Can Glatiramer Acetate Prevent Cognitive Impairment by Modulating Oxidative Stress in Patients with Multiple Sclerosis?

Multiple sclerosis (MS) is an autoimmune disease characterized by demyelination and neuroinflammation, often accompanied by cognitive impairment. This study aims (1) to investigate the potential of glatiramer acetate (GA) as a therapy for preventing cognitive decline in patients with MS (pwMS) by modulating oxidative stress (OS) and (2) to seek out the differences in cognition between pwMS in a cohort exhibiting good clinical evolution and control subjects (CS). An exploratory, prospective, multicentre, cross-sectional case-control study was conducted, involving three groups at a 1:1:1 ratio-41 GA-treated pwMS, 42 untreated pwMS, and 42 CS. The participants performed a neuropsychological battery and underwent venepuncture for blood sampling. The inclusion criteria required an Expanded Disability Status Scale score of ≤3.0 and a minimum of 5 years of MS disease. Concerning cognition, the CS had a better performance than the pwMS (p = <0.0001), and between those treated and untreated with GA, no statistically significant differences were found. Regarding oxidation, no statistically significant differences were detected. Upon categorizing the pwMS into cognitively impaired and cognitively preserved groups, the lactate was elevated in the pwMS with cognitive preservation (p = 0.038). The pwMS exhibited a worse cognitive performance than the CS. The pwMS treated with GA did not show an improvement in oxidation. Lactate emerged as a potential biomarker for cognitive preservation.

Effects of Vortioxetine on Cognition and Fatigue in Patients with Multiple Sclerosis and Depression: A Case Series Study

INTRODUCTION

Vortioxetine is a multimodal antidepressant drug that has been reported to have a positive impact on cognition, social function, and fatigue. Nevertheless, it has not been widely studied. Our objective was to explore the effects of vortioxetine on these and other parameters in patients with multiple sclerosis (MS) and depression.

PATIENTS AND METHODOLOGY

This observational case series study included patients with MS and depression who received treatment with vortioxetine for at least 6 months. The patient history of depression and depressive symptoms was assessed. A neuropsychiatric evaluation was carried out using different scales, both before and after treatment.

RESULTS

Of the 25 patients who enrolled in the study, 17 completed the treatment. Significant improvements were observed in health status (EQ-5D; p = 0.002), mood (Beck's Depression Inventory, BDI-II; p = 0.006), anxiety (State-Trait Anxiety Inventory, STAI-State; p = 0.021, and STAI-Trait; p = 0.011), and in the general health test (Short Form Health Survey, SF-36) for the vitality (p = 0.028) and mental health (p = 0.025) domains of the patients who completed the treatment. However, no statistically significant differences were observed in the cognitive tests related to attention, information processing speed, or fatigue.

CONCLUSION

In this population, vortioxetine treatment was effective in reducing the symptoms of depression and improving anxiety, vitality, and mental health. In contrast, it did not produce any improvement in cognition or fatigue but an increase in sample size would be necessary to confirm these results.

Impairment of Mitochondrial Redox Status in Peripheral Lymphocytes of Multiple Sclerosis Patients

Literature suggests that oxidative stress (OS) may be involved in the pathogenesis of multiple sclerosis (MS), in which the immune system is known to play a key role. However, to date, the OS in peripheral lymphocytes and its contribution to the disease remain unknown. The aim of the present study was to explore the influence of OS in peripheral lymphocytes of MS patients. To that end, a cross-sectional, observational pilot study was conducted [n = 58: 34 MS and 24 healthy subjects (control group)]. We have measured superoxide production and protein mitochondrial complex levels in peripheral blood mononuclear cells (PBMCs) isolated from MS patients and control. Lactate levels and the antioxidant capacity were determined in plasma. We adjusted the comparisons between study groups by age, sex and cell count according to case. Results demonstrated that PBMCs, specifically T cells, from MS patients exhibited significantly increased superoxide anion production compared to control group (p = 0.027 and p = 0.041, respectively). Increased superoxide production in PBMCs was maintained after the adjustment (p = 0.044). Regarding mitochondrial proteins, we observe a significant decrease in the representative protein content of the mitochondrial respiratory chain complexes I-V in PBMCs of MS patients (p = 0.002, p = 0.037, p = 0.03, p = 0.044, and p = 0.051, respectively), which was maintained for complexes I, III, and V after the adjustment (p = 0.026; p = 0.033; p = 0.033, respectively). In MS patients, a trend toward increased plasma lactate concentration was detected [8.04 mg lactate/dL (5.25, 9.49) in the control group, 11.36 mg lactate/dL (5.41, 14.81) in MS patients] that was statistically significant after the adjustment (p = 0.013). This might be indicative of compromised mitochondrial function. Finally, antioxidant capacity was also decreased in plasma from MS patients, both before (p = 0.027) and after adjusting for sex and age (p = 0.006). Our findings demonstrate that PBMCs of MS patients show impaired mitochondrial redox status and deficient antioxidant capacity. These results demonstrate for the first time the existence of mitochondrial alterations in the cells immune cells of MS patients already at the peripheral level.

Lack of vitamin D receptor causes stress-induced premature senescence in vascular smooth muscle cells through enhanced local angiotensin-II signals

OBJECTIVES

The inhibition of the renal renin-angiotensin system by the active form of vitamin D contributes to the cardiovascular health benefits of a normal vitamin D status. Local production of angiotensin-II in the vascular wall is a potent mediator of oxidative stress, prompting premature senescence. Herein, our objective was to examine the impact of defective vitamin D signalling on local angiotensin-II levels and arterial health.

METHODS

Primary cultures of aortic vascular smooth muscle cells (VSMC) from wild-type and vitamin D receptor-knockout (VDRKO) mice were used for the assessment of cell growth, angiotensin-II and superoxide anion production and expression levels of cathepsin D, angiotensin-II type 1 receptor and p57(Kip2). The in vitro findings were confirmed histologically in aortas from wild-type and VDRKO mice.

RESULTS

VSMC from VDRKO mice produced more angiotensin-II in culture, and elicited higher levels of cathepsin D, an enzyme with renin-like activity, and angiotensin-II type 1 receptor, than wild-type mice. Accordingly, VDRKO VSMC showed higher intracellular superoxide anion production, which could be suppressed by cathepsin D, angiotensin-II type 1 receptor or NADPH oxidase antagonists. VDRKO cells presented higher levels of p57(Kip2), impaired proliferation and premature senescence, all of them blunted upon inhibition of angiotensin-II signalling. In vivo studies confirmed higher levels of cathepsin D, angiotensin-II type 1 receptor and p57(Kip2) in aortas from VDRKO mice.

CONCLUSION

The beneficial effects of active vitamin D in vascular health could be a result of the attenuation of local production of angiotensin-II and downstream free radicals, thus preventing the premature senescence of VSMC.

Beyond proteinuria: VDR activation reduces renal inflammation in experimental diabetic nephropathy

Local inflammation is thought to contribute to the progression of diabetic nephropathy. The vitamin D receptor (VDR) activator paricalcitol has an antiproteinuric effect in human diabetic nephropathy at high doses. We have explored potential anti-inflammatory effects of VDR activator doses that do not modulate proteinuria in an experimental model of diabetic nephropathy to gain insights into potential benefits of VDR activators in those patients whose proteinuria is not decreased by this therapy. The effect of calcitriol and paricalcitol on renal function, albuminuria, and renal inflammation was explored in a rat experimental model of diabetes induced by streptozotocin. Modulation of the expression of mediators of inflammation by these drugs was explored in cultured podocytes. At the doses used, neither calcitriol nor paricalcitol significantly modified renal function or reduced albuminuria in experimental diabetes. However, both drugs reduced the total kidney mRNA expression of IL-6, monocyte chemoattractant protein (MCP)-1, and IL-18. Immunohistochemistry showed that calcitriol and paricalcitol reduced MCP-1 and IL-6 in podocytes and tubular cells as well as glomerular infiltration by macrophages, glomerular cell NF-κB activation, apoptosis, and extracellular matrix deposition. In cultured podocytes, paricalcitol and calcitriol at concentrations in the physiological and clinically significant range prevented the increase in MCP-1, IL-6, renin, and fibronectin mRNA expression and the secretion of MCP-1 to the culture media induced by high glucose. In conclusion, in experimental diabetic nephropathy VDR activation has local renal anti-inflammatory effects that can be observed even when proteinuria is not decreased. This may be ascribed to decreased inflammatory responses of intrinsic renal cells, including podocytes, to high glucose.

Sustained activation of renal N-methyl-D-aspartate receptors decreases vitamin D synthesis: a possible role for glutamate on the onset of secondary HPT

N-methyl-D-aspartate (NMDA) receptors (NMDAR) are tetrameric amino acid receptors that act as membrane calcium channels. The presence of the receptor has been detected in the principal organs responsible for calcium homeostasis (kidney, bone, and parathyroid gland), pointing to a possible role in mineral metabolism. The aim of this study was to test the effect of NMDAR activation in the kidney and on 1,25(OH)₂D₃ synthesis. We determined the presence of NMDAR subunits in HK-2 (human kidney cells) cells and proved its functionality. NMDA treatment for 4 days induced a decrease in 1α-hydroxylase levels and 1,25(OH)₂D₃ synthesis through the activation of the MAPK/ERK pathway in HK-2 cells. In vivo administration of NMDA for 4 days also caused a decrease in blood 1,25(OH)₂D₃ levels in healthy animals and an increase in blood PTH levels. This increase in PTH induced a decrease in the urinary excretion of calcium and an increase in urinary excretion of phosphorous and sodium as well as in diuresis. Bone turnover markers also increased. Animals with 5/6 nephrectomy showed low levels of renal 1α-hydroxylase as well as high levels of renal glutamate compared with healthy animals. In conclusion, NMDAR activation in the kidney causes a decrease in 1,25(OH)₂D₃ synthesis, which induces an increase on PTH synthesis and release. In animals with chronic kidney disease, high renal levels of glutamate could be involved in the downregulation of 1α-hydroxylase expression.

RANKL increases vascular smooth muscle cell calcification through a RANK-BMP4-dependent pathway

Vascular calcification commonly associated with several pathologies and it has been suggested to be similar to bone mineralization. The axis RANKL-OPG (receptor activator of nuclear factor kappaB ligand-osteoprotegerin) finely controls bone turnover. RANKL has been suggested to increase vascular calcification, but direct evidence is missing. Thus, in the present work, we assess the effect of RANKL in vascular smooth muscle cell (VSMC) calcification. VSMCs incubated with RANKL showed a dose-dependent increase in calcification, which was abolished by coincubation with OPG. To test whether the effect was mediated by signaling to its receptor, knockdown of RANK was accomplished by short hairpin (sh)RNA. Indeed, cells lacking RANK showed no increases in vascular calcification when incubated with RANKL. To further elucidate the mechanism by which RANK activation increases calcification, we blocked both nuclear factor (NF)-kappaB activation pathways. Only IKKalpha inactivation inhibited calcification, pointing to an involvement of the alternative NF-kappaB activation pathway. Furthermore, RANKL addition increased bone morphogenetic protein (BMP)4 expression in VSMCs, and that increase disappeared in cells lacking RANK or IKKalpha. The increase in calcification was also blunted by Noggin, pointing to a mediation of BMP4 in the calcification induced by RANKL. Furthermore, in an in vivo model, the increase in vascular calcium content was parallel to an increase in RANKL and BMP4 expression, which was localized in calcified areas. However, blood levels of the ratio RANKL/OPG did not change. We conclude that RANKL increases vascular smooth muscle cell calcification by binding to RANK and increasing BMP4 production through activation of the alternative NF-kappaB pathway.

Vitamin D receptor levels in colorectal cancer. Possible role of BsmI polymorphism

A high expression of vitamin D receptor (VDR) in colorectal cancer (CRC) tumoral tissue has been related to a good prognosis and it has been proposed that it could be a good biological marker of CRC progression. Nevertheless, there are no previous studies that compare the VDR expression in tumoral towards normal tissue of the same CRC patient in relation to VDR BsmI genotype. We collected normal and tumoral tissue samples, as well as blood samples, from CRC patients (n=170) and controls (n=122). VDR genotyping was performed and BsmI homozygous patients were selected (CRC=50, Cont=32). VDR mRNA and protein levels were analyzed. We also measured 25-Hydroxyvitamin D serum levels. We found no differences in the polymorphism distribution in tumoral versus normal tissue (control: BB=15.7%, bb=41.3%, Bb=43%; CRC: BB=14.2%, bb=41.9%, Bb=43.9%). Furthermore, VDR levels decreased in colonic cancer tissue (mean: 3.03) versus normal mucosa (11.62) from the same patient (p<0.001), but this decrease was similar in both genotypes. There were differences in 25-Hydroxyvitamin D(3) levels between the CRC and the control group (CRC=8.65 ng/ml, Cont=18.15 ng/ml). In conclusion, we found a decrease in VDR levels in tumoral compared with normal mucosa from the same patient. This difference is independent of the BsmI polymorphism.