Decreased plasma levels of nitric oxide derivatives in obstructive sleep apnoea: response to CPAP therapy

Abstract

BACKGROUND Reduced endothelium dependent vasodilation has been reported in patients with obstructive sleep apnoea (OSA) but direct measurements of the most potent naturally occurring vasodilator, nitric oxide (NO) or its derivatives (nitrate and nitrite, NOx), have not yet been performed in these patients.

METHODS In 21 patients with OSA of mean (SE) age 54 (2) years, body mass index (BMI) 30.9 (1.1) kg/m2, and apnoea-hypopnoea index (AHI) 37 (4)/h, NOx levels were measured in peripheral venous blood samples by chemiluminescence. Blood samples were obtained before and after two nights of continuous positive airway pressure (CPAP) and after 5.5 (1.5) months of follow up. Thirteen age matched, healthy volunteers and 18 patients without OSA but with a similar spectrum of comorbidity served as controls (control groups 1 and 2).

RESULTS Before CPAP NOx levels were 21.7 (1.5) μM in patients with OSA compared with 42.6 (2.2) μM and 36.7 (1.7) μM in control groups 1 and 2, respectively (p<0.01 for each comparison). NOxconcentrations increased to 32.1 (2.7) μM after two nights of CPAP and remained constant at 32.9 (2.3) μM at follow up (p<0.01 compared with levels before CPAP).

CONCLUSIONS Plasma NOx levels are reduced in OSA and can be increased by short and long term CPAP therapy. Although the precise mechanism underlying this observation remains to be clarified, it may have important implications for the development of cardiovascular disease in patients with OSA and for the life saving effect of CPAP.

Reduced Plasma Concentrations of Nitrogen Oxide in Individuals With Essential Hypertension

Koichi Node; Masafumi Kitakaze; Hiromichi Yoshikawa; Hiroaki Kosaka; Masatsugu Hori

From the First Department of Medicine (K.N., M.K., M.H.) and the Department of Physiology (H.K.), Osaka University School of Medicine; and the Sumitomo Life Multiphasic Health Test System (H.Y.), Osaka, Japan.

Abstract Patients with essential hypertension exhibit blunted endothelium-dependent vasodilator responses, which may be largely attributable to reduced bioactivity of nitric oxide (NO). Therefore, we measured the end product of NO, nitrate plus nitrite (nitrogen oxide), and examined the relationship between the degree of hypertension and plasma nitrate plus nitrite levels in patients with essential hypertension. The combined plasma concentration of nitrate plus nitrite, end products of NO metabolism, was reduced in individuals with essential hypertension relative to that in control subjects (15.7±1.1 versus 22.8±1.4 mmol · L-1, P<.001); individuals with borderline hypertension showed values that were intermediate between those of the other two groups (18.2±1.2 mmol · L-1, P<.001). The plasma nitrogen oxide concentration showed significant inverse correlations with both systolic and diastolic blood pressures. The basal concentration of nitrogen oxide in the plasma was reduced, at least in the peripheral circulation, in individuals with essential hypertension.

Metabolic biomarkers of increased oxidative stress and impaired methylation capacity in children with autism

Abstract

BACKGROUND:

Autism is a complex neurodevelopmental disorder that usually presents in early childhood and that is thought to be influenced by genetic and environmental factors. Although abnormal metabolism of methionine and homocysteine has been associated with other neurologic diseases, these pathways have not been evaluated in persons with autism.

OBJECTIVE:

The purpose of this study was to evaluate plasma concentrations of metabolites in the methionine transmethylation and transsulfuration pathways in children diagnosed with autism.

DESIGN:

Plasma concentrations of methionine, S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), adenosine, homocysteine, cystathionine, cysteine, and oxidized and reduced glutathione were measured in 20 children with autism and in 33 control children. On the basis of the abnormal metabolic profile, a targeted nutritional intervention trial with folinic acid, betaine, and methylcobalamin was initiated in a subset of the autistic children.

RESULTS:

Relative to the control children, the children with autism had significantly lower baseline plasma concentrations of methionine, SAM, homocysteine, cystathionine, cysteine, and total glutathione and significantly higher concentrations of SAH, adenosine, and oxidized glutathione. This metabolic profile is consistent with impaired capacity for methylation (significantly lower ratio of SAM to SAH) and increased oxidative stress (significantly lower redox ratio of reduced glutathione to oxidized glutathione) in children with autism. The intervention trial was effective in normalizing the metabolic imbalance in the autistic children.

CONCLUSIONS:

An increased vulnerability to oxidative stress and a decreased capacity for methylation may contribute to the development and clinical manifestation of autism.

Broccoli sprouts: An exceptionally rich source of inducers of enzymes that protect against chemical carcinogens

Induction of phase 2 detoxication enzymes [e.g., glutathione transferases, epoxide hydrolase, NAD(P)H: quinone reductase, and glucuronosyltransferases] is a powerful strategy for achieving protection against carcinogenesis, mutagenesis, and other forms of toxicity of electrophiles and reactive forms of oxygen. Since consumption of large quantities of fruit and vegetables is associated with a striking reduction in the risk of developing a variety of malignancies, it is of interest that a number of edible plants contain substantial quantities of compounds that regulate mammalian enzymes of xenobiotic metabolism. Thus, edible plants belonging to the family Cruciferae and genus Brassica (e.g., broccoli and cauliflower) contain substantial quantities of isothiocyanates (mostly in the form of their glucosinolate precursors) some of which (e.g., sulforaphane or 4-methylsulfinylbutyl isothiocyanate) are very potent inducers of phase 2 enzymes. Unexpectedly, 3-day-old sprouts of cultivars of certain crucifers including broccoli and cauliflower contain 10–100 times higher levels of glucoraphanin (the glucosinolate of sulforaphane) than do the corresponding mature plants. Glucosinolates and isothiocyanates can be efficiently extracted from plants, without hydrolysis of glucosinolates by myrosinase, by homogenization in a mixture of equal volumes of dimethyl sulfoxide, dimethylformamide, and acetonitrile at −50°C. Extracts of 3-day-old broccoli sprouts (containing either glucoraphanin or sulforaphane as the principal enzyme inducer) were highly effective in reducing the incidence, multiplicity, and rate of development of mammary tumors in dimethylbenz(a)anthracene-treated rats. Notably, sprouts of many broccoli cultivars contain negligible quantities of indole glucosinolates, which predominate in the mature vegetable and may give rise to degradation products (e.g., indole-3-carbinol) that can enhance tumorigenesis. Hence, small quantities of crucifer sprouts may protect against the risk of cancer as effectively as much larger quantities of mature vegetables of the same variety.

Muscles and their myokines

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Influence of acupuncture on the pregnancy rate in patients who undergo assisted reproduction therapy.

To evaluate the effect of acupuncture on the pregnancy rate in assisted reproduction therapy (ART) by comparing a group of patients receiving acupuncture treatment shortly before and after embryo transfer with a control group receiving no acupuncture.

DESIGN:
Prospective randomized study.

SETTING:
Fertility center.

PATIENT(S):
After giving informed consent, 160 patients who were undergoing ART and who had good quality embryos were divided into the following two groups through random selection: embryo transfer with acupuncture (n = 80) and embryo transfer without acupuncture (n = 80).

INTERVENTION(S):
Acupuncture was performed in 80 patients 25 minutes before and after embryo transfer. In the control group, embryos were transferred without any supportive therapy.

MAIN OUTCOME MEASURE(S):
Clinical pregnancy was defined as the presence of a fetal sac during an ultrasound examination 6 weeks after embryo transfer.

RESULT(S):
Clinical pregnancies were documented in 34 of 80 patients (42.5%) in the acupuncture group, whereas pregnancy rate was only 26.3% (21 out of 80 patients) in the control group.

CONCLUSION(S):
Acupuncture seems to be a useful tool for improving pregnancy rate after ART.

Effects of silybum marianum on patients with chronic hepatitis C.

BACKGROUND:

Silymarin derived from silybum marianum (milk thistle), a flowering member of the daisy family, may benefit liver function in people infected with the hepatitis C virus. The aims of this pilot study were to assess the efficacy and safety of silymarin on serum hepatitis C virus (HCV) RNA, serum aminotransferases (ALT, AST) levels, liver fibrosis and well-being in patients with chronic hepatitis C (CHC).

METHODS:

This prospective self-controlled trial study was conducted from March to September 2006 at Department of Gastroenterology, Isfahan University of Medical Sciences, Isfahan, Iran. 55 patients with HCV (10 female and 45 male) with a mean age of 31.8 ± 6.4 years (10-67 years) were participated in the study. Patients received 24 weeks of silymarin (630 mg/day). Baseline virological biochemical, liver fibrosis (by a serum fibrosis markers, including YKL-40 and Hyaluronic acid), and SF-36 questionnaire were performed with biochemical tests repeated at the end of the treatment period.

RESULTS:
There was statistically difference in mean of ALT (108.7 ± 86.6 vs 70.3 ± 57.7) before and after the treatment (p < 0.001). The means of AST were 99.4 ± 139.7 and 59.7 ± 64.32 before and after the treatment with statistically differences (p = 0.004). After the treatment, nine patients were found with negative HCV-RNA (p = 0.004) and statistically significant improvement in results of liver fibrosis markers were found only in fibrosis group (p = 0.015). Quality of life was improved significantly (p < 0.001). CONCLUSIONS:
This study indicated that in patients with CHC performing silymarin (650 mg/day) for 6 months, improved serum HCV-RNA titer, serum aminotransferases (ALT, AST), hepatic fibrosis and patient’s quality of life. More future studies are warranted.

Multiple effects of silymarin on the hepatitis C virus lifecycle.

Silymarin, an extract from milk thistle (Silybum marianum), and its purified flavonolignans have been recently shown to inhibit hepatitis C virus (HCV) infection, both in vitro and in vivo. In the current study, we further characterized silymarin’s antiviral actions. Silymarin had antiviral effects against hepatitis C virus cell culture (HCVcc) infection that included inhibition of virus entry, RNA and protein expression, and infectious virus production. Silymarin did not block HCVcc binding to cells but inhibited the entry of several viral pseudoparticles (pp), and fusion of HCVpp with liposomes. Silymarin but not silibinin inhibited genotype 2a NS5B RNA-dependent RNA polymerase (RdRp) activity at concentrations 5 to 10 times higher than required for anti-HCVcc effects. Furthermore, silymarin had inefficient activity on the genotype 1b BK and four 1b RDRPs derived from HCV-infected patients. Moreover, silymarin did not inhibit HCV replication in five independent genotype 1a, 1b, and 2a replicon cell lines that did not produce infectious virus. Silymarin inhibited microsomal triglyceride transfer protein activity, apolipoprotein B secretion, and infectious virion production into culture supernatants. Silymarin also blocked cell-to-cell spread of virus. CONCLUSION: Although inhibition of in vitro NS5B polymerase activity is demonstrable, the mechanisms of silymarin’s antiviral action appear to include blocking of virus entry and transmission, possibly by targeting the host cell.

Grape seed proanthocyanidin extract ameliorates monosodium iodoacetate-induced osteoarthritis

Source
Department of Internal Medicine, Bucheon St. Mary’s Hospital, Korea.

Abstract
Osteoarthritis (OA) is an age-related joint disease that is characterized by degeneration of articular cartilage and chronic pain. Oxidative stress is considered one of the pathophysiological factors in the progression of OA. We investigated the effects of grape seed proanthocyanidin extract (GSPE), which is an antioxidant, on monosodium iodoacetate (MIA)-induced arthritis of the knee joint of rat, which is an animal model of human OA. GSPE (100 mg/kg or 300 mg/kg) or saline was given orally three times per week for 4 weeks after the MIA injection. Pain was measured using the paw withdrawal latency (PWL), the paw withdrawal threshold (PWT) and the hind limb weight bearing ability. Joint damage was assessed using histological and microscopic analysis and microcomputerized tomography. Matrix metalloproteinase-13 (MMP13) and nitrotyrosine were detected using immunohistochemistry. Administration of GSPE to the MIA-treated rats significantly increased the PWL and PWT and this resulted in recovery of hind paw weight distribution (P < 0.05). GSPE reduced the loss of chondrocytes and proteoglycan, the production of MMP13, nitrotyrosine and IL-1β and the formation of osteophytes, and it reduced the number of subchondral bone fractures in the MIA-treated rats. These results indicate that GSPE is antinociceptive and it is protective against joint damage in the MIA-treated rat model of OA. GSPE could open up novel avenues for the treatment of OA.