Metformin pretreatment suppresses alterations to the articular cartilage ultrastructure and knee joint tissue damage secondary to type 2 diabetes mellitus in rats

Disclosing the impact of metformin and methotrexate in adjuvant arthritis in female rats: molecular docking and biochemical insights on visfatin

Rheumatoid arthritis (RA) is one of the most common systemic autoimmune inflammatory diseases, with a progressive etiology that results in serious complications and a higher chance of early death. Visfatin, an adipokine, is correlated with disease pathologic features and becomes a key biomarker and therapeutic target for RA. This study aimed to evaluate the anti-arthritic activity of metformin (an antidiabetic drug with anti-inflammatory activities) and methotrexate (the first choice for disease-modifying antirheumatic drugs in RA, with diverse adverse effects) in complete Freund's adjuvant (CFA)-induced arthritis in female rats. Treatment outcomes were assessed using arthritis severity, serum levels of inflammatory markers, and pro-inflammatory adipokine (visfatin). In addition to radiological and histopathological examination, and docking analysis. Results showed that Met, MTX, and Met/MTX significantly (p ≤ 0.05) lowered paw swelling and arthritic score, as well as attenuated serum levels of rheumatoid factor (RF), C-reactive protein (CRP), and visfatin. The combined treatment gives the best results. The previously mentioned findings were further confirmed through radiological and histopathological examinations. In conclusion, the co-administration of metformin could potentiate the anti-arthritic activity of methotrexate, providing a medical strategy for arthritis management.

Targeted non-invasive Metformin-Curcumin co-loaded nanohyaluosomes halt osteoarthritis progression and improve articular cartilage structure: A preclinical study

Osteoarthritis (OA) is a degenerative disease that affects the quality of life in elderly and young populations. Current therapies using corticosteroids and non-steroidal anti-inflammatory drugs via parenteral or oral routes show limited ability to retard progression of the disease and achieve long term effectiveness and safety. Herein, the potential of MT-Cur combinatorial nano-formulations in OA management was explored for the first time. MT-Cur loaded nanohyaluosomes (MT-Cur-HL1) were designed for topical administration of the combined therapy in OA. The optimized MT-Cur-HL1 showed particle size 247.7 ± 3.7 nm, zeta potential -37.3 ± 0.4 mV; and entrapment efficiency (%EE) 70.22 %±0.303 and 76.7 %±0.077 for MT and Cur, respectively. MT-Cur-HL1 exhibited sustained drug release over 24 h and were stable over 3 months at 4 °C in terms of P.S., ZP and %EE. A detailed preclinical study, using MIA-induced osteoarthritis rat model, revealed the most significant anti-arthritic effect and halted OA progression of MT-Cur-HL1. This was proved to be mainly through the potentiation of p-AMPK signaling that ultimately led to suppression of its downstream TLR4/ NF-κB signaling pathway with subsequent reduction in MMP13 and ADAMTS5 induced chondrocytes degeneration. This study proved that this trajectory effectively promotes a significant improvement in the articular cartilage structure and reinforcement of joint mobility with an efficient antinociceptive effect. In conclusion, the novel MT-Cur coloaded nanohyaluosomes offer a promising non-invasive approach for the local management of OA.

Metformin as a potential disease-modifying drug in osteoarthritis: a systematic review of pre-clinical and human studies

OBJECTIVE

Osteoarthritis causes significant pain and disability with no approved disease-modifying drugs. We systematically reviewed the evidence from both pre-clinical and human studies for the potential disease-modifying effect of metformin in osteoarthritis.

METHODS

Ovid Medline, Embase and CINAHL were searched between inception and June 2021 using MeSH terms and key words to identify studies examining the association between metformin use and outcome measures related to osteoarthritis. Two reviewers performed the risk of bias assessment and 3 reviewers extracted data independently. Qualitative evidence synthesis was performed. This systematic review is registered on PROSPERO (CRD42021261052 and CRD42021261060).

RESULTS

Fifteen (10 pre-clinical and 5 human) studies were included. Most studies (10 pre-clinical and 3 human) assessed the effect of metformin using knee osteoarthritis models. In pre-clinical studies, metformin was assessed for the effect on structural outcomes (n = 10); immunomodulation (n = 5); pain (n = 4); and molecular pathways of its effect in osteoarthritis (n = 7). For human studies, metformin was evaluated for the effect on structural progression (n = 3); pain (n = 1); and immunomodulation (n = 1). Overall, pre-clinical studies consistently showed metformin having a chondroprotective, immunomodulatory and analgesic effect in osteoarthritis, predominantly mediated by adenosine monophosphate-activated protein kinase activation. Evidence from human studies, although limited, was consistent with findings in pre-clinical studies.

CONCLUSION

We found consistent evidence across pre-clinical and human studies to support a favourable effect of metformin on chondroprotection, immunomodulation and pain reduction in knee osteoarthritis. Further high-quality clinical trials are needed to confirm these findings as metformin could be a novel therapeutic drug for the treatment of osteoarthritis.

The effects of metformin in the treatment of osteoarthritis: Current perspectives

Osteoarthritis is a chronic and irreversible disease of the locomotor system which is closely associated with advancing age. Pain and limited mobility frequently affect the quality of life in middle-aged and older adults. With a global population of more than 350 million, osteoarthritis is becoming a health threat alongside cancer and cardiovascular disease. It is challenging to find effective treatments to promote cartilage repair and slow down disease progression. Metformin is the first-line drug for patients with type 2 diabetes, and current perspectives suggest that it cannot only lower glucose but also has anti-inflammatory and anti-aging properties. Experimental studies applying metformin for the treatment of osteoarthritis have received much attention in recent years. In our review, we first presented the history of metformin and the current status of osteoarthritis, followed by a brief review of the mechanism that metformin acts, involving AMPK-dependent and non-dependent pathways. Moreover, we concluded that metformin may be beneficial in the treatment of osteoarthritis by inhibiting inflammation, modulating autophagy, antagonizing oxidative stress, and reducing pain levels. Finally, we analyzed the relevant evidence from animal and human studies. The potential of metformin for the treatment of osteoarthritis deserves to be further explored.

The Function of Metformin in Aging-Related Musculoskeletal Disorders

Metformin is a widely accepted first-line hypoglycemic agent in current clinical practice, and it has been applied to the clinic for more than 60 years. Recently, researchers have identified that metformin not only has an efficient capacity to lower glucose but also exerts anti-aging effects by regulating intracellular signaling molecules. With the accelerating aging process and mankind’s desire for a long and healthy life, studies on aging have witnessed an unprecedented boom. Osteoporosis, sarcopenia, degenerative osteoarthropathy, and frailty are age-related diseases of the musculoskeletal system. The decline in motor function is a problem that many elderly people have to face, and in serious cases, they may even fail to self-care, and their quality of life will be seriously reduced. Therefore, exploring potential treatments to effectively prevent or delay the progression of aging-related diseases is essential to promote healthy aging. In this review, we first briefly describe the origin of metformin and the aging of the movement system, and next review the evidence associated with its ability to extend lifespan. Furthermore, we discuss the mechanisms related to the modulation of aging in the musculoskeletal system by metformin, mainly its contribution to bone homeostasis, muscle aging, and joint degeneration. Finally, we analyze the protective benefits of metformin in aging-related diseases of the musculoskeletal system.

Metformin and its therapeutic applications in autoimmune inflammatory rheumatic disease

Metformin is a first-line therapeutic agent for type 2 diabetes. Apart from its glucose-lowering effect, metformin is attracting interest regarding possible therapeutic benefits in various other conditions. As metformin regulates cell metabolism, proliferation, growth, and autophagy, it may also modulate immune cell functions. Given that metformin acts on multiple intracellular signaling pathways, including adenosine monophosphate (AMP)-activated protein kinase (AMPK) activation, and that AMPK and its downstream intracellular signaling control the activation and differentiation of T and B cells and inflammatory responses, metformin may exert immunomodulatory and anti- inflammatory effects. The efficacy of metformin has been investigated in preclinical and clinical studies on rheumatoid arthritis, osteoarthritis, systemic lupus erythematosus, Sjögren's syndrome, scleroderma, ankylosing spondylitis, and gout. In this review, we discuss the potential mechanisms through which metformin exerts its therapeutic effects in these diseases, focusing particularly on rheumatoid arthritis and osteoarthritis.

Metformin as a Treatment Strategy for Sjögren's Syndrome

Sjögren's syndrome (SS), a chronic inflammatory disease involving the salivary and lacrimal glands, presents symptoms of sicca as well as systemic manifestations such as fatigue and musculoskeletal pain. Only a few treatments have been successful in management of SS; thus treatment of the disease is challenging. Metformin is the first-line agent for type 2 diabetes and has anti-inflammatory potential. Its immunomodulatory capacity is exerted via activation of 5' adenosine monophosphate-activated protein kinase (AMPK). Metformin inhibits mitochondrial respiratory chain complex I which leads to change in adenosine mono-phosphate (AMP) to adenosine tri-phosphate (ATP) ratio. This results in AMPK activation and causes inhibition of mammalian target of rapamycin (mTOR). mTOR plays an important role in T cell differentiation and mTOR deficient T cells differentiate into regulatory T cells. In this manner, metformin enhances immunoregulatory response in an individual. mTOR is responsible for B cell proliferation and germinal center (GC) differentiation. Thus, reduction of B cell differentiation into antibody-producing plasma cells occurs via downregulation of mTOR. Due to the lack of suggested treatment for SS, metformin has been considered as a treatment strategy and is expected to ameliorate salivary gland function.

Resveratrol ameliorates type 2 diabetes mellitus-induced alterations to the knee joint articular cartilage ultrastructure in rats

Diabetes-induced osteoarthritis (OA) is a chronic inflammatory disease that damages the cartilage in the joints and could lead to disability. The protective effect of the antioxidant and anti-inflammatory agent, resveratrol, against alterations to the knee articular cartilage ultrastructure induced by type 2 diabetes mellitus (T2DM) associated with the inhibition of dyslipidemia, oxidative stress, and inflammation has not been investigated before. Therefore, we modeled OA in rats 10 weeks post diabetic induction using a high carbohydrate and fat diet and a single injection of streptozotocin (50 mg/kg body weight), and the protective group of rats started resveratrol (30 mg/kg; orally) treatment 2 weeks before diabetic induction and continued on resveratrol until the end of the experiment at week 12. Blood chemistry analysis confirmed hyperglycemia (elevated glucose and glycated hemoglobin, HbA1c), dyslipidemia (elevated triglyceride, cholesterol, and low-density lipoprotein-cholesterol), and upregulation of oxidative stress (malondialdehyde) and inflammatory (C-reactive protein and tumor necrosis factor-α) biomarkers in the model group. In addition, using light and electron microscopy examinations, we also observed in the model group substantial damage to the articular cartilage and profound chondrocyte and territorial matrix ultrastructural alterations such as chondrocytes with degenerated nucleus and mitochondria, scarce cytoplasmic processes, and absence of the fine fibrillar appearance of territorial matrix. Resveratrol pretreatment significantly (p ≤ 0.0029) but not completely protected from T2DM-induced OA. We conclude that resveratrol protects against alterations to the articular cartilage ultrastructure induced secondary to T2DM in rats, which is associated with the inhibition of glycemia, hyperlipidemia, and biomarkers of oxidative stress and inflammation.