Homocysteine-lowering therapy or antioxidant therapy for bone loss in Parkinson's disease

B vitamins and bone health: a meta-analysis with trial sequential analysis of randomized controlled trials

Our study showed that B vitamins did not have significant effect on fracture incidence, bone mineral density, and bone turnover markers. However, the research data of B vitamins on bone mineral density and bone turnover markers are limited, and more clinical trials are needed to draw sufficient conclusions.

PURPOSE

The objective of this study was to identify the efficacy of B vitamin (VB) (folate, B6, and B12) supplements on fracture incidence, bone mineral density (BMD), and bone turnover markers (BTMs).

METHODS

A comprehensive search was performed in PubMed, MEDLINE, EMBASE, Cochrane databases, and ClinicalTrials.gov up to September 4, 2023. The risk of bias was assessed according to Cochrane Handbook and the quality of evidence was assessed according to the GRADE system. We used trial sequential analysis (TSA) to assess risk of random errors and Stata 14 to conduct sensitivity and publication bias analyses.

RESULTS

Data from 14 RCTs with 34,700 patients were extracted and analyzed. The results showed that VBs did not significantly reduce the fracture incidence (RR, 1.06; 95% CI, 0.95 - 1.18; p = 0.33; I2 = 40%) and did not affect BMD in lumbar spine and femur neck. VBs had no significant effect on bone specific alkaline phase (a biomarker for bone formation), but could increase the serum carboxy-terminal peptide (a biomarker for bone resorption) (p = 0.009; I2 = 0%). The TSA showed the results of VBs on BMD and BTMs may not be enough to draw sufficient conclusions due to the small number of sample data included and needed to be demonstrated in more clinical trials. The inability of VBs to reduce fracture incidence has been verified by TSA as sufficient. Sensitivity analysis and publication bias assessment proved that our meta-analysis results were stable and reliable, with no significant publication bias.

CONCLUSIONS

Available evidence from RCTs does not support VBs can effectively influence osteoporotic fracture risk, BMD, and BTMs.

TRIAL REGISTRATION

PROSPERO registration number: CRD42023427508.

Application of Antioxidant Compounds in Bone Defect Repair

Bone defects caused by trauma, tumor resection, and infections are significant clinical challenges. Excessive reactive oxygen species (ROS) usually accumulate in the defect area, which may impair the function of cells involved in bone formation, posing a serious challenge for bone repair. Due to the potent ROS scavenging ability, as well as potential anti-inflammatory and immunomodulatory activities, antioxidants play an indispensable role in the maintenance and protection of bone health and have gained increasing attention in recent years. This narrative review aims to give an overview of the main research directions on the application of antioxidant compounds in bone defect repair over the past decade. In addition, the positive effects of various antioxidants and their biomaterial delivery systems in bone repair are summarized to provide new insights for exploring antioxidant-based strategies for bone defect repair.

The Proper Diet and Regular Physical Activity Slow Down the Development of Parkinson Disease

From year to year, we know more about neurodegeneration and Parkinson’s disease (PD). A positive influence of various types of physical activity is more often described in the context of neuroprotection and prevention as well as the form of rehabilitation in Parkinson’s patients. Moreover, when we look at supplementation, clinical nutrition and dietetics, we will see that balancing consumed products and supplementing the vitamins or minerals is necessary. Considering the biochemical pathways in skeletal muscle, we may see that many researchers desire to identify molecular mediators that have an impact through exercise and balanced diet on human health or development of the neurodegenerative disease. Therefore, it is mandatory to study the potential mechanism(s) related to diet and factors resulted from physical activity as molecular mediators, which play a therapeutic role in PD. This review summarizes the available literature on mechanisms and specific pathways involved in diet-exercise relationship and discusses how therapy, including appropriate exercises and diet that influence molecular mediators, may significantly slow down the progress of neurodegenerative processes. We suggest that a proper diet combined with physical activity will be a good solution for psycho-muscle BALANCE not only in PD but also in other neurodegenerative diseases.

The association of homocysteine, folate, vitamin B12, and vitamin B6 with fracture incidence in older adults: a systematic review and meta-analysis

Background

Diverse conclusions have been drawn regarding the association of homocysteine (HCY) deficiency and supplements of B vitamins with fracture incidence in older adults. The aim of this meta-analysis was to investigate the association of HCY and B vitamins (folate, vitamin B12, and B6) with fracture incidence in older adults and whether supplements of B vitamins reduce the risk of fracture.

Methods

The PubMed, Embase, and Cochrane library databases were systematically searched from their inception dates to 1 July 2019 to identify relevant published articles. Meta-analysis was performed to pool hazard ratios (HRs) or risk ratios (RRs) and 95% confidence intervals (CIs) using a random effects model.

Results

A total of 28 studies fulfilled the inclusion criteria. High serum HCY was an independent risk factor for fractures in older persons (HR =1.25, 95% CI: 1.12 to 1.40), but only at the highest quartile level (>15 µmol/L) (HR =1.71, 95% CI: 1.37 to 2.12), rather than the second and third quartile. Multiple sensitivity and subgroup analyses supported the consistency and stability of this result. A severe deficiency of folate, instead of vitamin B12 and B6, was found to increase the risk of fracture in older adults (HR =1.46, 95% CI: 1.06 to 2.02; 1.24, 95% CI: 0.79 to 1.95; 1.36, 95% CI: 0.90 to 2.06, respectively). For the interventional effect, there was no significant association of combined folate and vitamin B12, combined folate, vitamin B12 and B6, or single vitamin B6 supplementation with the decrease of fracture risk.

Discussion

This meta-analysis revealed that significantly elevated serum level of HCY is positively associated with fracture incidence in older adults, yet the necessity and threshold for intervention by B vitamins require further large-scale high-quality clinical trials to validate.

PROSPERO identifier

CRD42019122586.

Osteoporosis in Parkinson's Disease: Relevance of Distal Radius Dual-Energy X-Ray Absorptiometry (DXA) and Sarcopenia

Osteoporotic fractures are common in Parkinson's disease (PD). Standard dual-energy X-ray absorptiometry (DXA) measuring bone mineral density (BMD) at the femoral neck and lumbar spine (central sites) has suboptimal sensitivity in predicting fracture risk in the general population. An association between sarcopenia and osteoporosis in PD has not been studied. We compared BMD and osteoporosis prevalence in PD patients vs controls; determined the osteoporosis detection rates using central alone vs central plus distal radius DXA; and analyzed factors (in particular, sarcopenia) associated with osteoporosis. One hundred and fifty-six subjects (102 patients with PD, 54 spousal/sibling controls) underwent femoral neck-lumbar spine-distal radius DXA. Seventy-three patients and 46 controls were assessed for sarcopenia using whole-body DXA and handgrip strength. Patients underwent clinical and serum biochemical evaluations. PD patients had significantly lower body mass index compared to controls. After adjustment for possible confounders, distal radius BMD and T-scores were significantly lower in PD patients compared to controls, but not at the femoral neck/lumbar spine. With distal radius DXA, an additional 11.0% of patients were diagnosed with osteoporosis (32.0% to 43.0%), vs 3.7% in controls (33.3% to 37.0%) additionally diagnosed; this increase was largely driven by the markedly higher detection rate in female PD patients. Female gender (adjusted odds ratio [OR_adjusted] = 11.3, 95% confidence interval [CI]: 2.6-48.6) and sarcopenia (OR_adjusted = 8.4, 95% CI: 1.1-64.9) were independent predictors for osteoporosis in PD. Distal radius DXA increased osteoporosis detection, especially in female PD patients, suggesting that diagnostic protocols for osteoporosis in PD could be optimized. A close association between osteoporosis and sarcopenia was documented for the first time in PD, which has important implications for clinical management and future research.

Dietary Approaches to Improve Efficacy and Control Side Effects of Levodopa Therapy in Parkinson's Disease: A Systematic Review

Although levodopa remains the most effective drug for symptomatic management of Parkinson's Disease (PD), treatment during advanced disease stages may raise unpredictable motor fluctuations and other complications. Counteracting these complications with other pharmacological therapies may prompt a vicious circle of side effects, and here, nutritional therapy may have great potential. Knowledge about the role of diet in PD is emerging and multiple studies have investigated nutritional support specifically with respect to levodopa therapy. With this systematic review, we aim to give a comprehensive overview of dietary approaches to optimize levodopa treatment in PD. A systematic search was performed using the databases of PubMed and Scopus between January 1985 and September 2020. Nutritional interventions with the rationale to optimize levodopa therapy in human PD patients were eligible for this study and their quality was assessed with the Cochrane risk-of-bias tool. In total, we included 22 papers that addressed the effects of dietary proteins (n = 10), vitamins (n = 7), fiber (n = 2), soybeans (n = 1), caffeine (n = 1), and ketogenic diets (n = 1) on levodopa therapy. Interventions with protein redistribution diets (PRDs), dietary fiber, vitamin C, and caffeine improved levodopa absorption, thereby enhancing clinical response and reducing motor fluctuations. Furthermore, supplementation of vitamin B-12, vitamin B-6, and folic acid successfully reduced high homocysteine concentrations that emerged from levodopa metabolism and promoted many metabolic and clinical complications, such as neuropathology and osteoporosis. In conclusion, dietary interventions have the potential to optimize levodopa efficacy and control side effects. Nutrition that improves levodopa absorption, including PRDs, fiber, vitamin C, and caffeine, is specifically recommended when fluctuating clinical responses appear. Supplements of vitamin B-12, vitamin B-6, and folic acid are advised along with levodopa initiation to attenuate hyperhomocysteinemia, and importantly, their potential to treat consequent metabolic and clinical complications warrants future research.

Causal effects of homocysteine levels on the changes of bone mineral density and risk for bone fracture: A two-sample mendelian randomization study

BACKGROUND & AIMS

Observational studies have demonstrated the relations of homocysteine (HCY) with bone mineral density (BMD) and bone fracture risk, but yielding contradictory results. The present study was conducted to evaluate whether the genetically predicted plasma HCY levels were causally associated with the change of BMD and the risk of bone fracture.

METHODS

Genetic summary statistics were extracted from genome-wide association study (GWAS) meta-analysis of plasma HCY levels (n = 44,147), GWAS meta-analyses of measured forearm (FA), femoral neck (FN) and lumbar spine (LS) BMD (n = up to 32,735), UK Biobank estimated heel BMD (eBMD) (n = 426,824) and fracture (n = 426,795) GWAS data. Two Sample Mendelian Randomization (TSMR) analysis was performed to assess the causal effects of genetically determined plasma HCY on the BMD and bone fractures.

RESULTS

The MR analysis indicated that, genetically decreased plasma HCY was associated with the increased FA-BMD based on the inverse variance weighting (IVW) method (standard deviation [SD] = 0.348, 95% CI: 0.146 to 0.550, P = 7 × 10^-4). However, there were no significant associations of genetically decreased plasma HCY with FN-BMD, LS-BMD, eBMD and the risk for bone fracture (SD = -0.041, 95% CI: -0.189 to 0.106, P = 0.582; SD = -0.053, 95% CI: -0.238 to 0.131, P = 0.572; SD = -0.030, 95% CI: -0.090 to 0.030, P = 0.328, odds ratio [OR]: 1.03, 95% CI: 0.94 to 1.13, P = 0.562, respectively). Moreover, the results also found that genetically determined HCY increase was not correlated with the changes of BMD and the risk for bone fracture.

CONCLUSION

Our study revealed that genetically decreased plasma HCY was associated with increase of FA-BMD.

Involvements of Hyperhomocysteinemia in Neurological Disorders

Homocysteine (HCY), a physiological amino acid formed when proteins break down, leads to a pathological condition called hyperhomocysteinemia (HHCY), when it is over a definite limit. It is well known that an increase in HCY levels in blood, can contribute to arterial damage and several cardiovascular disease, but the knowledge about the relationship between HCY and brain disorders is very poor. Recent studies demonstrated that an alteration in HCY metabolism or a deficiency in folate or vitamin B12 can cause altered methylation and/or redox potentials, that leads to a modification on calcium influx in cells, or into an accumulation in amyloid and/or tau protein involving a cascade of events that culminate in apoptosis, and, in the worst conditions, neuronal death. The present review will thus summarize how much is known about the possible role of HHCY in neurodegenerative disease.

Alpha-lipoic acid supplementation significantly reduces the risk of obesity in an updated systematic review and dose response meta-analysis of randomised placebo-controlled clinical trials

BACKGROUND

There are numerous trials reported the effect of alpha-lipoic acid (ALA) on obesity measurements; while no summarised dose-response meta-analysis is available to address the effects of dose and duration of ALA supplementation on obesity measurements. We aimed to summarise the results of studies evaluating the effects of ALA supplementation on obesity measurements in a systematic review and dose-response meta-analysis.

METHODS AND MATERIALS

In a systematic search from Scopus, PubMed, Embase, Proquest electronic databases up to January 2020 relevant studies were retrieved. Randomised, placebo-controlled trials investigating the effect of ALA supplementation on obesity measurements including weight, body mass index (BMI), waist circumference (WC), waist to hip ratio (WHR) and fat mass (FM) were included. Two class and dose-response meta-analysis were performed to data analysis.

RESULTS

Totally, 18, 21 and 8 studies were included for the meta-analysis of ALA-weight, ALA-BMI, ALA-WC, respectively. In the two-class meta-analysis, ALA treatment significantly reduced weight (WMD: -2.29 kg, 95% CI: -2.98, 1.60, P < .01) and BMI (WMD: -0.49 kg/m² , 95% CI:-0.83,-0.15, P = .005) but no effect on WC (WMD: -2.57 cm, 95% CI: -8.91, 3.76; P = .426). While the dose-response meta-analysis revealed that the duration of ALA treatment is a significant factor affecting WC reduction (P_{non-linearity}  = .047). While no evidence of departure from linearity was observed for other variables; moreover, subgrouping also revealed that gender could be an important factor affecting the ALA impact on WC which was significant among women (WMD: -4.099; CI: -7.837, -0.361; P = .032).

CONCLUSION

According to our finding, ALA treatment significantly reduced BMI, weight in a two-class meta-analysis without evidence of departure from linearity in terms of dose or duration. While the association of ALA treatment on WC is dependent to the duration of the study. Although further trials evaluating the other obesity measurements specially central obesity will be helpful to infer a more reliable result.

Emerging role of alpha-lipoic acid in the prevention and treatment of bone loss

Osteoporosis is a chronic disease associated with decreased bone density that afflicts millions of people worldwide. Current pharmacological treatments are limited, costly, and linked to several negative side effects. These factors are driving current interest in the clinical use of naturally occurring bioactive compounds to mitigate bone loss. Alpha-lipoic acid, a potent antioxidant and essential member of mitochondrial dehydrogenases, has shown considerable promise as an antiosteoclastogenic agent due to its potent reactive oxygen species-scavenging capabilities along with a proven clinical safety record. Collectively, current data indicate that alpha-lipoic acid protects from bone loss via a 2-pronged mechanism involving inhibition of osteoclastogenic reactive oxygen species generation and upregulation of redox gene expression.

HYPERHOMOCYSTEINEMIA AND ITS TREATMENT IN PATIENTS WITH PARKINSON'S DISEASE

Introduction:

Homocysteine is process-product of methionine demethylation. It has proatherogenic, prothrombotic, prooxidative, proapoptotic, osteoporotic, neurotoxic, neuroinflamatory, and neurodegenerative effects. Hyperhomocysteinemia correlates with C667T MTHFR mutation, decrease of folic acid and vitamin B, as well as prolonged use of certain medications.

Materials and Methods:

We measured levels of homocysteine in thirty patients (15::15) with “de novo” Parkinson’s disease, with average age 64.17 ± 13.19 (28-82) years (Department of Neurology, University Clinical Center Tuzla). Normal level of homocysteine for women was 3.36-20.44 micromole/l and 5.9-16 micromole/l for men. We followed the effects of medicament approach (folic acid) every six months for next five years.

Results:

20% of patients with “de novo” Parkinson’s disease exhibited hyperhomocysteinemia. An average level of homocysteine was 13.85 ± 5.82 micromole/l. Differences due to age and homocysteine levels, regardless of sex, were not concluded. For the next five years intake of folic acid (periodically, 1-2 months, 5 mg per day, orally) was effective to normalized levels of homocysteine in all.

Conclusion:

Hyperhomocysteinemia is present in every fifth patient with “de novo” Parkinson’s disease. Folic acid is medication of choice in treatment of hyperhomocysteinemia coexisting with Parkinson’s disease.

17β-estradiol attenuates homocysteine-induced oxidative stress and inflammatory response as well as MAPKs cascade via activating PI3-K/Akt signal transduction pathway in Raw 264.7 cells

Oxidative stress, inflammatory response, and mitogen-activated protein kinases (MAPKs) cascade are significant pathogenic factors of osteoporosis. It has been reported that elevated homocysteine (Hcy) may activate oxidative stress and reduce bone mineral density in post-menopausal osteoporosis. Moreover, hormone replacement therapy has been widely used in clinic to prevent and treat post-menopausal women with osteoporosis and osteoporotic fracture, but the molecular mechanisms and relevant signal transduction pathways underlying the action of Hcy remain unclear. In this study, we investigated the effects of 17β-estradiol (17β-E2) on the Hcy-induced oxidative stress, inflammatory response and MAPKs cascade, as well as the underlying signal transduction pathway in murine Raw 264.7 cells. The reactive oxygen species (ROS) was assessed by fluorospectrophotometry. The proinflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin (IL)-1β were analyzed by double-immunofluorescence labeling and reverse transcriptase polymerase chain reaction assay, respectively. Furthermore, phosphorylation levels of MAPKs cascade were measured by western blot analysis. A specific phosphatidylinositol 3-kinase (PI3-K) inhibitor, Wortmannin (1 μM) was employed to determine whether PI3-K/Akt signaling pathway mediated the 17β-E2's effect on Raw 264.7 cells. 17β-E2 markedly decreased the ROS production induced by Hcy, the expression of TNF-α and IL-1β at protein and mRNA levels, and down-regulated the phosphorylation of MAPKs (ERK1/2, JNK and p38). These suppressing effects of 17β-E2 on Hcy-induced changes were reversed by pretreatment with PI3-K inhibitor Wortmannin. The results indicate that 17β-estradiol may attenuate Hcy-induced oxidative stress, inflammatory response and up-regulation of MAPKs in Raw 264.7 cells via PI3-K/Akt signal transduction pathway.

Current experience in testing mitochondrial nutrients in disorders featuring oxidative stress and mitochondrial dysfunction: rational design of chemoprevention trials

An extensive number of pathologies are associated with mitochondrial dysfunction (MDF) and oxidative stress (OS). Thus, mitochondrial cofactors termed "mitochondrial nutrients" (MN), such as α-lipoic acid (ALA), Coenzyme Q10 (CoQ10), and l-carnitine (CARN) (or its derivatives) have been tested in a number of clinical trials, and this review is focused on the use of MN-based clinical trials. The papers reporting on MN-based clinical trials were retrieved in MedLine up to July 2014, and evaluated for the following endpoints: (a) treated diseases; (b) dosages, number of enrolled patients and duration of treatment; (c) trial success for each MN or MN combinations as reported by authors. The reports satisfying the above endpoints included total numbers of trials and frequencies of randomized, controlled studies, i.e., 81 trials testing ALA, 107 reports testing CoQ10, and 74 reports testing CARN, while only 7 reports were retrieved testing double MN associations, while no report was found testing a triple MN combination. A total of 28 reports tested MN associations with "classical" antioxidants, such as antioxidant nutrients or drugs. Combinations of MN showed better outcomes than individual MN, suggesting forthcoming clinical studies. The criteria in study design and monitoring MN-based clinical trials are discussed.

Homocysteine imbalance: a pathological metabolic marker

Perturbations in methyl group metabolism and homocysteine balance have emerged over the past few decades as having defining roles in a number of pathological conditions. Numerous nutritional, hormonal, and genetic factors that are characterized by elevations in circulating homocysteine concentrations are also associated with specific pathological conditions, including cancer development, autoimmune diseases, vascular dysfunction, and neurodegenerative disease. Although much remains to be explored, our understanding of the relationship between disease, methyl balance, and epigenetic control of gene expression has steadily progressed. However, homocysteine balance and its role in health and disease are not as clearly understood. This review presents our current understanding of homocysteine metabolism and its link to specific pathologies.

(-)-Epigallocathechin-3-gallate, an AMPK activator, decreases ovariectomy-induced bone loss by suppression of bone resorption

Previously, we showed that AMP-activated protein kinase (AMPK) negatively regulates receptor activator of nuclear factor-κB ligand-induced osteoclast formation in vitro. The present study investigated the effect of (-)-epigallocathechin-3-gallate (EGCG), an AMPK activator, on ovariectomy (OVX)-induced bone loss in mice. Female mice subjected to OVX were administered EGCG for 8 weeks. We measured total-body bone mineral density (BMD) before and after the operation at an interval of 4 weeks. We performed micro-computed tomography (micro-CT) of the tibia and bone histomorphometric examination of the femur. Western blot analysis was additionally performed, to detect levels of the phosphorylated and total forms of AMPK-α in calvarial extracts. EGCG prevented OVX-induced body weight gain. The OVX control did not show a significant increase in BMD values at baseline and after treatment, unlike the sham control. EGCG attenuated OVX-induced bone loss. Micro-CT experiments revealed that EGCG induced a significant increase in trabecular bone volume and trabecular number and a decrease in trabecular spacing compared to the OVX control. Histomorphometric analyses further showed that EGCG suppressed osteoclast surface and number. Phosphorylated AMPK expression was significantly elevated in bone following EGCG treatment. Our findings collectively indicate that EGCG decreases OVX-induced bone loss via inhibition of osteoclasts.