Various studies describe increased concentrations of transforming growth factor-beta (TGF-beta) in brain tissue after acute brain injury. However, the role of endogenously produced TGF-beta after brain damage to the CNS remains to be clearly established. Here, the authors examine the influence of TGF-beta produced after an episode of cerebral ischemia by injecting a soluble TGF-beta type II receptor fused with the Fc region of a human immunoglobulin (TbetaRIIs-Fc). First, this molecular construct was characterized as a selective antagonist of TGF-beta. Then, the authors tested its ability to reverse the effect of TGF-beta1 on excitotoxic cell death in murine cortical cell cultures. The addition of 1 microg/mL of TbetaRIIs-Fc to the exposure medium antagonized the neuroprotective activity of TGF-beta1 in N-methyl-D-aspartate (NMDA)-induced excitotoxic cell death. These results are consistent with the hypothesis that TGF-beta1 exerts a negative modulatory action on NMDA receptor-mediated excitotoxicity. To determine the role of TGF-beta1 produced in response to brain damage, the authors used a model of an excitotoxic lesion induced by the intrastriatal injection of 75 nmol of NMDA in the presence of 1.5 microg of TbetaRIIs-Fc. The intrastriatal injection of NMDA was demonstrated to induce an early upregulation of the expression of TGF-beta1 mRNA. Furthermore, when added to the excitotoxin, TbetaRIIs-Fc increased (by 2.2-fold, P < 0.05) the lesion size. These observations were strengthened by the fact that an intracortical injection of TbetaRIIs-Fc in rats subjected to a 30-minute reversible cerebral focal ischemia aggravated the volume of infarction. In the group injected with the TGF-beta1 antagonist, a 3.5-fold increase was measured in the infarction size (43.3 +/- 9.5 versus 152.8 +/- 46.3 mm3; P < 0.05). In conclusion, by antagonizing the influence of TGF-beta in brain tissue subjected to excitotoxic or ischemic lesion, the authors markedly exacerbated the resulting extent of necrosis. These results suggest that, in response to such insults, brain tissue responds by the synthesis of a neuroprotective cytokine, TGF-beta1, which is involved in the limitation of the extent of the injury. The pharmacologic potentiation of this endogenous defensive mechanism might represent an alternative and novel strategy for the therapy of hypoxic-ischemic cerebral injury.
Background-Reactive oxygen species play a critical role in inducing apoptosis. The small GTPase p21 Ras and the ERK1/2 MAPK have been proposed as key regulators of the signaling cascade triggered by oxidative stress (H 2 O 2 ). Harvey-Ras (Ha-Ras) and Kirsten-Ras (Ki-Ras) isoforms are so far functionally indistinguishable, because they activate the same downstream effectors, including ERK1/2. Moreover, ERK1/2 signaling has been involved in both protection and induction of apoptosis. Methods and Results-Human umbilical vein endothelial cells (HUVECs) were subjected to H 2 O 2 , and apoptosis was detected by fluorescence-activated cell sorting analysis, fluorescence microscopy, and caspase-3 activation. Transfection of Ha-Ras and Ki-Ras genes in HUVECs was performed to evaluate the response to H 2 O 2 . We have found that, whereas Ha-Ras decreases tolerance to oxidative stress, Ki-Ras has a potent antiapoptotic activity. Both effects are mediated by ERK1/2. Tolerance to H 2 O 2 is encoded by a unique stretch of lysines at the COOH terminus of the Ki-Ras, lacking in Ha-Ras, and it is relatively independent of the farnesylated anchor. Inhibition of p21 Ras signaling by farnesylation inhibitors increased the resistance to apoptosis in Ha-Ras-expressing cells. Conclusions-These
In hyperglycemic patients with STEMI, optimal peri-procedural glycemic control by reducing oxidative stress and inflammation may improve the outcome after PCI.
ObjectivesTo evaluate clinical outcomes in patients with diabetes, treated by cardiac resynchronization therapy with a defibrillator (CRT-d), and glucagon-like peptide 1 receptor agonists (GLP-1 RA) in addition to conventional hypoglycemic therapy vs. CRTd patients under conventional hypoglycemic drugs.BackgroundPatients with diabetes treated by CRTd experienced an amelioration of functional New York Association Heart class, reduction of hospital admissions, and mortality, in a percentage about 60%. However, about 40% of CRTd patients with diabetes experience a worse prognosis.Materials and methodsWe investigated the 12-months prognosis of CRTd patients with diabetes, previously treated with hypoglycemic drugs therapy (n 271) vs. a matched cohort of CRTd patients with diabetes treated with GLP-1 RA in addition to conventional hypoglycemic therapy (n 288).ResultsAt follow up CRTd patients with diabetes treated by GLP-1 RA therapy vs. CRTd patients with diabetes that did not receive GLP-1 RA therapy, experienced a significant reduction of NYHA class (p value < 0.05), associated to higher values of 6 min walking test (p value < 0.05), and higher rate of CRTd responders (p value < 0.05). GLP-1 RA patients vs. controls at follow up end experienced lower AF events (p value < 0.05), lower VT events (p value < 0.05), lower rate of hospitalization for heart failure worsening (p value < 0.05), and higher rate of CRTd responders (p value < 0.05). To date, GLP-1 RA therapy may predict a reduction of AF events (HR 0.603, CI [0.411–0.884]), VT events (HR 0.964, CI [0.963–0.992]), and hospitalization for heart failure worsening (HR 0.119, CI [0.028–0.508]), and a higher CRT responders rate (HR 3.707, CI [1.226–14.570]).ConclusionsGLP-1 RA drugs in addition to conventional hypoglycemic therapy may significantly reduce systemic inflammation and circulating BNP levels in CRTd patients with diabetes, leading to a significant improvement of LVEF and of the 6 min walking test, and to a reduction of the arrhythmic burden. Consequently, GLP-1 RA drugs in addition to conventional hypoglycemic therapy may reduce hospital admissions for heart failure worsening, by increasing CRTd responders rate.Trial registration NCT03282136. Registered 9 December 2017 “retrospectively registered”
Background: Elevated total plasma homocysteine (tHcy) levels are considered a risk factor for cerebrovascular disease and may also play an important role in the pathogenesis of Alzheimer’s disease (AD). High values of plasma tHcy and low levels of vitamin B12 and folate are frequently present in AD patients. Moreover, the homozygous mutation (C677T) of the methylene tetrahydrofolate reductase (MTHFR) gene, related to a thermolabile type of the encoded enzyme, causes hyperhomocysteinemia by reducing the 5-methyltetrahydrofolate availability. Objective: The aim of the study was to investigate plasma levels of folate, vitamin B12 and tHcy in patients with AD. These values were also related to the severity and the duration of the disease and to the possible role of the MTHFR genotype (C677T). Method: Plasma tHcy levels, homozygosity for the C677T mutation of the MTHFR gene, and folate and vitamin B12 plasma levels were evaluated in 74 patients with AD (45 men, 29 women, mean age 68 years) and in 74 healthy matched controls (42 men, 32 women, mean age 68 years). Results: AD patients had higher mean (± SD) plasma levels of tHcy (20.9 ± 15 µmol/l compared to 11.8 ± 5 µmol/l, p < 0.001) and lower mean plasma folate (5.7 ± 2.1 ng/ml compared to 8.5 ± 3.2 ng/ml, p < 0.001) and vitamin B12 (491 ± 144 pmol/l compared to 780 ± 211 pmol/l, p < 0.001) concentrations. Homozygosity for the C677T mutation of the MTHFR gene had a similar prevalence among controls (18%) and AD patients (20%). Homozygous AD patients (n = 15) had higher plasma tHcy values than nonhomozygotes, in spite of similar mean plasma folate and vitamin B12 levels. This difference in plasma tHcy levels was not observed in controls. Patients with levels of plasma tHcy above and of plasma folate below the normal limits were more frequent in the homozygous AD group. The duration of the disease correlated with plasma levels of tHcy (r = +0.832, p < 0.001), plasma folate (r = –0.580, p < 0.05), and vitamin B12 (r = –0.460, p < 0.05). However, when all the data were corrected for age, serum creatinine levels, and duration of the disease, mean plasma tHcy, folate, and vitamin B12 levels were not statistically different between controls and AD patients. Conclusions: Our data suggest that rather than a risk factor for AD, hyperhomocysteinemia is related to its progression and increasing severity. This might be particularly relevant in homozygotes for the C677T mutation of the MTHFR gene and supports the possible need for continuous supplements in this setting.
Background: Reconstituted high-density lipoprotein (rHDL) is prepared from apolipoprotein A-I, isolated from human plasma, and soybean-derived phosphatidylcholine and exhibits biochemical and functional characteristics similar to endogenous nascent high-density lipoprotein (HDL). This study tested the hypothesis that pretreatment with rHDL may reduce neuronal damage in 2 experimental rat models of stroke. Methods: In the first model, an excitotoxic lesion was induced by unilateral injection of N-methyl-D-aspartate (NMDA) in the right striatum (excitotoxic lesion model). In the second model, temporary occlusion of the middle cerebral artery (MCA) was attained by inserting a nylon thread through the carotid artery and blood flow was restored 30 min later (MCAo model). In both models, either rHDL (120 mg/kg) or saline (control) were infused over 4 h, starting 2 h before the injection of NMDA or the induction of ischemia, respectively. 24 h after the interventions, the rats were sacrificed and the brains removed for histochemical preparation. The necrotic area was delimited using an image analysis system. In addition, the levels of reactive oxygen species (ROS) in human endothelial (ECV 304) and neuroblastoma (SK-N-BE) cell lines were measured fluorometrically as 2′,7′-dichlorofluorescein fluorescence in the presence and absence of rHDL and under basal and stress-induced conditions. Results: In the excitotoxic lesion and MCAo models, pretreatment with rHDL significantly reduced the brain necrotic area by 61 and 76%, respectively (p < 0.01). Overnight incubation of ECV 304 and SK-N-BE cells with 0.5 mg/ml rHDL decreased basal and stress-induced ROS levels by 73 and 72% (ECV 304) and by 76 and 43% (SK-N-BE), respectively (p < 0.01). Conclusion: These results suggest that rHDL reduces neuronal damage after onset of ischemic stroke, possibly by involving an anti-oxidative mechanism. Thus, rHDL may be a powerful neuroprotective tool for the treatment of cerebrovascular diseases.
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