Creatine and guanidinoacetate reference values in a French population.

Creatine and guanidinoacetate are biomarkers of creatine metabolism. Their assays in body fluids may be used for detecting patients with primary creatine deficiency disorders (PCDD), a class of inherited diseases. Their laboratory values in blood and urine may vary with age, requiring that reference normal values are given within the age range. Despite the long known role of creatine for muscle physiology, muscle signs are not necessarily the major complaint expressed by PCDD patients. These disorders drastically affect brain function inducing, in patients, intellectual disability, autistic behavior and other neurological signs (delays in speech and language, epilepsy, ataxia, dystonia and choreoathetosis), being a common feature the drop in brain creatine content. For this reason, screening of PCDD patients has been repeatedly carried out in populations with neurological signs. This report is aimed at providing reference laboratory values and related age ranges found for a large scale population of patients with neurological signs (more than 6 thousand patients) previously serving as a background population for screening French patients with PCDD. These reference laboratory values and age ranges compare rather favorably with literature values for healthy populations. Some differences are also observed, and female participants are discriminated from male participants as regards to urine but not blood values including creatine on creatinine ratio and guanidinoacetate on creatinine ratio values. Such gender differences were previously observed in healthy populations; they might be explained by literature differential effects of testosterone and estrogen in adolescents and adults, and by estrogen effects in prepubertal age on SLC6A8 function. Finally, though they were acquired on a population with neurological signs, the present data might reasonably serve as reference laboratory values in any future medical study exploring abnormalities of creatine metabolism and transport.

Screening for primary creatine deficiencies in French patients with unexplained neurological symptoms.

A population of patients with unexplained neurological symptoms from six major French university hospitals was screened over a 28-month period for primary creatine disorder (PCD). Urine guanidinoacetate (GAA) and creatine:creatinine ratios were measured in a cohort of 6,353 subjects to identify PCD patients and compile their clinical, 1H-MRS, biochemical and molecular data. Six GAMT [N-guanidinoacetatemethyltransferase (EC 2.1.1.2)] and 10 X-linked creatine transporter (SLC6A8) but no AGAT (GATM) [L-arginine/glycine amidinotransferase (EC 2.1.4.1)] deficient patients were identified in this manner. Three additional affected sibs were further identified after familial inquiry (1 brother with GAMT deficiency and 2 brothers with SLC6A8 deficiency in two different families). The prevalence of PCD in this population was 0.25% (0.09% and 0.16% for GAMT and SLC6A8 deficiencies, respectively). Seven new PCD-causing mutations were discovered (2 nonsense [c.577C > T and c.289C > T] and 1 splicing [c.391 + 15G > T] mutations for the GAMT gene and, 2 missense [c.1208C > A and c.926C > A], 1 frameshift [c.930delG] and 1 splicing [c.1393-1G > A] mutations for the SLC6A8 gene). No hot spot mutations were observed in these genes, as all the mutations were distributed throughout the entire gene sequences and were essentially patient/family specific. Approximately one fifth of the mutations of SLC6A8, but not GAMT, were attributed to neo-mutation, germinal or somatic mosaicism events. The only SLC6A8-deficient female patient in our series presented with the severe phenotype usually characterizing affected male patients, an observation in agreement with recent evidence that is in support of the fact that this X-linked disorder might be more frequent than expected in the female population with intellectual disability.

Effects of hydrogen sulfide on hemodynamics, inflammatory response and oxidative stress during resuscitated hemorrhagic shock in rats.

INTRODUCTION: Hydrogen sulfide (H2S) has been shown to improve survival in rodent models of lethal hemorrhage. Conversely, other authors have reported that inhibition of endogenous H2S production improves hemodynamics and reduces organ injury after hemorrhagic shock. Since all of these data originate from unresuscitated models and/or the use of a pre-treatment design, we therefore tested the hypothesis that the H2S donor, sodium hydrosulfide (NaHS), may improve hemodynamics in resuscitated hemorrhagic shock and attenuate oxidative and nitrosative stresses. METHODS: Thirty-two rats were mechanically ventilated and instrumented to measure mean arterial pressure (MAP) and carotid blood flow (CBF). Animals were bled during 60 minutes in order to maintain MAP at 40 ± 2 mm Hg. Ten minutes prior to retransfusion of shed blood, rats randomly received either an intravenous bolus of NaHS (0.2 mg/kg) or vehicle (0.9% NaCl). At the end of the experiment (T = 300 minutes), blood, aorta and heart were harvested for Western blot (inductible Nitric Oxyde Synthase (iNOS), Nuclear factor-κB (NF-κB), phosphorylated Inhibitor κB (P-IκB), Inter-Cellular Adhesion Molecule (I-CAM), Heme oxygenase 1(HO-1), Heme oxygenase 2(HO-2), as well as nuclear respiratory factor 2 (Nrf2)). Nitric oxide (NO) and superoxide anion (O2(-)) were also measured by electron paramagnetic resonance. RESULTS: At the end of the experiment, control rats exhibited a decrease in MAP which was attenuated by NaHS (65 ± 32 versus 101 ± 17 mmHg, P < 0.05). CBF was better maintained in NaHS-treated rats (1.9 ± 1.6 versus 4.4 ± 1.9 ml/minute P < 0.05). NaHS significantly limited shock-induced metabolic acidosis. NaHS also prevented iNOS expression and NO production in the heart and aorta while significantly reducing NF-kB, P-IκB and I-CAM in the aorta. Compared to the control group, NaHS significantly increased Nrf2, HO-1 and HO-2 and limited O2(-) release in both aorta and heart (P < 0.05). CONCLUSIONS: NaHS is protective against the effects of ischemia reperfusion induced by controlled hemorrhage in rats. NaHS also improves hemodynamics in the early resuscitation phase after hemorrhagic shock, most likely as a result of attenuated oxidative stress. The use of NaHS hence appears promising in limiting the consequences of ischemia reperfusion (IR).

Mitochondrial bioenergetic background confers a survival advantage to HepG2 cells in response to chemotherapy.

Cancer cells mainly rely on glycolysis for energetic needs, and mitochondrial ATP production is almost inactive. However, cancer cells require the integrity of mitochondrial functions for their survival, such as the maintenance of the internal membrane potential gradient (DeltaPsim). It thus may be predicted that DeltaPsim regeneration should depend on cellular capability to produce sufficient ATP by upregulating glycolysis or recruiting oxidative phosphorylation (OXPHOS). To investigate this hypothesis, we compared the response to an anticancer agent chloroethylnitrosourea (CENU) of two transformed cell lines: HepG2 (hepatocarcinoma) with a partially differentiated phenotype and 143B (osteosarcoma) with an undifferentiated one. These cells types differ by their mitochondrial OXPHOS background; the most severely impaired being that of 143B cells. Treatment effects were tested on cell proliferation, O(2) consumption/ATP production coupling, DeltaPsim maintenance, and global metabolite profiling by NMR spectroscopy. Our results showed an OXPHOS uncoupling and a lowered DeltaPsim, leading to an increased energy request to regenerate DeltaPsim in both models. However, energy request could not be met by undifferentiated cells 143B, which ATP content decreased after 48 h leading to cell death, while partially differentiated cells (HepG2) could activate their oxidative metabolism and escape chemotherapy. We propose that mitochondrial OXPHOS background confers a survival advantage to more differentiated cells in response to chemotherapy. This suggests that the mitochondrial bioenergetic background of tumors should be considered for anticancer treatment personalization.

Gastric bypass is not associated with protein malnutrition in morbidly obese patients.

BACKGROUND: Patients undergoing bariatric surgery with a gastric bypass lose about 66% of excess weight. Although this procedure induces weight loss, it is unknown whether it leads to protein malnutrition, which is studied here. METHODS: One hundred ten obese patients (body mass index, 47.9 +/- 8.6 kg/m(2)) undergoing gastric bypass had a measurement of plasma albumin and transthyretin (formerly prealbumin) and a calculation of nutritional risk index (NRI) before and throughout the 2 years following the surgery. RESULTS: All but five patients lost more than 15% of initial weight; the mean loss of excess weight was 65.2 +/- 26.4% at 2 years. Plasma concentrations of albumin and transthyretin decreased after surgery, but while albumin returned to initial values after 12 months, transthyretin remained low. Only one patient had an albumin below 30 g/l; another one had a transthyretin lower than 110 mg/l. All NRI scores were lower than 83.5 (62 +/- 5, ranging 44-70), qualifying patients for severe malnutrition. CONCLUSION: Malnutrition is difficult to diagnose in obese patients undergoing surgery. The large weight loss is most often not associated with protein malnutrition. Whether gastric bypass induces protein malnutrition remains to be established.

High birth weight and early postnatal weight gain protect obese children and adolescents from truncal adiposity and insulin resistance: metabolically healthy but obese subjects?

OBJECTIVE: Low birth weight (LBW), no early catch-up weight, and subsequent fat accumulation have been associated with increased risks of insulin resistance from childhood onward and later cardiovascular disease. We sought to clarify the effects of high birth weight (HBW) and postnatal weight gain on insulin resistance. RESEARCH DESIGN AND METHODS: A total of 117 obese children aged 10.4 +/- 2.4 years were divided into three groups according to fetal growth after exclusion of maternal diabetes. They were comparable for age, sex, puberty, and percent body fat. Customized French birth weight standards, adjusted for maternal characteristics and gestation number, identified subjects with true altered fetal growth: 32 had increased fetal growth according to customized standards (HBWcust), 52 were eutrophic, and 33 had restricted fetal growth according to customized standards (LBWcust). Fat distribution by dual-energy X-ray absorptiometry, insulin sensitivity indexes from an oral glucose tolerance test (OGTT), and leptin, adiponectin, and visfatin levels were compared between groups. RESULTS: The HBWcust subjects had a higher adiponectin level, higher whole-body insulin sensitivity index (WBISI), and lower hepatic insulin resistance index, lower insulin and free fatty acid concentrations during OGTT, and lower trunk fat percent than eutrophic (P < 0.05) and LBWcust subjects (P < 0.05). Besides birth weight, weight gain between 0 and 2 years was a positive predictor (P < 0.05) of WBISI, whereas weight gain after 4 years was a negative predictor (P < 0.05). CONCLUSIONS: HBW and early weight gain may program insulin sensitivity and adipose tissue metabolism and contribute to so-called metabolically healthy obesity.

Hemodynamic and antifibrotic effects of a selective liver nitric oxide donor V-PYRRO/NO in bile duct ligated rats.

AIM: To assess whether a liver specific nitric oxide (NO) donor (V-PYRRO/NO) would prevent the development of portal hypertension and liver fibrosis in rats with bile duct ligation (BDL). METHODS: Treatment (placebo or V-PYRRO/NO 0.53 micromol/kg per hour) was administered i.v. to rats 2 d before BDL (D-2) and maintained until the day of hemodynamic measurement (D26). Intra-hepatic NO level was estimated by measuring liver cGMP level. Effects of V-PYRRO/NO on liver fibrosis and lipid peroxidation were also assessed. RESULTS: Compared to placebo treatment, V-PYRRO/NO improved splanchnic hemodynamics in BDL rats: portal pressure was significantly reduced by 27% (P<0.0001) and collateral circulation development was almost completely blocked (splenorenal shunt blood flow by 74%, P=0.007). Moreover, V-PYRRO/NO significantly prevented liver fibrosis development in BDL rats (by 30% in hepatic hydroxyproline content and 31% in the area of fibrosis, P<0.0001 respectively), this effect being probably due to a decrease in lipid peroxidation by 44% in the hepatic malondialdehyde level (P=0.007). Interestingly, we observed a significant and expected increase in liver cGMP, without any systemic hemodynamic effects (mean arterial pressure, vascular systemic resistance and cardiac output) in both sham-operated and BDL rats treated with V-PYRRO/NO. This result is in accordance with studies on V-PYRRO/NO metabolism showing a specific release of NO in the liver. CONCLUSION: Continuous administrations of V-PYRRO/NO in BDL rats improved liver fibrosis and splanchnic hemodynamics without any noxious systemic hemo-dynamic effects.

Influence of intensity of food restriction on skeletal muscle mitochondrial energy metabolism in rats.

Variable durations of food restriction (FR; lasting weeks to years) and variable FR intensities are applied to animals in life span-prolonging studies. A reduction in mitochondrial proton leak is suggested as a putative mechanism linking such diet interventions and aging retardation. Early mechanisms of mitochondrial metabolic adaptation induced by FR remain unclear. We investigated the influence of different degrees of FR over 3 days on mitochondrial proton leak and mitochondrial energy metabolism in rat hindlimb skeletal muscle. Animals underwent 25, 50, and 75% and total FR compared with control rats. Proton leak kinetics and mitochondrial functions were investigated in two mitochondrial subpopulations, intermyofibrillar (IMF) and subsarcolemmal (SSM) mitochondria. Regardless of the degree of restriction, skeletal muscle mass was not affected by 3 days of FR. Mitochondrial basal proton conductance was significantly decreased in 50% restricted rats in both mitochondrial subpopulations (46 and 40% for IMF and SSM, respectively) but was unaffected in other groups compared with controls. State 3 and uncoupled state 3 respiration rates were decreased in SSM mitochondria only for 50% restricted rats when pyruvate + malate was used as substrate (-34.5 and -38.9% compared with controls, P < 0.05). IMF mitochondria respiratory rates remained unchanged. Three days of FR, particularly at 50% FR, were sufficient to lower mitochondria energetic metabolism in both mitochondrial populations. Our study highlights an early step in mitochondrial adaptation to FR and the influence of the severity of restriction on this adaptation. This step may be involved in an aging-retardation process.

Maternal and cord blood ghrelin in the pregnancies of smoking mothers: possible markers of nutrient availability for the fetus.

AIMS: To investigate the role of ghrelin in maternal and fetal metabolism, we determined its value in maternal smoking, a specific cause of reduced placenta function and fetal growth. METHODS: In 85 normal term pregnancies, 42 in smoking and 43 in non-smoking mothers, we measured ghrelin in the maternal blood at the onset of labor and in the cord blood of their 85 singletons immediately after birth. We determined the relationships between ghrelin and placental GH (PGH), pituitary GH (pitGH), and IGF-I. RESULTS: The newborns of smoking mothers weighed 0.24 kg less (p < 0.05) than those of non-smoking mothers. Cord blood ghrelin was 71% higher and PGH and cord blood IGF-I were 34% and 32% lower, respectively, in the pregnancies of smoking compared with non-smoking mothers (p < 0.05). Cord blood ghrelin was unrelated to pitGH and cord blood IGF-I. Maternal ghrelin was unchanged in smoking mothers, increased with maternal fasting duration (r = 0.26, p < 0.05), showed no correlation with PGH and negative correlation with cord blood IGF-I (r = -0.42, p < 0.01). CONCLUSION: The decrease in placental function and fetal growth in smoking mothers is associated with an increase in cord blood ghrelin, and no change in maternal ghrelin. Maternal ghrelin concentration increases with fasting, and is negatively correlated with cord blood IGF-I: it may signal a reduction in the level of nutrients available for placental transfer. No correlation supports a role for ghrelin in PGH or pitGH secretion.

Dinitrophenol-induced mitochondrial uncoupling in vivo triggers respiratory adaptation in HepG2 cells.

Here, we show that 3 days of mitochondrial uncoupling, induced by low concentrations of dinitrophenol (10 and 50 microM) in cultured human HepG2 cells, triggers cellular metabolic adaptation towards oxidative metabolism. Chronic respiratory uncoupling of HepG2 cells induced an increase in cellular oxygen consumption, oxidative capacity and cytochrome c oxidase activity. This was associated with an upregulation of COXIV and ANT3 gene expression, two nuclear genes that encode mitochondrial proteins involved in oxidative phosphorylation. Glucose consumption, lactate and pyruvate production and growth rate were unaffected, indicating that metabolic adaptation of HepG2 cells undergoing chronic respiratory uncoupling allows continuous and efficient mitochondrial ATP production without the need to increase glycolytic activity. In contrast, 3 days of dinitrophenol treatment did not change the oxidative capacity of human 143B.TK(-) cells, but it increased glucose consumption, lactate and pyruvate production. Despite a large increase in glycolytic metabolism, the growth rate of 143B.TK(-) cells was significantly reduced by dinitrophenol-induced mitochondrial uncoupling. We propose that chronic respiratory uncoupling may constitute an internal bioenergetic signal, which would initiate a coordinated increase in nuclear respiratory gene expression, which ultimately drives mitochondrial metabolic adaptation within cells.

ANT2 isoform required for cancer cell glycolysis.

The three adenine nucleotide translocator (ANT1 to ANT3) isoforms, differentially expressed in human cells, play a crucial role in cell bioenergetics by catalyzing ADP and ATP exchange across the mitochondrial inner membrane. In contrast to differentiated tissue cells, transformed cells, and their rho(0) derivatives, i.e. cells deprived of mitochondrial DNA, sustain a high rate of glycolysis. We compared the expression pattern of ANT isoforms in several transformed human cell lines at different stages of the cell cycle. The level of ANT2 expression and glycolytic ATP production in these cell lines were in keeping with their metabolic background and their state of differentiation. The sensitivity of the mitochondrial inner membrane potential (Deltapsi) to several inhibitors of glycolysis and oxidative phosphorylation confirmed this relationship. We propose a new model for ATP uptake in cancer cells implicating the ANT2 isoform, in conjunction with hexokinase II and the beta subunit of mitochondrial ATP synthase, in the Deltapsi maintenance and in the aggressiveness of cancer cells.

Maternal smoking is associated with mitochondrial DNA depletion and respiratory chain complex III deficiency in placenta.

Maternal smoking during pregnancy is often associated with a decrease in placental function, which might lead to intrauterine growth retardation. Because tobacco is known to alter the mitochondrial respiratory function in cardiomyocytes and lung tissue, we hypothesized that placental mitochondrial function could be altered by maternal smoking. Placental mitochondria from 9 smoking and 19 nonsmoking mothers were isolated by differential centrifugation. Mitochondrial oxygen consumption was measured by polarography, and the enzymatic activity of each complex of the electron transport chain was assessed by spectrophotometry. In addition, the relative content in mitochondrial DNA (mtDNA) was determined by real-time quantitative PCR in placentas from seven smoking and seven nonsmoking mothers. We observed a 29% reduction in the enzymatic activity of complex III in the placental mitochondria from smokers compared with nonsmokers (P = 0.03). The relative content of mtDNA (with respect to the beta-globin gene) was reduced by 37% in the placental tissue from smokers compared with nonsmokers (P < 0.02). Both the enzymatic activity of complex III and mtDNA content were inversely related with the daily consumption of cigarettes, and mtDNA content was correlated with cord blood insulin-like growth factor-binding protein-3 (r = 0.74, P < 0.01), a marker of fetal growth. These results show that maternal smoking is associated with placental mitochondrial dysfunction, which might contribute to restricted fetal growth by limiting energy availability in cells.

Divergent effect of endogenous and exogenous sex steroids on the insulin-like growth factor I response to growth hormone in short normal adolescents.

The lower responsiveness to GH in women than in men is probably due to a divergent effect of gonadal steroids. It is unknown, however, how the progressive increase in sex steroid production that occurs during puberty affects this responsiveness. To compare the effects of puberty and sex steroid administration on responsiveness to GH, we used the IGF-I generation test, in which the peak IGF-I level 24 h after a single injection of GH (2 mg/m2) was studied in 117 healthy short subjects (56 females and 61 males). The subjects, aged 8-16 yr, were divided into four groups: prepuberty, early puberty, midpuberty, or pubertal delay. In the latter group, the IGF-I response was determined before and after priming with oral 17beta-estradiol in girls and im testosterone in boys. We also tested for an association between body composition (by dual energy x-ray absorptiometry) and the IGF-I response to GH. The IGF-I increment in response to GH (change in IGF-I from baseline) was correlated with the growth velocity sd score (P < 0.05). Progression throughout puberty was associated with an increase in both baseline IGF-I (P < 0.05) and the IGF-I increment in response to GH (P < 0.05), with no gender difference. Pubertal category (pre-, early, and midpuberty; P < 0.05) and fat percentage (P < 0.05) were the main positive predictors of the IGF-I increment in response to GH, expressed as micrograms per liter as well as sd score, independently of baseline IGF-I. After sex steroid priming, both the GH peak in response to insulin-induced hypoglycemia and baseline IGF-I were increased (P < 0.05, after vs. before sex steroid). However, the IGF-I increment in response to GH decreased after oral 17beta-estradiol (P < 0.05), whereas it was unchanged after testosterone administration. Endogenous gonadal steroid secretion appears to result in increased responsiveness to GH in peripubertal girls and boys. By contrast, exogenous estrogen and testosterone, respectively, produce a relative decrease and no change in responsiveness to GH in similar populations, possibly through the achievement of sex steroid concentrations exceeding physiological ranges for age. Fat percentage was a positive determinant of the responsiveness to GH, suggesting a link between the energy stores and the anabolic action of GH.

Food restriction affects energy metabolism in rat liver mitochondria.

To examine the effect of 50% food restriction over a period of 3 days on mitochondrial energy metabolism, liver mitochondria were isolated from ad libitum and food-restricted rats. Mitochondrial enzyme activities and oxygen consumption were assessed spectrophotometrically and polarographically. With regard to body weight loss (-5%), food restriction decreased the liver to body mass ratio by 7%. Moreover, in food-restricted rats, liver mitochondria displayed diminished state 3 (-30%), state 4-oligomycin (-26%) and uncoupled state (-24%) respiration rates in the presence of succinate. Furthermore, "top-down" elasticity showed that these decreases were due to an inactivation of reactions involved in substrate oxidation. Therefore, it appears that rats not only adapt to food restriction through simple passive mechanisms, such as liver mass loss, but also through decreased mitochondrial energetic metabolism.

Mitochondrial energy metabolism in a model of undernutrition induced by dexamethasone.

The present investigation was undertaken to evaluate whether mitochondrial energy metabolism is altered in a model of malnutrition induced by dexamethasone (DEX) treatment (1.5 mg/kg per d for 5 d). The gastrocnemius and liver mitochondria were isolated from DEX-treated, pair-fed (PF) and control (CON) rats. Body weight was reduced significantly more in the DEX-treated group (-16%) than in the PF group (-9%). DEX treatment increased liver mass (+59% v. PF, +23% v. CON) and decreased gastrocnemius mass. Moreover, in DEX-treated rats, liver mitochondria had an increased rate of non-phosphorylative O2 consumption with all substrates (approximately +42%). There was no difference in enzymatic complex activities in liver mitochondria between rat groups. Collectively, these results suggest an increased proton leak and/or redox slipping in the liver mitochondria of DEX-treated rats. In addition, DEX decreased the thermodynamic coupling and efficiency of oxidative phosphorylation. We therefore suggest that this increase in the proton leak and/or redox slip in the liver is responsible for the decrease in the thermodynamic efficiency of energy conversion. In contrast, none of the variables of energy metabolism determined in gastrocnemius mitochondria was altered by DEX treatment. Therefore, it appears that DEX specifically affects mitochondrial energy metabolism in the liver.

Dexamethasone treatment specifically increases the basal proton conductance of rat liver mitochondria.

We investigated the role that mitochondrial proton leak may play in the glucocorticoid-induced hypermetabolic state. Sprague-Dawley rats were injected with dexamethasone over a period of 5 days. Liver mitochondria and gastrocnemius subsarcolemmal and intermyofibrillar mitochondria were isolated from dexamethasone-treated, pair-fed and control rats. Respiration and membrane potential were measured simultaneously using electrodes sensitive to oxygen and to the potential-dependent probe triphenylmethylphosphonium, respectively. Five days of dexamethasone injection resulted in a marked increase in the basal proton conductance of liver mitochondria, but not in the muscle mitochondrial populations. This effect would have a modest impact on energy expenditure in rats.

Low-dose terlipressin improves systemic and splanchnic hemodynamics in fluid-challenged endotoxic rats.

OBJECTIVE: Vasopressin has been used to treat arterial hypotension associated with hyperdynamic vasoplegic states, but detrimental effects on splanchnic circulation have been reported. We tested the effects of a low-dose vasopressin analogue, terlipressin (6 microg/kg), on systemic and splanchnic hemodynamics in fluid-challenged endotoxic rats (lipopolysaccharide, 30 mg/kg in 1 hr). DESIGN: Prospective, randomized, controlled experimental study with repeated measures. SETTING: Investigational animal laboratory. SUBJECTS: A total of 77 rats were divided into five groups: group C, control (17 rats); group E, LPS (18 rats); group EF, LPS plus fluid challenge (18 rats); group EFT, LPS plus fluid challenge plus terlipressin (18 rats); and group ET, LPS plus terlipressin (seven rats). INTERVENTIONS: Rats were anesthetized, mechanically ventilated, and instrumented to measure heart rate, mean arterial pressure, and abdominal aortic and mesenteric vein indexed blood flows; ileal microcirculation was assessed by laser Doppler. After LPS infusion, rats experienced an endotoxic shock and were resuscitated after the allocation group. The fluid challenge was targeted to maintain mean arterial pressure of >90 mm Hg and aortic blood flow at baseline values. MEASUREMENTS AND MAIN RESULTS: Terlipressin significantly (p <.05) increased mean arterial pressure without decreasing indexed aortic blood flow and heart rate in the fluid-challenged endotoxic rats (EFT) compared with EF rats and had detrimental effects in hypodynamic endotoxic rats (ET). Fluid challenge significantly (p <.05) increased mesenteric vein blood flow in both the EF and EFT groups, and terlipressin had no detrimental effect on mesenteric blood flow. Terlipressin significantly (p <.05) increased ileal microcirculation in fluid-challenged endotoxic rats (EF and EFT) but not in hypodynamic endotoxic rats (E and ET). CONCLUSION: Low-dose terlipressin in fluid-challenged endotoxic rats improved systemic and splanchnic hemodynamics and improved the ileal microcirculation.

Hemodynamic and antifibrotic effects of losartan in rats with liver fibrosis and/or portal hypertension.

BACKGROUND/AIMS: To assess the effects of the early and chronic administration of losartan--a specific angiotensin II receptor antagonist--in the prevention of hepatic fibrosis and portal hypertension. METHODS/RESULTS: (1) In CCl(4) rats, losartan at 5 and 10 mg/kg per day significantly decreased portal pressure (-11, -18%, respectively), splenorenal shunt blood flow (-60, -80%) and liver fibrosis (liver hydroxyproline and area of fibrosis) without significant changes in mortality and mean arterial pressure (MAP). (2) In bile duct ligated (BDL) rats, losartan at 5 mg/kg per day significantly decreased portal pressure (-14%), splenorenal shunt blood flow (-70%) and liver fibrosis. Losartan at 10 mg/kg per day significantly worsened liver and renal functions, mortality and liver fibrosis, without significant changes in portal pressure and splenorenal shunt blood flow. Losartan at 5 and 10 mg/kg per day significantly decreased MAP (-24, -30%). (3) In portal vein ligated (PVL) rats, losartan significantly decreased MAP (-12%) but did not change portal pressure or splenorenal shunt blood flow. CONCLUSIONS: In BDL and CCl(4) rats, losartan has beneficial effects on splanchnic hemodynamics and liver fibrosis. Losartan might decrease hepatic resistances in fibrotic liver. Losartan decreased MAP except in CCl(4) rats. Higher dosage of losartan had deleterious effects in BDL rats.

Oxygen consumption and expression of the adenine nucleotide translocator in cells lacking mitochondrial DNA.

It has been shown previously that human rho degrees cells, deprived of mitochondrial DNA and consequently of functional oxidative phosphorylation, maintain a mitochondrial membrane potential, which is necessary for their growth. The goal of our study was to determine the precise origin of this membrane potential in three rho degrees cell lines originating from the human HepG2, 143B, and HeLa S3 cell lines. Residual cyanide-sensitive oxygen consumption suggests the persistence of residual mitochondrial respiratory chain activity, about 8% of that of the corresponding parental cells. The fluorescence emitted by the three rho degrees cell lines in the presence of a mitochondrial specific fluorochrome was partially reduced by a protonophore, suggesting the existence of a proton gradient. The mitochondrial membrane potential is maintained both by a residual proton gradient (up to 45 to 50% of the potential) and by other ion movements such as the glycolytic ATP(4-) to mitochondrial ADP(3-) exchange. The ANT2 gene, encoding isoform 2 of the adenine nucleotide translocator, is overexpressed in rho degrees HepG2 and 143B cells strongly dependent on glycolytic ATP synthesis, as compared to the corresponding parental cells, which present a more oxidative metabolism. In rho degrees HeLa S3 cells, originating from the HeLa S3 cell line, which already displays a glycolytic energy status, ANT2 gene expression was not higher as in parental cells. Mitochondrial oxygen consumption and ANT2 gene overexpression vary in opposite ways and this suggests that these two parameters have complementary roles in the maintenance of the mitochondrial membrane potential in rho degrees cells.