Diabetes Mellitus Is a Chronic Disease that Can Benefit from Therapy with Induced Pluripotent Stem Cells

Addressing the impact of high glucose microenvironment on the immunosuppressive characteristics of human mesenchymal stem cells

Mesenchymal stem cells (MSCs) are a therapeutically efficient type of stem cells validated by their ability to treat many inflammatory and chronic conditions. The biological and therapeutic characteristics of MSCs can be modified depending on the type of microenvironment at the site of transplantation. Diabetes mellitus (DM) is a commonly diagnosed metabolic disease characterized by hyperglycemia, which alters over time the cellular and molecular functions of many cells and causes their damage. Hyperglycemia can also impact the success rate of MSCs transplantation; therefore, it is extremely significant to investigate the effect of high glucose on the biological and therapeutic attributes of MSCs, particularly their immunomodulatory abilities. Thus, in this study, we explored the effect of high glucose on the immunosuppressive characteristics of human adipose tissue-derived mesenchymal stem cells (hAD-MSCs). We found that hAD-MSCs cultured in high glucose lost their immunomodulatory abilities and became detectable by immune cells. The decline in the immunosuppressive capabilities of hAD-MSCs was mediated by significant decrease in the levels of IDO, IL-10, and complement factor H and substantial increase in the activity of immunoproteasome. The protein levels of AMP-activated protein kinase (AMPK) and phosphofructokinase-1 (PFK-1), which are integral regulators of glycolysis, revealed a marked decline in high glucose exposed MSCs. The findings of our study indicated the possibility of immunomodulatory shift in MSCs after being cultured in high glucose, which can be translationally employed to explain their poor survival and short-lived therapeutic outcomes in diabetic patients.

Lactate-induced autophagy activation: unraveling the therapeutic impact of high-intensity interval training on insulin resistance in type 2 diabetic rats

Impaired autophagy is a hallmark of diabetes. The current study proposed to investigate if high intensity interval training (HIIT) induced lactate accumulation could stimulate autophagy in type 2 diabetic male rats. 28 male Wistar rats were randomly assigned into four groups: Healthy Control (CO), Diabetes Control (T2D), Exercise (EX), and Diabetes + Exercise (T2D + EX). Diabetes was induced by feeding high-fat diet and administrating single dose of streptozotocin (35 mg/kg). After becoming diabetic, the animals in the exercise groups (EX and T2D + EX) performed an eight-week HIIT (4-10 interval, 80-100% Vmax, 5 days per week). Serum levels of lactate, glucose and insulin as well as the levels of lactate, pyruvate, lactate transporter monocarboxylate transporter 1 (MCT1), phosphorylated mitogen-activated protein kinases (p-MAP 1 and 2), phosphorylated extracellular signal-regulated protein kinases 1 and 2 (p-ERK 1 and 2), mammalian target of rapamycin (p-mTOR), ribosomal protein S6 kinase beta-1 (p-70S6k), p90 ribosomal S6 kinases (p-90RSK), autophagy related 7 (ATG7), Beclin-1, microtubule-associated protein 1A/1B, and 2A/2B -light chain 3 levels (LC3-I), (LC3- II), (LC3I/LC3II) in soleus muscle were measured. Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) and serum glucose was lower in T2D + EX compared to T2D group (P < 0.0001). While serum and soleus muscle levels of lactate was not different between T2D and T2D + Ex, the levels of Pyruvate (P < 0.01), MCT1, p-ERK1/2, p-mTOR, p70S6k, P-90RSK, ATG7, LC3-II, and LC3-II/LC3I ratios were higher in T2D + EX compared to T2D group (P < 0.0001). We concluded that eight weeks of high-intensity interval training could activated ERK/P90SRK while inhibiting mTOR/P70S6K signaling pathway in lactate dependent manner. It means increased autophagy which resulted in improve insulin resistance (IR) and reduce blood glucose.

Human mesenchymal stem cells exhibit altered mitochondrial dynamics and poor survival in high glucose microenvironment

BACKGROUND

Mesenchymal stem cells (MSCs) are a type of stem cells that possess relevant regenerative abilities and can be used to treat many chronic diseases. Diabetes mellitus (DM) is a frequently diagnosed chronic disease characterized by hyperglycemia which initiates many multisystem complications in the long-run. DM patients can benefit from MSCs transplantation to curb down the pathological consequences associated with hyperglycemia persistence and restore the function of damaged tissues. MSCs therapeutic outcomes are found to last for short period of time and ultimately these regenerative cells are eradicated and died in DM disease model.

AIM

To investigate the impact of high glucose or hyperglycemia on the cellular and molecular characteristics of MSCs.

METHODS

Human adipose tissue-derived MSCs (hAD-MSCs) were seeded in low (5.6 mmol/L of glucose) and high glucose (25 mmol/L of glucose) for 7 d. Cytotoxicity, viability, mitochondrial dynamics, and apoptosis were deplored using specific kits. Western blotting was performed to measure the protein expression of phosphatidylinositol 3-kinase (PI3K), TSC1, and mammalian target of rapamycin (mTOR) in these cells.

RESULTS

hAD-MSCs cultured in high glucose for 7 d demonstrated marked decrease in their viability, as shown by a significant increase in lactate dehydrogenase (P < 0.01) and a significant decrease in Trypan blue (P < 0.05) in these cells compared to low glucose control. Mitochondrial membrane potential, indicated by tetramethylrhodamine ethyl ester (TMRE) fluorescence intensity, and nicotinamide adenine dinucleotide (NAD+)/NADH ratio were significantly dropped (P < 0.05 for TMRE and P < 0.01 for NAD+/NADH) in high glucose exposed hAD-MSCs, indicating disturbed mitochondrial function. PI3K protein expression significantly decreased in high glucose culture MSCs (P < 0.05 compared to low glucose) and it was coupled with significant upregulation in TSC1 (P < 0.05) and downregulation in mTOR protein expression (P < 0.05). Mitochondrial complexes I, IV, and V were downregulated profoundly in high glucose (P < 0.05 compared to low glucose). Apoptosis was induced as a result of mitochondrial impairment and explained the poor survival of MSCs in high glucose.

CONCLUSION

High glucose impaired the mitochondrial dynamics and regulatory proteins in hAD-MSCs ensuing their poor survival and high apoptosis rate in hyperglycemic microenvironment.

Fatigue among Patients with Type 2 Diabetes Mellitus: The Impact of Spirituality and Illness Perceptions

Type 2 Diabetes Mellitus (T2DM) can cause fatigue, negatively affecting the daily functioning and health of individuals. The purpose of this study was to investigate the impact of spirituality and illness perceptions on fatigue among patients with Type 2 Diabetes Mellitus. In this cross-sectional, descriptive study, 100 patients with Type 2 Diabetes Mellitus completed the Fatigue Assessment Scale, the FACIT Sp-12 scale, and the Illness Perception Questionnaire-Revised assessing fatigue, spirituality, and illness perceptions, respectively. The mean age of the sample was 52.18 ± 15.53 years and 65% were insulin-treated patients. The mean score for the FACIT Sp-12 scale was 31.86 ± 7.7, for the FAS 27.0 ± 7.63, and for the Consequences and Emotional Representations of IPQ-R 25.5 ± 5.3. Statistically negative significant correlations were observed between the FACIT Sp-12 total score and the FAS subscales (r = -0.44 to -0.48, p < 0.01) and positive correlations between the "IP-Consequences and Emotional Representations" subscales and FAS scores. The total score of the FACIT Sp-12 (β = -0.35) was a negative predictor while Consequences and Emotional Representations (β = 0.28) were positive predictors of the total FAS Score. Participants scored moderate levels of total fatigue. Spirituality and positive illness perceptions may have a protective effect on the fatigue of patients with Type 2 Diabetes Mellitus.

Aerobic Exercise Ameliorates Muscle Atrophy Induced by Methylglyoxal via Increasing Gastrocnemius and Extensor Digitorum Longus Muscle Sensitivity

Muscle atrophy is characterized by the loss of muscle function. Many efforts are being made to prevent muscle atrophy, and exercise is an important alternative. Methylglyoxal is a well-known causative agent of metabolic diseases and diabetic complications. This study aimed to evaluate whether methylglyoxal induces muscle atrophy and to evaluate the ameliorative effect of moderate-intensity aerobic exercise in a methylglyoxal-induced muscle atrophy animal model. Each mouse was randomly divided into three groups: control, methylglyoxal-treated, and methylglyoxal-treated within aerobic exercise. In the exercise group, each mouse was trained on a treadmill for 2 weeks. On the last day, all groups were evaluated for several atrophic behaviors and skeletal muscles, including the soleus, plantaris, gastrocnemius, and extensor digitorum longus were analyzed. In the exercise group, muscle mass was restored, causing in attenuation of muscle atrophy. The gastrocnemius and extensor digitorum longus muscles showed improved fiber cross-sectional area and reduced myofibrils. Further, they produced regulated atrophy-related proteins (i.e., muscle atrophy F-box, muscle RING-finger protein-1, and myosin heavy chain), indicating that aerobic exercise stimulated their muscle sensitivity to reverse skeletal muscle atrophy. In conclusion, shortness of the gastrocnemius caused by methylglyoxal may induce the dynamic imbalance of skeletal muscle atrophy, thus methylglyoxal may be a key target for treating skeletal muscle atrophy. To this end, aerobic exercise may be a powerful tool for regulating methylglyoxal-induced skeletal muscle atrophy.

Diabetes and deaths of COVID-19 patients: Systematic review of meta-analyses

Background

COVID-19 is affecting all kinds of patients including diabetics. This article provides an overview of conducted meta-analyses regarding the effect of diabetes on the deaths of COVID-19 patients.

Methodology

The study was conducted as per preferred reporting items for systematic reviews and meta-analysis (PRISMA) statement.

Data sources

The relevant meta-analyses were searched on PubMed till April 2021 and data was extracted from 24 relevant meta-analyses. The overall estimate was calculated in terms of odds ratio or relative risk with a 95% confidence interval.

Results

A total of 09 meta-analyses showed the association of diabetes with the death of COVID-19 patients and 15 meta-analyses have reported the association of diabetes with other comorbidities in the death of COVID-19 patients. The pooled odds ratio or relative risk has shown a significant association of diabetes alone or its associated comorbidities with deaths of COVID-19 patients.

Conclusion

Patients with diabetes and its associated comorbidities need more monitoring if get SARS-Cov-2 infection to reduce deaths.

Insulin growth factor binding protein-3 enhances dental implant osseointegration against methylglyoxal-induced bone deterioration in a rat model

PURPOSE

The aim of this study was to determine the effect of insulin growth factor binding protein-3 (IGFBP-3) on the inhibition of glucose oxidative stress and promotion of bone formation near the implant site in a rat model of methylglyoxal (MGO)-induced bone loss.

METHODS

An in vitro study was performed in MC3T3 E1 cells treated with chitosan gold nanoparticles (Ch-GNPs) conjugated with IGFBP-3 cDNA followed by MGO. An in vivo study was conducted in a rat model induced by MGO administration after the insertion of a dental implant coated with IGFBP-3.

RESULTS

MGO treatment downregulated molecules involved in osteogenic differentiation and bone formation in MC3T3 E1 cells and influenced the bone mineral density and bone volume of the femur and alveolar bone. In contrast, IGFBP-3 inhibited oxidative stress and inflammation and enhanced osteogenesis in MGO-treated MC3T3 E1 cells. In addition, IGFBP-3 promoted bone formation by reducing inflammatory proteins in MGO-administered rats. The application of Ch-GNPs conjugated with IGFBP-3 as a coating of titanium implants enhanced osteogenesis and the osseointegration of dental implants.

CONCLUSIONS

This study demonstrated that IGFBP-3 could be applied as a therapeutic component in dental implants to promote the osseointegration of dental implants in patients with diabetes, which affects MGO levels.

Exosomes derived from induced pluripotent stem cells suppresses M2-type macrophages during pulmonary fibrosis via miR-302a-3p/TET1 axis

Idiopathic pulmonary fibrosis (PF) is a type of chronic lung disease. Here, we investigated the effect of induced pluripotent stem cell (iPSC)-derived exosomes (iPSC-exosomes) on M2-type macrophages which play a critical role in pulmonary fibrosis. Exosomes were purified from the conditioned medium of iPSCs. Mice models of pulmonary fibrosis were established by intratracheal instillation with 5 mg/kg bleomycin. Thereafter, the histopathological changes and collagen deposition were detected by HE and masson staining. Meanwhile the level of M2-type macrophages was elevated by immunofluorescence staining with F4/80 and Arg-1. Luciferase reporter assay was conducted to verify the binding of miR-302a-3p to ten-eleven translocation 1 (TET1). Our results showed that, after treatment with iPSC-exosomes, the pulmonary fibrosis induced by bleomycin was relieved, with less collagen deposition. In addition, the increased M2-type macrophages in PF mice were reduced upon treatment with iPSC-exosomes. Moreover, we found that the iPSC-exosomes showed higher level of miR-302a-3p. Interestingly, the level of miR-302a-3p in the lungs of PF mice was increased upon treatment with iPSC-exosomes. Furthermore, we verified that TET1 was a direct target of miR-302a-3p. Up-regulation of miR-302a-3p or TET1 silencing repressed M2-type macrophages. Down-regulation of miR-302a-3p abolished the beneficial effects of iPSC-exosomes on pulmonary fibrosis. Collectively, our study revealed that iPSC-exosomes delivered miR-302a-3p to suppress the M2-type macrophages via targeting TET1, thus mitigating pulmonary fibrosis. This study indicates that iPSC-exosomes may become a potential therapeutic agent for pulmonary fibrosis.