The Function of Metformin in Aging-Related Musculoskeletal Disorders

Latest advances on new promising molecular-based therapeutic approaches for Huntington's disease

Huntington's disease (HD) is a devastating, autosomal-dominant inherited, neurodegenerative disorder characterized by progressive motor deficits, cognitive impairments, and neuropsychiatric symptoms. It is caused by excessive cytosine-adenine-guanine (CAG) trinucleotide repeats within the huntingtin gene (HTT). Presently, therapeutic interventions capable of altering the trajectory of HD are lacking, while medications for abnormal movement and psychiatric symptoms are limited. Numerous pre-clinical and clinical studies have been conducted and are currently underway to test the efficacy of therapeutic approaches targeting some of these mechanisms with varying degrees of success. In this review, we update the latest advances on new promising molecular-based therapeutic strategies for this disorder, including DNA-targeting techniques such as zinc-finger proteins, transcription activator-like effector nucleases, and CRISPR/Cas9; post-transcriptional huntingtin-lowering approaches such as RNAi, antisense oligonucleotides, and small-molecule splicing modulators; and novel methods to clear the mHTT protein, such as proteolysis-targeting chimeras. We mainly focus on the ongoing clinical trials and the latest pre-clinical studies to explore the progress of emerging potential HD therapeutics.

Causes of In-Hospital Death and Pharmaceutical Associations with Age of Death during a 10-Year Period (2011-2020) in Individuals with and without Diabetes at a Japanese Community General Hospital

Since diabetes and its complications have been thought to exaggerate cardiorenal disease, resulting in a short lifespan, we investigated causes of death and lifespans in individuals with and without diabetes at a Japanese community general hospital during the period from 2011 to 2020. Causes of death and age of death in individuals with and those without diabetes were compared, and associations between medications used and age of death were statistically analyzed. A total of 2326 deaths were recorded during the 10-year period. There was no significant difference between the mean ages of death in individuals with and those without diabetes. Diabetic individuals had higher rates of hepato-pancreatic cancer and cardio-renal failure as causes of death. The prescription rates of antihypertensives, antiplatelets, and statins in diabetic individuals were larger than those in non-diabetic individuals. Furthermore, the use of sulfonyl urea or glinides and insulin was independently and inversely associated with the age of death. In conclusion, individuals with diabetes were treated with comprehensive pharmaceutical interventions and had life spans comparable to those of individuals without diabetes. This study's discovery of an inverse relationship between the use of insulin secretagogues or insulin and the age of death suggests that the prevention of life-threatening hypoglycemia is crucial for individuals with diabetes.

Sarcopenia and Diabetes: A Detrimental Liaison of Advancing Age

Sarcopenia is an age-related clinical complaint characterized by the progressive deterioration of skeletal muscle mass and strength over time. Type 2 diabetes (T2D) is associated with faster and more relevant skeletal muscle impairment. Both conditions influence each other, leading to negative consequences on glycemic control, cardiovascular risk, general health status, risk of falls, frailty, overall quality of life, and mortality. PubMed/Medline, Scopus, Web of Science, and Google Scholar were searched for research articles, scientific reports, observational studies, clinical trials, narrative and systematic reviews, and meta-analyses to review the evidence on the pathophysiology of di-abetes-induced sarcopenia, its relevance in terms of glucose control and diabetes-related outcomes, and diagnostic and therapeutic challenges. The review comprehensively addresses key elements for the clinical definition and diagnostic criteria of sarcopenia, the pathophysiological correlation be-tween T2D, sarcopenia, and related outcomes, a critical review of the role of antihyperglycemic treatment on skeletal muscle health, and perspectives on the role of specific treatment targeting myokine signaling pathways involved in glucose control and the regulation of skeletal muscle metabolism and trophism. Prompt diagnosis and adequate management, including lifestyle inter-vention, health diet programs, micronutrient supplementation, physical exercise, and pharmaco-logical treatment, are needed to prevent or delay skeletal muscle deterioration in T2D.

The Differential Effect of Metformin on Osteocytes, Osteoblasts, and Osteoclasts

PURPOSE OF REVIEW

Metformin is an anti-glycemic agent, which is widely prescribed to diabetes patients. Although its alleged role on bone strength has been reported for some time, this review focuses primarily on the recent mechanistical insights of metformin on osteocytes, osteoblasts, and osteoclasts.

RECENT FINDINGS

Overall, metformin contributed to steering anabolic activity in osteocytes. It caused lower expression in osteocytes of the negative regulators of bone formation sclerostin and DKK1. Likewise, the osteoclastogenesis function of osteoblasts was also skewed towards lower RANKL and higher OPG expressions. Osteoblast lineage cells generally responded to metformin by activating bone formation parameters, such as alkaline phosphatase activity, higher expression of anabolic members of the Wnt pathway, transcription factor Runx2, bone matrix protein proteins, and subsequent mineralization. Metformin affected osteoclast formation and activity in a negative way, reducing the number of multinucleated cells in association with lower expression of typical osteoclast markers and with inhibited resorption. A common denominator studied in all three cell types is its beneficial effect on activating phosphorylated AMP kinase (AMPK) which is associated with the coordination of energy metabolism. Metformin differentially affects bone cells, shifting the balance to more bone formation. Although metformin is a drug prescribed for diabetic patients, the overall bone anabolic effects on osteocytes and osteoblasts and the anti-catabolic effect on osteoclast suggest that metformin could be seen as a promising drug in the bone field.

Insights into the underlying pathogenesis and therapeutic potential of endoplasmic reticulum stress in degenerative musculoskeletal diseases

Degenerative musculoskeletal diseases are structural and functional failures of the musculoskeletal system, including osteoarthritis, osteoporosis, intervertebral disc degeneration (IVDD), and sarcopenia. As the global population ages, degenerative musculoskeletal diseases are becoming more prevalent. However, the pathogenesis of degenerative musculoskeletal diseases is not fully understood. Previous studies have revealed that endoplasmic reticulum (ER) stress is a stress response that occurs when impairment of the protein folding capacity of the ER leads to the accumulation of misfolded or unfolded proteins in the ER, contributing to degenerative musculoskeletal diseases. By affecting cartilage degeneration, synovitis, meniscal lesion, subchondral bone remodeling of osteoarthritis, bone remodeling and angiogenesis of osteoporosis, nucleus pulposus degeneration, annulus fibrosus rupture, cartilaginous endplate degeneration of IVDD, and sarcopenia, ER stress is involved in the pathogenesis of degenerative musculoskeletal diseases. Preclinical studies have found that regulation of ER stress can delay the progression of multiple degenerative musculoskeletal diseases. These pilot studies provide foundations for further evaluation of the feasibility, efficacy, and safety of ER stress modulators in the treatment of musculoskeletal degenerative diseases in clinical trials. In this review, we have integrated up-to-date research findings of ER stress into the pathogenesis of degenerative musculoskeletal diseases. In a future perspective, we have also discussed possible directions of ER stress in the investigation of degenerative musculoskeletal disease, potential therapeutic strategies for degenerative musculoskeletal diseases using ER stress modulators, as well as underlying challenges and obstacles in bench-to-beside research.

Huntington's Disease Drug Development: A Phase 3 Pipeline Analysis

Huntington's Disease (HD) is a severely debilitating neurodegenerative disorder in which sufferers exhibit different combinations of movement disorders, dementia, and behavioral or psychiatric abnormalities. The disorder is a result of a trinucleotide repeat expansion mutation that is inherited in an autosomal dominant manner. While there is currently no treatment to alter the course of HD, there are medications that lessen abnormal movement and psychiatric symptoms. ClinicalTrials.gov was searched to identify drugs that are currently in or have completed phase III drug trials for the treatment of HD. The described phase III trials were further limited to interventional studies that were recruiting, active not recruiting, or completed. In addition, all studies must have posted an update within the past year. PubMed was used to gather further information on these interventional studies. Of the nine clinical trials that met these criteria, eight involved the following drugs: metformin, dextromethorphan/quinidine, deutetrabenazine, valbenazine, Cellavita HD, pridopidine, SAGE-718, and RO7234292 (RG6042). Of these drug treatments, four are already FDA approved. This systematic review provides a resource that summarizes the present therapies for treating this devastating condition that are currently in phase III clinical trials in the United States.

Clinical effect of kyphoplasty in the treatment of osteoporotic thoracolumbar compression fractures in patients with diabetes

Objective

To study the clinical effect and influencing factors of kyphoplasty in the treatment of osteoporotic thoracolumbar compression fractures (OTCF) complicated with type 2 diabetes mellitus (T2DM).

Methods

A total of 472 patients with OTCF complicated with diabetes who were enrolled in our hospital from January to December 2019 were selected as the study subjects, and all patients were treated with percutaneous kyphoplasty (PKP). The effects of gender, age, smoking, drinking, body mass index (BMI), bone mass density (T score), fasting blood glucose level, fasting C-peptide, glycosylated hemoglobin, course of T2DM, vertebral segment and surgical instrument on postoperative improvement were analyzed. The quality of life was evaluated by visual analog score (VAS) and Oswestry disability index (ODI) before PKP and 7 days, and 6 months after PKP, and the patient satisfaction was assessed by the modified Macnab criteria at 6 months postoperatively.

Results

The overall excellent and good rate of evaluation result was satisfactory. In multivariate regression, independent risk factors for poor patient satisfaction included: age ≥70 years (odds ratio (OR) = 2.298, 95% confidence interval [CI] 1.290-4.245, P = 0.025), fasting blood glucose ≥8 mmol/L [OR = 2.657, 95%(CI) 1.288-4.121, P = 0.016], glycosylated hemoglobin ≥6.5 mmol/L [OR = 3.438, 95%(CI) 2.543-4.628, P = 0.001], duration ≥8 years [OR = 1.732, 95%(CI) 1.471-3.253, P = 0.019] and Kyphon instrument [OR = 1.472, 95%(CI) 1.112-2.228, P = 0.018] were independent influencing factors of OTCF complicated with DM.

Conclusion

Kyphoplasty for patients with osteoporotic thoracolumbar compression fractures complicated with diabetes can achieve a satisfactory clinical effect, the curative effect is affected by many factors, attention to these factors can improve the clinical effect.

Metformin Attenuates UVA-Induced Skin Photoaging by Suppressing Mitophagy and the PI3K/AKT/mTOR Pathway

Ultraviolet (UV) radiation is a major cause of photoaging that can induce DNA damage, oxidative stress, and cellular aging. Metformin (MF) can repair DNA damage, scavenge reactive oxygen species (ROS), and protect cells. However, the mechanism by which MF inhibits cell senescence in chronic skin damage induced by UVA is unclear. In this study, human foreskin fibroblasts (HFFs) treated with UVA were used as an in vitro model and UVA-induced skin photoaging in Kunming mice was used as an in vivo model to investigate the potential skin protective mechanism of MF. The results revealed that MF treatment attenuated UVA-induced cell viability, skin aging, and activation of the PI3K/AKT/mTOR signaling pathway. Furthermore, MF treatment alleviated the mitochondrial oxidative stress and decreased mitophagy. Knockdown of Parkin by siRNA increased the clearance of MF in senescent cells. The treatment of Kunming mice with MF at a dose of 10 mg/kg/day significantly reduced UVA-induced skin roughness, epidermal thinning, collagen degradation, and skin aging. In conclusion, our experimental results suggest that MF exerts anti-photoaging effects by inhibiting mitophagy and the PI3K/AKT/mTOR signaling pathway. Therefore, our study improves the current understanding of the protective mechanism of MF against photoaging.

The role of AMPK-dependent pathways in cellular and molecular mechanisms of metformin: a new perspective for treatment and prevention of diseases

Metformin can suppress gluconeogenesis and reduce blood sugar by activating adenosine monophosphate-activated protein kinase (AMPK) and inducing small heterodimer partner (SHP) expression in the liver cells. The main mechanism of metformin’s action is related to its activation of the AMPK enzyme and regulation of the energy balance. AMPK is a heterothermic serine/threonine kinase made of a catalytic alpha subunit and two subunits of beta and a gamma regulator. This enzyme can measure the intracellular ratio of AMP/ATP. If this ratio is high, the amino acid threonine 172 available in its alpha chain would be activated by the phosphorylated liver kinase B1 (LKB1), leading to AMPK activation. Several studies have indicated that apart from its significant role in the reduction of blood glucose level, metformin activates the AMPK enzyme that in turn has various efficient impacts on the regulation of various processes, including controlling inflammatory conditions, altering the differentiation pathway of immune and non-immune cell pathways, and the amelioration of various cancers, liver diseases, inflammatory bowel disease (IBD), kidney diseases, neurological disorders, etc. Metformin’s activation of AMPK enables it to control inflammatory conditions, improve oxidative status, regulate the differentiation pathways of various cells, change the pathological process in various diseases, and finally have positive therapeutic effects on them. Due to the activation of AMPK and its role in regulating several subcellular signalling pathways, metformin can be effective in altering the cells’ proliferation and differentiation pathways and eventually in the prevention and treatment of certain diseases.