{"title":"Updates on renal phosphate transport.","authors":"Carsten Alexande Wagner, Daniela Egli-Spichtig, Isabel Rubio-Aliaga","doi":"10.1097/MNH.0000000000001090","DOIUrl":"10.1097/MNH.0000000000001090","url":null,"abstract":"<p><strong>Purpose of review: </strong>The kidneys control systemic phosphate balance by regulating phosphate transporters mediating the reabsorption of inorganic phosphate (Pi). At least three different Na + -driven Pi cotransporters are located in the brush border membrane (BBM) of proximal tubule cells, NaPi-IIa (SLC34A1), NaPi-IIc (SLC34A3) and PiT-2 (SLC20A2). This review will discuss novel aspects of their regulation, pharmacology, and genetics.</p><p><strong>Recent findings: </strong>Renal NaPi transporters are not only acutely regulated by the phosphaturic hormones parathyroid hormone (PTH) and Fibroblast Growth Factor 23 (FGF23) but possibly also by further mechanisms. A role of inositol hexakisphosphate (IP6) kinases has been found and their deletion from kidneys causes hypophosphatemia, hyperphosphaturia, and bone demineralization. Inhibitors of NaPis elicit phosphaturia and may reduce levels of PTH and FGF23 in chronic kidney disease (CKD) models. The relevance of renal NaPi transporters is highlighted by loss-of-function mutations in SLC34 transporters and analysis of patients provides new insights into diseases caused by variants. Major manifestations include nephrocalcinosis and -lithiasis, rickets, and variants may predispose to an accelerated decline in kidney function.</p><p><strong>Summary: </strong>Renal Pi transporters are regulated, may provide novel drug targets for prevention or treatment of hyperphosphatemia, and contribute to the genetic risk to develop kidney stones and CKD.</p>","PeriodicalId":10960,"journal":{"name":"Current Opinion in Nephrology and Hypertension","volume":" ","pages":"269-275"},"PeriodicalIF":2.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143972792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Chronic kidney disease and sex dimorphism.","authors":"Sarah Abu Kar, Raymond C Harris","doi":"10.1097/MNH.0000000000001093","DOIUrl":"10.1097/MNH.0000000000001093","url":null,"abstract":"<p><strong>Purpose of review: </strong>This review highlights studies published in the last 18 months focusing on sex dimorphism in clinical and preclinical areas related to chronic kidney disease (CKD).</p><p><strong>Recent findings: </strong>Hypertension, cardiorenal disease, hormone exposure, heat stress and dietary intake are all risk factors with sexually dimorphic effects thus contributing differentially to the development of chronic kidney disease. In CKD, GFR decline and cardiovascular mortality are more pronounced in males. Females have higher STEMI related in hospital mortality. When on dialysis, females have higher cardiovascular events rate. Males develop anemia and hyperparathyroidism earlier. Hyperphosphatemia is more prevalent in males. Vitamin D deficiency is associated with CKD in males only. Males are more likely to develop severe sarcopenia. The renoprotective effects of estrogen or estrogen agonists are mediated in part through GPER. ET-1 dual antagonism offset the action of GPER. ET-1 dual antagonism abolished the sex differences in acclimation to high salt. Sodium transport and oxygen consumption across the different renal segments is sexually dimorphic. Sexually dimorphic gene expression is mostly seen in the proximal tubules and is under androgen control.</p><p><strong>Summary: </strong>The above findings emphasize the need to systematically include female models in preclinical and clinical research which will improve clinical management and allow for development and implementation of precision medicine tailored to sex.</p>","PeriodicalId":10960,"journal":{"name":"Current Opinion in Nephrology and Hypertension","volume":" ","pages":"314-321"},"PeriodicalIF":2.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143984480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Novel insights in the regulation of intercalated cell differentiation.","authors":"Yu Feng, Yanmiao Qi, Xiangjian Zheng","doi":"10.1097/MNH.0000000000001095","DOIUrl":"https://doi.org/10.1097/MNH.0000000000001095","url":null,"abstract":"<p><strong>Purpose of review: </strong>Kidney intercalated cells play critical roles in regulating body acid-base balance. We recently discovered Foxp1 and two downstream transcriptional factors Dmrt2 and Hmx2 are essential for intercalated cell differentiation. This review incorporates these findings with previous reports to add insights to the molecular regulation of intercalated cell differentiation.</p><p><strong>Recent findings: </strong>We reviewed the current understanding of intercalated cell differentiation and plasticity, and the contribution of single-cell sequencing to point to the existence of transitional cells during principal cell and intercalated cell differentiation or trans-differentiation. For molecular regulation of cell differentiation, we discuss how Notch and Foxi1 regulate principal cell/intercalated cell switch and intercalated cell differentiation, and the new finding of Foxp1 and downstream transcriptional factors in intercalated cell subtype specification.</p><p><strong>Summary: </strong>The differentiation and balance of principal cell and intercalated cell subtypes are the foundation for maintaining acid-base balance. A clear understanding of the cellular and molecular controls of these processes provides the basis for designing intervention approaches for metabolism acidosis or alkalosis and other related diseases.</p>","PeriodicalId":10960,"journal":{"name":"Current Opinion in Nephrology and Hypertension","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144224656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Agents to treat osteoporosis in chronic kidney disease.","authors":"Pascale Khairallah","doi":"10.1097/MNH.0000000000001091","DOIUrl":"https://doi.org/10.1097/MNH.0000000000001091","url":null,"abstract":"<p><strong>Purpose of review: </strong>Fracture risk is significantly elevated in patients with chronic kidney disease (CKD), yet the diagnosis and treatment of CKD-associated osteoporosis remain complex. This review addresses the current gaps in managing bone health in CKD and highlights emerging strategies in this high-risk population.</p><p><strong>Recent findings: </strong>Diagnosis of CKD-associated osteoporosis requires integration of imaging, bone turnover markers, and occasionally bone biopsy. Correction of mineral metabolism disturbances is foundational, while bone-targeted therapies must be carefully selected. Treatment strategies are informed by bone turnover status. Antiresorptives such as bisphosphonates and denosumab are used in high-turnover disease, and osteoanabolic agents such as teriparatide and romosozumab are promising for low-turnover disease.</p><p><strong>Summary: </strong>Management of osteoporosis in CKD requires individualized approaches based on bone turnover and mineral metabolism status. While several pharmacologic options exist, evidence from randomized trials in CKD populations is limited. Further research is needed to guide treatment selection, define well tolerated therapeutic targets, and improve skeletal outcomes in this vulnerable group.</p>","PeriodicalId":10960,"journal":{"name":"Current Opinion in Nephrology and Hypertension","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144076466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Calcium-binding protein 39 in with-no-lysine kinase signaling and the modulation of renal tubular transport.","authors":"Mohammed Z Ferdaus, Eric Delpire","doi":"10.1097/MNH.0000000000001083","DOIUrl":"https://doi.org/10.1097/MNH.0000000000001083","url":null,"abstract":"<p><strong>Purpose of review: </strong>The regulation of renal tubular transport is essential for maintaining electrolyte balance and blood pressure. Calcium-binding protein 39 (Cab39), also known as mouse protein-25 (MO25), plays a pivotal role in modulating this process through its interaction with WNK (with no lysine) kinases and Ste20-like kinases, including STE20/SPS1-related proline-alanine-rich kinase (SPAK) and oxidative stress response 1 (OSR1). By stabilizing and facilitating the activation of these kinases, Cab39 plays a crucial role in the regulation of key ion transporters, such as the sodium-chloride cotransporter (NCC) and the sodium-potassium-chloride cotransporters (NKCC1 and NKCC2). This review provides a comprehensive analysis of Cab39 structural properties, molecular interactions, and functional roles in renal physiology, emphasizing its significance in ion homeostasis.</p><p><strong>Recent findings: </strong>Studies reveal that Cab39 enhances SPAK activity up to 100-fold. Importantly, the role of Cab39 extends beyond simple kinase activation, as it supports kinase complex assembly and localization, enabling precise control over transporter regulation. Evidence also suggests that Cab39 may influence the regulation of NCC and NKCC2 through similar mechanisms, making it a promising target for therapeutic interventions in disorders such as hypertension and salt-wasting syndromes.</p><p><strong>Summary: </strong>The discovery of a small-molecule Cab39 inhibitor highlights its potential as a pharmacological target. Understanding the multifaceted functions of Cab39 may unlock novel strategies for managing renal and cardiovascular disorders.</p>","PeriodicalId":10960,"journal":{"name":"Current Opinion in Nephrology and Hypertension","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143962967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marieta P Theodorakopoulou, Fotini Iatridi, Pantelis A Sarafidis
{"title":"Aldosterone synthase inhibition in chronic kidney disease.","authors":"Marieta P Theodorakopoulou, Fotini Iatridi, Pantelis A Sarafidis","doi":"10.1097/MNH.0000000000001089","DOIUrl":"https://doi.org/10.1097/MNH.0000000000001089","url":null,"abstract":"<p><strong>Purpose: </strong>Chronic kidney disease (CKD) is associated with elevated cardiovascular risk and progression to kidney failure, despite advances in therapy with renin-angiotensin system inhibitors and sodium-glucose-co-transporter-2 inhibitors. Overactivation of the aldosterone pathway contributes to residual cardiorenal risk. Nonsteroidal mineralocorticoid receptor antagonists (MRAs) have shown efficacy in reducing cardiorenal outcomes in patients with albuminuric diabetic kidney disease, providing a rationale to explore broader aldosterone pathway inhibition in CKD.</p><p><strong>Recent findings: </strong>While steroidal MRAs are effective, their use is often limited by hormonal side effects and risk of hyperkalemia. Finerenone, a selective nonsteroidal MRA, showed cardiovascular and renal benefit in CKD patients with diabetes, although with only modest BP-lowering effects. Its role in nondiabetic populations and in those with lower levels of albuminuria remains to be determined. More recently, aldosterone synthase inhibitors (ASIs) have emerged as promising agents that directly suppress aldosterone production. Early-phase studies in patients with CKD, with or without diabetes, have shown reductions in albuminuria and BP, with a favorable safety profile.</p><p><strong>Summary: </strong>Direct inhibition of aldosterone synthesis may provide a novel and complementary strategy to reduce residual cardiorenal risk in CKD. Ongoing phase 3 trials will be key to defining the clinical utility of ASIs and their integration into future treatment paradigms.</p>","PeriodicalId":10960,"journal":{"name":"Current Opinion in Nephrology and Hypertension","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143989365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"APOL1 testing in clinical practice and opportunities for new therapies.","authors":"Taewoo Lee, Lijun Ma, Barry I Freedman","doi":"10.1097/MNH.0000000000001082","DOIUrl":"https://doi.org/10.1097/MNH.0000000000001082","url":null,"abstract":"<p><strong>Purpose of review: </strong>The spectrum of kidney diseases caused by variation in the apolipoprotein L1 (APOL1) gene was identified in 2010 among patients with recent African ancestry. In the United States, inheriting two APOL1 risk variants (high-risk genotypes) markedly increases risk for solidified glomerulosclerosis, focal segmental glomerulosclerosis, collapsing glomerulopathy, lupus nephritis, and sickle cell nephropathy. Kidneys from African American deceased donors with APOL1 high-risk genotypes also fail more rapidly after transplant. One risk variant increases nephropathy risk in Africa. This review focuses on novel therapies targeting APOL1 and the changing landscape of APOL1 genotyping in patients at risk for APOL1-mediated kidney disease (AMKD).</p><p><strong>Recent findings: </strong>Renin-angiotensin-aldosterone system blockade and sodium-glucose cotransporter 2 inhibitors slow nephropathy progression but are not curative. Medications directly targeting APOL1 mRNA and blocking APOL1 protein effects are undergoing clinical trials in AMKD, including APOL1 small molecule inhibitors, an APOL1 antisense oligonucleotide, and a Janus kinase (JAK) signaling inhibitor to reduce APOL1 expression. Early results are promising and provide hope for well tolerated and effective therapies. If successful, more patients will need to be considered for APOL1 genotyping, and our approach to diagnosing and treating chronic kidney disease in populations with recent African ancestry will change dramatically.</p><p><strong>Summary: </strong>Mechanisms of APOL1 risk variant nephrotoxicity remain unclear; nonetheless, specific therapies for AMKD show great promise and may improve understanding of disease processes. With ongoing clinical trials and the potential for effective AMKD treatments, more widespread APOL1 genotyping will likely be needed.</p>","PeriodicalId":10960,"journal":{"name":"Current Opinion in Nephrology and Hypertension","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143982823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Alport syndrome: an update.","authors":"Judy Savige","doi":"10.1097/MNH.0000000000001063","DOIUrl":"10.1097/MNH.0000000000001063","url":null,"abstract":"<p><strong>Purpose of review: </strong>The recent widespread availability of genetic testing has resulted in the diagnosis of many more people with Alport syndrome. This increased recognition has been paralleled by advances in understanding clinical consequences, genotype-phenotype correlations and in the development of new therapies.</p><p><strong>Recent findings: </strong>These include the international call for a change of name to 'Alport spectrum' which better reflects the diverse clinical features seen with autosomal dominant and X-linked Alport syndrome; the demonstration of how common Alport syndrome is in people with haematuria, proteinuria, or kidney failure; the inability of current genetic testing to detect all pathogenic variants in suspected Alport syndrome; the different genotype-phenotype correlations for autosomal dominant and X-linked disease; and the novel treatments that are available including SGLT2 inhibitors for persistent albuminuria despite renin-angiotensin-aldosterone blockade, as well as early studies of gene-modifying agents.</p><p><strong>Summary: </strong>Autosomal dominant Alport syndrome is the commonest genetic kidney disease and X-linked Alport syndrome is the second commonest genetic cause of kidney failure. Both these diseases are frequently seen in the renal clinic, and clinicians should be aware of their likelihood in a person with persistent glomerular haematuria, proteinuria or kidney failure. Autosomal dominant Alport syndrome is so common that it also occurs coincidentally in other kidney diseases especially IgA nephropathy.</p>","PeriodicalId":10960,"journal":{"name":"Current Opinion in Nephrology and Hypertension","volume":" ","pages":"206-211"},"PeriodicalIF":2.2,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143001820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The history and future of online hemodiafiltration and online solutions in North America.","authors":"Clement Leduc, Narumi Tomisawa, Claudio Ronco, Kamyar Kalantar-Zadeh","doi":"10.1097/MNH.0000000000001051","DOIUrl":"10.1097/MNH.0000000000001051","url":null,"abstract":"<p><strong>Purpose of review: </strong>Online hemodiafiltration (OL-HDF) is a type of outpatient intermittent dialysis therapy using purified online dialysis fluid sourced from the city water supply. OL-HDF has been widely practiced in Europe and Japan, and its clinical effects have been reported for prevention of dialysis amyloidosis, inflammation, and dialysis hypotension.</p><p><strong>Recent findings: </strong>A randomized controlled trial of all-cause mortality in postdilution OL-HDF and high-flux hemodialysis groups with replacement fluid volumes >23 l/session (CONVINCE study) reported a lower risk of all-cause mortality with OL-HDF compared to conventional hemodialysis. Whereas USA had not previously adopted OL-HDF, in February 2024 Fresenius' 5008K received 510K FDA approval, Although efforts to purify dialysis water and systems using dialysis fluid for HDF, such as those from Aksys (2002) and Nephros (2012), had been made in the past in the USA, they did not gain widespread adoption. Neighboring Canada has been conducting OL-HDF using the Gambro AK200 (1999), Baxter Artis (2009), B. Braun Dialog+ (2010), B. Braun Dialog IQ (2021) and the Fresenius 5008 (2013), all of which have received Health Canada approval for OL-HDF.</p><p><strong>Summary: </strong>OL-HDF's introduction to the USA represents both a challenge and an opportunity for patient care and the nephrology community. As a potentially superior treatment for ESRD patients, OL-HDF enables larger volumes of exchange, reduces costs by creating online solutions to replace expensive offline fluids, makes HDF therapy affordable for outpatient setting, and may improve survival and quality of life. However, significant barriers - ranging from regulatory and reimbursement hurdles to infrastructural inadequacies - must be addressed. Whether OL-HDF can finally emerge as a transformational renal replacement therapy after its entry to the US healthcare system remains to be determined.</p>","PeriodicalId":10960,"journal":{"name":"Current Opinion in Nephrology and Hypertension","volume":" ","pages":"254-258"},"PeriodicalIF":2.2,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143440163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Challenges in standardizing preimplantation kidney biopsy assessments and the potential of AI-Driven solutions.","authors":"Karolien Wellekens, Priyanka Koshy, Maarten Naesens","doi":"10.1097/MNH.0000000000001064","DOIUrl":"10.1097/MNH.0000000000001064","url":null,"abstract":"<p><strong>Purpose of review: </strong>This review explores the variability in preimplantation kidney biopsy processing methods, emphasizing their impact on histological interpretation and allocation decisions driven by biopsy findings. With the increasing use of artificial intelligence (AI) in digital pathology, it is timely to evaluate whether these advancements can overcome current challenges and improve organ allocation amidst a growing organ shortage.</p><p><strong>Recent findings: </strong>Significant inconsistencies exist in biopsy methodologies, including core versus wedge sampling, frozen versus paraffin-embedded processing, and variability in pathologist expertise. These differences complicate study comparisons and limit the reproducibility of histological assessments. Emerging AI-driven tools and digital pathology show potential for standardizing assessments, enhancing reproducibility, and reducing dependence on expert pathologists. However, few studies have validated their clinical utility or demonstrated their predictive performance for long-term outcomes.</p><p><strong>Summary: </strong>Novel AI-driven tools hold promise for improving the standardization and accuracy of preimplantation kidney biopsy assessments. However, their clinical application remains limited due to a lack of proven associations with posttransplant outcomes and insufficient evaluation of predictive performance metrics. Future research should prioritize longitudinal studies using large-scale datasets, rigorous validation, and comprehensive assessments of predictive performance for both short- and long-term outcomes to fully establish their clinical utility.</p>","PeriodicalId":10960,"journal":{"name":"Current Opinion in Nephrology and Hypertension","volume":" ","pages":"185-190"},"PeriodicalIF":2.2,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143001823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}