We tested the hypothesis that plasma brain natriuretic peptide (BNP) levels are elevated in patients with acute cerebrovascular diseases (CVD) independent of heart disease, and reflect CVD severity. After careful evaluations for heart disease, the study included 79 consecutive patients with CVD without any evidence of heart disease admitted within 48 h after onset (71 ± 10 years), and 26 control subjects without CVD (CT,
The morning surge in blood pressure (BP) is related to the morning occurrence of lethal cardiovascular events. We tested the hypothesis that salt intake may be associated with the morning surge in BP in essential hypertension. Seventy-six patients were admitted and placed on a low salt diet (2 g/day) for 7 days followed by a high salt diet (20-23 g/day) for another 7 days. At the end of each salt diet, 24-h ambulatory BP and heart rate monitorings and head-up tilt (HUT) test were performed. Patients whose average mean BP (MBP) was increased by more than 10% by salt loading were assigned to the salt-sensitive (SS) group (n ؍ 37); the remaining patients, whose MBP was increased by less than 10%, were assigned to the non-salt-sensitive (NSS) group (n ؍ 39). The increase in ambulatory MBP during 6.30-8.00 am above the baseline (2.00-4.00 am) was significantly
CF6 is elevated in patients with stroke independently of risk factors. Since Hcy and vitamin treatment affect CF6 levels in stroke, CF6 appears to be a novel molecule for the pathogenesis and treatment of stroke.
The plasma brain natriuretic peptide (BNP) level is increased in the acute phase of human stroke, but its source and function are unclear. Recently, we showed that the BNP level was higher in atherothrombotic cerebral infarction (69.1±9.4 pg/ml) than in control subjects (31.1±5.4 pg/ml), and that the BNP level in ischemic stroke was positively correlated with the NIH Stroke Scale (r=0.41, p<0.05) and infarct volume (r=0.34, p<0.05). Astrocytes provide metabolic and trophic support to neurons and modulate synaptic activities. At the early stage of brain ischemia, astrocytes are swollen, and their damage may compromise postischemic neuronal survival. We tested the hypothesis that human astrocytes produce BNP under hypoxia, and this endogenous BNP protects against apoptosis in an autocrine fashion. The human astrocyte cell line, U373MG, was exposed to hypoxia (O
2
≤1%) for 24 hours. The ratio of BNP to GAPDH mRNA was increased by 7.7±.0 fold after 12-hour hypoxia and further increased by 8.6±1.6 fold after 24-hour hypoxia compared with that in 3-hour normoxia (both, p<0.01). The protein expression assessed by Western blot was increased by 2.0±0.4 fold at 24 hours (n=5, p<0.05). Tyrosine phosphorylation of c-Src was observed by 2.0±0.2-fold increase at 30 minutes. These responses to hypoxia were all blocked by pretreatment with PP1 at 50μM, an inhibitor of c-Src. Apoptosis was measured by detecting caspase activation by flow cytometry, and it was increased by 2.5±0.1 fold after 24-hour hypoxia compared with that in normoxia. To investigate the role of up-regulated BNP in apoptosis, we performed the loss of function test by transfecting a specific siRNA for NPPB that suppressed BNP by more than 80%. The activity of caspases in the BNP knockdown cells was increased by 3.2±0.2 fold after 24-hour hypoxia compared with that in normoxia (n=5, p<0.001), and it was greater than that in the cells transfected with non-targeting siRNA. These results indicate that hypoxia increases BNP gene expression through the c-Src-dependent signaling cascade in the human astrocytes. Endogenous BNP shows brain protection via the anti-apoptotic effect. BNP may be useful in the treatment of ischemic brain diseases.
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