Dietary antioxidants, non-enzymatic antioxidant capacity and the risk of osteoarthritis in the Swedish National March Cohort

Vitamin C intake and osteoarthritis: findings of NHANES 2003-2018 and Mendelian randomization study

Background

The role of vitamin C in osteoarthritis (OA) is still a subject of debate. Our aim was to combine the National Health and Nutrition Examination Survey (NHANES) and MR studies to explore the relationship between vitamin C intake and OA.

Methods

Clinical information on participants during NHANES 2003-2018 was collected and the relationship between vitamin C intake and OA risk was assessed using logistic regression modelling. In MR analyses, three methods were used to explore the causality of vitamin C intake with OA. Sensitivity analysis to verify the stability of the MR study.

Results

The cross-sectional study included a total of 31,527 participants, categorizing them into low (<30.2 mg), medium (30.2-93.0 mg) and high (>93.0 mg) level groups based on their vitamin C intake levels. Logistic regression models showed that vitamin C intake was not associated with OA risk (p > 0.05). Inverse-variance weighted (IVW) method of MR study showed no causality between vitamin C intake and OA (OR = 0.993, 95% CI: 0.901 ~ 1.095, p = 0.882). Sensitivity analysis indicated that the MR study was reliable.

Conclusion

Our cross-sectional and MR studies showed that vitamin C intake was not associated with OA risk. More researches are needed in the future to investigate the link between vitamin C and OA.

Environmental and Genetic Determinants of Ankylosing Spondylitis

Exposure to heavy metals and lifestyle factors like smoking contribute to the production of free oxygen radicals. This fact, combined with a lowered total antioxidant status, can induce even more damage in the development of ankylosing spondylitis (AS). Despite the fact that some researchers are looking for more genetic factors underlying AS, most studies focus on polymorphisms within the genes encoding the human leukocyte antigen (HLA) system. The biggest challenge is finding the effective treatment of the disease. Genetic factors and the influence of oxidative stress, mineral metabolism disorders, microbiota, and tobacco smoking seem to be of great importance for the development of AS. The data contained in this review constitute valuable information and encourage the initiation and development of research in this area, showing connections between inflammatory disorders leading to the pathogenesis of AS and selected environmental and genetic factors.

Dietary and serum antioxidant capacity is inversely associated with patients in osteoarthritis: a case-control study

This study aimed to examine dietary antioxidant and serum antioxidant capacity in patients with knee osteoarthritis (OA). This case-control study consisted of 47 patients with OA (case group) and 30 healthy subjects (control group). The control and case group were matched age, gender, and body mass index (p > 0.05). A food frequency questionnaire was administered to participants, and dietary total antioxidant capacity (DTAC) was estimated using the ferric reducing antioxidant power method (FRAP). Participants' serum total antioxidant capacity (TAC) and total oxidant capacity (TOC) measurements were performed, and the oxidative stress index (OSI) was calculated. DTAC of case group was found to be lower than the control group (p < 0.05). The daily consumption of red meat and butter of the individuals in the case group was higher than that of the control group, and their fish consumption, dietary vitamin A and carotene intakes were found to be lower (p < 0.05). In addition, OA patients have TAC and OSI was also found to be significantly higher than in control group (p = 0.001 and p < 0.001). Since low dietary total antioxidant capacity and high serum total oxidant capacity, individuals with OA should pay more attention to their diet to increase serum antioxidant status.

Genetic liability for diet-derived circulating antioxidants, oxidative stress, and risk of osteoarthritis: a Mendelian randomization study

Background

Although well-documented, the causal relationships between diet-derived circulating antioxidants, oxidative stress, and osteoarthritis (OA) are equivocal. The objective of this study is to employ two-sample Mendelian randomization (MR) to investigate possible causal relationships among dietary-derived circulating antioxidants, oxidative stress damage indicators, and OA risk.

Methods

Single-nucleotide polymorphisms for diet-derived circulating antioxidants (ascorbate, β-carotene, lycopene, retinol, and α-and γ-tocopherol), assessed as absolute levels and metabolites, as well as oxidative stress injury biomarkers (GSH, GPX, CAT, SOD, albumin, and total bilirubin), were retrieved from the published data and were used as genetic instrumental variables. Summary statistics for gene-OA associations were obtained from publicly available and two relatively large-scale GWAS meta-analyses to date. The inverse-variance weighting method was utilized as the primary MR analysis. Moreover, multivariable MR was used to determine if mediators (BMI and smoking) causally mediated any connection. Furthermore, for each exposure, MR analyses were conducted per outcome database and then meta-analyzed.

Results

Genetically predicted absolute retinol level was causally associated with hip OA risk [odds ratios (ORs) = 0.40, 95% confidence interval (CI) = 0.24-0.68, FDR-corrected p = 0.042]. Moreover, genetically predicted albumin level was causally associated with total OA risk (OR = 0.80, 95% CI = 0.75-0.86, FDR-corrected p = 2.20E-11), as well as the risk of hip OA (OR = 0.75, 95% CI = 0.68-0.84, FDR-corrected p = 1.38E-06) and knee OA (OR = 0.82, 95% CI = 0.76-0.89, FDR-corrected p = 4.49E-06). In addition, MVMR confirmed that the effect of albumin on hip OA is independent of smoking initiation, alcoholic drinks per week, and moderate-to-vigorous physical activity levels but may be influenced by BMI.

Conclusion

Evidence from our study supports a potentially protective effect of high levels of retinol and albumin on OA risk.

A standardized nutraceutical supplement contributes to pain relief, improves quality of life and regulates inflammation in knee osteoarthritis patients; A randomized clinical trial

Osteoarthritis (OA) is a degenerative disease of the joints that affects greatly the elderly population and the health care systems and is on the increase due to aging and obesity. Interventions aim at palliative care and pharmaceutical therapies entail serious adverse events. Whereas polyphenols constitute a promising holistic approach in the arsenal of physicians, trials investigating biomarkers and questionnaires are scarce. As such, a randomized controlled trial (RCT) was conducted to evaluate the potency of a standardized polyphenolic supplement in the management of systemic inflammation, oxidative stress, pain and general quality of life (QoL) in patients with osteoarthritis. Sixty subjects were randomized to receive either a polyphenol supplement (curcuma phospholipid, rosemary extract, resveratrol, ascorbic acid), or an active comparator (ascorbic acid) twice, daily for 12 weeks. The group that received the polyphenols exhibited significantly lower symptoms of pain and improved physical function and QoL as it was depicted by validated questionnaires, compared to the control group. Furthermore, post intervention, inflammation was restrained in the polyphenol group. Since systemic inflammation promotes local inflammation, the decrease of pain herein might be attributed to the attenuation of systemic inflammation by the polyphenols.

Lipid peroxidation in osteoarthritis: focusing on 4-hydroxynonenal, malondialdehyde, and ferroptosis

Osteoarthritis (OA) is a multifactorial and increasingly prevalent degenerative disease that affects the whole joint. The pathogenesis of OA is poorly understood and there is a lack of therapeutic interventions to reverse the pathological process of this disease. Accumulating studies have shown that the overproduction of reactive oxygen species (ROS) and ROS-induced lipid peroxidation are involved in the pathogenesis of OA. 4-Hydroxy-2-nonenal (4-HNE) and malondialdehyde (MDA) have received considerable attention for their role in cartilage degeneration and subchondral bone remodeling during OA development. Ferroptosis is a form of cell death characterized by a lack of control of membrane lipid peroxidation and recent studies have suggested that chondrocyte ferroptosis contributes to OA progression. In this review, we aim to discuss lipid peroxidation-derived 4-HNE and MDA in the progression of OA. In addition, the therapeutic potential for OA by controlling the accumulation of lipid peroxidation and inhibiting chondrocyte ferroptosis are discussed.

Diet-derived circulating antioxidants and risk of knee osteoarthritis, hip osteoarthritis and rheumatoid arthritis: a two-sample Mendelian randomization study

Objective

To examine the causal associations of diet-derived circulating antioxidants with knee osteoarthritis (OA), hip OA, and rheumatoid arthritis (RA) within the two-sample Mendelian randomization (MR) framework.

Method

Independent single-nucleotide polymorphisms (SNPs) significantly associated with circulating levels of diet-derived antioxidants (retinol, β-carotene, lycopene, vitamin C and vitamin E) were extracted as genetic instruments. Summary statistics of genetic instruments associated with knee OA, hip OA, and RA were obtained from corresponding genome-wide association studies (GWASs). The inverse-variance weighted (IVW) was applied as the primary analysis method, with four sensitivity analysis approaches employed to evaluate the robustness of the primary results.

Results

Genetically determined per unit increment of absolute circulating levels of retinol was significantly associated with a reduced risk of hip OA [odds ratio (OR) = 0.45, 95% confidence interval (CI) 0.26-0.78, p = 4.43 × 10^-3], while genetically determined per unit increase in absolute circulating levels of β-carotene was suggestively associated with increased risk of RA (OR = 1.32, 95% CI 1.07-1.62, p = 9.10 × 10^-3). No other causal association was found. Significant evidence for heterogeneity and pleiotropic outlier was only identified when absolute circulating vitamin C was evaluated as the exposure, whereas all sensitive analysis provided consistently non-significant results.

Conclusion

Our results demonstrated that genetically determined lifelong higher exposure to absolute circulating levels of retinol is associated with a decreased risk of hip OA. Further MR study with more genetic instruments for absolute circulating levels of antioxidants are needed to confirm our results.

Agreement Between Body Mass Index and Body Fat in Adolescents With Different Physical Activity Levels

Purpose: This study aimed to verify the agreement between body mass index (BMI) and body fat in adolescents with different physical activity (PA) levels. Method: This cross-sectional study collected body fat data in 118 adolescents (aged 10 to 14 years) estimated using air-displacement plethysmography (ADP). Body mass 10 and height were used to calculate BMI. Physical activity levels were measured objectively by accelerometers. Results: For boys with low PA, BMI overestimated body fat values measured by ADP (mean error = -0.42; p = .018) which also occurred in group high PA (mean error = -0.76; p = .001). For girls, BMI underestimated body fat values measured by ADP values in group high PA (mean error = 0.43; p = .001) and low PA (mean error = 0.72; p < .001). Conclusion: It is recommended that researchers and practitioners 15 cautiously interpret BMI results, especially considering that most adolescents do not practice enough PA.

Vitamin C supplementation for the treatment of osteoarthritis: perspectives on the past, present, and future

According to the US Centers for Disease Control and Prevention (CDC), an estimated 14% of adults in the United States have either been diagnosed with osteoarthritis (OA) or have symptoms suggestive of the disease. The CDC also points out that the incidence of OA has been gradually increasing over the past 30 years. What is more worrisome is that this trend is going to accelerate due to the aging demographics of the United States and the increasing prevalence of obesity seen in the country. The need for better preventive treatments and efficacious therapeutics are direly needed to combat this public health crisis. Among the possible treatments being hypothesized, antioxidant supplementation has become one of the most widely studied over the past decade due to its ability to attenuate reactive oxygen species (ROS) formation within chondrocytes, a critical step in the pathogenesis of this disease. Vitamin C has emerged as among the most promising of the antioxidant group, with many animal and human studies having been conducted in recent years. Although many of the studies have shown encouraging results in terms of preventing OA, others have reached opposite conclusions, thus making the data controversial. However, after reviewing several of these studies, we hypothesize that certain parameters may not have been properly considered during data collection. In the end, more randomized placebo-controlled trials in humans are desperately needed in order to fully understand whether vitamin C therapy is efficacious in treating and/or preventing OA.

Silymarin modulates catabolic cytokine expression through Sirt1 and SOX9 in human articular chondrocytes

Background

Silymarin (SMN), a polyphenolic flavonoid, is involved in multiple bioactive functions including anti-inflammation. Pretreatment with SMN demonstrated chondroprotection against tumour necrosis factor-alpha (TNF-α) stimulation in a chondrocyte cell line. However, pre- and posttreatment with phytochemicals have varying effects on osteoarthritis (OA) chondrocytes, and the therapeutic potential of SMN after catabolic cytokine stimulation is not fully elucidated.

Methods

The cytotoxicity of SMN (12.5, 25, 50 and 100 μM) was evaluated in human primary chondrocytes. The chondrocytes were supplemented with SMN (25 and 50 μM) after interleukin-1beta (IL-1β) stimulation. The mRNA expression and protein production of catabolic/anabolic cytokines as well as extracellular matrix (ECM) components were evaluated.

Results

High-dose SMN (100 μM) impaired the mitochondrial activity in chondrocytes, and 50 μM SMN further caused cell death in IL-1β-stimulated cells. The addition of 25 μM SMN ameliorated cell senescence; downregulated the catabolic genes of inducible nitric oxide synthase, IL-1β, TNF-α, matrix metalloproteinase-3 (MMP-3), MMP-9 and MMP-13; upregulated the anabolic genes of tissue inhibitor of metalloproteinase-1 (TIMP-1) and collagen type II alpha 1; and restored the expression of chondrogenic phenotype genes SOX9 and sirtuin-1 (Sirt1). In addition, the production of IL-1β, MMP-3 and MMP-9 decreased with an increase in TIMP-1 secretion. However, the mRNA levels of IL-6, IL-8 and IL-10 and protein production remained high. The addition of nicotinamide, a Sirt1 inhibitor, downregulated SOX9 and attenuated the therapeutic effects of SMN on IL-1β-stimulated chondrocytes.

Conclusion

SMN regulates the chondrocyte phenotype through Sirt1 and SOX9 to improve ECM homeostasis and may serve as a complementary therapy for early-stage knee OA.

Dietary Antioxidants and the Risk of Parkinson Disease: The Swedish National March Cohort

OBJECTIVE

To determine whether high baseline dietary antioxidants and total nonenzymatic antioxidant capacity (NEAC) is associated with a lower risk of Parkinson disease (PD) in men and women, we prospectively studied 43,865 men and women from a large Swedish cohort.

METHODS

In the Swedish National March Cohort, 43,865 men and women aged 18-94 years were followed through record linkages to National Health Registries from 1997 until 2016. Baseline dietary vitamin E, vitamin C, and beta-carotene intake, as well as NEAC, were assessed by a validated food frequency questionnaire collected at baseline. All exposure variables were adjusted for energy intake and categorized into tertiles. Multivariable Cox proportional hazard regression models were fitted to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) for PD.

RESULTS

After a mean follow-up time of 17.6 years, we detected 465 incidence cases of PD. In the multivariable adjusted model, dietary vitamin E (HR 0.68, 95% CI 0.52-0.90; p for trend 0.005) and vitamin C (HR 0.68, 95% CI 0.52-0.89; p for trend 0.004) were inversely associated with the risk of PD when comparing participants in the highest vs the lowest tertiles of exposure. No association was found with estimated intake of dietary beta-carotene or NEAC.

CONCLUSION

Our findings suggest that dietary vitamin E and C intake might be inversely associated with the risk of PD. No association was found with dietary beta-carotene or NEAC.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that dietary vitamin E and C intake are inversely associated with the risk of PD.