BACKGROUND: Gitelman's syndrome is an autosomal recessive renal tubular disorder characterized by hypokalemic metabolic alkalosis, hypomagnesemia, and hypocalciuria. It is known to be caused by a mutation of SLC12A3 gene coding the sodium-chloride cotransporter (NCCT) in the distal tubule. The defect of NCCT in human renal tissues has not been investigated, and we tested whether the defect of NCCT can be detected in renal tissue of a patient with Gitelman's syndrome by using immunohistochemistry. METHODS: In an adult patient with Gitelman's syndrome, blood and urine samples were collected for measurement of biochemical parameters. Renal clearance study and gene analysis were performed. Immunohistochemistry was performed on the renal tissue of the patient using a rabbit polyclonal antibody directed against a synthetic peptide corresponding to a portion in the amino terminal tail for human NCCT. Normal human renal tissues from surgical nephrectomy due to renal cell carcinoma and renal biopsy tissues from patients with glomerulonephritis but without any electrolyte disturbance were used as controls. RESULTS: The patient had hypokalemic metabolic alkalosis, hypocalciuria and hypomagnesemia. Renal clearance study revealed a decrease in distal fractional chloride reabsorption after the administration of furosemide. SLC12A3 gene mutation (S967F) was found by direct sequencing method. Immunohistochemistry showed the absence of NCCT staining in the renal tissue of the patient. On the other hand, the immunostaining of other transporters was all positive in renal tissues from both Gitelman's syndrome patients and controls. CONCLUSIONS: We report the absence of intact NCCT in the renal tissue of a Gitelman's syndrome patient.
Adult ; Alkalosis ; Biopsy ; Carcinoma, Renal Cell ; Clinical Coding ; Furosemide ; Gitelman Syndrome* ; Glomerulonephritis ; Hand ; Humans ; Immunohistochemistry ; Nephrectomy ; Sodium Chloride Symporters ; Solute Carrier Family 12, Member 3*

Wnk kinase maintains cell volume, regulating various transporters such as sodium-chloride cotransporter, potassium-chloride cotransporter, and sodium-potassium-chloride cotransporter 1 (NKCC1) through the phosphorylation of oxidative stress responsive kinase 1 (OSR1) and STE20/SPS1-related proline/alanine-rich kinase (SPAK). However, the activating mechanism of Wnk kinase in specific tissues and specific conditions is broadly unclear. In the present study, we used a human salivary gland (HSG) cell line as a model and showed that Ca2+ may have a role in regulating Wnk kinase in the HSG cell line. Through this study, we found that the HSG cell line expressed molecules participating in the WNK-OSR1-NKCC pathway, such as Wnk1, Wnk4, OSR1, SPAK, and NKCC1. The HSG cell line showed an intracellular Ca2+ concentration ([Ca2+]i) increase in response to hypotonic stimulation, and the response was synchronized with the phosphorylation of OSR1. Interestingly, when we inhibited the hypotonically induced [Ca2+]i increase with nonspecific Ca2+ channel blockers such as 2-aminoethoxydiphenyl borate, gadolinium, and lanthanum, the phosphorylated OSR1 level was also diminished. Moreover, a cyclopiazonic acid-induced passive [Ca2+]i elevation was evoked by the phosphorylation of OSR1, and the amount of phosphorylated OSR1 decreased when the cells were treated with BAPTA, a Ca2+ chelator. Finally, through that process, NKCC1 activity also decreased to maintain the cell volume in the HSG cell line. These results indicate that Ca2+ may regulate the WNK-OSR1 pathway and NKCC1 activity in the HSG cell line. This is the first demonstration that indicates upstream Ca2+ regulation of the WNK-OSR1 pathway in intact cells.
Cell Line* ; Cell Size ; Gadolinium ; Humans ; Lanthanum ; Oxidative Stress ; Phosphorylation ; Phosphotransferases ; Salivary Glands* ; Sodium Chloride Symporters ; Sodium-Potassium-Chloride Symporters

Gitelman's syndrome is an autosomal recessive disorder characterized by hypokalemic metabolic alkalosis, hypomagnesemia, and hypocalciuria that has recently been reported to be linked to thiazide-sensitive Na-Cl cotransporter gene mutation. We have experienced one patient whose initial complaint was paresthesia of hand and feet, who had hypokalemic metabolic alkalosis, hypomagnesemia, and hypocalciuria. We report the case of Gitelman's syndrome with a brief review of related literature.
Alkalosis ; Foot ; Gitelman Syndrome ; Hand ; Humans ; Hypokalemia ; Paresthesia ; Receptors, Drug ; Sodium Chloride Symporters

Uninephrectomy (uNx) in young rats causes salt-sensitive hypertension (SSH). Alterations of sodium handling in residual nephrons may play a role in the pathogenesis. Therefore, we evaluated the adaptive alterations of renal sodium transporters according to salt intake in uNx-SSH rats. uNx or sham operations were performed in male Sprague-Dawley rats, and normal-salt diet was fed for 4 weeks. Four experimental groups were used: sham-operated rats raised on a high-salt diet for 2 weeks (CHH) or on a low-salt diet for 1 week after 1 week's high-salt diet (CHL) and uNx rats fed on the same diet (NHH, NHL) as the sham-operated rats were fed. Expression of major renal sodium transporters were determined by semiquantitative immunoblotting. Systolic blood pressure was increased in NHH and NHL groups, compared with CHH and CHL, respectively. Protein abundances of Na+/K+/2Cl- cotransporter (NKCC2) and Na+/Cl- cotransporter (NCC) in the CHH group were lower than the CHL group. Expression of epithelial sodium channel (ENaC)-gamma increased in the CHH group. In contrast, expressions of NKCC2 and NCC in the NHH group didn't show any significant alterations, compared to the NHL group. Expressions of ENaC-alpha and ENaC-beta in the NHH group were higher than the CHH group. Adaptive alterations of NKCC2 and NCC to changes of salt intake were different in the uNx group, and changes in ENaC-alpha and ENaC-beta were also different. These altered regulations of sodium transporters may be involved in the pathogenesis of SSH in the uNx rat model.
Animals ; Blood Pressure ; Diet ; Diet, Sodium-Restricted ; Epithelial Sodium Channels ; Handling (Psychology) ; Humans ; Hypertension ; Immunoblotting ; Male ; Nephrectomy ; Nephrons ; Rats ; Rats, Sprague-Dawley ; Salicylamides ; Social Control, Formal ; Sodium ; Sodium Chloride Symporters ; Sodium-Potassium-Chloride Symporters

Heart failure is the pathophysiological state characterized by ventricular dysfunction and associated clinical symptoms. Decreased cardiac output or peripheral vascular resistance lead to arterial underfilling. That is an important signal which triggers multiple neurohormonal systems to maintain adequate arterial pressure and peripheral perfusion of the vital organs. The kidney is the principal organ affected when cardiac output declines. Alterations of hemodynamics and neurohormonal systems in heart failure result in renal sodium and water retention. Activation of sympathetic nervous system, renin-angiotensin-aldosterone system and non-osmotic vasopressin release stimulate the renal tubular reabsorption of sodium and water. Dysregulation of aquaporin-2 and sodium transporters also play an important role in the pathogenesis of renal sodium and water retention.
Aquaporin 2 ; Aquaporins ; Arterial Pressure ; Cardiac Output ; Epithelial Sodium Channels ; Heart ; Heart Failure ; Hemodynamics ; Kidney ; Perfusion ; Renin-Angiotensin System ; Retention (Psychology) ; Sodium ; Sodium Chloride Symporters ; Sodium-Potassium-Chloride Symporters ; Sympathetic Nervous System ; Vascular Resistance ; Vasopressins ; Ventricular Dysfunction ; Water-Electrolyte Imbalance

Gitelman's syndrome is a rare autosomal recessive, inherited renal tubular disorder, first described by Gitelman et al. in 1966, and it is characterized by hypokalemic metabolic alkalosis, hypomagnesemia, salt wasting, normal to low blood pressure and rather low urinary calcium excretion rates with elevated plasma renin activity. This syndrome is caused by inactivating mutation in the SLC12A3 gene coding for the thiazide-sensitive sodium chloride cotransporter in the distal convoluted tubule. In most of the patients with Gitelman's syndrome, the disease manifests with transient episodes of muscular weakness and tetany in the adulthood. Herein, we report a case of Gitelman's syndrome atypically presented with chest pain and syncope.
Alkalosis ; Calcium ; Chest Pain* ; Clinical Coding ; Gitelman Syndrome* ; Humans ; Hypotension ; Muscle Weakness ; Plasma ; Renin ; Sodium Chloride Symporters ; Syncope* ; Tetany ; Thorax*

Occludin is a cell adhesion molecule that is abundantly expressed in the kidney. However, the expression pattern in various renal epithelial cells is not well established. The purpose of this study was to determine the cellular localization along the tubular epithelial cells in the kidney. Kidneys from adult pigs crossbred of Yorkshire, Landrace and Duroc (three breeds) were processed for immunohistochemistry. Thiazide sensitive sodium chloride cotransporter (TSC), Na+-KATPase bat1, calbindinD28k, and H+-ATPase were used to identify the thick ascending limb, distal convoluted tubule, connecting tubule, and collecting duct, respectively. In the pig kidney, occludin was expressed in the apical domain of the tubular epithelial cells. The immunoreactivity of occludin was strongest in the collecting duct, and then gradually decreased in the connecting tubule, distal convoluted tubule, and thick ascending limb. Occludin expression was weak in the thin limbs of the loop of henle and in the proximal tubule in the pig kidney. These results suggest that occludin may be a major adhesion molecule in distal tubular epithelial cells and play a critical role in maintaining epithelial polarity of these nephron segments.
Adult ; Cell Adhesion ; Epithelial Cells ; Extremities ; Humans ; Immunohistochemistry ; Kidney ; Loop of Henle ; Nephrons ; Occludin ; Sodium Chloride Symporters ; Swine

The present study was done to determine whether endogenous nitric oxide (NO) plays a role in the regulation of sodium transporters in the kidney. Male Sprague-Dawley rats were treated with NG-nitro-L-arginine methyl ester (L-NAME, 100 mg/L drinking water) for 4 weeks. Control rats were supplied with tap water without drugs. Expression of Na, K-ATPase, type 3 Na/H exchanger (NHE3), Na/K/2Cl cotransporter (BSC1), and thiazide-sensitive Na/Cl cotransporter (TSC) proteins was determined in the kidney by Western blot analysis. Catalytic activity of Na,K-ATPase was also determined. The treatment with L-NAME significantly and steadily increased the systemic blood pressure. Total and fractional excretion of urinary sodium decreased significantly, while creatinine clearance remained unaltered. Neither plasma renin activity nor aldosterone concentration was significantly altered. The alpha1 subunit expression and the catalytic activity of Na, K-ATPase were increased in the kidney. The expression of NHE3, BSC1 and TSC was also increased significantly. These results suggest that endogenously-derived NO exerts a tonic inhibitory effect on the expression of sodium transporters, including Na, K-ATPase, NHE3, BSC1, and TSC, in the kidney.
Animals ; Blotting, Western ; Carrier Proteins/*biosynthesis ; Enzyme Inhibitors/pharmacology ; Kidney/drug effects/metabolism ; Male ; NG-Nitroarginine Methyl Ester/*pharmacology ; Na(+)-K(+)-Exchanging ATPase/biosynthesis ; Nitric Oxide Synthase/*antagonists & inhibitors/metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, Drug/biosynthesis ; Sodium/*metabolism ; Sodium Chloride Symporters/biosynthesis ; Sodium-Hydrogen Antiporter/biosynthesis ; Sodium-Potassium-Chloride Symporters/biosynthesis

Hemodynamic factors play an important role in the development and/or progression of diabetic nephropathy. We hypothesized that renal sodium transporter dysregulation might contribute to the hemodynamic alterations in diabetic nephropathy. Otsuka Long Evans Tokushima Fatty (OLETF) rats were used as an animal model for type 2 diabetes. Long Evans Tokushima (LETO) rats were used as controls. Renal sodium transporter regulation was investigated by semiquantitative immunoblotting and immunohistochemistry of the kidneys of 40-week-old animals. The mean serum glucose level in OLETF rats was increased to 235+/-25 mg/dL at 25 weeks, and the hyperglycemia continued up to the end of 40 weeks. Urine protein/ creatinine ratios were 10 times higher in OLETF rats than in LETO rats. At 40th week, the abundance of the epithelial sodium channel (ENaC) beta-subunit was increased in OLETF rats, but the abundance of the ENaC gamma-subunit was decreased. No significant differences were observed in the ENaC alpha-subunit or other major sodium transporters. Immunohistochemistry for the ENaC beta-subunit showed increased immunoreactivity in OLETF rats, whereas the ENaC gamma-subunit showed reduced immunoreactivity in these rats. In OLETF rats, ENaC beta-subunit upregulation and ENaC gamma-subunit downregulation after the development of diabetic nephropathy may reflect an abnormal sodium balance.
Animals ; Blood Glucose/analysis ; Diabetes Mellitus, Type 2/*metabolism ; *Disease Models, Animal ; Epithelial Sodium Channel/*analysis ; Hypertension/complications ; Immunoblotting ; Immunohistochemistry ; Kidney/*metabolism ; Male ; Rats ; Sodium/*metabolism ; Sodium-Hydrogen Antiporter/genetics ; Sodium-Potassium-Chloride Symporters/genetics

OBJECTIVETo investigate the association of thiazide-sensitive Na+ -Cl* cotransporter (TSC) gene 1784C/T and 2736G/A polymorphisms with the risk of essential hypertension (EH) in a Han nationality population.

METHODSA community-based, case-control study including 190 EH patients and 94 sex- and age-matched controls was conducted. Genotypes of TSC gene 1784C/T and 2736G/A polymorphisms were analyzed by gene chip technology.

RESULTSThe genotype (1784C/T CC, CT, TT:87, 88, 15 vs 36, 52, 6û2736G/A GG, AG, AA:167, 22, 1 vs 83, 10, 1) and alleles frequency (1784C/T C, T:68.9%, 31.1% vs 66.0%, 34.0%; 2736G/A G,A:93.7%, 6.3% vs 93.6%, 6.4%) distribution of 1784C/T and 2736G/A showed no significant difference between the EH group and the control group (P >0.05). Moreover, no significant difference was observed in the frequencies distribution of four haplotypes (P > 0.05); Logistic regression analysis of haplotypes showed that the risk of EH had no significant difference in the population with different haplotypes (P > 0.05).

CONCLUSIONThe 1784C/T and 2736G/A polymorphisms of TSC gene may not play an important role in the etiology of EH in a Han nationality population. The studies in the future are warranted to validate our findings.

Female ; Gene Frequency ; Genetic Predisposition to Disease ; Haplotypes ; Humans ; Hypertension ; epidemiology ; genetics ; Male ; Middle Aged ; Polymorphism, Genetic ; Polymorphism, Single Nucleotide ; Receptors, Drug ; genetics ; Risk ; Sodium Chloride Symporters ; genetics