The heme oxygenase-1 pathway is involved in calcitonin gene-related peptide-mediated delayed cardioprotection induced by monophosphoryl lipid A in rats

A Potential Involvement of Anandamide in the Modulation of HO/NOS Systems: Women, Menopause, and "Medical Cannabinoids"

Endocannabinoids and their receptors are present in the cardiovascular system; however, their actions under different pathological conditions remain controversial. The aim of our study was to examine the effects of anandamide (AEA) on heme oxygenase (HO) and nitric oxide synthase (NOS) systems in an estrogen-depleted rat model. Sham-operated (SO) and surgically induced estrogen-deficient (OVX) female Wistar rats were used. During a two-week period, a group of OVX rats received 0.1 mg/kg estrogen (E₂) per os, while AEA-induced alterations were analyzed after two weeks of AEA treatment at the dose of 1.0 mg/kg. At the end of the experiment, cardiac activity and expression of HO and NOS enzymes, content of cannabinoid 1 receptor, as well as concentrations of transient potential vanilloid 1 (TRPV1) and calcitonin gene-related peptide (CGRP) were measured. Our results show that estrogen withdrawal caused a significant decrease in both NOS and HO systems, and a similar tendency was observed regarding the TRPV1/CGRP pathway. Two weeks of either AEA or E₂ treatment restored the adverse changes; however, the combined administration of these two molecules did not result in a further improvement. In light of the potential relationship between AEA and HO/NOS systems, AEA-induced upregulation of HO/NOS enzymes may be a therapeutic strategy in estrogen-deficient conditions.

Identification of lncRNA and mRNA expression profiles in rat spinal cords at various time‑points following cardiac ischemia/reperfusion

The identification of the expression patterns of long non-coding RNAs (lncRNAs) and mRNAs in the spinal cord under normal and cardiac ischemia/reperfusion (I/R) conditions is essential for understanding the genetic mechanisms underlying the pathogenesis of cardiac I/R injury. The present study used high-throughput RNA sequencing to investigate differential gene and lncRNA expression patterns in the spinal cords of rats during I/R-induced cardiac injury. Male Sprague Dawley rats were assigned to the following groups: i) Control; ii) 2 h (2 h post-reperfusion); and iii) 0.5 h (0.5 h post-reperfusion). Further mRNA/lncRNA microarray analysis revealed that the expression profiles of lncRNA and mRNA in the spinal cords differed markedly between the control and 2 h groups, and in total 7,980 differentially expressed (>2-fold) lncRNAs (234 upregulated, 7,746 downregulated) and 3,428 mRNAs (767 upregulated, 2,661 downregulated) were identified. Reverse transcription-quantitative polymerase chain reaction analysis was performed to determine the expression patterns of several lncRNAs. The results indicated that the expression levels of lncRNA NONRATT025386 were significantly upregulated in the 2 and 0.5 h groups when compared with those in the control group, whereas the expression levels of NONRATT016113, NONRATT018298 and NONRATT018300 were elevated in the 2 h group compared with those in the control group; however, there was no statistically significant difference between the 0.5 h and control groups. Furthermore, the expression of lncRNA NONRATT002188 was significantly downregulated in the 0.5 and 2 h groups when compared with the control group. The present study determined the expression pattern of lncRNAs and mRNAs in rat spinal cords during cardiac I/R. It was suggested that lncRNAs and mRNAs from spinal cords may be novel therapeutic targets for the treatment of I/R-induced cardiac injury.

Alterations in Gastric Mucosal Expression of Calcitonin Gene-Related Peptides, Vanilloid Receptors, and Heme Oxygenase-1 Mediate Gastroprotective Action of Carbon Monoxide against Ethanol-Induced Gastric Mucosal Lesions

Carbon monoxide (CO) has been reported to contribute to the maintenance of gastric mucosal integrity, gastroprotection, and ulcer healing. However, involvement of transient receptor potential vanilloid receptor type 1 (TRPV1) located on afferent sensory fibers endings and sensory neuropeptide calcitonin gene-related peptide (CGRP) in CO-mediated gastroprotection against ethanol-induced gastric damage has not been explored. Male Wistar rats with and without denervation of afferent sensory neurons induced by capsaicin (total dose 125 mg/kg within 3 days) were pretreated with vehicle, CO donor tricarbonyldichlororuthenium (II) dimer (CORM-2, 5 mg/kg i.g.), administered alone or with CGRP-α (10 μg/kg i.p.) or TRPV1 antagonist capsazepine (5 mg/kg i.g.), followed 30 min later by intragastric (i.g.) administration of 75% ethanol. The area of gastric damage and gastric blood flow (GBF) were assessed planimetrically and by laser flowmetry, respectively. Microscopic evaluation of ethanol-induced gastric lesions was performed after haematoxylin/eosin (H&E) or alcian blue/periodic acid-Schiff/alcian blue (AB/PAS) staining. Gastric mucosal mRNA fold change for heme oxygenase (HMOX)-1, HMOX-2, CGRP-α, CGRP-β, inducible nitric oxide synthase (iNOS), endothelial (e)NOS, neuronal (n)NOS, cyclooxygenase (COX)-1, COX-2, and protein expression for HMOX-1 and TRPV1 was determined by real-time PCR or Western blot, respectively. Pretreatment with CORM-2 combined or not with CGRP reduced ethanol-induced gastric lesions and elevated GBF. Capsaicin-denervation or co-treatment with capsazepine or CGRP and CORM-2 in capsaicin-denervated animals failed to affect these beneficial effects of CO donor. In rats with intact sensory nerves, CORM-2 increased gastric mRNA level for HMOX-1 and CGRP-α. In capsaicin-denervated rats, CORM-2 increased eNOS mRNA fold change and TRPV1 protein expression while capsaicin denervation itself decreased HMOX-1 protein expression and eNOS mRNA level. We conclude that CO prevents gastric mucosa from ethanol-induced lesions due to activation of TRPV1/CGRP-α system and accompanying increase in gastric microcirculation but independently on afferent sensory nerve activity despite the stimulation of TRPV1 protein and CGRP-α mRNA expression.

A Novel α-Calcitonin Gene-Related Peptide Analogue Protects Against End-Organ Damage in Experimental Hypertension, Cardiac Hypertrophy, and Heart Failure

Supplemental Digital Content is available in the text.

Research into the therapeutic potential of α-calcitonin gene–related peptide (α-CGRP) has been limited because of its peptide nature and short half-life. Here, we evaluate whether a novel potent and long-lasting (t_½ ≥7 hours) acylated α-CGRP analogue (αAnalogue) could alleviate and reverse cardiovascular disease in 2 distinct murine models of hypertension and heart failure in vivo.

Effect of olmesartan medoxomil on number and survival of circulating endothelial progenitor cells and calcitonin gene related peptide in hypertensive patients

OBJECTIVE

Injury of vascular endothelium, crucial in vascular disease, is repaired via circulating endothelial progenitor cells (cEPCs). In hypertension, cEPCs number is reduced and function impaired adding further risk for cardiovascular (CV) events. Angiotensin II (Ang II)-induced oxidative stress (OxSt), accelerates cEPCs senescence. Calcitonin gene-related peptide (CGRP), able to prevent and reverse Ang II-induced cEPCs senescence, is reduced in hypertension and stimulated by the antioxidant and anti-inflammatory heme oxygenase (HO)-1. In essential hypertensive patients olmesartan reduced OxSt and markers of CV remodeling and increased HO-1. This study reports in essential hypertensive patients the effect of 6 months treatment with olmesartan on plasma level of CGRP and number and survival of cEPCs.

METHODS AND RESULTS

In 20 essential hypertensive patients treated with olmesartan medoxomil (20  mg per day for 6 months), cEPCs (CD34(+)KDR(+), CD133(+)KDR(+) and CD34(+)CD133(+)KDR(+)) (direct 3-color flow cytometry analysis), apoptosis of cEPCs (CD133(+)KDR(+) cells with Annexin V expression), CGRP determination (ELISA) and HO-1 protein level (western blot) were assessed at baseline and after 3 and 6 months of treatments. Olmesartan normalized blood pressure (P < 0.001), increased cEPCs from baseline (CD34(+)KDR(+): P < 0.003; CD133(+)KDR(+): P < 0.0002; CD34(+)CD133(+)KDR(+): P = 0.0008), reduced cEPCs apoptosis (P < 0.001) and increased CGRP (P < 0.013) and HO-1 (P = 0.039).

CONCLUSION

These results provide a mechanistic rationale for the olmesartan's antioxidant and anti-inflammatory potential translation toward antiatherosclerotic and antiremodeling effects reported on clinical ground.

Calcitonin gene-related peptide, heme oxygenase-1, endothelial progenitor cells and nitric oxide-dependent vasodilation relationships in a human model of angiotensin II type-1 receptor antagonism

OBJECTIVE

An increased number of endothelial progenitor cells (EPCs), which correlated with heme oxygenase-1 gene expression and nitric oxide-mediated vasodilation [flow-mediated dilation (FMD)], has been recently reported by us in Bartter/Gitelman syndromes, rare diseases that represent a human model of endogenous angiotensin (Ang) II type-1 receptor antagonism and depicting an opposite picture of hypertension. Calcitonin gene-related peptide (CGRP), which prevents circulating EPCs senescence and reverses Ang II-induced EPCs senescence is reduced in hypertensive patients, its level is stimulated by heme oxygenase-1 and is related with stimulation of nitric oxide. This study reports on CGRP concentration and heme oxygenase-1 protein level in Bartter/Gitelman syndrome's patients compared with healthy individuals and analyzes their relationships with EPCs [CD34⁺kinase insert domain receptor (KDR⁺), CD133⁺KDR⁺, CD34⁺CD133⁺KDR⁺) as well as FMD.

METHODS AND RESULTS

CGRP concentration (ELISA) and heme oxygenase-1 protein level (sandwich immunoassay) were higher in Bartter/Gitelman syndrome : 38.20 ± 8.23 pg/ml vs. 25.07 ± 3.51, P < 0.002 and 9.44 ± 3.1 ng/ml vs. 5.52 ± 1.1, P < 0.007, respectively. CD133⁺KDR⁺ and CD34⁺CD133⁺KDR⁺ (direct three-color flow cytometry analysis) and FMD (B-mode echo scan of brachial artery) were confirmed higher in Bartter/Gitelman syndrome. CGRP and heme oxygenase-1 strongly correlated (P < 0.0001) and did not differ by group. In Bartter/Gitelman syndrome, both CGRP and heme oxygenase-1 were strongly correlated with both EPCs and FMD.

CONCLUSIONS

Using a human model opposite to hypertension, this study provides information on the relationships between CGRP, heme oxygenase-1, FMD, major clinical and biochemical factors involved in cardiovascular disease, and EPC-specific populations and may also serve to confirm the utility of Bartter/Gitelman syndrome patients in delineating EPCs and related factors roles in the pathophysiology of cardiovascular remodeling in humans.

Endothelial progenitor cells relationships with clinical and biochemical factors in a human model of blunted angiotensin II signaling

Angiotensin II (Ang II) is essential for endothelial progenitor cells (EPCs) function as Ang-II-induced oxidative stress causes senescence of EPCs and endothelial dysfunction and Ang II type 1 receptor blockers increase EPCs. Moreover, EPCs activity is dependent on nitric oxide (NO) and heme oxygenase (HO)-1 as these correlate with EPCs senescence and are reduced in hypertensives. Bartter's/Gitelman's syndrome patients (BS/GS), have increased Ang II yet normo/hypotension along with blunted Ang II signaling, reduced oxidative stress, increased NO and HO-1, thus presenting a unique system to explore EPC biology and its relationship with vascular clinical and biochemical correlates. Circulating EPCs, NO-dependent vasodilation (flow-mediated dilation (FMD)) and HO-1 gene expression were characterized in 10 BS/GS patients and in 10 normotensive subjects. EPCs defined by cell surface antigens CD34+kinase-insert domain receptor (KDR+), CD133+KDR+ and CD133+CD34+KDR+ cells were quantitiated via direct three-color flow-cytometry analysis, HO-1 gene expression by reverse transcription-PCR and FMD by B-mode echo scan of the right brachial artery. Correlation analysis was carried out regarding FMD and EPCs, FMD and HO-1 and EPCs and HO-1. In BS/GS, CD34+KDR+ cell numbers did not differ from controls while CD133+KDR+ and CD133+CD34+KDR+ cell numbers were higher. HO-1 gene expression, as well as FMD, was higher in BS/GS compared with controls. Both CD133+KDR+ and CD133+CD34+KDR+ strongly correlated with both FMD and HO-1. FMD and HO-1 were also strongly correlated. These results document in a human system that EPC numbers and specific populations are related to important clinical and biochemical factors involved in cardiovascular (CV) status and reaffirm the utility of BS/GS patients as a useful system to investigate EPC's role(s) in the pathophysiology of cardiovascular remodeling in humans.

The effect of heme oxygenase inhibition on visual evoked potentials

This study investigated the effect of heme oxygenase (HO) inhibition on visual evoked potentials (VEPs). HO catalyzes the oxidative degradation of heme. Products of HO reaction are biliverdin, ferrous iron, and carbon monoxide (CO). CO is a signal molecule and is an endogenous modulator in the soluble guanylate cyclase/cyclic guanosine monophosphate signaling pathway. Rats were treated with HO inhibitors tin protoporphyrin IX (SnPP IX) or zinc protoporphyrin IX (ZnPP IX) or HO inducer sodium arsenite (Na-arsenite). Soluble guanylate cyclase is inhibited by 1H-[1,2,3]oxydiazolo[4,3-a]quinoxalin-1-one (ODQ) and induced by 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole (YC-1). VEPs were recorded under mild ether anesthesia with the help of stainless steel subdermal electrodes and a photic stimulator. SnPP IX, ODQ or SnPP IX + YC-1 injections significantly prolonged latencies of P3; however, Na-arsenite shortened latency of P3. It has been shown that HO affects VEPs.

The influence of local and systemic preconditioning on oxygenation, metabolism and survival in critically ischaemic skin flaps in pigs

Stress proteins represent a group of highly conserved intracellular proteins that provide adaptation against cellular stress. The present study aims to elucidate the stress protein-mediated effects of local hyperthermia and systemic administration of monophosphoryl lipid A (MPL) on oxygenation, metabolism and survival in bilateral porcine random pattern buttock flaps. Preconditioning was achieved 24h prior to surgery by applying a heating blanket on the operative site (n = 5), by intravenous administration of MPL at a dosage of 35 microg/kg body weight (n = 5) or by combining the two (n = 5). The flaps were monitored with laser Doppler flowmetry, polarographic microprobes and microdialysis until 5h postoperatively. Semiquantitative immunohistochemistry was performed for heat shock protein 70 (HSP70), heat shock protein 32 (also termed haem oxygenase-1, HO-1), and inducible nitrc oxide synthase (iNOS). The administration of MPL increased the impaired microcirculatory blood flow in the proximal part of the flap and partial oxygen tension in the the distal part by approximately 100% each (both P<0.05), whereas both variables remained virtually unaffected by local heat preconditioning. Lactate/pyruvate (L/P) ratio and glycerol concentration (representing cell membrane disintegration) in the distal part of the flap gradually increased to values of approximately 500 mmol/l and approximately 350 micromol/l, respectively (both P<0.01), which was substantially attenuated by heat application (P<0.01 for L/P ratio and P<0.05 for glycerol) and combined preconditioning (P<0.01 for both variables), whereas the effect of MPL was less marked (not significant). Flap survival was increased from 56% (untreated animals) to 65% after MPL (not significant), 71% after heat application (P<0.05) and 78% after both methods of preconditioning (P<0.01). iNOS and HO-1 were upregulated after each method of preconditioning (P<0.05), whereas augmented HSP70 staining was only observed after heat application (P<0.05). We conclude that local hyperthermia is more effective in preventing flap necrosis than systemic MPL administration because of enhancing the cellular tolerance to hypoxic stress, which is possibly mediated by HSP70, whereas some benefit may be obtained with MPL due to iNOS and HO-1-mediated improvement in tissue oxygenation.

Role of eNOS-derived NO in the postischemic anti-inflammatory effects of antecedent ethanol ingestion in murine small intestine

Ingestion of low levels of ethanol 24 h before [ethanol preconditioning (EPC)] ischemia and reperfusion (I/R) prevents postischemic leukocyte rolling (LR) and adhesion (LA), effects that were abolished by adenosine A(2) receptor (ADO-A(2)R) antagonists or nitric oxide (NO) synthase (NOS) inhibitors. The aims of this study were to determine whether NO derived from endothelial NOS (eNOS) during the period of ethanol exposure triggered entrance into this preconditioned state and whether these events were initiated by an ADO-A(2)R-dependent mechanism. Ethanol or distilled water vehicle was administered to C57BL/6J [wild type (WT)] or eNOS-deficient (eNOS-/-) mice by gavage. Twenty-four hours later, the superior mesenteric artery was occluded for 45 min. LR and LA were quantified by intravital microscopy after 30 and 60 min of reperfusion. I/R increased LR and LA in WT mice, effects that were abolished by EPC or NO donor preconditioning (NO-PC). NO-PC was not attenuated by coincident administration of an ADO-A(2)R antagonist. I/R increased LR and LA in eNOS-/- mice to levels comparable with those noted in WT animals. However, EPC only slightly attenuated postischemic LR and LA, whereas NO-PC remained effective as a preconditioning stimulus in eNOS-/- mice. Preconditioning with an ADO-A(2)R agonist (which we previously demonstrated prevents I/R-induced LR and LA in WT animals) failed to attenuate these postischemic adhesive responses in eNOS-/- mice. Our results indicate that EPC is triggered by NO formed secondary to ADO-A(2)R-dependent eNOS activation during the period of ethanol exposure 24 h before I/R.

Role of calcitonin gene-related peptide in the postischemic anti-inflammatory effects of antecedent ethanol ingestion

The aim of this study was to determine the role of calcitonin gene-related peptide (CGRP) in the postischemic anti-inflammatory effects of antecedent ethanol ingestion. Ethanol was administered to wild-type C57BL/6 mice on day 1 as a bolus by gavage at a dose that produces a peak plasma ethanol of 45 mg/dl 30 min after administration. Twenty-four hours later (day 2), the superior mesenteric artery was occluded for 45 min followed by 70 min of reperfusion (I/R). Intravital fluorescence microscopy was used to quantify the numbers of rolling (LR) and adherent (LA) leukocytes labeled with carboxyfluorescein diacetate succinimidyl ester in postcapillary venules of the small intestine. I/R increased LR and LA, effects that were prevented by antecedent ethanol. The postischemic anti-inflammatory effects of ethanol consumption were abolished by administration of a specific CGRP receptor antagonist [CGRP-(8-37)] or after sensory nerve neurotransmitter depletion using capsaicin administered 4 days before ethanol ingestion, which initially induces rapid release of CGRP from sensory nerves, thereby depleting stored neuropeptide. Administration of exogenous CGRP or induction of endogenous CGRP release by treatment with capsaicin 24 h before I/R mimicked the postischemic anti-inflammatory effects of antecedent ethanol ingestion. Preconditioning with capsaicin 24 h before I/R was prevented by coincident treatment with CGRP-(8-37), while exogenous CGRP induced an anti-inflammatory phenotype in mice depleted of CGRP by capsaicin administration 4 days earlier. Our results indicate that the effect of antecedent ethanol ingestion to prevent postischemic LR and LA is initiated by a CGRP-dependent mechanism.

Carbon monoxide induces cytoprotection in rat orthotopic lung transplantation via anti-inflammatory and anti-apoptotic effects

Successful lung transplantation has been limited by the high incidence of acute graft rejection. There is mounting evidence that the stress response gene heme oxygenase-1 (HO-1) and/or its catalytic by-product carbon monoxide (CO) confers cytoprotection against tissue and cellular injury. This led us to hypothesize that CO may protect against lung transplant rejection via its anti-inflammatory and antiapoptotic effects. Orthotopic left lung transplantation was performed in Lewis rat recipients from Brown-Norway rat donors. HO-1 mRNA and protein expression were markedly induced in transplanted rat lungs compared to sham-operated control lungs. Transplanted lungs developed severe intraalveolar hemorrhage, marked infiltration of inflammatory cells, and intravascular coagulation. However, in the presence of CO exposure (500 ppm), the gross anatomy and histology of transplanted lungs showed marked preservation. Furthermore, transplanted lungs displayed increased apoptotic cell death compared with the transplanted lungs of CO-exposed recipients, as assessed by TUNEL and caspase-3 immunostaining. CO exposure inhibited the induction of IL-6 mRNA and protein expression in lung and serum, respectively. Gene array analysis revealed that CO also down-regulated other proinflammatory genes, including MIP-1alpha and MIF, and growth factors such as platelet-derived growth factor, which were up-regulated by transplantation. These data suggest that the anti-inflammatory and antiapoptotic properties of CO confer potent cytoprotection in a rat model of lung transplantation.

Endothelium-dependent vasorelaxation and the expression of calcitonin gene-related peptide in aged rats

To explore the age-related change in endothelium-dependent vasorelaxation, plasma concentrations and the expression of calcitonin gene-related peptide (CGRP) as well as serum concentrations of asymmetry dimethylarginine (ADMA), male Sprague-Dawley rats, aged 6 and 24 months were tested. The level of ADMA and CGRP in blood, and CGRP mRNA in dorsal root ganglia (DRG) were determined by high-performance liquid chromatography (HPLC), radioimmunoassay or semi-quantitative reverse-transcription polymerase chain reaction, respectively. Vasodilator responses to cumulative concentrations of acetylcholine (ACh) (3 x 10(-9) - 3 x 10(-7)M) and CGRP (3 x 10(-10) - 3 x 10(-8)M) were tested at the plateau of contraction in aortas rings. Vasodilator responses to ACh or CGRP at 24 months of age were decreased compared with 6 months. The serum concentration of ADMA at 24 months of age was significantly increased compared with 6 months, while both plasma concentrations of CGRP and the expressions of alpha- and beta-CGRP mRNA were unchanged at two age groups. The results suggest that endothelium-dependent relaxation, but not concentrations and the expressions of CGRP, is decreased in aged rats, and the decrease in endothelium dependence of vasodilator response to CGRP may be related to the elevation of endogenous ADMA.

The cardioprotection of calcitonin gene-related peptide-mediated preconditioning

Preconditioning induced by brief ischemia or hyperthermia or some drugs shows two phases, early and delayed protection. The cardioprotection afforded by preconditioning is related to stimulation of endogenous mediators release. Calcitonin gene-related peptide (CGRP), a major transmitter of capsaicin-sensitive sensory nerves, has recently been shown to play an important role in mediation of the preconditioning induced by brief ischemia or hyperthermia or by some drugs, and alpha-CGRP seems to play a major role in the mediation of delayed preconditioning. It has been shown that the cardioprotection afforded by CGRP-mediated preconditioning is due to inhibition of cardiac tumor necrosis factor-alpha (TNF-alpha) production, but not to the activation of the K(ATP) channel.