Pharmacologic control of angiotensin II ameliorates renal disease while reducing renal TGF-beta in experimental mesangioproliferative glomerulonephritis

We evaluated the effect of blocking angiotensin II (AngII) on the development of proteinuria and glomerular injury in antithymocyte serum (ATS) glomerulonephritis. Disease was induced in Sprague-Dawley rats by a single intravenous injection of rabbit ATS. Three groups of rats were considered: group 1 (n = 13), ATS rats with no therapy; group 2 (n = 13), ATS rats treated with angiotensin-converting enzyme inhibitor (40 mg/L lisinopril in the drinking water); and group 3 (n = 13), ATS rats treated with AngII receptor antagonist (50 mg/L L-158,809 in the drinking water). Treatment started 3 hours after ATS injection and lasted 4 days. An additional group of control rats (group 4, n = 13) received preimmune serum. At day 4, ATS rats developed proteinuria (46+/-5 mg/d v control 12+/-1 mg/d; P < 0.01), which was prevented by both lisinopril and L-158,809 (14+/-0.2 mg/d and 15+/-1.6 mg/d, respectively, P < 0.01 v ATS). Systolic blood pressure was comparable in ATS rats and in controls (119+/-4 mm Hg v 120+/-2 mm Hg). Systolic blood pressure values were significantly decreased after either lisinopril or L-158,809 (104+/-3 mm Hg and 101+/-5 mm Hg, respectively; P < 0.01 v ATS). Serum creatinine levels were similar in all groups. Quantitation of proliferating cells and macrophages by analysis of proliferating cell nuclear antigen-positive and ED1-positive cells/glomerular cross-section showed a marked increase in proliferating cell nuclear antigen-positive cells in glomeruli of ATS rats over controls (12.6+/-0.5 cells/glomerular cross-section v 1.9+/-0.2 cells/glomerular cross-section; P < 0.01), which was significantly (P < 0.01) prevented by both treatments (lisinopril, 5.7+/-1.0 cells/glomerular cross-section; L-158,809, 4.8+/-1.5 cells/glomerular cross-section). The increase in ED1-positive cells (10+/-0.7 cells/glomerular cross-section v controls, 1.8+/-0.2 cells/glomerular cross-section; P < 0.01) was also significantly (P < 0.01) reduced by lisinopril and L-158,809 (4.1+/-0.7 cells/glomerular cross-sections and 2.6+/-0.6 cells/glomerular cross-section, respectively). Blocking of AngII activity prevented almost completely the formation of microaneurysms in ATS rats (percent of glomeruli with microaneurysms: ATS, 11.5%+/-3.5%; ATS + lisinopril, 0.4%+/-0.2%; ATS + L-158,809, 0.8%+/-0.8%; controls, 0%). Because AngII is a potent inducer of renal transforming growth factor-beta (TGF-beta), a cytokine involved in the regulation of cell proliferation, matrix deposition, and monocyte migration (which is overexpressed in the kidney of ATS rats), we then evaluated the effect of AngII inhibitors on renal gene expression of TGF-beta1 and on urinary TGF-beta1. TGF-beta1 mRNA levels in kidneys of ATS rats were 3.6-fold higher than those of controls and were reduced by 46% and 32% after treatment with lisinopril and L-158,809, respectively. Urinary TGF-beta1 excretion increased in ATS (37.3+/-6.0 ng/d v controls, 13.8+/-3.4 ng/d; P< 0.01) but was normalized by lisinopril and L-158,809 (7.6+/-1.9 ng/d and 6.4+/-0.4 ng/d, respectively; P < 0.01). Thus, in ATS, blocking AngII synthesis prevents proteinuria and reduces glomerular cell proliferation and inflammatory cell infiltration, possibly by reducing excessive renal TGF-beta synthesis. These findings may be relevant for future strategies in the treatment of human mesangioproliferative glomerulonephritis.     

胃肠道左旋精氨酸营养干预对严重烧伤患者休克期复苏的影响

目的观察严重烧伤患者休克期经胃肠道给予左旋(L)精氨酸对休克复苏的影响,探讨其机制。方法选取烧伤面积≥30%TBSA的患者20例,并随机分为:L-精氨酸组,伤后24h内开始从鼻肠管给予L-精氨酸;对照组,伤后24h内开始从鼻肠管给予50g/L葡萄糖盐水500ml/d,连续4d,每组10例。在伤后1、2、3、4d分别抽取两组患者静脉血,检测其血清超氧化物歧化酶(SOD)活性及丙二醛(MDA)和一氧化氮(NO)含量,并抽取患者动脉血检测其乳酸含量。结果L-精氨酸组患者SOD活性在伤后呈上升趋势,于伤后4d达峰值(68±23)U/ml,与对照组(31±9)U/ml比较,差异有统计学意义(P<0·01)。两组患者伤后MDA、NO含量均呈下降趋势,伤后2dL-精氨酸组NO[(50±14)μmol/L]下降最明显,与对照组(78±22)μmol/L比较,差异有统计学意义(P<0.01)。伤后4d两组患者MDA下降最明显[(3.4±0.8)、(3.5±1.3)μmol/L],L-精氨酸组血乳酸含量在伤后2、3d显著低于对照组(P<0.05或0.01)。结论严重烧伤患者休克期经胃肠道给予L-精氨酸可抑制其体内NO含量过度升高,使血乳酸含量降低,血清SOD活性增加,改善组织脏器血流灌注及氧合状态,减轻缺血再灌注损伤,有利于预防隐性休克的发生或减轻其损害。     

Increased oxygen radical and eicosanoid formation in immune-mediated mesangial cell injury.

To evaluate whether monocytes/macrophages derived from glomeruli could be a source of increased eicosanoid and free oxygen radical formation in glomerular disease, monocytes/macrophage (M/M) were isolated from nephritic glomeruli and their in vitro generation of eicosanoids and superoxides were measured. Glomerular immune injury was induced by i.v. injection of a rabbit-anti-rat thymocyte antiserum (ATS). Kidneys were removed two, five, and 24 hours, and three and eight days after ATS. Adhesive glomerular macrophages were obtained by isolation of glomeruli, enzymatic digestion and incubation of the single cell suspensions in culture dishes. O2-production was evaluated by superoxide dismutase (SOD)-inhibitable reduction of ferricytochrome C; PGE2 and TxB2 release was assessed by direct RIA. Glomerular macrophage infiltration was maximal 24 hours after intravenous antibody (35.9 +/- 5.1 M/M per glomerulus). In vitro production of superoxide was significantly enhanced (P less than 0.001) five hours after ATS administration (51.6 +/- 4.4 nmol O2/10(6) MM/hr), when compared with M/M from controls (30.4 +/- 2.0 nmol O2/10(6) MM/hr). TxB2 formation of glomerular M/M was increased (P less than 0.001) two hours and five hours after ATS administration (1056 +/- 75 and 1182 +/- 112 pg TxB2/10(6) MM/hr) compared with controls (390 +/- 34 pg TxB2/10(6) MM/hr). PGE2 synthesis, however, was decreased (P less than 0.01) at five hours after ATS (629 +/- 43 pg PGE2/10(6) MM/hr) compared with controls (950 +/- 125 pg PGE2/10(6) MM/hr). Furthermore, there was release of leukotriene B4 (LTB4) in monocytes of nephritic glomeruli five hours after ATS administration.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of supplemental ornithine on wound healing

BACKGROUND: Supplemental arginine has been shown to enhance wound healing, in particular collagen synthesis. Ornithine is the main metabolite of arginine in the urea cycle and shares many of the biopharmacologic effects of arginine. The present study examines the effect of ornithine supplementation on wound healing and attempts to describe its possible mechanism. METHODS: Wild type (WT) and iNOS knockout (KO) mice were randomized to receive either normal chow and tap water or chow and water each supplemented with 0.5% ornithine (w/w). All animals underwent a midline dorsal skin incision with implantation of polyvinyl alcohol sponges into subcutaneous pockets. On postoperative day 14 the animals were sacrificed. The dorsal wound was harvested for breaking strength determination while the wound sponges were assayed for hydroxyproline content, total wound fluid amino acid, and nitrite/nitrate (NOx) concentration. RESULTS: Dietary ornithine supplementation enhanced wound breaking strength and collagen deposition in both WT and KO mice. This was accompanied by increased wound fluid proline and ornithine levels but not arginine, citrulline, or NOx levels. CONCLUSIONS: The results from this study demonstrate that ornithine supplementation enhances wound healing in both WT and KO mice. This suggests that ornithine's effect on wound healing is independent of the iNOS pathway.     

早期肠内营养与精氨酸改善烧伤后肝脏白蛋白合成的实验研究

目的　观察含精氨酸的早期肠内营养能否改善烧伤后大鼠肝脏白蛋白的合成及其对一些细胞因子基因表达的影响。　方法　应用反转录聚合酶链式反应 (RT -PCR)和毛细管电泳半定量检测白蛋白等的mRNA表达 ,观察富含精氨酸早期肠内营养组 (AEF组 )及单纯早期肠内营养组(EF)大鼠在烧伤后第 1、3、6、9天肝脏白蛋白、肿瘤坏死因子α(TNFα)、白细胞介素 1α(IL - 1α)、白细胞介素 6受体 (IL - 6R)、诱导型一氧化氮合成酶 (iNOS)的mRNA表达及血浆白蛋白的变化。　结果　两组大鼠烧伤后第 1天白蛋白mRNA水平均明显降低 ,此后逐渐恢复。在烧伤后第 3天和第 9天 ,AEF组白蛋白mRNA明显高于EF组 [( 1812± 41)vs( 1417± 43) ,P <0 .0 1]。在烧伤后第 1天TNFα、IL - 1α、IL - 6R、iNOS的mRNA表达均有显著的升高。此后各细胞因子基因表达呈下降趋势。在烧伤后第 6天 ,AEF组TNFα的mRNA明显低于EF组。在烧伤后第 3天和第 6天 ,AEF组IL - 1αmRNA明显低于EF组。在烧伤后第 9天 ,AEF组IL - 6RmRNA明显低于EF组。两组在烧伤后iNOSmRNART-PCR产物无显著差别。　结论　富含精氨酸的早期肠内营养可减少烧伤后TNFα、IL - 1α、IL - 6R的基因表达 ,进一步改善肝脏白蛋白合成 ,不会导致iNOS的过度表达     

Nitric oxide production is more prominent in off-pump than in on-pump coronary artery bypass surgery

The aim of our study was to elucidate the extent to which cardiopulmonary bypass contributes to endogenous nitric oxide (NO) production in patients undergoing coronary artery bypass grafts (CABG). One-hundred-and-sixteen patients undergoing elective CABG with (on-pump, n=66) and without cardiopulmonary bypass (off-pump, n=50) were included. Urinary nitrite/nitrate (NOx) excretion was measured as an index of endogenous NO production during the first two postoperative days. Haemodynamic profiles, serum CK-MB and C-reactive protein (CRP) concentrations were measured after the operation. There was no significant difference in urinary NOx/creatinine (Cr) excretion on day one post CABG. The mean urinary NOx/Cr excretion ratio significantly (P < 0.01) decreased from days one to two in the on-pump group, but not in the off-pump group. The mean urinary NOx/Cr excretion ratio was significantly (P < 0.01) higher in the off-pump group (0.51 +/- 0.26 micromol/mg) than in the on-pump group (0.38 +/- 0.20 micromol/mg) on day two. The mean serum CRP concentration was also significantly (P < 0.01) higher in the off-pump group than in the on-pump group on day two. There was no significant difference in the mean cardiac index or the mean systemic vascular resistance index between the two groups after surgery. The mean serum CK-MB concentration was significantly (P < 0.05) lower in the off-pump group than in the on-pump group on days one and two. These findings suggest that endogenous NO production is stimulated by a surgical inflammatory response and that the cardiopulmonary bypass procedure per se is not the inciting stimulus for NO production in patients undergoing CABG.     

Selective inducible nitric oxide synthase (iNOS) inhibition attenuates remote acute lung injury in a model of ruptured abdominal aortic aneurysm

OBJECTIVE: Abdominal aortic aneurysm rupture is associated with a systemic inflammatory response syndrome and acute lung injury. Using a selective inducible nitric oxide synthase (iNOS) inhibitor, N(6)-(iminoethyl)-lysine (L-NIL), we explored the role of iNOS in the early pro-inflammatory signaling and acute lung injury in experimental abdominal aortic aneurysm rupture. MATERIALS AND METHODS: Anesthetized rats were randomized to sham control or shock and clamp (s + c) groups, which underwent one hour of hemorrhagic shock, followed by 45 minutes of supramesenteric aortic clamping, and then two hours resuscitated reperfusion. Animals in s + c were randomized to receive intravenous L-NIL at 50 microg/kg/h or saline at the start of reperfusion. Pulmonary permeability to (125)I-labeled albumin, myeloperoxidase (MPO) activity, cytokine levels, and semi-quantitative RT-PCR for mRNA were indicators of microvascular permeability, leuco-sequestration, and pro-inflammatory signaling, respectively. RESULTS: Lung permeability index were significantly increased in s + c compared to sham (4.43 +/- 0.96 versus 1.30 +/- 0.17, P < 0.01), and attenuated by L-NIL treatment (2.14 +/- 0.70, P < 0.05). Lung tissue MPO activity was significantly increased in s + c compared to sham (2.80 +/- 0.32 versus 1.03 +/- 0.29, P < 0.002), and attenuated by L-NIL treatment (1.50 +/- 0.20, P < 0.007). Lung tissue iNOS activity was significantly increased in s + c compared to sham animals (P < 0.05), and attenuated by L-NIL treatment (P < 0.05). Lung tissue iNOS mRNA was upregulated 8-fold in s + c compared to sham (P < 0.05). Data represents mean +/- standard error mean, comparisons with ANOVA. CONCLUSIONS: These data suggest that in our model of ruptured abdominal aortic aneurysm iNOS plays a crucial role in reperfusion lung injury. Selective inhibition of iNOS during early reperfusion prevents neutrophil mediated acute lung injury.     

Nitric oxide modulates fracture healing.

The role of the messenger molecule nitric oxide has not been evaluated in fracture healing. NO is synthesized by three kinds of nitric oxide synthase (NOS): inducible NOS (iNOS), endothelial (eNOS), and neuronal (bNOS). We evaluated the role of these enzymes in a rat femur fracture-healing model. There was no messenger RNA (mRNA) expression, immunoreactivity, or enzymatic activity for NOS in unfractured femoral cortex. After fracture, however, mRNA, protein, and enzymatic activity for iNOS were identified in the healing rat femoral fracture callus, with maximum activity on day 15. The mRNA expression for eNOS and bNOS was induced slightly later than for iNOS, consistent with a temporal increase in calcium-dependent NOS activity that gradually increased up to day 30. mRNA expression for the three NOS isoforms also was found in six of six human fracture callus samples. To study the effect of suppression of NO synthesis on fracture healing, an experimental group of rats was fed an NOS inhibitor, L-nitroso-arginine methyl ester (L-NAME), and the control group was fed its inactive enantiomer, D-nitroso-arginine methyl ester (D-NAME). An 18% (p < or = 0.01) decrease in cross-sectional area and a 45% (p < or = 0.05) decrease in failure load were observed in the NOS-inhibited group on day 24 after fracture. Furthermore, the effect of NO supplementation to fracture healing was studied by delivering NO to the fracture site using carboxybutyl chitosan NONOate locally. On day 17 after fracture, there was a 30% (p < or = 0.05) increase in cross-sectional area in the NO-donor group compared with the NOS inhibition group. These results show for the first time that NO is expressed during fracture healing in rats and in humans, that suppression of NOS impairs fracture healing, and that supplementation of NO can reverse the inhibition of healing produced by NOS inhibitors.     

Effects of in vivo myocardial ischemia and reperfusion on interstitial nitric oxide metabolites

BACKGROUND: There have been numerous studies examining the role of nitric oxide (NO) in myocardial ischemia-reperfusion injury; however, few studies have included measurements of NO or related reactive nitrogen species. The purpose of this study was to determine the effects of in vivo regional myocardial ischemia on interstitial fluid (ISF) reactive nitrogen species. METHODS: Open chest pigs were submitted to one of three protocols: (1) 15 minutes coronary occlusion and 2 hours reperfusion, (2) 60 minutes coronary occlusion and 2 hours reperfusion, or (3) two-cycle ischemic preconditioning (IPC) followed by prolonged ischemia and 2 hours reperfusion. The stable NO metabolites, nitrite plus nitrate (NOx), in cardiac microdialysis samples were measured by ozone chemiluminescence. RESULTS: NOx concentration decreased 40% +/- 6% (p < 0.05) during brief ischemia but returned to baseline during reperfusion. Dialysate NOx levels decreased further after 60 minutes ischemia (60% +/- 3% of baseline, p < 0.01) but reperfusion dialysate NOx concentration increased 34% +/- 9% above baseline (p < 0.05). Preconditioning did not increase dialysate NOx but did accelerate the ischemia-induced decrease in NOx levels (p < 0.05). Reperfusion NOx levels in preconditioned pigs were significantly lower than in nonpreconditioned pigs (p < 0.05). CONCLUSIONS: These results suggest that ischemia is associated with decreased ISF NOx concentration. Reperfusion NOx levels are increased after prolonged ischemia, an effect that is significantly blunted by ischemic preconditioning.     

Inducible nitric oxide synthase has divergent effects on vascular and metabolic function in obesity

Previous studies have suggested an involvement of inducible nitric oxide synthase (iNOS) in obesity, but the relation, if any, between this and mechanisms underlying endothelial dysfunction in obesity is unknown. We studied mice fed an obesogenic high-fat or standard diet for up to 8 weeks. Obesity was associated with elevated blood pressure; resistance to the glucoregulatory actions of insulin; resistance to the vascular actions of insulin, assessed as the reduction in phenylephrine constrictor response of aortic rings after insulin preincubation (lean -21.7 +/- 11.5 vs. obese 18.2 +/- 15.5%; P < 0.05); and evidence of reactive oxygen species (ROS)-dependent vasodilatation in response to acetylcholine in aortic rings (change in maximal relaxation to acetylcholine after exposure to catalase: lean -2.1 +/- 6.0 vs. obese -15.0 +/- 3.8%; P = 0.04). Obese mice had increased expression of iNOS in aorta, with evidence of increased vascular NO production, assessed as the increase in maximal constriction to phenylephrine after iNOS inhibition with 1400W (lean -3.5 +/- 9.1 vs. obese 42.1 +/- 11.2%; P < 0.001). To further address the role of iNOS in obesity-induced vascular and metabolic dysfunction, we studied the effect of a high-fat diet in iNOS knockout mice (iNOS KO). Obese iNOS KO mice were protected against the development of resistance to insulin's glucoregulatory and vascular effects (insulin-dependent reduction in maximal phenylephrine response: obese wild-type 11.2 +/- 15.0 vs. obese iNOS KO -20.0 +/- 7.7%; P = 0.02). However, obese iNOS KO mice remained hypertensive (124.0 +/- 0.7 vs. 114.9 +/- 0.5 mmHg; P < 0.01) and had evidence of increased vascular ROS production. Although these data support iNOS as a target to protect against the adverse effects of obesity on glucoregulation and vascular insulin resistance, iNOS inhibition does not prevent the development of raised blood pressure or oxidative stress.     

Effects of estrogen on nitric oxide synthase expression in rat aorta allograft and smooth muscle cells.

BACKGROUND: We find that chronic estradiol treatment inhibits the development of transplant arteriosclerosis (TA). The mechanism of this inhibition remains unclear. The objective of this study is to investigate in a non-cyclosporin-requiring TA model whether estradiol-17beta treatment modulates the expression of both endothelial nitric oxide synthase (ecNOS) and inducible nitric oxide synthase (iNOS) in the early phase following transplantation. METHODS: Orthotopic abdominal aorta allograft transplantation was performed in male rats using Brown-Norway rats as donors and Lewis rats as recipients. The recipients (n = 50) were treated with estradiol 20 microg/kg/day or placebo by osmotic minipump from 2 days prior to surgery until sacrifice on post-operative days 1, 3, 7, 14, and 21. The allografts were harvested and cross-sections of the vascular tissues were used for immunohistochemical staining of ecNOS and iNOS. The effects of estradiol on cytokine-induced (tumor necrosis factor-alpha and interleukin-1 beta iNOS protein and messenger RNA (mRNA) expression were also evaluated on rat aorta smooth muscle cells by Western blotting and RT-PCR in vitro, respectively. RESULTS: The expression of ecNOS and iNOS was graded semiquantitatively from 0 to +3. Estrogen elevates ecNOS expression in the intima in the early phase following transplantation, 0.85 +/- 0.14 (day 7) and 1.08 +/- 0.11 (day 14) vs 1.53 +/- 0.25 (day 7) and 1.60 +/- 0.17 (day 14) for placebo and estradiol treated groups respectively, p < 0.01. Estrogen suppresses iNOS expression in neointima (0.67 +/- 0.17 vs 0.24 +/- 0.04, p < 0.01, day 14), media (1.03 +/- 0.15 vs 0.4 +/- 0.09, p < 0.01, day 7), and adventitia (1.55 +/- 0.12 vs 1.02 +/- 0.10, p < 0.05, day 14) in the same phase. Estradiol treatment inhibits cytokine-induced iNOS mRNA expression in cultured smooth muscle cells. CONCLUSIONS: Chronic estrogen treatment modulates both ecNOS and iNOS expression in the early phase following transplantation. This is associated with the estrogen-protective effects on TA.     

Imbalance between nitric oxide generation and oxidative stress in patients with peripheral arterial disease: effect of an antioxidant treatment

BACKGROUND: Nitric oxide (NO), a potent vasodilator produced by endothelial cells, is reduced in patients with peripheral arterial disease (PAD), but the mechanism has not been fully elucidated. Because NO is rapidly inactivated by superoxide anion, we speculated that enhanced oxidative stress could lower NO generation. The aim of our study was to investigate if an imbalance between oxidative stress and NO does exist in patients with PAD and if an increase of NO formation could be achieved by an antioxidant treatment. METHODS: In a first study, serum levels of nitrite and nitrate (NOx), markers of NO generation, and 8-hydroxy-2-deoxyguanosine (8-OHdG), a marker of oxidative stress and maximal walking distance (MWD), were measured in 40 PAD patients and 40 controls. In a second study, 10 PAD patients were randomly allocated in a crossover design to intravenous propionyl-L-carnitine (6 g/day) or placebo for 7 days, with a washout of 30 days between the two phases of the trial. Serum levels of NOx and 8-OHdG were measured before and after the study. RESULTS: Compared with controls, serum levels of 8-OHdG (mean +/- SD) were significantly increased in PAD patients (4.4 +/- 3.1 ng/mL vs 2.4 +/- 1.2 ng/mL; P < .001), and serum levels of NOx were significantly decreased (11.6 +/- 6 microM vs 17 +/- 6.1 microM; P < .001). Levels of 8-OHdG and NOx were inversely correlated (r = -0.879; P < .001). Serum levels 8-OHdG were inversely correlated with MWD (r = -0.48, P = .002). The interventional trial showed no changes in the patients given placebo. Patients treated with propionyl-L-carnitine showed a significant increase of MWD from 101 +/- 31 meters to 129 +/- 35 meters (P = .007) and in NOx from 14.5 +/- 4.5 microM to 17.1 +/- 3.8 microM (P = .007). A significant decrease of 8-OHdG from 3.6 +/- 1.1 ng/mL to 2.6 +/- 1 ng/mL was also found (P = .005.) CONCLUSIONS: This study suggests that in PAD patients, the reduction of NO generation could be dependent upon enhanced oxidative stress.     

Angiotensin II infusion increases plasma erythropoietin levels via an angiotensin II type 1 receptor-dependent pathway.

BACKGROUND: Angiotensin-converting enzyme inhibitors (ACEIs) have been shown to lower hematocrit and erythropoietin (EPO), but a direct link between angiotensin II (Ang II) and EPO in humans has not been shown. METHODS: Placebo or Ang II was infused for six hours in nine healthy male volunteers with and without blockade of the Ang II subtype 1 receptor (AT1R). EPO concentrations were measured 3, 6, 12, and 24 hours after the start of the infusion. RESULTS: Ang II raised the mean arterial pressure by about 20 mm Hg. Consistent with the known diurnal variation, EPO levels rose significantly (P < or = 0.02) during the day in all groups. During Ang II infusion, EPO levels rose to significantly higher levels after 6 and 12 hours compared with placebo [9.9 +/- 3.5 vs. 7.2 +/- 3.1 mU/mL (3 h, P = NS); 16.9 +/- 4.5 vs. 8.8 +/- 3.7 mU/mL (6 h, P = 0.01); 17.0 +/- 8.6 vs. 11.1 +/- 4.7 mU/mL (12 h, P = 0.01)] and returned to baseline after 24 hours (7.9 +/- 3.8 vs. 10.6 +/- 8.6 mU/mL, P = NS). With AT1R blockade, blood pressure remained normal during Ang II infusion, and EPO levels were never significantly different from placebo [6.8 +/- 4.8, 10.5 +/- 5.6, 13.1 +/- 9.0, and 12.4 +/- 10.1 mU/mL at 3, 6, 12, and 24 h after infusion, respectively, P = NS]. CONCLUSIONS: Ang II increases EPO levels in humans. This increase requires the participation of AT1R.     

L-精氨酸对内毒素诱导大鼠肺组织线粒体损伤的影响

目的 评价L精氨酸(L-Arg)对内毒素(LPS)诱导大鼠肺组织线粒体损伤的影响,探讨其减轻内毒素性急性肺损伤的作用机制.方法 雄性SD大鼠24只,随机分为3组(n=8):假手术组(S组)、LPS组和L-Arg组.LPS组和L-Arg组静脉注射LPS 5 mg/kg(用生理盐水稀释至1 ml/kg),S组给予生理盐水1 ml/kg,3 h后L-Arg组腹腔注射L-Arg 500 mg/kg(用生理盐水稀释至1 ml/kg),S组和Au组给予生理盐水1 ml/kg.注射L-Arg或生理盐水后3 h.取肺组织.提取线粒体,测定超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、ATPase、丙二醛(MDA)、一氧化氮合酶(NOS)、诱生型一氧化氮合酶(iNOS)、结构型一氧化氮合酶(cNOS)、一氧化氮(NO)的水平、线粒体膜肿胀度、线粒体活力和线粒体膜流动性;电镜观察肺组织超微结构.结果 与S组比较,LPS组SOD、GSH-Px、ATPase、线粒体活力和线粒体膜流动性降低,MDA、NOS、iNOS、NO及线粒体膜肿胀度升高(P<0.01);与LPs组比较,L-Arg组SOD、GSH.Px、ATPase、线粒体活力和线粒体膜流动性升高,MDA含量和线粒体膜肿胀度降低(P<0.05).L-Ars组细胞肿胀、线粒体肿胀和空泡化的程度轻于LPS组.结论 L-Arg可减轻LPS诱导大鼠肺组织线粒体损伤,其机制与增强抗过氧化能力有关.     

左心辅助对犬内皮素、肾素及前列腺素的影响

目的　了解左心辅助期间犬体内内皮素 (ET)、肾素及前列腺素浓度的变化。方法　采用自身配对设计 ,对 8条犬行左心辅助 9h ,用放射免疫分析方法测定左心辅助前 (对照组 )与辅助 3、6、9h时血浆ET、肾素及 6 酮 前列腺素F1 α(6 k PGF1 α)浓度的变化。结果　辅助期间 ,血浆ET浓度有升高的趋势 ,但与辅助前比较 ,差异无显著性 [(5 1± 11)ng/L与 (4 2± 8)ng/L ,t=0 92 6 ,P >0 0 5 ];肾素浓度在辅助 3h时达到高峰 ,与辅助前比较 ,差异有非常显著意义 [(30 36± 14 11)与 (1783± 4 6 7)ng/L ,t=5 0 13,P <0 0 1) ,以后呈逐渐下降趋势 ,在辅助 9h时为 (194 4± 883)ng/L ,与辅助前相比 ,差异无显著性 (t=0 6 4 4 ,P >0 0 5 ) ;6 k PGF1 α在辅助后 3h时明显增加 ,为 (75± 17)ng/L ,与辅助前[(90± 2 2 )ng/L]相比 ,差异有显著意义 (t=1 4 11,P <0 0 5 ) ,6h达到高峰为 (92± 18)ng/L(t =3 5 33,P <0 0 1) ,9h时下降为 (90± 2 2 )ng/L(t =2 5 16 ,P <0 0 5 )。结论　在 9h左心辅助期间 ,血浆中ET并无明显减少 ;血管内皮释放肾素有短暂增加 ;前列腺素呈持续性增加     

Quantitative and qualitative studies of antibody-induced mesangial cell damage in the rat

Intravenous administration of heterologous anti-rat thymocyte serum (ATS), which reacts with a Thy-1-like antigen present on rat glomerular mesangial cells, caused lytic (1 hr to 2 days), hypercellular (4 to 14 days), and sclerotic (2 to 3 months) mesangial lesions in Lewis rats. The normal control of 48.6 +/- 7.9 (mean +/- SD) glomerular nuclei on histologic section decreased significantly (P less than 0.001) to 39.8 +/- 6.1, 37.4 +/- 6.0, and 38.9 +/- 6.8 at one hour, four hours and two days after ATS administration, respectively. Thereafter glomerular nuclei increased to 54.7 +/- 11.5 (P less than 0.05) at four days, 62.5 +/- 9.6 (P less than 0.001) at one week and 64.1 +/- 14.2 (P less than 0.001) at two weeks, and normalized (P greater than 0.05) to 49.4 +/- 8.9 at one month and 50.6 +/- 9.0 at three months. By electron microscopy, glomerular damage in the lytic stage was restricted to mesangial cells and was manifested as hydropic degeneration or lysis. Rabbit IgG and rat C3 were found in the mesangium one hour after injection; they decreased at two days and were negligible at four days. By paired label isotope study, 11.6 micrograms of antibody bound per 7.6 X 10(4) glomeruli at one hour was needed to induce mesangial cell degeneration. No or only minimal changes in proteinuria and in serum creatinine were observed with the dosage used in this rat strain.(ABSTRACT TRUNCATED AT 250 WORDS)     

Irradiation with 780 nm diode laser attenuates inflammatory cytokines but upregulates nitric oxide in lipopolysaccharide-stimulated macrophages: implications for the prevention of aneurysm progression

BACKGROUND AND OBJECTIVES: Low level laser irradiation (LLLI) has been shown to reduce inflammation in a variety of clinical situations. We have shown that LLLI (780 nm) increases aortic smooth muscle cell proliferation and matrix protein secretion and modulates activity and expression of matrix metalloproteinases. Inflammation is a major component of arteriosclerotic diseases including aneurysm. Macrophage recruitment and secretion of pro-inflammatory cytokines and the vasodilator, nitric oxide (NO), are central to most immune responses in the arterial wall. The present study was designed to determine the effect of LLLI on cytokine gene expression and secretion as well as gene expression of inducible nitric oxide synthase (iNOS) and NO production in lipopolysaccharide (LPS)-stimulated macrophages. STUDY DESIGN/MATERIALS AND METHODS: Murine monocyte/macrophages (RAW 264.7) were irradiated with a 780 nm diode laser (2 mW/cm(2), 2.2 J/cm(2)) during stimulation with LPS (0, 0.1, and 1 microg/ml). Gene expression of chemokines, cytokines, and iNOS were assessed by RT-PCR. Secretion of interleukin (IL)-1beta and monocyte chemotactic protein (MCP)-1 and NO were assessed by ELISA and the Griess reaction, respectively. RESULTS: LLLI reduced gene expression of MCP-1, IL-1alpha, IL-10 (P<0.01), IL-1beta, and IL-6 (P<0.05) when cells were stimulated by 1 microg/ml LPS. LLLI reduced LPS-induced secretion of MCP-1 over non-irradiated cells by 17+/-5% and 13+/-5% at 12 hours (0.1 and 1 microg/ml LPS; P<0.01 and P=0.05, respectively), and reduced IL-1beta by 22+/-5% and 25+/-9% at 24 hours (0.1 and 1 microg/ml LPS, P=0.01 and P=0.06, respectively). However, LLLI increased NO secretion after 12 hours (LLLI vs. Control: without LPS, 1.72+/-0.37 vs. 0.95+/-0.4 microM, P<0.05; 0.1 microg/ml LPS, 7.46+/-1.62 vs. 4.44+/-1.73 microM, P=0.06; 1 microg/ml LPS, 10.91+/-3.53 vs. 6.88+/-1.52 microM, P<0.05). CONCLUSIONS: These properties of LLLI, with its effects on smooth muscle cells reported previously, may be of profound therapeutic relevance for arterial diseases such as aneurysm where inflammatory processes and weakening of the matrix structure of the arterial wall are major pathologic components.