Serum Homocysteine, Folate, and Vitamin B12 Levels in Patients with Systemic Lupus Erythematosus: A Meta-Analysis and Meta-Regression

Association of c.+677 C>T (rs1801133) and c.+1298 A>C (rs1801131) MTHFR genetic variants with cardiometabolic and disease risk in systemic lupus erythematosus patients: A cross-sectional study

Systemic lupus erythematosus (SLE) patients present a high prevalence of cardiometabolic risk, associated with worse clinical manifestations and mortality. Folate, an essential micronutrient that participates in vital immune cellular functions, could positively affect the cardiometabolic and disease risk in SLE, through the methylenetetrahydrofolate reductase (MTHFR) enzyme, which participates in the folate metabolism, where single nucleotide variants (SNVs) have been described as a potential genetic risk factor for SLE. The aim of this study was to determine the association of the c.+677 C>T (rs1801133) and c.+1298 A>C (rs1801131) MTHFR genetic variants with cardiometabolic risk and clinical disease variables in SLE patients. A case-control study was conducted on 394 unrelated Mexican-mestizo women: 199 with SLE according to the 1997 SLE-ACR criteria and 196 control subjects (CS). Folic acid and homocysteine levels were evaluated by immunoassays. Genotyping of MTHFR genetic variants was carried out by allelic discrimination. No significant differences were found for folic acid (p = .15) and homocysteine serum levels (p = .59) between groups. According to the CC c.+677 MTHFR genotype, this was associated with low cardiovascular disease (CVD) risk by the Castelli index (OR = 0.42; p = .03) in SLE patients. The TC (OR = 1.3; p = .03) and the TA (OR = 1.6; p < .01) haplotypes from c.+677 C>T plus c.+1298 MTHFR were associated with SLE risk, while the CC MTHFR haplotype (OR = 0.5; p = .01) was found as a non-risk factor for the disease. In conclusion, the TC and the TA MTHFR haplotypes are associated with disease risk; meanwhile, the CC c.+677 MTHFR genotype confers lower cardiometabolic risk in Mexican-mestizo SLE patients.

Serum Uric Acid Combined with Homocysteine as a Predictive Biomarker of Lupus Nephritis

Serum uric acid (UA) and homocysteine (Hcy) are potential biomarkers of systemic lupus erythematosus (SLE). In this study, the expressions of UA and Hcy in SLE patients and the predictive value of these two parameters for lupus nephritis (LN) were studied. A total of 476 SLE patients were recruited to this case-control study, of which 176 SLE patients diagnosed with LN and 300 without LN. Serum UA and Hcy levels were analyzed. Multivariate logistic regression analysis was used to evaluate the relationship between serum UA and Hcy and LN. The receiver operating characteristic (ROC) curves were used to predict the role of combination of serum UA and Hcy in LN. We found that serum UA and Hcy levels in SLE patients with LN were significantly higher than those in controls (p<0.05). Multivariate logistic regressions showed that serum UA (OR+=+1.003, 95+% CI: 1.001-1.006, p+=+0.003), apolipoprotein B (Apo B) (OR+=+21.361, 95+% CI: 2.312-195.373, p+=+0.007) and Hcy (OR+=+1.042, 95+% CI: 1.011-1.080, p+=+0.014) were independent markers of LN. Combined serum UA and Hcy revealed a better result (AUC+=+0.718, 95+% CI: 0.670-0.676, p<0.001) in prediction of LN compared to that of the serum UA (AUC+=+0.710) and Hcy (AUC+=+0.657) independently. In conclusion, serum UA and Hcy could be predictive biomarkers of LN, and joint detection of serum UA and Hcy might be useful in the clinical setting.

Transcobalamin 2 orchestrates monocyte proliferation and TLR4-driven inflammation in systemic lupus erythematosus via folate one-carbon metabolism

Background

SLE is a complex autoimmune disease with deleterious effects on various organs. Accumulating evidence has shown abnormal vitamin B12 and one-carbon flux contribute to immune dysfunction. Transcobalamin II (TCN2) belongs to the vitamin B12-binding protein family responsible for the cellular uptake of vitamin B12. The role of TCN2 in SLE is still unclear.

Methods

We collected clinical information and blood from 51 patients with SLE and 28 healthy controls. RNA sequencing analysis, qPCR, and western blot confirmed the alteration of TCN2 in disease monocytes. The correlation between TCN2 expression and clinical features and serological abnormalities was analyzed. TCN2 heterozygous knockout THP1 cells were used to explore the effects of TCN2 dysfunction on monocytes. CCK-8 assay and EdU staining were used to detect cell proliferation. ELISA was conducted to assess vitamin B12, glutathione, and cytokines changes. UHPLC-MRM-MS/MS was used to detect changes in the intermediates of the one-carbon cycle. Flow cytometry is used to detect cell cycle, ROS, mitoROS, and CD14 changes.

Results

Elevated TCN2 in monocytes was correlated positively with disease progression and specific tissue injuries. Using CD14+ monocytes and TCN2 genetically modified THP1 cell lines, we found that the TCN2 was induced by LPS in serum from SLE patients. TCN2 heterozygous knockout inhibited cellular vitamin B12 uptake and one-carbon metabolism, leading to cell proliferation arrest and decreased Toll-like receptor 4 (TLR4)-mediated CCL2 release. Methionine cycle metabolites, s-adenosylmethionine and homocysteine, rescued these effects, whereas folate treatment proved to be ineffective. Folate deficiency also failed to replicate the impact of TCN2 downregulation on THP1 inflammatory response.

Conclusion

Our study elucidated the unique involvement of TCN2-driven one-carbon flux on SLE-associated monocyte behavior. Increased TCN2 may promote disease progression and tissue damage by enhancing one-carbon flux, fostering monocyte proliferation, and exacerbating TLR4 mediated inflammatory responses. The inhibition of TCN2 may be a promising therapeutic approach to ameliorate SLE.

Arterial thrombosis triggered by methotrexate-induced hyperhomocysteinemia in a systemic lupus erythematosus patient with antiphospholipid antibodies

Systemic lupus erythematosus (SLE) patients have an increased risk of cardiovascular disease and thrombotic events, and the presence of antiphospholipid antibodies further raises the risk of these complications. Here we report a case of a patient with SLE and triple positivity for antiphospholipid antibodies who developed a popliteal artery thrombosis in the context of a severe hyperhomocysteinemia after the introduction of methotrexate (MTX) treatment. MTX is one of the most prescribed medications for a wide spectrum of autoimmune diseases, including SLE. On the other hand, by interfering with folate metabolism, it may induce hyperhomocysteinemia, which, in turn, may increase the risk of vascular complications. Current recommendations suggest screening and, when possible, treating classical and disease-related cardiovascular risk factors in all lupus patients. Based on what observed in our case, we suggest a follow-up of homocysteine levels after the introduction of drugs capable of inducing hyperhomocysteinemia, such as MTX, in SLE patients at high cardiovascular risk.

Association Between Serum Thyroid Measurements and Hyperhomocysteinemia in Euthyroid Subjects: A Retrospective Cross-Sectional Study

Objective

The objective of this study was to investigate the association between serum thyroid measurements and homocysteine (HCy) in euthyroid participants.

Methods

This retrospective study was based on Hospital Information Systems. After excluding participants with thyroid dysfunction and those who had recently taken medications that affected serum HCy, 775 participants were enrolled. We compared the serum thyroid function measurements of patients with or without hyperhomocysteinemia (HHCy) and analyzed the effect of thyroid indicators on HHCy prevalence and HCy levels. Multivariate regression analysis was utilized to analyze the association of thyroid-stimulating hormone (TSH) and thyroid peroxidase (TPOAb) with HCy.

Results

The serum TSH level (2.10 ± 1.06 mIU/L) of HHCy patients (n = 98) was significantly higher than controls (n = 677) (1.65 ± 0.90 mIU/L) (p < 0.05), as was the positive rate of TPOAb (19.4% vs 10.0%, p < 0.05). The serum HCy levels in subjects with TSH within the highest quartile were significantly higher than those in the lowest quartile (13.49 ± 7.78 vs 9.81 ± 3.59 μmol/L, p < 0.05). HCy was also significantly higher in TPOAb-positive patients than in negative subjects (14.06 ± 8.89 vs 11.48 ± 5.47 μmol/L, p < 0.05). Among the TSH quartiles, the prevalence of HHCy showed a similar significant upward trend to that described above. The prevalence of HHCy was also significantly higher in TPOAb-positive patients. The results of multivariate regression analysis suggested that both TSH elevation and TPOAb positivity were independent risk factors for HCy elevation and HHCy prevalence. However, we found no definitive association between linear increases in TPOAb titers and HCy concentrations or HHCy prevalence.

Conclusion

Patients with HHCy had significantly higher TSH levels and positive rates of TPOAb. Elevated TSH and positive TPOAb levels were independent risk factors for elevated HCy concentrations and HHCy risk.

Genetically predicted levels of folate, vitamin B12, and risk of autoimmune diseases: A Mendelian randomization study

Background

Evidence from observational studies on the association of folate and vitamin B12 with autoimmune diseases are conflicting.

Objective

We aimed to investigate the relationship of folate and vitamin B12 with autoimmune diseases using Mendelian randomization (MR).

Materials and methods

We selected single-nucleotide polymorphisms associated with folate and vitamin B12 at the genome-wide significance level. Summary-level data for four common autoimmune diseases (vitiligo, inflammatory bowel disease, rheumatoid arthritis, and systemic lupus erythematosus) were obtained from large-scale genome-wide association studies, with a sample size of 44,266, 86,640, 58,284, and 23,210, respectively. MR analyses were conducted using the inverse variance weighted (IVW) approach, and sensitivity analyses were further performed to test the robustness.

Results

We found that a higher genetically determined serum folate level per one standard deviation (SD) was associated with a decreased risk of vitiligo by the IVW method [odds ratios (OR) = 0.47; 95% confidence interval (CI): 0.32–0.69; P = 1.33 × 10-4]. Sensitivity analyses using alternative methods showed similar associations, and no evidence of pleiotropy was detected by MR-Egger regression (P = 0.919). In addition, we observed that vitamin B12 per one SD was positively associated with IBD (IVW: OR = 1.14, 95% CI: 1.03–1.26, P = 0.010; maximum likelihood: OR = 1.14, 95% CI: 1.01–1.29, P = 0.035; MR-PRESSO: OR = 1.14, 95% CI:1.01–1.28, P =0.037), while the association was not significant after Bonferroni correction.

Conclusion

The study provides convincing evidence for an inverse association between serum folate level and risk of vitiligo. Further studies are warranted to elucidate the possible association between vitamin B12 and risk of IBD.

Study of common hypertriglyceridaemia genetic variants and subclinical atherosclerosis in a group of women with SLE and a control group

OBJECTIVE

SLE is associated with increased cardiovascular risk (CVR). High serum concentrations of triglyceride-rich lipoproteins and apolipoprotein B-rich particles constitute the characteristic dyslipidaemia of SLE.

METHODS

A cross-sectional study was conducted to study the relationship between genetic variants involved in polygenic hypertriglyceridaemia, subclinical atherosclerosis and lipoprotein abnormalities. 73 women with SLE and 73 control women age-matched with the case group were recruited (age range 30-75 years). Serum analysis, subclinical atherosclerosis screening studies for the detection of plaque, and genetic analysis of the APOE, ZPR1, APOA5 and GCKR genes were performed.

RESULTS

Triglyceride concentrations and the prevalence of hypertension, dyslipidaemia and carotid atherosclerosis were higher in women with SLE than in the control group. Multivariate logistic regression showed that CC homozygosity for the GCKR rs1260326 gene (OR=0.111, 95% CI 0.015 to 0.804, p=0.030) and an increase of 1 mmol/L in triglyceride concentrations were associated with a greater risk of carotid plaque in women with SLE (OR=7.576, 95% CI 2.415 to 23.767, p=0.001).

CONCLUSIONS

GCKR CC homozygosity (rs1260326) and serum triglyceride concentrations are independently associated with subclinical carotid atherosclerosis in women with SLE. Subclinical carotid atherosclerosis is also more prevalent in these women compared with the control group. The study of GCKR rs1260326 gene variants may contribute to more precise assessment of CVR and modulation of the intensity of lipid-lowering treatment in patients with SLE.

Safety assessment of HEA-enriched Cordyceps cicadae mycelia on the central nervous system (CNS), cardiovascular system, and respiratory system in ICR male mice

Cordyceps cicadae, an entomopathogenic fungus, is a source of traditional Chinese medicine in China. Due to the low yield of wild C. cicadae, artificial cultivation approaches will be needed to meet the increasing market demand. Using bioreactor culture can increase mass production and the abundance of the active component, N6-(2-hydroxyethyl)-adenosine (HEA). Here, we describe a safety assessment for a novel mycelium preparation method. Many studies have confirmed the safety of C. cicadae mycelia. However, the acute safety pharmacology of the C. cicadae enriched with the high HEA (3.90 mg/g) compound has not been evaluated. This study evaluated the central nervous system (CNS), cardiovascular system, and respiratory system in ICR male mice via oral gavage administration. For each requested item, two batches of eight mice tested on a vehicle (0.5% carboxymethyl cellulose, CMC) and C. cicadae mycelia (1,000 mg/kg) were performed. The heart rate at 60 min for the vehicle and C. cicadae mycelium treatment was 700.3 ± 55.4 and 603.0 ± 42.3 bpm, respectively (p = .4279). For echocardiographic analysis, the LV mass of the vehicle and drug treatment was 86.7 ± 6.4 and 80.2 ± 7.7, respectively (p = .0933). In the respiratory test, the tidal volume of the vehicle and drug treatments was 0.11 ± 0.01 and 0.14 ± 0.01 at 60 min, respectively (p = .4262). These results demonstrate that the oral administration of HEA-enriched C. cicadae mycelia is safe for the CNS, cardiovascular, and respiratory systems.

B Vitamins and One-Carbon Metabolism: Implications in Human Health and Disease

Vitamins B9 (folate) and B12 are essential water-soluble vitamins that play a crucial role in the maintenance of one-carbon metabolism: a set of interconnected biochemical pathways driven by folate and methionine to generate methyl groups for use in DNA synthesis, amino acid homeostasis, antioxidant generation, and epigenetic regulation. Dietary deficiencies in B9 and B12, or genetic polymorphisms that influence the activity of enzymes involved in the folate or methionine cycles, are known to cause developmental defects, impair cognitive function, or block normal blood production. Nutritional deficiencies have historically been treated with dietary supplementation or high-dose parenteral administration that can reverse symptoms in the majority of cases. Elevated levels of these vitamins have more recently been shown to correlate with immune dysfunction, cancer, and increased mortality. Therapies that specifically target one-carbon metabolism are therefore currently being explored for the treatment of immune disorders and cancer. In this review, we will highlight recent studies aimed at elucidating the role of folate, B12, and methionine in one-carbon metabolism during normal cellular processes and in the context of disease progression.