Cardiac resistance to growth hormone in uremia.

Background: Cardiovascular disease is a major cause of death in end-stage renal disease (ESRD). Since growth hormone is required for maintaining normal cardiac structure and function and as growth hormone has a salutary effect on cardiac remodeling in disease, we postulated that if cardiac resistance to growth hormone develops in chronic renal failure (CRF) this may predispose to the cardiomyopathy of uremia. We set out to test whether in CRF there is resistance to the cardiac action of growth hormone and whether this defect might be caused by altered growth hormone signaling.

Growth hormone resistance in uremia, a role for impaired JAK/STAT signaling.

Resistance to growth hormone (GH) is a significant complication of advanced chronic renal failure. Thus while the circulating GH levels are normal or even elevated in uremia, resistance to the hormone leads to stunting of body growth in children and contributes to muscle wasting in adults. Insensitivity to GH is the consequence of multiple defects in the GH/insulin-like growth factor-1 (IGF-1) system.

Chronic uremia attenuates growth hormone-induced signal transduction in skeletal muscle.

Malnutrition and muscle wasting are common in chronic renal failure (CRF) and adversely affect morbidity and mortality. Contributing to the muscle wasting is resistance to growth hormone (GH). For testing whether impaired GH signaling is a cause of the skeletal muscle GH resistance and for elucidating its mechanisms, muscle GH signaling and action were studied in GH-deficient rats with surgically induced CRF and sham-operated pairfed control rats.

Plasma protein extravasation and vascular endothelial growth factor expression with endothelial nitric oxide synthase induction in gentamicin-induced acute renal failure in rats.

Microvascular hyperpermeability to plasma proteins via vascular endothelial growth factor (VEGF) with endothelial nitric oxide synthase (eNOS) induction may contribute to wound healing through matrix remodeling. However, vascular hyperpermeability is not examined in acute renal failure (ARF), a unique form of wound healing. Subcutaneous injection of gentamicin (400 mg/kg per day for 2 days in divided doses every 8 h) in rats increased serum creatinine levels and induced tubular damage, which peaked at day 6, after the last gentamicin injection.

Important role for fibronectin-EIIIA during renal tubular repair and cellular recovery in uranyl acetate-induced acute renal failure of rats.

The present study was designed to identify the source and kinetics of an alternatively spliced "embryonic" cellular fibronectin EIIIA (cFn-EIIIA) in relation to regenerating renal tubules in uranyl acetate (UA)-induced acute renal failure (ARF) in rats. Damage of the proximal tubules was found as early as day 2 after induction of ARF, peaked at day 5, and was almost substituted by epithelial relining by day 7. Immunohistochemistry showed de novo deposition of cFn-EIIIA in peritubular regions as early as day 2, then on the tubular basement membrane (TBM) after day 4.

Temporary changes in macrophages and MHC class-II molecule-expressing cells in the tubulointerstitium in response to uranyl acetate-induced acute renal failure in rats.

The present study was designed to asses the dynamic changes in macrophages (Møs) with or without expression of major histocompatibility complex (MHC) class-II molecule in response to uranyl acetate-induced acute renal failure (ARF) in rats. ED1+ monocytes/Møs infiltrated into the interstitium as early as day 2, peaked in number on day 5 after uranyl acetate-induced ARF. ED1+ cells did not correlate with necrotic tubules but accumulated abundantly in the vicinity of the Ki67+ regenerating proximal tubules around days 4-5.

Relation of distal nephron changes to proximal tubular damage in uranyl acetate-induced acute renal failure in rats.

Aims: To elucidate the pathophysiological roles of the changes of distal nephron in uranyl acetate (UA)-induced acute renal failure (ARF), we investigated the relation of changes of constituent molecules in distal nephron to proximal tubular damage and repair in UA-treated rats.

Methods: ARF was induced in rats by intravenous injection of UA, and all rats received bromodeoxyuridine (BrdU) intraperitoneally 1 h before sacrifice.

Results: Proximal tubular damage with necrosis appeared as early as day 2, mainly in the outer stripe of outer medulla and reached a peak level at day 5.

Mechanisms and kinetics of Bowman's epithelial-myofibroblast transdifferentiation in the formation of glomerular crescents.

Background: We investigated the mechanisms and kinetics of Bowman's epithelial-myofibroblast transdifferentiation in the formation of glomerular crescents.

Methods: Crescentic glomerulonephritis was induced by i.v.

Mycophenolate mofetil inhibits regenerative repair in uranyl acetate-induced acute renal failure by reduced interstitial cellular response.

We recently reported that transient appearance of interstitial myofibroblasts and infiltrating macrophages might play a role in cellular recovery in uranyl acetate (UA)-induced acute renal failure (ARF). Here we tested the effects of mycophenolate mofetil (MMF), which attenuates infiltration of lymphocytes, macrophages, and myofibroblasts, but does not suppress epithelial regeneration, on renal tissue repair. Rats treated with MMF (20 mg/kg/day) or vehicle were sacrificed at 2, 5, and 7 days after induction of ARF by injection of 5 mg/kg UA.