Interaction of albumin, arachidonic acid and prostanoids in platelets

Can C-reactive protein/albumin ratio be a prognostic factor in acute stroke patients undergoing mechanical thrombectomy?

INTRODUCTION

C-reactive protein (CRP) and albumin are markers synthesized by the liver and may reflect inflammatory responses. CRP/Albumin ratio (CAR) serves better to reflect the inflammatory state and therefore the prognosis. Worse prognosis is reported in previous studies when CAR rate on admission is high in patients with stroke, aneurysmal subarachnoid hemorrhage, malignancy or patients followed in intensive care units. We aimed to investigate the relation of CAR with prognosis in mechanical thrombectomy performed acute stroke patients.

MATERIALS AND METHODS

Stroke patients admitted to five different stroke centers between January 2021 and August 2022 undergoing mechanical thrombectomy were included and retrospectively analyzed. The CAR ratio was calculated as the ratio of CRP to albumin level in the venous blood samples. Primary outcome was the relation between CAR and functional outcome at 90 days determined by modified Rankin Scale (mRS).

RESULTS

This study included 558 patients with a mean age of 66,5 ± 12.5 years (age range:18-89 years) best cutoff value of the CAR was 3.36, with 74.2 % sensitivity and 60.7 % specificity (Area under the curve: 0.774; 95 %CI: 0.693-0.794). There was no significant correlation between CAR rate and age, CAR rate and NIHSS on admission, and also between CAR rate and symptom recanalization (p > 0.05). CAR ratio in the mRS 3-6 group was statistically significantly higher (p < 0.001). In the multivariate analyses, CAR showed an association with 90-day mortality (odds ratio, 1.049; 95 % CI, 1.032-1.066) CONCLUSION: In acute ischemic stroke patients treated with mechanical thrombectomy, CAR may be one of the factors affecting poor clinical outcome and/or mortality in patients undergoing mechanical thrombectomy. Upcoming similar studies in this patient group may better clarify the prognostic role of CAR.

Prognostic value of inflammation biomarkers for 30-day mortality in critically ill patients with stroke

Objective

To explore the values of neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), neutrophil to albumin ratio (NAR), prognostic nutritional index (PNI), systemic immune inflammatory index (SII) and red cell distribution width to albumin ratio (RA) for evaluating the risk of 30-day mortality of ischemic stroke or hemorrhagic stroke patients.

Methods

In this cohort study, the data of 1,601 patients diagnosed with stroke were extracted from the Medical Information Mart for Intensive Care III (MIMIC-III) database. Among them, 908 were hemorrhagic stroke patients and 693 were ischemic stroke patients. Demographic and clinical variables of patients were collected. Univariate and multivariable Cox regression were performed to evaluate the predictive values of NLR, PLR, SII, NAR, RA, and PNI for 30-day mortality in hemorrhagic stroke or ischemic stroke patients. The receiver operator characteristic (ROC) curves were plotted to assess the predictive values of NLR, NAR, and RA for 30-day mortality of hemorrhagic stroke patients.

Results

At the end of follow-up, 226 hemorrhagic stroke patients and 216 ischemic stroke patients died. The elevated NLR level was associated with increased risk of 30-day mortality in hemorrhagic stroke [hazard ratio (HR) = 1.17, 95% confidence interval (CI): 1.06-1.29]. The increased NAR level was associated with elevated risk of 30-day mortality in hemorrhagic stroke (HR = 1.16, 95% CI: 1.02-1.30). The high RA level was linked with increased risk of 30-day mortality (HR = 1.44, 95% CI: 1.23-1.69). No significant correlation was observed in these inflammation biomarkers with the risk of 30-day mortality in ischemic stroke patients. The area under the curves (AUCs) of NLR, RA, and NAR for evaluating the risk of 30-day mortality of hemorrhagic stroke patients were 0.552 (95% CI: 0.503-0.601), 0.644 (95% CI: 0.590-0.699) and 0.541 (95% CI: 0.490-0.592).

Conclusion

NLR, NAR, and RA were potential prognostic biomarkers for predicting 30-day mortality of hemorrhagic stroke patients, which might provide clinicians an easy and cheap way to quickly identify patients with high risk of mortality.

Serum Albumin and Risks of Stroke and Its Subtypes - The Circulatory Risk in Communities Study (CIRCS)

BACKGROUND

Few studies have investigated the association between serum albumin levels and the risk of stroke subtypes among the general Japanese population.

METHODS AND RESULTS

In this study, 5,071 men and 7,969 women aged 40-74 years, initially free from stroke, coronary artery disease, and kidney and hepatic failure, and residing in 4 Japanese communities completed a baseline risk factor survey between 1985 and 1994. During the 24-year follow-up, 528 men and 553 women experienced stroke. In the entire study cohort, multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) of total stroke, ischemic stroke, and intracerebral hemorrhage for the lowest vs. highest quartiles of serum albumin were 1.45 (1.18-1.77), 1.52 (1.17-1.97), and 1.57 (1.04-2.37), respectively. In men, multivariable HRs (95% CIs) for total stroke, ischemic stroke, and intracerebral hemorrhage in the lowest vs. highest serum albumin quartile were 1.44 (1.07-1.92), 1.48 (1.03-2.11) and 1.71 (0.92-3.18), respectively, whereas in women they were 1.50 (1.13-1.99), 1.63 (1.11-2.39), and 1.56 (0.89-2.74), respectively. Similar inverse associations were observed for each of the ischemic stroke subtypes, but not for subarachnoid hemorrhage.

CONCLUSIONS

Low serum albumin levels were associated with an increased risk of total stroke, ischemic stroke, ischemic stroke subtypes, and intracerebral hemorrhage.

Association of C-Reactive Protein to Albumin Ratio in Patients with Isolated Coronary Artery Ectasia

Fundamento

A ectasia da artéria coronária (EAC) é definida como a dilatação difusa ou localizada do lúmen da artéria coronária com diâmetro de 1,5 a 2,0 vezes o diâmetro da artéria coronária normal adjacente. A relação proteína C-reativa/albumina (CAR, sigla em inglês) é um marcador inflamatório útil que tem sido documentado em doença arterial coronariana.

Objetivo

Analisar a associação entre a EAC e a CAR.

Métodos

Um protocolo caso-controle foi utilizado neste estudo. Foram incluídos 102 pacientesconsecutivos com EAC isolada sem estenose (56 homens e 46 mulheres; idade média de 60,4 ± 8,8 anos). O grupo controle era constituido pelo mesmo número de pacientes pareados por sexo e idade com artérias coronárias normais (55 homens e 47 mulheres; idade média de 61,2 ± 9,1 anos). Características clínicas, achados laboratoriais e histórico de uso de medicamentos foram registrados. Foram realizados teste t de Student, teste U de Mann-Whitney, teste do qui-quadrado, análise de regressão linear e logística. Foi considerado estatisticamente significativo p bilateral < 0,05.

Resultados

A CAR estava aumentada nos pacientes com EAC em comparação com os controles (32 e 16; p < 0,001). Além disso, foi verificado que a CAR era um preditor independente da EAC (razão de chances = 2,202; intervalo de confiança 95%, 1,184 – 5,365; p < 0,001).

Conclusão

No presente estudo, determinamos que os níveis da CAR estavam significativamente mais altos no grupo EAC que no grupo controle e a CAR estava significativamente correlacionada com a EAC. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)

Prognostic value of C-reactive protein/albumin ratio in ST-segment elevation myocardial infarction

Serum C-reactive protein (CRP)/albumin ratio (CAR) is demonstrated as a more precise marker in determining the prognosis of critical diseases than albumin and CRP levels, separately. Recently, inflammatory biomarkers are increasingly used for both screening and prognosis of coronary artery disease (CAD). As an ischemia-dependent risk index, CAR is an independent marker of in-hospital and long-term all-cause mortality in ST-segment elevation myocardial infarction (STEMI) treated with percutaneous coronary intervention. The results indicate that CAR is a more effective prognostic marker than either CRP or albumin.

Regulation of CYP2J2 and EET Levels in Cardiac Disease and Diabetes

Cytochrome P450 2J2 (CYP2J2) is a known arachidonic acid (AA) epoxygenase that mediates the formation of four bioactive regioisomers of cis-epoxyeicosatrienoic acids (EETs). Although its expression in the liver is low, CYP2J2 is mainly observed in extrahepatic tissues, including the small intestine, pancreas, lung, and heart. Changes in CYP2J2 levels or activity by xenobiotics, disease states, or polymorphisms are proposed to lead to various organ dysfunctions. Several studies have investigated the regulation of CYP2J2 and EET formation in various cell lines and have demonstrated that such regulation is tissue-dependent. In addition, studies linking CYP2J2 polymorphisms to the risk of developing cardiovascular disease (CVD) yielded contradictory results. This review will focus on the mechanisms of regulation of CYP2J2 by inducers, inhibitors, and oxidative stress modeling certain disease states in various cell lines and tissues. The implication of CYP2J2 expression, polymorphisms, activity and, as a result, EET levels in the pathophysiology of diabetes and CVD will also be discussed.

Plasma albumin and platelet function: relevance to atherogenesis and thrombosis

Two papers published in this journal(1,2) during the past year remind us that plasma albumin concentrations can influence platelet function. These publications, together with epidemiological evidence showing that low plasma concentrations of albumin predict mortality from cardiovascular disease(3,4) have prompted this review.

Inhibitory action of fatty acids on calcium fluxes in thyroid FRTL-5 cells

In the present study, we wanted to investigate the action of fatty acids on agonist-evoked changes in intracellular free calcium ([Ca2+]i) in thyroid FRTL-5 cells. Stimulating Fura 2 loaded cells with long chain unsaturated fatty acids increased [Ca2+]i in a dose-dependent manner. This increase was in part dependent on extracellular calcium. Long chain saturated fatty acids and short chain fatty acids had no effects on [Ca2+]i per se. Pretreatment of the cells with long chain unsaturated fatty acids almost totally inhibited both the ATP- and thapsigargin-evoked release of sequestered calcium and the entry of extracellular calcium. Long chain saturated fatty acids also attenuated the ATP-evoked increase in [Ca2+]i, while short chain fatty acids had no effects on the ATP-evoked change in [Ca2+]i. The inhibitory effect of long chain unsaturated fatty acids on agonist-evoked changes in [Ca2+]i was not dependent on activation of protein kinase C, and was not due to an enhanced efflux of calcium. These fatty acids rapidly acidified the cytosol in the cells, which could, in part, explain the inhibitory effect of the long chain unsaturated fatty acids on agonist-evoked changes in [Ca2+]i. Addition of bovine serum albumin to the cells rapidly reversed the inhibitory effect of the fatty acids on [Ca2+]i, and restored pHi. Thus, fatty acids could be potential modulators of calcium signaling in FRTL-5 cells, possibly by modulating calcium entry at the level of the plasma membrane.

TRH-evoked entry of extracellular calcium in GH4C1 cells: possible importance of arachidonic acid metabolites

Previous studies have shown that stimulating pituitary GH4C1 cells with thyrotropin-releasing hormone (TRH) evoked a biphasic change in cytosolic free Ca2+ concentration ([Ca2+]i): a rapid release of sequestered Ca2+ due to the production of inositol-1,4,5-trisphosphate, and Ca2+ entry via both voltage-operated Ca2+ channels and a presently unknown voltage-independent influx pathway. The aim of the present study was to further evaluate to which extent the TRH-evoked changes in [Ca2+]i were dependent on entry of extracellular Ca2+, and which mechanisms participated in regulating this Ca2+ entry. Pretreatment of the cells with 4-bromophenylacylbromide (an inhibitor of phospholipase A2), nordihydroguaiaretic acid (an inhibitor of lipoxygenase), and econazole (an inhibitor of both lipoxygenase and cytochrome P-450 enzymes), attenuated the TRH-evoked increase in [Ca2+]i, suggesting that noncyclooxygenase metabolites of arachidonic acid or cytochrome P-450 metabolites may participate in regulating the TRH-evoked entry of extracellular Ca2+. Both nordihydroguaiaretic acid and econazole showed a similar inhibition of the Ca2+ entry, as did SKF 96365, a compound previously shown to inhibit receptor-activated Ca2+ entry. We also showed that arachidonic acid per se increased [Ca2+]i, and acidified the cytosol in GH4C1 cells in a dose-dependent manner. The effects of arachidonic acid was reversed by addition of BSA to the cell suspension. The calcium entry and the activation of the metabolism of arachidonic acid may thus be important components of the TRH-evoked signal-transduction pathway in GH4C1 cells.

Lipopolysaccharides prime whole human blood and isolated neutrophils for the increased synthesis of 5-lipoxygenase products by enhancing arachidonic acid availability: involvement of the CD14 antigen

Stimulation of heparinized blood with 1 microM formyl-methionyl-leucyl-phenylalanine (FMLP) resulted in the formation of < 30 pmol/ml plasma of 5-lipoxygenase (5-LO) products. The preincubation of blood with 1 microgram/ml of lipopolysaccharide (LPS) (Escherichia coli 0111-B4) for 30 min before stimulation with FMLP resulted in the accumulation of 250-300 pmol of 5-LO products per ml plasma. The major products detected were leukotriene B4 and (5S)-hydroxy-6,8,11,14-eicosatetraenoic acid which were produced in equivalent amounts. The priming activity was detectable with as little as 1-10 ng LPS per ml blood and was optimal using 1-10 micrograms LPS/ml blood. The priming for 5-LO product synthesis was optimal after 20-30 min of preincubation with LPS and declined at preincubation times > 30 min. The priming effect of LPS was also observed using the complement fragment C5a or interleukin 8 as agonists. Polymorphonuclear leukocytes (PMN) and peripheral blood mononuclear cells accounted for 80 and 20% of the synthesis of 5-LO products, respectively. The ability of LPS to prime isolated PMN was dependent on the presence of plasma and was inhibited by the anti-CD14 antibody IOM2, indicating a CD14-dependent priming mechanism. The priming of whole blood with tumor necrosis factor alpha (TNF-alpha) and LPS was additive and the presence of mononuclear cells did not enhance the ability of LPS to prime PMN, indicating that the priming activity of LPS is independent of LPS-induced TNF-alpha synthesis. The mechanism by which LPS enhance 5-LO product synthesis in PMN was investigated. Treatment of PMN with LPS strongly enhanced the release of arachidonic acid after stimulation with FMLP. The release of arachidonic acid was optimal 2-3 min after stimulation with FMLP, attaining levels 5-15-fold greater than those observed in unprimed cells stimulated with FMLP. These results demonstrate that LPS dramatically increases the ability of blood to generate 5-LO products, and support the putative role of leukotrienes in pathological states involving LPS.

Thrombin-activated platelets promote leukotriene B4 synthesis in polymorphonuclear leucocytes stimulated by physiological agonists

1. The addition of 2 x 10(8) human platelets to 8 x 10(6) polymorphonuclear leucocytes (PMNL) incubated in presence of 2.5 u ml-1 thrombin and 0.1 microM N-formyl-Met-Leu-Phe (FMLP) (or C5a or PAF) led to enhancement of leukotriene B4 (LTB4) synthesis by the PMNL (measured by h.p.l.c. as 20-hydroxy- and 20-carboxy-LTB4) from 4 +/- 1 pmol (in absence of platelets) to 26 +/- 4 pmol (mean +/- s.e.mean, n = 9). Platelets and thrombin were both essential for the enhancement of LTB4 synthesis. 2. Platelets also caused enhancement of LTB4 synthesis from (30 +/- 12 to 134 +/- 25 pmol, n = 6) when PMNL pretreated with granulocyte-macrophage colony-stimulating factor were used in similar experiments. 3. Enhancement of LTB4 synthesis was also observed (from 5 +/- 1.5 to 26.5 +/- 5 pmol, n = 9) when the supernatants of thrombin-activated platelet suspensions were added to FMLP-stimulated PMNL. 4. Supernatants of platelet suspensions activated by thrombin in presence of cyclo-oxygenase and 12-lipoxygenase inhibitors led to greater enhancement (from 5 +/- 3 to 153.5 +/- 27.5 pmol, n = 3) of LTB4 synthesis by FMLP-stimulated PMNL, suggesting that arachidonic acid itself, rather than its metabolites was responsible for the effects of platelets. 5. Addition of arachidonic acid to FMLP-stimulated PMNL at a concentration comparable to that measured in thrombin-activated platelet supernatants (0.2 +/- 0.025 microM, n = 6) mimicked the effect of platelets or platelet supernatants on LTB4 synthesis in FMLP-activated PMNL. 6. The present data indicate that under conditions of cell activation by physiological agonists, platelets can significantly increase the formation of the proinflammatory compound LTB4 in PMNL by providing arachidonic acid. These data lend support to the concept that platelet-PMNL interactions could modulate the inflammatory process.

Inhibition of receptor-mediated calcium influx in T cells by unsaturated non-esterified fatty acids

The effect of omega-3, omega-6 and omega-9 unsaturated fatty acids (UFAs) on receptor-mediated Ca2+ entry was investigated in a T-cell line (JURKAT) by using anti-CD3 antibodies (OKT3) to induce intracellular Ca2+ [( Ca2+]i) increase and Ca2+ influx. All the UFAs, as well as Ni2+ ions and 12-O-tetradecanoylphorbol 13-acetate, decreased the OKT3-induced sustained [Ca2+]i increase to basal levels. Although non-esterified fatty acids activate protein kinase C (PKC) [McPhail, Clayton & Snyderman (1984) Science 224, 622-624; Murakami, Chan & Routtenberg (1986) J. Biol. Chem. 261, 15424-15429], studies using H-7 and analysis of the PKC-dependent phosphorylation of 19 and 80 kDa marker substrates ruled out the involvement of PKC in UFA-induced inhibition of Ca2+ entry. Flow-cytometry analysis showed that UFAs do not interfere with antibody-receptor binding. BSA (0.2%, w/v) reversed the effect of UFAs after these fatty acids have decreased the OKT3-induced [Ca2+]i increase to basal levels. The relevance of these findings and possible mechanisms for inhibition by UFAs of receptor-mediated Ca2+ influx were discussed.

The effect of ethanol on platelet function and vascular prostanoids

The present review will discuss the effects of ethanol on platelet function and vascular prostanoids. Whenever possible we have considered human studies because there are marked species differences in platelet function and vascular prostanoid release even in the absence of ethanol. Because of the specialised nature of some parts of the text, we have included brief introductions to help readers who are not familiar with this field.