Lack of endothelial dysfunction in patients under tacrolimus after orthotopic liver transplantation

Reduced Flow-Mediated Dilatation Is Not Related to COVID-19 Severity Three Months after Hospitalization for SARS-CoV-2 Infection

The coronavirus disease 2019 (COVID-19) pandemic has spread rapidly worldwide, with more than two million deaths. Evidence indicates the critical role of the vascular endothelium in its pathophysiology but, like potential changes in functional vasodilation, the vascular effect of SARS-CoV-2 at a given distance from the acute infection is largely unknown. We assessed brachial artery flow-mediated dilatation (FMD) in 27 COVID-19 patients needing conventional or intensive care unit hospitalization, three months after SARS-CoV-2 infection diagnosis and in nine age- and sex- matched control subjects. Interestingly, the FMD was lower in COVID-19 patients as compared to controls (8.2 (7.2–8.9) vs. 10.3 (9.1–11.7)); p = 0.002, and half of the hospitalized COVID-19 survivors presented with a reduced FMD < 8% at three months of COVID-19 onset. Impaired FMD was not associated with severe or critical SARS-CoV-2 infection, reflected by ICU hospitalization, total hospitalization duration, or severity of lung damage. In conclusion, reduced FMD is often observed even three months after hospitalization for SARS-CoV-2 infection, but such alteration predominantly appears to not be related to COVID-19 severity. Longer and larger follow-up studies will help to clarify the potential prognosis value of FMD among COVID-19 patients, as well as to further determine the mechanisms involved.

Effects of a High Fat Meal Associated with Water, Juice, or Champagne Consumption on Endothelial Function and Markers of Oxidative Stress and Inflammation in Young, Healthy Subjects

Endothelial dysfunction (ED), often linked to hypertriglyceridemia, is an early step of atherosclerosis. We investigated, in a randomized cross-over study, whether high-fat meal (HFM)-induced ED might be reduced by fruit juice or champagne containing polyphenols. Flow-mediated dilatation (FMD) and biological parameters (lipid profile, glycemia, inflammation, and oxidative stress markers) were determined before and two and three hours after the HFM in 17 healthy young subjects (24.6 ± 0.9 years) drinking water, juice, or champagne. Considering the entire group, despite significant hypertriglyceridemia (from 0.77 ± 0.07 to 1.41 ± 0.18 mmol/L, p < 0.001) and a decrease in Low Density Lipoprotein (LDL), the FMD was not impaired. However, the FMD decreased in 10 subjects (from 10.73 ± 0.95 to 8.13 ± 0.86 and 8.07 ± 1.16%; p < 0.05 and p < 0.01; 2 and 3 h, respectively, after the HFM), without concomitant change in concentration reactive protein or reactive oxygen species, but with an increase in glycemia. In the same subjects, the FMD did not decrease when drinking juice or champagne. In conclusion, HFM can impair the endothelial function in healthy young subjects. Fruit juice, rich in anthocyanins and procyanidins, or champagne, rich in simple phenolic acids, might reduce such alterations, but further studies are needed to determine the underlying mechanisms, likely involving polyphenols.

Cardiovascular disease after liver transplantation: When, What, and Who Is at Risk

The evolution of metabolic and cardiovascular disease (CVD) complications after liver transplantation (LT) is poorly characterized. We aim to illustrate the prevalence of obesity and metabolic syndrome (MS), define the cumulative incidence of CVD, and characterize risk factors associated with these comorbidities after LT. A retrospective review of 455 consecutive LT recipients from 1999 to 2004 with an 8- to 12-year follow-up was performed. Obesity increased from 23.8% (4 months) to 40.8% (3 years) after LT. Increase in body mass index predicted MS at 1 year after LT (odds ratio, 1.1; P < 0.001, per point). CVD developed in 10.6%, 20.7%, and 30.3% of recipients within 1, 5, and 8 years, respectively. Age, diabetes, hypertension, glomerular filtration rate < 60 mL/minute, prior CVD, ejection fraction < 60%, left ventricular hypertrophy, and serum troponin (TN) > 0.07 ng/mL were associated with CVD on univariate analysis. Age (hazard ratio [HR], 1.03; 95% confidence interval [CI], 1.01-1.06; P = 0.019), diabetes (HR, 1.78; 95% CI, 1.09-2.92; P = 0.022), prior history of CVD (HR, 2.46; 95% CI, 1.45-4.16; P < 0.001), and serum TN > 0.07 ng/mL (HR, 1.98; 95% CI, 1.23-3.18; P = 0.005) were independently associated with CVD in the long term. Smoking history (ever), sex, hyperlipidemia, and serum ferritin levels were not predictive of CVD. Tacrolimus use versus noncalcineurin-based immunosuppression (HR, 0.26; 95% CI, 0.14-0.49; P < 0.001) was associated with reduced risk of CVD but not versus cyclosporine (HR, 0.67; 95% CI, 0.30-1.49; P = 0.322). CVD is common after LT. Independent of MS, more data are needed to identify nonconventional risk factors and biomarkers like serum TN. Curbing weight gain in the early months after transplant may impact MS and subsequent CVD in the long term.

Role of vasodilation during normothermic machine perfusion of DCD porcine livers

INTRODUCTION

Normothermic machine perfusion (NMP) of the liver is a promising preservation modality that holds the potential to better preserve and even repair marginal grafts. In spite of several literature studies showing the benefits of NMP over cold storage, there is paucity of data regarding the mechanisms involved in the optimization of the microcirculation during preservation of these organs. We present our data on the impact of different vasodilators on DCD porcine livers preserved with NMP.

MATERIALS AND METHODS

Livers from 15 female Yorkshire pigs (30-40 kg) were subjected to 60 min of WIT followed by 10 h of NMP. Group PC (n = 5) received a prostacyclin analog (epoprostenol sodium) and the AD group (n = 5) received adenosine, whereas group WV (n = 5) was perfused without using any vasodilator. Liver function was assessed by measuring, liver enzyme levels, bile production rate, and histological analysis.

RESULTS

At the end of perfusion, the PC group showed significantly lower AST (583 ± 62 vs. 2471 ± 745 and 2547 ± 690 IU/dl), ALT (41 ± 3 vs. 143 ± 28 and 111 ± 25 IU/dl) and LDH (840 ± 85 vs. 2756 ± 408 and 4153 ± 1569 IU/dl) levels compared to the AD and WV groups respectively (p<0.05). Bile production was significantly higher in the PC group compared to the AD group and WV, respectively (95 ± 9 vs. 37 ± 10 and 45 ± 18ml) (p<0.05). Histological samples of the PC group showed preserved hepatic architecture while those of the AD group and WV showed sinusoidal dilatation, architectural distortion, and profuse intraparenchymal hemorrhage.

CONCLUSIONS

Maintenance of optimal microcirculatory homeostasis using proper vasodilators is a key factor in NMP of DCD livers.

Down-regulation of the ATP-binding cassette transporter 2 (Abca2) reduces amyloid-β production by altering Nicastrin maturation and intracellular localization

Clinical, pharmacological, biochemical, and genetic evidence support the notion that alteration of cholesterol homeostasis strongly predisposes to Alzheimer disease (AD). The ATP-binding cassette transporter-2 (Abca2), which plays a role in intracellular sterol trafficking, has been genetically linked to AD. It is unclear how these two processes are related. Here we demonstrate that down-regulation of Abca2 in mammalian cells leads to decreased amyloid-β (Aβ) generation. In vitro studies revealed altered γ-secretase complex formation in Abca2 knock-out cells due to the altered levels, post-translational modification, and subcellular localization of Nicastrin. Reduced Abca2 levels in mammalian cells in vitro, in Drosophila melanogaster and in mice resulted in altered γ-secretase processing of APP, and thus Aβ generation, without affecting Notch cleavage.