Nephrotoxicity is a major limiting factor in the use of aminoglycoside antibiotics, the mechanisms for which are still speculative. To clarify the mechanisms of renal tubular cell death induced by aminoglycosides, we examined the renal proximal tubule-like cell line, LLC-PK1, after inducing apoptosis through a chronic treatment with gentamicin (GM). Changes in the expression of the Fas were also investigated. On flow cytometric analysis, 5.7 +/- 3.3% of the control cells appeared in a region of decreased forward light scatter and increased side light scatter, where both indices represent the characteristics of apoptotic cell death. Compared to the control, treatment with 10 mM of GM for 15 days significantly increased the proportion of cells in the apoptotic region to 23.9 +/- 8.5%. This finding was supported by electrophoretic analysis of the DNA extracted from the GM-treated cells, where a series of bands corresponding to integer multiples of 180 to 200 base pairs was visualized. However, the 15-day GM treatment did not cause a significant elevation in the expression of the 45 kD Fas protein, the cell surface molecule that stimulates apoptosis, by Western blot analysis. In conclusion, long-term exposure to GM induces apoptosis of the renal tubular epithelial cells, and this process may contribute to some of the aminoglycoside nephrotoxicities. Further studies are needed on the mechanism(s) of apoptosis induced by GM.
Animal ; Antibiotics, Aminoglycoside/toxicity* ; Antigens, CD95/analysis ; Apoptosis/drug effects* ; Cell Line ; Gentamicins/toxicity* ; Kidney Tubules, Proximal/pathology ; Kidney Tubules, Proximal/drug effects* ; Swine

Perlman syndrome is a rare autosomal recessive congenital overgrowth syndrome caused by pathogenic variants of the DIS3L2 gene at 2q37 region. Clinically this syndrome is characterized by polyhydramnios, macrosomia, distinctive facial appearance, and renal dysplasia. Prognosis of the disease is poor, and survivors usually have mental delay and a high risk of developing Wilms tumor. At present, the pathogenesis of this disease is still poorly understood. This article intends to provide a review for this disease.
Female ; Fetal Macrosomia ; Humans ; Kidney Tubules, Proximal ; Pregnancy ; Syndrome ; Wilms Tumor

Perinatal asphyxia can cause ischemic injury to immature kidney of neonates. Proximal renal tubule is the most sensitive area, showing various manifestations ranging from mild reversible injury to irreversible tubular necrosis. Aminoglycosides can be nephrotoxic in therapeutic range in immature or damaged kidney. Thess are the very important factors to be taken into corsideration on fluid therapy and nephrotoxic drugs in neonates. The purpose of this study is to detect renal dysfunction resulting from asphyxia and gentamicin treatment. The results were as follows; 1) Urinary 2-microglobulin concentration was significantly higher in neonatal asphyxia group irrespective of meconium stain (p<0.05). The group with neonatal asphyxia only (Ia) showed a gradual decline in urinary 2-microglobulin concentration and no significant difference shown when compared with control group on 7 days old (p>0.05). The group with neonatal asphyxia and meconium stain (Ib) received gentamicin for 7 days. Their urinary 2-microglobulin concentration dropped on 4 the day and increased again on 7 th day (p<0.05). The group with meconium stain only(3) showed no significant difference in urinary 2-microglobulin concentration when compared with control group (p>0.05). 2) No differences were shown in serum creatinine, serum sodium level and urinary creatinine concentrations between each group (p>0.05). 3) No differences were shown in creatinine clearance between each group (p>0.05).Fractional excretion of urinary sodium (FENa) was significantly higher on lst day in group, I, but no differences were shown afterwards (p>0.05). 4) There is no relationship between urinary 2-microglobulin concentration and serum creatinine level, creatinine clearance of FENa. 5) No differences were shown in incidence of renal dysfunction between each group. In conclusion, acute tubular injury by perinatal asphyxia recovered soon after birth. But nephrotoxic gentamicin worsened the recovering tubular injury. In case of mild fetal hypoxia without neonatal asphyxia, proximal tubular injury was not significant.
Aminoglycosides ; Asphyxia* ; Creatinine ; Fetal Hypoxia ; Fluid Therapy ; Gentamicins* ; Humans ; Incidence ; Infant, Newborn* ; Kidney ; Kidney Tubules, Proximal ; Meconium ; Necrosis ; Parturition ; Sodium

OBJECTIVETo investigate the expression and function of PKD1 and PKD2 in different kidney tissues and cell lines.

METHODSImmunoprecipitation, Western blotting, In situ hybridization and immunohistochemical staining methods were used to observe the expression of PKD1 mRNA and PKD2 mRNA and their protein abundance in different kidney tissues and cell lines.

RESULTSCoordinate expressions of PKD1 and PKD2 were found in all kidney tissues and cell lines. Distribution of PKD1 mRNA and PKD2 mRNA and their protein polycystin-1 and polycystin-2 in normal human adult kidney tissue were mainly expressed in the medullary collecting ducts and distal tubules. Positive staining was also found in the majority of cyst-lining epithelial cells of PKD1 cystic kidney tissue, PKD1 cyst-lining epithelia cell line and LLC-PK1. The expression level of them in cystic epithelia of ADPKD kidney tissue was much higher than that in adult renal tubules (P < 0.01).

CONCLUSIONSSimilar expression pattern of PKD1 and PKD2 and their different tissue distribution in different kidney tissues show that the molecular mutuality of PC-1 and PC-2 might be the base of their functional correlation. Polycystins might play an important role in the maintenance of tubular architecture.

Adult ; Animals ; Cell Line ; Gene Expression ; Humans ; Kidney ; metabolism ; Kidney Tubules, Collecting ; metabolism ; Kidney Tubules, Distal ; metabolism ; Kidney Tubules, Proximal ; cytology ; Polycystic Kidney, Autosomal Dominant ; pathology ; RNA, Messenger ; biosynthesis ; genetics ; Swine ; TRPP Cation Channels ; metabolism

HCO3(-) reabsorption in the renal tubules plays a critically important role in maintaining the global acid-base balance. Loss of HCO3(-) causes metabolic acidosis. Proximal renal tubule is the major site for HCO3(-) reabsorption, accounting for more than 80% of total HCO3(-) reabsorption along the nephron. Over the past more than half centuries, tremendous progresses have been made on understanding the molecular mechanisms underlying the HCO3(-) reabsorption in proximal tubules. The transepithelial movement of HCO3(-) involves the coordinated operation of machineries on both the apical and the basolateral membranes of the epithelial cells. On the apical domain, Na(+)-H(+) exchanger NHE3 and the vacuolar H(+)-ATPase are two major pathways mediating the apical uptake of HCO3(-)-related species. Taken together, NHE3 and H(+)-ATPase are responsible for about 80% of HCO3(-) reabsorption in the proximal tubule. The remaining 20% is likely mediated by pathways yet to be characterized. On the basolateral membrane, NBCe1 represents the only major known pathway mediating the extrusion of HCO3(-) coupled with Na(+) into the interstitial space. In the present article, we provide a historical view about the studies on the mechanisms of HCO3(-) reabsorption since 1940s. Moreover, we summarize the latest progresses emerging over the past decade in the physiological as well as pathological roles of acid-base transporters underlying the HCO3(-) reabsorption in proximal tubules.
Acidosis ; physiopathology ; Animals ; Bicarbonates ; metabolism ; Humans ; Kidney Tubules, Proximal ; physiopathology ; Sodium-Hydrogen Exchangers ; physiology ; Vacuolar Proton-Translocating ATPases ; physiology

The present study was designed to investigate the effect of administration of adrenomedullin (ADM) into subfornical organ (SFO) on renal tubular Na(+),K(+)-ATPase activity in rats. Rats under anesthesia were injected with ADM 0.1 mL (20 ng/mL) via an implanted cannula into SFO (n=6). Plasma ADM and serum endogenous digitalis-like factor (EDLF) levels were assayed with radioimmunoassay, and urine samples were collected via a canoula intubated in bladder. Urinary sodium concentration was assayed with flame spectrophotometry. Single proximal renal tubule segments were obtained by hand under stereomicroscope and its Na(+),K(+)-ATPase activity was measured by liquid scintillation counting. In addition, single proximal renal tubule segments from normal rats (n=6) were incubated with serum from animals administered with ADM into SFO, and then the Na(+),K(+)-ATPase activity was determined. The results showed that both urinary volume and sodium excretion amounted to the peak value at 30 min after ADM administration, and sustained a significant high level at 60 min (P<0.01). At 30 min after ADM administration, there was a significant increase in serum EDLF and a decrease in Na(+),K(+)-ATPase activity of proximal tubule (P<0.01, respectively), but not in plasma ADM level. Na(+),K(+)-ATPase activity was decreased significantly in single proximal renal tubule segments from normal rats incubated with serum from rats administered with ADM into SFO (P<0.01). These results suggest that the diuretic and natriuretic responses following administration of ADM into SFO are associated with the inhibition of renal tubule Na(+),K(+)-ATPase activity. The inhibition of renal tubule Na(+),K(+)-ATPase activity is related to the increase in the serum level of EDLF.
Adrenomedullin ; pharmacology ; Animals ; Kidney Tubules, Proximal ; drug effects ; enzymology ; Rats ; Sodium-Potassium-Exchanging ATPase ; metabolism ; Subfornical Organ

An improved approach for determination of Na(+)-K(+)-ATPase activity in single proximal renal tubule of rat reported by Doucet and his colleagues has been suggested. The single proximal renal tubules were isolated by hand under stereomicroscope from collagenase II-treated renal cortical tissue in rats. The length of every single renal tubule segment obtained was measured. The single proximal renal tubules were treated with a hypoosmotic solution and with freeze-thaw successively, before incubation with [gamma-(32)P]-ATP. (32)Pi hydrolyzed from [gamma-(32)P]ATP by Na(+)-K(+)-ATPase in the single proximal renal tubules was assayed by liquid scintillation counting. The activity of Na(+)-K(+)-ATPase in the single proximal renal tubules was calculated by applying a modified formula. There was no significant difference in the measurement result of Na(+)-K(+)-ATPase activity between the method of Doucet et al. and the improved one, but the latter has advantage of less time, less reagents and being easy to operate.
Adenosine Triphosphate ; metabolism ; Animals ; Kidney Tubules, Proximal ; enzymology ; Male ; Microscopy ; Rats ; Rats, Wistar ; Sodium-Potassium-Exchanging ATPase ; metabolism ; Time Factors

Cystinuria is an autosomal recessive disease characterized by impaired transport of cystine and dibasic amino acids in the proximal renal tubule, resulting in the formation of cystine stones. It is believed to account for about 1% of all kidney stones and up to 10% of pediatric stones. Here we report a case of cystinuria with multiple renal stones confirmed by genetic mutational analysis. An 8-month-old girl was admitted to AMC with persistent fever and multiple renal stones. A renal sonogram showed multiple stones at the right renal pelvis, right distal ureter, and left renal medullary portion. An approximately 1 cm renal stone was extracted spontaneously, and stone analysis revealed it to be composed entirely of cystine. Cystinuria was confirmed by increased urine dibasic amino acid levels, including cysteine, and genetic mutational analysis showed the patient to be a homozygote for the pathogenic c. 1820del (p.L607fs) of SLC3A1. Despite treatment with oral hydration and urinary alkalinization, and restricted intake of animal protein, the stones increased in size and number. The patient has since been treated with tiopronin.
Amino Acids, Diamino ; Animals ; Cysteine ; Cystine ; Cystinuria* ; Female* ; Fever ; Homozygote ; Humans ; Infant* ; Kidney Calculi ; Kidney Pelvis ; Kidney Tubules, Proximal ; Tiopronin ; Ureter ; Urolithiasis

A number of acid-base or electrolyte disorders are associated with decreased or increased HCO3- reabsorption in the renal tubules. There has been a general agreement that potassium depletion induces and maintains metabolic alkalosis in rats. However, many researchers have approached such issue only from functional studies to investigate Na+/H+ exchanger (NHE-3) and Na+/HCO(3-) cotransporter (NBC) activity which closely relates to potassium depletion. In addition the results obtained vary according to their researchers. Thus the present study was employed Western blot analysis and immunohistochemistry together, to examine the alterations of expression and distribution of NHE-3 and NBC-1 with reference to HCO3- reabsorption in the kidneys of rats fed potassium free diets according to the periods. Western blot analysis demonstrated that NHE-3 protein, ~83 kDa at molecular mass, was abundantly expressed in normal group. All potassium-depleted groups showed significantly increased NHE-3 protein compared to normal group. NBC-1 protein, ~110 kDa at molecular mass, was moderately expressed in normal group. All potassium-depleted groups had much higher amounts of the protein than normal group. There was a highly increased amount of NBC-1 protein especially in K-depleted 1 week group. Immunohistochemistry showed positive immunoreactivity of NHE-3 in the apical membranes and brush borders of proximal renal tubule cells. Its reactivity was most prominent in the S3.S1 and S2 had moderate immunoreactivity. Potassium-depleted groups had an identical pattern of cellular labeling of NHE-3 protein compared with that of normal group. However the signal intensity of NHE-3 protein in potassium-depleted groups was much higher than that of normal group. Immunoreactivity of NBC-1 was observed exclusively in the basolateral plasma membranes of proximal tubule cells. There was a strong reactivity in the S1 and S2, whereas S3 did not show any reactivity. Potassium-deprived rats exhibited an identical pattern of cellular labeling of NBC-1 protein compared with that of normal rats. However, the signal intensity of NBC-1 protein was markedly increased in potassium-deprived rats. These results suggest that increased NHE-3 and NBC-1 expression resulted from potassium depletion in the renal proximal tubules, enhances HCO3-reabsorption and consequently maintains metabolic alkalosis.
Alkalosis ; Animals ; Bicarbonates* ; Blotting, Western ; Cell Membrane ; Diet ; Hypokalemia ; Immunohistochemistry ; Kidney Tubules, Proximal ; Kidney* ; Membranes ; Microvilli ; Potassium ; Rats* ; Social Control, Formal*

Adefovir dipivoxil (ADV) and tenofovir disoproxil fumarate (TDF) are nucleotide analogues used to treat chronic hepatitis B (CHB) infection. Nephrotoxicity associated with the use of these medications causes Fanconi syndrome, a rare condition involving generalized dysfunction of the proximal renal tubule causing impaired reabsorption of glucose, uric acid, and phosphate. Fanconi syndrome has been previously reported in patients with human immunodeficiency virus (HIV) or HIV-CHB coinfection treated with other antiretroviral therapies. However, it is rarely reported in patients with CHB monoinfection. We observed a case of Fanconi syndrome in a 61-year-old woman with CHB monoinfection and a history of long-term ADV therapy (42 months), followed by TDF treatment for 9 months. She presented with ankle pain and a tingling sensation in both lower extremities. Laboratory tests revealed hypokalemia, hypocalcemia, hypophosphatemia, hypouricemia, proteinuria, and glycosuria. This case illustrates the importance of recognizing Fanconi syndrome associated with nucleotide analogue treatment and the need to carefully observe symptoms and monitor renal function in these patients.
Ankle ; Coinfection ; Fanconi Syndrome* ; Female ; Glucose ; Glycosuria ; Hepatitis B, Chronic* ; Hepatitis, Chronic* ; HIV ; Humans ; Hypocalcemia ; Hypokalemia ; Hypophosphatemia ; Kidney Tubules, Proximal ; Lower Extremity ; Middle Aged ; Proteinuria ; Sensation ; Uric Acid