ABSTRACT
BACKGROUND: Low nephron number at birth is associated with a high risk of CKD in adulthood because nephrogenesis is completed in utero. Poor intrauterine environment impairs nephron endowment via an undefined molecular mechanism. A calorie-restricted diet (CRD) mouse model examined the effect of malnutrition during pregnancy on nephron progenitor cells (NPCs). METHODS: Daily caloric intake was reduced by 30% during pregnancy. mRNA expression, the cell cycle, and metabolic activity were evaluated in sorted Six2 NPCs. The results were validated using transgenic mice, oral nutrient supplementation, and organ cultures. RESULTS: Maternal CRD is associated with low nephron number in offspring, compromising kidney function at an older age. RNA-seq identified cell cycle regulators and the mTORC1 pathway, among other pathways, that maternal malnutrition in NPCs modifies. Metabolomics analysis of NPCs singled out the methionine pathway as crucial for NPC proliferation and maintenance. Methionine deprivation reduced NPC proliferation and lowered NPC number per tip in embryonic kidney cultures, with rescue from methionine metabolite supplementation. Importantly, in vivo, the negative effect of caloric restriction on nephrogenesis was prevented by adding methionine to the otherwise restricted diet during pregnancy or by removing one Tsc1 allele in NPCs. CONCLUSIONS: These findings show that mTORC1 signaling and methionine metabolism are central to the cellular and metabolic effects of malnutrition during pregnancy on NPCs, contributing to nephrogenesis and later, to kidney health in adulthood.
Subject(s)
Malnutrition/physiopathology , Mechanistic Target of Rapamycin Complex 1/metabolism , Methionine/metabolism , Nephrons/embryology , Stem Cells/metabolism , Animals , Caloric Restriction , Cell Cycle , Cell Proliferation/drug effects , Disease Models, Animal , Female , Gene Expression , Homeodomain Proteins/genetics , Malnutrition/metabolism , Metabolomics , Methionine/administration & dosage , Methionine/deficiency , Methionine/pharmacology , Mice , Mice, Transgenic , Nephrons/metabolism , Nephrons/pathology , Organ Culture Techniques , Pregnancy , RNA, Messenger , RNA-Seq , Signal Transduction , Stem Cells/physiology , Transcription Factors/genetics , Tuberous Sclerosis Complex 1 Protein/geneticsABSTRACT
Chronic kidney disease is the main cause of mortality in patients with tuberous sclerosis complex (TSC) disease. The mechanisms underlying TSC cystic kidney disease remain unclear, with no available interventions to prevent cyst formation. Using targeted deletion of TSC1 in nephron progenitor cells, we showed that cysts in TSC1-null embryonic kidneys originate from injured proximal tubular cells with high mTOR complex 1 activity. Injection of rapamycin to pregnant mice inhibited the mTOR pathway and tubular cell proliferation in kidneys of TSC1-null offspring. Rapamycin also prevented renal cystogenesis and prolonged the life span of TSC newborns. Gene expression analysis of proximal tubule cells identified sets of genes and pathways that were modified secondary to TSC1 deletion and rescued by rapamycin administration during nephrogenesis. Inflammation with mononuclear infiltration was observed in the cystic areas of TSC1-null kidneys. Dexamethasone administration during pregnancy decreased cyst formation by not only inhibiting the inflammatory response, but also interfering with the mTORC1 pathway. These results reveal mechanisms of cystogenesis in TSC disease and suggest interventions before birth to ameliorate cystic disease in offspring.
Subject(s)
Dexamethasone/pharmacology , Kidney Diseases, Cystic/prevention & control , Sirolimus/pharmacology , Tuberous Sclerosis/prevention & control , Animals , Female , Kidney/metabolism , Kidney Diseases, Cystic/drug therapy , Mechanistic Target of Rapamycin Complex 1/drug effects , Mice, Transgenic , Pregnancy , Tuberous Sclerosis/genetics , Tuberous Sclerosis Complex 1 Protein/drug effects , Tuberous Sclerosis Complex 1 Protein/genetics , Tumor Suppressor Proteins/geneticsABSTRACT
AIM: To evaluate the diagnostic value of serial biochemical blood tests in the diagnosis of biliary colic. METHODS: Files were reviewed of 1039 patients who were admitted to the Share'e Zedek Medical Center emergency department between the years 2012-2013, and received the coding of acute biliary disease. Of these, the first 100 cases were selected that met the following criteria: (1) a diagnosis of biliary colic or symptomatic cholelithiasis; (2) at least two biochemical blood tests performed; and (3) 18 years of age or older. Patients with other acute biliary diseases were excluded. The biochemical profile of the patients was analyzed as were their clinical and radiological findings. RESULTS: Three-quarters of the patients were women, whose average age of 37 years was younger than the average of the men, at 50 years. According to their histories, 47% of the patients had previously known cholelithiasis. Pain in either the right upper quadrant or the epigastrium was the presenting symptom in 93% cases. The greatest change in serum biochemical results was seen during the first day of the patients' admissions. Alanine aminotransferase (ALT) showed the highest initial rise above the reference range, followed by aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), bilirubin and alkaline phosphatase (ALKP) - all these increases were statistically significant (P < 0.05). AST showed the sharpest decline followed by bilirubin and ALT. GGT and ALKP did not fall. A sharp rise and fall in liver enzymes, especially during the first day, most prominently in AST and ALT, was seen in 70% percent of cases. In 65% of cases trans-abdominal sonography did not give diagnostic findings. CONCLUSION: Serial serum liver enzyme measurements are helpful in the initial diagnosis of acute biliary colic.
