Urinary fatty acids and liver-type fatty acid binding protein in diabetic nephropathy.

BACKGROUND: The aims of this clinical study were to investigate the associations of urinary free fatty acid (FFA) levels with tubulointerstitial damage, and to determine the clinical significance of urinary liver-type fatty acid binding protein (L-FABP) in diabetic nephropathy. METHODS: Fifteen patients with nephrotic syndrome due to diabetic nephropathy and 12 patients with minimal-change nephrotic syndrome (MCNS) were studied. Urinary and serum FFA concentrations (palmitic, oleic, linoleic, and arachidonic acids) were measured by gas chromatography, and urinary L-FABP levels were quantified using an ELISA technique. Tubulointerstitial damage was assessed using renal biopsy specimens. RESULTS: The levels of urinary linoleic and arachidonic acids were significantly elevated in diabetic nephropathy compared to MCNS patients, though serum FFA levels were lower in diabetic nephropathy than MCNS patients. The degree of tubulointerstitial damage was significantly severer in the patients with diabetic nephropathy than MCNS. Urinary L-FABP and 8-OHdG (8-hydroxydeoxyguanosine) concentrations were significantly higher in the diabetic nephropathy subjects. CONCLUSION: Elevated urinary excretion of FFA may be a reflection of FFA overload in the proximal tubules, and FFA may be an important promoter of tubulointerstitial damage in diabetic nephropathy patients. Urinary L-FABP levels may reflect the stress induced by FFA to the proximal tubules, leading to severe tubulointerstitial damage.

Estrogen and environmental estrogenic chemicals exert developmental effects on rat hypothalamic neurons and glias.

We investigated effects of 17beta-estradiol (E(2)) and endocrine disrupters, nonylphenol (NP) and bisphenol-A (BPA), focusing on the neuronal development in cultures of fetal rat hypothalamic cells. We applied different concentrations of E(2), NP or BPA to the cultured hypothalamic cells and observed their effects on dendritic and synaptic development by immunocytochemistry using anti-microtubule associated protein-2 (MAP2) and anti-synapsin I antibodies, respectively. Administration of E(2) for 7 days affected MAP2-positive area as well as synapsin I-positive area. NP and BPA also influenced neuronal developments. The significant increase both in MAP2- and synapsin I-positive areas was observed at 10 and/or 100 nM of them, while 1 microM of them reduced the positive areas. Synaptic densities calculated from synapsin I-positive area/MAP2-positive area were not constant among different doses of three chemicals, but increased at 10 and/or 100 nM and decreased at 1 microM. Furthermore, immunostaining of NP-treated cells with the antibody against glial fibrillary acidic protein (GFAP) revealed that glial development was similarly influenced by NP. Therefore, the present results demonstrated that not only E(2) but also the environmental estrogenic chemicals, NP and BPA, affect development of fetal rat hypothalamic cells in vitro.

Contribution of mitogen-activated protein kinases to NMDA-induced neurotoxicity in the rat retina.

We examined the contributions of the mitogen-activated protein kinases (MAPKs) family [extracellular signal-regulated kinase (ERK), p38 kinase (p38), and c-Jun N-terminal kinase (JNK)] to N-methyl-D-aspartate (NMDA)-induced neurotoxicity in the rat retina. Detection of apoptotic cell death in the retinal ganglion cell layer (RGCL) and the inner nuclear layer (INL) by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) staining began 6 h after intravitreal NMDA (100 nmol) injection and continued to increase thereafter. Western blot analysis showed that phosphorylated MAPKs (p-MAPKs) were expressed in the retina following a temporal manner: maximal expression of phosphorylated ERK (p-ERK) at 1 h, maximal expression of phosphorylated p38 (p-p38) at 6 h, and beginning of phosphorylated JNK (p-JNK) significant increase at 6 h after injection. An immunohistochemical/TUNEL co-localization study showed that p-JNK- and p-p38-positive cells in the RGCL were frequently TUNEL-positive, whereas few p-ERK-positive cells were TUNEL-positive. Moreover, co-injection of inhibitors for JNK (0.2 nmol SP600125) and/or p38 (2.0 nmol SB203580) with NMDA was effective in ameliorating NMDA-induced apoptotic cell loss in the RGCL 12 h after injection, as shown by TUNEL-positive cell counts. These inhibitors also protected the inner retina as shown by morphometric studies such as cell counts in the RGCL and measurement of the IPL thickness 7 days after injection. On the other hand, an ERK inhibitor (2.0 nmol U0126) did not suppress NMDA-induced cell death in the RGCL nor thinning of the IPL. These findings suggest that JNK and p38 are proapoptotic in NMDA-induced cell death in the RGCL, but not ERK.