Prevalence and clinical impact of alcohol withdrawal syndrome in alcohol-associated hepatitis and the potential role of prophylaxis: a multinational, retrospective cohort study.

Background: The prevalence and impact of alcohol withdrawal syndrome (AWS) in patients with alcohol-associated hepatitis (AH) are unknown. In this study, we aimed to investigate the prevalence, predictors, management, and clinical impact of AWS in patients hospitalized with AH. Methods: A multinational, retrospective cohort study enrolling patients hospitalized with AH at 5 medical centres in Spain and in the USA was performed between January 1st, 2016 to January 31st, 2021. Data were retrospectively retrieved from electronic health records. Diagnosis of AWS was based on clinical criteria and use of sedatives to control AWS symptoms. The primary outcome was mortality. Multivariable models controlling for demographic variables and disease severity were performed to determine predictors of AWS (adjusted odds ratio [OR]) and the impact of AWS condition and management on clinical outcomes (adjusted hazard ratio [HR]). Findings: In total, 432 patients were included. The median MELD score at admission was 21.9 (18.3-27.3). The overall prevalence of AWS was 32%. Lower platelet levels (OR = 1.61, 95% CI 1.05-2.48) and previous history of AWS (OR = 2.09, 95% CI 1.31-3.33) were associated with a higher rate of incident AWS, whereas the use of prophylaxis decreased the risk (OR = 0.58, 95% CI 0.36-0.93). The use of intravenous benzodiazepines (HR = 2.18, 95% CI 1.02-4.64) and phenobarbital (HR = 2.99, 95% CI 1.07-8.37) for AWS treatment were independently associated with a higher mortality. The development of AWS increased the rate of infections (OR = 2.24, 95% CI 1.44-3.49), the need for mechanical ventilation (OR = 2.49, 95% CI 1.38-4.49), and ICU admission (OR = 1.96, 95% CI 1.19-3.23). Finally, AWS was associated with higher 28-day (HR = 2.31, 95% CI 1.40-3.82), 90-day (HR = 1.78, 95% CI 1.18-2.69), and 180-day mortality (HR = 1.54, 95% CI 1.06-2.24). Interpretation: AWS commonly occurs in patients hospitalized with AH and complicates the hospitalization course. Routine prophylaxis is associated with a lower prevalence of AWS. Prospective studies should determine diagnostic criteria and prophylaxis regimens for AWS management in patients with AH. Funding: This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Caustic Ingestion: A Risk-Based Algorithm.

INTRODUCTION: Caustic ingestion management could be improved with a diagnostic approach based on risk factors. This study aimed to develop an algorithm derived from predictive factors of a poor clinical course, to evaluate its diagnostic accuracy and resource consumption, and to compare it with 2 other approaches, a radiological one based on computed tomography and a classical one based on symptoms and endoscopy. METHODS: All patients older than 15 years presenting with caustic ingestion in our tertiary care hospital between 1995 and 2021 were prospectively included. Adverse outcome was defined as intensive care unit admission, emergency surgery, or death. Ingestion characteristics, symptoms, and laboratory and endoscopic findings were analyzed to determine the most relevant risk factors. Diagnostic accuracy and the number of examinations required were estimated and compared with the other 2 algorithms applied to our series. RESULTS: The sample included 532 cases of caustic ingestion, 13.2% (95% confidence interval [CI]: 10.3-16.0) of which had adverse outcomes. Volume and type of caustic substance; presence of symptoms and pharyngolaryngeal involvement; and neutrophilia, acidosis, and endoscopic injury were combined to develop an algorithm that would provide the highest diagnostic odds ratio (167.2; 95% CI: 71.9-388.7). Following this approach, half of the patients (50.6%; 95% CI: 46.2-55.1) would not require any examination and, overall, the need for endoscopy (20.0%; 95% CI: 16.4-23.5) and computed tomography (16.3%; 95% CI: 13.0-19.5) would be lower than that for the other 2 algorithms. DISCUSSION: A risk-based algorithm could improve caustic ingestion management by maintaining high diagnostic accuracy while reducing diagnostic test requirements.

Serum cholesterol predicts transplant-free survival in cirrhotic patients undergoing transjugular intrahepatic portosystemic shunt.

BACKGROUND: Malnutrition is frequent in patients with cirrhosis and has been associated with poor prognosis. The Model for End-stage Liver Disease (MELD) score was created to predict survival after Transjugular Intrahepatic Porto-systemic Shunt (TIPS) but lacks a nutritional parameter. AIMS: To evaluate the prognostic value of serum cholesterol in patients with cirrhosis undergoing TIPS and to develop a prognostic score to predict survival. METHODS: An explorative cross-sectional study was conducted of cirrhotic patients undergoing TIPS from 2008 until 2019. Exclusion criteria were liver transplantation or hepatocellular carcinoma before TIPS. Risk analysis was used to compare survival according to clinical and analytical data. The diagnostic performance of serum cholesterol added to MELD was evaluated and confirmed in an external validation cohort. RESULTS: The final cohort of 100 patients had a mean MELD score of 14±5 and cholesterol of 122±51 mg/dL. MELD (p < 0,05) and both cholesterol (p < 0,05) and low-density lipoprotein levels (LDL-C) (p < 0,05) were independent predictors of post-TIPS transplant-free survival with an optimal cut-off of 106 mg/dL for serum cholesterol. The combined MELD-cholesterol risk score improved diagnostic accuracy of each parameter separately, and this was confirmed in the external cohort. CONCLUSION: Serum cholesterol and LDL-C are independent predictors of transplant-free survival in cirrhotic patients undergoing TIPS. The MELD-cholesterol score slightly improved prognostic accuracy. LAY SUMMARY: As an objective and easily measured indicator of both nutritional status and hepatic function, serum cholesterol could be useful to predict transplant-free survival in patients with cirrhosis undergoing TIPS. It can enable health care providers to identify high-risk patients and to optimize nutritional status before TIPS.

Transjugular intrahepatic portosystemic shunt reduces hospital care burden in patients with decompensated cirrhosis.

BACKGROUND AND AIMS: Patients with decompensated cirrhosis frequently require hospital admissions, which are associated with worse prognosis. The aim of this study was to analyze the effect of TIPS on the need for hospital care. Secondary objectives were to assess the clinical and biological impact of TIPS and to identify predictors of post-TIPS hospital care. METHODS: An observational, retrospective study of patients with decompensated cirrhosis treated with TIPS from January 2008 until March 2019. Exclusion criteria were TIPS placed for non-cirrhotic portal hypertension (PH) and patients referred from another hospital without prior or subsequent follow-up at our Unit. Hospital care, PH-related complications, and laboratory data were compared before and after TIPS. RESULTS: The final cohort comprised 104 patients (72% male) with a mean age of 60 (± 10) years. Follow-up from first decompensation until TIPS and that from procedure to study completion were 7 (4.2-9.8) and 20 (4.6-35.4) months, respectively. TIPS was indicated mainly for refractory ascites (50%) and variceal bleeding (39%). Hemodynamic and clinical success rates were 97% and 92%, respectively. The number of emergency department visits and hospital admissions decreased after the procedure (p < 0.001). Improvement was seen in MELD and Child-Pugh scores, renal function, hyponatremia, and anemia after TIPS. Variceal bleeding as the indication for TIPS (OR 0.047; 95 CI 0.006-0,39; p < 0.05) together with early creation of the shunt (stage 3 vs 5; p < 0.05) were associated with a reduction in risk of post-TIPS hospital care. CONCLUSION: TIPS is a safe and effective procedure that reduces hospital care burden by improving PH-related complications, hepatic, renal function, hyponatremia, and anemia. Variceal bleeding as the indication and early placement of the device were associated with a reduction in post-TIPS hospital care. These findings support a role for this treatment, predominantly in the early stages of cirrhosis.

Oxidative and Nitrosative Pattern in Circulating Leukocytes of Very Early/Early Hepatocellular Carcinoma Patients.

BACKGROUND/AIM: In chronic liver disease, various immune cell subsets exert pro or anti-tumour effects by releasing reactive oxygen and nitrogen species (ROS, RNS). Here, we evaluated the oxidative and nitrosative pattern in peripheral blood leukocyte subpopulations of early hepatocellular carcinoma (HCC) patients compared with HCC-free cirrhotic patients. MATERIALS AND METHODS: Venous blood samples from 18 HCC-free cirrhotic patients and 17 early stage HCC patients were collected to determine ROS, RNS and reduced glutathione levels in isolated leukocytes analyzed by flow cytometry. RESULTS: Intracellular levels of ROS and glutathione were higher in lymphocytes, monocytes, and neutrophils from HCC patients as well as mitochondrial superoxide in neutrophils and monocytes whereas intracellular levels of nitric oxide were lower in lymphocytes, monocytes, and neutrophils. CONCLUSION: Early HCC alters intracellular levels of ROS and RNS of some circulating leukocytes subsets. This finding may represent a potential area of interest concerning the development of new treatments and prognostic markers.

Neoadjuvant treatment for locally advanced unresectable and borderline resectable pancreatic cancer: oncological outcomes at a single academic centre.

INTRODUCTION: Pancreatic cancer (PC), even in the absence of metastatic disease, has a dismal prognosis. One-third of them are borderline resectable (BRPC) or locally advanced unresectable PC (LAUPC) at diagnosis. There are limited prospective data supporting the best approach on these tumours. Neoadjuvant chemotherapy (ChT) is being increasingly used in this setting. METHODS: This is a retrospective series of consecutive patients staged as BRPC or LAUPC after discussion in the multidisciplinary board (MDB) at an academic centre. All received neoadjuvant ChT, followed by chemoradiation (ChRT) in some cases, and those achieving enough downstaging had a curative-intent surgery. Descriptive data about patient's characteristics, neoadjuvant treatments, toxicities, curative resections, postoperative complications, pathology reports and adjuvant treatment were collected. Overall survival (OS) and progression-free survival was calculated with Kaplan-Meier method and log-rank test. RESULTS: Between August 2011 and July 2019, 49 patients fulfilled the inclusion criteria, and all of them received neoadjuvant ChT. Fluorouracil+folinic acid, irinotecan and oxaliplatin was the most frequently used scheme (77%). The most prevalent grade 3 or 4 toxicities were neutropenia (26.5%), neurotoxicity (12.2%), diarrhoea (8.2%) and nausea (8.2%). 18 patients (36.7%) received ChRT thereafter. In total, 22 patients (44,9%) became potentially resectable and 19 of them had an R0 or R1 pancreatic resection. One was found to be unresectable at surgery and two refused surgery. A vascular resection was required in 7 (35%). No postoperative deaths were observed. Postoperative ChT was given to 12 (66.7%) of resected patients. Median OS of the whole cohort was 24,9 months (95% CI 14.1 to 35.7), with 30.6 months for resected and 13.1 months for non-resected patients, respectively (p<0.001). CONCLUSION: A neoadjuvant approach in BRPC and LAUPC was well tolerated and allowed a curative resection in 38.8% of them with a potential improvement on OS.

Association of elevated serum triglyceride levels with a more severe course of acute pancreatitis: Cohort analysis of 1457 patients.

BACKGROUND: Previous publications have reported an association between hypertriglyceridemia (HTG) and severity of acute pancreatitis, but this relationship remains somewhat controversial. OBJECTIVE: To evaluate the outcome of acute pancreatitis according to serum triglyceride levels on admission. METHODS: Retrospective analysis of prospectively collected data, which included all consecutive cases of acute pancreatitis admitted to a tertiary hospital (January 2002-December 2014). Acute pancreatitis patients were classified into 3 groups based on serum triglyceride levels (mg/dl) measured within 48 h from admission: normal triglycerides-mild HTG (<200); moderate HTG (200-749); severe HTG (≥750). Primary outcomes were the difference in organ failure, pancreatic necrosis, acute peripancreatic collections and mortality among the three groups. RESULTS: A total of 1,457 cases were included: 1,335 with normal-mild HTG, 77 with moderate HTG and 45 with severe HTG. The rates of organ failure (11.2% in normal-mild HTG group, 15.6% in moderate HTG and 20.0% in severe HTG), persistent multiple organ failure (2.5% vs. 5.2% vs. 6.7%), pancreatic necrosis (9.2% vs. 14.3% vs. 26.7%) and acute collections (21.6% vs. 40.3% vs. 55.6%) increased significantly with hypertriglyceridemia severity grades. On multivariate analysis, triglycerides as a quantitative variable, evaluated in increments of 100 mg/dl, was independently associated with organ failure, pancreatic necrosis, acute collections and mortality (p < 0.05). CONCLUSIONS: Elevated serum triglyceride levels are independently associated with a more severe course of pancreatitis. It must be highlighted the elevated frequency of local complications in patients with HTG that increases proportionally and significantly with HTG severity grades.

Effects of asymmetric dimethylarginine on renal arteries in portal hypertension and cirrhosis.

AIM: To evaluate the effects of asymmetric dimethylarginine (ADMA) in renal arteries from portal hypertensive and cirrhotic rats. METHODS: Rat renal arteries from Sham (n = 15), pre-hepatic portal hypertension (PPVL; n = 15) and bile duct ligation and excision-induced cirrhosis (BDL; n = 15) were precontracted with norepinephrine, and additional contractions were induced with ADMA (10-6-10-3 mol/L), an endogenous inhibitor of nitric oxide (NO) synthase. Concentration-response curves to acetylcholine (1 × 10-9-3 × 10-6 mol/L) were determined in precontracted renal artery segments with norepinephrine in the absence and in the presence of ADMA. Kidneys were collected to determine the protein expression and activity of dimethylarginine dimethylaminohydrolase (DDAH), an enzyme that catabolizes ADMA. RESULTS: In renal arteries precontracted with norepinephrine, ADMA caused endothelium-dependent contractions. The pD2 values to ADMA were similar in the Sham and PPVL groups (4.20 ± 0.08 and 4.11 ± 0.09, P > 0.05, respectively), but were lower than those of the BDL group (4.79 ± 0.16, P < 0.05). Acetylcholine-induced endothelium-dependent relaxation that did not differ, in terms of pD2 and maximal relaxation, among the 3 groups studied. Treatment with ADMA (3 × 10-4 mol/L) inhibited acetylcholine-induced relaxation in the 3 groups, but the inhibition was higher (P < 0.05) in the BDL group compared with that for the Sham and PPVL groups. The mRNA and protein expression of DDAH-1 were similar in kidneys from the three groups. Conversely, DDAH-2 expression was increased (P < 0.05) in PPVL and further enhanced (P < 0.05) in the BDL group. However, renal DDAH activity was significantly decreased in the BDL group. CONCLUSION: Cirrhosis increased the inhibitory effect of ADMA on basal- and induced-release of NO in renal arteries, and decreased DDAH activity in the kidney.

Asymmetric dimethylarginine as a mediator of vascular dysfunction in cirrhosis.

Cirrhosis is associated with marked abnormalities in the circulatory function that involve a reduction in systemic vascular resistance. An important cause of this vasodilatation is the increased production or activity of nitric oxide (NO) in the splanchnic circulation. During portal hypertension and cirrhosis an increased endothelial NO synthase (eNOS) activity is demonstrated in splanchnic vessels. In contrast, the activity of eNOS in the cirrhotic liver is decreased, which suggests a different regulation of eNOS in the liver and in the splanchnic vessels. Asymmetric dimethylarginine (ADMA) is an endogenous NO inhibitor and higher plasma levels of ADMA are related to increased cardiovascular risk in both the general population and among patients with cirrhosis. It has been demonstrated that the liver is a key player in the metabolism of ADMA. This observation was further supported by investigations in human patients, showing a close correlation between ADMA plasma levels and the degree of hepatic dysfunction. ADMA is degraded to citrulline and dimethylamine by dimethylarginine dimethylaminohydrolases (DDAHs). DDAHs are expressed as type 1 and 2 isoforms and are widely distributed in various organs and tissues, including the liver. In this review, we discuss experimental and clinical data that document the effects of dimethylarginines on vascular function in cirrhosis. Our increasing understanding of the routes of synthesis and metabolism of methylarginines is beginning to provide insights into novel mechanisms of liver disease and allowing us to identify potential therapeutic opportunities.

Basal release of nitric oxide in the mesenteric artery in portal hypertension and cirrhosis: role of dimethylarginine dimethylaminohydrolase.

BACKGROUND AND AIM: Increased basal release of nitric oxide (NO) in the splanchnic circulation contributes to elevated plasma levels of NO observed in decompensated cirrhosis. We evaluated in rat mesenteric arteries whether the differences in basal release of NO, revealed by asymmetric dimethylarginine (ADMA)- and N(G) -nitro-L-arginine methyl ester (L-NAME)-induced contractions, were associated with changes in messenger RNA (mRNA) expression of endothelial NO synthase (eNOS) and dimethylarginine dimethylaminohydrolases (DDAHs). METHODS: Rat small mesenteric arteries from 14 Sham-control, from 14 with partial portal vein ligation (PPVL), and from 14 with bile duct excision (BDE)-induced cirrhosis were precontracted under isometric conditions with norepinephrine, and additional contractions were induced with ADMA and L-NAME. mRNA expression of eNOS, DDAH-1, and DDAH-2 in mesenteric arteries were evaluated by real-time polymerase chain reaction. RESULTS: ADMA and L-NAME caused concentration- and endothelium-dependent contractions. pD2 values to L-NAME were similar in all groups. In contrast, pD2 values to ADMA were similar in PPVL and BDE but were significantly lower than those of the L-NAME and the Sham groups. Relaxation to acetylcholine was not modified by ADMA or L-NAME but was abolished by charybdotoxin plus apamin. There was an increased mRNA expression of eNOS, DDAH-1, and DDAH-2 in mesenteric arteries from PPVL and BDE compared with the Sham group. CONCLUSION: Basal release of NO is increased in mesenteric arteries of PPVL and BDE rats. The rise in expression of DDAHs indicates a higher degradation of ADMA. This would result in an increased generation of endothelial NO and mesenteric vasodilation.

Unchanged plasma levels of dimethylarginines and nitric oxide in chronic hepatitis C.

OBJECTIVE: Previous studies have shown that asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA) and nitric oxide (NO) play a prominent role in liver dysfunction. The objective of this study was to determine whether plasma levels of ADMA, SDMA and NO are altered in patients with chronic hepatitis C. MATERIAL AND METHODS: Plasma levels of ADMA, SDMA and NO (nitrite plus nitrate) were measured in 22 patients with chronic hepatitis C and 24 patients with sustained virologic response after treatment with peginterferon plus ribavirin. Seven healthy volunteers served as controls. RESULTS: Plasma levels of ADMA, SDMA and NO were not significantly different between groups: chronic hepatitis C, ADMA 0.55+/-0.06, SDMA 0.22+/-0.03, NO 36.3+/-5.9 micromol/l; treated patients, ADMA 0.60+/-0.15, SDMA 0.31+/-0.05, NO 36.1+/-5.5 micromol/l; controls, ADMA 0.65+/-0.08, SDMA 0.28+/-0.05, NO 40.7+/-8.9 micromol/l). CONCLUSIONS: Our results show that plasma NO, ADMA and SDMA concentrations are not changed in patients with chronic hepatitis C without superimposed signs of acute inflammatory activity. Furthermore, no significant differences in plasma values of NO and dimethylarginines were observed between the group of untreated patients and the group of patients treated with interferon plus ribavirin.

Contractile hyporesponsiveness to norepinephrine of forearm veins in chronic renal failure.

BACKGROUND: We recently reported that endothelium-dependent relaxation is impaired in forearm veins from patients with chronic renal failure. However, assessment of responses to norepinephrine remains controversial. We examined the contractile response to norepinephrine in forearm veins from patients on chronic hemodialysis and the role of nitric oxide (NO), prostanoids, and Ca(2+)-activated K(+) channels in this response. METHODS: Isometric contraction curves were obtained in rings of forearm vein from 21 dialyzed patients and 12 multiorgan donors in response to norepinephrine (1 nmol/L to 10 micromol/L) or KCl (5 to 100 mmol/L). RESULTS: Veins from uremic patients were markedly less responsive to norepinephrine (7.6 +/- 0.6 g) and KCl (6.0 +/- 0.3 g) than those from organ donors (12.0 +/- 0.7 g and 10.4 +/- 0.5 g, respectively, P < .05). Treatment with N(G)-monomethyl-l-arginine (100 micromol/L), an inhibitor of NO synthase, or indomethacin (10 micromol/L), an inhibitor of prostacyclin synthesis, increased the response to norepinephrine in veins from control subjects but not in veins from dialyzed patients. Additional blockade of Ca(2+)-activated K(+) channels did not correct the hyporesponsiveness. In veins incubated in Ca(2+)-free solution containing either 100 mmol/L KCl or 1 micromol/L norepinephrine, addition of calcium chloride (0.1 to 30 mmol/L) elicited contractile responses that were significantly lower in veins from dialyzed patients. CONCLUSIONS: The results demonstrate that norepinephrine-mediated contractions of forearm veins are markedly decreased in dialyzed patients. Endothelium-derived relaxing factors are not involved in this effect. The reduced contractile response is most likely caused by a decreased calcium entry through voltage- and receptor-dependent calcium channels.

Metabolite identification in human liver needle biopsies by high-resolution magic angle spinning 1H NMR spectroscopy.

High-resolution magic angle spinning (HR-MAS) 1H NMR spectroscopy of intact human liver needle biopsies has not been previously reported. HR-MAS NMR spectra collected on 17 specimens with tissue amounts between approximately 0.5 and 12 mg showed very good spectral resolution and signal-to-noise ratios. One-dimensional 1H spectra revealed many intense signals corresponding to cellular metabolites. In addition, some high molecular weight metabolites, such as glycogen and mobile fatty acids, could be observed in some spectra. Resonance assignments for 22 metabolites were obtained by combining the analysis of three different types of 1D 1H spectral editing, such as T2 filtering or the nuclear Overhauser effect and 2D TOCSY and 13C-HSQC spectra. Biochemical stability of the liver tissue during up to 16 h of magic angle spinning at 277 K was studied. Biochemical trends corresponding to the different pathologies were observed, involving free fragments of lipids among other metabolites. NMR signal intensity ratios can be useful for discrimination among non-pathological, hepatitis C affected and cirrhotic liver tissues. Overall, this work demonstrates the applicability of HR-MAS NMR spectroscopy to the biochemical characterization of needle biopsies of the human liver.

Accumulation of symmetric dimethylarginine in hepatorenal syndrome.

In patients with cirrhosis, nitric oxide (NO), asymmetric dimethylarginine (ADMA), and possibly symmetric dimethylarginine (SDMA) have been linked to the severity of the disease. We investigated whether plasma levels of dimethylarginines and NO are elevated in patients with hepatorenal syndrome (HRS), compared with patients with cirrhosis without renal failure (no-HRS). Plasma levels of NO, ADMA, SDMA, and l-arginine were measured in 11 patients with HRS, seven patients with no-HRS, and six healthy volunteers. SDMA concentration in HRS was higher than in no-HRS and healthy subjects (1.47 +/- 0.25 vs. 0.38 +/- 0.06 and 0.29 +/- 0.04 microM, respectively; P < 0.05). ADMA and NOx concentrations were higher in HRS and no-HRS patients than in healthy subjects (ADMA, 1.20 +/- 0.26, 1.11 +/- 0.1, and 0.53 +/- 0.06 microM, respectively; P < 0.05; NOx, 94 +/- 9.1, 95.5 +/- 9.54, and 37.67 +/- 4.62 microM, respectively; P < 0.05). In patients with HRS there was a positive correlation between serum creatinine and plasma SDMA (r2 =0.765, P < 0.001) but not between serum creatinine and ADMA or NOx. The results suggest that renal dysfunction is a main determinant of elevated SDMA concentration in HRS. Accumulation of ADMA as a result of impaired hepatic removal may be the causative factor initiating renal vasoconstriction and SDMA retention in the kidney.

Plasma concentrations of nitric oxide and asymmetric dimethylarginine in human alcoholic cirrhosis.

BACKGROUND/AIMS: The liver plays a prominent role in the metabolism of asymmetric dimethyl-l-arginine (ADMA), an endogenous inhibitor of nitric oxide (NO) synthase. This study was designed to determine whether plasma levels of ADMA and NO production are altered in patients with compensated and decompensated alcoholic cirrhosis. METHODS: Plasma levels of l-arginine, ADMA, symmetric dimethylarginine (SDMA) and NO (nitrite plus nitrate, NOx) were measured in nine patients with compensated alcoholic cirrhosis (Child-Pugh A) and 11 patients with advanced cirrhosis (Child-Pugh B-C). Seven healthy volunteers served as controls. RESULTS: ADMA and NOx concentrations in decompensated cirrhosis were higher than in the compensated group and control group (ADMA: 1.12+/-0.08 vs. 0.58+/-0.05 and 0.58+/-0.07micromol/l, respectively; P<0.05; NOx 97.90+/-10.27 vs. 37.42+/-3.91 and 40.43+/-5.30micromol/l, respectively; P<0.05). There was a positive correlation between the clinical score of the patients and concentrations of ADMA (r(2)=0.547, P<0.01) and NOx (r(2)=0.689, P<0.01). SDMA and l-arginine levels were not significantly different between the three groups. CONCLUSIONS: The results suggest that hepatocellular damage is a main determinant of elevated ADMA concentration in advanced alcoholic cirrhosis. By inhibiting NO release from vascular endothelium, ADMA might oppose the peripheral vasodilation caused by excessive NO production in severe cirrhosis.

Endothelium-dependent responses in human isolated thyroid arteries from donors.

The functional properties of the endothelium of human thyroid arteries remain unexplored. We investigated the intervention of nitric oxide (NO), prostacyclin (PGI(2)) and endothelium-derived hyperpolarizing factor (EDHF) in the responses to acetylcholine and noradrenaline in isolated thyroid arteries obtained from multi-organ donors. Artery rings were suspended in organ baths for isometric recording of tension. The contribution of NO, PGI(2) and EDHF to endothelium-dependent relaxation was determined by the inhibitory effects of N(G)-monomethyl-L-arginine (L-NMMA), indomethacin, and K(+) channel inhibitors respectively. Acetylcholine induced concentration-dependent relaxation; this effect was not modified by indomethacin and was only partly reduced by L-NMMA, but was abolished in endothelium-denuded rings. The relaxation resistant to indomethacin and L-NMMA was abolished by using either apamin combined with charybdotoxin, ouabain plus barium, or a high-K(+) solution. Noradrenaline induced concentration-dependent contractions which were of greater magnitude in arteries denuded of endothelium or in the presence of L-NMMA. In conclusion, the results indicate that in human thyroid arteries the endothelium significantly modulates responses to acetylcholine and noradrenaline through the release of NO and EDHF. EDHF plays a dominant role in acetylcholine-induced relaxation through activation of Ca(2+)-activated K(+) channels, inwardly rectifying K(+) channels and Na(+)-K(+)-ATPase.

Ca2+-activated K+ channels mediate relaxation of forearm veins in chronic renal failure.

BACKGROUND: In arteries, agonists such as acetylcholine release an endothelium-derived hyperpolarizing factor (EDHF) that is neither nitric oxide nor prostacyclin. OBJECTIVES: To examine the responses to acetylcholine in segments of forearm veins from patients with chronic renal failure who either had never received dialysis or had undergone long-term dialysis, and to determine the contribution of nitric oxide and EDHF to endothelium-dependent relaxation in veins from patients with chronic renal failure. METHODS: Isometric tension was recorded in rings of forearm vein from 34 non-dialysed patients, 27 dialysed patients and 14 multiorgan donors (controls). RESULTS: Relaxation in response to acetylcholine was reduced in veins of non-dialysed and dialysed patients. The inhibitors of nitric oxide synthase NG-monomethyl-l-arginine (l-NMMA) and NG,NG-dimethyl-l-arginine (ADMA) reduced by 50% the maximum relaxation in response to acetylcholine in veins from controls and non-dialysed patients; the remaining relaxation was inhibited by 20 mmol/l KCl or by the K+ channel blockers tetraethylammonium chloride, iberiotoxin, charybdotoxin and the combination of barium plus ouabain, but not by apamin or glibenclamide. Relaxation in veins from dialysed patients was inhibited by K+ channel blockade but not by l-NMMA or ADMA. CONCLUSIONS: The results demonstrate that the endothelium-dependent relaxation in forearm veins from controls and non-dialysed patients is mediated by release of nitric oxide and EDHF. In contrast, the relaxation in veins from dialysed patients is mediated mainly by EDHF. EDHF-induced relaxation involves activation of large-conductance Ca2+-activated K+ channels.