Acute liver injury in COVID-19 patients hospitalized in the intensive care unit: Narrative review

In recent years, humanity has been confronted with a global pandemic due to coronavirus disease 2019 (COVID-19), which has caused an unprecedented health and economic crisis worldwide. Apart from the respiratory symptoms, which are considered the principal manifestations of COVID-19, it has been recognized that COVID-19 constitutes a systemic inflammatory process affecting multiple organ systems. Across the spectrum of organ involvement in COVID-19, acute liver injury (ALI) has been gradually gaining increasing attention by the international scientific community. COVID-19 associated liver impairment can affect a considerable proportion of COVID-19 patients and seems to correlate with the severity of the disease course. Indeed, COVID-19 patients hospitalized in the intensive care unit (ICU) run a greater risk of developing ALI due to the severity of their clinical condition and in the context of multi-organ failure. The putative pathophysiological mechanisms of COVID-19 induced ALI in ICU patients remain poorly understood and appear to be multifactorial in nature. Several theories have been proposed to explain the occurrence of ALI in the ICU setting, such as hypoperfusion and ischemia due to hemodynamic instability, passive liver congestion as a result of congestive heart failure, ischemia-reperfusion injury, hypoxia due to respiratory failure, mechanical ventilation itself, sepsis and septic shock, cytokine storm, endotheliitis with concomitant coagulopathy, drug-induced liver injury, parenteral nutrition and direct cytopathic viral effect. It should be noted that no specific therapy for COVID-19 induced ALI exists. Therefore, the therapeutic approach lies in preventive measures and is exclusively supportive once ALI ensues. The aim of the current review is to scrutinize the existing evidence on COVID-19 associated ALI in ICU patients, explore its clinical implications, shed light on the underlying pathophysiological mechanisms and propose potential therapeutic approaches. Ongoing research on the particular scientific field will further elucidate the pathophysiology behind ALI and address unresolved issues, in the hope of mitigating the tremendous health consequences imposed by COVID-19 on ICU patients.     

The diagnosis of Gestational Diabetes Mellitus and its impact on In Vitro Fertilization pregnancies. A pilot study

BackgroundIn Vitro Fertilization (IVF) is increasingly becoming a necessary mode of reproduction. This high risk group is prone to Gestational Diabetes Mellitus (GDM) which further exposes these pregnancies to an increased risk of adverse outcomes. In light of the limited data in the current literature, further investigation is needed regarding the time of GDM diagnosis in IVF pregnancies as well as the outcome of IVF pregnancies complicated by GDM.MethodsIn this three center pilot cross sectional study, the data of 101 singleton IVF pregnancies complicated by GDM were analyzed. Prompt GDM diagnosis in IVF pregnancies was accomplished by self-blood glucose monitoring (SMBG) from the first antenatal visit and confirmed by an OGTT. To evaluate pregnancy outcome, maternal and fetal complications in the 101 GDM IVF group was compared to 101 IVF as well as 101 spontaneous conceptions (SC). The three groups were matched by age. The effect of demographic and glycemic parameters on the outcome of GDM IVF pregnancies was investigated.ResultsGDM diagnosis was made before the 24th week in 37.6% of the GDM IVF group. The week of delivery was earlier for the GDM IVF group (37 ± 1.7) relative to the IVF (37.9 ± 0.9, p < 0.001) and the SC group (38.1 ± 0.8, p < 0.001). GDM IVF pregnancies exhibited greater preeclampsia rates and 84.8% underwent caesarian section. No significant difference regarding LGA and SGA birth weights was found. Complications of GDM IVF pregnancies were associated with the 1-h postprandial BG (r = 0.267, p = 0.007).ConclusionGDM screening in IVF pregnancies may be considered earlier than the 24th week. IVF pregnancies affected by GDM are prone to increased maternal and fetal complications which are associated with 1-h postprandial BG.     

Prevalence of hemochromatosis gene (HFE) mutations in Greece

The frequencies of the hereditary hemochromatosis gene (HFE) mutations C282Y and H63D vary between different populations. There are a limited number of reports regarding the frequency of these mutations in populations of southeastern Europe. Two hundred and sixty-four adult individuals of Greek origin were examined for the C282Y and H63D mutations to determine the allele and genotype frequencies. The HFE gene region of DNA samples extracted from peripheral leukocytes was amplified by the polymerase chain reaction. Restriction enzyme analysis was performed using RSAI for C282Y and MBOI for H63D. None of the 264 individuals carried the mutation C282Y. Forty-three individuals (16.2%) were heterozygous carriers of the H63D allele and 2 were homozygous for this mutation (0.75%). The overall H63D allele prevalence is thus estimated at 8.9%. HFE mutation frequencies were low in the population studied and this may explain, in part, the relative rarity of clinical cases of hereditary hemochromatosis in Greece.     

Coincidental Malabsorption of Lactose, Fructose, and Sorbitol Ingested at Low Doses Is Not Common in Normal Adults

Normal subjects may incompletely absorb either lactose, fructose, or sorbitol and may therefore have abdominal symptoms. The frequency of coincidental malabsorption of these sugars is not known. This is clinically important, since we often ingest them during the same day and malabsorption may cause abdominal symptoms. To shed light on this issue we studied 32 normal subjects. Volunteers drank in random order the following solutions: 20 g lactulose, 50 g sucrose, 50 and 25 g lactose, 50 and 25 g fructose, 20 and 10 g sorbitol. Semiquantitative carbohydrate malabsorption was estimated with lactulose standards. Frequency of 50-g lactose (69%), 50-g fructose (81%), and 20-g sorbitol (84%) malabsorption was not significantly different (P = 0.3). The estimated median fraction of the ingested high dose malabsorbed was 42, 19, and 68% for lactose, fructose, and sorbitol, respectively. At low challenging doses, 63% of the volunteers absorbed two of three or all three sugars, and 88% were asymptomatic to two or all three sugars. In conclusion, the frequency of coincidental malabsorption of lactose, fructose, and sorbitol and intolerance to these sugars is not common, when normal adults ingest them at low doses.     

Reengineered salivary glands are stable endogenous bioreactors for systemic gene therapeutics

The use of critical-for-life organs (e.g., liver or lung) for systemic gene therapeutics can lead to serious safety concerns. To circumvent such issues, we have considered salivary glands (SGs) as an alternative gene therapeutics target tissue. Given the high secretory abilities of SGs, we hypothesized that administration of low doses of recombinant adeno-associated virus (AAV) vectors would allow for therapeutic levels of transgene-encoded secretory proteins in the bloodstream. We administered 10(9) particles of an AAV vector encoding human erythropoietin (hEPO) directly to individual mouse submandibular SGs. Serum hEPO reached maximum levels 8-12 weeks after gene delivery and remained relatively stable for 54 weeks (longest time studied). Hematocrit levels were similarly increased. Moreover, these effects proved to be vector dose-dependent, and even a dosage as low as 10(8) particles per animal led to significant increases in hEPO and hematocrit levels. Vector DNA was detected only within the targeted SGs, and levels of AAV copies within SGs were highly correlated with serum hEPO levels (r = 0.98). These results show that SGs appear to be promising targets with potential clinical applicability for systemic gene therapeutics.     

A 10-year aerobiological study (1994-2003) in the Mediterranean island of Crete, Greece: trees, aerobiologic data, and botanical and clinical correlations.

Pollen grains from the plant cover of a given area participate largely in the composition of aeroflora (pollen and molds) of this area. Association of allergic respiratory disorders with concentration of allergenic particles in the atmosphere is well documented, and aerobiologic studies are of great relevance. A 10-year volumetric aerobiologic study was conducted in the city of Heraklion, located in the center of the north-shore of the island of Crete, Greece. Main allergenic families and genera encountered were, in descending order of frequency Oleaceae, Quercus, Platanaceae, Cupressaceae, Pinaceae, Populus, Moraceae, and Corylaceae. Concentrations noted for most of these aeroallergens were much lower than those reported from other European regions. In parallel, an atopic population of 576 individuals, exhibiting allergic symptoms mainly of the respiratory tract were subjected to a battery of skin-prick tests. A fair degree of agreement between total pollen counts and positive skin-prick test frequencies for the families of Oleaceae, Platanaceae, and Cupressaceae was noted. On the contrary a poor degree of concordance was noted for the rest of the families and genera.     

Tamoxifen induced hepatotoxicity in breast cancer patients with pre-existing liver steatosis: the role of glucose intolerance

OBJECTIVE: Tamoxifen induced hepatotoxicity has not been investigated in breast cancer patients with pre-existing liver steatosis. The aim of our study was to investigate the most common predisposing factors for non-alcoholic fatty liver disease in breast cancer patients with liver steatosis, treated with adjuvant tamoxifen therapy, in order to evaluate their role in the appearance of tamoxifen induced hepatotoxicity. METHODS: Clinical and laboratory evaluation, including an oral glucose tolerance test, was done in 60 women with breast cancer and liver steatosis before the beginning of adjuvant tamoxifen treatment and every 6 months during treatment. Tamoxifen induced hepatotoxicity was defined as abnormal liver function tests during tamoxifen treatment whereas these test results were below the normal range at baseline control. Statistical evaluation of data was performed using parametric methodology (the chi-squared test, and Student's t-test, P < 0.05). RESULTS: Twenty-six patients (43.3%) exhibited tamoxifen induced hepatotoxicity (group A) whereas 34 (56.7%) did not (group B). The mean overall follow-up period for the whole group was 37.5 months (SD 27.8, range 6-120 months) and did not differ between the two groups (P = 0.055). There was significant statistical difference in body mass index (BMI) and baseline fasting glucose, cholesterol and triglyceride levels between the two groups. Eighteen of 26 patients (69.2%) from group A had impaired glucose tolerance compared with only 8/34 patients (23.5%) from group B (P < 0.001), a finding observed even in BMI matched patients from the two groups (62.5% vs 12.5%, P = 0.002). CONCLUSIONS: Tamoxifen induced hepatotoxicity is observed in a great proportion of breast cancer patients with pre-existing liver steatosis, especially those with higher BMI and higher glucose and lipid levels at baseline control. Glucose intolerance before the beginning of tamoxifen treatment seems to be a predictor of the hepatotoxicity, unrelated to baseline BMI.     

Regulation of intercellular biomolecule transfer–driven tumor angiogenesis and responses to anticancer therapies

Intercellular biomolecule transfer (ICBT) between malignant and benign cells is a major driver of tumor growth, resistance to anticancer therapies, and therapy-triggered metastatic disease. Here we characterized cholesterol 25-hydroxylase (CH25H) as a key genetic suppressor of ICBT between malignant and endothelial cells (ECs) and of ICBT-driven angiopoietin-2–dependent activation of ECs, stimulation of intratumoral angiogenesis, and tumor growth. Human CH25H was downregulated in the ECs from patients with colorectal cancer and the low levels of stromal CH25H were associated with a poor disease outcome. Knockout of endothelial CH25H stimulated angiogenesis and tumor growth in mice. Pharmacologic inhibition of ICBT by reserpine compensated for CH25H loss, elicited angiostatic effects (alone or combined with sunitinib), augmented the therapeutic effect of radio-/chemotherapy, and prevented metastatic disease induced by these regimens. We propose inhibiting ICBT to improve the overall efficacy of anticancer therapies and limit their prometastatic side effects.     

Inhibition of indoleamine 2,3-dioxygenase in mixed lymphocyte reaction affects glucose influx and enzymes involved in aerobic glycolysis and glutaminolysis in alloreactive T-cells

Indoleamine 2,3-dioxygenase (IDO) suppresses adaptive immunity. T-cell proliferation and differentiation to effector cells require increased glucose consumption, aerobic glycolysis and glutaminolysis. The effect of IDO on the above metabolic pathways was evaluated in alloreactive T-cells. Mixed lymphocyte reaction (MLR) in the presence or not of the IDO inhibitor, 1-methyl-dl-tryptophan (1-MT), was used. In MLRs, 1-MT decreased tryptophan consumption, increased cell proliferation, glucose influx and lactate production, whereas it decreased tricarboxylic acid cycle activity. In T-cells, from the two pathways that could sense tryptophan depletion, i.e. general control nonrepressed 2 (GCN2) kinase and mammalian target of rapamycin complex 1, 1-MT reduced only the activity of the GCN2 kinase. Additionally 1-MT treatment of MLRs altered the expression and/or the phosphorylation state of glucose transporter-1 and of key enzymes involved in glucose metabolism and glutaminolysis in alloreactive T-cells in a way that favors glucose influx, aerobic glycolysis and glutaminolysis. Thus in alloreactive T-cells, IDO through activation of the GCN2 kinase, decreases glucose influx and alters key enzymes involved in metabolism, decreasing aerobic glycolysis and glutaminolysis. Acting in such a way, IDO could be considered as a constraining factor for alloreactive T-cell proliferation and differentiation to effector T-cell subtypes.