A wave of deep intronic mutations in X-linked Alport syndrome.

X-linked Alport syndrome (XLAS) is an inherited kidney disease caused exclusively by pathogenic variants in the COL4A5 gene. In 10-20% of cases, DNA sequencing of COL4A5 exons or flanking regions cannot identify molecular causes. Here, our objective was to use a transcriptomic approach to identify causative events in a group of 19 patients with XLAS without identified mutation by Alport gene panel sequencing. Bulk RNAseq and/or targeted RNAseq using a capture panel of kidney genes was performed. Alternative splicing events were compared to those of 15 controls by a developed bioinformatic score. When using targeted RNAseq, COL4A5 coverage was found to be 23-fold higher than with bulk RNASeq and revealed 30 significant alternative splicing events in 17 of the 19 patients. After computational scoring, a pathogenic transcript was found in all patients. A causative variant affecting COL4A5 splicing and absent in the general population was identified in all cases. Altogether, we developed a simple and robust method for identification of aberrant transcripts due to pathogenic deep-intronic COL4A5 variants. Thus, these variants, potentially targetable by specific antisense oligonucleotide therapies, were found in a high percentage of patients with XLAS in whom pathogenic variants were missed by conventional DNA sequencing.

The spectrum of kidney biopsies in hospitalized patients with COVID-19, acute kidney injury, and/or proteinuria.

We report a multicentric retrospective case series of patients with COVID-19 who developed acute kidney injury and/or proteinuria and underwent a kidney biopsy in the Paris and its metropolitan area. Forty-seven patients (80.9% men) with COVID-19 who underwent a kidney biopsy between March 08 and May 19, 2020 were included. Median age was 63 years IQR [52-69]. Comorbidities included hypertension (66.0%), diabetes mellitus (27.7%), obesity (27.7%), history of chronic kidney (25.5%), cardiac (38.6%) and respiratory (27.3%) diseases. Initial symptoms were fever (85.1%), cough (63.8%), shortness of breath (55.3%), and diarrhea (23.4%). Almost all patients developed acute kidney injury (97.9%) and 63.8% required renal replacement therapy. Kidney biopsy showed two main histopathological patterns, including acute tubular injury in 20 (42.6%) patients, and glomerular injury consisting of collapsing glomerulopathy and focal segmental glomerulosclerosis in 17 (36.2%) patients. Two (4.3%) patients had acute vascular nephropathy, while eight (17%) had alternative diagnosis most likely unrelated to COVID-19. Acute tubular injury occurred almost invariably in the setting of severe forms of COVID-19, whereas patients with glomerular injury had various profiles of COVID-19 severity and collapsing glomerulopathy was only observed in patients harboring a combination of APOL1 risk variants. At last follow-up, 16 of the 30 patients who initially required dialysis were still on dialysis, and 9 died. The present study describes the spectrum of kidney lesions in patients with COVID-19. While acute tubular injury is correlated with COVID-19 severity, the pattern of glomerular injury is intimately associated with the expression of APOL1 risk variants.

Sofosbuvir plus ribavirin for hepatitis C virus-associated cryoglobulinaemia vasculitis: VASCUVALDIC study.

BACKGROUND: Hepatitis C virus (HCV) is the aetiological agent for most cases of cryoglobulinaemia vasculitis. Interferon-containing regimens are associated with important side effects and may exacerbate the vasculitis. OBJECTIVE: To evaluate safety and efficacy of an oral interferon-free regimen, sofosbuvir plus ribavirin, in HCV-cryoglobulinaemia vasculitis. PATIENTS AND METHODS: We enrolled 24 consecutive patients (median age of 56.5 years and 46% of women) with HCV-cryoglobulinaemia vasculitis. Sofosbuvir (400 mg/day) was associated with ribavirin (200-1400 mg/day), for 24 weeks. The primary efficacy end point was a complete clinical response of the vasculitis at the end of treatment (week 24). RESULTS: Main features of HCV-cryoglobulinaemia vasculitis included purpura and peripheral neuropathy (67%), arthralgia (58%), glomerulonephritis (21%) and skin ulcers (12%). Twenty-one patients (87.5%) were complete clinical response at week 24. Complete clinical response was achieved in six (25%) patients at week 4, four (16.6%) at week 8, seven (29.2%) at week 12, three (12.5%) at week 16 and one (4.2%) at week 20. The cryoglobulin level decreased from 0.35 (0.16-0.83) at baseline to 0.15 (0.05-0.45) g/L at week 24. The C4 serum level increased from 0.10 (0.07-0.19) to 0.17 (0.09-0.23) g/L at week 24. Seventy-four per cent of patients had a sustained virological response at week 12 post treatment. The most common side effects were fatigue, insomnia and anaemia. Two serious adverse events were observed. CONCLUSIONS: Sofosbuvir plus ribavirin combination was associated with a high rate of complete clinical response and a low rate of serious adverse events in HCV-cryoglobulinaemia vasculitis.

Kidney injuries related to ipilimumab.

Monoclonal antibodies directed against the immune checkpoint protein cytotoxic T-lymphocyte antigen-4 (CTLA-4; CD152) have been investigated in metastatic melanoma and other cancers and have shown promising results. Inhibition of CTLA-4 characteristically induces well-known side effects called "immune-related adverse events" (irAEs). IrAEs mainly include colitis, dermatitis, hepatitis, endocrinopathies; uveitis, iridocyclitis, neuropathies, and inflammatory myopathy have occasionally been reported. Kidney involvement is rare. We report 2 cases of acute granulomatous interstitial nephritis and present, based on literature review, renal disorders related to Ipilimumab therapy. Autoimmune symptoms have to be carefully checked for patients treated with CTLA-4 inhibitors. In order to reduce the risk of sequelae, early recognition of irAEs and treatment initiation are crucial.

[Doxycycline or how to create new with the old?]. / La doxycycline ou comment faire du neuf avec du vieux ?

Tetracyclines are broad-spectrum antibiotics that interfere with protein synthesis. They were first widely prescribed by dermatologists in the early 1950s in the treatment of acne. More recently, their biological actions on inflammation, proteolysis, angiogenesis, apoptosis, metal chelation, ionophoresis, and bone metabolism were studied. Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes that degrade components of the extracellular matrix (ECM). MMPs have direct or indirect effects on the vascular endothelium and the vascular relaxation/contraction system. The therapeutic effects of tetracyclines and analogues were studied in rosacea, bullous dermatoses, neutrophilic diseases, pyoderma gangrenosum, sarcoidosis, aortic aneurysms, cancer metastasis, periodontitis and autoimmune diseases autoimmune diseases such as rheumatoid arthritis and scleroderma. In addition, downregulation of MMP using doxycycline could be beneficial in reducing vascular dysfunction mediated by MMPs and progressive damage of the vascular wall. We review the nonantibiotic properties of doxycycline and its potential clinical applications.

Frequency and management of troponin I elevation in patients treated with molecular targeted therapies in phase I trials.

BACKGROUND: Cardiotoxicity of molecular targeted therapies (MTT) is poorly understood and is being investigated among patients with metastatic solid tumours. The frequency of cardiac events among patients receiving MTT has been evaluated in various ways, particularly troponin elevations. PATIENTS AND METHODS: We prospectively evaluated cardiotoxicity among patients included in Phase 1 trials receiving molecular targeted therapies (MTT) for a metastatic solid tumour. At baseline, all patients were examined before the first cycle and monitored including a clinical examination, ECG and troponin I measurement. A trans-thoracic echocardiography was performed at baseline and before each cycle. Patients were enrolled in different trials investigating : an anti-VEGF monoclonal antibody, anti-VEGFR tyrosine kinase inhibitors, and a kinesin inhibitor. RESULTS: Among the 90 patients evaluated, 10 (11%) experienced chest pain and troponin I elevation (n = 2,20%) or asymptomatic troponin I elevation (n = 8, 80%) during follow-up. All patients were re-evaluated at the time of symptoms or troponin I elevation with trans-thoracic echocardiography, cardiac magnetic resonance and coronary angiography. All except one patient, had a normal LVEF during their re-evaluation. One patient exhibited ECG changes (T wave inversion). No QTc interval prolongation was found. On cardiac magnetic resonance, no late gadolinium myocardial enhancement was observed. All coronary angiographies were normal (no occlusion, or coronary stenosis >50%). All patients received beta blockers and aspirin. All Patients were re-challenged with the study drug and no cardiotoxicity was observed during follow up. CONCLUSION: Troponin elevations are frequent among patients receiving molecular targeted therapies. Re-challenging these patients after a careful evaluation and under medical treatment seems to be possible. The mechanism underlying troponin elevations does not seem to be associated with coronary occlusion nor with toxic myocarditis.

Role of HIV-1 DNA levels as clinical marker of HIV-1-associated nephropathies.

BACKGROUND: HIV-associated nephropathy (HIVAN) is usually diagnosed in virologically uncontrolled infected patients. However, HIVAN can occur in some cases with undetectable HIV-1 RNA levels. We suggested that intracellular HIV-1 proviral DNA load can be used as a marker in this particular patient population. METHODS: Renal tissue HIV-1 proviral DNA, peripheral blood mononuclear cells (PBMCs) HIV-1 proviral DNA, plasma HIV-1 RNA and peripheral blood CD4-positive lymphocyte counts were quantified and assessed in 100 HIV-1-infected individuals (49 with undetectable HIV-1 RNA level viraemia) who underwent a kidney biopsy for renal abnormalities in a prospective study. RESULTS: A proviral DNA load was detected in patients with HIV-1-associated nephropathy with a negative plasma viral RNA load. None of the patients with a proviral DNA load of <10 copies/1.5×10(5) PBMCs had HIVAN. In renal tissue, proviral DNA load was detected in all patients with HIVAN. CONCLUSIONS: PBMC HIV-1 proviral DNA load is potentially the optimal clinical marker to exclude the diagnosis of HIVAN. On the other hand, cellular incorporation of HIV-1 within the kidney is a requisite for the development of this disorder.

Acute Kidney Injury in the Patient with Cancer.

Over the last three decades, advancements in the diagnosis, treatment, and supportive care of patients with cancer have significantly improved their overall survival. However, these advancements have also led to a higher rate of cancer-related complications. Acute kidney injury (AKI) and chronic kidney disease (CKD) are highly prevalent in patients with cancer, and they are associated with an increased risk of all-cause mortality. This bidirectional interplay between cancer and kidney, termed "the kidney-cancer connection" has become a very active area of research. This review aims to provide an overview of some of the most common causes of AKI in patients with cancer. Cancer therapy-associated AKI is beyond the scope of this review and will be discussed separately.

Rapidly progressive lupus nephritis and concomitant thrombotic microangiopathy.

Although uncommon, thrombotic microangiopathy (TMA) is one of the most serious complications in patients with systemic lupus erythematosus. A 30-year-old black woman admitted to our hospital because of fever, fatigue, 'dark' urine and rapidly progressive renal failure was found to have systemic lupus erythematous and atypical hemolytic uremic syndrome. Kidney biopsy showed WHO class IV lupus nephritis with crescents and TMA. Hemodialysis was initiated for worsening renal failure. The patient was treated with corticosteroids, monthly pulse intravenous Cyclophosphamide, plasmapheresis and Rituximab on a weekly basis for 4 weeks. The patient's blood pressure was aggressively controlled using antihypertensive agents. Despite this extensive therapy, she remained dialysis dependent although hematological parameters returned to normal values.

Pathophysiology and Pathology of Acute Kidney Injury in Patients With COVID-19.

Acute kidney injury (AKI) is common among hospitalized patients with Coronavirus Infectious Disease 2019 (COVID-19), with the occurrence of AKI ranging from 0.5% to 80%. The variability in the occurrence of AKI has been attributed to the difference in geographic locations, race/ethnicity, and severity of illness. AKI among hospitalized patients is associated with increased length of stay and in-hospital deaths. Even patients with AKI who survive to hospital discharge are at risk of developing chronic kidney disease or end-stage kidney disease. An improved knowledge of the pathophysiology of AKI in COVID-19 is crucial to mitigate and manage AKI and to improve the survival of patients who developed AKI during COVID-19. The goal of this article is to provide our current understanding of the etiology and the pathophysiology of AKI in the setting of COVID-19.

Temsirolimus-induced glomerulopathy.

A 58-year-old man with advanced renal cell carcinoma developed grade 3 proteinuria (8.5 g/24 h) without microscopic hematuria or renal insufficiency five days after temsirolimus infusion. Kidney biopsy revealed ischemic glomeruli and focal segmental glomerulosclerosis lesion. Proteinuria level decreased to 2.80 g per day two weeks after temsirolimus withdrawal. Clinicians should be aware to this complication.

A case of acute renal failure associated with diffuse infiltrative lymphocytosis syndrome.

BACKGROUND: A 58-year-old African American man with an uncontrolled HIV infection presented to hospital with nephrotic syndrome and diffuse lymphadenopathy. The patient had been taking highly active antiretroviral therapy (HAART; lamivudine, abacavir, fosamprenavir and ritonavir) for 10 years. A renal biopsy showed acute granulomatous interstitial nephritis. Despite a negative tuberculin skin test, he was treated with antituberculosis drugs for 12 months without improvement of his renal profile. Two months after antituberculosis treatment was discontinued, the patient was readmitted to hospital because of acute renal failure. Corticosteroid therapy (prednisone) was started and resulted in a marked improvement in renal function. However, 18 months after steroids were discontinued, renal function declined dramatically. Furthermore, the patient had CD8+ lymphocytosis as well as interstitial tissue infiltration by CD8+ T lymphocytes. INVESTIGATIONS: Physical examination, plasma HIV viral load, lymphocyte counts, urinalysis, tuberculin skin test, liver function tests, renal ultrasonography, human leukocyte antigen (HLA) typing, renal and minor salivary gland biopsies, ophthalmological examination, chest radiography and culture of bronchoalveolar lavage fluid. DIAGNOSIS: Acute granulomatous interstitial nephritis secondary to diffuse infiltrative lymphocytosis syndrome. MANAGEMENT: HAART and prednisone.

Angiogenesis inhibitor therapies: focus on kidney toxicity and hypertension.

Angiogenesis inhibitors that target the epidermal growth factor (EGF) receptor (EGFR) and vascular endothelial growth factor (VEGF) constitute an important addition to the therapeutic armamentarium for the treatment of patients with metastatic disease. However, because the same growth factors are expressed in the kidneys, these treatment molecules have renal side effects. EGFR is expressed mainly in tubules (mainly distal and collecting segments) and mesangial and parietal epithelial cells. EGF is involved in maintaining tubular integrity and is a potent mitogen for cultured mesangial cells. Few cases of acute renal failure have been reported related to EGFR inhibitors. VEGF and VEGF receptors are still highly expressed in the kidney. VEGF is expressed in podocytes in the glomerulus, and VEGF receptors are present on endothelial, mesangial, and peritubular capillary cells. Signaling between endothelial cells and podocytes is essential for the proper development and maintenance of the filtration function of the kidney glomerulus. The most common renal class effects of VEGF antagonists are both manageable; hypertension and proteinuria commonly regressive on drug withdrawal. There was a dose-dependent increase in risk of proteinuria and hypertension in patients with cancer who received targeted therapies. Furthermore, few patients with glomerulonephritis or thrombotic microangiopathy secondary to treatment were reported. Hypertension is believed to be nitric oxide dependent, whereas proteinuria seems to be related to downregulation of podocyte tight junction protein. This article reviews data relating to hypertension and proteinuria associated with the use of these drugs.

Sunitinib malate.

Recently, there has been a growing interest in understanding the role of receptor tyrosine kinases (RTK), such as vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR), stem cell factor receptor (KIT), and fms-like tyrosine kinase 3 (FLT3), in promoting tumor angiogenesis, tumor growth and metastasis. Sunitinib (sunitinib malate; SU11248; SUTENT; Pfizer Inc, New York, NY, USA) is a novel, orally bio-available, oxindole, multi-targeted tyrosine kinase inhibitor with high binding affinity for VEGFR and PDGFR which has shown anti-tumor and anti-angiogenic activities. This drug recently received approval from the US Food and Administration (FDA) in two indications simultaneously: advanced renal cell carcinoma (adRCC) and gastrointestinal stromal tumors (GIST), in patients who are resistant or intolerant to the treatment with imatinib. The present article reviews the recent pharmacologic and clinical data related to the use of this new promising drug in the field of oncology.

Mevalonate pathway: a review of clinical and therapeutical implications.

Mevalonate pathway is an important metabolic pathway which plays a key role in multiple cellular processes by synthesizing sterol isoprenoids, such as cholesterol, and non-sterol isoprenoids, such as dolichol, heme-A, isopentenyl tRNA and ubiquinone. While extensively studied in regard with cholesterol synthesis and its implications in cardiovascular diseases, in recent years the mevalonate pathway has become a challenging and, in the meantime, fascinating topic, when a large number of experimental and clinical studies suggested that inhibition of non-sterol isoprenoids might have valuable interest in human pathology. These molecules that are essential for cell growth and differentiation appear to be potential interesting therapeutic targets for many areas of ongoing research: oncology, autoimmune disorders, atherosclerosis, and Alzheimer disease. Also, considerable progress has been made in the past decade in understanding the pathophysiology of two auto-inflammatory disorders resulting from an inherited deficiency of mevalonate kinase, the first committed enzyme of the mevalonate pathway. Here we present a brief description of the biochemistry of the mevalonate pathway, together with a review of the current knowledge of the clinical and therapeutical implications of this fascinating and complex metabolic pathway.

Loss of podocyte dysferlin expression is associated with minimal change nephropathy.

We report a case of limb-girdle muscular dystrophy type 2B (LGMD2B) associated with minimal change disease. Immunohistochemical examination of quadriceps muscle showed a deficiency in dysferlin in sarcolemma, and dysferlin gene analysis showed 3370 G missense mutation, leading us to the diagnosis of LGMD2B. The patient also developed glomerular proteinuria. We also explored urinary protein levels in 3 other patients with dysferlinopathy and found microalbuminuria with albumin excretion of 0.14 to 0.18 g/d in 2 patients. Renal abnormalities during LGMD2B and kidney dysferlin expression have never been reported. Renal biopsy showed a lack of glomerular dysferlin expression compared with a positive immunohistochemical marking in patients with idiopathic minimal change nephropathy and healthy controls. We therefore suggest that dysferlin is present in glomeruli and may be associated with glomerular permeability.

Abnormal blood pressure circadian rhythm: a target organ damage?

Blood pressure (BP) varies according to cycles characterized by a reduction during sleep and an increase on awakening. The nighttime decrease is absent or blunted in some patients (termed "non-dippers"). Cross-sectional and prospective data have shown that non-dippers have more target organ damage than have dippers in normotensive and hypertensive subjects. We reviewed the English language literature regarding this association. A non-fortuitous association seems to exist between non-dipper status and cardiovascular risk such as stroke and cardiac events. Among diabetic patients, this phenomenon has been described to occur more often in individuals with autonomic neuropathy and with different degrees of diabetic nephropathy. In normoalbuminuric normotensive type I diabetic patients without any degree of autonomic dysfunction, according to traditional cardiovascular tests, diastolic BP (dBP) night/day ratio is associated with an increased glomerular filtration rate and an increased extracellular volume. The disruption of the circadian rhythm of sympathovagal activity in non-dipper patients was associated with higher levels in systolic BP (sBP) and dBP and with a reduced decline in sBP and dBP levels during the night. Therefore, the prognostic implications of the non-dipper status may be important since the overall 24-h blood pressure load is elevated in these individuals. These data suggest that patients in whom blood pressure decreases during the night incur less damage to their brain, kidneys, heart, and blood vessels than people with elevated nocturnal BP.

Renal tubular drug transporters.

The kidney plays an important role in the elimination of numerous hydrophilic xenobiotics, including drugs, toxins, and endogenous compounds. It has developed high-capacity transport systems to prevent urinary loss of filtered nutrients, as well as electrolytes, and simultaneously to facilitate tubular secretion of a wide range of organic ions. Transport systems for organic anions and cations are primarily involved in the secretion of drugs in renal tubules. The identification and characterization of organic anion and cation transporters have been progressing at the molecular level. To date, many members of the organic anion transporter, organic cation transporter, and organic anion-transporting polypeptide families have been found to mediate the transport of diverse organic ions. It has also been suggested that ATP-dependent primary active transporters such as MDR1/P-glycoprotein and the multidrug resistance-associated protein family function as efflux pumps of renal tubular cells for more hydrophobic molecules and anionic conjugates. Tubular reabsorption of peptide-like drugs such as beta-lactam antibiotics across the brush-border membranes appears to be mediated by two distinct H+/peptide cotransporters: PEPT1 and PEPT2. Renal disposition of drugs occurs through interaction with these diverse secretory and absorptive transporters in renal tubules. Studies of the functional characteristics, such as substrate specificity and transport mechanisms, and of the localization of drug transporters could provide information regarding the cellular network involved in renal handling of drugs. Detailed information concerning molecular and cellular aspects of drug transporters expressed in the kidney has facilitated studies of the mechanisms underlying renal disposition as well as transporter-mediated drug interactions.