Diabetes induces the onset and progression of renal injury through causing hemodynamic dysregulation along with abnormal morphological and functional nephron changes. The most important event that precedes renal injury is an increase in permeability of plasma proteins such as albumin through a damaged glomerular filtration barrier resulting in excessive urinary albumin excretion (UAE). Moreover, once enhanced UAE begins, it may advance renal injury from progression of abnormal renal hemodynamics, increased glomerular basement membrane (GBM) thickness, mesangial expansion, extracellular matrix accumulation, and glomerulosclerosis to eventual end-stage renal damage. Interestingly, all these pathological changes are predominantly driven by diabetes-induced reactive oxygen species (ROS) and abnormal downstream signaling molecules. In diabetic kidney, NADPH oxidase (enzymatic) and mitochondrial electron transport chain (nonenzymatic) are the prominent sources of ROS, which are believed to cause the onset of albuminuria followed by progression to renal damage through podocyte depletion. Chronic hyperglycemia and consequent ROS production can trigger abnormal signaling pathways involving diverse signaling mediators such as transcription factors, inflammatory cytokines, chemokines, and vasoactive substances. Persistently, increased expression and activation of these signaling molecules contribute to the irreversible functional and structural changes in the kidney resulting in critically decreased glomerular filtration rate leading to eventual renal failure.

. In one group of dogs (n ϭ 10), tempol infusion alone for 30 min before NLA infusion did not cause any significant changes in renal blood flow (RBF; 5.2 Ϯ 0.4 to 5.0 Ϯ 0.4 ml ⅐ min Ϫ1 ⅐ g Ϫ1 ), glomerular filtration rate (GFR; 0.79 Ϯ 0.04 to 0.77 Ϯ 0.04 ml ⅐ min Ϫ1 ⅐ g Ϫ1 ), urine flow (V; 13.6 Ϯ 2.1 to 13.9 Ϯ 2.5 l ⅐ minInterestingly, when tempol was infused in another group of dogs (n ϭ 12) pretreated with NLA, it caused increases in V (4.4 Ϯ 0.4 to 9.7 Ϯ 1.4 l⅐min Ϫ1 ⅐g Ϫ1) and in UNaV (0.7 Ϯ 0.1 to 1.3 Ϯ 0.2 mol⅐min Ϫ1 ⅐g Ϫ1 ) without affecting RBF or GFR. Although NO inhibition caused usual qualitative responses in both groups of dogs, the antidiuretic (47 Ϯ 5 vs. 26 Ϯ 4%) and antinatriuretic (67 Ϯ 4 vs. 45 Ϯ 11%) responses to NLA were seen much less in dogs pretreated with tempol. NLA infusion alone increased urinary excretion of 8-isoprostane (13.9 Ϯ 2.7 to 22.8 Ϯ 3.6 pg ⅐ min Ϫ1 ⅐ g Ϫ1

Importance Maternal smoking during pregnancy adversely affects offspring lung development with lifelong decreases in pulmonary function and increased asthma risk. In a primate model, vitamin C blocked some of the in-utero effects of nicotine on lung development and offspring pulmonary function. Objective To determine if newborns of pregnant smokers randomized to daily vitamin C would have improved pulmonary function tests (PFTs) and decreased wheezing compared to those randomized to placebo. Design, Setting, Participants, Intervention Randomized, double-blind trial in three sites in the Pacific Northwest. Between March 2007 and January 2011, 206 pregnant smokers were recruited and 179 randomized to vitamin C (500 mg/day) versus placebo (89 to vitamin C and 90 to placebo). 159 newborns of randomized pregnant smokers (76 vitamin C treated and 83 placebo treated) and 76 of pregnant nonsmokers were studied with newborn PFTs. Follow-up assessment including wheezing was assessed through one year of age and PFTs were done at one year of age. Main Outcomes and Measures The primary outcome was measurements of newborn pulmonary function (specifically the ratio of the time to peak tidal expiratory flow to expiratory time [TPTEF:TE] and passive respiratory compliance per kilogram [Crs/kg]) within 72 hours of age. Secondary outcomes included incidence of wheezing through one year of age and PFTs at one year of age. A subgroup of pregnant smokers and nonsmokers had genotyping performed. Results Newborns of women randomized to vitamin C (n= 76) had improved pulmonary function as measured by TPTEF:TE (0.383 vs 0.345; adjusted 95% confidence interval [CI] for difference 0.011, 0.062; p =0.006) and Crs/kg (1.32 vs 1.20 mL/cm H2O/kg; 95% CI 0.02, 0.20; p =0.012) than those randomized to placebo (n=83). Offspring of women randomized to vitamin C had significantly decreased wheezing through 1 year of age (15/70 [21%] vs 31/77 [40%]; relative risk 0.56, 95% CI 0.33, 0.95; p =0.03). There were no significant differences in the one year PFTs between the vitamin C and placebo groups. The effect of maternal smoking on newborn lung function was associated with maternal genotype for the alpha 5 nicotinic receptor (rs16969968) (p value for interaction = 0.0006). Conclusion and Relevance Supplemental vitamin C to pregnant smokers improved newborn PFTs and decreased wheezing through 1 year in the offspring. Vitamin C in pregnant smokers may be an inexpensive and simple approach to decrease the effects of smoking in pregnancy on newborn pulmonary function and respiratory morbidities. Trial Registration Clinicaltrials.gov, Identifier: NCT00632476

To assess the role of superoxide (O2-) and nitric oxide (NO) interaction in mediating the renal actions of ANG II, we examined the renal responses to intra-arterial infusion of ANG II (0.5 ng x kg(-1) x min(-1)) before and during administration of a superoxide dismutase mimetic, tempol (0.5 mg x kg(-1) x min(-1)), in the presence or absence of NO synthase inhibitor, nitro-L-arginine (NLA; 50 microg x kg(-1) x min(-1)), in anesthetized dogs pretreated with enalaprilat (33 microg x kg(-1) x min(-1)). In one group of dogs (n = 7), ANG II infusion before tempol infusion caused decreases of 24 +/- 4% in renal blood flow (RBF), 55 +/- 7% in urine flow (V), and 53 +/- 8% in urinary sodium excretion (U(Na)V) with a slight decrease in glomerular filtration rate (GFR; -7.8 +/- 3.4%). Tempol infusion alone did not cause significant alterations in RBF, GFR, V, or U(Na)V; however, ANG II in the presence of tempol caused a smaller degree of decreases in RBF (-12 +/- 2%), in V (-16 +/- 5%), and in U(Na)V (-27 +/- 10%) with a slight increase in GFR (6.6 +/- 2.8%) than the responses observed before tempol. In another group of NLA-treated dogs (n = 6), tempol infusion also caused significant attenuation in the ANG II-induced responses on RBF (-13 +/- 3% vs. -22 +/- 7%), GFR (-19 +/- 5% vs. -33 +/- 3), V (-15 +/- 12% vs. -28 +/- 4%), and U(Na)V (-11 +/- 14% vs. -32 +/- 7%). These data demonstrate that renal responses to ANG II are partly mediated by O2- generation and its interaction with NO. The sodium-retaining effect of ANG II is greatly influenced by O2- generation, particularly in the condition of NO deficiency.

Graciano ML, Nishiyama A, Jackson K, Seth DM, Ortiz RM, Prieto-Carrasquero MC, Kobori H, Navar LG. Purinergic receptors contribute to early mesangial cell transformation and renal vessel hypertrophy during angiotensin II-induced hypertension. Am J Physiol Renal Physiol 294: F161-F169, 2008. First published November 7, 2007 doi:10.1152/ajprenal.00281.2007.-Chronic ANG II infusions lead to increases in intrarenal ANG II levels, hypertension, and tissue injury. Increased blood pressure also elicits increases in renal interstitial fluid (RIF) ATP concentrations that stimulate cell proliferation. We evaluated the contribution of purinergic receptor activation to ANG II-induced renal injury in rats by treating with clopidogrel, a P2Y12 receptor blocker, or with PPADS, a nonselective P2 receptor blocker. ␣-Actin expression in mesangial cells, afferent arteriolar wall thickness (AAWT), cortical cell proliferation, and macrophage infiltration were used as early markers of renal injury. Clopidogrel and PPADS did not alter blood pressure, renin or kidney ANG II content. ␣-Actin expression increased from control of 0.6 Ϯ 0.4% of mesangial area to 6.3 Ϯ 1.9% in ANG II-infused rats and this response was prevented by clopidogrel (0.4 Ϯ 0.2%) and PPADS. The increase in AAWT from 4.7 Ϯ 0.1 to 6.0 Ϯ 0.1 mm in ANG II rats was also prevented by clopidogrel (4.8 Ϯ 0.1 mm) and PPADS. ANG II infusion led to interstitial macrophage infiltration (105 Ϯ 16 vs. 62 Ϯ 4 cell/mm 2 ) and tubular proliferation (71 Ϯ 15 vs. 20 Ϯ 4 cell/mm 2 ) and these effects were prevented by clopidogrel (52 Ϯ 4 and 36 Ϯ 3 cell/mm 2 ) and PPADS. RIF ATP levels were higher in ANG IIinfused rats than in control rats (11.8 Ϯ 1.9 vs. 5.6 Ϯ 0.6 nmol/l, P Ͻ 0.05). The results suggest that activation of vascular and glomerular purinergic P2 receptors may contribute to the mesangial cell transformation, renal inflammation, and vascular hypertrophy observed in ANG II-dependent hypertension. extracellular ATP; renal inflammation; vascular hypertrophy ANG II-DEPENDENT HYPERTENSION is characterized by increases in intrarenal ANG II content and renal functional impairment with variable degrees of injury to several organs and tissues, including heart, kidney, and blood vessels (7,16,23,25,31,38,42,47,50). The ANG II-associated tissue injury occurs more consistently in a setting of elevated arterial pressure suggesting that factors existing in hypertensive, but not normotensive, conditions may be contributing to the damage observed during hypertension caused by chronic ANG II infusions. While mechanical forces caused by the elevated arterial pressures directly cause baromechanical trauma (1), elevated arterial pressure may independently activate paracrine systems that contribute to the ANG II-mediated vascular and tissue injury (38, 47). Various proliferative agents are capable of inducing vascular hypertrophy, mesangial activation, or cortical renal injury (38). These independent factors, directly stimulated by the elevated arterial pressure, may synergize with the eleva...

Vascular heme oxygenase (HO) metabolizes heme to form carbon monoxide (CO). Increased heme-derived CO inhibits nitric oxide synthase and can contribute to hypertension via endothelial dysfunction in Dahl salt-sensitive rats. Obese Zucker rats (ZR) are models of metabolic syndrome. This study tests the hypothesis that endogenous CO formation is increased and contributes to hypertension and endothelial dysfunction in obese ZR. Awake obese ZR showed increased respiratory CO excretion, which was lowered by HO inhibitor administration [zinc deuteroporphyrin 2,4-bis glycol (ZnDPBG) 25 mol ⅐ kg Ϫ1 ⅐ 24 h Ϫ1 ip]. In awake obese ZR, chronically instrumented with femoral arterial catheters, blood pressure was elevated but was decreased by the HO inhibitor ZnDPBG. Body weight, blood glucose, glycated hemoglobin, plasma insulin, total and LDL cholesterol, oxidized LDL, and triglyceride levels were elevated in obese ZR, and, except for LDL cholesterol, were unchanged by HO inhibition. Total HO-1 protein levels were not different between lean and obese ZR aortas. In vitro experiments used isolated skeletal muscle arterioles with constant pressure and no flow, or constant midpoint, but altered endpoint pressures to establish graded levels of luminal flow. In obese ZR arterioles, responses to ACh and flow were attenuated. Acute in vitro pretreatment with an HO inhibitor, chromium mesoporphyrin, enhanced ACh and flow-induced dilation and abolished the differences between groups. Furthermore, exogenous CO prevented the restoration of flow-induced dilation by the HO inhibitor in obese ZR arterioles. These results suggest that HO-derived CO production is increased and promotes hypertension and arteriolar endothelial dysfunction in obese ZR with metabolic syndrome independent of affecting metabolic parameters. heme oxygenase; blood pressure; arterioles; vascular tone regulation METABOLIC SYNDROME IS CHARACTERIZED by upper body obesity, insulin resistance, hyperlipidemia, and hypertension, and it represents a major and growing health problem in the United States (11). Endothelial dysfunction due to impaired nitric oxide function, is a key feature promoting microvascular disease in resistance vessels, which contributes to hypertension during obesity (43) and metabolic syndrome. The obese Zucker rat (ZR) is a well established genetic model of obesity (58). Because of a nonfunctional leptin receptor gene (19) and the consequent hyperphagia, these animals develop obesity and metabolic syndrome, including insulin resistance (29), hyperlipidemia (29), and hypertension (13). Previous studies have shown impaired endothelium-derived nitric oxide-dependent vasodilation in various vascular beds of obese ZR (12,13,33,41), including skeletal muscle resistance vessels (12, 13).Metabolic syndrome represents a major cardiovascular risk factor, which is further enhanced by the increased chance of type 2 diabetes development (11). It is known that patients with type 2 diabetes show increased respiratory carbon monoxide (CO) levels (39). Although eleva...

IMPORTANCE Maternal smoking during pregnancy adversely affects offspring lung development, with lifelong decreases in pulmonary function and increased asthma risk. In a primate model, vitamin C blocked some of the in-utero effects of nicotine on lung development and offspring pulmonary function. OBJECTIVETo determine if newborns of pregnant smokers randomized to receive daily vitamin C would have improved results of pulmonary function tests (PFTs) and decreased wheezing compared with those randomized to placebo. DESIGN, SETTING, AND PARTICIPANTS Randomized, double-blind trial conducted in 3 sites in the Pacific Northwest between March 2007 and January 2011. One hundred fifty-nine newborns of randomized pregnant smokers (76 vitamin C treated and 83 placebo treated) and 76 newborns of pregnant nonsmokers were studied with newborn PFTs. Follow-up assessment including wheezing was assessed through age 1 year, and PFTs were performed at age 1 year.INTERVENTIONS Pregnant women were randomized to receive vitamin C (500 mg/d) (n = 89) or placebo (n = 90). MAIN OUTCOMES AND MEASURESThe primary outcome was measurement of newborn pulmonary function (ratio of the time to peak tidal expiratory flow to expiratory time [TPTEF:TE] and passive respiratory compliance per kilogram [Crs/kg]) within 72 hours of age. Secondary outcomes included incidence of wheezing through age 1 year and PFT results at age 1 year. A subgroup of pregnant smokers and nonsmokers had genotyping performed. RESULTS Newborns of women randomized to vitamin C (n = 76), compared with those randomized to placebo (n = 83), had improved pulmonary function as measured by TPTEF:TE (0.383 vs 0.345 [adjusted 95% CI for difference, 0.011-0.062]; P = .006) and Crs/kg (1.32 vs 1.20 mL/cm H 2 O/kg [95% CI, 0.02-0.20]; P = .01). Offspring of women randomized to vitamin C had significantly decreased wheezing through age 1 year (15/70 [21%] vs 31/77 [40%]; relative risk, 0.56 [95% CI, 0.33-0.95]; P = .03). There were no significant differences in the 1-year PFT results between the vitamin C and placebo groups. The effect of maternal smoking on newborn lung function was associated with maternal genotype for the α5 nicotinic receptor (rs16969968) (P < .001 for interaction). CONCLUSIONS AND RELEVANCE Supplemental vitamin C taken by pregnant smokers improved newborn PFT results and decreased wheezing through 1 year in the offspring. Vitamin C in pregnant smokers may be an inexpensive and simple approach to decrease the effects of smoking in pregnancy on newborn pulmonary function and respiratory morbidities.

These data suggest that the vagolytic effect of MEAP involves the activation of delta opiate receptors within the sinoatrial node.