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1.
BMC Nutr ; 10(1): 95, 2024 Jul 04.
Article in English | MEDLINE | ID: mdl-38965589

ABSTRACT

INTRODUCTION: It is unclear how dietary intake changes after sodium-glucose cotransporter 2 inhibitor (SGLT2i) treatment is started in patients with type 2 diabetes. METHODS: We performed a non-controlled, open-label study that enrolled 51 patients with type 2 diabetes. The patients were newly administered empagliflozin, and their dietary habits were examined using a self-administered diet history questionnaire at the beginning of the study and after 24 weeks. We investigated the association of changes in HbA1c and body weight with changes in energy, nutrient, and food group intakes. RESULTS: At 24 weeks after the start of the study, HbA1c improved significantly and body weight decreased. In the food group, only the intake of confectionery increased, and there were no significant differences in the association between changes in HbA1c and body weight and changes in energy, nutrient, and food group intakes after 24 weeks. However, a significant negative correlation was found between change in HbA1c after 4 weeks and change in energy intake after 24 weeks, and principal component analysis showed an association between change in HbA1c levels after 4 weeks and change in energy intake and some food group intakes including confectionery after 24 weeks. CONCLUSION: In this study, after 24 weeks of treatment with empagliflozin, only intake of confectionery increased. Early assessment by dietitians after initiation of SGLT2i treatment might be important because our data suggested that the reduction in blood glucose levels after the start of empagliflozin was associated with a subsequent increase in energy intake. TRIAL REGISTRATION: University Hospital Medical Information Network-Clinical Trials Registry (UMIN-CTR) on September 5, 2016 (registration ID, UMIN000002309|| http://www.umin.ac.jp/ctr/ ).

2.
Proc Natl Acad Sci U S A ; 121(22): e2318859121, 2024 May 28.
Article in English | MEDLINE | ID: mdl-38771880

ABSTRACT

Megalin (low-density lipoprotein receptor-related protein 2) is a giant glycoprotein of about 600 kDa, mediating the endocytosis of more than 60 ligands, including those of proteins, peptides, and drug compounds [S. Goto, M. Hosojima, H. Kabasawa, A. Saito, Int. J. Biochem. Cell Biol. 157, 106393 (2023)]. It is expressed predominantly in renal proximal tubule epithelial cells, as well as in the brain, lungs, eyes, inner ear, thyroid gland, and placenta. Megalin is also known to mediate the endocytosis of toxic compounds, particularly those that cause renal and hearing disorders [Y. Hori et al., J. Am. Soc. Nephrol. 28, 1783-1791 (2017)]. Genetic megalin deficiency causes Donnai-Barrow syndrome/facio-oculo-acoustico-renal syndrome in humans. However, it is not known how megalin interacts with such a wide variety of ligands and plays pathological roles in various organs. In this study, we elucidated the dimeric architecture of megalin, purified from rat kidneys, using cryoelectron microscopy. The maps revealed the densities of endogenous ligands bound to various regions throughout the dimer, elucidating the multiligand receptor nature of megalin. We also determined the structure of megalin in complex with receptor-associated protein, a molecular chaperone for megalin. The results will facilitate further studies on the pathophysiology of megalin-dependent multiligand endocytic pathways in multiple organs and will also be useful for the development of megalin-targeted drugs for renal and hearing disorders, Alzheimer's disease [B. V. Zlokovic et al., Proc. Natl. Acad. Sci. U.S.A. 93, 4229-4234 (1996)], and other illnesses.


Subject(s)
Cryoelectron Microscopy , Low Density Lipoprotein Receptor-Related Protein-2 , Low Density Lipoprotein Receptor-Related Protein-2/metabolism , Low Density Lipoprotein Receptor-Related Protein-2/genetics , Animals , Humans , Rats , Ligands , Endocytosis , Agenesis of Corpus Callosum/metabolism , Agenesis of Corpus Callosum/genetics , Renal Tubular Transport, Inborn Errors , Myopia , Hernias, Diaphragmatic, Congenital , Proteinuria , Hearing Loss, Sensorineural
3.
J Pathol ; 263(3): 315-327, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38721910

ABSTRACT

Hemolysis-induced acute kidney injury (AKI) is attributed to heme-mediated proximal tubule epithelial cell (PTEC) injury and tubular cast formation due to intratubular protein condensation. Megalin is a multiligand endocytic receptor for proteins, peptides, and drugs in PTECs and mediates the uptake of free hemoglobin and the heme-scavenging protein α1-microglobulin. However, understanding of how megalin is involved in the development of hemolysis-induced AKI remains elusive. Here, we investigated the megalin-related pathogenesis of hemolysis-induced AKI and a therapeutic strategy using cilastatin, a megalin blocker. A phenylhydrazine-induced hemolysis model developed in kidney-specific mosaic megalin knockout (MegKO) mice confirmed megalin-dependent PTEC injury revealed by the co-expression of kidney injury molecule-1 (KIM-1). In the hemolysis model in kidney-specific conditional MegKO mice, the uptake of hemoglobin and α1-microglobulin as well as KIM-1 expression in PTECs was suppressed, but tubular cast formation was augmented, likely due to the nonselective inhibition of protein reabsorption in PTECs. Quartz crystal microbalance analysis revealed that cilastatin suppressed the binding of megalin with hemoglobin and α1-microglobulin. Cilastatin also inhibited the specific uptake of fluorescent hemoglobin by megalin-expressing rat yolk sac tumor-derived L2 cells. In a mouse model of hemolysis-induced AKI, repeated cilastatin administration suppressed PTEC injury by inhibiting the uptake of hemoglobin and α1-microglobulin and also prevented cast formation. Hemopexin, another heme-scavenging protein, was also found to be a novel ligand of megalin, and its binding to megalin and uptake by PTECs in the hemolysis model were suppressed by cilastatin. Mass spectrometry-based semiquantitative analysis of urinary proteins in cilastatin-treated C57BL/6J mice indicated that cilastatin suppressed the reabsorption of a limited number of megalin ligands in PTECs, including α1-microglobulin and hemopexin. Collectively, cilastatin-mediated selective megalin blockade is an effective therapeutic strategy to prevent both heme-mediated PTEC injury and cast formation in hemolysis-induced AKI. © 2024 The Pathological Society of Great Britain and Ireland.


Subject(s)
Acute Kidney Injury , Hemolysis , Kidney Tubules, Proximal , Low Density Lipoprotein Receptor-Related Protein-2 , Mice, Knockout , Animals , Low Density Lipoprotein Receptor-Related Protein-2/metabolism , Low Density Lipoprotein Receptor-Related Protein-2/genetics , Acute Kidney Injury/metabolism , Acute Kidney Injury/pathology , Kidney Tubules, Proximal/metabolism , Kidney Tubules, Proximal/pathology , Kidney Tubules, Proximal/drug effects , Hemoglobins/metabolism , Mice , Cilastatin/pharmacology , Disease Models, Animal , Phenylhydrazines , Mice, Inbred C57BL , Male , Hepatitis A Virus Cellular Receptor 1/metabolism , Alpha-Globulins/metabolism , Humans
4.
Clin Exp Nephrol ; 28(3): 254-260, 2024 Mar.
Article in English | MEDLINE | ID: mdl-37982979

ABSTRACT

BACKGROUND: There have been no coherent reports on the effects of dietary intake during hemodialysis in Japan. Furthermore, few studies have reported the impact of the COVID-19 pandemic on them. This study aimed to investigate dietary intake during hemodialysis and its impact on the spread of COVID-19. METHODS: This consecutive cross-sectional study included a survey of all hemodialysis facilities in the Niigata Prefecture. The survey form was sent via e-mail or fax. RESULTS: Fifty four facilities (98%) responded to the 2018 survey. Twenty-eight facilities (52%) provided meals, with 18% of all patients undergoing dialysis and 41% of patients undergoing nocturnal dialysis consuming meals during hemodialysis. In the 2020 survey, the number of facilities decreased to 17 (33%), and the number of all patients undergoing dialysis and nocturnal dialysis consuming meals decreased to 13% and 32%, respectively. In the 2022 survey, the number of facilities decreased to 14 (27%), and the number of all patients undergoing dialysis and nocturnal dialysis decreased to 9% and 19%, respectively. CONCLUSION: The COVID-19 pandemic has caused a decrease in both facilities serving meals and patients' food consumption during hemodialysis. To prevent the loss of meal opportunities, establishing safe methods for food intake and alternatives in hemodialysis facilities is necessary.


Subject(s)
COVID-19 , Renal Dialysis , Humans , Japan/epidemiology , Cross-Sectional Studies , Pandemics , COVID-19/epidemiology , Eating , Surveys and Questionnaires
5.
J Hypertens ; 41(11): 1831-1843, 2023 11 01.
Article in English | MEDLINE | ID: mdl-37682076

ABSTRACT

BACKGROUND: Kidney angiotensin (Ang) II is produced mainly from liver-derived, glomerular-filtered angiotensinogen (AGT). Podocyte injury has been reported to increase the kidney Ang II content and induce Na + retention depending on the function of megalin, a proximal tubular endocytosis receptor. However, how megalin regulates the renal content and action of Ang II remains elusive. METHODS: We used a mass spectrometry-based, parallel reaction-monitoring assay to quantitate Ang II in plasma, urine, and kidney homogenate of kidney-specific conditional megalin knockout (MegKO) and control (Ctl) mice. We also evaluated the pathophysiological changes in both mouse genotypes under the basal condition and under the condition of increased glomerular filtration of AGT induced by administration of recombinant mouse AGT (rec-mAGT). RESULTS: Under the basal condition, plasma and kidney Ang II levels were comparable in the two mouse groups. Ang II was detected abundantly in fresh spot urine in conditional MegKO mice. Megalin was also found to mediate the uptake of intravenously administered fluorescent Ang II by PTECs. Administration of rec-mAGT increased kidney Ang II, exerted renal extracellular signal-regulated kinase 1/2 (ERK1/2) signaling, activated proximal tubular Na + -H + exchanger 3 (NHE3), and decreased urinary Na + excretion in Ctl mice, whereas these changes were suppressed but urinary Ang II was increased in conditional MegKO mice. CONCLUSION: Increased glomerular filtration of AGT is likely to augment Ang II production in the proximal tubular lumen. Thus, megalin-dependent Ang II uptake should be involved in the ERK1/2 signaling that activates proximal tubular NHE3 in vivo , thereby causing Na + retention.


Subject(s)
Angiotensin II , Angiotensinogen , Animals , Mice , Angiotensin II/pharmacology , Angiotensinogen/genetics , Angiotensinogen/metabolism , Kidney Tubules, Proximal , Low Density Lipoprotein Receptor-Related Protein-2/genetics , Low Density Lipoprotein Receptor-Related Protein-2/metabolism , MAP Kinase Signaling System , Mitogen-Activated Protein Kinase 3/metabolism , Sodium/metabolism , Sodium-Hydrogen Exchanger 3/metabolism
6.
Int J Biochem Cell Biol ; 157: 106393, 2023 04.
Article in English | MEDLINE | ID: mdl-36863658

ABSTRACT

The large (∼600 kDa) endocytosis receptor megalin/low-density lipoprotein receptor-related protein 2 is highly expressed at the apical membrane of proximal tubular epithelial cells (PTECs). Megalin plays an important role in the endocytosis of various ligands via interactions with intracellular adaptor proteins, which mediate the trafficking of megalin in PTECs. Megalin mediates the retrieval of essential substances, including carrier-bound vitamins and elements, and impairment of the endocytic process may result in the loss of those substances. In addition, megalin reabsorbs nephrotoxic substances such as antimicrobial (colistin, vancomycin, and gentamicin) or anticancer (cisplatin) drugs and advanced glycation end product-modified or fatty acid-containing albumin. The megalin-mediated uptake of these nephrotoxic ligands causes metabolic overload in PTECs and leads to kidney injury. Blockade or suppression of the megalin-mediated endocytosis of nephrotoxic substances may represent a novel therapeutic strategy for drug-induced nephrotoxicity or metabolic kidney disease. Megalin reabsorbs urinary biomarker proteins such as albumin, α1-microglobulin, ß2-microglobulin, and liver-type fatty acid-binding protein; thus, the above-mentioned megalin-targeted therapy may have an effect on the urinary excretion of these biomarkers. We have previously established a sandwich enzyme-linked immunosorbent assay to measure the ectodomain (A-megalin) and full-length (C-megalin) forms of urinary megalin using monoclonal antibodies against the amino- and carboxyl-terminals of megalin, respectively, and reported their clinical usefulness. In addition, there have been reports of patients with novel pathological anti-brush border autoantibodies targeting megalin in the kidney. Even with these breakthroughs in the characterization of megalin, a large number of issues remain to be addressed in future research.


Subject(s)
Kidney Tubules, Proximal , Low Density Lipoprotein Receptor-Related Protein-2 , Humans , Albumins/metabolism , Biomarkers/metabolism , Endocytosis , Kidney/metabolism , Kidney Tubules, Proximal/metabolism , Ligands , Low Density Lipoprotein Receptor-Related Protein-2/metabolism
7.
Hum Genome Var ; 10(1): 5, 2023 Feb 02.
Article in English | MEDLINE | ID: mdl-36732323

ABSTRACT

We present a family of two female Alport syndrome patients with a family history of impaired glucose tolerance. Whole exome sequencing identified a novel heterozygous variant of COL4A5 NM_033380.3: c.2636 C > A (p.S879*) and a rare variant of GCK NM_001354800.1: c.1135 G > A (p.A379T) as the causes of Alport syndrome and monogenic diabetes, respectively. Two independent pathogenic variants affected the clinical phenotypes. Clinical next-generation sequencing is helpful for identifying the causes of patients' manifestations.

8.
CEN Case Rep ; 12(3): 311-317, 2023 08.
Article in English | MEDLINE | ID: mdl-36574195

ABSTRACT

Idiopathic nodular glomerulosclerosis has a poor renal prognosis and is characterized by diffuse nodular glomerulosclerotic lesions in the absence of diabetic mellitus. Here, we report the case of a 69-year-old woman with no smoking history who developed renal dysfunction and proteinuria in the absence of overt diabetes or obesity. A biopsy specimen showed nodular mesangial sclerosis with arteriolar hyalinosis and severe large-vessel arteriosclerosis, leading to a diagnosis of idiopathic nodular glomerulosclerosis. Addition of esaxerenone to her existing renin-angiotensin-aldosterone inhibitor therapy led to a rapid decrease in the proteinuria levels and the maintenance of renal function without any complications for more than a year. The results suggest that intensive renin-angiotensin-aldosterone blockade might be an effective treatment for idiopathic nodular glomerulosclerosis.


Subject(s)
Arteriosclerosis , Diabetic Nephropathies , Female , Humans , Aged , Diabetic Nephropathies/diagnosis , Renin-Angiotensin System , Renin , Aldosterone/pharmacology , Arteriosclerosis/complications , Arteriosclerosis/pathology , Proteinuria/diagnosis , Proteinuria/drug therapy , Proteinuria/etiology , Angiotensins/pharmacology
9.
Kidney360 ; 3(11): 1861-1870, 2022 11 24.
Article in English | MEDLINE | ID: mdl-36514407

ABSTRACT

Background: The benefits of dietary protein restriction in CKD remain unclear, largely due to inadequate adherence in most clinical trials. We examined whether low-protein rice (LPR) previously developed to reduce the protein content of rice, a major staple food, would help improve adherence to dietary protein restriction. Methods: This open-label, multicenter, randomized, controlled trial evaluated the efficacy of LPR use for reducing dietary protein intake (DPI) in patients with CKD stages G3aA2-G4. Participants were randomly assigned in a 1:1 ratio to an LPR or control group and were followed up for 24 weeks. Both groups received regular counseling by dietitians to help achieve a target DPI of 0.7 g/kg ideal body weight (IBW) per day. The amount of protein in LPR is about 4% of that in ordinary rice, and the participants in the LPR group were instructed to consume LPR with at least two meals per day. The primary outcome was estimated dietary protein intake (eDPI) determined using the Maroni formula. The secondary outcomes included creatinine clearance (CCr) and urinary protein on the basis of 24-hour urine collection. Results: In total, 51 patients were randomized to either the LPR group or the control group. At baseline, mean age was 62.5 years, 70% were men, mean CCr was 52.0 ml/min, and mean eDPI was 0.99 g/kg IBW per day. At 24 weeks, mean eDPI decreased to 0.80 g/kg IBW per day in the LPR group and to 0.91 g/kg IBW per day in the control group, giving a between-group difference of 0.11 g/kg IBW per day (95% confidence interval, 0.03 to 0.19 g/kg IBW per day; P=0.006). There was no significant between-group difference in CCr, but urinary protein was lower at 24 weeks in the LPR group than in the control group. Conclusions: LPR is a feasible tool for efficiently reducing DPI in patients with CKD. Clinical Trial registry name and registration number: Randomized, Multicenter, Controlled Study for the Efficacy of Low-Protein Rice Diet in Patients with Chronic Kidney Disease, UMIN000015630.


Subject(s)
Oryza , Renal Insufficiency, Chronic , Male , Humans , Middle Aged , Female , Diet, Protein-Restricted , Dietary Proteins
10.
J Diabetes Complications ; 36(11): 108312, 2022 11.
Article in English | MEDLINE | ID: mdl-36228564

ABSTRACT

AIMS: Megalin, a proximal tubular endocytosis receptor, is excreted in urine in two forms: ectodomain (A-megalin) and full-length (C-megalin). We explored whether urinary megalin levels can be used as independent prognostic biomarkers in the progression of diabetic kidney disease (DKD). METHODS: The associations between baseline urinary A-megalin/creatinine (Cr) and/or C-megalin/Cr levels and the subsequent estimated glomerular filtration rate (eGFR) slope were analyzed using a generalized estimating equation. Patients were categorized into higher or lower groups based on the optimal cutoff values, obtained from a receiver operating characteristic curve, of the two forms of urinary megalin. RESULTS: We retrospectively analyzed 188 patients with type 2 diabetes. The eGFR slopes of the higher A-megalin/Cr and higher C-megalin/Cr groups were - 0.904 and -0.749 ml/min/1.73 m2/year steeper than those of the lower groups, respectively. Moreover, the eGFR slope was -1.888 ml/min/1.73 m2/year steeper in the group with both higher A- and higher C-megalin/Cr than in the other group. These results remained significant when adjusted for known urinary biomarkers (albumin, α1-microglobulin, ß2-microglobulin, and N-acetyl-ß-d-glucosaminidase). CONCLUSIONS: Urinary A- and C-megalin/Cr levels are likely to be prognostic biomarkers in the progression of DKD independent of other urinary biomarkers.


Subject(s)
Diabetes Mellitus, Type 2 , Diabetic Nephropathies , Humans , Low Density Lipoprotein Receptor-Related Protein-2 , Diabetic Nephropathies/diagnosis , Retrospective Studies , Diabetes Mellitus, Type 2/complications , Diabetes Mellitus, Type 2/diagnosis , Diabetes Mellitus, Type 2/urine , Glomerular Filtration Rate , Biomarkers/urine , Disease Progression
11.
Diabetol Metab Syndr ; 14(1): 9, 2022 Jan 15.
Article in English | MEDLINE | ID: mdl-35033174

ABSTRACT

BACKGROUND: Although metabolic syndrome traits are risk factors for chronic kidney disease, few studies have examined their association with urinary biomarkers. METHODS: Urinary biomarkers, including A-megalin, C-megalin, podocalyxin, albumin, α1-microglobulin, ß2-microglobulin, and N-acetyl-ß-D-glucosaminidase, were cross-sectionally assessed in 347 individuals (52.7% men) with a urine albumin-to-creatinine ratio (ACR) < 300 mg/g in a health checkup. Metabolic syndrome traits were adopted from the National Cholesterol Education Program (third revision) of the Adult Treatment Panel criteria modified for Asians. RESULTS: Participants had a mean body mass index, estimated glomerular filtration rate (eGFR), and median ACR of 23.0 kg/m2, 74.8 mL/min/1.73 m2, and 7.5 mg/g, respectively. In age- and sex-adjusted logistic regression analysis, A-megalin and albumin were significantly associated with the clustering number of metabolic syndrome traits (3 or more). After further adjustment with eGFR, higher quartiles of A-megalin and albumin were each independently associated with the clustering number of metabolic syndrome traits (adjusted odds ratio for A-megalin: 1.30 per quartile, 95% CI 1.03-1.64; albumin: 1.42 per quartile, 95% CI 1.12-1.79). CONCLUSIONS: Both urinary A-megalin and albumin are associated with the clustering number of metabolic syndrome traits. Further research on urinary A-megalin is warranted to examine its role as a potential marker of kidney damage from metabolic risk factors.

12.
J Am Nutr Assoc ; 41(7): 668-678, 2022.
Article in English | MEDLINE | ID: mdl-34424818

ABSTRACT

Chronic kidney disease (CKD) impairs the anti-inflammatory effects of high-density lipoprotein (HDL) and increases cardiovascular mortality. Though the potential role of dietary interventions to manage HDL is well studied, the clinical trials aimed to increase HDL levels have failed to reduce cardiovascular risk, rendering HDL function to be explored as a more relevant clinical parameter. This study investigates the effects of rice endosperm protein (REP), a plant-based protein, on the anti-inflammatory properties of HDL and renal injury-driven atherosclerosis in comparison with casein, an animal protein.Ten-week-old apolipoprotein E-deficient hyperlipidemic mice underwent uninephrectomy. The mice (n = 6 each) were pair-fed a normal casein-based diet or a REP-based diet (both with 20.0% protein content) for seven weeks. Atherosclerotic lesions were detected by en face Sudan IV staining of the aorta.The number and sizes of the atherosclerotic lesions were significantly lower in the REP-based diet-fed group than the casein-based diet-fed group (p = 0.038). However, the REP-based diet neither elicited an ameliorative effect on kidney function or histology nor impacted the cholesterol profiles. Furthermore, HDL from the REP-based diet-fed mice significantly suppressed the inflammatory cytokine response of human umbilical vein endothelial cells than that from the casein-based diet-fed mice (MCP-1, p = 0.010; IL-6, p = 0.011; IL-1ß, p = 0.028).The REP-based diet has a higher potential to lessen the atherosclerotic lesions accelerated by renal mass reduction than a casein-based diet, which could be associated with the anti-inflammatory effects of HDL.


Subject(s)
Atherosclerosis , Oryza , Animals , Anti-Inflammatory Agents/pharmacology , Atherosclerosis/pathology , Caseins/pharmacology , Cholesterol , Disease Models, Animal , Endosperm/metabolism , Endothelial Cells/metabolism , Humans , Interleukin-6 , Lipoproteins, HDL , Mice , Mice, Knockout , Oryza/metabolism , Plant Proteins
13.
Kidney Blood Press Res ; 46(5): 652-656, 2021.
Article in English | MEDLINE | ID: mdl-34515141

ABSTRACT

BACKGROUND: Recently, attention has been focused on the effect of glucagon on blood glucose variability. The dynamics of glucagon have attracted attention as a new target in the treatment of diabetes patients. However, the dynamics of glucagon in hemodialysis (HD) patients with type 2 diabetes mellitus (T2DM) remain unclear. OBJECTIVES: The aim of this study was to assess the dynamics of glucagon in HD patients with T2DM. MATERIALS AND METHODS: We measured plasma glucagon in HD patients with T2DM by liquid chromatography-high-resolution mass spectrometry (LC-HRMS), sandwich enzyme-linked immunosorbent assay (ELISA), and radioimmunoassay (RIA). The glucagon levels measured by each method were compared. We used the glucagon levels determined by our developed LC-HRMS method as the standard in this study. RESULTS: Plasma glucagon levels measured by LC-HRMS before HD were significantly higher than those measured after HD. Plasma glucagon levels measured using sandwich ELISA had a significantly higher correlation with those measured using LC-HRMS compared with RIA. CONCLUSIONS: This was the first study to assess glucagon levels in HD patients with T2DM using LC-HRMS, which is considered a highly accurate method. Sandwich ELISA was shown to measure glucagon levels accurately as well.


Subject(s)
Diabetes Mellitus, Type 2/blood , Glucagon/blood , Renal Dialysis , Aged , Chromatography, Liquid , Female , Humans , Male , Mass Spectrometry , Middle Aged
14.
J Pathol ; 255(4): 362-373, 2021 12.
Article in English | MEDLINE | ID: mdl-34370295

ABSTRACT

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.


Subject(s)
Acute Kidney Injury , Biomarkers/urine , Fatty Acid-Binding Proteins/urine , Liver Diseases , Animals , Humans , Mice
15.
Curr Issues Mol Biol ; 43(1): 389-404, 2021 Jun 19.
Article in English | MEDLINE | ID: mdl-34205365

ABSTRACT

Fabry disease is an X-linked disorder of α-galactosidase A (GLA) deficiency. Our previous interim analysis (1 July 2014 to 31 December 2015) revealed plasma globotriaosylsphingosine as a promising primary screening biomarker for Fabry disease probands. Herein, we report the final results, including patients enrolled from 1 January to 31 December 2016 for evaluating the potential of plasma globotriaosylsphingosine and GLA activity as a combined screening marker. We screened 5691 patients (3439 males) referred from 237 Japanese specialty clinics based on clinical findings suggestive of Fabry disease using plasma globotriaosylsphingosine and GLA activity as primary screening markers, and GLA variant status as a secondary screening marker. Of the 14 males who tested positive in the globotriaosylsphingosine screen (≥2.0 ng/mL), 11 with low GLA activity (<4.0 nmol/h/mL) displayed GLA variants (four classic, seven late-onset) and one with normal GLA activity and no pathogenic variant displayed lamellar bodies in affected organs, indicating late-onset biopsy-proven Fabry disease. Of the 19 females who tested positive in the globotriaosylsphingosine screen, eight with low GLA activity displayed GLA variants (six classic, two late-onset) and five with normal GLA activity displayed a GLA variant (one classic) and no pathogenic variant (four late-onset biopsy-proven). The combination of plasma globotriaosylsphingosine and GLA activity can be a primary screening biomarker for classic, late-onset, and late-onset biopsy-proven Fabry disease probands.


Subject(s)
Biomarkers/blood , Fabry Disease/blood , Glycolipids/blood , Mass Screening/methods , Sphingolipids/blood , alpha-Galactosidase/blood , Adolescent , Adult , Aged , Asian People , Child , Cohort Studies , Fabry Disease/diagnosis , Fabry Disease/ethnology , Female , Humans , Japan , Male , Middle Aged , Sensitivity and Specificity , alpha-Galactosidase/metabolism
16.
Diabetes Ther ; 12(3): 655-667, 2021 Mar.
Article in English | MEDLINE | ID: mdl-33474645

ABSTRACT

INTRODUCTION: Dipeptidyl peptidase 4 (DPP4) inhibitors are widely used in patients with type 2 diabetes mellitus (T2DM) on maintenance hemodialysis (HD), but the efficacy of the once-weekly DPP4 inhibitor omarigliptin is not known. METHODS: This prospective, randomized, open-label, parallel-group, non-inferiority/superiority, once-daily DPP4 inhibitor linagliptin-controlled, multicenter study examined glycemic control and safety of omarigliptin (UMIN000024284). Sample size was calculated to confirm non-inferiority in terms of changes in glycated hemoglobin (HbA1c). We enrolled 33 patients with T2DM on maintenance HD who had been treated with linagliptin for at least 3 months. The patients were randomized to receive omarigliptin (12.5 mg/week; n = 16) or linagliptin (5 mg/day; n = 17). Primary endpoints were changes in HbA1c and glycoalbumin (GA) over 24 weeks. RESULTS: Differences in the mean change in primary endpoint values between the omarigliptin and linagliptin groups were - 0.61% [- 1.14, - 0.09] for HbA1c, with a two-tailed upper 95% limit (i.e., one-tailed 97.5% upper limit) of 0.25%, below the non-inferiority limit, and - 1.67% [- 4.23, + 0.88] for GA, with a two-tailed upper 95% limit of 0.75%, above the non-inferiority limit. At 24 weeks, the omarigliptin group showed significantly greater reduction in HbA1c than the linagliptin group (- 0.2% ± 0.6% vs. 0.4% ± 0.8%, two-tailed p = 0.024) and significantly greater reduction in blood glucose after a single HD session (- 18.4 ± 31.4 mg/dL vs. 25.2 ± 59.5 mg/dL, respectively, two-tailed p = 0.019). No subjects in the omarigliptin group developed hypoglycemia. CONCLUSIONS: Our data showed that omarigliptin was non-inferior to linagliptin in glycemic control. Omarigliptin is feasible for glycemic control in patients with T2DM on maintenance HD. CLINICAL TRIALS REGISTRATION: UMIN000024284.

17.
Sci Rep ; 11(1): 750, 2021 01 12.
Article in English | MEDLINE | ID: mdl-33437029

ABSTRACT

Cisplatin, one of the most active anticancer agents, is widely used in standard chemotherapy for various cancers. Cisplatin is more poorly tolerated than other chemotherapeutic drugs, and the main dose-limiting toxicity of cisplatin is its nephrotoxicity, which is dose-dependent. Although less toxic methods of cisplatin administration have been established, cisplatin-induced nephrotoxicity remains an unsolved problem. Megalin is an endocytic receptor expressed at the apical membrane of proximal tubules. We previously demonstrated that nephrotoxic drugs, including cisplatin, are reabsorbed through megalin and cause proximal tubular cell injury. We further found that cilastatin blocked the binding of cisplatin to megalin in vitro. In this study, we investigated whether cilastatin could reduce cisplatin-induced nephrotoxicity without influencing the antitumor effects of cisplatin. Nephrotoxicity was decreased or absent in mice treated with cisplatin and cilastatin, as determined by kidney injury molecule-1 staining and the blood urea nitrogen content. Combined with cilastatin, a twofold dose of cisplatin was used to successfully treat the mice, which enhanced the antitumor effects of cisplatin but reduced its nephrotoxicity. These findings suggest that we can increase the dose of cisplatin when combined with cilastatin and improve the outcome of cancer patients.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/pharmacology , Colonic Neoplasms/drug therapy , Renal Insufficiency/prevention & control , Animals , Apoptosis , Cell Proliferation , Cilastatin/administration & dosage , Cisplatin/administration & dosage , Colonic Neoplasms/metabolism , Colonic Neoplasms/pathology , Female , Glomerular Filtration Rate , Humans , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Inbred ICR , Mice, Inbred NOD , Mice, SCID , Tumor Cells, Cultured , Xenograft Model Antitumor Assays
18.
Diabetes Ther ; 11(12): 2845-2861, 2020 Dec.
Article in English | MEDLINE | ID: mdl-33000383

ABSTRACT

INTRODUCTION: The precise blood glucose (BG) profile of hemodialysis patients is unclear, as is the effectiveness of dipeptidyl peptidase-4 (DPP-4) inhibitors in hemodialysis patients with type 2 diabetes. Here, we used continuous glucose monitoring (CGM) to evaluate BG variability in these patients and to assess the efficacy of DPP-4 inhibitors, particularly during hemodialysis sessions and at nighttime (UMIN000012638). METHODS: We examined BG profiles using CGM in 31 maintenance hemodialysis patients with type 2 diabetes. Differences between patients with and without DPP-4 inhibitors (n = 15 and 16, respectively) were analyzed using a linear mixed-effects model to assess changes in glucose levels in 5-min intervals. RESULTS: The model revealed that DPP-4 inhibitor use was significantly associated with suppression of a rapid drop in glucose levels, both with and without adjustment for BG levels at the start of hemodialysis. Moreover, the model revealed that the two groups differed significantly in the pattern of changes in BG levels from 0:00 to 6:55 am. DPP-4 inhibitors suppressed the tendency for subsequent nocturnal hypoglycemia. CONCLUSIONS: This prospective observational exploratory study showed that DPP-4 inhibitors could suppress BG variability during hemodialysis sessions as well as subsequent nocturnal changes in patients with type 2 diabetes. TRIAL REGISTRATION: ClinicalTrials.gov identifier, UMIN000012638.

19.
Nutrients ; 11(12)2019 Dec 02.
Article in English | MEDLINE | ID: mdl-31810329

ABSTRACT

Obesity and related disorders, which are increasing in adults worldwide, are closely linked to childhood diet and are associated with chronic inflammation. Rice endosperm protein (REP) intake during adulthood has been reported to improve lipid metabolism and suppress the progression of diabetic kidney disease in animal models. However, the effects of REP intake during childhood on adulthood health are unclear. Therefore, we used a mouse model to experimentally investigate the preconditioning effects of REP intake during childhood on the development of obesity and related disorders in adulthood. Male C57BL/6J mice were pair-fed a normal-fat diet containing casein or REP during the juvenile period and then a high-fat diet (HFD) containing casein or REP during adulthood. Mice fed REP during the juvenile period showed better body weight, blood pressure, serum lipid profiles, lipopolysaccharide (LPS)-binding protein levels, and glucose tolerance in adulthood than those fed casein during the juvenile period. HFD-induced renal tubulo-glomerular alterations and hepatic microvesicular steatosis were less evident in REP-fed mice than in casein-fed ones. REP intake during the juvenile period improved HFD-induced dysbiosis (i.e., Escherichia genus proliferation and reduced gut microbiota diversity), thereby suppressing endotoxin-related chronic inflammation. Indeed, REP-derived peptides showed antibacterial activity against Escherichia coli, a major producer of LPS. In conclusion, REP supplementation during the juvenile period may regulate the gut microbiota and thus suppress the development of obesity and related disorders in adulthood in mice.


Subject(s)
Endosperm , Gastrointestinal Microbiome/drug effects , Obesity/prevention & control , Oryza , Plant Proteins/administration & dosage , Animals , Diet, High-Fat/adverse effects , Disease Models, Animal , Dysbiosis/etiology , Dysbiosis/therapy , Male , Mice , Mice, Inbred C57BL , Obesity/etiology , Obesity/microbiology
20.
BMC Cancer ; 19(1): 1170, 2019 Dec 02.
Article in English | MEDLINE | ID: mdl-31791266

ABSTRACT

BACKGROUND: Cisplatin is a potent chemotherapeutic agent used to treat a variety of solid tumors. One of the major side effects of cisplatin is dose-limiting nephrotoxicity. We recently demonstrated that the renal uptake of cisplatin and resultant cisplatin-induced nephrotoxicity are mediated in part by megalin, an endocytic receptor in proximal tubule epithelial cells (PTECs). We also developed sandwich enzyme-linked immunosorbent assays to measure the megalin ectodomain (A-megalin) and full-length megalin (C-megalin) in urine using monoclonal antibodies against the amino- and carboxyl-termini of megalin, respectively. The present study examined the correlation of urinary megalin level with cisplatin-induced nephrotoxicity and its utility as a biomarker in patients with thoracic cancer. METHODS: This prospective observational study involved 45 chemotherapy-naïve patients scheduled to receive chemotherapy with ≥60 mg/m2 cisplatin for histologically diagnosed small cell lung cancer, non-small cell lung cancer, or malignant pleural mesothelioma. Before and after the first course of chemotherapy, we measured urinary A- and C-megalin and other markers of PTEC injury, such as N-acetyl-ß-D-glucosaminidase, α1-microglobulin, ß2-microglobulin, neutrophil gelatinase-associated lipocalin, and liver-type fatty acid-binding protein, and compared the values with the change in the estimated glomerular filtration rate (eGFR) and clinical risk factors for renal impairment. RESULTS: A negative correlation was found between baseline urinary A-megalin levels and change in eGFR (r = - 0.458, P = 0.002). According to Kaplan-Meier survival curves, eGFR decline was associated with the baseline urinary A-megalin quartile (P = 0.038). In addition, according to the hazard ratios (HRs) for eGFR decline > 10 mL/min/1.73 m2 calculated using a Cox proportional hazard model, the highest quartile had a significantly higher risk of eGFR decline compared with the lowest quartile (HR 7.243; 95% confidence interval 1.545-33.962). Other baseline urinary markers showed no correlation with eGFR decline. CONCLUSIONS: This is the first report demonstrating that prechemotherapy urinary A-megalin levels are correlated with the development of cisplatin-induced nephrotoxicity. This finding has clinical implications for the identification of patients at risk for cisplatin-induced nephrotoxicity and the development of possible prophylactic therapies.


Subject(s)
Acute Kidney Injury/chemically induced , Acute Kidney Injury/urine , Antineoplastic Agents/adverse effects , Cisplatin/adverse effects , Low Density Lipoprotein Receptor-Related Protein-2/metabolism , Acute Kidney Injury/pathology , Acute Kidney Injury/physiopathology , Aged , Biomarkers/metabolism , Biomarkers/urine , Enzyme-Linked Immunosorbent Assay , Female , Glomerular Filtration Rate , Humans , Kaplan-Meier Estimate , Kidney Tubules, Proximal/metabolism , Kidney Tubules, Proximal/pathology , Kidney Tubules, Proximal/physiopathology , Male , Middle Aged , Prospective Studies , Thoracic Neoplasms/drug therapy , Thoracic Neoplasms/pathology , Thoracic Neoplasms/urine
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