Coupling factor 6 enhances the spontaneous microaggregation of platelets by decreasing cytosolic cAMP irrespective of antiplatelet therapy

Pathogenesis of cardiovascular diseases: effects of mitochondrial CF6 on endothelial cell function

Cardiovascular disease (CVD) stands as a predominant global cause of morbidity and mortality, necessitating effective and cost-efficient therapies for cardiovascular risk reduction. Mitochondrial coupling factor 6 (CF6), identified as a novel proatherogenic peptide, emerges as a significant risk factor in endothelial dysfunction development, correlating with CVD severity. CF6 expression can be heightened by CVD risk factors like mechanical force, hypoxia, or high glucose stimuli through the NF-κB pathway. Many studies have explored the CF6-CVD relationship, revealing elevated plasma CF6 levels in essential hypertension, atherosclerotic cardiovascular disease (ASCVD), stroke, and preeclampsia patients. CF6 acts as a vasoactive and proatherogenic peptide in CVD, inducing intracellular acidosis in vascular endothelial cells, inhibiting nitric oxide (NO) and prostacyclin generation, increasing blood pressure, and producing proatherogenic molecules, significantly contributing to CVD development. CF6 induces an imbalance in endothelium-dependent factors, including NO, prostacyclin, and asymmetric dimethylarginine (ADMA), promoting vasoconstriction, vascular remodeling, thrombosis, and insulin resistance, possibly via C-src Ca2+ and PRMT-1/DDAH-2-ADMA-NO pathways. This review offers a comprehensive exploration of CF6 in the context of CVD, providing mechanistic insights into its role in processes impacting CVD, with a focus on CF6 functions, intracellular signaling, and regulatory mechanisms in vascular endothelial cells.

Incidence and characteristics of spontaneous platelet macro-aggregation in acute ischemic stroke

Spontaneous platelet aggregation is a trigger for additional development of larger thrombi. Micro-aggregation is observed in 10% of diabetes approximately and blocked by P2Y12 inhibitors, whereas macro-aggregation is associated with overexpression of platelet α₂-adrenoreceptors and is not blocked by conventional anti-platelet medicines. We examined the incidence of spontaneous platelet macro-aggregation (SPMA) in acute ischemic stroke and analyzed its clinical characteristics. Out of 665 consecutive acute ischemic strokes, SPMA was found in 10 patients (1.5%, one tenth of micro-aggregation) despite no detection in 588 control subjects. Types of ischemic stroke were 4 atherothrombotic, 4 cardioembolic, and 2 lacunar strokes. Stroke with SPMA exhibited higher (worse) values of modified Rankin Scales (mRS) at discharge (3.00 ± 0.53 vs 1.93 ± 0.07, p = 0.042 by Wilcoxon) compared with stroke without SPMA despite no difference at admission. The proportion of patients who were functionally independent (score 0-2 on the mRS) at discharge was lower in stroke with SPMA compared with stroke without SPMA (p < 0.05 by chi-square test; OR 3.60, 95% CI 1.08-12.03; RR 2.04, 95% CI 1.05-2.86). It was intriguing that severe (high magnitude) SPMA was observed in 4 atherothrombotic stroke. Although anti-platelet therapy underwent, the proportion of atherothrombotic patients who were functionally improved and independent at discharge was lower in the presence of SPMA compared with the absence of SPMA (p < 0.05 by chi-square test). The patients with SPMA were more likely to be older, having major disabilities, being less functionally improved during hospitalization, and being less functionally independent at discharge.

Collagen-Induced Platelet Aggregates, Diabetes, and Aspirin Therapy Predict Clinical Outcomes in Acute Ischemic Stroke

BACKGROUND

Aggregation of platelets is a trigger for additional development of larger thrombi. This study aimed to identify factors that may affect platelet aggregability and their role in clinical outcomes in acute ischemic stroke.

METHODS

Consecutive acute ischemic stroke patients (n = 352) who were transferred within 24 hours after its onset were enrolled. Peripheral venous blood was sampled to measure platelet aggregability and other parameters.

RESULTS

Mean values of spontaneous small-sized platelet aggregates and collagen- or adenosine diphosphate (ADP)-induced large-sized aggregates were elevated in acute ischemic stroke. In atherothrombotic stroke (n = 178), collagen and ADP-induced large-sized aggregates were positively correlated with HbA1c, respectively. High incidence of the modified Rankin Scales (mRS) 5-6 at discharge was associated with diabetes complication (odds ratio [OR] 8.77, 95% confidence interval [CI] 1.32-57.56). The proportion of patients who were functionally independent (the mRS 0-2) at discharge was lower in the middle tertile of collagen and ADP-induced large-sized aggregates than their low tertile (OR 2.46, 95% CI 1.09-5.58; OR 2.43, 95% CI 1.05-5.59, respectively). Prestroke administration of aspirin recovered the proportion of independence at discharge (OR 0.25, 95% CI 0.06-0.99), and ameliorated incidence of the mRS 5-6. On logistic regression analysis, diabetes, HbA1c, collagen-induced large-sized aggregates, and prestroke administration of aspirin remained independent predictors of clinical outcomes in atherothrombotic stroke. In cardioembolic and lacunar stroke, no relations with clinical outcomes were found.

CONCLUSIONS

High plasma level of HbA1c is involved in enhanced platelet aggregability in acute atherothrombotic stroke patients, and prestroke administration of aspirin may be beneficial to clinical outcomes.

Identification and characterization of a highly thermostable bacteriophage lysozyme

Pseudomonas aeruginosa bacteriophage phiKMV is a T7-like lytic phage. Liquid chromatography-mass spectrometry of the structural proteins revealed gene product 36 (gp36) as part of the phiKMV phage particle. The presence of a lysozyme domain in the C terminal of this protein (gp36C) was verified by turbidimetric assays on chloroform-treated P. aeruginosa PAO1 and Escherichia coli WK6 cells. The molecular mass (20,884 Da) and pI (6.4) of recombinant gp36C were determined, as were the optimal enzymatic conditions (pH 6.0 in 16.7 mM phosphate buffer) and activity (4800 U/mg). Recombinant gp36C is a highly thermostable lysozyme, retaining 26% of its activity after 2 h at 100 degrees C and 21% after autoclaving. This thermostability could prove an interesting characteristic for food conservation technology.