All tests were two-sided, and a p-value < 0.05 was considered statistically significant. Statistical analysis was performed using the Statistical Package for the Social Sciences version 26 for Windows (SPSS).

RESULTS

A total of 48 literatures were included in this study, including 61 eligible patients and 4 different mutations. Of the 39 patients with available body weight index, 15 (38.46%) were underweight, 21 (53.85%) were normal weight and 3 (7.69%) were overweight or obese. Of the 38 patients with available family history, 25 (65.79%) reported a family history of diabetes. Of the 34 patients with available age of diabetes diagnosis, the median age of diabetes diagnosis was 16.00 years old and 88.24% (30/34) of patients were under 25 years old when they were first diagnosed with diabetes. Renal cysts were presented in 72.41%, hypomagnesemia in 91.67%, and pancreatic dysplasia in 71.88% of the patients. Patients with hepatocyte nuclear factor 1B (HNF1B) deletion had lower serum magnesium, serum creatinine, and higher eGFR than patients with other gene mutations, and the difference was statistically significant.

CONCLUSIONS

The young onset of diabetes with low or normal BMI, renal cysts, hypomagnesemia, and pancreatic dysplasia should be recommended to genetic testing in order to differentiate MODY5 from other types of diabetes earlier.

The Role of Pediatric BCG Vaccine in Type 1 Diabetes Onset

INTRODUCTION

Bacille Calmette-Guérin (BCG) vaccination has shown promising therapeutic effects for type 1 diabetes (T1D). According to recent studies, immunometabolism modification and regulation of T lymphocytes constitute the proposed mechanisms by which BCG vaccination may delay T1D onset. Clinical trial evidence from Turkey supports that two to three doses of the BCG vaccine in childhood, with the first dose administered in the first year of life, may prevent T1D. In the same study, one or zero vaccinations appeared to have no effect in T1D onset prevention. In Greece, the BCG vaccine was administered in a single dose at the age of 9 years in elementary school. BCG vaccination was not performed on a mandatory basis, creating one BCG vaccinated and one non-vaccinated population. The aim of our study was to investigate the possible effect of a single dose of BCG vaccine, at the age of 9 years, on the time of T1D onset, in a population of BCG vaccinated and non-vaccinated patients with diagnosed T1D.

METHODS

To test this hypothesis, a survey through the Pan-Hellenic Federation of People with Diabetes (PFPD) was performed. In this observational, retrospective study, participating patients provided information regarding age, gender, time of diagnosis, and BCG vaccination status. Patients diagnosed with T1D before the age of 9 years were excluded from the analysis.

RESULTS

The final sample included 196 patients (73 male and 123 female) with a mean age of 42.2 ± 14.3 years and a mean duration of diabetes of 16.8 ± 12.9 years. Mean age of T1D diagnosis in the BCG vaccinated group was 24.0 ± 19.0 years, while the mean age of T1D diagnosis in the BCG non-vaccinated group was 21.5 ± 14.3 years (p = 0.03). No interaction was found between gender and the age of diagnosis for BCG vaccinated and unvaccinated patients (p = 0.86).

CONCLUSION

The results of our study suggest that a single dose of BCG vaccine, performed at the age of 9 years, may delay the onset of T1D by 2.5 years. Additional studies of children receiving multiple doses of BCG should be conducted to possibly prove prolongation of the disease-free interval.

TAZ inhibits acinar cell differentiation but promotes immature ductal cell proliferation in adult mouse salivary glands

There are currently no treatments for salivary gland diseases, making it vital to understand signaling mechanisms operating in acinar and ductal cells so as to develop regenerative therapies. To date, little work has focused on elucidating the signaling cascades controlling the differentiation of these cell types in adult mammals. To analyze the function of the Hippo-TAZ/YAP1 pathway in adult mouse salivary glands, we generated adMOB1DKO mice in which both MOB1A and MOB1B were TAM-inducibly deleted when the animals were adults. Three weeks after TAM treatment, adMOB1DKO mice exhibited smaller submandibular glands (SMGs) than controls with a decreased number of acinar cells and an increased number of immature dysplastic ductal cells. The mutants suffered from reduced saliva production accompanied by mild inflammatory cell infiltration and fibrosis in SMGs, similar to the Sjogren's syndrome. MOB1-deficient acinar cells showed normal proliferation and apoptosis but decreased differentiation, leading to an increase in acinar/ductal bilineage progenitor cells. These changes were TAZ-dependent but YAP1-independent. Biochemically, MOB1-deficient salivary epithelial cells showed activation of the TAZ/YAP1 and β-catenin in ductal cells, but reduced SOX2 and SOX10 expression in acinar cells. Thus, Hippo-TAZ signaling is critical for proper ductal and acinar cell differentiation and function in adult mice.

Programmed cell death in stem cell-based therapy: Mechanisms and clinical applications

Stem cell-based therapy raises hopes for a better approach to promoting tissue repair and functional recovery. However, transplanted stem cells show a high death percentage, creating challenges to successful transplantation and prognosis. Thus, it is necessary to investigate the mechanisms underlying stem cell death, such as apoptotic cascade activation, excessive autophagy, inflammatory response, reactive oxygen species, excitotoxicity, and ischemia/hypoxia. Targeting the molecular pathways involved may be an efficient strategy to enhance stem cell viability and maximize transplantation success. Notably, a more complex network of cell death receives more attention than one crucial pathway in determining stem cell fate, highlighting the challenges in exploring mechanisms and therapeutic targets. In this review, we focus on programmed cell death in transplanted stem cells. We also discuss some promising strategies and challenges in promoting survival for further study.

Efficacy of mesenchymal stem cell therapy on glucose levels in type 2 diabetes mellitus: A systematic review and meta-analysis

AIMS/INTRODUCTION

In recent years, mesenchymal cellular therapies have received much attention in the treatment of diabetes. In this meta-analysis, we aimed to evaluate the efficacy of mesenchymal stem cell therapy in type 2 diabetes mellitus patients.

MATERIALS AND METHODS

A comprehensive literature search was carried out using PubMed, Scopus, Web of Science and Central databases. A total of 1,721 articles were identified, from which nine full-text clinical trials were qualified to enter the current meta-analysis. The assessment groups included patients with type 2 diabetes, and levels of C-peptide, glycosylated hemoglobin and insulin dose were analyzed before and after mesenchymal stem cell infusion. Data analysis was carried out in Stata version 11, and the Jadad Score Scale was applied for quality assessment.

RESULTS

Changes in levels of C-peptide after mesenchymal stem cell therapy were: standardized mean difference 0.20, 95% confidence interval -0.61 to 1.00, glycosylated hemoglobin levels were: standardized mean difference -1.45, 95% confidence interval -2.10 to -0.79 and insulin dose were: standardized mean difference -1.40, 95% confidence interval -2.88 to 0.09.

CONCLUSIONS

This meta-analysis of prospective studies showed associations between mesenchymal stem cell therapy and control of glucose level in patients with type 2 diabetes.

Advances in Pancreatic Islet Transplantation Sites for the Treatment of Diabetes

Diabetes is a complex disease that affects over 400 million people worldwide. The life-long insulin injections and continuous blood glucose monitoring required in type 1 diabetes (T1D) represent a tremendous clinical and economic burdens that urges the need for a medical solution. Pancreatic islet transplantation holds great promise in the treatment of T1D; however, the difficulty in regulating post-transplantation immune reactions to avoid both allogenic and autoimmune graft rejection represent a bottleneck in the field of islet transplantation. Cell replacement strategies have been performed in hepatic, intramuscular, omentum, and subcutaneous sites, and have been performed in both animal models and human patients. However more optimal transplantation sites and methods of improving islet graft survival are needed to successfully translate these studies to a clinical relevant therapy. In this review, we summarize the current progress in the field as well as methods and sites of islet transplantation, including stem cell-derived functional human islets. We also discuss the contribution of immune cells, vessel formation, extracellular matrix, and nutritional supply on islet graft survival. Developing new transplantation sites with emerging technologies to improve islet graft survival and simplify immune regulation will greatly benefit the future success of islet cell therapy in the treatment of diabetes.

BCG immunomodulation: From the 'hygiene hypothesis' to COVID-19

The century-old tuberculosis vaccine BCG has been the focus of renewed interest due to its well-documented ability to protect against various non-TB pathogens. Much of these broad spectrum protective effects are attributed to trained immunity, the epigenetic and metabolic reprogramming of innate immune cells. As BCG vaccine is safe, cheap, widely available, amendable to use as a recombinant vector, and immunogenic, it has immense potential for use as an immunotherapeutic agent for various conditions including autoimmune, allergic, neurodegenerative, and neoplastic diseases as well as a preventive measure against infectious agents. Of particular interest is the use of BCG vaccination to counteract the increasing prevalence of autoimmune and allergic conditions in industrialized countries attributable to reduced infectious burden as described by the 'hygiene hypothesis.' Furthermore, BCG vaccination has been proposed as a potential therapy to mitigate spread and disease burden of COVID-19 as a bridge to development of a specific vaccine and recombinant BCG expression vectors may prove useful for the introduction of SARS-CoV-2 antigens (rBCG-SARS-CoV-2) to induce long-term immunity. Understanding the immunomodulatory effects of BCG vaccine in these disease contexts is therefore critical. To that end, we review here BCG-induced immunomodulation focusing specifically on BCG-induced trained immunity and how it relates to the 'hygiene hypothesis' and COVID-19.

Trained immunity as a novel approach against COVID-19 with a focus on Bacillus Calmette-Guérin vaccine: mechanisms, challenges and perspectives

COVID-19 is a severe health problem in many countries and has altered day-to-day life in the whole world. This infection is caused by the SARS-CoV-2 virus, and depending on age, sex and health status of the patient, it can present with variety of clinical symptoms such as mild infection, a very severe form or even asymptomatic course of the disease. Similarly to other viruses, innate immune response plays a vital role in protection against COVID-19. However, dysregulation of innate immunity could have a significant influence on the severity of the disease. Despite various efforts, there is no effective vaccine against the disease so far. Recent data have demonstrated that the Bacillus Calmette-Guérin (BCG) vaccine could reduce disease severity and the burden of several infectious diseases in addition to targeting its primary focus tuberculosis. There is growing evidence for the concept of beneficial non-specific boosting of immune responses by BCG or other microbial compounds termed trained immunity, which may protect against COVID-19. In this manuscript, we review data on how the development of innate immune memory due to microbial compounds specifically BCG can result in protection against SARS-CoV-2 infection. We also discuss possible mechanisms, challenges and perspectives of using innate immunity as an approach to reduce COVID-19 severity.

Anti-diabetic effect of a novel oligosaccharide isolated from Rosa canina via modulation of DNA methylation in Streptozotocin-diabetic rats

BACKGROUND

Diabetes mellitus (DM) is a well-known clinical entity with various late complications. There is a surge of research aiming to use the medical herb in the management of DM.

OBJECTIVE

This study aimed to investigate whether the alleviation of DM by an isolated compound from Rosa canina is mediated by DNA methylation in STZ-diabetic rats.

METHODS

Sixty adult Wistar male rats were classified into control, diabetic and treatment groups. Rats were treated with STZ (40 mg/kg), metformin (500 mg/kg), and oligosaccharide fraction (OF; 10, 20 and 30 mg/kg) isolated from Rosa canina. DNA was extracted from the blood and pancreas to determine DNA methylation using the Global DNA Methylation kit. The expressions of DNA methyltransferases (Dnmts), PDX1, Ins1, GCK and PTP1B2 were determined by using qRT-PCR.

RESULTS

The significant blood glucose-lowering potential of OF was associated with a reduced level of global DNA methylation (p < 0.05). The expression levels of Dnmts 1 and 3α increased in the pancreas and blood from diabetic rats compared to control group which declined by OF treatment (p < 0.05). Paradoxically, the expression of Dnmt 3β augmented in the pancreas and blood of OF group compared to diabetic ones (p < 0.05). Besides, the expressions of Pdx1, PTP1B2, Ins1 and GCK increased in OF-treated rats compared to diabetic groups.

CONCLUSION

Results revealed that DNA methylation plays a causal role in the effectiveness of the isolated OF. Furthermore, the possible regenerative potential of oligosaccharide in diabetic rats may have contributed to the modulation of DNA methylation.

Benefits of BCG-induced metabolic switch from oxidative phosphorylation to aerobic glycolysis in autoimmune and nervous system diseases

The most commonly used vaccine worldwide, bacillus Calmette-Guerin (BCG), appears to have the ability to restore blood sugar control in humans with early-onset but long-duration type 1 diabetes when a repeat vaccination strategy is used. This is a process that may be driven by a metabolic switch from overactive oxidative phosphorylation to accelerated aerobic glycolysis and a reset of the immune system. BCG is a live, attenuated strain of Mycobacteria bovis, a cousin of M. tuberculosis. Humans and Mycobacteria, which are found in the environment and in warm-blooded hosts, share a long coevolutionary history. In recent times, humans have had fewer exposures to these and other microorganisms that historically helped shape the immune response. By 're-introducing' an attenuated form of Mycobacteria via BCG vaccination, humans might benefit from an immunological perspective, a concept supported by a growing body of data in autoimmunity and robust data on the nonspecific immune effects of BCG related to protection from diverse infections and early mortality. New findings of immune and metabolic defects in type 1 diabetes that can be corrected with repeat BCG vaccination suggest that this therapeutic strategy may be applicable in other diseases with inadequate aerobic glycolysis, including Parkinson's disease, dementia, depression and other disorders affecting the nervous system.

Comparative Study of Two Different Islet Transplantation Sites in Mice: Hepatic Sinus Tract vs Splenic Parenchyma

Although 90% of clinical islet transplantations are performed via the portal vein approach, it is still far from the ideal transplant site. Alternative islet transplant sites are promising to reduce the islet dose required to reverse hyperglycemia, thereby improving the efficiency of islet transplantation. The aim of this study was to compare the differences in survival and metabolic function of islet grafts transplanted into the hepatic sinus tract (HST) and the splenic parenchyma (SP). Approximately 300 syngeneic mouse islets were transplanted into the HST (n = 6) and the SP (n = 6) of recipient diabetic mice, respectively. After transplantation, the glycemic control, glucose tolerance, and morphology of islet grafts were evaluated and compared in each group. The nonfasting blood glucose of the two groups of mice receiving islet transplantation gradually decreased to the normal range and sustained for more than 100 d. There is no significant difference in the time required to restore normoglycemia (P > 0.05). The results of the glucose tolerance test showed that the SP group presented a smaller area under the curve than the HST group (P < 0.05). Histopathological results showed that islet grafts in the HST and the SP were characterized with normal islet morphology and robust insulin production. Compared with the HST, islet transplantation in the SP presents better blood glucose regulation, although there is no significant difference in the time required to restore normoglycemia.

Functional β-Cell Differentiation of Small-Tail Han Sheep Pancreatic Mesenchymal Stem Cells and the Therapeutic Potential in Type 1 Diabetic Mice

OBJECTIVES

This study aims to investigate the characteristics of sheep pancreatic mesenchymal stem cells (PSCs) and therapeutic potential of differentiated β-like cells in streptozotocin-induced diabetic mice.

METHODS

Pancreatic mesenchymal stem cells were isolated from 3- to 4-month-old sheep embryos, and their biological characteristics were explored. The function and therapeutic potential of differentiated β-like insulin-producing cells were also investigated in vitro and in vivo. Differentiated cells were identified through dithizone staining and immunofluorescence staining. Insulin secretion was analyzed using an enzyme-linked immunosorbent assay kit. The preliminary therapeutic potential of induced β-like cells in diabetic mice was detected by blood glucose and body weight.

RESULTS

Primary PSCs were isolated and subcultured up to passage 36. Immunofluorescence staining presented PSC-expressed important markers such as Pdx1, Nkx6-1, Ngn3, and Nestin. Primary PSCs could be induced into functional pancreatic β-like islet cells with a 3-step protocol. The induced β-like islet cells could ameliorate blood glucose in diabetic mice.

CONCLUSIONS

The method proposed for generating pancreatic islet β cells provided a preliminary phenotypic investigation of induced cell treatment in diabetic mice, and also laid a foundation in the identification of pharmaceutical targets to treat insulin-dependent diabetes.

Selective Targeting of TNF Receptors as a Novel Therapeutic Approach

Tumor necrosis factor (TNF) is a central regulator of immunity. Due to its dominant pro-inflammatory effects, drugs that neutralize TNF were developed and are clinically used to treat inflammatory and autoimmune diseases, such as rheumatoid arthritis, inflammatory bowel disease and psoriasis. However, despite their clinical success the use of anti-TNF drugs is limited, in part due to unwanted, severe side effects and in some diseases its use even is contraindicative. With gaining knowledge about the signaling mechanisms of TNF and the differential role of the two TNF receptors (TNFR), alternative therapeutic concepts based on receptor selective intervention have led to the development of novel protein therapeutics targeting TNFR1 with antagonists and TNFR2 with agonists. These antibodies and bio-engineered ligands are currently in preclinical and early clinical stages of development. Preclinical data obtained in different disease models show that selective targeting of TNFRs has therapeutic potential and may be superior to global TNF blockade in several disease indications.

BCG as a Case Study for Precision Vaccine Development: Lessons From Vaccine Heterogeneity, Trained Immunity, and Immune Ontogeny

Vaccines have been traditionally developed with the presumption that they exert identical immunogenicity regardless of target population and that they provide protection solely against their target pathogen. However, it is increasingly appreciated that vaccines can have off-target effects and that vaccine immunogenicity can vary substantially with demographic factors such as age and sex. Bacille Calmette-Guérin (BCG), the live attenuated Mycobacterium bovis vaccine against tuberculosis (TB), represents a key example of these concepts. BCG vaccines are manufactured under different conditions across the globe generating divergent formulations. Epidemiologic studies have linked early life immunization with certain BCG formulations to an unanticipated reduction (∼50%) in all-cause mortality, especially in low birthweight males, greatly exceeding that attributable to TB prevention. This mortality benefit has been related to prevention of sepsis and respiratory infections suggesting that BCG induces "heterologous" protection against unrelated pathogens. Proposed mechanisms for heterologous protection include vaccine-induced immunometabolic shifts, epigenetic reprogramming of innate cell populations, and modulation of hematopoietic stem cell progenitors resulting in altered responses to subsequent stimuli, a phenomenon termed "trained immunity." In addition to genetic differences, licensed BCG formulations differ markedly in content of viable mycobacteria key for innate immune activation, potentially contributing to differences in the ability of these diverse formulations to induce TB-specific and heterologous protection. BCG immunomodulatory properties have also sparked interest in its potential use to prevent or alleviate autoimmune and inflammatory diseases, including type 1 diabetes mellitus and multiple sclerosis. BCG can also serve as a model: nanoparticle vaccine formulations incorporating Toll-like receptor 8 agonists can mimic some of BCG's innate immune activation, suggesting that aspects of BCG's effects can be induced with non-replicating stimuli. Overall, BCG represents a paradigm for precision vaccinology, lessons from which will help inform next generation vaccines.

BCG-Induced Cross-Protection and Development of Trained Immunity: Implication for Vaccine Design

The Bacillus Calmette-Guérin (BCG) is a live attenuated tuberculosis vaccine that has the ability to induce non-specific cross-protection against pathogens that might be unrelated to the target disease. Vaccination with BCG reduces mortality in newborns and induces an improved innate immune response against microorganisms other than Mycobacterium tuberculosis, such as Candida albicans and Staphylococcus aureus. Innate immune cells, including monocytes and natural killer (NK) cells, contribute to this non-specific immune protection in a way that is independent of memory T or B cells. This phenomenon associated with a memory-like response in innate immune cells is known as "trained immunity." Epigenetic reprogramming through histone modification in the regulatory elements of particular genes has been reported as one of the mechanisms associated with the induction of trained immunity in both, humans and mice. Indeed, it has been shown that BCG vaccination induces changes in the methylation pattern of histones associated with specific genes in circulating monocytes leading to a "trained" state. Importantly, these modifications can lead to the expression and/or repression of genes that are related to increased protection against secondary infections after vaccination, with improved pathogen recognition and faster inflammatory responses. In this review, we discuss BCG-induced cross-protection and acquisition of trained immunity and potential heterologous effects of recombinant BCG vaccines.

Direct differentiation of bone marrow mononucleated cells into insulin producing cells using pancreatic β-cell-derived components

Transplantation of stem cell-derived insulin producing cells (IPCs) has been proposed as an alternative to islet transplantation for the treatment of diabetes mellitus. However, current IPC differentiation protocols are focused on generating functional cells from the pluripotent stem cells and tend to rely on multistep, long-term exposure to various exogenous factors. In this study, we addressed the observation that under stress, pancreatic β-cells release essential components that direct the differentiation of the bone marrow nucleated cells (BMNCs) into IPCs. Without any supplementation with known differentiation-inducing factors, IPCs can be generated from BMNCs by in vitro priming for 6 days with conditioned media (CM) from the β-cells. In vitro primed BMNCs expressed the β-cell-specific transcription factors, as well as insulin, and improved hyperglycemia and glucose intolerance after transplantation into the streptozotocin-induced diabetic mice. Furthermore, we have found that components of the CM which trigger the differentiation were enclosed by or integrated into micro particles (MPs), rather than being secreted as soluble factors. Identification of these differentiation-directing factors might enable us to develop novel technologies required for the production of clinically applicable IPCs.

Identification and characterization of splenic adherent cells forming densely-packed colonies

It is thought that the spleen contains stem cells that differentiate into somatic cells other than immune cells. We investigated the presence of these hypothetical splenic cells with stem cell characteristics and identified adherent cells forming densely-packed colonies (Splenic Adherent Colony-forming Cell; SACC) in the spleen. Splenic Adherent Colony-forming Cell was positive for alkaline phosphatase staining and stage-specific embryonic antigen (SSEA)-1 antigen. However, the self-renewal properties of SACCs were limited because they stopped cell proliferation once colonies visible to the naked eye were formed. Gene expression analyses by semi-quantitative RT-PCR revealed the significant expression of c-Myc and Klf4, whereas faint or no expression was evident for Nanog, Oct3/4, and Sox2. Global expression analyses by DNA microarray and subsequent gene ontology analyses revealed that the expression levels of genes related to the immune system were significantly lower in SACCs than in control splenic cells. In contrast, genes unrelated to the immune system, such as those involved in cell adhesion and axon guidance, were relatively highly expressed in SACCs compared with control splenic cells. Taken together, we identified a novel cell type residing in the spleen that is different from the hypothetical splenic stem cell, but which bears some, but not all, characteristics that represent an undifferentiated state.

Regenerative and Transplantation Medicine: Cellular Therapy Using Adipose Tissue-Derived Mesenchymal Stromal Cells for Type 1 Diabetes Mellitus

Type 1 diabetes mellitus (T1DM) is caused by the autoimmune targeting of pancreatic β-cells, and, in the advanced stage, severe hypoinsulinemia due to islet destruction. In patients with T1DM, continuous exogenous insulin therapy cannot be avoided. However, an insufficient dose of insulin easily induces extreme hyperglycemia or diabetic ketoacidosis, and intensive insulin therapy may cause hypoglycemic symptoms including hypoglycemic shock. While these insulin therapies are efficacious in most patients, some additional therapies are warranted to support the control of blood glucose levels and reduce the risk of hypoglycemia in patients who respond poorly despite receiving appropriate treatment. There has been a recent gain in the popularity of cellular therapies using mesenchymal stromal cells (MSCs) in various clinical fields, owing to their multipotentiality, capacity for self-renewal, and regenerative and immunomodulatory potential. In particular, adipose tissue-derived MSCs (ADMSCs) have become a focus in the clinical setting due to the abundance and easy isolation of these cells. In this review, we outline the possible therapeutic benefits of ADMSC for the treatment of T1DM.

BCG Therapy for Type 1 Diabetes: Restoration of Balanced Immunity and Metabolism

The bacillus Calmette-Guerin (BCG) vaccine is a microorganism developed as a vaccine for tuberculosis 100 years ago and used as therapy for bladder cancer 40 years ago. More recently, BCG has shown therapeutic promise for type 1 diabetes (T1D) and several other autoimmune diseases. In T1D, BCG restored blood sugars to near normal, even in patients with advanced disease of >20 years duration. This clinically important effect may be driven by resetting of the immune system and the shifting of glucose metabolism from overactive oxidative phosphorylation, a state of minimal sugar utilization, to aerobic glycolysis, a state of high glucose utilization, for energy production. The mechanistic findings support the Hygiene Hypothesis and reveal the immune and metabolic synergy of mycobacterial reintroduction in modern humans.

Bridging the gap between vaccination with Bacille Calmette-Guérin (BCG) and immunological tolerance: the cases of type 1 diabetes and multiple sclerosis

At the end of past century, when the prevailing view was that treatment of autoimmunity required immune suppression, experimental evidence suggested an approach of immune-stimulation such as with the BCG vaccine in type 1 diabetes (T1D) and multiple sclerosis (MS). Translating these basic studies into clinical trials, we showed the following: BCG harnessed the immune system to 'permanently' lower blood sugar, even in advanced T1D; BCG appeared to delay the disease progression in early MS; the effects were long-lasting (years after vaccination) in both diseases. The recently demonstrated capacity of BCG to boost glycolysis may explain both the improvement of metabolic indexes in T1D, and the more efficient generation of inducible regulatory T cells, which counteract the autoimmune attack and foster repair mechanisms.

Current Status of Stem Cell Treatment for Type I Diabetes Mellitus

BACKGROUND

Diabetes mellitus is a major health concern in current scenario which has been found to affect people of almost all ages. The disease has huge impact on global health; therefore, alternate methods apart from insulin injection are being explored to cure diabetes. Therefore, this review mainly focuses on the current status and therapeutic potential of stem cells mainly mesenchymal stem cells (MSCs) for Type 1 diabetes mellitus in preclinical animal models as well as humans.

METHODS

Current treatment for Type 1 diabetes mellitus mainly includes use of insulin which has its own limitations and also the underlying mechanism of diseases is still not explored. Therefore, alternate methods to cure diabetes are being explored. Stem cells are being investigated as an alternative therapy for treatment of various diseases including diabetes. Few preclinical studies have also been conducted using undifferentiated MSCs as well as in vitro MSCs differentiated into β islet cells.

RESULTS

These stem cell transplant studies have highlighted the benefits of MSCs, which have shown promising results. Few human trials using stem cells have also affirmed the potential of these cells in alleviating the symptoms.

CONCLUSION

Stem cell transplantation may prove to be a safe and effective treatment for patients with Type 1 diabetes mellitus.

Long-term reduction in hyperglycemia in advanced type 1 diabetes: the value of induced aerobic glycolysis with BCG vaccinations

Mycobacterium are among the oldest co-evolutionary partners of humans. The attenuated Mycobacterium bovis Bacillus Calmette Guérin (BCG) strain has been administered globally for 100 years as a vaccine against tuberculosis. BCG also shows promise as treatment for numerous inflammatory and autoimmune diseases. Here, we report on a randomized 8-year long prospective examination of type 1 diabetic subjects with long-term disease who received two doses of the BCG vaccine. After year 3, BCG lowered hemoglobin A1c to near normal levels for the next 5 years. The BCG impact on blood sugars appeared to be driven by a novel systemic and blood sugar lowering mechanism in diabetes. We observe a systemic shift in glucose metabolism from oxidative phosphorylation to aerobic glycolysis, a state of high glucose utilization. Confirmation is gained by metabolomics, mRNAseq, and functional assays of cellular glucose uptake after BCG vaccinations. To prove BCG could induce a systemic change to promote accelerated glucose utilization and impact blood sugars, murine data demonstrated reduced blood sugars and aerobic induction in non-autoimmune mice made chemically diabetic. BCG via epigenetics also resets six central T-regulatory genes for genetic re-programming of tolerance. These findings set the stage for further testing of a known safe vaccine therapy for improved blood sugar control through changes in metabolism and durability with epigenetic changes even in advanced Type 1 diabetes.

In patients with long-term type 1 diabetes, the tuberculosis vaccine BCG lowers blood sugar levels to near-normal after three years. Denise Faustman and her team from Massachusetts General Hospital and Harvard Medical School investigated a cohort of type 1 diabetics that received two doses of BCG before being monitored over eight years. After three years, vaccine-treated patients lowered their HbA1c levels—a diabetes biomarker reflecting average blood sugar over 8–12 weeks—by over 10%. This reduction increased to 18% in the fourth year, after which HbA1c levels remained low up to the final year of monitoring. The researchers report that the BCG vaccine appeared to reset diabetes-implicated parts of the immune system and, through a novel mechanism, shift glucose metabolism to lower blood sugar to healthy levels. Future studies will further classify BCG’s benefits in diabetes.

The Spleen as an Optimal Site for Islet Transplantation and a Source of Mesenchymal Stem Cells

This review demonstrates the unique potential of the spleen as an optimal site for islet transplantation and as a source of mesenchymal stem cells. Islet transplantation is a cellular replacement therapy used to treat severe diabetes mellitus; however, its clinical outcome is currently unsatisfactory. Selection of the most appropriate transplantation site is a major factor affecting the clinical success of this therapy. The spleen has long been studied as a candidate site for islet transplantation. Its advantages include physiological insulin drainage and regulation of immunity, and it has recently also been shown to contribute to the regeneration of transplanted islets. However, the efficacy of transplantation in the spleen is lower than that of intraportal transplantation, which is the current representative method of clinical islet transplantation. Safer and more effective methods of islet transplantation need to be established to allow the spleen to be used for clinical transplantation. The spleen is also of interest as a mesenchymal stem cell reservoir. Splenic mesenchymal stem cells contribute to the repair of damaged tissue, and their infusion may thus be a promising therapy for autoimmune diseases, including type 1 diabetes mellitus and Sjogren’s syndrome.

Neutralization Versus Reinforcement of Proinflammatory Cytokines to Arrest Autoimmunity in Type 1 Diabetes

As physiological pathways of intercellular communication produced by all cells, cytokines are involved in the pathogenesis of inflammatory insulitis as well as pivotal mediators of immune homeostasis. Proinflammatory cytokines including interleukins, interferons, transforming growth factor-β, tumor necrosis factor-α, and nitric oxide promote destructive insulitis in type 1 diabetes through amplification of the autoimmune reaction, direct toxicity to β-cells, and sensitization of islets to apoptosis. The concept that neutralization of cytokines may be of therapeutic benefit has been tested in few clinical studies, which fell short of inducing sustained remission or achieving disease arrest. Therapeutic failure is explained by the redundant activities of individual cytokines and their combinations, which are rather dispensable in the process of destructive insulitis because other cytolytic pathways efficiently compensate their deficiency. Proinflammatory cytokines are less redundant in regulation of the inflammatory reaction, displaying protective effects through restriction of effector cell activity, reinforcement of suppressor cell function, and participation in islet recovery from injury. Our analysis suggests that the role of cytokines in immune homeostasis overrides their contribution to β-cell death and may be used as potent immunomodulatory agents for therapeutic purposes rather than neutralized.

TNF, TNF inducers, and TNFR2 agonists: A new path to type 1 diabetes treatment

In the past decade, interest in the century-old tuberculosis vaccine, bacillus Calmette-Guerin (BCG), has been revived for potential new therapeutic uses in type 1 diabetes and other forms of autoimmunity. Diverse clinical trials are now proving the value of BCG in prevention and treatment of type 1 diabetes, in the treatment of new onset multiple sclerosis and other immune conditions. BCG contains the avirulent tuberculosis strain Mycobacterium bovis, a vaccine originally developed for tuberculosis prevention. BCG induces a host response that is driven in part by tumour necrosis factor (TNF). Induction of TNF through BCG vaccination or through selective agonism of TNF receptor 2 (TNFR2) has 2 desired cellular immune effects: (1) selective death of autoreactive T cells and (2) expansion of beneficial regulatory T cells (Tregs). In human clinical trials in both type 1 diabetes and multiple sclerosis, administration of the BCG vaccine to diseased adults has shown great promise. In a Phase I trial in advanced type 1 diabetes (mean duration of diabetes 15 years), 2 BCG vaccinations spaced 4 weeks apart selectively eliminated autoreactive T cells, induced beneficial Tregs, and allowed for a transient and small restoration of insulin production. The advancing global clinical trials using BCG combined with mechanistic data on BCGs induction of Tregs suggest value in this generic agent and possible immune reversal of the type 1 diabetic autoimmune process.

Spleen-Derived Anti-Inflammatory Cytokine IL-10 Stimulated by Adipose Tissue-Derived Stem Cells Protects Against Type 2 Diabetes

Considering that the spleen plays an important role in the occurrence and development of diabetes, we aimed at investigating the role of the spleen in the treatment of type 2 diabetes (T2D) with adipose tissue-derived stem cells (ADSCs). We established a T2D/splenectomy (SPX) rat model by using high-fat diet/streptozotocin administration with SPX, assessed the therapeutic effects of ADSCs, and explored the possible mechanism. A single ADSC infusion was found to ameliorate hyperglycemia and insulin resistance in diabetic rats, accompanied by a considerable number of ADSCs homing to the spleens in T2D rats. Moreover, four times of infusion of ADSCs resulted in a more significant reduction of blood glucose and insulin resistance, whereas SPX exacerbated hyperglycemia and insulin resistance and attenuated the effects of ADSCs. In addition, ADSC infusion promoted anti-inflammatory cytokine interleukin (IL)-10 expression and inhibited pro-inflammatory cytokines IL-6, IL-1β, and tumor necrosis factor (TNF)-α expression in both the spleen and serum of T2D rats without SPX. ADSCs also inhibited serum IL-6, IL-1β, and TNF-α expression, but cannot promote IL-10 expression in T2D rats with SPX. Therefore, these data indicate that the effect of ADSCs ameliorating hyperglycemia and insulin resistance may be partially through promoting spleen-derived anti-inflammatory cytokine IL-10 expression. These novel findings further confirmed the essential role of the spleen in the ADSC treatment of T2D and provide an important theoretical basis for the potential application of ADSCs in T2D therapy.

Effect of Splenectomy to Short Bowel Syndrome in Rats

The aim of this study was to determine the effect of splenectomy in the short bowel syndrome. Twenty-four Wistar-albino rats weighing between 210 and 375 g were used. They were divided into three groups. In group A, short bowel syndrome (SBS) was created by 75 % bowel resection. In group B, SBS and splenectomy was performed. In group C, after transecting the bowel, it was anastomosed. Before and 45 days after the procedures, all rats were weighed. In all three groups, the first and final weight of the rats, the final bowel weight and length, the ileal and jejunal crypt depths, the villus height, the luminal diameter, the bowel wall thickness, and the number of apoptotic cells and mitosis per 100 crypt cell were compared. Periportal fibrosis, infiltration, bile stasis, and bile duct proliferation were detected in liver samples. The rat intestinal length and weight was the least in group B while the jejunal crypt depth was higher in group B than in group A and it was exactly the opposite for the jejunal and ileal villus heights. The ileal and jejunal luminal diameter, the ileal bowel wall thickness, the jejunal and ileal apoptotic cell number, the jejunal mitosis, and the periportal fibrosis were highest in group B. Adding splenectomy to an SBS model has a negative impact on bowel adaptation.

BCG and protection against inflammatory and auto-immune diseases

INTRODUCTION

Bacillus Calmette-Guérin (BCG) is the only available vaccine against tuberculosis. Although its protective efficacy against pulmonary tuberculosis is still under debate, it provides protection against other mycobacterial diseases. BCG is also an effective therapy against superficial bladder cancer and potentially decreases overall childhood mortality. Areas covered: The purpose of this paper is to provide a state-of-the-art summary of the beneficial effects of BCG in inflammatory and auto-immune diseases. As a strong inducer of Th1 type immunity, BCG has been reported to protect against atopic conditions, such as allergic asthma, a Th2-driven disorder. Its protective effect has been well documented in mice, but still awaits definitive evidence in humans. Similarly, murine studies have shown a protective effect of BCG against auto-immune diseases, such as multiple sclerosis and insulin-dependent diabetes, but studies in humans have come to conflicting conclusions. Expert commentary: Studies in mice have shown a beneficial effect of the BCG vaccine against allergic asthma, multiple sclerosis and diabetes. However, the understanding of its mechanism is still fragmentary and requires further in depth research. Some observational or intervention studies in humans have also suggested a beneficial effect, but definitive evidence for this requires confirmation in carefully conducted prospective studies.

The Spleen Is an Ideal Site for Inducing Transplanted Islet Graft Expansion in Mice

Alternative islet transplantation sites have the potential to reduce the marginal number of islets required to ameliorate hyperglycemia in recipients with diabetes. Previously, we reported that T cell leukemia homeobox 1 (Tlx1)+ stem cells in the spleen effectively regenerated into insulin-producing cells in the pancreas of non-obese diabetic mice with end-stage disease. Thus, we investigated the spleen as a potential alternative islet transplantation site. Streptozotocin-induced diabetic C57BL/6 mice received syngeneic islets into the portal vein (PV), beneath the kidney capsule (KC), or into the spleen (SP). The marginal number of islets by PV, KC, or SP was 200, 100, and 50, respectively. Some plasma inflammatory cytokine levels in the SP group were significantly lower than those of the PV group after receiving a marginal number of islets, indicating reduced inflammation in the SP group. Insulin contents were increased 280 days after islet transplantation compared with those immediately following transplantation (p<0.05). Additionally, Tlx1-related genes, including Rrm2b and Pla2g2d, were up-regulated, which indicates that islet grafts expanded in the spleen. The spleen is an ideal candidate for an alternative islet transplantation site because of the resulting reduced inflammation and expansion of the islet graft.

Sansevieria roxburghiana Schult. & Schult. F. (Family: Asparagaceae) Attenuates Type 2 Diabetes and Its Associated Cardiomyopathy

BACKGROUND

Sansevieria roxburghiana Schult. & Schult. F. (Family: Asparagaceae) rhizome has been claimed to possess antidiabetic activity in the ethno-medicinal literature in India. Therefore, present experiments were carried out to explore the protective role of edible (aqueous) extract of S. roxburghiana rhizome (SR) against experimentally induced type 2 diabetes mellitus (T2DM) and its associated cardiomyopathy in Wistar rats.

METHODS

SR was chemically characterized by GC-MS analysis. Antidiabetic activity of SR (50 and 100 mg/kg, orally) was measured in high fat diets (ad libitum) + low-single dose of streptozotocin (35 mg/kg, intraperitoneal) induced type 2 diabetic (T2D) rat. Fasting blood glucose level was measured at specific intermissions. Serum biochemical and inflammatory markers were estimated after sacrificing the animals. Besides, myocardial redox status, expressions of signal proteins (NF-κB and PKCs), histological and ultrastructural studies of heart were performed in the controls and SR treated T2D rats.

RESULTS

Phytochemical screening of the crude extract revealed the presence of phenolic compounds, sugar alcohols, sterols, amino acids, saturated fatty acids within SR. T2D rats exhibited significantly (p < 0.01) higher fasting blood glucose level with respect to control. Alteration in serum lipid profile (p < 0.01) and increased levels of lactate dehydrogenase (p < 0.01) and creatine kinase (p < 0.01) in the sera revealed the occurrence of hyperlipidemia and cell destruction in T2D rats. T2DM caused significant (p < 0.05-0.01) alteration in the biochemical markers in the sera. T2DM altered the redox status (p < 0.05-0.01), decreased (p < 0.01) the intracellular NAD and ATP concentrations in the myocardial tissues of experimental rats. While investigating the molecular mechanism, activation PKC isoforms was observed in the selected tissues. T2D rats also exhibited an up-regulation in nuclear NF-κB (p65) in the cardiac tissues. So, oral administration of SR (50 and 500 mg/kg) could reduce hyperglycemia, hyperlipidemia, membrane disintegration, oxidative stress, vascular inflammation and prevented the activation of oxidative stress induced signaling cascades leading to cell death. Histological and ultra-structural studies of cardiac tissues supported the protective characteristics of SR.

CONCLUSIONS

From the present findings it can be concluded that, SR could offer protection against T2DM and its associated cardio-toxicity via multiple mechanisms viz. hypoglycemic, antioxidant and anti-inflammatory actions.

Resveratrol improves salivary dysfunction in a non-obese diabetic (NOD) mouse model of Sjögren's syndrome

Resveratrol is a natural polyphenol produced by plants in response to environmental stress. This compound has been shown to have pharmacological effects against a wide range of diseases including neurological, hepatic, cardiovascular and autoimmune conditions. The non-obese diabetic (NOD) mouse, in which loss of lacrimal and salivary gland function occurs, has been studied as an animal model for Sjögren’s syndrome. In this study, we confirmed that administration of resveratrol results in increased secretion of saliva in NOD mice. Although resveratrol enhanced Sirt1 activity, inflammatory cell infiltration was not affected. Moreover, expression of the anti-inflammatory cytokine IL-10 in salivary glands was enhanced in the resveratrol-administered group. Thus, we confirmed a novel therapeutic effect for resveratrol on salivary dysfunction in Sjögren’s syndrome.

Toll-Like Receptor 2 Mediates In Vivo Pro- and Anti-inflammatory Effects of Mycobacterium Tuberculosis and Modulates Autoimmune Encephalomyelitis

Mycobacteria display pro- and anti-inflammatory effects in human and experimental pathology. We show here that both effects are mediated by Toll-like receptor 2 (Tlr2), by exploiting a previously characterized Tlr2 variant (Met82Ile). Tlr2 82ile promoted self-specific proinflammatory polarization as well as expansion of ag-specific FoxP3(+) Tregs, while Tlr2 82met impairs the expansion of Tregs and reduces the production of IFN-γ and IL-17 proinflammatory cytokines. Preferential dimerization with Tlr1 or Tlr6 could not explain these differences. In silico, we showed that Tlr2 variant Met82Ile modified the binding pocket for peptidoglycans and participated directly to a putative binding pocket for sugars and cadherins. The distinct pro- and anti-inflammatory actions impacted severity, extent of remission, and distribution of the lesions within the central nervous system of experimental autoimmune encephalomyelitis. Thus, Tlr2 has a janus function in vivo as mediator of the role of bacterial products in balancing pro- and anti-inflammatory immune responses.

Fibroblast Cell-Based Therapy for Experimental Autoimmune Diabetes

Type 1 diabetes (T1D) results from autoimmune destruction of insulin producing β cells of the pancreatic islets. Curbing autoimmunity at the initiation of T1D can result in recovery of residual β cells and consequently remission of diabetes. Here we report a cell-based therapy for autoimmune diabetes in non-obese diabetic (NOD) mice using dermal fibroblasts. This was achieved by a single injection of fibroblasts, expressing the immunoregulatory molecule indoleamine 2,3 dioxygenase (IDO), into peritoneal cavity of NOD mice shortly after the onset of overt hyperglycemia. Mice were then monitored for reversal of hyperglycemia and changes in inflammatory / regulatory T cell profiles. Blood glucose levels dropped into the normal range in 82% of NOD mice after receiving IDO-expressing fibroblasts while all control mice remained diabetic. We found significantly reduced islet inflammation, increased regulatory T cells, and decreased T helper 17 cells and β cell specific autoreactive CD8+ T cells following IDO cell therapy. We further showed that some of intraperitoneal injected fibroblasts migrated to local lymph nodes and expressed co-inhibitory molecules. These findings suggest that IDO fibroblasts therapy can reinstate self-tolerance and alleviate β cell autoreactivity in NOD mice, resulting in remission of autoimmune diabetes.

Current Science of Regenerative Medicine with Stem Cells

Regenerative medicine with stem cells holds great hope for the treatment of degenerative disease. The medical potential of embryonic stem cells remains relatively untapped at this point, and significant scientific hurdles remain to be overcome before these cells might be considered safe and effective for uses in patients. Meanwhile, adult stem cells have begun to show significant capabilities of their own in repair of damaged tissues, in both animal models and early patient trials.

Tumor Necrosis Factor Receptor 2 Restricts the Pathogenicity of CD8(+) T Cells in Mice With Colitis

BACKGROUND & AIMS

Tumor necrosis factor receptor 2 (TNFR2, Tnfrsf1b) regulates multiple aspects of immune function, but little is known about its role in the immunopathogenesis of inflammatory bowel disease (IBD). We investigated whether TNFR2 restricts the activity of specific immune cell subtypes to protect against the development of colitis in mice.

METHODS

Tnfr2(-/-) mice were crossed with interleukin (Il) 10(-/-) mice, which spontaneously develop colitis, to generate Il10(-/-)Tnfr2(-/-) mice. Colonic tissues were collected from Il10(-/-)Tnfr2(-/-) mice along with Il10(-/-) mice (controls) and analyzed by flow cytometry and histology. Bone marrow was transplanted into Il10(-/-) and Il10(-/-)Tnfr2(-/-) mice from Il10(-/-) or Il10(-/-)Tnfr2(-/-) donors by intravenous injection. CD8(+) T cells were neutralized in Il10(-/-)Tnfr2(-/-) mice by intraperitoneal injection of anti-CD8 or isotype control antibodies. Colitis was induced in Rag2(-/-) mice by intravenous injections of naïve CD8(+) T cells isolated from C57BL/6 or Tnfr2(-/-) mice.

RESULTS

Il10(-/-)Tnfr2(-/-) mice spontaneously developed more severe colitis compared with Il10(-/-) controls, characterized by selective expansion of colonic CD8(+) T cells. Transplantation of TNFR2-deficient bone marrow resulted in significantly increased incidence and severity of colitis. Transcriptome analyses showed that the expression of genes regulated by TNFR2 were specific to CD8(+) T cells and included genes associated with risk for IBD. Depletion of CD8(+) T cells from Il10(-/-)Tnfr2(-/-) mice prevented colonic inflammation. Adoptive transfer of TNFR2-null naïve CD8(+) T cells compared with CD8(+) T cells from control mice increased the severity of colitis that developed in Rag2(-/-) mice.

CONCLUSIONS

TNFR2 protects mice from colitis by inhibiting the expansion of colonic CD8(+) T cells. TNFR2 regulates expression of genes that regulate CD8(+) T cells and have been associated with susceptibility to IBD. Disruption in TNFR2 signaling might therefore be associated with pathogenesis. Strategies to increase levels or activity of TNFR2 and thereby reduce the activity of CD8(+) T cells might be developed to treat IBD patients with CD8(+) T cell dysfunction.