Qianjin Wenwu decoction suppresses renal interstitial fibrosis by enhancing the degradation of extracellular matrix in mice with unilateral ureteral obstruction / 中国天然药物

Diabetic kidney disease (DKD) is the most common complication of diabetes mellitus (DM). Qianjin Wenwu decoction (QWD), a well-known traditional Korean medicine, has been used for the treatment of DKD, with satisfactory therapeutic effects. This study was designed to investigate the active components and mechanisms of action of QWD in the treatment of DKD. The results demonstrated that a total of 13 active components in five types were found in QWD, including flavonoids, flavonoid glycosides, phenylpropionic acids, saponins, coumarins, and lignins. Two key proteins, TGF-β1 and TIMP-1, were identified as the target proteins through molecular docking. Furthermore, QWD significantly suppressed Scr and BUN levels which increased after unilateral ureteral obstruction (UUO). Hematoxylin & eosin (H&E) and Masson staining results demonstrated that QWD significantly alleviated renal interstitial fibrosis in UUO mice. We also found that QWD promoted ECM degradation by regulating MMP-9/TIMP-1 homeostasis to improve renal tubulointerstitial fibrosis and interfere with the expression and activity of TGF- β1 in DKD treatment. These findings explain the underlying mechanism of QWD for the treatment of DKD, and also provide methodological reference for investigating the mechanism of traditional medicine in the treatment of DKD.

Correlation between urine vitamin D -binding protein and early -stage renal damage in Type 2 diabetes / 中南大学学报(医学版)

OBJECTIVES@#The excretion of urinary vitamin D-binding protein (uVDBP) is related to the occurrence and development of early-stage renal damage in patients with Type 2 diabetes (T2DM). This study aims to explore the significance of detecting uVDBP in T2DM patients and its relationship with renal tubules, and to provide a new direction for the early diagnosis of T2DM renal damage.@*METHODS@#A total of 105 patients with T2DM, who met the inclusion criteria, were included as a patient group, and recruited 30 individuals as a normal control group. The general information and blood and urine biochemical indicators of all subjects were collected; the levels of uVDBP, and a marker of tubular injury [urine kidney injury molecule 1 (uKIM-1), urine neutrophil gelatinase-associated lipocalin (uNGAL) and urine retinol-binding protein (uRBP)] were detected by enzyme-linked immunosorbent assay. The results were corrected by urinary creatinine (Cr) to uVDBP/Cr, uKIM-1/Cr, uNGAL/Cr and uRBP/Cr. The Pearson's and Spearman's correlation tests were used to analyze the correlation between uVDBP/Cr and urine albumin-to-creatinine ratio (UACR), estimated glomerular filtration rate (eGFR) and markers of tubular injury, and multivariate linear regression and receiver operating characteristic curve were used to analyze the correlation between uVDBP/Cr and UACR or eGFR.@*RESULTS@#Compared with the normal control group, the uVDBP/Cr level in the patient group was increased (P<0.05), and which was positively correlated with UACR (r=0.774, P<0.01), and negatively correlated with eGFR (r=-0.397, P<0.01). There were differences in the levels of uKIM-1/Cr, uNGAL/Cr, and uRBP/Cr between the 2 groups (all P<0.01). The uVDBP/Cr was positively correlated with uKIM-1/Cr (r=0.752, P<0.01), uNGAL/Cr (r=0.644, P<0.01) and uRBP/Cr (r=0.812, P<0.01). The sensitivity was 90.0% and the specificity was 82.9% (UACR>30 mg/g) for evaluation of uVDBP/Cr on T2DM patients with early-stage renal damage, while the sensitivity was 75.0% and the specificity was 72.6% for evaluation of eGFR on T2DM patients with early-stage renal damage.@*CONCLUSIONS@#The uVDBP/Cr can be used as a biomarker in early-stage renal damage in T2DM patients.

Inositol 1,4,5-triphosphate receptor 3 promotes renal cyst development in autosomal dominant polycystic kidney disease / 生理学报

The purpose of the present study was to determine the role of inositol 1,4,5-trisphosphate receptor 3 (IP3R3) in renal cyst development in autosomal dominant polycystic kidney disease (ADPKD). 2-aminoethoxy-diphenyl borate (2-APB) and shRNA were used to suppress the expression of IP3R3. The effect of IP3R3 on cyst growth was investigated in Madin-Darby canine kidney (MDCK) cyst model, embryonic kidney cyst model and kidney specific Pkd1 knockout (PKD) mouse model. The underlying mechanism of IP3R3 in promoting renal cyst development was investigated by Western blot and immunofluorescence staining. The results showed that the expression level of IP3R3 was significantly increased in the kidneys of PKD mice. Inhibiting IP3R3 by 2-APB or shRNA significantly retarded cyst expansion in MDCK cyst model and embryonic kidney cyst model. Western blot and immunofluorescence staining results showed that hyperactivated cAMP-PKA signaling pathway in the growth process of ADPKD cyst promoted the expression of IP3R3, which was accompanied by a subcellular redistribution process in which IP3R3 was translocated from endoplasmic reticulum to intercellular junction. The abnormal expression and subcellular localization of IP3R3 further promoted cyst epithelial cell proliferation by activating MAPK and mTOR signaling pathways and accelerating cell cycle. These results suggest that the expression and subcellular distribution of IP3R3 are involved in promoting renal cyst development, which implies IP3R3 as a potential therapeutic target of ADPKD.

Regulation of kidney on potassium balance and its clinical significance / 生理学报

Virtually all of the dietary potassium intake is absorbed in the intestine, over 90% of which is excreted by the kidneys regarded as the most important organ of potassium excretion in the body. The renal excretion of potassium results primarily from the secretion of potassium by the principal cells in the aldosterone-sensitive distal nephron (ASDN), which is coupled to the reabsorption of Na+ by the epithelial Na+ channel (ENaC) located at the apical membrane of principal cells. When Na+ is transferred from the lumen into the cell by ENaC, the negativity in the lumen is relatively increased. K+ efflux, H+ efflux, and Cl- influx are the 3 pathways that respond to Na+ influx, that is, all these 3 pathways are coupled to Na+ influx. In general, Na+ influx is equal to the sum of K+ efflux, H+ efflux, and Cl- influx. Therefore, any alteration in Na+ influx, H+ efflux, or Cl- influx can affect K+ efflux, thereby affecting the renal K+ excretion. Firstly, Na+ influx is affected by the expression level of ENaC, which is mainly regulated by the aldosterone-mineralocorticoid receptor (MR) pathway. ENaC gain-of-function mutations (Liddle syndrome, also known as pseudohyperaldosteronism), MR gain-of-function mutations (Geller syndrome), increased aldosterone levels (primary/secondary hyperaldosteronism), and increased cortisol (Cushing syndrome) or deoxycorticosterone (hypercortisolism) which also activate MR, can lead to up-regulation of ENaC expression, and increased Na+ reabsorption, K+ excretion, as well as H+ excretion, clinically manifested as hypertension, hypokalemia and alkalosis. Conversely, ENaC inactivating mutations (pseudohypoaldosteronism type 1b), MR inactivating mutations (pseudohypoaldosteronism type 1a), or decreased aldosterone levels (hypoaldosteronism) can cause decreased reabsorption of Na+ and decreased excretion of both K+ and H+, clinically manifested as hypotension, hyperkalemia, and acidosis. The ENaC inhibitors amiloride and Triamterene can cause manifestations resembling pseudohypoaldosteronism type 1b; MR antagonist spironolactone causes manifestations similar to pseudohypoaldosteronism type 1a. Secondly, Na+ influx is regulated by the distal delivery of water and sodium. Therefore, when loss-of-function mutations in Na+-K+-2Cl- cotransporter (NKCC) expressed in the thick ascending limb of the loop and in Na+-Cl- cotransporter (NCC) expressed in the distal convoluted tubule (Bartter syndrome and Gitelman syndrome, respectively) occur, the distal delivery of water and sodium increases, followed by an increase in the reabsorption of Na+ by ENaC at the collecting duct, as well as increased excretion of K+ and H+, clinically manifested as hypokalemia and alkalosis. Loop diuretics acting as NKCC inhibitors and thiazide diuretics acting as NCC inhibitors can cause manifestations resembling Bartter syndrome and Gitelman syndrome, respectively. Conversely, when the distal delivery of water and sodium is reduced (e.g., Gordon syndrome, also known as pseudohypoaldosteronism type 2), it is manifested as hypertension, hyperkalemia, and acidosis. Finally, when the distal delivery of non-chloride anions increases (e.g., proximal renal tubular acidosis and congenital chloride-losing diarrhea), the influx of Cl- in the collecting duct decreases; or when the excretion of hydrogen ions by collecting duct intercalated cells is impaired (e.g., distal renal tubular acidosis), the efflux of H+ decreases. Both above conditions can lead to increased K+ secretion and hypokalemia. In this review, we focus on the regulatory mechanisms of renal potassium excretion and the corresponding diseases arising from dysregulation.

Single-cell RNA sequencing reveals the transcriptomic landscape of kidneys in patients with ischemic acute kidney injury / 中华医学杂志(英文版)

BACKGROUND@#Ischemic acute kidney injury (AKI) is a common syndrome associated with considerable mortality and healthcare costs. Up to now, the underlying pathogenesis of ischemic AKI remains incompletely understood, and specific strategies for early diagnosis and treatment of ischemic AKI are still lacking. Here, this study aimed to define the transcriptomic landscape of AKI patients through single-cell RNA sequencing (scRNA-seq) analysis in kidneys.@*METHODS@#In this study, scRNA-seq technology was applied to kidneys from two ischemic AKI patients, and three human public scRNA-seq datasets were collected as controls. Differentially expressed genes (DEGs) and cell clusters of kidneys were determined. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, as well as the ligand-receptor interaction between cells, were performed. We also validated several DEGs expression in kidneys from human ischemic AKI and ischemia/reperfusion (I/R) injury induced AKI mice through immunohistochemistry staining.@*RESULTS@#15 distinct cell clusters were determined in kidney from subjects of ischemic AKI and control. The injured proximal tubules (PT) displayed a proapoptotic and proinflammatory phenotype. PT cells of ischemic AKI had up-regulation of novel pro-apoptotic genes including USP47 , RASSF4 , EBAG9 , IER3 , SASH1 , SEPTIN7 , and NUB1 , which have not been reported in ischemic AKI previously. Several hub genes were validated in kidneys from human AKI and renal I/R injury mice, respectively. Furthermore, PT highly expressed DEGs enriched in endoplasmic reticulum stress, autophagy, and retinoic acid-inducible gene I (RIG-I) signaling. DEGs overexpressed in other tubular cells were primarily enriched in nucleotide-binding and oligomerization domain (NOD)-like receptor signaling, estrogen signaling, interleukin (IL)-12 signaling, and IL-17 signaling. Overexpressed genes in kidney-resident immune cells including macrophages, natural killer T (NKT) cells, monocytes, and dendritic cells were associated with leukocyte activation, chemotaxis, cell adhesion, and complement activation. In addition, the ligand-receptor interactions analysis revealed prominent communications between macrophages and monocytes with other cells in the process of ischemic AKI.@*CONCLUSION@#Together, this study reveals distinct cell-specific transcriptomic atlas of kidney in ischemic AKI patients, altered signaling pathways, and potential cell-cell crosstalk in the development of AKI. These data reveal new insights into the pathogenesis and potential therapeutic strategies in ischemic AKI.

The role of regulated cell death in renal ischemia-reperfusion injury / 生理学报

Renal ischemia-reperfusion injury (IRI) is histologically characterized by tubular cell death. Diverse pathways of regulated cell death (RCD) have been reported to contribute to renal IRI in recent studies. In this review, we discuss the signaling pathways, regulators and crosstalk of RCD, including necroptosis, ferroptosis and pyroptosis, and their role in renal IRI in order to pave the way for new therapeutic opportunities.

The mechanism of blood pressure regulation by high potassium diet in the kidney / 生理学报

Hypertension is one of the strongest risk factors for cardiovascular diseases, cerebral stroke, and kidney failure. Lifestyle and nutrition are important factors that modulate blood pressure. Hypertension can be controlled by increasing physical activity, decreasing alcohol and sodium intake, and stopping tobacco smoking. Chronic kidney disease patients often have increased blood pressure, which indicates that kidney is one of the major organs responsible for blood pressure homeostasis. The decrease of renal sodium reabsorption and increase of diuresis induced by high potassium intake is critical for the blood pressure reduction. The beneficial effect of a high potassium diet on hypertension could be explained by decreased salt reabsorption by sodium-chloride cotransporter (NCC) in the distal convoluted tubule (DCT). In DCT cells, NCC activity is controlled by with-no-lysine kinases (WNKs) and its down-stream target kinases, Ste20-related proline-alanine-rich kinase (SPAK) and oxidative stress-responsive 1 (OSR1). The kinase activity of WNKs is inhibited by intracellular chloride ([Cl-]i) and WNK4 is known to be the major WNK positively regulating NCC. Based on our previous studies, high potassium intake reduces the basolateral potassium conductance, decreases the negativity of DCT basolateral membrane (depolarization), and increases [Cl-]i. High [Cl-]i inhibits WNK4-SPAK/OSR1 pathway, and thereby decreases NCC phosphorylation. In this review, we discuss the role of DCT in the blood pressure regulation by dietary potassium intake, which is the mechanism that has been best dissected so far.

Research progress of vascular endothelial growth factor-A and its isoforms in kidney disease / 生理学报

Vascular endothelial growth factor-A (VEGF-A) is a critical angiogenic factor which is mainly secreted from podocytes and epithelial cells in kidney and plays an important role in renal pathophysiology. In recent years, functions of different isoforms of VEGF-A and the new secretion approach via extracellular vesicles (EVs) have been identified. Thus, further understanding are needed for the role of VEGF-A and its isoforms in renal injury and repair. In this review, we summarized the expression, secretion and regulation of VEGF-A, its biological function, and the role of different isoforms of VEGF-A in the development of different renal diseases. Meanwhile, the research progress of VEGF-A as diagnostic marker and therapeutic target for renal diseases were discussed.

The renal metabolic mechanism of salt sensitive hypertension in Dahl-SS rats / 生理学报

The kidney is one of the main target organs involved in hypertension, and it regulates water and salt metabolism, blood volume and vascular resistance. High salt intake induces salt and water retention, persistent endothelial dysfunction and elevation of blood pressure in salt sensitive individuals. Dahl salt sensitive (Dahl-SS) rats, as a classic animal model for salt sensitive hypertension, have many similar stably inherited physiological characteristics to human with salt sensitive hypertension, such as salt sensitivity, hyperlipidemia, insulin resistance, renal failure, increased urinary protein secretion and low plasma renin activity. Based on renal physiology and biochemistry researches and multi-omics analyses in Dahl-SS rats, this review will summarize the relationship between salt sensitive hypertension and renal redox, NO, amino acids, glucose and lipid metabolism.

Wnt/β-catenin signaling in kidney repair and fibrosis after injury / 生理学报

Wnt/β-catenin is an evolutionarily conserved, complex developmental signal pathway that regulates embryogenesis, cell fate, tissue homeostasis, injury repair, and the pathogenesis of human diseases. Mounting evidence demonstrates that Wnt/β-catenin signaling plays a key role in early nephrogenesis. It is relatively silent in normal adult kidneys but reactivated in a wide variety of animal models of nephropathies and in human kidney diseases. Activation of Wnt/β-catenin after acute kidney injury contributes to proper repair and regeneration of damaged renal tubules. However, sustained activation of this signal cascade is closely related to the development and progression of fibrotic chronic kidney disease. In this paper, we systematically review the components and mechanisms of Wnt/β-catenin signaling and its role in kidney repair and fibrosis after injury. A better delineation of the mechanisms of this pathway will provide novel targets and new strategies for designing effective treatment of various kidney diseases.

Acute kidney injury and regulated cell death / 生理学报

Acute kidney injury (AKI) refers to a clinical syndrome in which renal function declines rapidly in a short period of time caused by various pathological factors. During the development of AKI, renal tubules with the functions of reabsorption and excretion are prone to cell death due to external pathological stimuli, which is an important cause of impaired renal function. In recent years, a variety of new cell death pathways have been gradually recognized. Researchers have now found that regulated cell death (RCD), such as necroptosis, pyroptosis and ferroptosis, are important regulatory mechanisms of AKI. This article will summarize the research advances of various types of RCD involved in the process of AKI, aiming to deepen the understanding of AKI and provide innovative thoughts for the clinical treatment of AKI.

The distribution and function of aquaporin 1 and 2 along the kidney in different species / Distribución y función de la acuaporina 1 y 2 a lo largo del riñón en diferentes especies

SUMMARY: Water metabolism in kidney is critical for organisms living in arid environments. In this study, the kidney structure and the expression of AQP1 and AQP2 in Phrynocephalus vlangalii and Camelus bactrianus were studied. It was found that the Phrynocephalus vlangalii has fewer renal corpuscle but developed kidney tubules, and AQP1 and AQP2 were mainly expressed in the kidney tubules. Camelus bactrianus has a large diameter of glomerulus, thick bulbar membrane, and long and dense urinary tract. AQP1 was highly expressed in the proximal convoluted tubule, proximal straight tubule, and Ansa nephroni (Henle´s loop), and AQP2 was also highly expressed in the collecting tubule and distal convoluted tubule. In the long-term evolutionary adaptation, the morphological structure of animal kidney is consistent with its environment. In addition to structural and functional adaptation, aquaporin also participates in the adaptation to water scarcity environment, and may also play a key role.

RESUMEN: El metabolismo del agua en los riñones es fundamental para los organismos que viven en ambientes áridos. En este estudio, se estudió la estructura renal y la expresión de AQP1 y AQP2 en Phrynocephalus vlangalii y Camelus bactrianus. Se encontró que Phrynocephalus vlangalii tiene menos corpúsculos renales. pero desarrolló túbulos renales, y AQP1 y AQP2 se expresaron principalmente en los túbulos renales. Camelus bactrianus tiene un glomérulo de gran diámetro, una membrana bulbar gruesa y un tracto urinario largo y denso. AQP1 se expresó en gran medida en el túbulo contorneado proximal, el túbulo recto proximal y el Ansa nephroni o asa nefrónica (asa de Henle), y AQP2 también se expresó en gran medida en el túbulo colector y el túbulo contorneado distal. A largo plazo, en la adaptación evolutiva la estructura morfológica del riñón animal es coherente con su entorno. Además de la adaptación estructural y funcional, la acuaporina también es parte de la adaptación al entorno de escasez de agua y puede desempeñar un papel clave.

The protective effect of lycopene against oxidative kidney damage associated with combined use of isoniazid and rifampicin in rats

It is known that the combined use of antibiotics, such as isoniazid and rifampicin, in the treatment of tuberculosis causes oxidative kidney damage. The aim of this study was to biochemically and histopathologically investigate the effect of lycopene on oxidative kidney damage due to the administration of isoniazid and rifampicin in albino Wistar male rats. Lycopene at a dose of 5 mg/kg was orally administered to lycopene+isoniazid+rifampicin (LIR) rats, and normal sunflower oil (0.5 mL) was orally administered to isoniazid+rifampicin (IR) and healthy control (HG) rats as vehicle by gavage. One hour after the administration of lycopene and vehicle, 50 mg/kg isoniazid and rifampicin were given orally to the LIR and IR groups. This procedure was performed once a day for 28 days. Rats were sacrificed by a high dose of anesthesia at the end of this period, and oxidant-antioxidant parameters were measured in the removed kidney tissues. Creatinine and blood urea nitrogen (BUN) levels were measured in blood samples, and kidney tissues were also evaluated histopathologically. The combined administration of isoniazid and rifampicin changed the oxidant-antioxidant balance in favor of oxidants, and it increased blood urea nitrogen and creatinine levels, which are indicators of kidney function. Co-administration of isoniazid and rifampicin also caused oxidative kidney damage. Lycopene biochemically and histopathologically decreased oxidative kidney damage induced by isoniazid and rifampicin administration. These results suggested that lycopene may be beneficial in the treatment of nephrotoxicity due to isoniazid and rifampicin administration.

Huangkui capsule in combination with leflunomide improves immunoglobulin a nephropathy by inhibiting the TGF-ß1/Smad3 signaling pathway.

OBJECTIVES: To investigate the efficacy and potential molecular mechanism of Huangkui capsule in combination with leflunomide (HKL) for the treatment of immunoglobulin A nephropathy (IgAN) METHODS: IgAN rat models were constructed by treating rats with bovine serum albumin, lipopolysaccharide, and tetrachloromethane. Th22 cells were isolated from the blood samples of patients with IgAN using a CD4+ T cell isolation kit. The expression levels of the components of the TGF-β1/Smad3 signaling pathway, namely, TGF-β1, Smad2, Smad3, Smad4, and Smad7, were detected using quantitative reverse transcription polymerase chain reaction. Cell proliferation was determined using the MTT assay, cell viability was determined using the WST 1 method, and the chemotaxis of Th22 cells was observed using the wound healing assay. Changes in the histology of the kidney tissues were analyzed using hematoxylin and eosin staining. RESULTS: Compared with IgAN rats, the rats subjected to HKL treatment showed good improvement in kidney injuries, and the combined drug treatment performed much better than the single-drug treatment. In addition, following HKL treatment, the viability, proliferation, and chemotaxis of Th22 cells dramatically decreased (*p<0.05, **p<0.01, and ***p<0.001). In addition, CCL20, CCL22, and CCL27 levels decreased and the expression of the key components of the TGF-β1/Smad3 signaling pathway was downregulated in IgAN rats and Th22 cells (*p<0.05, ***p<0.001). CONCLUSIONS: By targeting the TGF-β1/Smad3 signaling pathway, HKL treatment can improve kidney injury in IgAN rats as well as the excessive proliferation and metastasis of Th22 cells.

The renoprotective effects of Heme Oxygenase-1 during contrast-induced acute kidney injury in preclinical diabetic models

OBJECTIVES: Contrast-induced acute kidney injury (CI-AKI) is an important clinical problem that can be aggravated by diabetes mellitus, a major risk factor. However, heme oxygenase-1 (HO-1), a promising therapeutic target, can exert antioxidant effects against CI-AKI. Thus, we investigated the role of HO-1 in CI-AKI in the presence of diabetes mellitus. METHODS: Twenty-eight male Wistar rats weighing 250-300g were subjected to left uninephrectomy, and concomitantly, diabetes induced by streptozotocin (65 mg/kg). After 12 weeks, iodinated contrast (meglumine ioxithalamate, 6 mL/kg) and hemin (HO-1 inducer-10 mg/k) were administered 60 min before iodinated contrast treatment. The rats were randomly divided into four groups: control, diabetes mellitus (DM), DM iodinated contrast (DMIC), and DMIC hemin (DMICH). Kidney function, albuminuria, oxidative profile, and histology were assessed. All experimental data were subjected to statistical analyses. RESULTS: CI-AKI in preclinical diabetic models decreased creatinine clearance and increased urinary neutrophil gelatinase-associated lipocalin (NGAL) levels and the degree of albuminuria. Additionally, the levels of oxidative and nitrosative stress metabolites (urinary peroxides, thiobarbituric acid-reactive substances, and NO) were elevated, while thiol levels in kidney tissue were reduced. Kidney histology showed tubular cell vacuolization and edema. HO-1 inducer treatment improved kidney function and reduced urinary the NGAL levels. The oxidative profile showed an increase in the endogenous thiol-based antioxidant levels. Additionally, the tubular injury score was reduced following HO-1 treatment. CONCLUSIONS: Our findings highlight the renoprotective effects of HO-1 in CI-AKI and preclinical diabetic models. Therefore, HO-1 ameliorates kidney dysfunction, reduces oxidative stress, and prevents cell necrosis.

Maternal hypothyroidism during pregnancy alters the function of the retinol-binding protein 4-mediated mitochondrial permeability conversion pore in the kidneys of offspring rats

OBJECTIVES To determine the role of the RBP4/PiC/SIRT3 signaling pathway in the opening of the mitochondria permeability transition pore (mPTP) in offspring rats with hypothyroidism during pregnancy. METHODS Sixty Sprague-Dawley (SD) rats were employed in this study. Pregnancy was deemed successful when a sperm was found in the uterus. After one week of pregnancy, offspring rats were divided into the following groups: overall hypothyroidism group (OH group), subclinical hypothyroidism group (SCH group), and normal control group (CON group). The establishment of the hypothyroidism model was confirmed when the serum thyroid stimulating hormone (TSH) levels were higher than normal value and TT4 level was within the normal range. The renal mitochondria of offspring rats were extracted on the 14th postnatal day (P14) and 35th postnatal day (P35). RESULTS At P14, no significant differences in the degree of mPTP opening and expression of phosphoric acid carrier vector (PiC) were detected between the rats in the OH group and the SCH group. However, the expression level of silent mating-type information regulation 3 homolog (SIRT3) was markedly reduced. Retinol-binding protein 4 (RBP4) expression increased in the rats from the OH group, relative to that in those from the SCH group. At P35, the degree of mPTP opening and the expression levels of PiC and RBP4 in the OH group were higher than those in the SCH group. However, SIRT3 expression in the OH group was lower than that observed in the SCH group. CONCLUSION RBP4 plays an important role in early renal mitochondrial damage and renal impairment in rats suffering from hypothyroidism during pregnancy. The RBP4/PiC/SIRT3 pathway is thus involved in the opening of the renal mPTP in offspring rats with hyperthyroidism.

Single-cell analysis of angiotensin-converting enzyme II expression in human kidneys and bladders reveals a potential route of 2019 novel coronavirus infection / 中华医学杂志(英文版)

BACKGROUND@#Since 2019, a novel coronavirus named 2019 novel coronavirus (2019-nCoV) has emerged worldwide. Apart from fever and respiratory complications, acute kidney injury has been observed in a few patients with coronavirus disease 2019. Furthermore, according to recent findings, the virus has been detected in urine. Angiotensin-converting enzyme II (ACE2) has been proposed to serve as the receptor for the entry of 2019-nCoV, which is the same as that for the severe acute respiratory syndrome. This study aimed to investigate the possible cause of kidney damage and the potential route of 2019-nCoV infection in the urinary system.@*METHODS@#We used both published kidney and bladder cell atlas data and new independent kidney single-cell RNA sequencing data generated in-house to evaluate ACE2 gene expression in all cell types in healthy kidneys and bladders. The Pearson correlation coefficients between ACE2 and all other genes were first generated. Then, genes with r values larger than 0.1 and P values smaller than 0.01 were deemed significant co-expression genes with ACE2.@*RESULTS@#Our results showed the enriched expression of ACE2 in all subtypes of proximal tubule (PT) cells of the kidney. ACE2 expression was found in 5.12%, 5.80%, and 14.38% of the proximal convoluted tubule cells, PT cells, and proximal straight tubule cells, respectively, in three published kidney cell atlas datasets. In addition, ACE2 expression was also confirmed in 12.05%, 6.80%, and 10.20% of cells of the proximal convoluted tubule, PT, and proximal straight tubule, respectively, in our own two healthy kidney samples. For the analysis of public data from three bladder samples, ACE2 expression was low but detectable in bladder epithelial cells. Only 0.25% and 1.28% of intermediate cells and umbrella cells, respectively, had ACE2 expression.@*CONCLUSION@#This study has provided bioinformatics evidence of the potential route of 2019-nCoV infection in the urinary system.

Las hormonas femeninas en fisiología renal: Sensibilidad a la sal y regulación de la proliferación epitelial / Female hormones in renal physiology. Salt sensitivity and regulation of epithelial proliferation

Un tercio de la población mundial tiene niveles anormalmente altos de presión arterial, hipertensión, responsable de casi el 50% de las muertes por accidente cerebrovascular y enfermedad coronaria. La sensibilidad a la sal es un factor de riesgo para la morbilidad y mortalidad cardiovascular y también para otras enfermedades. En estudios previos describimos un modelo de hipertensión sal sensible (HSS) en ratas Wistar ovariectomizadas (oVx) adultas. Las ratas oVx son normotensas con ingesta normal de sal (NS, 0.24% de NaCl), pero desarrollan un perfil de HSS con una ingesta elevada de sal (HS, 1% de NaCl). En los estudios en riñón encontramos que el circuito receptor D1 de dopamina, citocromo P450 4A y Na+, K+-ATPasa está alterado por la ausencia de hormonas ováricas, lo que se asocia a menor excreción de sodio e hipertensión arterial. La ingesta HS en ratas oVx también promueve cambios en la expresión de proteínas relacionadas con el transporte de sodio en células mononucleares de sangre periférica, principalmente linfocitos periféricos. Por lo tanto, el transporte de sodio se modifica en varios niveles de la fisiología normal. En estudios recientes observamos que el estradiol aumenta la proliferación y diferenciación de células epiteliales en cultivos de corteza renal humana. Sensibilidad a la sal, inmunidad adaptativa, presión arterial y proliferación de células epiteliales en riñón son fenómenos de gran importancia biológica regulados por estradiol.

Female sex hormones participate in the regulation of blood pressure and renal epithelial proliferation, effects not related to their reproductive function. About one-third of the world's population has abnormally high levels of blood pressure, hypertension, which is responsible for almost 50% of deaths from stroke and coronary heart disease. Salt sensitivity is a risk factor for cardiovascular morbidity and mortality and other diseases as well. We reported a model of salt sensitive hypertension in adult ovariectomized (oVx) Wistar rats. oVx rats are normotensive under normal salt intake (NS, 0.24% NaCl), but upon a high salt intake (HS, 1% NaCl) oVx rats developed a blood pressure profile of salt-sensitive hypertension. Our studies on kidney molecules related to sodium balance found that the circuit dopamine D1-like receptor, cytochrome P450 4A and Na+, K+-ATPase is altered by the absence of ovary hormones which is accompanied by a reduced ability to excrete sodium. In oVx rats HS intake also promotes changes in the expression of proteins related to sodium transport in peripheral blood mononuclear cells, mainly peripheral lymphocytes. Therefore, sodium transport is modified at several levels of normal physiology. Lately, we described that estradiol increases the rate of renal epithelial cell proliferation in primary cultures developed from human renal cortex. Thus, salt sensitivity, adaptive immunity, blood pressure and renal cell proliferation are complex biological responses regulated by female sex hormones.

SGLT-2 inhibitors in diabetes: a focus on renoprotection

SUMMARY Type 2 diabetes mellitus is an important public health problem, with a significant impact on cardiovascular morbidity and mortality and an important risk factor for chronic kidney disease. Various hypoglycemic therapies have proved to be beneficial to clinical outcomes, while others have failed to provide an improvement in cardiovascular and renal failure, only reducing blood glucose levels. Recently, sodium-glucose cotransporter-2 (SGLT2) inhibitors, represented by the empagliflozin, dapagliflozin, and canagliflozin, have been showing satisfactory and strong results in several clinical trials, especially regarding the reduction of cardiovascular mortality, reduction of hospitalization due to heart failure, reduction of albuminuria, and long-term maintenance of the glomerular filtration rate. The benefit from SGLT2 inhibitors stems from its main mechanism of action, which occurs in the proximal tubule of the nephron, causing glycosuria, and a consequent increase in natriuresis. This leads to increased sodium intake by the juxtaglomerular apparatus, activating the tubule glomerular-feedback and, finally, reducing intraglomerular hypertension, a frequent physiopathological condition in kidney disease caused by diabetes. In addition, this class of medication presents an appropriate safety profile, and its most frequently reported complication is an increase in the incidence of genital infections. Thus, these hypoglycemic agents gained space in practical recommendations for the management of type 2 diabetes mellitus and should be part of the initial therapeutic approach to provide, in addition to glycemic control, cardiovascular outcomes, and the renoprotection in the long term.