AJKD Atlas of Renal Pathology: Tip Lesion Variant of Focal Segmental Glomerulosclerosis

A novel likely pathogenic CLCN5 variant in Dent's disease

BACKGROUND

The majority of cases of Dent's disease are caused by pathogenic variants in the CLCN5 gene, which encodes a voltage-gated chloride ion channel (ClC-5), resulting in proximal tubular dysfunction. We present three members of the same family and one unrelated paediatric patient with the same insertion-deletion CLCN5 variant. The identification of these patients and positive familial segregation led to the re-classification of this variant from one of unknown significance to one of likely pathogenicity.

CASE PRESENTATION

A 41 year old male presented with end stage kidney failure, proteinuria and haematuria. Whole genome sequencing identified an insertion-deletion variant in CLCN5, resulting in a missense change (c.1744_1745delinsAA p.(Ala582Lys)). His brother and nephew, who both exhibited renal impairment, haematuria, proteinuria, glycosuria and nephrocalcinosis, were found to have the same variant. In addition, genetic testing of an unrelated paediatric patient who presented with proteinuria and hypercalciuria, demonstrated the same variant.

CONCLUSIONS

The identification of this novel variant in four individuals with features of Dent's disease, has led to the re-classification of the variant to one of likely pathogenicity. As a result, our patients and any future patients with the same variant can be offered a likely diagnosis, without the need for kidney biopsy, and their family members can be offered genetic screening.

Vinpocetine reduces diclofenac-induced acute kidney injury through inhibition of oxidative stress, apoptosis, cytokine production, and NF-κB activation in mice

Acute kidney injury (AKI) represents a complex clinical condition associated with significant morbidity and mortality. Approximately, 19-33% AKI episodes in hospitalized patients are related to drug-induced nephrotoxicity. Although, considered safe, non-steroidal anti-inflammatory drugs such as diclofenac have received special attention in the past years due to the potential risk of renal damage. Vinpocetine is a nootropic drug known to have anti-inflammatory properties. In this study, we investigated the effect and mechanisms of vinpocetine in a model of diclofenac-induced AKI. We observed that diclofenac increased proteinuria and blood urea, creatinine, and oxidative stress levels 24h after its administration. In renal tissue, diclofenac also increased oxidative stress and induced morphological changes consistent with renal damage. Moreover, diclofenac induced kidney cells apoptosis, up-regulated proinflammatory cytokines, and induced the activation of NF-κB in renal tissue. On the other hand, vinpocetine reduced diclofenac-induced blood urea and creatinine. In the kidneys, vinpocetine inhibited diclofenac-induced oxidative stress, morphological changes, apoptosis, cytokine production, and NF-κB activation. To our knowledge, this is the first study demonstrating that diclofenac-induced AKI increases NF-κB activation, and that vinpocetine reduces the nephrotoxic effects of diclofenac. Therefore, vinpocetine is a promising molecule for the treatment of diclofenac-induced AKI.