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Aim: Sodium‐glucose cotransporter 2 (SGLT2) inhibitors often cause a transient decrease in glomerular filtration rate (GFR) shortly after the initiation, referred to as the 'initial drop'. However, the clinical significance of this initial drop in real‐world practice remains unclear. Materials and Methods: Using the nationwide Japan Chronic Kidney Disease Database, we examined factors that affected the initial drop, in patients with chronic kidney disease (CKD) and type 2 diabetes mellitus (T2DM). We also evaluated the effects of the initial drop on a composite kidney outcome (a decline in GFR of ≥50% or progression to end‐stage kidney disease). Results: Data from 2053 patients with CKD and T2DM newly prescribed an SGLT2 inhibitor were analysed. The follow‐up period after SGLT2 inhibitor administration was 1015 days (interquartile range: 532, 1678). Multivariate linear regression models revealed that the concomitant use of the renin‐angiotensin system inhibitors and diuretics, urinary protein levels ≥2+, and changes in GFR before the initiation of the SGLT2 inhibitor were associated with a larger initial GFR decline (β = −0.609, p =.039; β = −2.298, p <.001; β = −0.936, p =.048; β = −0.079, p <.001, respectively). Patients in the quartile with the largest initial GFR decline experienced a higher incidence of the subsequent composite kidney outcome than those in the other quartiles (p <.001). Conclusions: The concomitant use of renin‐angiotensin system inhibitors and diuretics, higher urine protein levels and pre‐treatment GFR changes were associated with a larger initial GFR decline. Of these factors, the use of a diuretic had the largest effect. Furthermore, patients with CKD and T2DM experiencing an excessive initial GFR drop might be at a higher risk of adverse kidney outcomes. [ABSTRACT FROM AUTHOR]

Remdesivir, a prodrug of the nucleoside analog GS‐441524, plays a key role in the treatment of coronavirus disease 2019 (COVID‐19). However, owing to limited information on clinical trials and inexperienced clinical use, there is a lack of pharmacokinetic (PK) data in patients with COVID‐19 with special characteristics. In this study, we aimed to measure serum GS‐441524 concentrations and develop a population PK (PopPK) model. Remdesivir was administered at a 200 mg loading dose on the first day followed by 100 mg from day 2, based on the package insert, in patients with an estimated glomerular filtration rate (eGFR) greater than or equal to 30 ml/min. In total, 190 concentrations from 37 Japanese patients were used in the analysis. The GS‐441524 trough concentrations were significantly higher in the eGFR less than 60 ml/min group than in the eGFR greater than or equal to 60 ml/min group. Extracorporeal membrane oxygenation in four patients hardly affected the total body clearance (CL) and volume of distribution (Vd) of GS‐441524. A one‐compartment model described serum GS‐441524 concentration data. The CL and Vd of GS‐441524 were significantly affected by eGFR readjusted by individual body surface area and age, respectively. Simulations proposed a dose regimen of 200 mg on day 1 followed by 100 mg once every 2 days from day 2 in patients with an eGFR of 30 ml/min or less. In conclusion, we successfully established a PopPK model of GS‐441524 using retrospectively obtained serum GS‐441524 concentrations in Japanese patients with COVID‐19, which would be helpful for optimal individualized therapy of remdesivir. [ABSTRACT FROM AUTHOR]

Urinary fatty acid binding protein 1 (FABP1, also known as liver‐type FABP) has been implicated as a biomarker of acute kidney injury (AKI) in humans. However, the precise biological mechanisms underlying its elevation remain elusive. Here, we show that urinary FABP1 primarily reflects impaired protein reabsorption in proximal tubule epithelial cells (PTECs). Bilateral nephrectomy resulted in a marked increase in serum FABP1 levels, suggesting that the kidney is an essential organ for removing serum FABP1. Injected recombinant FABP1 was filtered through the glomeruli and robustly reabsorbed via the apical membrane of PTECs. Urinary FABP1 was significantly elevated in mice devoid of megalin, a giant endocytic receptor for protein reabsorption. Elevation of urinary FABP1 was also observed in patients with Dent disease, a rare genetic disease characterized by defective megalin function in PTECs. Urinary FABP1 levels were exponentially increased following acetaminophen overdose, with both nephrotoxicity and hepatotoxicity observed. FABP1‐deficient mice with liver‐specific overexpression of FABP1 showed a massive increase in urinary FABP1 levels upon acetaminophen injection, indicating that urinary FABP1 is liver‐derived. Lastly, we employed transgenic mice expressing diphtheria toxin receptor (DT‐R) either in a hepatocyte‐ or in a PTEC‐specific manner, or both. Upon administration of diphtheria toxin (DT), massive excretion of urinary FABP1 was induced in mice with both kidney and liver injury, while mice with either injury type showed marginal excretion. Collectively, our data demonstrated that intact PTECs have a considerable capacity to reabsorb liver‐derived FABP1 through a megalin‐mediated mechanism. Thus, urinary FABP1, which is synergistically enhanced by concurrent liver injury, is a biomarker for impaired protein reabsorption in AKI. These findings address the use of urinary FABP1 as a biomarker of histologically injured PTECs that secrete FABP1 into primary urine, and suggest the use of this biomarker to simultaneously monitor impaired tubular reabsorption and liver function. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland. [ABSTRACT FROM AUTHOR]

Fibroblasts reside in various organs and support tissue structure and homeostasis under physiological conditions. Phenotypic alterations of fibroblasts underlie the development of diverse pathological conditions, including organ fibrosis. Recent advances in single‐cell biology have revealed that fibroblasts comprise heterogeneous subpopulations with distinct phenotypes, which exert both beneficial and detrimental effects on the host organs in a context‐dependent manner. In the kidney, phenotypic alterations of resident fibroblasts provoke common pathological conditions of chronic kidney disease (CKD), such as renal anemia and peritubular capillary loss. Additionally, in aged injured kidneys, fibroblasts provide functional and structural supports for tertiary lymphoid tissues (TLTs), which serve as the ectopic site of acquired immune reactions in various clinical contexts. TLTs are closely associated with aging and CKD progression, and the developmental stages of TLTs reflect the severity of renal injury. In this review, we describe the current understanding of fibroblast heterogeneity both under physiological and pathological conditions, with special emphasis on fibroblast contribution to TLT formation in the kidney. Dissecting the heterogeneous characteristics of fibroblasts will provide a promising therapeutic option for fibroblast‐related pathological conditions, including TLT formation. [ABSTRACT FROM AUTHOR]

Epidemiological findings indicate that acute kidney injury (AKI) increases the risk for chronic kidney disease (CKD), although the molecular mechanism remains unclear. Genetic fate mapping demonstrated that nephrons, functional units in the kidney, are repaired by surviving nephrons after AKI. However, the cell population that repairs damaged nephrons and their repair capacity limitations remain controversial. To answer these questions, we generated a new transgenic mouse strain in which mature proximal tubules, the segment predominantly damaged during AKI, could be genetically labelled at desired time points. Using this strain, massive proliferation of mature proximal tubules is observed during repair, with no dilution of the genetic label after the repair process, demonstrating that proximal tubules are repaired mainly by their own proliferation. Furthermore, acute tubular injury caused significant shortening of proximal tubules associated with interstitial fibrosis, suggesting that proximal tubules have a limited capacity to repair. Understanding the mechanism of this limitation might clarify the mechanism of the AKI-to-CKD continuum. [ABSTRACT FROM AUTHOR]

Aim: The number of hemodialysis (HD) patients is increasing along with their mean age in Japan. The assessment of their psychosocial status and quality of life (QOL) is therefore becoming more and more important along with laboratory data or comorbidities. Methods: We examined the psychosocial status of 211 HD patients (72 elderly and 139 non-elderly) and compared the difference between elderly and non-elderly patients using a visual analogue scale (VAS). We then examined how QOL affected mortality rate in 3-year prospective follow up. We assessed 10 items of QOL: health condition, appetite, sleep, mood, memory, family relationships, friendship, economical status, life satisfaction in daily life, and happiness with qualified self-evaluating questionnaires along with laboratory data and comorbidities. Furthermore, we investigated the correlation between the scores of mood and geriatric depression scale (GDS)-15. Results: There was no difference in VAS scores between elderly and non-elderly patients. Lower VAS scores for appetite and mood correlated with higher mortality in HD patients, especially in the non-elderly. VAS scores for mood correlated with GDS-15 in HD patients. Conclusions: More attention should be paid to appetite and the diagnosis and therapy of depressive mood to improve the prognosis of HD patients, especially for the non-elderly. Geriatr Gerontol Int 2012; 12: 65-71. [ABSTRACT FROM AUTHOR]

Bone morphogenetic proteins (BMPs) are phylogenetically conserved signaling molecules that belong to the transforming growth factor (TGF)-β superfamily and are involved in the cascades of body patterning and morphogenesis. The activities of BMPs are precisely regulated at various stages, and extracellulary, mainly regulated by certain classes of molecules termed as BMP antagonists and pro-BMP factors. BMP antagonists inhibit BMP function by prohibiting them from binding their cognate receptors, whereas pro-BMP factors stimulate BMP function. In this review, the functions of these BMP regulators will be discussed. © 2009 International Union of Biochemistry and Molecular Biology, Inc. [ABSTRACT FROM AUTHOR]

Soluble fms-like tyrosine kinase-1 (sFlt1), a circulating vascular endothelial growth factor receptor 1 antagonist, is associated with the pathogenesis of pre-eclampsia. Extracorporeal removal of sFlt1 (sFlt1 apheresis) is emerging as a treatment for pre-eclampsia. We performed sFlt1 apheresis for a patient with very early onset pre-eclampsia, beginning at 15 weeks' gestation. She underwent sFlt1 apheresis 13 times from 19 to 23 weeks' gestation. The series of treatments lowered circulating sFlt1, stabilized blood pressure, reduced urinary protein, and preserved renal function, which contributed to a successful prolongation of pregnancy for 4 weeks and a live birth at 23+3 weeks' gestation. Further studies are necessary for clinical application of sFlt1 apheresis as sFlt1 might have a protective function for the placenta and fetus in pre-eclampsia. [ABSTRACT FROM AUTHOR]

Aim Methods Results Conclusion Recent evidence suggests that acute liver failure (ALF) in some patients may reflect a dysregulated immune response, and that corticosteroids improve survival of the native liver in ALF patients with high serum alanine aminotransferase levels, which are an indication of liver inflammation. However, it is unclear whether steroids are effective for pediatric acute liver failure (PALF). The aim of this retrospective case–control study is to examine whether steroid therapy for PALF accompanied by immune activation improves the survival of native liver and to identify factors that predict responses to steroid treatment.Of 38 patients with PALF treated at Kyoto University Hospital from February 2006 to August 2022, 19 receiving steroids who met the specific criteria for identifying the pathophysiology of immune activity in the liver (the “Steroid group”), and seven steroid‐free patients who also met the criteria (“Nonsteroid group”) were enrolled. Patients in the “Steroid group” were categorized as “responders” or “nonresponders” according to treatment outcome. Clinical and histological data were analyzed.Survival of the native liver in the Steroid group was significantly higher than that in the Nonsteroid group (68% vs. 0%, respectively; p = 0.0052). Nonresponders were significantly younger, with higher Model for End‐stage Liver Disease and pediatric end‐stage liver disease scores, higher prothrombin time – international normalized ratio, and higher serum ferritin levels than responders. Massive hepatic necrosis was more common in nonresponders.Steroid therapy is effective for PALF patients with liver inflammation; however, liver transplantation should be prioritized for young children with ALF accompanied by severe coagulopathy or massive hepatic necrosis. [ABSTRACT FROM AUTHOR]

Dialysis dependency is one of the leading causes of morbidity and mortality in the world, and once end-stage renal disease develops, it cannot be reversed by currently available therapy. Although the administration of large dose of bone morphogenetic protein-7 (BMP-7) has been shown to repair established renal injuries and improves renal function, pathophysiological role of endogenous BMP-7 and regulatory mechanism of its activities remain elusive. Here we show that uterine sensitization-associated gene-1 (USAG-1), novel BMP antagonist abundantly expressed in the kidney, is the central negative regulator of BMP function in the kidney, and that mice lacking USAG-1 ( USAG-1−/− mice) are resistant to kidney injuries. USAG-1−/− mice exhibited prolonged survival and preserved renal function in acute and chronic renal injuries. Renal BMP signaling, assessed by phosphorylation of Smad proteins, is significantly enhanced in USAG-1−/− mice during renal injury, indicating that the preservation of renal function is attributed to enhancement of endogenous BMP signaling. Furthermore, the administration of neutralizing antibody against BMP-7 abolished reno-protection in USAG-1−/− mice, indicating that USAG-1 plays a critical role in the modulation of reno-protective action of BMP, and that inhibition of USAG-1 will be promising means of development of novel treatment for kidney diseases. [ABSTRACT FROM AUTHOR]