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Autopsy & Case Reports 2022Juxtaglomerular cell tumor is a benign, renin-secreting neoplasm. The tumor arises from the juxtaglomerular apparatus cells of the kidney. Because the tumor is...
Juxtaglomerular cell tumor is a benign, renin-secreting neoplasm. The tumor arises from the juxtaglomerular apparatus cells of the kidney. Because the tumor is hormonally active, patients usually suffer from hypokalemia, hyperaldosteronism, and hypertension. Herein, we describe a case of a 19-year-old Asian female with a somewhat unusual presentation. A 19-year-old Asian female presented with upper extremity weakness, numbness, and tingling. On physical examination, the only notable finding was hypertension. Extensive workup revealed elevated aldosterone level and plasma renin activity. CT scan of the abdomen revealed a 2.2 cm mass in the lower pole of the left kidney. The mass was resected by partial nephrectomy. On microscopic evaluation, the tumor had glomoid appearance with sheets of uniform, round to polygonal cells with clear to eosinophilic cytoplasm. Immunohistochemical stains showed the tumor cells to be positive for CD117, CD34 and CD10 and negative for ER, PR, CK7, PAX-8, pan-cytokeratin, EMA, S100, Melan-A, HMB45, SMA and CAIX. Diagnosis of Juxtaglomerular cell tumor was rendered. This case highlights the importance of a regular physical exam and a high index of suspicion in patients presenting with unusual complaints.
PubMed: 36312876
DOI: 10.4322/acr.2021.406 -
American Journal of Physiology. Renal... Dec 2021Macula densa (MD) cells, a chief sensory cell type in the nephron, are endowed with unique microanatomic features including a high density of protein synthetic...
Macula densa (MD) cells, a chief sensory cell type in the nephron, are endowed with unique microanatomic features including a high density of protein synthetic organelles and secretory vesicles in basal cell processes ("maculapodia") that suggest a so far unknown high rate of MD protein synthesis. This study aimed to explore the rate and regulation of MD protein synthesis and their effects on glomerular function using novel transgenic mouse models, newly established fluorescence cell biology techniques, and intravital microscopy. Sox2-tdTomato kidney tissue sections and an -propargyl puromycin incorporation-based fluorescence imaging assay showed that MD cells have the highest level of protein synthesis within the kidney cortex followed by intercalated cells and podocytes. Genetic gain of function of mammalian target of rapamycin (mTOR) signaling specifically in MD cells (in MD-mTOR mice) or their physiological activation by low-salt diet resulted in further significant increases in the synthesis of MD proteins. Specifically, these included both classic and recently identified MD-specific proteins such as cyclooxygenase 2, microsomal prostaglandin E synthase 1, and pappalysin 2. Intravital imaging of the kidney using multiphoton microscopy showed significant increases in afferent and efferent arteriole and glomerular capillary diameters and blood flow in MD-mTOR mice coupled with an elevated glomerular filtration rate. The presently identified high rate of MD protein synthesis that is regulated by mTOR signaling is a novel component of the physiological activation and glomerular hemodynamic regulatory functions of MD cells that remains to be fully characterized. This study discovered the high rate of protein synthesis in macula densa (MD) cells by applying direct imaging techniques with single cell resolution. Physiological activation and mammalian target of rapamycin signaling played important regulatory roles in this process. This new feature is a novel component of the tubuloglomerular cross talk and glomerular hemodynamic regulatory functions of MD cells. Future work is needed to elucidate the nature and (patho)physiological role of the specific proteins synthesized by MD cells.
Topics: Animals; Autocrine Communication; Diet, Sodium-Restricted; Glomerular Filtration Rate; Green Fluorescent Proteins; Humans; Intravital Microscopy; Juxtaglomerular Apparatus; Luminescent Proteins; Mice, Inbred C57BL; Mice, Transgenic; Microscopy, Fluorescence, Multiphoton; Nitric Oxide Synthase Type I; Paracrine Communication; Protein Biosynthesis; Renin; Signal Transduction; Sodium, Dietary; TOR Serine-Threonine Kinases; Tuberous Sclerosis Complex 2 Protein; Red Fluorescent Protein; Mice
PubMed: 34693742
DOI: 10.1152/ajprenal.00222.2021 -
Annals of Plastic Surgery Dec 2022This study evaluated the potential of Wharton's jelly mesenchymal stem cells with high tolerogenic properties in reducing immunosuppressive dosage and related adverse...
BACKGROUND
This study evaluated the potential of Wharton's jelly mesenchymal stem cells with high tolerogenic properties in reducing immunosuppressive dosage and related adverse effects.
METHODS
A 4- to 6-week-old, 30-40 g weight, male inbred CD57BL/6 mice were used as skin allograft donors, whereas Balb/c mice with similar characteristics were used as recipients. Wharton's jelly stem cells were obtained from a commercial kit sourced from human umbilical cord. Skin allografts were performed from CD57Bl6 to Balb/c mice (day 0). Group 1 (control) received no treatment. Group 2 received 15 mg/kg cyclosporin A on days 0 to 30. Group 3 received 5.7 × 10 6 and 10.3 × 10 6 cell/kg Wharton's jelly stem cells on days 0 and 3, respectively. Groups 4, 5, and 6 received a combination of 15, 10, and 5 mg/kg per day cyclosporine A (days 0 to 30) with the same stem cell dose with group 3, respectively. Graft rejection was evaluated with digital photography and thermal imaging, histopathology (Banff grading, epithelialization scores, dermoepidermal dissociation), immunochemistry (Ki-67 and Bcl-2), and biochemical methods (interleukin 10, interleukin 2, interferon γ, tumor necrosis factor α) (day 10). Cumulative adverse effects of cyclosporin A occurring in the groups were revealed by histopathological evaluation of kidney and liver (a modified semiquantitative method of infiltration of inflammatory cells around the portal area and lobular region in liver; modification of the Banff rating of proximal tubules and hypertrophia of juxtaglomerular apparatus cells in kidney) (day 30).
RESULTS
There was no rejection in groups 2, 4, and 5 until the end of study. These were statistically different versus groups 1 (day 10 ± 0.71), 3 (day 11 ± 0.82), and 6 (day 11 ± 0.58) (all P 's < 0.05). Groups 4 and 5 have exhibited statistically similar findings in histopathological (4 epithelization score: 3.7 ± 1.3; 5 epithelization score: 3.5 ± 0.5; 4 Banff grading score: 0.8 ± 0.6; 5 Banff grading score: 1.0 ± 0.5; both P 's = 1.00), immunohistochemical (4 Bcl-2 score: 3.5 ± 0.5, P = 0.618; 5 Bcl-2 score: 3.4 ± 0.5, P = 1.00; 4 Ki-67 score: 3.7 ± 0.4, P = 1.00; 5 Ki-67 score: 3.5 ± 0.5, both P 's = 1.00), and levels of cytokines (both P 's = 1.00) versus group 2. Adverse effects on kidneys and liver were lowest and statistically similar in groups 3, 5, and 6 (all P 's = 00) versus group 1.
CONCLUSIONS
Wharton's jelly mesenchymal stem cells alter bioavailability of cyclosporine, albeit at much lower doses and with fewer systemic adverse effects.
Topics: Male; Humans; Mice; Animals; Cyclosporine; Ki-67 Antigen; Umbilical Cord; Mesenchymal Stem Cells; Mesoderm; Immunosuppressive Agents; Proto-Oncogene Proteins c-bcl-2
PubMed: 36416704
DOI: 10.1097/SAP.0000000000003314 -
General and Comparative Endocrinology Sep 2020Renin or a renin-like enzyme evolved in ancestral vertebrates and is conserved along the vertebrate phylogeny. The ontogenic development of renin, however, is not well...
Renin or a renin-like enzyme evolved in ancestral vertebrates and is conserved along the vertebrate phylogeny. The ontogenic development of renin, however, is not well understood in nonmammalian vertebrates. We aimed to determine the expression patterns and relative abundance of renin mRNA in pre- and postnatal chickens (Gallus gallus, White Leghorn breed). Embryonic day 13 (E13) embryos show renal tubules, undifferentiated mesenchymal structures, and a small number of developing glomeruli. Maturing glomeruli are seen in post-hatch day 4 (D4) and day 30 (D30) kidneys, indicating that nephrogenic activity still exists in kidneys of 4-week-old chickens. In E13 embryos, renin mRNA measured by quantitative polymerase chain reaction in the adrenal glands is equivalent to the expression in the kidneys, whereas in post-hatch D4 and D30 maturing chicks, renal renin expressions increased 2-fold and 11-fold, respectively. In contrast, relative renin expression in the adrenals became lower than in the kidneys. Furthermore, renin expression is clearly visible by in situ hybridization in the juxtaglomerular (JG) area in D4 and D30 chicks, but not in E13 embryos. The results suggest that in chickens, renin evolved in both renal and extrarenal organs at an early stage of ontogeny and, with maturation, became localized to the JG area. Clear JG structures are not morphologically detectable in E13 embryos, but are visible in 30-day-old chicks, supporting this concept.
Topics: Animals; Chick Embryo; Chickens; Gene Expression Regulation; Juxtaglomerular Apparatus; Organogenesis; RNA, Messenger; Renin; Renin-Angiotensin System
PubMed: 32561435
DOI: 10.1016/j.ygcen.2020.113533 -
Frontiers in Pharmacology 2019Chronic kidney disease (CKD) is characterized by renal dysfunction, which is a common feature of other major diseases, such as hypertension and diabetes. Unilateral...
Chronic kidney disease (CKD) is characterized by renal dysfunction, which is a common feature of other major diseases, such as hypertension and diabetes. Unilateral ureteral obstruction (UUO) has been used as a model of CKD in experimental animals and consists of total obstruction of one kidney ureter. The UUO decreases renal blood flow, which promotes the synthesis of renin in the juxtaglomerular apparatus, the first step in renin-angiotensin system (RAS) cascade. RAS induces inflammation and remodeling, along with reduced renal function. However, it remains unknown whether intrarenal RAS (iRAS) is activated in early stages of CKD. Our objective was to characterize different iRAS components in the renal cortex and in the medulla in an early phase of UUO. Male C57BL/6 mice (8-12 weeks old) were subjected to UUO in the left kidney, or to sham surgery, and were euthanized after 7 days ( = 5/group). Renal function, renal inflammatory/remodeling processes, and iRAS expression were evaluated. UUO increased plasma creatinine, right renal hypertrophy (9.08 ± 0.31, < 0.05 vs. Sham), and tubular dilatation in the left kidney cortex (42.42 ± 8.19µm, < 0.05 vs. Sham). This correlated with the increased mRNA of IL-1β (1.73 ± 0.14, < 0.01 vs. Sham, a pro-inflammatory cytokine) and TGF-β1 (1.76 ± 0.10, < 0.001 vs. Sham, a pro-fibrotic marker). In the renal cortex of the left kidney, UUO increased the mRNA and protein levels of renin (in 35% and 28%, respectively, P < 0.05 vs. Sham). UUO decreased mRNA and protein levels for the (pro)renin receptor in the renal medulla (0.67 ± 0.036 and 0.88 ± 0.028, respectively, < 0.05 vs. Sham). Our results suggest that modulation of iRAS components depends on renal localization and occurs in parallel with remodeling and pro-inflammatory/pro-fibrotic mechanisms.
PubMed: 31803050
DOI: 10.3389/fphar.2019.01314 -
Cardiorenal Medicine 2021Clinical guidelines include diuretics for the treatment of heart failure (HF), not to decrease mortality but to decrease symptoms and hospitalizations. More attention... (Review)
Review
Clinical guidelines include diuretics for the treatment of heart failure (HF), not to decrease mortality but to decrease symptoms and hospitalizations. More attention has been paid to the worse outcomes, including mortality, associated with continual diuretic therapy due to hypochloremia. Studies have revealed a pivotal role for serum chloride in the pathophysiology of HF and is now a target of treatment to decrease mortality. The prognostic value of serum chloride in HF has been the subject of much attention. Mechanistically, the macula densa, a region in the renal juxtaglomerular apparatus, relies on chloride levels to sense salt and volume status. The recent discovery of with-no-lysine (K) (WNK) protein kinase as an intracellular chloride sensor sheds light on the possible reason of diuretic resistance in HF. The action of chloride on WNKs results in the upregulation of the sodium-potassium-chloride cotransporter and sodium-chloride cotransporter receptors, which could lead to increased electrolyte and fluid reabsorption. Genetic studies have revealed that a variant of a voltage-sensitive chloride channel (CLCNKA) gene leads to almost a 50% decrease in current amplitude and function of the renal chloride channel. This variant increases the risk of HF. Several trials exploring the prognostic value of chloride in both acute and chronic HF have shown mostly positive results, some even suggesting a stronger role than sodium. However, so far, interventional trials exploring serum chloride as a therapeutic target have been largely inconclusive. This study is a review of the pathophysiologic effects of hypochloremia in HF, the genetics of chloride channels, and clinical trials that are underway to investigate novel approaches to HF management.
Topics: Chlorides; Diuretics; Heart Failure; Humans; Sodium; Water-Electrolyte Imbalance
PubMed: 33873189
DOI: 10.1159/000515604 -
Hypertension (Dallas, Tex. : 1979) Aug 2020Juxtaglomerular cells are crucial for blood pressure and fluid-electrolyte homeostasis. The factors that maintain the life of renin cells are unknown. In vivo, renin...
Juxtaglomerular cells are crucial for blood pressure and fluid-electrolyte homeostasis. The factors that maintain the life of renin cells are unknown. In vivo, renin cells receive constant cell-to-cell, mechanical, and neurohumoral stimulation that maintain their identity and function. Whether the presence of this niche is crucial for the vitality of the juxtaglomerular cells is unknown. Integrins are the largest family of cell adhesion molecules that mediate cell-to-cell and cell-to-matrix interactions. Of those, β1-integrin is the most abundant in juxtaglomerular cells. However, its role in renin cell identity and function has not been ascertained. To test the hypothesis that cell-matrix interactions are fundamental not only to maintain the identity and function of juxtaglomerular cells but also to keep them alive, we deleted in vivo in cells of the renin lineage. In mutant mice, renin cells died by apoptosis, resulting in decreased circulating renin, hypotension, severe renal-vascular abnormalities, and renal failure. Results indicate that cell-to-cell and cell-to-matrix interactions via β1-integrin is essential for juxtaglomerular cells survival, suggesting that the juxtaglomerular niche is crucial not only for the tight regulation of renin release but also for juxtaglomerular cell survival-a sine qua non condition to maintain homeostasis.
Topics: Animals; Apoptosis; Cell Survival; Homeostasis; Integrin beta1; Juxtaglomerular Apparatus; Kidney Diseases; Mice; Mice, Knockout; Renal Artery; Renin
PubMed: 32594804
DOI: 10.1161/HYPERTENSIONAHA.120.14959 -
American Journal of Physiology. Renal... Oct 2018The secretion of the protease renin from renal juxtaglomerular cells is enhanced by subnormal extracellular calcium concentrations. The mechanisms underlying this...
The secretion of the protease renin from renal juxtaglomerular cells is enhanced by subnormal extracellular calcium concentrations. The mechanisms underlying this atypical effect of calcium have not yet been unraveled. We therefore aimed to characterize the effect of extracellular calcium concentration on calcium handling of juxtaglomerular cells and on renin secretion in more detail. For this purpose, we used a combination of experiments with isolated perfused mouse kidneys and direct calcium measurements in renin-secreting cells in situ. We found that lowering of the extracellular calcium concentration led to a sustained elevation of renin secretion. Electron-microscopical analysis of renin-secreting cells exposed to subnormal extracellular calcium concentrations revealed big omega-shaped structures resulting from the intracellular fusion and subsequent emptying of renin storage vesicles. The calcium concentration dependencies as well as the kinetics of changes were rather similar for renin secretion and for renovascular resistance. Since vascular resistance is fundamentally influenced by myosin light chain kinase (MLCK), myosin light chain phosphatase (MLCP), and Rho-associated protein kinase (Rho-K) activities, we examined the effects of MLCK-, MLCP-, and Rho-K inhibitors on renin secretion. Only MLCK inhibition stimulated renin secretion. Conversely, inhibition of MCLP activity lowered perfusate flow and strongly inhibited renin secretion, which could not be reversed by lowering of the extracellular calcium concentration. Renin-secreting cells and smooth muscle cells of afferent arterioles showed immunoreactivity of MLCK. These findings suggest that the inhibitory effect of calcium on renin secretion could be explained by phosphorylation-dependent processes under control of the MLCK.
Topics: Animals; Calcium; Calcium, Dietary; Juxtaglomerular Apparatus; Kidney; Mice; Myosin-Light-Chain Kinase; Phosphorylation; Renin; Urinary Tract Physiological Phenomena; rho-Associated Kinases
PubMed: 29357428
DOI: 10.1152/ajprenal.00554.2017 -
Hypertension (Dallas, Tex. : 1979) Jul 2019In patients with diabetic kidney disease (DKD), plasma renin activity is usually decreased, but there is limited information on urinary renin and its origin. Urinary... (Comparative Study)
Comparative Study
In patients with diabetic kidney disease (DKD), plasma renin activity is usually decreased, but there is limited information on urinary renin and its origin. Urinary renin was evaluated in samples from patients with longstanding type I diabetes mellitus and mice with streptozotocin-induced diabetes mellitus. Renin-reporter mouse model (Ren1d-Cre;mT/mG) was made diabetic with streptozotocin to examine whether the distribution of cells of the renin lineage was altered in a chronic diabetic environment. Active renin was increased in urine samples from patients with DKD (n=36), compared with those without DKD (n=38; 3.2 versus 1.3 pg/mg creatinine; P<0.001). In mice with streptozotocin-induced diabetes mellitus, urine renin was also increased compared with nondiabetic controls. By immunohistochemistry, in mice with streptozotocin-induced diabetes mellitus, juxtaglomerular apparatus and proximal tubular renin staining were reduced, whereas collecting tubule staining, by contrast, was increased. To examine the role of filtration and tubular reabsorption on urinary renin, mice were either infused with either mouse or human recombinant renin and lysine (a blocker of proximal tubular protein reabsorption). Infusion of either form of renin together with lysine markedly increased urinary renin such that it was no longer different between nondiabetic and diabetic mice. Megalin mRNA was reduced in the kidney cortex of streptozotocin-treated mice (0.70±0.09 versus 1.01±0.04 in controls, P=0.01) consistent with impaired tubular reabsorption. In Ren1d-Cre;mT/mG with streptozotocin-induced diabetes mellitus, the distribution of renin lineage cells within the kidney was similar to nondiabetic renin-reporter mice. No evidence for migration of cells of renin linage to the collecting duct in diabetic mice could be found. Renin mRNA in microdissected collecting ducts from streptozotocin-treated mice, moreover, was not significantly different than in controls, whereas in kidney cortex, largely reflecting juxtaglomerular apparatus renin, it was significantly reduced. In conclusion, in urine from patients with type 1 diabetes mellitus and DKD and from mice with streptozotocin-induced diabetes mellitus, renin is elevated. This cannot be attributed to production from cells of the renin lineage migrating to the collecting duct in a chronic hyperglycemic environment. Rather, the elevated levels of urinary renin found in DKD are best attributed to altered glomerular filteration and impaired proximal tubular reabsorption.
Topics: Animals; Biopsy, Needle; Cohort Studies; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Diabetic Nephropathies; Disease Models, Animal; Female; Glomerular Filtration Rate; Humans; Immunohistochemistry; Kidney Tubules, Collecting; Low Density Lipoprotein Receptor-Related Protein-2; Male; Mice; Mice, Transgenic; RNA, Messenger; Random Allocation; Reference Values; Renin; Sensitivity and Specificity; Urinalysis
PubMed: 31079532
DOI: 10.1161/HYPERTENSIONAHA.119.12873 -
In Vitro Cellular & Developmental... Feb 2019The aim of the present study was to investigate the renogenic characteristics of amniotic fluid stem cells (AFSCs) and to evaluate their in vitro differentiation...
The aim of the present study was to investigate the renogenic characteristics of amniotic fluid stem cells (AFSCs) and to evaluate their in vitro differentiation potential into renal proximal tubular-like cells and juxtaglomerular-like cells. We culture expanded AFSCs derived from rat amniotic fluid. The AFSCs grew as adherent spindle-shaped cells and expressed mesenchymal markers CD73, CD90, and CD105 as well as renal progenitor markers WT1, PAX2, SIX2, SALL1, and CITED1. AFSCs exhibited an in vitro differentiation potential into renal proximal tubular epithelial-like cells, as shown by the upregulation of expression of proximal tubular cell-specific genes like AQP1, CD13, PEPT1, GLUT5, OAT1, and OCT1. AFSCs could also be differentiated into juxtaglomerular-like cells as demonstrated by the expression of renin and α-SMA. The AFSCs also expressed pluripotency markers OCT4, NANOG, and SOX2 and could be induced into embryoid bodies with differentiation into all the three germ layers, highlighting the pluripotent nature of these cells. Our results show that amniotic fluid contains a population of primitive stem cells that express renal-progenitor markers and also possess the propensity to differentiate into two renal lineage cell types and, thus, may have a therapeutic potential in renal regenerative medicine.
Topics: Amniotic Fluid; Animals; Cell Differentiation; Cell Proliferation; Cell Shape; Embryoid Bodies; Immunophenotyping; Juxtaglomerular Apparatus; Kidney Tubules, Proximal; Kinetics; Rats, Wistar; Stem Cells
PubMed: 30645697
DOI: 10.1007/s11626-018-00315-2