Overexpression of human heme oxygenase-1 attenuates endothelial cell sloughing in experimental diabetes

Heme oxygenase (HO)-1 represents a key defense mechanism against oxidative injury. Hyperglycemia produces oxidative stress and various perturbations of cell physiology. The effect of streptozotocin (STZ)-induced diabetes on aortic HO activity, heme content, the number of circulating endothelial cells, and urinary 8-epi-isoprostane PGF2alpha (8-Epi) levels in control rats and rats overexpressing or underexpressing HO-1 was measured. HO activity was decreased in hyperglycemic rats. Hyperglycemia increased urinary 8-Epi, and this increase was augmented in rats underexpressing HO-1 and diminished in rats overexpressing HO-1. The number of detached endothelial cells and O2- formation increased in diabetic rats and in hyperglycemic animals underexpressing HO-1 and decreased in diabetic animals overexpressing HO-1 compared with controls. These data demonstrate that HO-1 gene transfer in hyperglycemic rats brings about a reduction in O2- production and a decrease in endothelial cell sloughing. Upregulation of HO-1 decreases oxidant production and endothelial cell damage and shedding and may attenuate vascular complications in diabetes.     

Oxidative stress implication in a new phenotype of amyotrophic quadricipital syndrome with cardiac involvement due to lamin A/C mutation

This study aimed at evaluating OS in an amyotrophic quadricipital syndrome with cardiac impairment in a family of 80 members with a mutation in lamin A/C gene. Twelve patients had cardiac involvement (5 cardiac and skeletal muscles impairment). OS was evaluated in blood samples (thiobarbituric acid-reactive substances (TBARS), carbonylated proteins (PCO)) 6 “affected patients” with phenotypic and genotypic abnormalities without heart failure and 3 “healthy carrier” patients. OS was higher in affected patients than in healthy, as shown by the higher TBARS and PCO values. Patients with cardiac and peripheral myopathy exhibited a higher OS than patients with only cardiac disease (TBARS: 1.73 ± 0.05 vs. 1.51 ± 0.04 mmol/l (p = 0.051), PCO: 2.73 ± 0.34 vs. 0.90 ± 0.10 nmol/mg protein (p = 0.47)), and with healthy carriers patients (TBARS: 1.73 ± 0.05 vs. 1.16 ± 0.14 mmol/l (p = 0.05), PCO: 2.73 ± 0.34 vs. 0.90 ± 0.20 nmol/mg protein (p = 0.47)).

OS may thus contribute to the degenerative process of this laminopathy. ROS production occurs, prior to heart failure symptoms. We suggest that the extent activation may also promote the variable phenotypic expression of the disease.     

Heme oxygenase metabolites inhibit tubuloglomerular feedback in vivo

Tubuloglomerular feedback (TGF) is a renal autoregulatory mechanism that constricts the afferent arteriole in response to increases in distal NaCl. Heme oxygenases (HO-1 and HO-2) release carbon monoxide (CO) and biliverdin, which may help control renal function. We showed in vitro that HO products inhibit TGF; however, we do not know whether this also occurs in vivo or the mechanism(s) involved. We hypothesized that in vivo HO-1 and HO-2 in the nephron inhibit TGF via release of CO and biliverdin. We first performed laser capture microdissection followed by real-time PCR and found that both HO-1 and HO-2 are expressed in the macula densa. We next performed micropuncture experiments in vivo on individual rat nephrons, adding different compounds to the perfusate, and found that an HO inhibitor, stannous mesoporphyrin (SnMP), potentiated TGF (P < 0.05, SnMP vs. control). The CO-releasing molecule (CORM)-3 partially inhibited TGF at 50 μmol/l (P < 0.01, CORM-3 vs. control) and blocked it completely at higher doses. A soluble guanylyl cyclase (sGC) inhibitor, LY83583, blocked the inhibitory effect of CORM-3 on TGF. Biliverdin also partially inhibited TGF (P < 0.01, biliverdin vs. control), most likely attributable to decreased superoxide (O(2)(-)) because biliverdin was rendered ineffective by tempol, a O(2)(-) dismutase mimetic. We concluded that HO-1 and HO-2 in the nephron inhibit TGF by releasing CO and biliverdin. The inhibitory effect of CO on TGF is mediated by the sGC/cGMP signaling pathway, whereas biliverdin probably acts by reducing O(2)(-).     

Different thermal sensitivity to exercise and cold in men and women

Rectal temperature gain for sweating and shivering was investigated in men (M) and women during exercise and cold exposure. Women, taking and not taking oral contraceptives, were tested during follicular (F) and luteal (L) phases of the menstrual cycle. The gains for sweating (M, 4.85; F, 5.00; L, 12.25 kPa °C⁻¹) and shivering (M, 6.50; F, 2.75; L, 2.00 ml kg min⁻¹ °C⁻¹) differed between sexes, as well as between F and L, and were affected by the oral contraceptives (5.45 and 8.00 kPa °C⁻¹, P<0.01, and 6.00 and 4.25 ml kg min⁻¹ °C⁻¹, P<0.05, respectively).     

Autoantibodies against oxidized LDL are associated with severe chest pain attacks in patients with coronary heart disease

Autoantibodies against oxidized low-density lipoprotein (oxLDL) predict the progression of atherosclerosis. Several studies have shown that oxLDL is present in atherosclerotic lesions and that several factors present in active atherosclerotic plaques can oxidatively modify LDL. Oxidation of LDL induces production of autoantibodies against oxLDL (oxLDLab) that can be measured using an EIA test. Our aim was to see whether oxLDLab are associated with severe chest pain attacks in coronary heart disease (CHD) patients. Patients having two- or three-vessel CHD, as assessed by coronary angiography, and their siblings were recruited into the study (n = 568, mean age 55.8 years, range 29.3–83.2 years). Nondiabetic patients having a history of severe chest pain attacks had significantly higher oxLDLab levels (0.611 ± 0.56) than those who did not have a history of severe chest pain attacks (0.487 ± 0.40) (p = 0.027), even though age, cholesterol level, body mass index, and blood pressure were similar in both groups. However, no difference was found in oxLDLab levels in diabetic patients with or without a history of severe chest pain attacks. Increased levels of oxLDL autoantibodies are associated with severe chest pain attacks in nondiabetic patients with CHD.     

Heme oxygenase-1 prevents superoxide anion-associated endothelial cell sloughing in diabetic rats

Heme oxygenase-1 (HO-1) represents a key defense mechanism against oxidative injury. Hyperglycemia has been linked to increased oxidative stress, leading to endothelial dysfunction, delayed cell replication, and enhanced apoptosis. The effect of streptozotocin (STZ)-induced diabetes on HO activity, HO-1 promoter activity, superoxide anion (O*-2, and the number of circulating endothelial cells was measured. The expression of HO-1/HO-2 protein was unchanged, but HO activity was decreased in aortas of diabetic rats compared with control (p < 0.05). High glucose decreased HO-1 promoter activity (p < 0.05). Hyperglycemia increased O*-2 and this increase was augmented with HO-1 inhibition and diminished with HO-1 upregulation (p < 0.05). Circulating endothelial cells were significantly higher in diabetic rats and were decreased or increased with administration of the HO-1 inducer (CoPP) or inhibitor (SnMP), respectively (p<0.05). In conclusion, HO-1 upregulation in diabetic rats brings about an increase in serum bilirubin, a reduction in O*-2 production, and a decrease in endothelial cell sloughing.     

Heme oxygenase-1 expression levels are cell cycle dependent

Heme oxygenase-1 (HO-1) is a stress protein, which has been suggested to participate in defense mechanisms against agents that may induce oxidative injury, such as angiotensin II (Ang II). The purpose of the present study was to examine the role of human HO-1 in cell-cycle progression. We investigated the effect of Ang II on HO-1 gene expression in serum-deprived media to drive human endothelial cells into G(0)/G(1) (1% FBS) compared to exponentially grown cells (10% FBS). The addition of Ang II (100 ng/ml) to endothelial cells increased HO-1 protein and activity in G(0)/G(1) in a time-dependent manner, reaching a maximum HO-1 level at 16 h. Real-time RT-PCR demonstrated that Ang II increased the levels of HO-1 mRNA in G(0)/G(1) as early as 1 h. The rate of HO-1 induction in response to Ang II was several-fold higher in serum-starved cells compared to cells cultured in continuous 10% FBS. The addition of Ang II increased the generation of 8-epi-isoprostane PGF(2 alpha). Inhibition of HO-1, by Stannis mesoporphyrin (SnMP), potentiated Ang II-mediated DNA damage and generation of 8-epi-isoprostane PGF(2 alpha). These results imply that expression of HO-1 in G(0)/G(1), in the presence of Ang II, may be a key player in attenuating DNA damage during cell-cycle progression. Thus, exposure of endothelial cells to Ang II causes a complex response involving generation of superoxide anion, which may be involved in DNA damage. Upregulation of HO-1 ensures the generation of bilirubin and carbon monoxide (CO) in G(0)/G(1) phase to counteract Ang II-mediated oxidative DNA damage. Inducibility of HO-1 in G(0)/G(1) phase is essential and probably regulated by a complex system involving oxygen species to assure controlled cell growth.     

Early changes in adenosine A1 receptors in cerebral cortex slices submitted to in vitro ischemia.

The effects of brain ischemia on the maximum binding capacity (B_max) and affinity (K_d) of A₁ receptors were studied in the rat cerebral cortex, with an in vitro approach. The results were correlated with changes in ³H-adenosine release, studied under identical experimental conditions. Fifteen minutes of in vitro ‘ischemia’ (hypoxic, glucose-free medium) induced a significant increase in both B_max (2398±132 fmol/mg protein, 151% of the control, P<0.05) and in K_d (2.43±0.12 nM, 161% of the control, P<0.01). At the same time, an increase in tritium efflux from [³H]-adenosine labeled cerebral cortex slices to 324% of the control was observed. A trend toward normalization was evident 5–15 min after ‘reoxygenation’ (restoring normal medium), but the binding parameters were still altered after 60 min (B_max 2110±82 fmol/mg protein, K_d 2.26±0.14 nM, P<0.01 vs the corresponding control) as was adenosine release (196% of the control). These findings suggest that the increased availability of adenosine and its receptors may be a defense mechanism against ischemic injury, while the reduced affinity of A₁ receptors, possibly due to desensitization, may be a sign of ischemia-induced cellular damage.     

Phospholipid hydroperoxide glutathione peroxidase (PHGPx) expression is downregulated in poorly differentiated breast invasive ductal carcinoma

Phospholipid Hydroperoxide Glutathione Peroxidase (PHGPx) is the only known enzyme able to reduce lipid peroxides bound to cell membranes. Moreover it has been involved in apoptosis and can influence intracellular signaling. To investigate the possible relationship between PHGPx and human cancer we have quantified PHGPx expression levels by real-time quantitative PCR and immunohistochemistry in tissue samples of human breast invasive ductal carcinoma from 34 patients compared with their own controls of benign breast tissue. PHGPx expression levels were compared with the clinical and pathological data of these patients. The results showed that PHGPx expression levels are downregulated in poorly differentiated (grade 3) breast invasive ductal carcinoma (P = 0.0043). PHGPx expression levels decreased gradually with tumor grade from grade 1 to grade 3.We also found a downregulation of PHGPx in cases that showed p53 accumulation compared with cases without p53 immunostaining (P = 0.0011). PHGPx was also downregulated in cases without progesterone receptors (PR) immunostaining compared with cases with PR immunostaining (P = 0.0165). Grade 3, p53 immunostaining and absence of PR immunostaining are poor prognostic factors. These results suggest that PHGPx downregulation could be related with a poorer prognosis in breast invasive ductal carcinoma.     

Chromium picolinate supplementation improves insulin sensitivity in Goto-Kakizaki diabetic rats

Chromium picolinate (CrP) supplementation has been studied as a potential therapy of insulin resistance and lipid abnormalities. There have been some reports involving chromium supplementation in patients with diabetes, but the results are varied. The present study was conducted to assess the effects of CrP on insulin sensitivity and body weight in Goto-Kakizaki (GK) diabetic rats. We supplemented normal Sprague-Dawley (SD) rats and GK diabetic rats with supplemental CrP, 100 mg/kg/day once a day for 4 weeks. In the normal SD rats, the mean body weight of the control group increased by 50.5%, whereas that of the CrP-treated group increased by 65.9% (P < 0.05 vs control). Similarly, in the diabetic GK rats, CrP supplementation showed increased weight gain compared to the control group (133.4% vs 119.6% of the baseline weight, P < 0.01). Glucose tolerance tests (GTT) [ip injection of glucose; 2 g/kg] and insulin sensitivity tests [SQ injection of insulin (5 U/kg) plus ip injection of glucose (30 min after insulin injection)] were conducted. During insulin sensitivity tests at the end of treatment, the glucose levels were significantly lower in CrP-treated rats compared with the control rats (AUC_0→120; 113.1 ± 32.0 vs 170.5 ± 49.0 mg-min/mL, P < 0.05). During GTTs, the glucose levels and insulin concentrations in the CrP-treated rats were not different from those in the control rats.

The results of these studies suggest that CrP supplementation in GK diabetic rats leads to increase of weight gain and improvement of insulin sensitivity. This raises the possibility that CrP supplementation can be considered to improve carbohydrate metabolism in patients with type 2 diabetes mellitus.     

Analysis of dihydroethidium fluorescence for the detection of intracellular and extracellular superoxide produced by NADPH oxidase

All methods used for quantitation of superoxide have limitations when it comes to differentiating between extracellular and intracellular sites of superoxide production. In the present study, we monitored dihydroethidium (DHE)-derived fluorescence at 570 nm, which indicates hydroxyethidium derived from reaction with superoxide produced by human leukemia cells (HL-60) and microvascular endothelial cells (HMEC-1). Phorbol-12-myristate 13-acetate (PMA; 100 ng/ml) caused an increase in fluorescence and lucigenin chemiluminescence in HL-60, which was abolished by superoxide dismutase (SOD; 600 U/ml) indicating that DHE detects extracellular superoxide. Furthermore, both HL-60 cells and HMEC-1 generated a fluorescence signal in the presence of DHE under resting conditions, which was unaffected by SOD, but abolished by polyethylene glycosylated-SOD (PEG-SOD) (100 U/ml) and MnTmPyP (25 μM), indicating that DHE also detects superoxide produced intracellularly. In HMEC-1, silencing of either Nox2 or Nox4 components of NADPH oxidase with small interference RNA (siRNA) resulted in a significant reduction in superoxide detected by both DHE fluorescence (Nox2 siRNA; 71 ± 6% and Nox4 siRNA 83 ± 7% of control) and lucigenin chemiluminescence (Nox2; 54 ± 6% and Nox4 74 ± 4% of control). In conclusion, DHE-derived fluorescence at 570 nm is a convenient method for detection of intracellular and extracellular superoxide produced by phagocytic and vascular NADPH oxidase.     

The effects of in vivo and in vitro non-enzymatic glycosylation and glycoxidation on physico-chemical properties of haemoglobin in control and diabetic patients

The erythrocyte deformability, which is related to erythrocyte internal viscosity, was suggested to depend upon the physico-chemical properties of haemoglobin. In the present study we employed ESR spectroscopy in order to explore further the extent to which the in vivo or in vitro glycation and/or glycoxidation might affect haemoglobin structure and conformation. We revealed that under both in vivo and in vitro conditions the attachment of glucose induced a mobilization of thiol groups in the selected domains of haemoglobin molecules (the increased h₊₁/h₀ parameter of maleimide spin label, MSL; 0.377 ± 0.021 in diabetics vs 0.338 ± 0.017 in controls, n = 12, P < 0.0001). The relative rotational correlation time (τ_c) of two spin labels, TEMPONE and TEMPAMINE, respectively, in erythrocyte insides (5.22 ± 0.42 in diabetics, n = 21 vs 4.79 ± 0.38, n = 16 in controls, P < 0.005) and in the solutions of in vitro glycated haemoglobin, were increased. Neither oxidation nor crosslinking of thiol groups was evidenced in glycated and/or oxidized haemoglobin. In addition, erythrocyte deformability was found to be reduced in type 2 diabetic patients (6.71 ± 1.08, n = 28 vs 7.31 ± 0.96, n = 21, P < 0.015). In conclusion, these observations suggest that: the attachment of glucose to haemoglobin might have decreased the mobility of the Lys-adjacent Cys residues, thus leading to the increased h₊₁/h₀ parameter of MSL. Such structural changes in haemoglobin owing to non-enzymatic glycosylation may contribute to the increased viscosity of haemoglobin solutions (r = 0.497, P < 0.0035) and the enhanced internal viscosity of diabetic erythrocytes (r = 0.503, P < 0.003). We argue that such changes in haemoglobin, and consequently in red blood cells, might contribute to the handicapped oxygen release under tissue hypoxia in the diabetic state.     

Efficiency of asbestos shading for growth of Barki rams during hot summer

Twenty-four growing Barki rams, 5–6 months old with an average body weight of 22 kg, were divided into asbestos shaded and unshaded groups during summer. Ad libitum feeding on roughage with 0.5 kg of concentrates per head per day was practiced. Drinking water was available twice daily in the early morning and afternoon. Biweekly observations included rectal temperature (RT; °C), and respiration rate (RR; breaths per minute) at 06:00 h and 14:00 h were recorded. Meteorological data, plasma glucose, calcium, inorganic phosphorus and packed cell volume were also measured. Results indicated that experimental animals developed hyperthermia during June to September, as evidenced by higher (P < 0.01) RT and RR than normal (40 ± 0.05 and 103.9 ± 3.87 vs. 38.9 ± 0.10 and 40 ± 6.56, respectively). Diurnal variations in these physiological phenomena were closely associated (P < 0.05) with ambient temperature changes. As compared with the unshaded group, providing an asbestos shed reduced (P < 0.05) RT and RR in the hyperthermic animals during the day (39.9 ± 0.07 and 94.7 ± 3.75 vs. 40.1 ± 0.08 and 113.1 ± 4.74, respectively), but it increased (P < 0.05) these parameters during summer nights (39.5 ± 0.05 and 82.4 ± 0.95 vs. 39.2 ± 0.07 and 71.6 ± 2.41, respectively). It also increased (P < 0.05) packed cell volume 1 h after morning drinking (35 ± 0.97 vs. 33.2 ± 0.60); reduced (P < 0.05) plasma glucose (43.3 ± 5.88 vs. 53.2 ± 6.31); caused hypocalcemia (10.9 ± 0.35 vs. 11.5 +- 0.43; P < 0.05) and hypophosphatemia (3.9 ±0.35 vs. 4.6 ± 0.34; P < 0.05) as a result of hyperthermia. Monthly variations in all parameters studied were higher (P < 0.01) during early summer. It is concluded that providing an asbestos shed for growing Barki rams under Egyptian summer conditions will not protect the animals from hyperthermia by day and night, as it interferes with extra body heat dissipation to the surroundings during summer nights. Although the unshaded animals were more hyperthermic during summer days, they tended to be normal during the night.     

The effect of follicle-stimulating hormone on follicular development, granulosa cell apoptosis and steroidogenesis and its mediation by insulin-like growth factor-I in the goat ovary

The effect of FSH on goat follicular development, granulosa cell apoptosis and steroidogenesis and its mediation by insulin-like growth factor (IGF)-I were studied through both in vivo and in vitro experiments. The FSH treatment was begun on Day 9 after estrus and consisted of injections twice a day for 3 days in decreasing doses (7.5–7.5–5.0–5.0–2.5–2.5 mg). Does in both treatment and control groups were slaughtered for ovaries on Day 12. Granulosa cell apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). Expression of IGF-I and IGF-II mRNA was determined by RT–PCR, while concentrations of progesterone (P4), estradiol (E2), IGF-I and IGF-II were measured by radioimmunoassay (RIA). Following parameters increased significantly (P<0.05) after the FSH treatment: follicle number (5.0±1.5 versus 9.0±2.0 per ovary), the level of E2 (0.1±0.1 ng/ml versus 0.7±0.2 ng/ml), the E2/P4 ratio (0.7±0.4 versus 4.7±3.0) and the concentrations of IGF-I (0.5±0.2 ng/ml versus 119.4±15.1 ng/ml) and IGF-II (0.12±0.03 ng/ml versus 40.9±18.7 ng/ml) in follicular fluid of the medium sized (3–5 mm) follicles and in the ovarian cortex the relative quantity of IGF-I mRNA (0.37±0.17 versus 0.90±0.12 Max OD). In contrast, the ratio of apoptotic granulosa cells in these follicles was reduced significantly (0.53±0.1 versus 0.10±0.01, P<0.05). In large (>5 mm) follicles, however, only the follicle number (2.3±0.7 versus 7.0±1.5 per ovary) and the level of IGF-I (38.4±11.0 ng/ml versus 87.3±13.9 ng/ml) increased significantly (P<0.05), whereas other values did not change. In vitro culture of granulosa cells showed that FSH significantly (P<0.05) enhanced IGF-I production (12.7±2.1 ng/ml versus 26.±21.9 ng/ml) by these cells, and both FSH and IGF-I reduced the ratios of apoptotic cells (from 0.7±0.07 to 0.3±0.1 and 0.2±0.04, respectively) and the effect was additive when both were used together. H89, the PKA pathway inhibitor, blocked the effect of FSH on granulosa cell apoptosis and IGF-I production in vitro. These results indicated that FSH mainly enhanced the development of medium sized follicles in the goat by suppressing the apoptosis of granulosa cells via increasing production of IGF-I and steroids, possibly through the PKA pathway.     

Nitrotyrosine formation and apoptosis in rat models of ocular injury

This study was performed to examine inducible nitric oxide synthase (NOS-2) expression, nitrotyrosine formation and apoptosis in rats with elevated intraocular pressure (IOP) and/or ocular inflammation. Ocular inflammation was induced via injection of intra-vitreal lipopolysaccharide (LPS) while IOP was elevated by episcleral vessel cauterization. Animals were randomized to one of the following conditions: elevated IOP, LPS, elevated IOP+LPS, and control. Immunohistochemical staining and western blot analysis of retinal lysates revealed NOS-2 and nitrotyrosine immunoreactivity in all disease groups. NOS-2 expression and protein nitration was significantly greater in rats with elevated IOP+LPS compared to elevated IOP, LPS, and control groups. Nitrite levels in the retina affirmed significantly increased levels of nitric oxide generation in LPS-treated rats with elevated IOP (346 ± 23.8 μM) vs LPS-treated, elevated IOP and control groups (195.6 ± 12.6, 130 ± 2.5 and 76.6 ± 15.6 μM, respectively). Retinal TUNEL staining showed apoptosis in all diseased groups. Percent of apoptotic cells was significantly greater in the elevated IOP+LPS group compared to LPS-treated or elevated IOP groups. Presented data illustrates that both elevated IOP and ocular inflammation augment NOS-2 expression, retinal protein nitration and apoptosis in rats.     

Carbon monoxide reduces neuropathic pain and spinal microglial activation by inhibiting nitric oxide synthesis in mice

Background

Carbon monoxide (CO) synthesized by heme oxygenase 1 (HO-1) exerts antinociceptive effects during inflammation but its role during neuropathic pain remains unknown. Our objective is to investigate the exact contribution of CO derived from HO-1 in the modulation of neuropathic pain and the mechanisms implicated.

Methodology/Principal Findings

We evaluated the antiallodynic and antihyperalgesic effects of CO following sciatic nerve injury in wild type (WT) or inducible nitric oxide synthase knockout (NOS2-KO) mice using two carbon monoxide-releasing molecules (CORM-2 and CORM-3) and an HO-1 inducer (cobalt protoporphyrin IX, CoPP) daily administered from days 10 to 20 after injury. The effects of CORM-2 and CoPP on the expression of HO-1, heme oxygenase 2 (HO-2), neuronal nitric oxide synthase (NOS1) and NOS2 as well as a microglial marker (CD11b/c) were also assessed at day 20 after surgery in WT and NOS2-KO mice. In WT mice, the main neuropathic pain symptoms induced by nerve injury were significantly reduced in a time-dependent manner by treatment with CO-RMs or CoPP. Both CORM-2 and CoPP treatments increased HO-1 expression in WT mice, but only CoPP stimulated HO-1 in NOS2-KO animals. The increased expression of HO-2 induced by nerve injury in WT, but not in NOS2-KO mice, remains unaltered by CORM-2 or CoPP treatments. In contrast, the over-expression of CD11b/c, NOS1 and NOS2 induced by nerve injury in WT, but not in NOS2-KO mice, were significantly decreased by both CORM-2 and CoPP treatments. These data indicate that CO alleviates neuropathic pain through the reduction of spinal microglial activation and NOS1/NOS2 over-expression.

Conclusions/Significance

This study reports that an interaction between the CO and nitric oxide (NO) systems is taking place following sciatic nerve injury and reveals that increasing the exogenous (CO-RMs) or endogenous (CoPP) production of CO may represent a novel strategy for the treatment of neuropathic pain.     

Chronic CO levels have [corrected] a beneficial effect on vascular relaxation in diabetes

Heme oxygenase (HO) has been shown to provide cytoprotection to the vascular system in diabetes. Isolated femoral arteries from diabetic rats treated with cobalt protoporphyrin (CoPP) exhibited increased relaxation to acetylcholine (ACh), which was markedly decreased in control diabetic rats. In control rats treated with either CoPP or with CO releasing molecules-3 (CORM-3), but not in rats treated with biliverdin, we observed an increased dilatory response to ACh. The inhibition of guanylyl-cyclase (GC) with 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) caused a contractile response to ACh in control rats and in biliverdin-treated rats, while in rats treated with CoPP and CORM-3, the ACh dilatory effect was only decreased. Moreover, the inhibition of HO with chromium mesoporphyrin did not change the response to ACh in rats treated with CoPP, suggesting that the improving effect of overproduction of CO on vascular reactivity is due to a decrease in iNOS and the beneficial effect on vascular function.     

Efficacy of thymol against Echinococcus granulosus protoscoleces

The aim of the present work was to determine the in vitro protoscolicidal effect of thymol against Echinococcus granulosus. Protoscoleces of E. granulosus were incubated with thymol at concentrations of 10, 5 and 1 μg/ml. The first signs of thymol-induced damage were observed between 1 and 4 days post-incubation. The maximum protoscolicidal effect was found with thymol at 10 μg/ml, viability reduced to 53.5 ± 11.9% after 12 days of incubation. At day 42, viability was 11.5 ± 15.3% and, reached 0% after 80 days. Thymol at concentrations of 5 and 1 μg/ml provoked a later protoscolicidal effect. Results of viability tests were consistent with the tissue damage observed at the ultrastructural level. The primary site of damage was the tegument of the parasite. The morphological changes included contraction of the soma region, formation of blebs on the tegument, rostellar disorganization, loss of hooks and destruction of microtriches. The data reported in this article demonstrate a clear in vitro effect of thymol against E. granulosus protoscoleces.