Background Recent data have shown that severe acute respiratory syndrome coronavirus 2 can infect renal proximal tubular cells via Angiotensin Converting Enzyme 2 (ACE2) . Our objective was to determine whether Fanconi syndrome is a frequent clinical feature in coronavirus disease 2019 (COVID-19) patients. Methods A retrospective cohort of 42 laboratory-confirmed COVID-19 patients without history of kidney disease hospitalized in University Hospital of Nancy was investigated. Patients were admitted to the intensive care unit (ICU) (n = 28) or the Medical department (n = 14) and were screened at least once for four markers of proximal tubulopathy. Results The mean (standard deviation) follow-up was 19.7 (±12.2) days. Of the patients, 75% (30/40) showed at least two proximal tubule abnormalities (incomplete Fanconi syndrome). The main disorders were proteinuria (88%, n = 35), renal phosphate leak defined by renal phosphate threshold/glomerular filtration rate (TmPi/GFR) <0.77 (55%, n = 22), hyperuricosuria (43%, n = 17) and normoglycaemic glycosuria (30%, n = 12). At the time of the first renal evaluation, ICU patients presented more frequent (96 versus 62%, P = 0.0095) and more severe (844 ± 343 versus 350 ± 221 mg/g, P = 0.0001) proteinuria, and a trend for an increased number of proximal tubule abnormalities (P = 0.038). During follow-up, they presented a lower nadir of serum phosphate [median (interquartile range) 0.68 (0.43–0.76) versus 0.77 (0.66–1.07) mmol/L, P = 0.044] and Acute kidney Injury (AKI) during the hospitalization (P = 0.045). Fanconi syndrome preceded severe AKI KDIGO Stages 2 and 3 in 88% (7/8) of patients. Proximal tubular abnormalities (such as proteinuria, TmPi/GFR and glycosuria in five, two and two patients, respectively) were not detected anymore in recovering patients before hospital discharge. Conclusion Incomplete Fanconi syndrome is highly frequent in COVID-19 patients and precedes AKI or disappears during the recovery phase.

Abstract Background In patients with severe coronavirus disease 2019 (COVID-19), data are scarce and conflicting regarding whether chronic use of angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) influences disease outcomes. In patients with severe COVID-19, we assessed the association between chronic ACEI/ARB use and the occurrence of kidney, lung, heart, and liver dysfunctions and the severity of the inflammatory reaction as evaluated by biomarkers kinetics, and their association with disease outcomes. Methods We performed a retrospective longitudinal cohort study on consecutive patients with newly diagnosed severe COVID-19. Independent predictors were assessed through receiver operating characteristic analysis, time-series analysis, logistic regression analysis, and multilevel modeling for repeated measures. Results On the 149 patients included in the study 30% (44/149) were treated with ACEI/ARB. ACEI/ARB use was independently associated with the following biochemical variations: phosphorus >40 mg/L (odds ratio [OR], 3.35, 95% confidence interval [CI], 1.83–6.14), creatinine >10.1 mg/L (OR, 3.22, 2.28–4.54), and urea nitrogen (UN) >0.52 g/L (OR, 2.65, 95% CI, 1.89–3.73). ACEI/ARB use was independently associated with acute kidney injury stage ≥1 (OR, 3.28, 95% CI, 2.17–4.94). The daily dose of ACEI/ARB was independently associated with altered kidney markers with an increased risk of +25 to +31% per each 10 mg increment of lisinopril-dose equivalent. In multivariable multilevel modeling, UN >0.52 g/L was independently associated with the risk of acute respiratory failure (OR, 3.54, 95% CI, 1.05–11.96). Conclusions Patients chronically treated with ACEI/ARB who have severe COVID-19 are at increased risk of acute kidney injury. In these patients, the increase in UN associated with ACEI/ARB use could predict the development of acute respiratory failure.

De novo expression in the kidney of periostin, a protein involved in odontogenesis and osteogenesis, has been suggested as a biomarker of renal disease. In this study, we investigated the mechanism(s) of induction and the role of periostin in renal disease. Using a combination of bioinformatics, reporter assay, and chromatin immunoprecipitation analyses, we found that NFkB and other proinflammatory transcription factors induce periostin expression in vitro and that binding of these factors on the periostin promoter is enriched in glomeruli during experimental GN. Mice lacking expression of periostin displayed preserved renal function and structure during GN. Furthermore, delayed administration of periostin antisense oligonucleotides in wild-type animals with GN reversed already established proteinuria, diminished tissue inflammation, and improved renal structure. Lack of periostin expression also blunted the de novo renal expression of integrin-b3 and phosphorylation of focal adhesion kinase and AKT, known mediators of integrin-b3 signaling that affect cell motility and survival, observed during GN in wild-type animals. In vitro, recombinant periostin increased the expression of integrin-b3 and the concomitant phosphorylation of focal adhesion kinase and AKT in podocytes. Notably, periostin and integrin-b3 were highly colocalized in biopsy specimens from patients with inflammatory GN. These results demonstrate that interplay between periostin and renal inflammation orchestrates inflammatory and fibrotic responses, driving podocyte damage through downstream activation of integrin-b3 signaling. Targeting periostin may be a novel therapeutic strategy for treating CKD.