Alkali therapy protects renal function, suppresses inflammation, and improves cellular metabolism in kidney disease.

Chronic kidney disease (CKD) affects approximately 10-13% of the population worldwide and halting its progression is a major clinical challenge. Metabolic acidosis is both a consequence and a possible driver of CKD progression. Alkali therapy counteracts these effects in CKD patients, but underlying mechanisms remain incompletely understood. Here we show that bicarbonate supplementation protected renal function in a murine CKD model induced by an oxalate-rich diet. Alkali therapy had no effect on the aldosterone-endothelin axis but promoted levels of the anti-aging protein klotho; moreover, it suppressed adhesion molecules required for immune cell invasion along with reducing T-helper cell and inflammatory monocyte invasion. Comparing transcriptomes from the murine crystallopathy model and from human biopsies of kidney transplant recipients (KTRs) suffering from acidosis with or without alkali therapy unveils parallel transcriptome responses mainly associated with lipid metabolism and oxidoreductase activity. Our data reveal novel pathways associated with acidosis in kidney disease and sensitive to alkali therapy and identifies potential targets through which alkali therapy may act on CKD and that may be amenable for more targeted therapies.

Long-term renal outcomes of APRT deficiency presenting in childhood.

BACKGROUND: Adenine phosphoribosyltransferase (APRT) deficiency is a hereditary purine metabolism disorder that causes kidney stones and chronic kidney disease (CKD). The purpose of this study was to examine the course of APRT deficiency in patients who presented in childhood. METHODS: The disease course of 21 (35%) patients in the APRT Deficiency Registry of the Rare Kidney Stone Consortium, who presented with manifestations of APRT deficiency and/or were diagnosed with the disorder before the age of 18 years, was studied. The effect of pharmacotherapy on renal manifestations and outcomes was thoroughly assessed. RESULTS: Fourteen children were placed on allopurinol, 100 (25-200) mg/day, at the age of 2.6 (0.6-16.5) years. Six of these patients had experienced kidney stone events and three had developed acute kidney injury (AKI) prior to allopurinol treatment. During 18.9 (1.7-31.5) years of pharmacotherapy, stones occurred in two patients and AKI in three. Six adult patients started allopurinol treatment, 200 (100-300) mg/day, at age 29.8 (20.5-42.4) years. Five of these patients had experienced 28 stone episodes and AKI had occurred in two. Stone recurrence occurred in four patients and AKI in two during 11.2 (4.2-19.6) years of allopurinol therapy. Lack of adherence and insufficient dosing contributed to stone recurrence and AKI during pharmacotherapy. At latest follow-up, estimated glomerular filtration rate (eGFR) was 114 (70-163) and 62 (10-103) mL/min/1.73 m2 in those who initiated treatment as children and adults, respectively. All three patients with CKD stages 3-5 at the last follow-up were adults when pharmacotherapy was initiated. CONCLUSION: Timely diagnosis and treatment of APRT deficiency decreases renal complications and preserves kidney function.

The macrophage phenotype and inflammasome component NLRP3 contributes to nephrocalcinosis-related chronic kidney disease independent from IL-1-mediated tissue injury.

Primary/secondary hyperoxalurias involve nephrocalcinosis-related chronic kidney disease (CKD) leading to end-stage kidney disease. Mechanistically, intrarenal calcium oxalate crystal deposition is thought to elicit inflammation, tubular injury and atrophy, involving the NLRP3 inflammasome. Here, we found that mice deficient in NLRP3 and ASC adaptor protein failed to develop nephrocalcinosis, compromising conclusions on nephrocalcinosis-related CKD. In contrast, hyperoxaluric wild-type mice developed profound nephrocalcinosis. NLRP3 inhibition using the ß-hydroxybutyrate precursor 1,3-butanediol protected such mice from nephrocalcinosis-related CKD. Interestingly, the IL-1 inhibitor anakinra had no such effect, suggesting IL-1-independent functions of NLRP3. NLRP3 inhibition using 1,3-butanediol treatment induced a shift of infiltrating renal macrophages from pro-inflammatory (CD45+F4/80+CD11b+CX3CR1+CD206-) and pro-fibrotic (CD45+F4/80+CD11b+CX3CR1+CD206+TGFß+) to an anti-inflammatory (CD45+F4/80+CD11b+CD206+TGFß-) phenotype, and prevented renal fibrosis. Finally, in vitro studies with primary murine fibroblasts confirmed the non-redundant role of NLRP3 in the TGF-ß signaling pathway for fibroblast activation and proliferation independent of the NLRP3 inflammasome complex formation. Thus, nephrocalcinosis-related CKD involves NLRP3 but not necessarily via intrarenal IL-1 release but rather via other biological functions including TGFR signaling and macrophage polarization. Hence, NLRP3 may be a promising therapeutic target in hyperoxaluria and nephrocalcinosis.

Dramatic Increase of Amoxicillin-Induced Crystal Nephropathy Found in a Cohort Study of French Pharmacovigilance Centers.

An increase in amoxicillin-induced crystal nephropathy (AICN) incidence has been recently suggested. The aims of this study were to investigate the trend of AICN incidence through Paris' regional centers of pharmacovigilance (Paris RCPVs) and better describe this rare adverse drug reaction. Forty-five AICN cases were identified between 1985 and 2016. All cases, except one, were reported since 2010. Amoxicillin (AMX) was administered intravenously (65 [interquartile range {IQR}, 43 to 110] mg/kg of body weight/day) in all patients, either for treating infection (n = 15) or as surgical prophylaxis (n = 30). Delay between AMX administration and AICN onset was 1 (IQR, 1 to 3) day; 30, 4, and 11 patients developed KDIGO stage 1, 2, and 3 acute kidney injury, respectively. Delay between AICN onset and kidney function recovery was 4 (IQR, 2 to 6) days. Precipitating factors were identified in only one-third of cases. Twelve patients required intensive care unit admission, and 8 needed renal replacement therapy. Neither chronic kidney disease nor death was observed. We confirmed the recent and dramatic increase of AICN in the Paris RCPVs since 2010. The absence of precipitating factors in the majority of cases and the onset of AICN in apparent routine indications, such as surgical prophylaxis, are alarming and justify a high vigilance from all AMX prescribers.

Tumor necrosis factor superfamily ligand mRNA expression profiles differ between humans and mice during homeostasis and between various murine kidney injuries.

BACKGROUND: Several tumour necrosis factor (TNF) based therapeutics have already been approved for human use and several others are emerging. Therefore, we determined the mRNA expression levels of the TNF superfamily ligands (TNFSF) - e.g. TNF-α, lymphotoxin (LT)-α, LT-ß, Fas-L (CD95-L), TNF-related apoptosis-inducing ligand (TRAIL), TNF-related weak inducer of apoptosis (TWEAK), 4-1BBL, OX40-L (CD252) and amyloid precursor protein (APP) in healthy human and mouse solid organs. METHODS: We used quantitative real time-PCR to analyse mRNA expression levels of TNFSF ligands. Murine models of acute ischemic renal injury, chronic oxalate nephropathy, and immune complex glomerulonephritis were used. Renal injury was assessed by PAS staining, and infiltrating immune cells were analysed by immunohistochemistry. Data was analysed using non-parametric ANOVA (non-parametric; Kruskal-Wallis test). RESULTS: We observed significant differences in the mRNA expression levels of TNFSF ligands in human and mouse solid organs. Furthermore, we determined their mRNA expressions during acute and chronic kidney injuries in mice. Our data demonstrate that the mRNA expression levels of TNFSF vary depending on the type of tissue injury - for example, acute ischemic renal injury, chronic crystalline nephropathy, and immune complex glomerulonephritis. In addition, we observed that mRNA expressions of TNFSF ligands are differentially regulated during the course of a transient ischemic renal injury (IRI) and chronic kidney modelling. We observed that TNF-α, LT-ß, and 4-1BBL were significantly upregulated during the progression of IRI and crystal-induced chronic kidney disease (CKD), whereas only 4-1BBL and TNF-α were significantly upregulated and LT-ß was significantly downregulated during the progression of immune complex glomerulonephritis. The mRNA expression of Fas-L was higher during IRI whereas it decreased in a time dependent manner during the progression of crystal-induced CKD. CONCLUSION: We conclude that the injury- and species-specific differences of TNFSF ligands must be considered in order to avoid the misinterpretation and wrong conclusions during data extrapolation between species.

Kidney Disease in Adenine Phosphoribosyltransferase Deficiency.

BACKGROUND: Adenine phosphoribosyltransferase (APRT) deficiency is a purine metabolism disorder causing kidney stones and chronic kidney disease (CKD). The course of nephrolithiasis and CKD has not been well characterized. The objective of this study was to examine long-term kidney outcomes in patients with APRT deficiency. STUDY DESIGN: An observational cohort study. SETTING & PARTICIPANTS: All patients enrolled in the APRT Deficiency Registry of the Rare Kidney Stone Consortium. OUTCOMES: Kidney stones, acute kidney injury (AKI), stage of CKD, end-stage renal disease, estimated glomerular filtration rate (eGFR), and changes in eGFR. MEASUREMENTS: Serum creatinine and eGFR calculated using creatinine-based equations. RESULTS: Of 53 patients, 30 (57%) were females and median age at diagnosis was 37.0 (range, 0.6-67.9) years. Median duration of follow-up was 10.3 (range, 0.0-31.5) years. At diagnosis, kidney stones had developed in 29 (55%) patients and 20 (38%) had CKD stages 3 to 5, including 11 (21%) patients with stage 5. At latest follow-up, 33 (62%) patients had experienced kidney stones; 18 (34%), AKI; and 22 (42%), CKD stages 3 to 5. Of 14 (26%) patients with stage 5 CKD, 12 had initiated renal replacement therapy. Kidney stones recurred in 18 of 33 (55%) patients. The median eGFR slope was -0.38 (range, -21.99 to 1.42) mL/min/1.73m(2) per year in patients receiving treatment with an xanthine dehydrogenase inhibitor and -5.74 (range, -75.8 to -0.10) mL/min/1.73m(2) per year in those not treated prior to the development of stage 5 CKD (P=0.001). LIMITATIONS: Use of observational registry data. CONCLUSIONS: Progressive CKD and AKI episodes are major features of APRT deficiency, whereas nephrolithiasis is the most common presentation. Advanced CKD without a history of kidney stones is more prevalent than previously reported. Our data suggest that timely therapy may retard CKD progression.

A case of acute kidney injury from crystal nephropathy secondary to pomalidomide and levofloxacin use.

Pomalidomide is an analog of thalidomide with immunomodulatory, anti-angiogenic, and anti-neoplastic activity indicated for the treatment of multiple myeloma refractory to at least two prior therapies. The incidence for renal failure was <5% in a single phase II study of pomalidomide and dexamethasone in patients with multiple myeloma that failed both lenalidomide and bortezomib therapy. We report a case suggesting crystal nephropathy as the mechanism for acute kidney injury in pomalidomide and fluoroquinolone use.

Canonical and non-canonical effects of the NLRP3 inflammasome in kidney inflammation and fibrosis.

NLRP-3 inflammasome is one of several intracellular danger recognition platforms that integrates infectious or non-infectious types of danger into the expression of pro-inflammatory cytokines to set-up inflammation for danger control. NLRP3 activation induces three types of caspase-1-mediated responses: secretion of IL-1beta, secretion of IL-18 and a programmed form of cell death, referred to as pyroptosis. Similar to the well-documented impact of Toll-like receptor-driven danger signalling in kidney disease, evolving data now suggest a similar involvement of the NLRP3 inflammasome in renal inflammation. Here, we discuss the accumulating data on NLRP3 in the kidney: its IL-1beta and IL-18-dependent 'canonical' effects and the current evidence for its 'non-canonical' effects, e.g. in tumor growth factor (TGF)-beta signalling, epithelial-mesenchymal transition and fibrosis. Research in this area will certainly uncover yet unknown aspects of danger signalling in the kidney and how it drives renal inflammation and immunopathology.

Evidence of tosufloxacin deposition in the kidneys of a patient presenting with crystal nephropathy.

Tosufloxacin tosilate is classified as a new quinolone antibacterial agent, which has been reported to cause crystal nephropathy. However, the origin of these crystal deposits has not yet been elucidated. We encountered a case of renal failure that progressed slowly owing to crystal-forming interstitial nephritis after long-term exposure to tosufloxacin. Mass spectrometry of the renal specimens revealed that tosufloxacin was deposited in the kidneys. The patient's renal function improved slowly with the withdrawal of tosufloxacin and steroid therapy. This is the first case to demonstrate the presence of crystal deposits consisting of tosufloxacin.

First analytical confirmation of drug-induced crystal nephropathy in felines caused by GS-441524, the active metabolite of Remdesivir.

GS-441524 is an adenosine nucleoside antiviral demonstrating significant efficacy in the treatment of feline infectious peritonitis (FIP), an otherwise fatal illness, resulting from infection with feline coronavirus. However, following the emergence of COVID-19, veterinary development was halted, and Gilead pursued clinical development of a GS-441524 pro-drug, resulting in the approval of Remdesivir under an FDA emergency use authorization. Despite lack of regulatory approval, GS-441524 is available without a prescription through various unlicensed online distributors and is commonly purchased by pet owners for the treatment of FIP. Herein, we report data obtained from the analytical characterization of two feline renal calculi, demonstrating the propensity for GS-441524 to cause renal toxicity through drug-induced crystal nephropathy in vivo. As definitive diagnosis of drug-induced crystal nephropathy requires confirmation of the lithogenic material to accurately attribute a mechanism of toxicity, renal stone composition and crystalline matrix were characterized using ultra-performance liquid chromatography photodiode array detection (UPLC-PDA), ultra-performance liquid chromatography mass spectrometry (LCMS), nuclear magnetic resonance (NMR) spectroscopy, X-ray powder diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). This work serves to provide the first analytical confirmation of GS-441524-induced crystal nephropathy in an effort to support toxicologic identification of adverse renal effects caused by administration of GS-441524 or any pro-drug thereof.

Management of de novo nephrolithiasis after kidney transplantation: a comprehensive review from the European Renal Association CKD-MBD working group.

The lifetime incidence of kidney stones is 6%-12% in the general population. Nephrolithiasis is a known cause of acute and chronic kidney injury, mediated via obstructive uropathy or crystal-induced nephropathy, and several modifiable and non-modifiable genetic and lifestyle causes have been described. Evidence for epidemiology and management of nephrolithiasis after kidney transplantation is limited by a low number of publications, small study sizes and short observational periods. Denervation of the kidney and ureter graft greatly reduces symptomatology of kidney stones in transplant recipients, which may contribute to a considerable underdiagnosis. Thus, reported prevalence rates of 1%-2% after kidney transplantation and the lack of adverse effects on allograft function and survival should be interpreted with caution. In this narrative review we summarize current state-of-the-art knowledge regarding epidemiology, clinical presentation, diagnosis, prevention and therapy of nephrolithiasis after kidney transplantation, including management of asymptomatic stone disease in kidney donors. Our aim is to strengthen clinical nephrologists who treat kidney transplant recipients in informed decision-making regarding management of kidney stones. Available evidence, supporting both surgical and medical treatment and prevention of kidney stones, is presented and critically discussed. The specific anatomy of the transplanted kidney and urinary tract requires deviation from established interventional approaches for nephrolithiasis in native kidneys. Also, pharmacological and lifestyle changes may need adaptation to the specific situation of kidney transplant recipients. Finally, we point out current knowledge gaps and the need for additional evidence from future studies.

Mrc1+ macrophage-derived IGF1 mitigates crystal nephropathy by promoting renal tubule cell proliferation via the AKT/Rb signaling pathway.

Rationale: The present understanding of the cellular characteristics and communications in crystal nephropathy is limited. Here, molecular and cellular studies combined with single-cell RNA sequencing (scRNA-seq) were performed to investigate the changes in cell components and their interactions in glyoxylate-induced crystallized kidneys to provide promising treatments for crystal nephropathy. Methods: The transcriptomes of single cells from mouse kidneys treated with glyoxylate for 0, 1, 4, or 7 days were analyzed via 10× Genomics, and the single cells were clustered and characterized by the Seurat pipeline. The potential cellular interactions between specific cell types were explored by CellChat. Molecular and cellular findings related to macrophage-to-epithelium crosstalk were validated in sodium oxalate (NaOx)-induced renal tubular epithelial cell injury in vitro and in glyoxylate-induced crystal nephropathy in vivo. Results: Our established scRNA atlas of glyoxylate-induced crystalline nephropathy contained 15 cell populations with more than 40000 single cells, including relatively stable tubular cells of different segments, proliferating and injured proximal tubular cells, T cells, B cells, and myeloid and mesenchymal cells. In this study, we found that Mrc1+ macrophages, as a subtype of myeloid cells, increased in both the number and percentage within the myeloid population as crystal-induced injury progresses, and distinctly express IGF1, which induces the activation of a signal pathway to dominate a significant information flow towards injured and proliferating tubule cells. IGF1 promoted the repair of damaged tubular epithelial cells induced by NaOx in vitro, as well as the repair of damaged tubular epithelial cells and the recovery of disease outcomes in glyoxylate-induced nephrolithic mice in vivo. Conclusion: After constructing a cellular atlas of glyoxylate-induced crystal nephropathy, we found that IGF1 derived from Mrc1+ macrophages attenuated crystal nephropathy through promoting renal tubule cell proliferation via the AKT/Rb signaling pathway. These findings could lead to the identification of potential therapeutic targets for the treatment of crystal nephropathy.

A case of 2,8-DHA crystalline nephropathy caused by adenine phosphoribosyltransferase deficiency: diagnosis and treatment.

Adenine phosphoribosyltransferase (APRT) deficiency is a rare autosomal recessive disorder that leads to the accumulation of poorly soluble 2,8-dihydroxyadenine (DHA) in the kidneys, resulting in a variety of renal presentations including nephrolithiasis, acute kidney injury, and chronic kidney disease (CKD) caused by crystal nephropathy. Here, we report a case of a 43-year-old man with 2,8-DHA crystalline nephropathy caused by APRT deficiency strongly suspected by renal biopsy results and definitively diagnosed by a urine gas chromatography-mass spectrometry (GC/MS)-based plasma metabolomic assessment. This case represents the importance of awareness and recognition of the signs and symptoms of this rare condition and its progression to CKD, which can be prevented by the early administration of xanthine oxidoreductase inhibitors.

Crystal nephropathy and amoxicillin: insights from international spontaneous reporting systems.

BACKGROUND: A substantial increase in amoxicillin-induced crystal nephropathy was recently reported in France. Our study aims to further characterize this safety issue from a worldwide perspective. METHODS: We queried both the FDA Adverse Event Reporting System (FAERS) and the Eudravigilance databases, and performed disproportionality analysis, selecting only adverse events (AEs) related to crystal nephropathy where amoxicillin or amoxicillin/clavulanic acid were reported as suspect. In FAERS, the reporting odds ratios were calculated and deemed significant by the lower limit of the 95% confidence interval (LL95%CI) > 1, selecting all other drugs/events recorded in FAERS as comparator. Deduplication followed by case-by-case assessment and comparison between French and non-French cases were also performed in both databases. RESULTS: Overall, 57,754 and 84,764 AE reports with amoxicillin or amoxicillin/clavulanic acid were recorded in FAERS and Eudravigilance, respectively, with France accounting for 18.7% and 22.0% of cases. Specific AEs of interest were retrieved in 144 and 239 cases, respectively. Increased reporting was found in FAERS for crystalluria (N = 99; LL95%CI 53.18), crystal nephropathy (24; 27.01), medication crystal in urine present (9; 92.00), crystal urine (8; 11.90), and crystal urine present (4; 1.57). In FAERS and Eudravigilance databases, reports were classified as serious in 98.8% and 91.2% of cases, respectively. Acute kidney injury (AKI) was found in 81.2% and 71.1% of patients. Amoxicillin was mainly given intravenously, and a dose ≥ 12 g/day was administered in 50.0% and 19.7% of cases in the FAERS and Eudravigilance databases, respectively. CONCLUSION: Although causal association cannot be firmly inferred, a consistent signal of crystal nephropathy with amoxicillin emerged, especially in France. Clinicians should monitor patients for possible early AKI onset, especially when dealing with intravenous administration of daily doses > 12 g.

Acute Kidney Injury following Exposure to Formaldehyde-Free Hair-Straightening Products.

Formaldehyde-free hair-straightening products are hair-smoothening solutions widely used by professional beauty salons. Formaldehyde-free hair straighteners do not technically contain formaldehyde; however, they contain other chemicals such as glyoxyloyl carbocysteine which releases formaldehyde upon contact with heat. Moreover, its by-product glyoxylate may convert to oxalate; both compounds have potential nephrotoxic effect. Here, we report a case of a 41-year-old woman who presented to the emergency room with weakness, nausea, vomiting, and stage 3 acute kidney injury (AKI) according to Kidney Disease: Improving Global Outcomes (KDIGO) acute kidney injury staging shortly after exposure to formaldehyde-free hair-straightening product; other causes of AKI were excluded such as preceding acute illness, drug history, or other nephrotoxic agent exposure. On physical examination, the patient was pale, and her vital signs were normal. The urine microscopy and serologic workup were not indicative. Kidney core biopsy revealed interstitial edema, acute interstitial nephritis, and oxalate crystal nephropathy. Kidney function completely recovered after a short course of steroid therapy. In this case, AKI was a complication caused by exposure to hair-straightening products branded as formaldehyde free but actually containing other chemical products which release formaldehyde and other toxic chemicals when heated during the straightening procedure and may cause systemic toxicity, particularly kidney injury. Different cosmetic products are widely in use, but not all are under tight regulation, and therefore, it is important to raise the awareness among both medical teams and consumers of possible adverse health effects of different cosmetic products.

In Situ Identification of Unknown Crystals in Acute Kidney Injury Using Raman Spectroscopy.

Raman spectroscopy is a well-established and powerful tool for in situ biomolecular evaluation. Type 2 crystal nephropathies are characterized by the deposition of crystalline materials in the tubular lumen, resulting in rapid onset of acute kidney injury without specific symptoms. Timely crystal identification is essential for its diagnosis, mechanism exploration and therapy, but remains challenging. This study aims to develop a Raman spectroscopy-based method to assist pathological diagnosis of type 2 crystal nephropathies. Unknown crystals in renal tissue slides from a victim suffered extensive burn injury were detected by Raman spectroscopy, and the inclusion of crystals was determined by comparing Raman data with established database. Multiple crystals were scanned to verify the reproducibility of crystal in situ. Raman data of 20 random crystals were obtained, and the distribution and uniformity of substances in crystals were investigated by Raman imaging. A mouse model was established to mimic the crystal nephropathy to verify the availability of Raman spectroscopy in frozen biopsy. All crystals on the human slides were identified to be calcium oxalate dihydrate, and the distribution and content of calcium oxalate dihydrate on a single crystal were uneven. Raman spectroscopy was further validated to be available in identification of calcium oxalate dihydrate crystals in the biopsy specimens. Here, a Raman spectroscopy-based method for in situ identification of unknown crystals in both paraffin-embedded tissues and biopsy specimens was established, providing an effective and promising method to analyze unknown crystals in tissues and assist the precise pathological diagnosis in both clinical and forensic medicine.

Recurrent DHA nephropathy in renal allograft-revisiting clinicopathological aspects of a rare entity.

BACKGROUND: Adenine phosphoribosyltransferase (APRT) enzyme deficiency is a rare autosomal recessive disorder of purine metabolism affecting mainly the kidneys. It can present at any age with varying degrees of acute and chronic renal damage. Though xanthine dehydrogenase inhibitors offer effective control over the disease process, delay in diagnosis and treatment often lead to compromised function of native and even graft kidneys. METHODS: We have done a retrospective search of records of renal biopsies reported at our center during the 5-year period from 2014 to 2018 to identify biopsies with 2,8-dihydroxyadenine crystal deposits. The demographic, clinical, and histopathological findings in these cases were studied and reviewed in the light of available literature. RESULTS: Of 9059 renal biopsies received during the study period, 3 cases had the rare 2,8- dihydroxyadenine (DHA) crystals. All of them were diagnosed for the first time on allograft biopsies. CONCLUSION: A high index of clinical suspicion together with the characteristic microscopic appearance of crystals on renal biopsy and urine microscopy can clinch the diagnosis of this rare disease. Hence, improving awareness about this entity among clinicians and pathologists is extremely important.

A Rare Case of APRT Deficiency with End-stage Renal Failure and Successful Renal Transplant.

Renal calculus disease is a common cause of renal injury. However, crystal nephropathy (uric acid, oxalate, and dihydroxyadenine) can present as chronic kidney disease without any evidence of renal stones. If left undiagnosed, there is a potential chance of recurrence in the allograft leading to graft failure after transplantation. Pretransplant identification and management can avoid such complications. Here, we describe a case of APRT deficiency leading to crystal nephropathy and end-stage renal failure in a patient who underwent a successful kidney transplant.

A cellular protection racket: How lysosomal Ca2+ fluxes prevent kidney injury.

LC3-lipidation is activated by lysosomal damage by mechanisms that are unknown and divergent from canonical autophagy. In this study, Nakamura et al, show that lysosomal damage induced by lysosomotropic agents or oxalate in renal proximal tubule cells causes lipidated LC3 to insert into the lysosomal membrane to activate TRPML1 channels and release Ca2+ from lysosomes. This leads to TFEB dephosphorylation and translocation into the nucleus which results in clearance of damaged lysosomes and their contents which may reduce the deleterious effects of crystal nephropathy.

[Amoxicillin induced crystal nephropathy : Monitoring of residual plasma levels]. / Cristalluries sous amoxicilline : intérêt du monitoring des concentrations plasmatiques résiduelles.

Since 2010, a lot of cases of amoxicillin induced crystal nephropathy have been reported to the French pharmacovigilance centers partly due to the high doses recommended by infectious disease guidelines. Typical clinical presentation and exclusion of others toxics or immuno-allergic causes are mandatory to assess the diagnostic. Amoxicillin crystals are rarely found or searched and renal biopsy is not frequently performed due to technical reasons and prompt renal recovery after antibiotics withdrawal. Monitoring of residual plasma concentration is rarely used in clinical practice for diagnostic or prognostic interest. We present 9 consecutive cases of acute kidney injury suspected to be due to amoxicillin crystals with residuals plasma levels to disclose a predictive threshold of tubulopathy. All patients had a high residual rate at diagnosis but we cannot find a threshold that would allow to adapt the antibiotic dose, enhance hydratation and alkalinizide urine to increase the medication solubility and limit renal toxicity.