Circulating microRNAs as potential biomarkers for the identification of vascular dementia due to cerebral small vessel disease.

Background: the diagnosis of cerebral small vessel disease, a leading cause of vascular dementia (VaD), relies solely on neuroimaging studies. Circulating microRNAs (miRNAs) have been proposed as diagnostic biomarkers in various disorders. Our aim was to identify differentially expressed, circulating miRNAs in small vessel VaD which could serve as diagnostic biomarkers for this disease. Method: we performed plasma miRNA profiling by quantitative polymerase chain reaction (qPCR) array in small vessel VaD patients and age- and gender-matched, cognitively normal and healthy controls. Selected, differentially expressed miRNAs were validated by qPCR. Sensitivity, specificity and area under the curve (AUC) were calculated for each individual miRNA. Results: profiling results showed that 44 miRNAs were differentially expressed in small vessel VaD cases (P < 0.05 with a fold change of <2 or >2). A set of seven, highly differentially expressed miRNAs (fold change of <3.6 or >3.6), were estimated in a cohort of 204 small vessel VaD patients and 200 healthy, age and gender-matched controls. Validation study revealed that four miRNAs (miR-409-3p, miR-502-3p, miR-486-5p and miR-451a) could be used as valuable biomarkers for identifying the disease. Sensitivity, specificity and AUC for these miRNAs were 76, 75, 75  and 70%; 89, 89, 83 and 75% and 0.94, 0.92, 0.90 and 0.86, respectively. However, combined receiver operating characteristic curve analysis of seven miRNAs revealed an AUC of 0.64 with sensitivity of 55.5% and specificity of 65.7%. Conclusion: plasma miR-409-3p, miR-502-3p, miR-486-5p and miR-451a could be used to differentiate small vessel VaD patients from healthy controls. Large-scale studies of their biomarker potential are warranted.

Genetic variants of vitamin D receptor and susceptibility to ischemic stroke.

Vitamin D receptor (VDR) is a potential candidate for cardiovascular disease. To date the genetic association of VDR with ischemic stroke has not been explored. In the present study we aimed to evaluate the association between VDR gene variants and ischemic stroke in Asian Indian population. Overall, 557 subjects were investigated that included 313 ischemic stroke patients and 244 control subjects. Four single nucleotide polymorphisms of the VDR gene termed as Fok I, Apa I, Taq I and Bsm I were genotyped by using PCR-RFLP method. The genotype distribution of Bsm I polymorphism was found to deviate from the Hardy-Weinberg equilibrium in control subjects, and hence excluded from the study. Apa I and Taq I polymorphisms were not found to be associated with ischemic stroke. However, presence of ff genotype of Fok I was found to confer 2.97-fold risk of ischemic stroke (95% CI=1.16-7.63, P=0.02) as compared to FF genotype. This association was found to be independent of various demographic and important biochemical covariates including age, gender, smoking, alcohol intake, BMI, and serum glucose, lipid profile, insulin and HOMA-IR, 25-hydroxyvitamin D and plasma NOx levels [OR=2.27, 95% CI=1.25-4.09, P=0.01]. However, adjustment for lipid metabolites attenuated the genetic association [OR=1.68, 95% CI=0.75-3.78, P=0.21]. Fok I polymorphism was also found to be associated with total cholesterol levels; ff genotype carriers were found to have significantly higher cholesterol levels (203.56 ± 30.50mg/dl) as compared to FF carriers (177.38 ± 47.90 mg/dl) (P=0.04). On stratification by gender the genetic association between Fok I polymorphism and ischemic stroke remained significant in females only (OR=2.28, 95% CI=1.15-4.53, P=0.02). This genetic association was also found to attenuate on adjustment with lipid variables. In the present study we could associate the only known functional polymorphism of VDR i.e., Fok I, with ischemic stroke in a gender specific manner. Adjustment with lipid variables was found to attenuate this association indicating that impaired lipid metabolism may be the underlying mechanism of action of this polymorphism which leads to an increase in the risk of ischemic stroke. Further larger scale validations in other population are warranted in other population.

Low vitamin D status is associated with inflammatory response in older patients with cerebral small vessel disease.

OBJECTIVES: This study aimed to determine the association of the NF-κB inflammatory signaling pathway with vitamin D status in older cerebral small vessel disease (SVD) patients. METHODS: We measured serum 25(OH)D, pro-and anti-inflammatory cytokines, and mRNA levels of the vitamin D-activating enzyme, CYP27B1, as well as NF-kB, COX-2, the chemokine-CCL2, IL-1ß, IL-6, TNF-α, TGF-ß, and IL-10, in cerebral SVD patients aged ≥60 years presenting with vascular dementia and age and gender-matched healthy controls. RESULTS: Low vitamin D status (insufficiency: serum 25(OH)D 12-20 ng/ml; deficiency: ≤12 ng/ml) was more prevalent among patients compared to controls. The mRNA levels of NF-kB, COX-2, CCL2, IL-1ß, and IL-6, and serum levels of pro-inflammatory cytokines (IL-1α, IL-1ß, IL-6, and TNF-α) were significantly higher in cases compared to controls. There was a significant correlation between CYP27B1 and NF-kB, COX-2, CCL2, and IL-1ß gene expression. Serum IL-1α, IL-1ß, and IL-6 concentrations and the expression of CCL-2, NF-kB2, and NF-kB3 genes were higher in vitamin D-deficient subjects compared to vitamin D-sufficient subjects. There was a significant negative correlation between serum 25(OH)D and IL-1α, IL-6, and TNF-α, and a positive correlation between 25(OH)D and IL-10. CONCLUSION: Low vitamin D is associated with an inflammatory response via NF-kB signaling, which could play a role in the etio-pathogenesis of SVD. Further large-scale studies are required to validate our findings.

Vitamin D receptor (VDR) gene polymorphism and vascular dementia due to cerebral small vessel disease in an Asian Indian cohort.

Vitamin D receptor (VDR) and its ligand Vitamin D, play a crucial role in regulating multiple pathways for maintaining vascular health. The present study aimed at evaluating whether single nucleotide polymorphisms in VDR gene were associated with susceptibility to vascular dementia (VaD) due to cerebral small vessel disease (SVD). A total of 644 subjects (302 patients diagnosed with cerebral SVD-associated VaD and 342, age- and gender-matched healthy controls) were genotyped for VDR gene variants, FokI, ApaI, TaqI and BsmI, by PCR-RFLP method. Among the 4 examined VDR variants, the presence of the minor allele (Ff+ff vs FF) of FokI variant increased the risk for cerebral SVD by 1.5-fold in men (p = 0.047). Serum 25-hydroxyvitamin D [25(OH)D] was lower in subjects having the FokI "ff" genotype compared to those with the "FF" genotype (p = 0.044). Moreover, in subjects with low serum 25(OH)D the presence of "ff" genotype increased the odds of SVD by 2.5 folds (p = 0.041). ApaI polymorphism decreased the risk of cerebral SVD in women. The distribution of TaqI and BsmI variants were not significantly different between patients and controls. Further studies in large cohorts are necessary to validate the role of FokI polymorphism in cerebral SVD and VaD etiopathogenesis.

Clinical and Biochemical Outcomes Following EEG Neurofeedback Training in Traumatic Brain Injury in the Context of Spontaneous Recovery.

It has been found that reduction of posttraumatic stress symptoms is positively associated with the reduction of postconcussive symptoms. Cortisol is commonly used as a biomarker of stress. Understanding the role of posttraumatic stress and cortisol in symptom reduction has implication for neuropsychological rehabilitation particularly in the context of spontaneous recovery. OBJECTIVE: The aim of the research was to study the effectiveness of EEG neurofeedback training on clinical symptoms, perceived stress, and cortisol in traumatic brain injury (TBI) patients in the context of spontaneous recovery. METHODS: The design was an experimental longitudinal design with the pre-post comparison. The sample comprised 60 patients with the diagnosis of TBI-30 patients in the neurofeedback training (NFT) group and 30 patients in the treatment as usual group (TAU) group. Half of the patients were recruited within 6 months of injury to study the role of spontaneous recovery and the other half were recruited in the 12 to 18 months postinjury phase. Alpha-theta training was given to the NFT group over 20 sessions. Pre and post comparisons were made on clinical symptom rating, perceived stress, and serum cortisol levels. RESULTS: The results indicate significant differences in symptom reporting and perceived stress between the NFT and TAU groups. Significant differences were also seen in cortisol levels with implications for the acute recovery phase. CONCLUSION: Alpha-theta NFT has a beneficial effect on symptom reduction as well as perceived stress. It also has a beneficial effect on levels of serum cortisol, corroborating these findings.

Vitamin D status and vascular dementia due to cerebral small vessel disease in the elderly Asian Indian population.

Vitamin D plays vital roles in human health and recent studies have shown its beneficial effect on brain functioning. The present study was designed to evaluate the association of vitamin D with vascular dementia (VaD) due to cerebral small vessel disease (SVD) in Asian Indian population. 140 VaD patients aged ≥ 60 years with neuroimaging evidence of SVD, and 132 age and gender-matched controls, were investigated. Vitamin D status was estimated by measuring serum 25-hydroxy vitamin D. Logistic regression model revealed that deficient levels of vitamin D (<12 ng/ml) were associated with 2.2-fold increase in odds of VaD after adjustment with covariates. Hypertension was independently associated with 11.3-fold increased odds of VaD. In hypertensives with vitamin D deficiency and insufficiency (12-20 ng/ml), the odds were increased to 31.6-fold and 14.4-fold, respectively. However, in hypertensives with vitamin D sufficiency (>20 ng/ml), the odds of VaD were increased by 3.8-fold only. Pearson correlation showed that serum vitamin D was inversely associated with systolic and diastolic blood pressure (r=-0.401 and -0.411, p<0.01, respectively) in vitamin D-deficient subjects. Since the combined presence of hypertension and vitamin D deficiency increases the probability of developing VaD, screening for vitamin D status in addition to regular monitoring of blood pressure, could reduce the risk of VaD associated with cerebral SVD in the elderly Asian Indian subjects.

Angiotensin-converting enzyme gene insertion/deletion polymorphism and small vessel cerebral stroke in Indian population.

Background. Hypertension is an established risk factor for small-vessel cerebral stroke and the renin-angiotensin system plays an important role in the maintenance of blood pressure. We aimed at evaluating the contribution of the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism to the risk of small-vessel stroke in south Indian population. Materials and Methods. We investigated 128 patients diagnosed with small-vessel stroke and 236 age, and gender-matched healthy controls. ACE I/D polymorphism was detected by polymerase chain reaction. Results. Hypertension was significantly more prevalent in the patient group and was associated with 6-fold increase in risk for stroke. ACE genotypes were in Hardy-Weinberg equilibrium in both patients and controls. Prevalence of DD, ID, and II genotypes in cases (34.4%, 43.7%, and 28%) did not differ significantly from controls (31.8%, 43.2%, and 25%). The polymorphism was not associated with small-vessel stroke (OR: 1.34; 95% CI: 0.52-1.55). However, diastolic blood pressure was associated with the ACE I/D genotypes in the patients. (DD; 90.2 ± 14.2> ID; 86.2 ± 11.9> II; 82.3 ± 7.8 mm Hg, P = 0.047). Conclusion. Our study showed that hypertension, but not ACE I/D polymorphism, increased the risk of small-vessel stroke.

Janus kinase (JAK) 2 V617F mutation in Asian Indians with cerebral venous thrombosis and without overt myeloproliferative disorders.

It is unclear whether the somatic JAK2V617F mutation, a marker for chronic myeloproliferative disorders (MPDs), is associated with cerebral venous thrombosis (CVT) in the absence of MPD. Our aim was to determine the prevalence and association of the JAK2V617F mutation among patients with CVT and without overt MPD. We investigated 372 CVT patients without features suggestive of MPD and 383 age- and gender-matched healthy controls, for the JAK2V617F mutation. Genotyping was done by polymerase chain reaction and restriction fragment length polymorphism. The heterozygous JAK2V617F mutation was present in 22 of 372 patients (5.9%) and 2 of 383 controls (0.5%). Logistic regression analysis showed this mutation to be an independent predictor of CVT after adjusting for the conventional risk factors (adjusted odds ratio: 5.47, 95% CI: 1.06-28.27, p=0.04). The mutation was more prevalent in men (p=0.005). Patients with JAK2V617F mutation were older (p=0.036), and had higher mean hemoglobin level (p<0.0001) than those without the mutation. Smokers with the mutation had 9.45-fold increased risk of CVT compared to non-smokers without the mutation (OR: 9.45, 95% CI: 1.17-76.02, p<0.0001). We conclude that the JAK2V617F mutation could contribute to increased risk of CVT in Indians. Larger studies in other ethnic populations are warranted before considering the inclusion of the JAK2V617F gene polymorphism into the routine diagnostic workup of CVT.