Transcriptome profiling reveals exposure to predicted end-of-century ocean acidification as a stealth stressor for Atlantic cod larvae.

Ocean acidification (OA), a direct consequence of increasing atmospheric CO2 concentration dissolving in ocean waters, is impacting many fish species. Little is known about the molecular mechanisms underlying the observed physiological impacts in fish. We used RNAseq to characterize the transcriptome of 3 different larval stages of Atlantic cod (Gadus morhua) exposed to simulated OA at levels (1179 µatm CO2) representing end-of-century predictions compared to controls (503 µatm CO2), which were shown to induce tissue damage and elevated mortality in G. morhua. Only few genes were differentially expressed in 6 and 13 days-post-hatching (dph) (3 and 16 genes, respectively), during a period when maximal mortality as a response to elevated pCO2 occurred. At 36 dph, 1413 genes were differentially expressed, most likely caused by developmental asynchrony between the treatment groups, with individuals under OA growing faster. A target gene analysis revealed only few genes of the universal and well-defined cellular stress response to be differentially expressed. We thus suggest that predicted ocean acidification levels constitute a "stealth stress" for early Atlantic cod larvae, with a rapid breakdown of cellular homeostasis leading to organismal death that was missed even with an 8-fold replication implemented in this study.

Effects of parental acclimation and energy limitation in response to high CO2 exposure in Atlantic cod.

Ocean acidification (OA), the dissolution of excess anthropogenic carbon dioxide in ocean waters, is a potential stressor to many marine fish species. Whether species have the potential to acclimate and adapt to changes in the seawater carbonate chemistry is still largely unanswered. Simulation experiments across several generations are challenging for large commercially exploited species because of their long generation times. For Atlantic cod (Gadus morhua), we present first data on the effects of parental acclimation to elevated aquatic CO2 on larval survival, a fundamental parameter determining population recruitment. The parental generation in this study was exposed to either ambient or elevated aquatic CO2 levels simulating end-of-century OA levels (~1100 µatm CO2) for six weeks prior to spawning. Upon fully reciprocal exposure of the F1 generation, we quantified larval survival, combined with two larval feeding regimes in order to investigate the potential effect of energy limitation. We found a significant reduction in larval survival at elevated CO2 that was partly compensated by parental acclimation to the same CO2 exposure. Such compensation was only observed in the treatment with high food availability. This complex 3-way interaction indicates that surplus metabolic resources need to be available to allow a transgenerational alleviation response to ocean acidification.

Fishes in a changing world: learning from the past to promote sustainability of fish populations.

Populations of fishes provide valuable services for billions of people, but face diverse and interacting threats that jeopardize their sustainability. Human population growth and intensifying resource use for food, water, energy and goods are compromising fish populations through a variety of mechanisms, including overfishing, habitat degradation and declines in water quality. The important challenges raised by these issues have been recognized and have led to considerable advances over past decades in managing and mitigating threats to fishes worldwide. In this review, we identify the major threats faced by fish populations alongside recent advances that are helping to address these issues. There are very significant efforts worldwide directed towards ensuring a sustainable future for the world's fishes and fisheries and those who rely on them. Although considerable challenges remain, by drawing attention to successful mitigation of threats to fish and fisheries we hope to provide the encouragement and direction that will allow these challenges to be overcome in the future.

Feeding ecology of indigenous and non-indigenous fish species within the family Sphyraenidae.

The feeding ecology of two common indigenous (Sphyraena viridensis and Sphyraena sphyraena) and one abundant non-indigenous sphyraenid species, Sphyraena chrysotaenia, of Indo-Pacific Ocean origin, was investigated in an area of the eastern Mediterranean Sea. The stomach contents of 738 individuals of varying size, collected during the period December 2008 to August 2009, were examined. The dietary analyses revealed that all three species were specialized piscivores with a diet consisting of >90% fish, both by number and mass. Concurrent sampling of the fish assemblage made it possible to calculate selectivity as well as diet breadth and overlap of these strict piscivores. Even though several prey species were found in the stomachs of the three predators examined, selectivity towards Atherina boyeri was highly significant. For all species examined, >70% of the diet by mass was made up by three indigenous species of commercial value: Spicara smaris, Boops boops and A. boyeri. Diet breadth and size of prey increased with increasing body size for all predators. With increased body size, the diet overlap between indigenous and non-indigenous species decreased. This could be attributed to increased diet breadth and the specific life-history characteristics of indigenous species developing into larger individuals. During winter, the condition factor of the non-indigenous species was significantly lower than that of the indigenous, indicating that winter conditions in the Mediterranean Sea may limit its further expansion north and westward. With this study, the gap in knowledge of the feeding preferences of the most abundant piscivorous species found in coastal areas of the study region is filled. Additionally, the results indicate that non-indigenous species familial affiliation to indigenous ones does not facilitate invasion success.

Alpha-lipoic acid improves vascular endothelial function in patients with type 2 diabetes: a placebo-controlled randomized trial.

OBJECTIVE: The aim of this study was to investigate the effect of alpha-lipoic acid (ALA) treatment on endothelium-dependent and -independent vasodilatation, assessed by forearm blood flow (FBF), in patients with type 2 diabetes mellitus. RESEARCH DESIGN AND METHODS: A total of 30 subjects with type 2 diabetes were included in this randomized, controlled, double-blinded, parallel group study. FBF responses to intra-arterial acetylcholine (ACh) and glycerol trinitrate (GTN) were measured before and after 21 days of intravenous treatment with 600 mg alpha-lipoic acid or placebo. RESULTS: FBF responses were comparable at baseline. After treatment, FBF reactivity to ACh and GTN was unchanged in subjects receiving placebo. By contrast, ALA treatment increased endothelium-dependent vasodilatation to ACh (P < 0.05) but not to GTN compared with baseline. CONCLUSIONS: Intravenous ALA treatment improves endothelium-dependent vasodilatation in patients with type 2 diabetes, in the absence of effects on forearm vasomotor function. If this salutary action translates into vascular risk reduction remains to be established.

Postprandial blood glucose level in maintenance hemodialysis patients predicts post-transplant-diabetes-mellitus.

Post-transplant-diabetes-mellitus (PTDM) is a frequent complication after kidney transplantation. One-hundred-and-seven patients with kidney transplantation were screened for the occurrence of PTDM. Of these, full data sets from 49 subjects were available with documented glucose concentrations during maintenance hemodialysis (MHD) and regular clinical follow-up of 7-34 months. For assessment of glucose metabolism the response to a standard meal during MHD was used in normoglycemic patients based on fasting blood glucose. Abnormal postprandial blood glucose concentration was defined as >140 mg/dl 2 h after food intake.Twelve end stage renal disease patients had abnormal postprandial blood glucose on MHD. All 12 subjects but also four MHD patients with normal postprandial and fasting blood glucose values developed PTDM. Multivariate Cox-regression analysis revealed that abnormal postprandial blood glucose is a strong predictor for PTDM (Hazard ratio: 42.3 (IQR: 7.9-227.2); p<0.001). Fasting blood glucose (94 vs. 100 mg/dl) was not different between MHD patients who did (n=16) or did not (n=33) develop PTDM.This study suggests that measurement of postprandial blood glucose during MHD identifies patients who develop PTDM after kidney transplantation. It should be used for screening of patients at risk.

Alcohol acutely increases vascular reactivity together with insulin sensitivity in type 2 diabetic men.

Moderate alcohol consumption is associated with increased insulin sensitivity and reduced cardiovascular risk. We hypothesized that this relates to a direct effect of alcohol and therefore investigated whether acute alcohol intake altered insulin sensitivity or endothelial function in patients with type 2 diabetes. In an open-label two period design, the effect of a single oral dose of 40 g of alcohol (168 ml 40% vodka) on an insulin-modified frequently sampled intravenous glucose tolerance test (FSIGT) and on endothelium-dependent (flow mediated, FMD) or endothelium-independent (glyceroltrinitrate (GTN)-induced) vasodilation of the brachial artery measured by ultrasound was studied. Experiments were carried out in twelve male patients with type 2 diabetes mellitus (64+/-6 years, body mass index 28.4+/-5.7 kg/m (2)). Baseline insulin sensitivity index (S (I)) was 1.10+/-0.34 min (-1).microU (-1).ml, baseline FMD was +4.1+/-3.0%, and GTN-induced vasodilation +7.4+/-2.3% from resting brachial artery diameter. Acute alcohol intake increased alcohol plasma levels to 0.33+/-0.04 per thousand, S (I) to 1.86+/-0.45 min (-1).microU (-1).ml (p<0.05), and FMD to +8.2+/-2.8% (p<0.05), while GTN-induced dilation remained unchanged. No relationship was detectable between the observed changes. We conclude that alcohol intake acutely increases endothelium-dependent brachial artery vasodilation in patients with type 2 diabetes together with insulin sensitivity. This acute effect might explain some beneficial effects of low alcohol consumption in epidemiological observations.

Postprandial intradialytic dysglycaemia and diabetes in maintenance haemodialysis patients.

BACKGROUND: Although the risk of developing dysglycaemia has been investigated in different communities this incidence is poorly studied in patients on maintenance haemodialysis (MHD). MATERIALS AND METHODS: In a multicentre observational cohort study the occurrence of dysglycaemia was assessed in 239 primary normoglycaemic end stage renal disease (ERSD) patients on MHD. Dysglycaemia (fasting blood glucose > 110 mg dL(-1), > 140 mg dL(-1) 2 h after food intake) or diabetes (fasting blood glucose > 126 mg dL(-1) or > 200 mg dL(-1) at any time) were defined according to WHO criteria and cases were compared with age matched controls within the cohort. RESULTS: Dysglycaemia was found in 82 primary normoglycaemic ESRD patients (34%) within 31 months after initiation of MHD. In 31 of these patients type 2 diabetes was diagnosed. When compared with matched control MHD patients differences in body mass index (BMI), HbA1c and postprandial blood glucose were detectable (P < 0.05). Increments in 0.1% of HbA1c were related with 11% higher odds for dysglycaemia (P = 0.002). In a subgroup of 36 primary normoglycaemic MHD patients who developed dysglycaemia event-free survival was 64%, 53%, 31%, 17% and 11% after 1, 2, 3, 4 and 5 years of haemodialysis treatment. CONCLUSION: Onset of dysglycaemia or diabetes is frequent in ESRD patients after onset of chronic haemodialysis. Routine measurement of blood glucose before and after haemodialysis should be implemented as a standard of care during MHD.

Pioglitazone does not affect vascular or inflammatory responses after endotoxemia in humans.

PPARgamma agonists have been proposed to exert more than metabolic benefits, particularly by anti-inflammatory mechanisms. We hypothesized that pioglitazone might modulate inflammatory and vascular responses to lipopolysaccharide (LPS). In a placebo-controlled parallel-group study in 18 healthy male subjects, the E. coli endotoxin model of inflammation (20 IU/kg i. v.) was employed to test the effect of 60 mg pioglitazone over nine days on inflammatory cytokines. Macrovascular function and microvascular blood flow were assessed by brachial artery ultrasound and retinal blood flow parameters, respectively. Pioglitazone increased brachial artery diameter by 5.6% but had no effect on other outcome parameters under resting conditions. LPS increased cytokine levels to peak concentrations of 91.3+/-22.5 ng/ml (IL-6), 261.4+/-60.0 ng/ml (TNFalpha), and 524.5+/-15.3 ng/ml (VCAM-1). The endotoxin caused microvascular vasodilation and increased retinal white blood cell flux, while baseline brachial artery diameter remained unchanged. Pioglitazone had no effect on inflammatory cytokine or adhesion molecule release but mitigated LPS-induced hypotension (p<0.05). Neither brachial artery function nor microvascular blood flow was altered by pioglitazone. In conclusion, acute immune reactions to LPS are not affected by pioglitazone, which exerts subtle vascular effects alone and during endotoxemia. The anti-inflammatory properties of short-term pioglitazone to endotoxins in healthy subjects are therefore limited.

Serum concentrations of retinol-binding protein 4 in women with and without gestational diabetes.

AIMS/HYPOTHESIS: Pregnancy is characterised by temporarily increased insulin resistance. Gestational diabetes occurs when pancreatic beta cell function is unable to compensate for this insulin resistance. Retinol-binding protein 4 (RBP4) could be related to insulin resistance. We hypothesised that RBP4 is elevated in gestational diabetes. METHODS: Serum RBP4, transthyretin and retinol were cross-sectionally measured in 42 women with gestational diabetes and 45 pregnant controls. Of these, 20 women with and 22 without gestational diabetes were included in an additional longitudinal study. RBP4 was determined by enzyme immunometric assay (EIA) and western blot. RESULTS: Women with gestational diabetes had lower RBP4 EIA and western blot levels than controls (median 6.8 [interquartile range, 3.9-14.3] vs 11.3 [7.8-19.9] microg/ml, p < 0.001 and 25.1 [21.7-29.6] vs 26.6 [23.5-32.2] microg/ml, p = 0.026). Transthyretin and the RBP4:transthyretin molar ratio were comparable between the groups. Serum retinol was lower (p < 0.001) and the RBP4 Western blot level: retinol molar ratio was higher in women with gestational diabetes (p = 0.044). RBP4 was not associated with the glucose or homeostasis model assessment of insulin resistance (HOMA-IR), but in gestational diabetes the RBP4:retinol molar ratio correlated with blood glucose and negatively with 2 h post-load insulin. The RBP4:transthyretin ratio correlated with HOMA-IR and fasting insulin in controls. In women with gestational diabetes RBP4 EIA and western blot levels increased after delivery. Retinol increased in both groups, while transthyretin and the RBP4:transthyretin ratio were not altered after parturition. CONCLUSIONS/INTERPRETATION: RBP4 measured by two different techniques is not elevated, but the RBP4:retinol molar ratio is higher and correlates with fasting blood glucose in women with gestational diabetes. Thus, the RBP4:retinol ratio and the RBP4:transthyretin ratio are more informative than RBP4 levels alone when assessing insulin-glucose homeostasis during pregnancy.

Adiponectin concentrations increase during acute FFA elevation in humans treated with rosiglitazone.

The adipocytokine adiponectin is released by adipocytes upon activation of the peroxisome proliferator-activated receptor gamma (PPAR gamma). PPAR gamma has binding sites for thiazolidinediones and free fatty acids (FFAs). To evaluate if adiponectin serum concentrations are synergistically regulated by FFAs and thiazolidinediones IN VIVO plasma FFAs were acutely elevated in healthy subjects pre-treated with rosiglitazone or placebo. Sixteen healthy male subjects (23-37 years) were included in this double-blind, randomized, placebo-controlled parallel-group study. Rosiglitazone 8 mg or placebo was administered daily for 21 days. On the last day plasma FFA concentrations were increased by an intravenous triglyceride/heparin infusion. Blood for determination of adiponectin, C-reactive protein (CRP), leptin, resistin, FFAs, glucose, and insulin was drawn at baseline and on day 21 before and after 5 hours of triglyceride/heparin infusion. Adiponectin concentrations increased and FFA levels decreased in subjects receiving rosiglitazone (all p<0.05 VS. baseline). Lipid infusion significantly increased FFA plasma concentrations, with an attenuated elevation in rosiglitazone-treated subjects. However, adiponectin concentrations were only increased in subjects on rosiglitazone (p=0.018 VS. before lipid infusion), but not in controls. Leptin increased during lipid infusion in subjects receiving placebo but not in those on rosiglitazone. CRP and resistin were not affected by rosiglitazone or FFAs. The acute increase in circulating adiponectin concentrations during acutely elevated FFA depends on PPAR gamma activation in healthy subjects.

Elevated concentrations of asymmetric dimethylarginine are associated with deterioration of glucose tolerance in women with previous gestational diabetes mellitus.

OBJECTIVE: Women with previous gestational diabetes mellitus (GDM) have a high risk for development of type 2 diabetes mellitus. The endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine (ADMA) could be related to disorders of the glucose metabolism. To evaluate if ADMA predicts deterioration of glucose tolerance in women with previous GDM and to assess concentration changes we analysed ADMA in women with previous GDM after delivery and after a median follow-up of 2.75 years (interquartile range: 1.47-4.60). DESIGN: Prospective cohort study. Subjects and methods. ADMA, symmetric dimethylarginine (SDMA) and L-arginine were determined in 77 women with previous GDM who underwent a 75-g oral glucose tolerance test 4 months after delivery and at follow-up. RESULTS: Deterioration in glucose tolerance was observed in 36% of the women with ADMA above and 11% of those with ADMA below the median (0.56 micromol L(-1); P = 0.008, log-rank test). ADMA correlated significantly with mean arterial blood pressure and nonsignificantly with body mass index (P = 0.050) but not with insulin resistance, fasting glucose, lipids or glomerular filtration rate. The fully adjusted hazard ratio for a decline of glucose tolerance during follow-up was 3.94 (95% CI: 1.16-13.37; P = 0.028) for subjects with ADMA above the median. SDMA and L-arginine were not associated with changes in the glucose tolerance status. ADMA and L-arginine decreased significantly during follow-up. CONCLUSIONS: High serum ADMA after delivery is associated with deterioration in glucose tolerance in women with previous GDM and declines in the following years.

Asymmetrical dimethylarginine is related to renal function, chronic inflammation and macroangiopathy in patients with Type 2 diabetes and albuminuria.

AIMS: Patients with Type 2 diabetes mellitus (T2DM) and micro- and macroalbuminuria are at increased cardiovascular risk. The endogenous nitric oxide synthase inhibitor asymmetrical dimethylarginine (ADMA) is increased in renal failure and could promote atherosclerosis. To determine the relationship between ADMA, renal albumin excretion rate (AER) and cardiovascular risk, we studied 103 T2DM patients. METHODS: ADMA, symmetrical dimethylarginine (SDMA) and L-arginine were determined by high-performance liquid chromatography in plasma from 36 normo-, 40 micro- and 27 macroalbuminuric patients with T2DM (age 64 +/- 11 years; 38 women) who had comparable age, sex and metabolic parameters. Forty-six patients had macrovascular disease (MVD). RESULTS: ADMA was significantly increased in patients with micro- and macroalbuminuria [median 0.61 (interquartile range 0.55-0.70) micromol/l and 0.62 (0.50-0.79) micromol/l, respectively] compared with those with normoalbuminuria [0.55 (0.48-0.63) micromol/l; both P < 0.05]. SDMA was elevated in micro- and macroalbuminuria [0.57 (0.42-0.80) micromol/l and 0.64 (0.50-0.96) micromol/l] compared with normoalbuminuric subjects [0.44 (0.37-0.53) micromol/l; both P < 0.01]. Patients with increased AER and MVD had higher ADMA and SDMA compared with those without MVD (both P < 0.001). L-arginine was comparable between all groups. ADMA correlated significantly with high-sensitivity C-reactive protein (hsCRP) and glomerular filtration rate (GFR) but not with the extent of albumin excretion, body mass index, fasting glucose, HbA(1c) or plasma lipids. CONCLUSIONS: Increased ADMA in T2DM patients with albuminuria is linked to cardiovascular disease and is associated with renal dysfunction and subclinical inflammation.

Effect of rosiglitazone on visfatin and retinol-binding protein-4 plasma concentrations in HIV-positive patients.

Thiazolidinediones (TZD) may improve insulin resistance in patients with diabetes and HIV. The novel adipocytokines visfatin and retinol-binding protein-4 (RBP-4) have been proposed to influence the development of impaired glucose tolerance. The impact of TZD on these cytokines is yet unknown. In this randomized, double-blind, placebo-controlled parallel group study, 37 lean HIV-positive subjects aged 19-50 years were treated with 8 mg/day rosiglitazone (n=20) or placebo (n=17) for 6 months. Insulin sensitivity was estimated from the homeostasis model assessment (HOMA) index. Fasting visfatin, RBP-4, leptin, and adiponectin plasma concentrations were analyzed by immunoassays. Rosiglitazone had no effect on impaired insulin sensitivity, but increased median plasma visfatin from 6.2 ng/ml (95% CI: 5.9; 6.5) to 13.7 ng/ml (12.6; 19.1) (P<0.001) and adiponectin from 3.2 ng/ml (2.2; 4.0) to 4.0 ng/ml (3.3; 8.5; P<0.001). RBP-4 was lowered from 21.0 ng/ml (19.6; 23.1) to 16.3 ng/ml (15.2; 17.0; P<0.001), and leptin concentrations were unchanged. Adipocytokine concentrations were stable in subjects receiving placebo, where a deterioration in insulin sensitivity was detectable (P<0.05). Changes in visfatin and RBP-4 were correlated in subjects receiving rosiglitazone (r=-0.64, P<0.01) but not placebo (r=0.12, P=0.15). TZD treatment affects circulating adipocytokine concentrations in subjects with HIV. Reductions in RBP-4 and increases in visfatin may contribute to the pharmacodynamic action of TZD on glucose homeostasis. Quantification of adipocytokines might be useful to assess TZD treatment effectiveness in insulin-resistant subjects with HIV.

Free fatty acids do not acutely increase asymmetrical dimethylarginine concentrations.

Concentrations of asymmetrical dimethylarginine (ADMA) and free fatty acids (FFAs) are elevated in insulin resistance which is associated with impaired vascular function. We hypothesized that FFAs could alter vascular tone by affecting ADMA concentrations. Plasma FFA levels were increased in seventeen healthy male volunteers by Intralipid/heparin infusion; hemodynamic and biochemical parameters were measured after 90 minutes. Plasma collected before and during Intralipid/heparin or equivalent synthetic FFAs was incubated with human umbilical vein endothelial cells (HUVECs) in vitro. Intralipid/heparin infusion resulted in an approximately seven-fold increase in plasma FFA levels to 1861 +/- 139 micromol/l, which was paralleled by increased systemic blood pressure and forearm blood flow. Intralipid/heparin did not affect ADMA (baseline mean 0.59 [95 % confidence interval [CI]: 0.54; 0.64] and 0.56 [CI: 0.51; 0.59] after 90 minutes), but slightly decreased SDMA (from 0.76, [CI: 0.70; 0.83] to 0.71 [CI: 0.64; 0.74], p < 0.05), and had no effect on ADMA/SDMA ratio. There was no correlation between ADMA and FFA concentrations or forearm blood flow. Incubation of HUVECs with FFA-rich plasma or synthetic FFAs induced an ADMA release after 24 hours, but not after 90 minutes. Acutely increased FFA levels caused hemodynamic effects but did not affect ADMA. Prolonged elevation of FFA levels might influence vascular function by increasing ADMA levels.

High prevalence of abnormal circadian blood pressure regulation and impaired glucose tolerance in adults with hypopituitarism.

Patients with hypopituitarism have an increased mortality from cardiovascular events. Reduced nocturnal blood pressure decline (non-dipping) and impaired glucose tolerance are considered as cardiovascular risk factors. To evaluate the role of these risk factors in patients with hypopituitarism we determined the 24-hour blood pressure regulation and glucose tolerance status in hypopituitary patients with and without growth hormone (GH) deficiency. Sixty-one hypopituitary subjects 5 +/- 3 years after brain surgery because of macroadenoma, 61 patients with type 2 diabetes mellitus (T2DM), and 20 healthy controls were included. Forty-four hypopituitary patients were GH deficient and 28 of these on GH treatment. Non-dipping was observed in 41 % (n = 7) of hypopituitary subjects with normal GH release, in 46 % (n = 13) of patients on GH therapy, and in 69 % (n = 11) of untreated GH deficient patients. Untreated GH deficient patients had a higher systolic night/day ratio (1.00 +/- 0.03) compared to non GH deficient (0.92 +/- 0.02; p < 0.02) and GH treated hypopituitary patients (0.93 +/- 0.01; p < 0.02). The rate of non-dipping in hypopituitarism was comparable to that in T2DM. Pathologic glucose tolerance was diagnosed in 30 % of the hypopituitary patients. The prevalence of non-dipping was independent of glucose metabolism in hypopituitary patients. All controls had normal night time blood pressure fall and glucose metabolism. The high prevalence of nocturnal non-dipping and glucose intolerance detected in this cohort might contribute to the increased cardiovascular risk of hypopituitary patients.

Circulating ADMA concentrations are elevated in hypopituitary adults with and without growth hormone deficiency.

BACKGROUND: Cardiovascular mortality is increased in patients with hypopituitarism. Elevated concentrations of the endogenous NO synthase antagonist asymmetrical dimethylarginine (ADMA) may be related to the development of atherosclerosis and are associated with cardiovascular risk. We studied the concentrations of ADMA in hypopituitary patients with and without growth hormone deficiency (GHD) and in healthy subjects. MATERIALS AND METHODS: Plasma from 44 patients with hypopituitarism with (n = 30) and without GHD (n = 14) and from 25 age- and sex-matched healthy controls was taken for analysis of L-arginine, ADMA, symmetrical dimethylarginine (SDMA) and clinical parameters. Further plasma from 10 hypopituitary patients was examined before and after treatment with 9 g of oral L-arginine for 14 days. RESULTS: Asymmetrical dimethylarginine was significantly higher in the hypopituitary patients than in the controls (0.63 +/- 0.12 vs. 0.51 +/- 0.15 micromol L(-1); P < 0.005). L-arginine and the L-arginine/ADMA ratios were lower in the subjects with hypopituitarism (53 +/- 18 vs. 90 +/- 29 micromol L(-1) and 87 +/- 31 vs. 185 +/- 59; both P < 0.0001). Symmetrical dimethylarginine was comparable between the patients and the controls. L-arginine and dimethylarginines were associated with 2-h stimulated glucose levels in a glucose tolerance test (r = 0.33; P < 0.05), but not other cardiovascular risk factors. Oral L-arginine supplementation normalized the reduced L-arginine/ADMA ratio in the hypopituitary patients. CONCLUSION: Asymmetrical dimethylarginine is elevated in patients with hypopituitarism independent of GHD and traditional risk factors. This might contribute to the increased cardiovascular morbidity in hypopituitary patients.

Effect of systemic vitamin C on free fatty acid-induced lipid peroxidation.

OBJECTIVES: Plasma malondialdehyde (MDA), a reactive product of lipid peroxidation, may be influenced by anti-oxidant therapy. The aim of the present study was to investigate if elevated MDA as induced by increased free fatty acids (FFA) correlates with endothelial function and is affected by high doses of vitamin C. METHODS: The study design was randomised, placebo-controlled, double blind, 2-way cross over. Plasma MDA concentrations and forearm blood flow (FBF) responses to intra-arterial acetylcholine (ACh) and glyceryl trinitrate were assessed during co-administration of vitamin C or placebo in the presence of increased plasma FFA by Intralipid/heparin infusion in 10 healthy male subjects. RESULTS: The seven-fold rise in plasma FFA was associated with an increase in plasma MDA concentrations (r=0.7, p<0.001) and decreased FBF responses to ACh (r=-0.4, p<0.01). Co-administration of vitamin C restored the impaired reactivity of FBF to ACh but had no effect on elevated MDA concentrations. CONCLUSIONS: Anti-oxidant vitamin C improves lipid-induced impairment of endothelium-dependent vasodilation, but does not alter MDA formation or breakdown.

Marked increase in vascular endothelial growth factor concentrations during Escherichia coli endotoxin-induced acute inflammation in humans.

BACKGROUND: Bacterial endotoxins can induce the synthesis and release of vascular endothelial growth factor (VEGF), which may alter vascular permeability and cause vascular leakage. MATERIALS AND METHODS: The effect of acute systemic inflammation on VEGF concentration was measured in healthy males after an intravenous bolus infusion of Escherichia coli endotoxin (lipopolysaccharide, LPS, 20 IU kg-1) in a double-blind, placebo-controlled parallel group study. LPS administration was followed by an infusion of lepirudin (bolus 0.1 mg kg-1, continuous infusion of 0.1 mg kg-1 h-1, n = 12) or saline (n = 12). RESULTS: Plasma VEGF increased from a mean of 15.1 pg mL-1 to 74.6 pg mL-1 5 h after LPS (P < 0.003). Body temperature, pulse rate, leukcytes, prothrombin fragment 1 + 2 (F1 + 2) and lactoferrin increased and platelets decreased after LPS (P < 0.05). The LPS-induced increase in VEGF was paralleled by the neutrophil cell degranulation marker lactoferrin but not by F1 + 2, and was not affected by lepirudin, which blunted F1 + 2 formation (P < 0.05). CONCLUSIONS: Inflammation-induced activation of leukcytes rather than platelets plays a role in the marked increase in VEGF, which cannot be abrogated by antithrombotic therapy.

Circulating concentrations of asymmetrical dimethyl-L-arginine are increased in women with previous gestational diabetes.

AIMS/HYPOTHESIS: The concentration of asymmetrical dimethyl- L-arginine (ADMA), an endogenous inhibitor of the nitric oxide synthase, is increased in patients at risk or with cardiovascular disease. We have investigated ADMA concentrations in women with a history of gestational diabetes (GDM), who could develop endothelial dysfunction and Type II (non-insulin-dependent) diabetes mellitus after delivery, and in healthy control subjects. METHODS: Previous GDM patients were grouped according to their BMI as obese (> or =25 kg/m(2), n=46) or non-adipose (<25 kg/m(2), n=31). Serum samples were taken 14 to 16 weeks after delivery and after 1 year. The control group comprised 17 healthy women (BMI<25 kg/m(2)). ADMA concentrations were analysed by high performance liquid chromatography. RESULTS: ADMA concentrations were comparable between obese and non-adipose GDM patients (0.58+/-0.02 and 0.57+/-0.02 micro mol/l, respectively), and higher than in the control group (0.47+/-0.03 micro mol/l; p<0.006). Insulin resistance as estimated by the insulin sensitivity index was more frequent among the obese than the non-adipose GDM women (p<0.05) and control subjects (p<0.05, both). No change in ADMA concentrations was found after 1 year in women with GDM. There was only a slight correlation between ADMA and BMI (r=0.26, p<0.02), triglycerides (r=0.29, p<0.004), or fasting plasma glucose (r=0.21, p<0.05), and not with the insulin sensitivity index or other parameters. In a multiple regression analysis ADMA serum concentrations were only associated with triglycerides. CONCLUSION/INTERPRETATION: Circulating ADMA concentrations are increased in normoglycaemic women with previous GDM. This increase is independent from other risk factors or surrogate markers for diabetes or cardiovascular events.