Chronic Inflammation Might Protect Hemodialysis Patients From Severe COVID-19

Association between inflammatory biomarkers and postoperative acute kidney injury after cardiac surgery in patients with preoperative renal dysfunction: a retrospective pilot analysis

BACKGROUND

Acute kidney injury (AKI) represents a significant post-cardiac surgery complication, particularly prevalent among individuals with pre-existing renal dysfunction. Chronic kidney disease (CKD) is frequently accompanied by persistent, low-grade inflammation, which is known to exacerbate systemic stress responses during surgical procedures. This study hypothesizes that these inflammatory responses might influence the incidence and severity of postoperative acute kidney injury (AKI), potentially serving as a protective mechanism by preconditioning the kidney to stress.

METHODS

This retrospective study enrolled patients with preoperative renal dysfunction (eGFR between 15 and 60 ml/min/1.73 m²) who underwent cardiac surgery between January 2020 and December 2022. Preoperative inflammatory biomarkers were evaluated. The primary outcome was the incidence of postoperative AKI, as defined by the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Multivariate regression models and sensitivity analyses were conducted to ascertain the relationship between inflammatory biomarkers and AKI. Restricted cubic spines (RCS) was conducted to explore nonlinear associations between inflammatory biomarkers and AKI.

RESULTS

AKI occurred in 53.4% (392/734) of patients, accompanied by significant mortality and length of hospital stay increases in cases of AKI (P < 0.005). After full adjustment of confounders, neutrophil percentage-to-albumin ratio (OR = 0.28), systemic inflammation response index (OR = 0.70), systemic immune inflammation index (OR = 0.69), neutrophil-to-lymphocyte ratio (OR = 0.70), monocyte/high-density lipoprotein cholesterol ratio (OR = 0.53), neutrophil/high-density lipoprotein cholesterol ratio (OR = 0.43) demonstrated an inverse association with AKI. Sensitivity analyses revealed that patients in the highest quartile of these biomarkers exhibited a significantly lower prevalence of AKI compared to those in the lowest quartile (p for trend < 0.05). The RCS analysis suggested an "Inverted U-shaped" association of both LnNPAR and LnSIRI with AKI.

CONCLUSIONS

This study identified an inverse association between preoperative inflammatory biomarkers and postoperative AKI in patients with preoperative renal dysfunction. The findings implied that preoperative inflammation may play a protective role against postoperative AKI in this patient population undergoing cardiac surgery.

IL-6 and IL-17 as potential links between pre-existing hypertension and long-term COVID sequelae in patients undergoing hemodialysis: a multicenter cross-sectional study

Long COVID, characterized by persistent symptoms following acute infection, poses a significant health challenge, particularly for patients with pre-existing chronic conditions such as hypertension. We hypothesized that an increase in the production of interleukins (IL)-6 and IL-17 could serve as a potential mechanism linking pre-existing uncontrolled blood pressure (BP) to the occurrence of long-term COVID sequelae in patients undergoing hemodialysis (HD). This cross-sectional study examined serum IL-6 and IL-17 levels in 80 patients undergoing HD, considering preinfection BP, the presence of long-term COVID sequelae, and the time interval after acute COVID-19 infection, which was either 5 or 10 months. Controlled BP was defined as a 3-month average pre-dialysis BP < 140/90 mmHg and post-dialysis < 130/80 mmHg. The findings suggest that the prevalence of long-term COVID sequelae was significantly higher in patients with uncontrolled BP than in the BP-controlled group. Both IL-6 and IL-17 concentrations were also significantly higher in patients with uncontrolled BP compared with the BP-controlled group. The patients with long-term COVID sequelae had higher IL-6 and IL-17 values than the fully recovered patients at both time points, but their concentrations decreased significantly over time. Further research and prospective studies are warranted to validate these findings.

Pre-existing serum indoxyl sulfate and COVID-19 outcomes in patients undergoing hemodialysis: A retrospective cohort study

Patients undergoing hemodialysis (HD) are at increased risk of severe complications from COVID-19 due to compromised immune function and comorbidities. This retrospective study aimed to investigate the association between pre-existing serum indoxyl sulfate (IS) concentrations and COVID-19 outcomes in HD patients. Methods. Data on pre-existing IS and proinflammatory cytokines, such as interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor-alpha (TNF-α) were extracted from an existing patient database. The patients were followed up for 1.5 years and compared according to median serum IS concentration: low-IS (< 22.2 μg/mL) and high-IS (≥22.2 μg/mL) groups. The primary outcomes focused on assessing the risk and severity of COVID-19 infection. Results. A total of 56 patients aged 62 (56-67) years with a dialysis vintage of 37.5 (30-168) months were included in the analysis. Serum levels of IS were significantly correlated with Kt/V values (p = 0.043), arterial hypertension (p = 0.001), IL-6 (p = 0.023), MCP-1 (p = 0.023), and TNF-α (p = 0.033) concentrations. Elevated serum IS levels were significantly associated with an increased risk of COVID-19 infection (p < 0.0001) and a higher likelihood of hospitalization (p = 0.03). Patients with higher IS levels exhibited more severe lung involvement (p < 0.0001) and a greater need for respiratory support (p = 0.004). A serum IS concentration of 21.5 μg/mL was the optimal threshold for predicting COVID-19 infection in HD patients (sensitivity of 83.4% and specificity of 92.3%, p < 0.0001). Conclusion: Our study highlights the detrimental impact of serum IS on COVID-19 infection and its clinical outcomes in patients undergoing HD. Further research is warranted to elucidate the underlying mechanisms and explore potential therapeutic strategies targeting IS in this population.

Growth Differentiation Factor 15 (GDF-15) Levels Associate with Lower Survival in Chronic Kidney Disease Patients with COVID-19

A cytokine storm drives the pathogenesis of severe COVID-19 infection and several biomarkers have been linked to mortality. Chronic kidney disease (CKD) emerged as a risk factor for severe COVID-19. We investigated the association between selected biomarkers and mortality in 77 patients hospitalized for COVID-19, and whether they differ in patients with eGFR higher and lower than 45 mL/min. The association between patients’ characteristics, plasma biomarkers and mortality was conducted by univariate logistic regression models and independent predictors of mortality were then used to create a multivariate prediction model through Cox regression. Patients with lower eGFR had a significant increase of GDF-15, CD-25 and RAGE, with higher plasma levels in non-survivors and in patients who needed ventilation. At univariate analysis, low and mid-low GDF-15 quartiles (<4.45 ng/mL) were associated with lower mortality risk, while mid-high and high quartiles (>4.45 ng/mL) were associated with higher mortality risk. Independent association between GDF-15 quartiles and mortality risk was confirmed in the Cox model and adjusted for eGFR, age, fever and dyspnea (HR 2.28, CI 1.53−3.39, p < 0.0001). The strength of the association between GDF-15 quartiles and mortality risk increased in patients with lower compared to higher eGFR (HR 2.53, CI 1.34−4.79 versus HR 1.99, CI 1.17−3.39). Our findings may suggest a further investigation of the effect of GDF-15 signaling pathway inhibition in CKD.

Characterization of regulatory T cells in SARS-CoV-2 infected hemodialysis patients: relation to clinical and radiological severity

BACKGROUND

Disordered Treg counts and function have been observed in patients with SARS-Cov-2 and are thought to contribute to disease severity. In hemodialysis patients, scarce data are available on the Treg response to SARS-CoV-2 or its relation to the clinical presentation.

METHODS

A cross-sectional study included one hundred patients divided into three groups, thirty SARS-CoV-2-infected hemodialysis patients (COV-HD), and thirty confirmed SARSCoV-2 infected patients (COV), and forty non-infected hemodialysis patients (HD). Flow cytometric analysis of CD4, CD25, FoxP3, and CD39+ Tregs was done for all patients and tested for correlation to in-hospital mortality, clinical, radiological severity indices.

RESULTS

COV-HD and COV patients had significantly lower Treg cell count than HD patients (Median value of 0.016 cell/ μl vs 0.28 cell/ μl, respectively- P: 0.001). COV-HD patients had higher CD39+ Tregs (median value of 0.006 cell/ μl vs 0.002 cell/ μl, respectively- P: 0.04). COV-HD patients had significantly lower hospital stay (median value of 3 vs 13 days, P:0.001), ICU admission rates (26.5% vs 46.7%, P:0.005) and in-hospital mortality (20.7% versus 43.3%, P:0.003) than COV patients. Treg and CD39 expressing Treg counts were not correlated to severity indices in both groups. A high neutrophil to lymphocyte ratio is strongly correlated to disease severity in COV-HD patients.

CONCLUSIONS

This study provides evidence of T-cell, particularly T-regulatory cell decline in SARS-CoV-2 and suggests that hemodialysis per se does not distinctively impact the T-cell response. COV-HD patients exhibited a higher CD39+ Treg count and a better clinical profile, however, larger studies are needed to extrapolate on these findings.

Alterations in the Kynurenine-Tryptophan Pathway and Lipid Dysregulation Are Preserved Features of COVID-19 in Hemodialysis

Coronavirus disease 2019 (COVID-19)-induced metabolic alterations have been proposed as a source for prognostic biomarkers and may harbor potential for therapeutic exploitation. However, the metabolic impact of COVID-19 in hemodialysis (HD), a setting of profound a priori alterations, remains unstudied. To evaluate potential COVID-19 biomarkers in end-stage kidney disease (CKD G5), we analyzed the plasma metabolites in different COVID-19 stages in patients with or without HD. We recruited 18 and 9 asymptomatic and mild, 11 and 11 moderate, 2 and 13 severely affected, and 10 and 6 uninfected HD and non-HD patients, respectively. Plasma samples were taken at the time of diagnosis and/or upon admission to the hospital and analyzed by targeted metabolomics and cytokine/chemokine profiling. Targeted metabolomics confirmed stage-dependent alterations of the metabolome in non-HD patients with COVID-19, which were less pronounced in HD patients. Elevated kynurenine levels and lipid dysregulation, shown by an increase in circulating free fatty acids and a decrease in lysophospholipids, could distinguish patients with moderate COVID-19 from non-infected individuals in both groups. Kynurenine and lipid alterations were also associated with ICAM-1 and IL-15 levels in HD and non-HD patients. Our findings support the kynurenine pathway and plasma lipids as universal biomarkers of moderate and severe COVID-19 independent of kidney function.

Validation of a simple risk stratification tool for COVID-19 mortality

Risk prediction is an essential part of clinical care, in order to allocate resources and provide care appropriately. During the COVID-19 pandemic risk prediction became a matter of political and public debate as a major clinical need to guide medical and organizational decisions. We previously presented a simplified risk stratification score based on a nomogram developed in Wuhan, China in the early phase of the pandemic. Here we aimed to validate this simplified risk stratification score in a larger patient cohort from one city in Austria. Age, oxygen saturation, C-reactive protein levels and creatinine levels were used to estimate the in-hospital mortality risk for COVID-19 patients in a point based score: 1 point per age decade, 4 points for oxygen saturation <92%, 8 points for CRP > 10 mg/l and 4 points for creatinine > 84 μmol/l. Between June 2020 and March 2021, during the “second wave” of the pandemic, 1,472 patients with SARS-CoV-2 infection were admitted to two hospitals in Graz, Austria. In 961 patients the necessary dataset to calculate the simplified risk stratification score was available. In this cohort, as in the cohort that was used to develop the score, a score above 22 was associated with a significantly higher mortality (p < 0.001). Cox regression confirmed that an increase of one point in the risk stratification score increases the 28-day-mortality risk approximately 1.2-fold. Patients who were categorized as high risk (≥22 points) showed a 3–4 fold increased mortality risk. Our simplified risk stratification score performed well in a separate, larger validation cohort. We therefore propose that our risk stratification score, that contains only two routine laboratory parameter, age and oxygen saturation as variables can be a useful and easy to implement tool for COVID-19 risk stratification and beyond. The clinical usefulness of a risk prediction/stratification tool needs to be assessed prospectively (https://www.cbmed.at/covid-19-risk-calculator/).

The efficacy of combined therapy of qingfeiPaidu capsule and lianhuaqingwen capsule nursing interventions for hospitalized patients with COVID-19: A retrospective study of medical records

Coronavirus disease-19 (COVID-19) caused a global pandemic burden, affecting hundreds of thousands of individuals, having life-threatening outcomes. Traditional Chinese Medicine plays a crucial role in the treatment of patients with COVID-19. The purpose of this study was to investigate the efficacy of combined therapy of qingfeiPaidu (QFPD) capsule and lianhuaqingwen (LHQW) capsule nursing interventions in the treatment of patients with COVID-19. A total of 318 patients with COVID-19 were enrolled and randomly received QFPD (n = 106), LHQW (n = 106), and QFPD-LHQW (n = 106). The clinical characteristics of COVID-19, the total lung severity scores, and blood laboratory indices were recorded in each patient in each group before treatment and at the end of treatment. The outcomes demonstrated that QFPD-LHQW group shortened the length of hospitalization, decreased C-reactive protein, creatine kinase, creatine kinase-myocardial band, lactate dehydrogenase, and blood urea nitrogen levels, and improved clinical symptoms, pulmonary inflammation, and prognosis. At the end of treatment, inflammation, immune function, circulating white blood cells, total lymphocyte count, and glutamic-oxaloacetic transaminase levels improved dramatically in 3 groups compared with baseline. All patients met the discharge criteria after 30-day treatment in 3 groups. Combined therapy of QFPD and LHQW demonstrated significant anti-inflammatory effects compared with those of only QFPD or LHQW in patients with mild and moderate COVID-19. The combined therapies may alleviate clinical symptoms of COVID-19 patients by improving inflammation and immune function.