The effects of addition of coenzyme Q10 to metformin on sirolimus-induced diabetes mellitus

A comprehensive update of the metabolic and toxicological considerations for immunosuppressive drugs used during pancreas transplantation

INTRODUCTION

Despite significant advancements in immunosuppressive regimens and surgical techniques, the prevalence of adverse events related to immunosuppression remains a major challenge affecting the long-term survival rates of pancreas and kidney allografts.

AREAS COVERED

This article presents a comprehensive review of the literature and knowledge (Jan/2012-Feb/2023) concerning glucose metabolism disorders and nephrotoxicity associated with tacrolimus and mammalian target of rapamycin inhibitors (mTORi). Novel signaling pathways potentially implicated in these adverse events are discussed. Furthermore, we extensively examine the findings from clinical trials evaluating the efficacy and safety of tacrolimus, mTORi, and steroid minimization.

EXPERT OPINION

Tacrolimus-based regimens continue to be the standard treatment following pancreas transplants. However, prolonged use of tacrolimus and mTORi may lead to hyperglycemia and nephrotoxicity. Understanding and interpreting experimental data, particularly concerning novel signaling pathways beyond calcineurin-NFAT and mTOR pathways, can offer valuable insights for therapeutic interventions to mitigate hyperglycemia and nephrotoxicity. Additionally, critically analyzing clinical trial results can identify opportunities for personalized safety-based approaches to minimize side effects. It is imperative to conduct randomized-controlled studies to assess the impact of mTORi use and steroid-free protocols on pancreatic allograft survival. Such studies will aid in tailoring treatment strategies for improved transplant outcomes.

Effect of Sirolimus/Metformin Co-Treatment on Hyperglycemia and Cellular Respiration in BALB/c Mice

Sirolimus (SRL) is widely used as an immunosuppressant to prevent graft rejection, despite the risk of impairing glucose metabolism. Metformin (MET) can reduce the detrimental effects of SRL in many patients, including diabetes and renal transplant recipients. Limited in vivo studies have reported on SRL and MET therapy, particularly in relation to cellular bioenergetics, glucose metabolism, and insulin resistance. Herein, we investigated the efficacy of SRL and MET co-treatment in BALB/c mice over 4 weeks. Balb/c mice (4-6 weeks old) were divided into four groups and injected intraperitoneally (i.p.) with water (control, CTRL), MET (200 µg/g), SRL (5 µg/g), or MET (200 µg/g) +SRL (5 µg/g) over a period of one month. We evaluated the body weight, food consumption rate, random blood glucose (BG), insulin levels, serum biochemistry parameters (ALT, Albumin, BUN, Creatinine), and histomorphology in all groups using standardized techniques and assays. All drug-treated groups showed a statistically significant decrease in weight gain compared to the CTRL group, despite normal food intake. Treatment with SRL caused elevated BG and insulin levels, which were restored with SRL + MET combination. Serum biochemical parameters were within the normal range in all the studied groups. SRL+ MET co-treatment decreased liver cellular respiration and increased cellular ATP levels in the liver. In the pancreas, co-treatment resulted in increased cellular respiration and decreased cellular ATP levels. Liver and pancreatic histology were unchanged in all groups. This study showed that co-treatment of SRL with MET alleviates hyperglycemia induced by SRL without any deleterious effects. These results provide initial insights into the potential use of SRL + MET therapy in various settings.

Rapamycin/metformin co-treatment normalizes insulin sensitivity and reduces complications of metabolic syndrome in type 2 diabetic mice

Rapamycin treatment has positive and negative effects on progression of type 2 diabetes (T2D) in a recombinant inbred polygenic mouse model, male NONcNZO10/LtJ (NcZ10). Here, we show that combination treatment with metformin ameliorates negative effects of rapamycin while maintaining its benefits. From 12 to 30 weeks of age, NcZ10 males were fed a control diet or diets supplemented with rapamycin, metformin, or a combination of both. Rapamycin alone reduced weight gain, adiposity, HOMA-IR, and inflammation, and prevented hyperinsulinemia and pre-steatotic hepatic lipidosis, but exacerbated hyperglycemia, hypertriglyceridemia, and pancreatic islet degranulation. Metformin alone reduced hyperinsulinemia and circulating c-reactive protein, but exacerbated nephropathy. Combination treatment retained the benefits of both while preventing many of the deleterious effects. Importantly, the combination treatment reversed effects of rapamycin on markers of hepatic insulin resistance and normalized systemic insulin sensitivity in this inherently insulin-resistant model. In adipose tissue, rapamycin attenuated the expression of genes associated with adipose tissue expansion (Mest, Gpam), inflammation (Itgam, Itgax, Hmox1, Lbp), and cell senescence (Serpine1). In liver, the addition of metformin counteracted rapamycin-induced alterations of G6pc, Ppara, and Ldlr expressions that promote hyperglycemia and hypertriglyceridemia. Both rapamycin and metformin treatment reduced hepatic Fasn expression, potentially preventing lipidosis. These results delineate a state of "insulin signaling restriction" that withdraws endocrine support for further adipogenesis, progression of the metabolic syndrome, and the development of its comorbidities. Our results are relevant for the treatment of T2D, the optimization of current rapamycin-based treatments for posttransplant rejection and various cancers, and for the development of treatments for healthy aging.

Identification of the shared gene signatures and pathways between sarcopenia and type 2 diabetes mellitus

Background

Sarcopenia is characterized by the age-associated loss of skeletal muscle mass and strength that develops progressively and plays an important role in the disability of the elderly. It has received growing attention over the last decade and has been implicated as both a cause and consequence of type 2 diabetes mellitus (T2DM). The existence of T2DM could increase the risk of developing sarcopenia through multiple mechanisms including advanced glycation end-product accumulation. Meanwhile, sarcopenia would alter glucose disposal and may contribute to the development and progression of T2DM due to reduced muscle mass.

Methods

We implemented transcriptomic analysis of skeletal muscle biopsy specimens in sarcopenia patients and proliferating myoblasts or differentiated myotubes from individuals with T2DM. Related microarray data were selected from Gene Expression Omnibus (GEO) to screen the genes, which were differentially expressed for sarcopenia and T2DM. Multiple combinatorial statistical methods and bioinformatics tools were used to analyze the common DEGs. Meanwhile, functional enrichment analysis was also carried out. Furthermore, we constructed the protein-protein interaction (PPI), as well as transcription factor (TF)-gene interactions network and TF-miRNA coregulatory network. Finally, based on the common DEGs, drug compounds were speculated using the Drug Signatures database (DSigDB).

Results

A total of 1765 and 2155 DEGs of sarcopenia and T2DM were screened, respectively. 15 common genes (LXN, CIB2, PEA15, KANK2, FGD1, NMRK1, PLCB1, SEMA4G, ADARB1, UPF3A, CSTB, COL3A1, CD99, ETV3, FJX1) correlated with sarcopenia and T2DM simultaneously were then identified, and 3 genes (UPF3A, CSTB and PEA15) of them were regarded as hub genes. Functional enrichment analysis revealed several shared pathways between two diseases. In addition, according to the TF-gene interactions network and TF-miRNA coregulatory network, part of TF and miRNA may be identified as key regulator in sarcopenia and T2DM at the same time (e.g., CREM and miR-155). Notably, drug compounds for T2DM and sarcopenia were also suggested, such as coenzyme Q10.

Conclusion

This study revealed that sarcopenia and T2DM may share similar pathogenesis and provided new biological targets and ideas for early diagnosis and effective treatment of sarcopenia and T2DM.

Water-soluble coenzyme Q10 provides better protection than lipid-soluble coenzyme Q10 in a rat model of chronic tacrolimus nephropathy

BACKGROUND/AIMS

Coenzyme Q10 (CoQ10), is a promising antioxidant; however, low bioavailability owing to lipid-solubility is a limiting factor. We developed water-soluble CoQ10 (CoQ10-W) and compared its effects with conventional lipid-soluble CoQ10 (CoQ10-L) in an experimental model of chronic tacrolimus (Tac) nephropathy.

METHODS

CoQ10-W was developed from a glycyrrhizic-carnitine mixed layer CoQ10 micelle based on acyltransferases. Chronic nephropathy was induced in rats with 28-day Tac treatment; they were concomitantly treated with CoQ10-L or CoQ10-W. CoQ10 level in plasma and kidney were measured using liquid chromatography-mass spectrometry. CoQ10-W and CoQ10-L effects on Tac-induced nephropathy were assessed in terms of renal function, histopathology, oxidative stress, and apoptotic cell death. Their effects on cell viability and reactive oxygen species (ROS) production were assessed in cultured proximal tubular cells, human kidney 2 (HK-2) cells.

RESULTS

The plasma CoQ10 level was significantly higher in the CoQ10-W group than in the CoQ10-L group. Tac treatment caused renal dysfunction, typical pathologic lesions, and oxidative stress markers. Serum creatinine was restored in the Tac + CoQ10-L or CoQ10-W groups compared with that in the Tac group. CoQ10-W administration reduced oxidative stress and apoptosis markers. Mitochondrial ultrastructure assessment revealed that the addition of CoQ10-L or CoQ10-W with Tac increased mitochondrial size and number than Tac treatment alone. In vitro investigations revealed that both CoQ10-L and CoQ10-W improved cell viability and reduced ROS production in the Tac-induced HK-2 cell injury.

CONCLUSION

CoQ10-W has a better therapeutic effect in Tac-induced renal injury than conventional CoQ10-L, possibly associated with improved CoQ10 bioavailability.

The therapeutic efficacy of water-soluble coenzyme Q10 in an experimental model of tacrolimus-induced diabetes mellitus

BACKGROUND/AIMS

Coenzyme Q10 (CoQ10) has antioxidant effects and is commercially available and marketed extensively. However, due to its low bioavailability, its effects are still controversial. We developed a water-soluble CoQ10-based micelle formulation (CoQ10-W) and tested it in an experimental model of tacrolimus (TAC)-induced diabetes mellitus (DM).

METHODS

We developed CoQ10-W from a glycyrrhizic-carnitine mixed layer CoQ10 micelle preparation based on acyltransferases. TAC-induced DM rats were treated with either lipid-soluble CoQ10 (CoQ10-L) or CoQ10-W for 4 weeks. Their plasma and pancreatic CoQ10 concentrations were measured using liquid chromatography- tandem mass spectrometry. The therapeutic efficacies of CoQ10-W and CoQ10-L on TAC-induced DM were compared using functional and morphological parameters and their effects on cell viability and reactive oxygen species (ROS) production were also evaluated in cultured rat insulinoma cells.

RESULTS

The plasma CoQ10 level was significantly increased in the CoQ10-W group compared to that in the CoQ10-L group. Intraperitoneal glucose tolerance tests and glucose-stimulated insulin secretion revealed that CoQ10-W controlled hyperglycemia and restored insulin secretion significantly better than CoQ10-L. The TAC-mediated decrease in pancreatic islet size was significantly attenuated by CoQ10-W but not by CoQ10-L. TAC-induced oxidative stress and apoptosis were significantly more reduced by CoQ10-W than CoQ10-L. Electron microscopy revealed that CoQ10-W restored TAC-induced attenuation in the number of insulin granules and the average mitochondrial area, unlike CoQ10-L. In vitro studies showed that CoQ10-L and CoQ10-W both improved cell viability and reduced ROS production in TAC-treated islet cells to a similar extent.

CONCLUSION

CoQ10-W has better therapeutic efficacy than CoQ10-L in TAC-induced DM.

Endothelial dysfunction and inflammatory biomarkers as a response factor of concurrent coenzyme Q10 add-on metformin in patients with type 2 diabetes mellitus

OBJECTIVES

The objective of the study was to evaluate the effect of metformin alone or in combination with coenzyme Q10 (CoQ10) on inflammatory changes and endothelial dysfunction in patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

A total numbers of 54 patients with T2DM compared to 30 healthy subjects were divided into three groups: Group A (n = 30): healthy subjects without any medications; Group B (n = 24): T2DM patients treated with metformin 1 g/day; and Group C (n = 30): T2DM patients treated with metformin 1 g/day plus CoQ10, 300 mg/day. The duration of the study was 8 weeks. Fasting blood glucose, glycated hemoglobin, lipid profile, blood pressure variables, fasting insulin, insulin resistance, homeostatic model assessment of insulin resistance, vascular cell adhesion molecule 1 (VCAM-1), and E-selectin were measured before and after therapy.

RESULTS

Metformin and/or CoQ10 therapy illustrated an insignificant effect on the fody mass index. This combination produced a significant improvement of metabolic changes in patients with T2DM (P < 0.01). sVCAM-1 serum level was decreased significantly after the initiation of metformin and/or CoQ10 therapy compared to the baseline P < 0.05. E-selectin was declined significantly following metformin monotherapy and after metformin plus CoQ10 therapy (P = 0.0001).

CONCLUSION

CoQ10 add-on metformin therapy improves endothelial dysfunction and inflammatory changes in patients with T2DM alongside with amelioration of metabolic profile.

Coenzyme Q10 alleviates tacrolimus-induced mitochondrial dysfunction in kidney

The major side effect of tacrolimus (Tac) is nephrotoxicity. We studied whether supplementation of coenzyme Q₁₀, (CoQ₁₀) a potent antioxidant, can reduce Tac-induced nephrotoxicity via improving mitochondrial function. In an in vitro study, CoQ₁₀ reduced the production of Tac-induced mitochondrial reactive oxygen species and abolished the loss of mitochondrial membrane potential in proximal tubular cell line. Assessment of mitochondrial function revealed that CoQ₁₀ decreased oxygen consumption and mitochondrial respiration rate increased by Tac, suggesting improvement of mitochondrial function to synthesize ATP with CoQ₁₀ treatment. The effect of the CoQ₁₀ in vitro study was observed in an experimental model of chronic Tac-induced nephropathy. CoQ₁₀ attenuated Tac-induced oxidative stress and was accompanied by function and histologic improvement. On electron microscopy, addition of CoQ₁₀ increased not only the number but also the volume of mitochondria compared with Tac treatment only. Our data indicate that CoQ₁₀ improves Tac-induced mitochondrial dysfunction in kidney. Supplementary CoQ₁₀ treatment may be a promising approach to reduce Tac-induced nephrotoxicity.-Yu, J. H., Lim, S. W., Luo, K., Cui, S., Quan, Y., Shin, Y. J., Lee, K. E., Kim, H. L., Ko, E. J., Chung, B. H., Kim, J. H., Chung, S. J., Yang, C. W. Coenzyme Q₁₀ alleviates tacrolimus-induced mitochondrial dysfunction in kidney.

Therapeutic potential of coenzyme Q10 in mitochondrial dysfunction during tacrolimus-induced beta cell injury

We previously reported that oxidative stress induced by long-term tacrolimus treatment impairs mitochondrial function in pancreatic beta cells. In this study, we aimed to investigate the therapeutic potential of coenzyme Q₁₀, which is known to be a powerful antioxidant, in mitochondrial dysfunction in tacrolimus-induced diabetic rats. In a rat model of tacrolimus-induced diabetes mellitus, coenzyme Q₁₀ treatment improved pancreatic beta cell function. The administration of coenzyme Q₁₀ improved insulin immunoreactivity within islets, which was accompanied by reductions in oxidative stress and apoptosis. Assessment of the mitochondrial ultrastructure by electron microscopy revealed that coenzyme Q₁₀ treatment increased the size, number, and volume of mitochondria, as well as the number of insulin granules compared with that induced by tacrolimus treatment alone. An in vitro study using a pancreatic beta cell line showed that tacrolimus treatment increased apoptosis and the production of mitochondrial reactive oxygen species, while cotreatment with coenzyme Q₁₀ effectively attenuated these alterations. At the subcellular level, tacrolimus-induced impairment of mitochondrial respiration was significantly improved by coenzyme Q₁₀, as evidenced by the increased mitochondrial oxygen consumption and ATP production. Our data indicate that coenzyme Q₁₀ plays an important role in reducing tacrolimus-induced oxidative stress and protects the mitochondria in pancreatic beta cells. These findings suggest that supplementation with coenzyme Q₁₀ has beneficial effects in tacrolimus-induced diabetes mellitus.