Total Serum Testosterone and Western Ontario and McMaster Universities Osteoarthritis Index Pain and Function Among Older Men and Women With Severe Knee Osteoarthritis

Testosterone Replacement Therapy in Orthopaedic Surgery

Testosterone replacement therapy (TRT) is an indicated treatment of several medical conditions including late-onset hypogonadism, congenital syndromes, and gender affirmation hormonal therapy. Increasing population age, medical benefits, and public awareness of TRT have resulted in increased prevalence of its utilization. However, TRT is not without concern for adverse risks including venous thromboembolic complications, cardiovascular events, and prostate issues. In the field of orthopaedic surgery, research is beginning to delineate the complex relationship between TRT and the development of orthopaedic conditions and potential effects on surgical interventions and outcomes. In this review, we discuss current literature surrounding TRT and subsequent development of osteoarthritis, incidence of total joint arthroplasty, musculotendinous pathology, postoperative infection risk, improvements in postoperative rehabilitation metrics, enhancement of osseous healing, and increased bone-implant integration. The authors suggest future areas of investigation that may provide guidance on how surgeons can mitigate adverse risks while optimizing benefits of TRT in the orthopaedic patient.

Pain mechanisms in the transgender individual: a review

Specific Aim

Provide an overview of the literature addressing major areas pertinent to pain in transgender persons and to identify areas of primary relevance for future research.

Methods

A team of scholars that have previously published on different areas of related research met periodically though zoom conferencing between April 2021 and February 2023 to discuss relevant literature with the goal of providing an overview on the incidence, phenotype, and mechanisms of pain in transgender patients. Review sections were written after gathering information from systematic literature searches of published or publicly available electronic literature to be compiled for publication as part of a topical series on gender and pain in the Frontiers in Pain Research.

Results

While transgender individuals represent a significant and increasingly visible component of the population, many researchers and clinicians are not well informed about the diversity in gender identity, physiology, hormonal status, and gender-affirming medical procedures utilized by transgender and other gender diverse patients. Transgender and cisgender people present with many of the same medical concerns, but research and treatment of these medical needs must reflect an appreciation of how differences in sex, gender, gender-affirming medical procedures, and minoritized status impact pain.

Conclusions

While significant advances have occurred in our appreciation of pain, the review indicates the need to support more targeted research on treatment and prevention of pain in transgender individuals. This is particularly relevant both for gender-affirming medical interventions and related medical care. Of particular importance is the need for large long-term follow-up studies to ascertain best practices for such procedures. A multi-disciplinary approach with personalized interventions is of particular importance to move forward.

Impact of continuous testosterone exposure on reproductive physiology, activity, and pain-related behavior in young adult female rats

Testosterone may reduce pain in cisgender women and transgender men. Rodents can provide a useful model for investigating physiological effects of hormone therapy. To this end, continuous-release testosterone or blank (placebo) capsules were implanted s.c. into young adult female rats, and three weeks later rats were either ovariectomized or sham-ovariectomized. Testosterone treatment that mimicked previously reported endogenous levels in males eliminated estrous cycling and decreased uterine weight. Testosterone also significantly increased body weight and suppressed the increases in daily wheel running observed in placebo controls over time. Subsequent ovariectomy or sham-ovariectomy decreased wheel running in all groups, but testosterone-treated rats recovered significantly more quickly than did placebo-treated rats. Neither testosterone nor ovariectomy significantly altered hindpaw mechanical threshold. Two weeks after sham/ovariectomy surgery, injection of Complete Freund Adjuvant (CFA) into one hindpaw reduced wheel running and mechanical threshold in all groups; running significantly decreased from the first to second day after CFA in testosterone- but not in placebo-treated rats. Morphine 1.0 but not 3.2 mg/kg increased CFA-suppressed wheel running similarly in all groups, whereas both doses of morphine increased CFA-suppressed mechanical threshold. These data suggest that weeks-long testosterone treatment with or without ovariectomy may provide a useful physiological model of testosterone therapy as used in human gender transition. Although testosterone administered at levels similar to those in gonadally intact males tended to hasten female rats' recovery from surgery, it did not decrease maximal pain-related behaviors after surgery or hindpaw inflammatory insult, nor did it alter opioid antinociception.

Lower serum testosterone is associated with increased likelihood of arthritis

Studies have suggested that serum testosterone levels may be strongly correlated with the pathogenesis of arthritis. Therefore, the aim of this study was to assess the relationship between serum testosterone levels and arthritis in US adults using the National Health and Nutrition Examination Survey (NHANES). We used the database from NHANES, 2013-2016 to perform a cross-sectional study. This study investigated the relationship between serum testosterone and arthritis using multivariate logistic regression models and also used smoothed curve fitting and generalized additivity models. A total of 10,439 adults were included in this analysis. A significant negative association between serum testosterone and arthritis was found in a linear regression analysis. The study showed that the arthritis group had lower testosterone levels than the non-arthritis group. The univariate multivariate analyses of Q4, using Q1 as a reference, all showed a significantly lower risk of developing arthritis. In subgroup analyses, the negative correlation between serum testosterone levels and arthritis was more significant in women and those with a body mass index (BMI) ≥ 30 kg/m2. After controlling for various variables, we found a significant association between serum testosterone and arthritis in this analysis. Further study of the relationship between testosterone and arthritis is necessary to clarify the specific mechanism of serum testosterone action on arthritis.

Associations Among Knee Osteoarthritis Severity, Body Mass Index, and Physical Functions in Saudi Arabian Adults: A Multi-Center Cross-Sectional Study

Background The purpose of this study was to investigate the associations among knee osteoarthritis severity, body mass index, and physical functions in Saudi Arabian adults. Methodology In this multi-center, cross-sectional study, we performed a secondary data analysis that included 189 adults aged 55 years or above with doctor-diagnosed knee osteoarthritis enrolled in five hospitals in Riyadh, Saudi Arabia, between March 2016 and March 2017. According to knee osteoarthritis severity, all of the individuals were divided into the following three groups: mild (n = 36), moderate (n = 75), and severe (n = 78). A high body mass index was defined as a body mass index score of >25 kg/m2. Physical function was evaluated using the 36-item physical functioning subscale. Results Severe knee osteoarthritis had a significantly 6.47-fold (95% confidence interval (CI) = 2.95-14.22, p < 0.0001) higher risk of physical function than those with mild knee osteoarthritis after adjusting for age, sex, educational status, occupational status, affected knee with osteoarthritis, knee pain, and body mass index. However, moderate knee osteoarthritis had a 1.22-fold higher risk of physical function, but the association was not statistically significant (95% CI = 0.60-2.49, p = 0.578). Conclusions Severe but not moderate knee osteoarthritis was more likely to have the worst physical function than mild knee osteoarthritis among adults with a high body mass index in Saudi Arabia.

Sex-dependent variation in cartilage adaptation: from degeneration to regeneration

Despite acknowledgement in the scientific community of sex-based differences in cartilage biology, the implications for study design remain unclear, with many studies continuing to arbitrarily assign demographics. Clinically, it has been well-established that males and females differ in cartilage degeneration, and accumulating evidence points to the importance of sex differences in the field of cartilage repair. However, a comprehensive review of the mechanisms behind this trend and the influence of sex on cartilage regeneration has not yet been presented. This paper aims to summarize current findings regarding sex-dependent variation in knee anatomy, sex hormones' effect on cartilage, and cartilaginous degeneration and regeneration, with a focus on stem cell therapies. Findings suggest that the stem cells themselves, as well as their surrounding microenvironment, contribute to sex-based differences. Accordingly, this paper underscores the contribution of both stem cell donor and recipient sex to sex-related differences in treatment efficacy. Cartilage regeneration is a field that needs more research to optimize strategies for better clinical results; taking sex into account could be a big factor in developing more effective and personalized treatments. The compilation of this information emphasizes the importance of investing further research in sex differences in cartilage biology.

Gender-Related Aspects in Osteoarthritis Development and Progression: A Review

Osteoarthritis (OA) is a common degenerative joint disease treated mostly symptomatically before approaching its definitive treatment, joint arthroplasty. The rapidly growing prevalence of OA highlights the urgent need for a more efficient treatment strategy and boosts research into the mechanisms of OA incidence and progression. As a multifactorial disease, many aspects have been investigated as contributors to OA onset and progression. Differences in gender appear to play a role in the natural history of the disease, since female sex is known to increase the susceptibility to its development. The aim of the present review is to investigate the cues associated with gender by analyzing various hormonal, anatomical, molecular, and biomechanical parameters, as well as their differences between sexes. Our findings reveal the possible implications of gender in OA onset and progression and provide evidence for gaps in the current state of art, thus suggesting future research directions.

Protection against Osteoarthritis Symptoms by Aerobic Exercise with a High-Protein Diet by Reducing Inflammation in a Testosterone-Deficient Animal Model

A testosterone deficiency potentially increases osteoarthritis (OA) symptoms, and dietary protein and exercise affect them. However, their efficacy and their interactions are still unclear. We hypothesized that a high-protein diet (HPD) and regular exercise modulated OA symptoms in testosterone-deficient rats, and it was examined in bilateral orchidectomized (ORX) and monoiodoacetate (MIA)-injected rats. The ORX rats were given a 30 energy percent (En%) protein (HPD) or 17.5 En% protein (CD). Both groups had 39 En% fat in the diet. Non-ORX-CD rats (sham-operation of ORX) were given the CD and no exercise (normal control). After an eight-week intervention, all rats had an injection of MIA into the left knee, and the treatments were continued for an additional four weeks. The non-ORX-CD rats showed a significant increase in body weight compared to the ORX rats, but the ORX rats had elevated fat mass. ORX exacerbated the glucose tolerance by lowering the serum insulin concentrations and increasing insulin resistance. ORX exacerbated the OA symptoms more than the non-ORX-CD. The HPD and exercise improved bone mineral density and glucose metabolism without changing serum testosterone concentrations, while only exercise increased the lean body mass and decreased fat mass, lipid peroxide, and inflammation. Exercise, but not HPD, reduced the OA symptoms, the weight distribution in the left leg, and running velocity and provided better relief than the non-ORX-CD rats. Exercise with HPD improved the histology of the knee joint in the left leg. Exercise reduced lipid peroxide contents and TNF-α and IL-1β mRNA expression in the articular cartilage, while exercise with HPD decreased MMP-3 and MMP-13 mRNA expression as much as in the non-ORX-CD group. In conclusion, moderate aerobic exercise with HPD alleviated OA symptoms and articular cartilage degradation in a similar way in the non-ORX rats with OA by alleviating inflammation and oxidative stress.

Targeting Soluble Epoxide Hydrolase and Cyclooxygenases Enhance Joint Pain Control, Stimulate Collagen Synthesis, and Protect Chondrocytes From Cytokine-Induced Apoptosis

Objective: To determine the symptomatic and disease-modifying capabilities of sEH and COX inhibitors during joint inflammation. Methods: Using a blinded, randomized, crossover experimental design, 6 adult healthy horses were injected with lipopolysaccharide (LPS; 3 μg) from E. coli in a radiocarpal joint and concurrently received the non-selective cyclooxygenase (COX) inhibitor phenylbutazone (2 mg/kg), the sEH inhibitor t-TUCB (1 mg/kg) or both (2 mg/kg phenylbutazone and 0.1, 0.3, and 1 mg/kg t-TUCB) intravenously. There were at least 30 days washout between treatments. Joint pain (assessed via inertial sensors and peak vertical forces), synovial fluid concentrations of prostanoids (PGE₂, TxB₂), cytokines (IL-1β, IL-6, TNF-α) and biomarkers of collagen synthesis (CPII) and degradation (C2C) were measured at pre-determined intervals over a 48-h period. The anti-apoptotic effect of COX and sEH inhibitors was determined via ELISA technique in primary equine chondrocytes incubated with TNF-α (10 ng/ml) for 24 h. Apoptosis was also determined in chondrocytes incubated with sEH-generated metabolites. Results: Combined COX and sEH inhibition produced significantly better control of joint pain, prostanoid responses, and collagen synthesis-degradation balance compared to each compound separately. When administered separately, pain control was superior with COX vs. sEH inhibition. Cytokine responses were not different during COX and/or sEH inhibition. In cultured chondrocytes, sEH inhibition alone or combined with COX inhibition, but not COX inhibition alone had significant anti-apoptotic effects. However, sEH-generated metabolites caused concentration-dependent apoptosis. Conclusions: Combined COX and sEH inhibition optimize pain control, attenuate loss of articular cartilage matrix during joint inflammation and cytokine-induced chondrocyte apoptosis.

The anatomy of pain and suffering in the brain and its clinical implications

Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage. Chronic pain, with a prevalence of 20-30 % is the major cause of human suffering worldwide, because effective, specific and safe therapies have yet to be developed. It is unevenly distributed among sexes, with women experiencing more pain and suffering. Chronic pain can be anatomically and phenomenologically dissected into three separable but interacting pathways, a lateral 'painfulness' pathway, a medial 'suffering' pathway and a descending pain inhibitory pathway. One may have pain(fullness) without suffering and suffering without pain(fullness). Pain sensation leads to suffering via a cognitive, emotional and autonomic processing, and is expressed as anger, fear, frustration, anxiety and depression. The medial pathway overlaps with the salience and stress networks, explaining that behavioural relevance or meaning determines the suffering associated with painfulness. Genetic and epigenetic influences trigger chronic neuroinflammatory changes which are involved in transitioning from acute to chronic pain. Based on the concept of the Bayesian brain, pain (and suffering) can be regarded as the consequence of an imbalance between the two ascending and the descending pain inhibitory pathways under control of the reward system. The therapeutic clinical implications of this simple pain model are obvious. After categorizing the working mechanisms of each of the available treatments (pain killers, psychopharmacology, psychotherapy, neuromodulation, psychosurgery, spinal cord stimulation) to 1 or more of the 3 pathways, a rational combination can be proposed of activating the descending pain inhibitory pathway in combination with inhibition of the medial and lateral pathway, so as to rebalance the pain (and suffering) pathways.

Sex Steroids and Osteoarthritis: A Mendelian Randomization Study

Objective

Sex steroids are thought to contribute to the pathogenesis of osteoarthritis (OA). This study investigated the causal role of sex steroids in site- and sex-specific OA and risk of joint replacement surgery using the Mendelian randomization (MR) method.

Methods

Instrumental variables for estradiol, dehydroepiandrosterone sulfate, testosterone (T), and dihydrotestosterone (DHT) were selected. We used the inverse variance weighting (IVW) approach as the main MR method to estimate causal effects based on the summary-level data for OA and joint replacement surgery from genome-wide association studies (GWAS).

Results

A positive causal association was observed between serum T level and risks of hip OA (odds ratio [OR]=1.558, 95% confidence interval [CI]: 1.193-2.034; P=0.001) and hip replacement (OR=1.013, 95% CI: 1.008-1.018; P=2.15×10-8). Serum DHT level was also positively associated with the risk of hip replacement (OR=1.011, 95% CI: 1.006-1.015; P=4.03×10-7) and had potential causality with hip OA (OR=1.398, 95% CI: 1.054-1.855; P=0.020).

Conclusions

Serum T and DHT levels may play causal roles in the development of hip OA and contribute to the risk of hip replacement, although the underlying mechanisms require further investigation.

Aqueous Extracts of Morus alba Root Bark and Cornus officinalis Fruit Protect against Osteoarthritis Symptoms in Testosterone-Deficient and Osteoarthritis-Induced Rats

Water extracts of both Morus alba L. root bark (MBW) and Cornus officinalis Siebold and Zucc fruit (CFW) have traditionally been used to promote men's health in the elderly in Asia. We determined that the 12-week consumption of MBW and CFW could alleviate testosterone-deficiency syndrome and osteoarthritis (OA) symptoms in testosterone-deficient rats, and the action mechanisms were explored. Rats with bilateral orchiectomy (ORX) were fed a 45% fat diet containing either 0.5% MBW (ORX-MBW), 0.5% CFW(ORX-CFW), or 0.5% dextrin (ORX-CON). Sham-operated rats also received 0.5% dextrin (Non-ORX-CON). After 8 weeks of treatment, all rats had an injection of monoiodoacetate (MIA) into the left knee, and they continued the same diet for the additional 4 weeks. ORX-CFW and ORX-MBW partially prevented the reduction of serum testosterone concentrations and decreased insulin resistance, compared to the ORX-CON. ORX-CFW and ORX-MBW protected against the reduction of bone mineral density (BMD) and lean body mass (LBM) compared to the ORX-CON. The limping and edema scores were lower in the order of the ORX-CON, ORX-CRF = ORX-MBW, and Non-ORX-CON (p < 0.05). The scores for pain behaviors, measured by weight-distribution on the OA leg and maximum running velocity on a treadmill, significantly decreased in the same order as limping scores. ORX-MBW protected against the increased expression of matrix metalloproteinase (MMP)-3 and MMP-13 and reduced the production of inflammatory markers such as TNF-α and IL-1β, by MIA in the articular cartilage, compared to the ORX-CON (p < 0.05). The cartilage damage near the tidemark of the knee and proteoglycan loss was significantly less in ORX-MBW than ORX-CON. In conclusion, MBW, possibly CFW, could be effective alternative therapeutic agents for preventing osteoarthritis in testosterone-deficient elderly men.