Alma Rus

Lung eNOS and iNOS are Reoxygenation Time-Dependent Upregulated After Acute Hypoxia

Nitric oxide plays a critical role in many physiological and physiopathological processes in the lung. Changes in the NO/NOS (Nitric Oxide/Nitric Oxide Synthase) system after hypoxia situations remain controversial in this organ, so that the aim of this work is to perform a complete study of this system in the hypoxic lung after different reoxygenation times ranging from 0 h to 5 days posthypoxia. This is a novel follow‐up study carried out in Wistar rats submitted for 30 min to acute hypobaric hypoxia. We measured endothelial and inducible NOS (eNOS, iNOS) mRNA and protein expression, location, and in situ NOS activity as well as nitrated protein expression and location. In addition, NO levels were indirectly quantified (NOx) as well as the apoptosis level. Results showed an increase in eNOS mRNA, protein, activity as well as eNOS positive immunostaining at 0 h posthypoxia, coinciding with raised NOx levels. Contrary, iNOS, nitrated protein expression and apoptosis level augmented during the final reoxygenation times. The lung NO/NOS system provokes two responses to the hypoxia/reoxygenation processes: (i) eNOS is responsible of the immediate response, producing NO, which causes vasodilation and bronchodilation, and (ii) iNOS is related to the second late response, which seems to be involved in some of the deleterious consequences that hypoxia induces in the lung. Anat Rec, 2010.

Study of the nitric oxide system in the rat cerebellum during aging

BackgroundThe cerebellum is the neural structure with the highest levels of nitric oxide, a neurotransmitter that has been proposed to play a key role in the brain aging, although knowledge concerning its contribution to cerebellar senescence is still unclear, due mainly to absence of integrative studies that jointly evaluate the main factors involved in its cell production and function. Consequently, in the present study, we investigate the expression, location, and activity of nitric oxide synthase isoenzymes; the protein nitration; and the production of nitric oxide in the cerebellum of adult and old rats.ResultsOur results show no variation in the expression of nitric oxide synthase isoforms with aging, although, we have detected some changes in the cellular distribution pattern of the inducible isoform particularly in the cerebellar nuclei. There is also an increase in nitric oxide synthase activity, as well as greater protein-nitration levels, and maintenance of nitrogen oxides (NOx) levels in the senescent cerebellum.ConclusionsThe nitric oxide/nitric oxide syntahses system suffers from a number of changes, mainly in the inducible nitric oxide synthase distribution and in overall nitric oxide synthases activity in the senescent cerebellum, which result in an increase of the protein nitration. These changes might be related to the oxidative damage detected with aging in the cerebellum.

Does inducible NOS have a protective role against hypoxia/reoxygenation injury in rat heart?

PURPOSE The present study analyzes the role of the nitric oxide (NO) derived from inducible NO synthase (iNOS) under cardiac hypoxia/reoxygenation situations. METHODS For this, we have designed a follow-up study of different parameters of cell and tissue damage in the heart of Wistar rats submitted for 30 min to acute hypobaric hypoxia, with or without prior treatment with the selective iNOS inhibitor N-(3-(aminomethyl)benzyl) acetamidine or 1400W (10 mg/kg). The rats were studied at 0 h, 12 h, and 5 days of reoxygenation, analyzing NO production (NOx), lipid peroxidation, apoptosis, and protein nitration expression and location. This is the first time-course study which analyzes the effects of the iNOS inhibition by 1400W during hypoxia/reoxygenation in the adult rat heart. RESULTS The results show that when 1400W was administered before the hypoxic episode, NOx levels fell, while both the lipid peroxidation level and the percentage of apoptotic cells rose throughout the reoxygenation period. Levels of nitrated proteins expression fell only at 12 h post-hypoxia. CONCLUSIONS The inhibition of iNOS raises the peroxidative and apoptotic level in the hypoxic heart indicating that this isoform may have a protective effect on this organ against hypoxia/reoxygenation injuries, and challenging the conventional wisdom that iNOS is deleterious under these conditions. These findings could help in the design of new treatments based on NO pharmacology against hypoxia/reoxygenation dysfunctions.

Inducible NOS inhibitor 1400W reduces hypoxia/re-oxygenation injury in rat lung

Abstract Nitric oxide (NO•) from inducible NO• synthase (iNOS) has been reported to either protect against, or contribute to, hypoxia/re-oxygenation lung injury. The present work aimed to clarify this double role in the hypoxic lung. With this objective, a follow-up study was made in Wistar rats submitted to hypoxia/re-oxygenation (hypoxia for 30 min; re-oxygenation of 0 h, 48 h, and 5 days), with or without prior treatment with the selective iNOS inhibitor 1400W (10 mg/kg). NO• levels (NOx), lipid peroxidation, apoptosis, and protein nitration were analysed. This is the first time-course study which investigates the effects of 1400W during hypoxia/re-oxygenation in the rat lung. The results showed that the administration of 1400W lowered NOx levels in all the experimental groups. In addition, lipid peroxidation, the percentage of apoptotic cells, and nitrated protein expression fell in the late post-hypoxia period (48 h and 5 days). Our results reveal that the inhibition of iNOS in the hypoxic lung reduced the damage observed before the treatment with 1400W, suggesting that iNOS-derived NO• may exert a negative effect on this organ during hypoxia/re-oxygenation. These findings are notable, since they indicate that any therapeutic strategy aimed at controlling excess generation of NO• from iNOS may be useful in alleviating NO•-mediated adverse effects in hypoxic lungs.

Endothelial NOS-derived nitric oxide prevents injury resulting from reoxygenation in the hypoxic lung

Abstract To date, the role that NO derived from endothelial NO synthase (eNOS) plays in the development of the injuries occurring under hypoxia/reoxygenation (H/R) in the lung remains unknown and thus constitutes the subject of the present work. A follow-up study was conducted in Wistar rats submitted to H/R (hypoxia for 30 min; reoxygenation of 0 h, 48 h and 5 days), with or without prior treatment using the eNOS inhibitor L-NIO (20 mg/kg). Lipid peroxidation, apoptosis, protein nitration and NO production (NOx) were analysed. The results showed that L-NIO administration lowered NOx levels in all the experimental groups. Contrarily, the lipid peroxidation level and the percentage of apoptotic cells rose, implying that eNOS-derived NO may have a protective effect against the injuries occurring during H/R in the lung. These findings could open the possibility of future studies to design new therapies for this type of hypoxia based on NO-pharmacology.

Nitric Oxide, Inflammation, Lipid Profile, and Cortisol in Normal- and Overweight Women With Fibromyalgia

Objectives: Research has identified many factors associated with fibromyalgia (FM), but findings have been inconsistent. This study aimed to investigate changes in levels of nitric oxide (NO), inflammatory markers, lipid profile, and cortisol in normal- and overweight patients with FM and controls. Since most patients with FM are overweight, we explored possible changes in these markers according to body mass index (BMI). Methods: This preliminary study was performed on serum samples of women with FM and age-matched controls, grouped according to their BMI: 12 normal-weight patients and 12 controls and 13 overweight patients and 8 controls. Ozone-based chemiluminescence assay was used to measure NO. Inflammatory mediators and cortisol were determined by immunoassay. Lipid profile was measured by a spectrophotometric procedure. Functional capacity was assessed by the fibromyalgia impact questionnaire (FIQ). Results: Normal-weight patients showed higher levels of C-reactive protein (CRP) and apolipoprotein B compared to controls (both p < .05). CRP, apolipoprotein B, and triglycerides were higher in overweight patients versus overweight controls (all p < .05) and in overweight versus normal-weight patients (CRP p < .01; apolipoprotein B, triglycerides p < .05). The other markers were unaffected. Apolipoprotein B (r = .762; p < .05) and NO (r = −.921; p < .05) levels correlated with FIQ score in normal-weight patients. CRP level correlated with FIQ (r = .912; p < .05) in overweight patients. Conclusions: CRP and apolipoprotein B, biomarkers linked to cardiovascular events, may be associated with FM-related dysfunction in normal- and overweight women with FM. Their increased levels in these patients may indicate an increased risk of cardiovascular disease.

Nitric oxide averts hypoxia‐induced damage during reoxygenation in rat heart

Nitric oxide (NO), synthesized by the hemoproteins NO synthases (NOS), is known to play important roles in physiological and pathological conditions in the heart, including hypoxia/reoxygenation (H/R). This work investigates the role that endogenous NO plays in the cardiac H/R‐induced injury. A follow‐up study was conducted in Wistar rats subjected to 30 min of hypoxia, with or without prior treatment using the nonselective NOS inhibitor L‐NAME (1.5 mM). The rats were studied at 0 h, 12 h, and 5 days of reoxygenation, analysing parameters of cell, and tissue damage (lipid peroxidation, apoptosis, and protein nitration), as well as in situ NOS activity and NO production (NOx). The results showed that after L‐NAME administration, in situ NOS activity was almost completely eliminated in all the experimental groups, and consequently, NOx levels fell. Contrarily, the lipid peroxidation level and the percentage of apoptotic cells rose throughout the reoxygenation period. These results reveal that NOS inhibition exacerbates the peroxidative and apoptotic damage observed before the treatment with L‐NAME in the hypoxic heart, pointing to a cardioprotective role of NOS‐derived NO against H/R‐induced injury. These findings could open the possibility of future studies to design new therapies for H/R‐dysfunctions based on NO‐pharmacology. Microsc. Res. Tech., 2011.

Endogenous Nitric Oxide Can Act as Beneficial or Deleterious in the Hypoxic Lung Depending on the Reoxygenation Time

Nitric oxide (NO) has been implicated in many pathophysiological situations in the lung, including hypoxia/reoxygenation. This work seeks to clarify the current controversy concerning the double protective/toxic role of endogenous NO under hypoxia/reoxygenation situations in the lung by using a nitric oxide synthase (NOS) inhibitor, in a novel approach to address the problems raised from assaults under such circumstances. A follow‐up study was conducted in Wistar rats submitted to hypoxia/reoxygenation (hypoxia for 30 min; reoxygenation of 0 h, 48 h, and 5 days), with or without prior treatment using the nonselective NOS inhibitor L‐NAME (1.5 mM, in drinking water). Lipid peroxidation, apoptosis level, protein nitration, in situ NOS activity and NO production (NOx) were analyzed. This is the first work to focus on the time‐course effects of L‐NAME in the adult rat lung submitted to hypoxia/reoxygenation. The results showed that after L‐NAME administration, in situ NOS activity was almost completely eliminated and consequently, NOx levels fell. Lipid peroxidation and the percentage of apoptotic cells rose at the earliest reoxygenation time (0 h), but decreased in the later period (48 h and 5 days). Also nitrated protein expression decreased at 48 h and 5 days posthypoxia. These results suggest that NOS‐derived NO exerts two different effects on lung hypoxia/reoxygenation injury depending on the reoxygenation time: NO has a beneficial role just after the hypoxic stimulus and a deleterious effect in the later reoxygenation times. Moreover, we propose that this dual role of NO depends directly on the producer NOS isoform. Anat Rec, 2010.

Effectiveness of Global Postural Re-education for Treatment of Spinal Disorders: A Meta-analysis.

Objective The aim of this study was to investigate the effects of global postural re-education (GPR) on the treatment of spinal disorders by performing a systematic review and a meta-analysis. Design MEDLINE, Scopus, and PEDro databases were searched without language or publication date restrictions. Data on pain and function were used to evaluate the effectiveness of GPR. Randomized controlled trials and controlled clinical trials analyzing the effectiveness of GPR on spinal disorders were selected. The standardized mean difference (SMD) and the corresponding 95% confidence interval (95% CI) were calculated. The meta-analysis was performed using the Comprehensive Meta-analysis 3.3 software. Results Seven randomized controlled trials and 4 controlled clinical trials were included in the meta-analysis. The results showed a medium improvement on pain (SMD = −0.63; 95% CI, −0.43 to −0.83) and function (SMD = −0.48; 95% CI, −0.25 to −0.72) after GPR treatment. The positive effect, which was greater in patients with ankylosing spondylitis followed by low back pain and neck pain, was more significant during the intermediate follow-up than immediately after treatment. Conclusions This meta-analysis provides reliable evidence that GPR may be an effective method for treating spinal disorders by decreasing pain and improving function.

Response of the Nitric Oxide System to Hypobaric Hypoxia in the Aged Striatum

Background: Nitric oxide (NO) appears to play a key role in the hypoxic injury to the brain. We have previously reported that hypoxia/reoxygenation downregulated NO synthases (NOS) in the adult striatum. Until now, no data were available concerning the influence of aging in conjunction with hypoxia/reoxygenation on the NO system in the striatum. Objective: The aim of this study was to assess the role of the NO pathway in the hypoxic aged striatum. Methods: Wistar rats 24-25 months old were submitted to hypobaric hypoxia (20 min)/reoxygenation (0 h, 24 h, 5 days). Expression (PCR, immunohistochemistry/image analysis) and activity (NADPH-diaphorase/image analysis) of NOS isoforms (neuronal NOS or nNOS, endothelial NOS or eNOS, inducible NOS or iNOS) were analyzed together with nitrated protein expression (immunohistochemistry/image analysis). NO levels were indirectly quantified as nitrates/nitrites (NOx). Results: The mRNA levels of NOS isoforms were undetectable at 0 h after hypoxia in the striatum compared to the control. At later reoxygenation times, nNOS mRNA decreased, while eNOS mRNA augmented. Protein levels of nNOS and eNOS rose at 24 h after hypoxia, and iNOS protein increased at 5 days. NOx levels remained unchanged, whereas in situ NOS activity and protein nitration diminished during reoxygenation in the aged striatum. Conclusion: The aged striatum may overexpress NOS isoforms as a neuroprotective-adaptive mechanism to hypoxia. However, this mechanism may not work properly in the aged striatum, since no changes in NO levels were detected after hypoxia. This may be related to the low activity of NOS isoforms in the hypoxic striatum.