Morphofunctional, Gene, Inflammation Molecules and Oxidative Stress Analysis in Kidney Tissue of COVID-19 Patients

Instituto Nacional de Enfermedades Respiratorias40 enrolled

Overview

The involvement of the kidneys in patients infected with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at the outset of the pandemic was associated with high mortality rates worldwide. This was in part due to the generation of an inflammatory process and exacerbated oxidative stress. The present study was initiated to investigate the relationship between morphofunctional changes and gene expression in the kidney tissue of deceased Mexican patients prior to the initiation of vaccination. The investigator designed a single-center, prospective, cohort study, to analyze and relate the morphofunctional changes and gene expression of inflammatory and oxidative stress molecules in the kidney tissue of men who died from severe COVID-19. A total of 40 percutaneous renal biopsies from deceased patients with severe acute respiratory syndrome coronavirus 2 infection were included in the study and divided into two a groups. One group was preserved in trizol to obtain RNA and total protein, while the remaining sample was fixed in formalin to be examined by staining with hematoxylin and eosin. The histopathological analysis was conducted by an experienced pathologist. The expression of molecules was evaluated by real-time polymerase chain reaction assay (nphs2, slc9a1, cx3cl1, havcr1, slc22a17, sod2, egf, timp2, hmox1, fabp1, and so forth). The following biomarkers were analyzed: interleukin-6, Arginase-1 (Arg-1), Dipeptidyl peptidase-4 (DPP-4), GSTT1, type I gamma-glutamyltransferase (GGT1), Occludin (OCL), CYP3A4, and Claudin-8 (CL-8). Additionally, Western blot analysis was conducted on claudin-5 (CL-5), occludin, HSP70, Nuclear factor erythroid 2-related factor-2 (NRF-2), superoxide dismutase-2 (SOD-2), nicotinamide adenine dinucleotide phosphate dehydrogenase 1 (NQO1), Gamma glutamylcysteine synthase (γ-GCL), and receptor for advanced glycation end products (RAGE). The estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, with the subjects divided into two groups based on their eGFR: \>60 or \<60 ml/min/1.73 m². The statistical analysis was conducted using the Stata program and GraphPad software, version 10.2.3.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Outcomes

Primary Outcomes

Fibrosis and sclerosis scores for identifying morphological changes in kidney tissue.

Morphological changes were evaluated by the fibrosis and sclerosis scores (mild, moderate and severe), using direct visualization of nephron compartments (glomerular and tubulointerstitial) of patients who died due to severe COVID-19.

Time frame: From the date of postmortem kidney biopsy until the date of histopathological report, in average seven days.

The estimated glomerular filtration rate for evaluating functional changes. The estimated glomerular filtration rate for evaluating functional changes.

Functional changes were calculated using the estimated glomerular filtration rate (\> 60 vs \< 60 ml/min/1.73m2) of patients who died due to severe COVID-19.

Time frame: From the date of arrival at the hospital until the date of death, in average one month.

Secondary Outcomes

Differential gene expression using polymerase chain reaction

Changes in differential gene expression in the kidney tissue of patients who died from due to severe COVID-19.

Time frame: From the date of postmortem kidney biopsy until the date of measure of differential gene expression, evaluated in 72 months.

Quantity of inflammatory molecules expressed in picograms of proteins.

Changes in the quantity of inflammatory molecules in the kidney tissue of patients who died due to severe COVID-19.

Time frame: From the date of postmortem kidney biopsy until the date of measure the inflammatory molecules expressed in the tissue, evaluated in 72 months.

Quantity of oxidative stress molecules expressed in picograms of proteins.

Changes in the quantity of oxidative stress molecules expressed in the kidney tissues of patients who died due to severe COVID-19.

Time frame: From the date of postmortem kidney biopsy to the date of measure of oxidative stress molecules expressed in the tissue report, evaluated in 72 months.