Down-Regulation of the Mineralocorticoid Receptor (MR) and Up-Regulation of Hydroxysteroid 11-Beta Dehydrogenase Type 2 (HSD11B2) Isoenzyme in Critically Ill Patients.

Objective: The mineralocorticoid receptor (MR) has two ligands, aldosterone and cortisol. Hydroxysteroid 11-beta dehydrogenase (HSD11B) isoenzymes regulate which ligand will bind to MR. In this study we aimed to evaluate the expression of the MR and the HSD11B isozymes in peripheral polymorphonuclear cells (PMNs) in critical illness for a 13-day period.Design: Prospective studySetting: One multi-disciplinary intensive care unit (ICU)Participants: Forty-two critically ill patientsMethods: Messenger RNA (mRNA) expression of MR, HSD11B1, and HSD11B2, aldosterone levels, and plasma renin activity (PRA) were measured in 42 patients on ICU admission and on days 4, 8, and 13. Twenty-five age and sex-matched healthy subjects were used as controls.Results: Compared to healthy controls, MR expression in critically ill patients was lower during the entire study period. HSD11B1 expression was also lower, while HSD11B2 expression was higher. In patients, PRA, aldosterone, the aldosterone:renin ratio, and cortisol remained unaltered during the study period.Conclusion: Our results suggest that, in our cohort of critically ill patients, local endogenous cortisol availability is diminished, pointing towards glucocorticoid resistance. Aldosterone probably occupies the MR, raising the possibility that PMNs might be useful to study to gain insights into MR functionality during pathological states.

Endotheliopathy in Acute COVID-19 and Long COVID.

The pulmonary endothelium is a highly regulated organ that performs a wide range of functions under physiological and pathological conditions. Since endothelial dysfunction has been demonstrated to play a direct role in sepsis and acute respiratory distress syndrome, its role in COVID-19 has also been extensively investigated. Indeed, apart from the COVID-19-associated coagulopathy biomarkers, new biomarkers were recognised early during the pandemic, including markers of endothelial cell activation or injury. We systematically searched the literature up to 10 March 2023 for studies examining the association between acute and long COVID-19 severity and outcomes and endothelial biomarkers.

Aquaporin Expression and Regulation in Clinical and Experimental Sepsis.

Sepsis is an inflammatory disorder caused by the host's dysfunctional response to infection. Septic patients present diverse clinical characteristics, and in the recent years, it has been the main cause of death in intensive care units (ICU). Aquaporins, membrane proteins with a role in water transportation, have been reported to participate in numerous biological processes. Their role in sepsis progression has been studied extensively. This review aims to examine recent literature on aquaporin expression and regulation in clinical sepsis, as well as established experimental models of sepsis. We will present how sepsis affects aquaporin expression at the molecular and protein level. Moreover, we will delve into the importance of aquaporin regulation at transcriptional, post-transcriptional, translational, and post-translational levels in sepsis by presenting data on aquaporin regulation by non-coding RNAs and selected chemical molecules. Finally, we will focus on the importance of aquaporin single-nucleotide polymorphisms in the setting of sepsis.

Investigation of Serum Endocan Levels and Age in Critical Inflammatory Conditions.

Aging negatively affects the endothelium. Endocan (ESM-1), an endothelium-derived soluble proteoglycan, participates in fundamental biological processes of endothelial cells. We aimed to examine the role of endothelial dysfunction and age in poor outcomes in critical illness. ESM-1 levels were measured in the sera of mechanically ventilated critically ill patients, including COVID-19, non-septic, and septic patients. The 3 patient cohorts were divided based on age (≥65 and <65). Critically ill COVID-19 patients had statistically higher ESM-1 levels compared to critically ill septic and non-septic patients. Only in critically ill septic patients were ESM-1 levels higher in older compared to younger patients. Finally, the age-subgrouped patients were further subdivided based on intensive care unit (ICU) outcome. ESM-1 levels were similar in COVID-19 survivors and non-survivors, irrespective of age. Interestingly, only for the younger critically ill septic patients, non-survivors had higher ESM-1 levels compared to survivors. In the non-septic survivors and non-survivors, ESM-1 levels remained unaltered in the younger patients and tended to be higher in the elderly. Even though endocan has been recognized as an important prognostic biomarker in critically ill patients with sepsis, in our patient cohort, increased age, as well as the extent of endothelial dysfunction, seemed to affect its prognostic ability.

Increased Levels of Galectin-3 in Critical COVID-19.

Severe COVID-19 is related to hyperinflammation and multiple organ injury, including respiratory failure, thus requiring intensive care unit (ICU) admission. Galectin-3, a carbohydrate-binding protein exhibiting pleiotropic effects, has been previously recognized to participate in inflammation, the immune response to infections and fibrosis. The aim of this study was to evaluate the relationship between galectin-3 and the clinical severity of COVID-19, as well as assess the prognostic accuracy of galectin-3 for the probability of ICU mortality. The study included 235 COVID-19 patients with active disease, treated in two different Greek hospitals in total. Our results showed that median galectin-3 serum levels on admission were significantly increased in critical COVID-19 patients (7.2 ng/mL), as compared to the median levels of patients with less severe disease (2.9 ng/mL, p = 0.003). Galectin-3 levels of the non-survivors hospitalized in the ICU were significantly higher than those of the survivors (median 9.1 ng/mL versus 5.8 ng/mL, p = 0.001). The prognostic accuracy of galectin-3 for the probability of ICU mortality was studied with a receiver operating characteristic (ROC) curve and a multivariate analysis further demonstrated that galectin-3 concentration at hospital admission could be assumed as an independent risk factor associated with ICU mortality. Our results were validated with galectin-3 measurements in a second patient cohort from a different Greek university hospital. Our results, apart from strongly confirming and advancing previous knowledge with two patient cohorts, explore the possibility of predicting ICU mortality, which could provide useful information to clinicians. Therefore, galectin-3 seems to establish its involvement in the prognosis of hospitalized COVID-19 patients, suggesting that it could serve as a promising biomarker in critical COVID-19.

The Interplay between Aquaporin-1 and the Hypoxia-Inducible Factor 1α in a Lipopolysaccharide-Induced Lung Injury Model in Human Pulmonary Microvascular Endothelial Cells.

Aquaporin-1 (AQP1), a water channel, and the hypoxia-inducible factor 1α (HIF1A) are implicated in acute lung injury responses, modulating among others pulmonary vascular leakage. We hypothesized that the AQP1 and HIF1A systems interact, affecting mRNA, protein levels and function of AQP1 in human pulmonary microvascular endothelial cells (HPMECs) exposed to lipopolysaccharide (LPS). Moreover, the role of AQP1 in apoptosis and wound healing progression was examined. Both AQP1 mRNA and protein expression levels were higher in HPMECs exposed to LPS compared to untreated HPMECs. However, in the LPS-exposed HIF1A-silenced cells, the mRNA and protein expression levels of AQP1 remained unaltered. In the permeability experiments, a statistically significant volume increase was observed at the 360 s time-point in the LPS-exposed HPMECs, while LPS-exposed HIF1A-silenced HPMECs did not exhibit cell swelling, implying a dysfunctional AQP1. AQP1 did not seem to affect cell apoptosis yet could interfere with endothelial migration and/or proliferation. Based on our results, it seems that HIF1A silencing negatively affects AQP1 mRNA and protein expression, as well as AQP1 function, in the setting of lung injury.

Autotaxin Has a Negative Role in Systemic Inflammation.

The pathogenesis of sepsis involves complex interactions and a systemic inflammatory response leading eventually to multiorgan failure. Autotaxin (ATX, ENPP2) is a secreted glycoprotein largely responsible for the extracellular production of lysophosphatidic acid (LPA), which exerts multiple effects in almost all cell types through its at least six G-protein-coupled LPA receptors (LPARs). Here, we investigated a possible role of the ATX/LPA axis in sepsis in an animal model of endotoxemia as well as in septic patients. Mice with 50% reduced serum ATX levels showed improved survival upon lipopolysaccharide (LPS) stimulation compared to their littermate controls. Similarly, mice bearing the inducible inactivation of ATX and presenting with >70% decreased ATX levels were even more protected against LPS-induced endotoxemia; however, no significant effects were observed upon the chronic and systemic transgenic overexpression of ATX. Moreover, the genetic deletion of LPA receptors 1 and 2 did not significantly affect the severity of the modelled disease, suggesting that alternative receptors may mediate LPA effects upon sepsis. In translation, ATX levels were found to be elevated in the sera of critically ill patients with sepsis in comparison with their baseline levels upon ICU admission. Therefore, the results indicate a role for ATX in LPS-induced sepsis and suggest possible therapeutic benefits of pharmacologically targeting ATX in severe, systemic inflammatory disorders.

Increased Glucocorticoid Receptor Alpha Expression and Signaling in Critically Ill Coronavirus Disease 2019 Patients.

OBJECTIVES: Critical illness is characterized by increased serum cortisol concentrations and bioavailability resulting from the activation of the hypothalamic-pituitary-adrenal axis, which constitutes an essential part of the stress response. The actions of glucocorticoids are mediated by a ubiquitous intracellular receptor protein, the glucocorticoid receptor. So far, data on coronavirus disease 2019 and glucocorticoid receptor alpha expression are lacking. DESIGN: Prospective observational study. SETTING: One academic multidisciplinary ICU. SUBJECTS: Twenty-six adult coronavirus disease 2019 patients; 33 adult noncoronavirus disease 2019 patients, matched for age, sex, and disease severity, constituted the control group. All patients were steroid-free. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Glucocorticoid receptor alpha, glucocorticoid-inducible leucine zipper expression, and serum cortisol were measured on ICU admission. In coronavirus disease 2019 patients, glucocorticoid receptor alpha and glucocorticoid-inducible leucine zipper messenger RNA expression were upregulated (4.7-fold, p < 0.01 and 14-fold, p < 0.0001, respectively), and cortisol was higher (20.3 vs 14.3 µg/dL, p < 0.01) compared with the control group. CONCLUSIONS: ICU coronavirus disease 2019 patients showed upregulated glucocorticoid receptor alpha and glucocorticoid-inducible leucine zipper expression, along with cortisol levels, compared with ICU noncoronavirus disease 2019 patients. Thus, on ICU admission, critical coronavirus disease 2019 appears to be associated with hypercortisolemia, and increased synthesis of glucocorticoid receptor alpha and induced proteins.

Pituitary-Adrenal Responses and Glucocorticoid Receptor Expression in Critically Ill Patients with COVID-19.

The hypothalamus-pituitary-adrenal (HPA) axis was described as the principal component of the stress response 85 years ago, along with the acute-phase reaction, and the defense response at the tissue level. The orchestration of these processes is essential since systemic inflammation is a double-edged sword; whereas inflammation that is timely and of appropriate magnitude is beneficial, exuberant systemic inflammation incites tissue damage with potentially devastating consequences. Apart from its beneficial cardiovascular and metabolic effects, cortisol exerts a significant immunoregulatory role, a major attribute being that it restrains the excessive inflammatory reaction, thereby preventing unwanted tissue damage. In this review, we will discuss the role of the HPA axis in the normal stress response and in critical illness, especially in critically ill patients with coronavirus disease 2019 (COVID-19). Finally, a chapter will be dedicated to the findings from clinical studies in critical illness and COVID-19 on the expression of the mediator of glucocorticoid actions, the glucocorticoid receptor (GCR).

Increased Autotaxin Levels in Severe COVID-19, Correlating with IL-6 Levels, Endothelial Dysfunction Biomarkers, and Impaired Functions of Dendritic Cells.

Autotaxin (ATX; ENPP2) is a secreted lysophospholipase D catalyzing the extracellular production of lysophosphatidic acid (LPA), a pleiotropic signaling phospholipid. Genetic and pharmacologic studies have previously established a pathologic role for ATX and LPA signaling in pulmonary injury, inflammation, and fibrosis. Here, increased ENPP2 mRNA levels were detected in immune cells from nasopharyngeal swab samples of COVID-19 patients, and increased ATX serum levels were found in severe COVID-19 patients. ATX serum levels correlated with the corresponding increased serum levels of IL-6 and endothelial damage biomarkers, suggesting an interplay of the ATX/LPA axis with hyperinflammation and the associated vascular dysfunction in COVID-19. Accordingly, dexamethasone (Dex) treatment of mechanically ventilated patients reduced ATX levels, as shown in two independent cohorts, indicating that the therapeutic benefits of Dex include the suppression of ATX. Moreover, large scale analysis of multiple single cell RNA sequencing datasets revealed the expression landscape of ENPP2 in COVID-19 and further suggested a role for ATX in the homeostasis of dendritic cells, which exhibit both numerical and functional deficits in COVID-19. Therefore, ATX has likely a multifunctional role in COVID-19 pathogenesis, suggesting that its pharmacological targeting might represent an additional therapeutic option, both during and after hospitalization.

Glycemia, Beta-Cell Function and Sensitivity to Insulin in Mildly to Critically Ill Covid-19 Patients.

Background and objectives: Critically and non-critically ill patients with SARS-CoV-2 infection (Covid-19) may present with higher-than-expected glycemia, even in the absence of diabetes. With this study we aimed to assess glucose, glycemic gap (GlyG) and insulin secretion/sensitivity measures in patients with Covid-19. Materials and Methods: We studied, upon admission, 157 patients with Covid-19 (84: in wards and 73: in intensive care units; ICU); 135 had no history of diabetes. We measured blood glucose upon admission as well as glycated hemoglobin (A1c), plasma insulin and C-peptide. We calculated the GlyG and the Homeostasis Model Assessment 2 (HOMA2) estimates of steady state beta cell function (HOMA2%B) and insulin sensitivity (HOMA2%S). Statistical assessment was done with analysis or the Kruskal-Wallis test. Results: Compared to patients in the wards without diabetes, patients with diabetes in the wards, as well as patients in the ICU (without or with diabetes) had higher admission glycemia. The GlyG was significantly higher in patients without diabetes in the ICU compared to patients without diabetes in the wards, while HOMA2%B based on glucose and insulin was significantly higher in the ICU patients compared to patients in the wards. Of all the parameters, HOMA2%S based on C-peptide/glucose was higher in survivors (n = 133). Conclusions: In our series of patients with Covid-19, a substantial number of patients with and without diabetes had admission hyperglycemia and those who were critically ill may have had compromised insulin secretion and lowered sensitivity to insulin. These findings lend credence to reports of association between Covid-19 and hyperglycemia/secondary diabetes.

Knockdown of bone morphogenetic protein type II receptor leads to decreased aquaporin 1 expression and function in human pulmonary microvascular endothelial cells.

Bone morphogenetic proteins (BMPs) were once considered only to have a role in bone formation. It is now known that they have pivotal roles in other organ diseases, including heritable pulmonary arterial hypertension (PAH), where genetic mutations in the type II BMP receptor (BMPR2) are the commonest cause of receptor dysfunction. However, it has also recently been demonstrated that aquaporin 1 (Aqp1) dysfunction may contribute to PAH, highlighting that PAH development may involve more than one pathogenic pathway. Whether reduction in BMPR2 affects Aqp1 is unknown. We therefore studied Aqp1 in BMPR2-silenced human pulmonary microvascular endothelial cells (HPMECs). We demonstrated reduced Aqp1 mRNA, protein, and function in the BMPR2-silenced cells. Additionally, BMPR2-silenced cells exhibited lower expression of BMP-signaling molecules. In conclusion, decreased BMPR2 appears to affect Aqp1 at the mRNA, protein, and functional levels. This observation may identify a contributory mechanism for PAH.

Endothelial Damage in Acute Respiratory Distress Syndrome.

The pulmonary endothelium is a metabolically active continuous monolayer of squamous endothelial cells that internally lines blood vessels and mediates key processes involved in lung homoeostasis. Many of these processes are disrupted in acute respiratory distress syndrome (ARDS), which is marked among others by diffuse endothelial injury, intense activation of the coagulation system and increased capillary permeability. Most commonly occurring in the setting of sepsis, ARDS is a devastating illness, associated with increased morbidity and mortality and no effective pharmacological treatment. Endothelial cell damage has an important role in the pathogenesis of ARDS and several biomarkers of endothelial damage have been tested in determining prognosis. By further understanding the endothelial pathobiology, development of endothelial-specific therapeutics might arise. In this review, we will discuss the underlying pathology of endothelial dysfunction leading to ARDS and emerging therapies. Furthermore, we will present a brief overview demonstrating that endotheliopathy is an important feature of hospitalised patients with coronavirus disease-19 (COVID-19).

Decreased glucocorticoid receptor expression during critical illness.

INTRODUCTION: In critically ill patients, the hypothalamic-pituitary-adrenal axis is activated, resulting in increased serum cortisol concentrations. However, in some patients, especially those with sepsis, cortisol levels are relatively low for the degree of illness severity. Therefore, in the present project, we aim to characterize the time course of glucocorticoid receptor (GCR) alpha and beta expression in peripheral polymorphonuclear cells of critically ill septic or nonseptic patients using real-time PCR. DESIGN: A prospective observational study conducted on 32 critically ill adults not receiving steroids, in a university-affiliated, multidisciplinary intensive care unit (ICU). Blood samples were collected for measurement of glucocorticoid receptor expression within 24-48 hours of admission to the ICU and at days 4, 8 and 13 after admission, reflecting the acute and chronic phase of the illness. RESULTS: During ICU stay, patients expressed over time reduced levels of both GCR-α and GCR-ß mRNA. More specifically, GCR-α mRNA expression was decreased fourfold 4 days after admission (P < 0.0001) and remained low up to 2 weeks after admission (P < 0.001). On the other hand, GCR-ß mRNA levels remained stable shortly after admission, but approx. one week after admission, its levels decreased threefold (P < 0.01) and remained reduced up to 2 weeks after admission (P < 0.001). DISCUSSION: Our results suggest that critically ill patients have highly variable expression of alpha and beta GCR, and moreover, the levels of both receptors decrease during ICU stay. Taken together, these might explain the differential responsiveness of patients to exogenous steroid administration or to endogenous cortisol secretion.

Elevated biomarkers of endothelial dysfunction/activation at ICU admission are associated with sepsis development.

Widespread endothelial activation and dysfunction often precede clinical sepsis. Several endothelium-related molecules have been investigated as potential biomarkers for early diagnosis and/or prognosis of sepsis, providing different results depending on study designs. Such factors include endothelial adhesion molecules like E- and P-selectin, and the intercellular adhesion molecule-1, vascular endothelial cadherin, growth factors such as Angiopoietin-1 and -2 and vascular endothelial growth factor, as well as von Willebrand factor antigen. We sought to investigate whether circulating biomarkers of endothelial activation/dysfunction measured at ICU admission are associated with subsequent sepsis development. Eighty-nine critically-ill patients admitted to a general ICU who met no sepsis criteria were studied. Plasma or serum levels of the above-mentioned endothelium-derived molecules were measured during the first 24h post ICU; acute physiology and chronic health evaluation (APACHE) II and sequential organ failure assessment (SOFA) scores, age, sex, diagnostic category, and circulating procalcitonin (PCT) and C-reactive protein (CRP) levels were additionally measured or recorded. Forty-five patients subsequently became septic and 44 did not. Soluble (s) E- and P-selectin levels, circulating PCT, SOFA score and diagnostic category were significantly different between the two groups. Multiple logistic regression analysis associated elevated sE- and sP-selectin levels and SOFA with an increased risk of developing sepsis, while multiple Cox regression analysis identified sE- and sP-selectin levels as the only parameters related to sepsis appearance with time [RR=1.026, 95%CI=1.008-1.045, p=0.005; RR=1.005 (by 10 units), 95%CI=1.000-1.010, p=0.034, respectively]. When trauma patients were independently analyzed, multiple Cox regression analysis revealed sE-selectin to be the only molecule associated with sepsis development with time (RR=1.041, 95%CI: 1.019-1.065; p<0.001). In conclusion, in our cohort of initially non-septic critically-ill patients, high levels of the circulating endothelial adhesion molecules E- and P-selectin, measured at ICU admission, appear to be associated with sepsis development in time.

A prospective study on endocrine function in patients with long-COVID symptoms.

OBJECTIVE: To investigate hormonal status in patients with long-COVID and explore the interrelationship between hormone levels and long-COVID symptoms. DESIGN: Prospective observational study. PARTICIPANTS: Patients who visited our long-COVID outpatients' clinic due to long-COVID symptoms from February 2021 to December 2022. MEASUREMENTS: Total triiodothyronine, free thyroxine, thyrotropin, thyroglobulin, anti-thyroperoxidase, and antithyroglobulin autoantibodies were measured for thyroid assessment. Other hormones measured were growth hormone, insulin-like growth factor 1 (IGF-1), adrenocorticotropic hormone (ACTH), serum cortisol, dehydroepiandrosterone sulfate (DHEA-S), total testosterone, plasma insulin, and C-peptide. Blood glucose and glycosylated hemoglobin were also measured. To assess adrenal reserve, an ACTH stimulation test was performed. The fatigue assessment scale (FAS) was used to evaluate fatigue severity. RESULTS: Eighty-four adult patients were included. Overall, 40.5% of the patients had at least one endocrine disorder. These included prediabetes (21.4%), low DHEA-S (21.4%), subclinical hypothyroidism (3.6%), non-specific thyroid function abnormality (7.1%), thyroid autoimmunity (7.1%), low testosterone in males (6.6%), and low IGF-1 (3.6%). All patients had normal adrenal reserve. Long-COVID-19 symptoms were present in all patients and the most commonly reported symptom was fatigue (89.3%). The FAS score was higher than normal (≥ 22) in 42.8% of patients. There were no associations between patients' symptoms and hormone levels. Diabetic patients reported confusion (p = 0.020) and hair loss (p = 0.040) more often than non-diabetics. CONCLUSIONS: The evaluation of endocrine function 3 months after a positive SARS-CoV2 test revealed only subclinical syndromes. The vast majority of patients reported mainly fatigue, among other symptoms, which were unrelated, however, to endocrine function.

A Prospective Study on Neural Biomarkers in Patients with Long-COVID Symptoms.

BACKGROUND: this prospective observational study aims to assess serum levels of glial fibrillary acidic protein (GFAP), s100b, and total Tau in long-COVID patients, exploring correlations with symptoms, cognitive decline, mental health, and quality of life. METHODS: Long-COVID patients visiting our outpatient clinic (February 2021-December 2022) were screened alongside age- and sex-matched controls. GFAP, s100b, and total Tau in serum were measured with ELISA. Cognitive function, depression, anxiety, post-traumatic stress disorder, and quality of life were evaluated using MoCA, HADS (depression and anxiety), IES-R, and SF-36, respectively. RESULTS: Sixty-five long-COVID patients and 20 controls were included. GFAP levels were significantly higher in long-COVID patients (p = 0.031), though not correlating with the presence of long-COVID symptoms. S100b and total Tau showed no significant differences between patients and controls. Nervous system-related symptoms were reported in 47% of patients. High rates of cognitive decline (65.9%), depression (32.2%), anxiety (47.5%), and post-traumatic stress disorder (44.1%) were observed. Over 80% of the study population scored below normative cutoffs for SF-36, indicating a significant impact on quality of life. CONCLUSIONS: in this long-COVID cohort with substantial psychological and cognitive symptoms, GFAP levels were elevated compared to controls, though not correlating with the presence of long-COVID symptoms.

Induced expression and functional effects of aquaporin-1 in human leukocytes in sepsis.

INTRODUCTION: Gene expression profiling was performed via DNA microarrays in leukocytes from critically ill trauma patients nonseptic upon admission to the ICU, who subsequently developed either sepsis (n = 2) or severe sepsis and acute respiratory distress syndrome (n = 3). By comparing our results with published expression profiling studies in animal models of sepsis and lung injury, we found aquaporin-1 to be differentially expressed across all studies. Our aim was to determine how the water channel aquaporin-1 is involved in regulating the immune response in critically ill patients during infection acquired in the ICU. METHODS: Following the results of the initial genetic screening study, we prospectively followed aquaporin-1 leukocyte expression patterns in patients with ICU-acquired sepsis who subsequently developed septic shock (n = 16) versus critically ill patients who were discharged without developing sepsis (n = 13). We additionally determined aquaporin-1 expression upon lipopolysaccharide (LPS) exposure and explored functional effects of aquaporin-1 induction in polymorphonuclear granulocytes (PMNs). RESULTS: Leukocyte aquaporin-1 expression was induced at the onset of sepsis (median 1.71-fold increase; interquartile range: 0.99 to 2.42, P = 0.012 from baseline) and was further increased upon septic shock (median 3.00-fold increase; interquartile range: 1.20 to 5.40, P = 0.023 from sepsis, Wilcoxon signed-rank test); no difference was observed between baseline and discharge in patients who did not develop sepsis. Stimulation of PMNs by LPS led to increased expression of aquaporin-1 in vitro, which could be abrogated by the NF-κB inhibitor EF-24. PMN hypotonic challenge resulted in a transient increase of the relative cell volume, which returned to baseline after 600 seconds, while incubation in the presence of LPS resulted in persistently increased cell volume. The latter could be abolished by blocking aquaporin-1 with mercury and restored by incubation in ß-mercaptoethanol, which abrogated the action of mercury inhibition. CONCLUSIONS: Aquaporin-1 is induced in leukocytes of patients with ICU-acquired sepsis and exhibits higher expression in septic shock. This phenomenon may be due to LPS-triggered NF-κB activation that can also lead to alterations in plasma membrane permeability.

Changes in Cortisol Secretion and Corticosteroid Receptors in COVID-19 and Non COVID-19 Critically Ill Patients with Sepsis/Septic Shock and Scope for Treatment.

Sepsis is associated with dysregulated cortisol secretion, leading to abnormal levels of cortisol in the blood. In the early stages of the condition, cortisol levels are typically elevated due to increased secretion from the adrenal glands. However, as the disease progresses, cortisol levels may decline due to impaired adrenal function, leading to relative adrenal insufficiency. The latter is thought to be caused by a combination of factors, including impaired adrenal function, decreased production of corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) by the hypothalamus and pituitary gland, and increased breakdown of cortisol. The dysregulation of cortisol secretion in sepsis is thought to contribute to the pathophysiology of the disease by impairing the body's ability to mount an appropriate inflammatory response. Given the dysregulation of cortisol secretion and corticosteroid receptors in sepsis, there has been considerable interest in the use of steroids as a treatment. However, clinical trials have yielded mixed results and corticosteroid use in sepsis remains controversial. In this review, we will discuss the changes in cortisol secretion and corticosteroid receptors in critically ill patients with sepsis/septic shock. We will also make special note of COVID-19 patients, who presented a recent challenge for ICU management, and explore the scope for corticosteroid administration in both COVID-19 and non-COVID-19 septic patients.

Prognostic Value of HIF-1α-Induced Genes in Sepsis/Septic Shock.

Hypoxia is characterized as one of the main consequences of sepsis, which is recognized as the leading cause of death in intensive care unit (ICU) patients. In this study, we aimed to examine whether the expression levels of genes regulated under hypoxia could be utilized as novel biomarkers for sepsis prognosis in ICU patients. Whole blood expression levels of hypoxia-inducible factor-1α (HIF1A), interferon-stimulated gene 15 (ISG15), hexokinase 2 (HK2), lactate dehydrogenase (LDHA), heme oxygenase-1 (HMOX1), erythropoietin (EPO), and the vascular endothelial growth factor A (VEGFA) were measured on ICU admission in 46 critically ill, initially non-septic patients. The patients were subsequently divided into two groups, based on the development of sepsis and septic shock (n = 25) or lack thereof (n = 21). HMOX1 mRNA expression was increased in patients who developed sepsis/septic shock compared to the non-septic group (p < 0.0001). The ROC curve, multivariate logistic regression, and Kaplan-Meier analysis demonstrated that HMOX1 expression could be utilized for sepsis and septic shock development probability. Overall, our results indicate that HMOX1 mRNA levels have the potential to be a valuable predictive factor for the prognosis of sepsis and septic shock in ICU patients.