Homocysteine, vitamin determinants and neurological diseases.

This review focuses on the putative role of hyper-homocysteinemia in the pathogenesis of different diseases affecting the nervous system, including stroke, Alzheimer's disease, Parkinson's disease, epilepsy, multiple sclerosis and amyotrophic lateral sclerosis. However, a firm pathogenic role of homocysteine in these diseases has never been established. Lowering plasma homocysteine levels trough vitamin therapy failed to prevent vascular diseases. Conversely, normalization of hyper-homocysteinemia caused improvement in patients with cognitive impairment. B vitamin deficiency is the main determinant of homocysteine levels. However, it has been hypothesized that homocysteine might be a mere marker of vitamin deficiency or an indicator of disease rather than a risk factor. A more consistent use of thresholds to define deficiency is needed to recommend routine screening, monitoring and supplementation of B vitamins to ameliorate the prognosis of the above mentioned disorders. To date, data are insufficient to firmly establish which one of the hypotheses made is correct and the question concerning the real meaning of hyper-homocysteinemia in the pathology of the nervous system still remains an intriguing medical dilemma

NF-kappaB activation is associated with homocysteine-induced injury in Neuro2a cells

<p>Abstract</p> <p>Background</p> <p>Perinatal exposure to hyperhomocysteinemia might disturb neurogenesis during brain development and growth. Also, high levels of homocysteine trigger neurodegeneration in several experimental models. However, the putative mechanisms of homocysteine-induced toxicity in the developing nervous system have poorly been elucidated. This study was aimed to investigate homocysteine effects in undifferentiated neuroblastoma cells, Neuro2a.</p> <p>Results</p> <p>A 4 h exposure to homocysteine in a concentration range of 10–100 μM did not affect cell viability and ROS production in Neuro2a cell cultures. Instead, ROS levels were increased by two-three folds in cells treated with 250 μM and 500 μM homocysteine, respectively, in comparison with control cells. Also, the highest homocysteine dose significantly reduced the viable cell number by 40%. Notably, the treatment with homocysteine (250 μM–500 μM) in the presence of antioxidants, such as N-acetylcysteine and IRFI 016, a synthetic α-tocopherol analogue, recovered cell viability and significantly reduced homocysteine-evoked increases in ROS production. Moreover, antioxidants, particularly IRFI 016, were able to counteract NF-κB activation induced by 250 μM homocysteine.</p> <p>Cell treatment with 250 μM homocysteine also triggered the onset of apoptosis, as demonstrated by the increased expression of early apoptotic markers such as Bax, caspase-3 and p53. In contrast, Bcl2 expression was not affected by homocysteine exposure. Interestingly, the specific inhibition of NF-κB nuclear translocation by the synthetic peptide SN50 was able to almost completely suppress the homocysteine-evoked rises in pro-apoptotic protein expression as well as in caspase-3 activity. Further, also IRFI 016 and N-acetylcysteine were able to significantly reduce caspase-3 activation induced by homocysteine treatment.</p> <p>Conclusion</p> <p>These observations suggest an involvement of redox state alterations and activated NF-κB in apoptosis onset triggered by homocysteine in neuroblastoma cells Neuro2a. However, further investigations are needed to characterize molecular events involved in the NF-κB activation induced by homocysteine.</p

Hereditary Transthyretin Amyloidosis: How to Differentiate Carriers and Patients Using Speckle-Tracking Echocardiography

Background: Hereditary transthyretin amyloidosis is a rare disease caused by transthyretin (TTR) gene mutations. The aim of our study was to identify early signs of cardiac involvement in patients with a TTR gene mutation in order to differentiate carriers from patients with neurological or cardiac disease. Methods: A case-control study was carried out on 31 subjects with the TTR mutation. Patients were divided into three groups: 23% with cardiac amyloidosis and polyneuropathy (group A), 42% with only polyneuropathy (group B) and 35% carriers (group C). Speckle-tracking echocardiography (left-ventricular global longitudinal strain-GLS, atrial stiffness) was performed in all patients. The apical/basal longitudinal strain ratio (SAB) and relative apical sparing (RAS) were assessed in all subjects. Results: Analyzing groups C and B, we only found a significant difference in the SAB (p-value 0.001) and RAS (p-value 0.039). These parameters were significantly more impaired in group A compared to group B (SAB p-value 0.008; RAS p-value 0.002). Also, atrial stiffness was significantly impaired in groups A and B compared to group C. Conclusions: Our study suggests the diagnostic role of the SAB and RAS in cardiac amyloidosis. The SAB and RAS showed a gradual increase from carriers to patients with neurological and cardiac diseases. Thus, these parameters, in addition to atrial stiffness, could be used to monitor carriers. More extensive data are needed

Monitoring of cardiovascular risk factors in competitive athletes

It is well known that physical activity can improve cardiovascular risk factors, but it is also true that strenuous activity may result detrimental for the athlete health. Among the emerging markers of cardiovascular risk, plasma homocysteine (Hcy) plays a prominent role, since it has been shown its significant increase in competitive athletes. Some research has concluded that Hcy levels may be influenced by the duration, intensity and type of exercise, whereas other studies have identified lifestyle factors, such as smoking, eating habits, alcohol consumption, age, elevated blood pressure and genetic factors, as factors that contribute to increased plasma concentrations of Hcy. Polymorphisms in the methylenetetrahydrofolate reductase gene (MTHFR) (677C/T, 1298A/C) are reported to modulate homocysteine levels. The aim of this work was to identify a genetic profile of risk for cardiovascular disease in two populations of competitive athletes, football players (n = 19) and those engaged in athletics (n=37). The distribution of MTHFR A1298C and C677T polymorphisms was examined by Real-time PCR allelic discrimination on genomic DNA isolated from lymphocytes of whole peripheral blood. The serum levels of Hcy were determined by HPLC method, while vitamin B12 and folate by RIA technique. The data showed that 50% of the subjects in both groups are carrier of MTHFR C677T polymorphism either in heterozygous or homozygous state. In addition, all subjects had mild hyperhomocysteinemia (13-27 micromol/L). The highest mean levels of Hcy were recorded in the football players, and the differences compared to those engaged in athletics were very significant (21.8 ± 11.6 vs. 13.5 ± 6.6, p &lt;0.05). The increase of Hcy could be ascribed mainly to the diet style of the recruited subjects, characterized by a high consumption of red meat and very low intake of B vitamins. Moreover, this increase may also be explained in relation to the type of exercise required in football, that is considered an intermittent intensity sport. The preliminary results of this study suggest that screening for the MTHFR variants C677T and A1298C should be included in the panel of screening for cardiovascular risk in competitive athletes

Hyperhomocysteinemia and MTHFR Polymorphisms as Antenatal Risk Factors of White Matter Abnormalities in Two Cohorts of Late Preterm and Full Term Newborns

Higher total homocysteine (tHcy) levels, and C677T and A1298C methylenetetrahydrofolate (MTHFR) polymorphisms, have been reported in preterm or full term newborns with neonatal encephalopathy following perinatal hypoxic-ischemic insult. This study investigated the causal role of tHcy and MTHFR polymorphisms together with other acquired risk factors on the occurrence of brain white matter abnormalities (WMA) detected by cranial ultrasound scans (cUS) in a population of late preterm and full term infants. A total of 171 newborns (81 M, 47.4%), 45 (26.3%) born <37 wks, and 126 (73.7%) born ≥37 wks were recruited in the study. cUS detected predominant WMA pattern in 36/171 newborns (21.1%) mainly characterized by abnormal periventricular white matter signal and mild-to-moderate periventricular white matter volume loss with ventricular dilatation (6/36, 16.6%). WMA resulted in being depending on tHcy levels (P<0.014), lower GA (P<0.000), lower Apgar score at 1 minutes (P<0.000) and 5 minutes (P<0.000), and 1298AC and 677CT/1298AC genotypes (P<0.000 and P<0.000). In conclusion, both acquired and genetic predisposing antenatal factors were significantly associated with adverse neonatal outcome and WMA. The role of A1298C polymorphism may be taken into account for prenatal assessment and treatment counseling

Canonical and truncated transglutaminase-2 regulate mucin-1 expression and androgen independency in prostate cancer cell lines

Androgen independency is associated with poor prostate cancer (PCa) survival. Here we report that silencing of transglutaminase-2 (TG2) expression by CRISPR-Cas9 is associated with upregulation of androgen receptor (AR) transcription in PCa cell lines. Knockout of TG2 reversed the migratory potential and anchorage independency of PC3 and DU145 cells and revealed a reduced level of mucin-1 (MUC1) RNA transcript through unbiased multi-omics profiling, which was restored by selective add-back of the truncated TG2 isoform (TGM2_v2). Silencing of AR resulted into increased MUC1 in TG2KO PC3 cells showing that TG2 affects transcriptional regulation of MUC1 via repressing AR expression. Treatment of PC3 WT cell line with TG2 inhibitor ZDON led to a significant increase in AR expression and decrease in MUC1. ZDON also blocked the formation of MUC1-multimers labelled with TG amine-donor substrates in reducing conditions, revealing for the first time a role for TG2, which we show to be externalised via extracellular vesicles, in MUC1 stabilisation via calcium-dependent transamidation. A specific antibody towards TGM2_v2 revealed its restricted nuclear location compared to the canonical long form of TG2 (TGM2_v1), which is predominantly cytosolic, suggesting that this form contributes to the previously suggested TG2-mediated NF-κB activation and AR transcriptional repression. As TGM2_v2 transcription was increased in biopsies of early-stage prostate adenocarcinoma (PRAD) patients compared to subjects presenting inflammatory prostatitis, and total TG2 protein expression significantly increased in PRAD versus normal tissue, the role of TG2 and its truncated form as a prostate malignancy marker is suggested. In conclusion, this investigation has provided the first unbiased discovery of a novel pathway mediated by TG2 via MUC1, which is shown to contribute to androgen insensitivity and malignancy of PCa cells and be upregulated in PCa biopsies, with potential relevance to cancer immune evasion