Local delivery of human tissue kallikrein gene accelerates spontaneous angiogenesis in mouse model of hindlimb ischemia

Local induction of angiotensin-converting enzyme in the kidney as a mechanism of progressive renal diseases

Angiotensin Converting Enzyme (ACE) or Kininase II has a pivotal role determining the local activity of the renin angiotensin and kallikrein kinin systems. Angiotensin II (Ang II), a main hormone of the renin system, has a well established participation as a renal injury agent in models of renal disease with tubulointerstitial fibrosis. Although, since its discovery, ACE has been known to convert Ang I to Ang II, and to inactivate bradykinin (BK), only recently has been emerged evidence for a role of BK with renal protective and antifibrotic effects opposing Ang II. Pertinent to the tubulointerstitial injury, where infiltration and proliferation of macrophages and fibroblast occur, ACE also regulates the levels of the natural hemoregulatory peptide, N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP). Owing the importance of tissue ACE, its distribution was studied in several models of renal injury. The results showed increased ACE in proximal tubules and ACE induction in the cell infiltrated tubulointerstitium (macrophages and myofibroblasts) of injured kidneys from hypokalemic, Goldblatt hypertensive, Ang II and phenylefrine infused rats, and in both human diabetic and membranous nephropathies. ACE, in addition to Ang II generation, may play a pathogenic role through the hydrolysis of BK and Ac-SDKP. Thus, local increase in ACE can be a novel mechanism involved in tubulointerstitial renal injury, providing, from an anatomical ground, a pathological basis for the putative deleterious effect of ACE in the diseased kidneys, and the beneficial effect of ACE inhibition.

Paracrine control of vascularization and neurogenesis by neurotrophins

The neuronal system plays a fundamental role in the maturation of primitive embryonic vascular network by providing a paracrine template for blood vessel branching and arterial differentiation. Furthermore, postnatal vascular and neural regeneration cooperate in the healing of damaged tissue. Neurogenesis continues in adulthood although confined to specific brain regions. Following ischaemic insult, neural staminal cells contribute towards the healing process through the stimulation of neurogenesis and vasculogenesis. Evidence indicates that nerves and blood vessels exert a reciprocal control of their own growth by paracrine mechanisms. For instance, guidance factors, including vascular endothelial growth factor A (VEGF-A) and semaphorins, which share the ability of binding neuropilin receptors, play a pivotal role in the tridimensional growth pattern of arterial vessels and nerves. Animal models and clinical studies have demonstrated a role of VEGF-A in the pathogenesis of ischaemic and diabetic neuropathies. Further, supplementation with VEGF-A ameliorates neuronal recovery by exerting protective effects on nerves and stimulating reparative neovascularization. Human tissue kallikrein, a recently discovered angiogenic and arteriogenic factor, accelerates neuronal recovery by stimulating the growth of vasa nervorum. Conversely, the neurotrophin nerve growth factor, known to regulate neuronal survival and differentiation, is now regarded as a stimulator of angiogenesis and arteriogenesis. These results indicate that angiogenesis and neurogenesis are paracrinally regulated by growth factors released by endothelial cells and neurons. Supplementation of these growth factors, alone or in combination, could benefit the treatment of ischaemic diseases and neuropathies.

The kallikrein-kinin and the renin-angiotensin systems have a multilayered interaction

Understanding the physiological role of the plasma kallikrein-kinin system (KKS) has been hampered by not knowing how the proteins of this proteolytic system, when assembled in the intravascular compartment, become activated under physiological conditions. Recent studies indicate that the enzyme prolylcarboxypeptidase, an ANG II inactivating enzyme, is a prekallikrein activator. The ability of prolylcarboxypeptidase to act in the KKS and the renin-angiotensin system (RAS) indicates a novel interaction between these two systems. This interaction, along with the roles of angiotensin converting enzyme, cross talk between bradykinin and angiotensin-(1-7) action, and the opposite effects of activation of the ANG II receptors 1 and 2 support a hypothesis that the plasma KKS counterbalances the RAS. This review examines the interaction and cross talk between these two protein systems. This analysis suggests that there is a multilayered interaction between these two systems that are important for a wide array of physiological functions.

Inhibition of hypoxia-induced angiogenesis by cigarette smoke exposure: impairment of the HIF-1alpha/VEGF pathway

Smoking is a major risk factor for atherosclerotic diseases. However, the impact of cigarette smoke exposure on neovascularization that develops in response to tissue ischemia is unknown. Here we demonstrate that cigarette smoke extracts inhibit hypoxia-induced in vitro angiogenesis (matrigel assay) in human umbilical vascular endothelial cells. In vivo, mice exposed to cigarette smoke (MES) were shown to have a significant impairment of angiogenesis following surgically induced hindlimb ischemia. The reduced angiogenic response in MES was documented by Laser Doppler flow perfusion studies and capillary density analyses in ischemic hindlimbs. Inhibition of angiogenesis by cigarette smoke in vitro and in vivo was associated with a reduced expression of hypoxia-inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) in hypoxic conditions. Administration of an adenoviral vector encoding for HIF-1alpha/VP16, a hybrid transcription factor that is stable in hypoxic and normoxic conditions, restored VEGF expression and completely reversed the cigarette smoke inhibition of angiogenesis in hypoxic conditions. Taken together, these results suggest that cigarette smoke exposure impairs angiogenesis by inhibiting VEGF through decreased expression of HIF-1alpha in hypoxic conditions.

Angiotensin-converting enzyme inhibitor promotes coronary collateral circulation in patients with coronary artery disease

Previous studies have suggested that angiotensin-converting enzyme inhibitors (ACEI) promote collateral circulation in ischemic limbs of rabbits. The present study was designed to determine the association between treatment with ACEI and the development of coronary collateral circulation, as assessed by the Rentrop Score, in patients with coronary artery disease (CAD) in a case - control study. Subjects included 456 patients with angina who underwent coronary angiography. Those who had one (1-V), two (2-V) or three (3-V) significantly stenosed vessels, and who received only ACEI without any other anti-hypertensive medication were defined as cases (n=33), and age, sex and body mass index-matched subjects (n=56) were selected as controls. Among 1-V patients, but not 2-V or 3-V patients, the cases included a higher percentage of patients with Rentrop Score of at least 1 than the controls, suggesting that ACEI was associated with coronary collateral circulation. Patients with 1-V disease who were treated with ACEI were most likely [odds ratio (confidence interval): 6.1 (1.4-30.1)] to develop collateral circulation, as assessed by a multiple logistic regression analysis. Therefore, treatment with ACEI was associated with the development of collateral circulation in patients with CAD, suggesting that such an action is associated with bradykinin production by ACEI.

Structural elements of kallistatin required for inhibition of angiogenesis

Kallistatin is a serpin first identified as a specific inhibitor of tissue kallikrein. Our recent studies showed that kallikrein promoted angiogenesis, whereas kallistatin inhibited angiogenesis and tumor growth. This study is aimed to identify the structural elements of kallistatin essential for its antiangiogenic function. Kallistatin mutants at the hinge region (A377T) and a major heparin-binding domain (K312A/K313A) were created by site-directed mutagenesis. Recombinant kallistatin mutant A377T did not bind or inhibit tissue kallikrein activity. Wild-type kallistatin and kallistatin mutant A377T, but not kallistatin mutant K312A/K313A lacking heparin-binding activity, inhibited VEGF-induced proliferation, growth, and migration of human microvascular endothelial cells. Similarly, wild-type kallistatin and kallistatin mutant A337T, but not kallistatin mutant K312A/K313A, significantly inhibited VEGF-induced capillary tube formation of cultured endothelial cells in Matrigel and capillary formation in Matrigel implants in mice. To elucidate the role of the heparin-binding domain in modulating angiogenesis, we showed that wild-type kallistatin interrupted the binding of (125)I-labeled VEGF to endothelial cells, whereas kallistatin mutant K312A/K313A did not interfere with VEGF binding. Consequently, wild-type kallistatin, but not kallistatin mutant K312A/K313A, suppressed VEGF-induced phosphorylation of Akt. Taken together, these results indicate that the heparin-binding domain, but not the reactive site loop of kallistatin, is essential for inhibiting VEGF-induced angiogenesis.

Branching out: a molecular fingerprint of endothelial differentiation into tube-like structures generated by Affymetrix oligonucleotide arrays

The process of endothelial differentiation into a network of tube-like structures with patent lumens requires an integrated program of gene expression. To identify genes upregulated in endothelial cells during the process of tube formation, RNA was prepared from several different time points (0, 4, 8, 24, 40, and 48 hours) and from three different experimental models of human endothelial tube formation: in collagen gels and fibrin gels driven by the combination of PMA (80), bFGF (40 ng/ml) and bFGF (40 ng/ml) or in collagen gels driven by the combination of HGF (40 ng/ml) and VEGF (40 ng/ml). Gene expression was evaluated using Affymetrix Gene Chip oligonucleotide arrays. Over 1000 common genes were upregulated greater than twofold over baseline at one or more time points in the three different models. In the present study, we discuss the identified genes that could be assigned to major functional classes: apoptosis, cytoskeleton, proteases, matrix, and matrix turnover, pumps and transporters, membrane lipid turnover, and junctional molecules or adhesion proteins.

Expression of kinin B(1) receptor in fresh or cultured rabbit aortic smooth muscle: role of NF-kappa B

Kinin B(1) receptor (B(1)R) expression and the importance of the transcription factor nuclear factor (NF)-kappa B in this process were evaluated in models based on the rabbit aorta: freshly isolated tissue (postisolation induction) and cultured smooth muscle cells (SMCs). A 3-h incubation of freshly isolated tissues determined a sharp B(1)R mRNA increase (RT-PCR). Coincubation of tissues with a stimulus (interleukin-1 beta, fetal bovine serum, epidermal growth factor, or cycloheximide) further increased mRNA levels. Cultured SMCs possessed a basal population of surface B(1)Rs ([(3)H]Lys-des-Arg(9)-bradykinin binding) that was upregulated by treatments with the same set of stimuli (binding, mRNA, nuclear runon). Pharmacological inhibitors of NF-kappa B (MG-132, BAY 11-7082, dexamethasone) or actinomycin D reduced the postisolation induction of B(1)Rs in fresh aortic tissue (contractility or mRNA) and the cytokine effect on cells (mRNA, binding). NF-kappa B may be a common mediator of various stimuli that increase B(1)R gene transcription in the rabbit aorta, including tissue isolation, but cycloheximide also stabilizes B(1)R mRNA. The SMC models faithfully mimic the in vivo situation with regard to B(1)R regulation.

Ramipril improves hemodynamic recovery but not microvascular response to ischemia in spontaneously hypertensive rats

BACKGROUND

Angiotensin converting enzyme (ACE) inhibition exerts positive effects on the microvasculature of normotensive animals, although this concept is not universally accepted. Recently, ACE inhibitors have been suggested to be useful for rescue in peripheral ischemia.

METHODS

We investigated whether chronic treatment with the ACE inhibitor ramipril may have a positive impact on the defective healing response to ischemia that is typical of spontaneously hypertensive rats (SHR). Unilateral limb ischemia was induced in 20-week-old SHR by surgically removing the left femoral artery. Rats were allowed to regain consciousness and then were randomly allocated to treatment with ramipril (1 mg/kg body weight in drinking water) or vehicle for 28 days.

RESULTS

The SHR failed to develop reparative angiogenesis in response to ischemia, thus having inadequate perfusion recovery. Ramipril reduced both tail-cuff systolic blood pressure (180 +/- 7 v 207 +/- 2 mm Hg in the vehicle group at 28 days, P < .05) and intra-arterial mean blood pressure (115 +/- 6 v 135 +/- 5 mm Hg in the vehicle group, P < .05). These effects were associated with increased responsiveness to endothelium-dependent vasodilatation by acetylcholine. Treatment with ramipril did not influence muscular capillary and arteriole density but accelerated the rate of perfusion recovery, leading to complete healing within 28 days after surgery.

CONCLUSIONS

These results indicate that ACE inhibition by ramipril may be useful for the treatment of peripheral vascular complications in hypertension.

Evidence for the importance of angiotensin II type 1 receptor in ischemia-induced angiogenesis

The role of the renin-angiotensin system (RAS) in angiogenesis is little known. Here, we show that the angiotensin II (ATII) type 1 (AT1) receptor plays an important role in ischemia-induced angiogenesis. Well-developed collateral vessels and angiogenesis were observed in wild-type (WT) mice in response to hindlimb ischemia, whereas these responses were reduced in ATII type 1a receptor knockout (AT1a(-/-)) mice. Ischemia-induced angiogenesis was also impaired in WT mice treated with the AT1 receptor blocker TCV-116. These effects were not due to reduced systemic blood pressure (SBP), because hydralazine treatment preserved angiogenesis in WT mice although it reduced SBP to a level similar to that of AT1a(-/-) mice. Infiltration of inflammatory mononuclear cells (MNCs), including macrophages and T lymphocytes, was suppressed in the ischemic tissues of AT1a(-/-) mice compared with WT mice. Double immunofluorescence staining revealed that infiltrated macrophages and T lymphocytes expressed VEGF, and the expression of VEGF and monocyte chemoattractant protein-1 was also decreased in AT1a(-/-). Finally, the impaired angiogenesis in AT1a(-/-) mice was rescued by intramuscular transplantation of MNCs obtained from WT mice, further indicating the importance of MNC infiltration in ischemia-induced angiogenesis. Thus, the ATII--AT1 receptor pathway promotes early angiogenesis by supporting inflammatory cell infiltration and angiogenic cytokine expression.

Molecular structure and alternative splicing of the human carboxypeptidase M gene

Using RACE technology the 5' and 3' ends of human carboxypeptidase M (CPM) mRNA were determined and found to be divergent from the published sequence. With these results the complete structure of the human CPM gene was established based on the human genome sequence in the GenBank database. The gene was shown to contain 9 exons comprising at least 75 kb of genomic sequence. A novel first exon of 30 bp was identified and an upstream promoter sequence containing several transcription factor binding sites was found by computer analysis. Furthermore, the ATG starting codon was detected defining an open reading frame of 1329 bp that codes for a protein of 443 residues. Additionally, the polyadenylation site was discovered, determining a 3' noncoding region of 2000 nucleotides. The exon-intron boundaries diverged substantially compared to those of the other basic carboxypeptidases, CPD, CPE, CPN, and AEBP1. Cloning and sequencing of RT-PCR products from different tissues revealed alternative splicing of exons 3 and 5, which results in the generation of four different mRNA isoforms. RNA extracted from tumor tissues contained more CPM mRNA than control tissue, suggesting an upregulation of CPM expression in tumors and raising the question of the role of this enzyme in cancer.

Angiotensin AT(1) receptor signalling modulates reparative angiogenesis induced by limb ischaemia

1. The concept that angiotensin II exerts pro-angiogenic activity is not universally accepted. We evaluated whether inhibition of the renin-angiotensin system (RAS) would influence reparative angiogenesis in a murine model of limb ischaemia. 2. Perfusion recovery following surgical removal of the left femoral artery was analysed by laser Doppler flowmetry in mice given the ACE inhibitor ramipril (1 mg kg(-1) per day), the AT(1) antagonist losartan (15 mg kg(-1) per day), or vehicle. Muscular capillarity was examined at necroscopy. Ramipril-induced effects were also studied under combined blockade of kinin B(1) and B(2) receptors. Furthermore, the effects of ischaemia on AT(1) gene expression and ACE activity were determined. 3. In untreated mice, muscular AT(1a) gene expression was transiently decreased early after induction of limb ischaemia, whereas AT(1b) mRNA was up-regulated. ACE activity was reduced in ischaemic muscles at 1 and 3 days. Gene expression of AT(1) isoforms as well as ACE activity returned to basal values by day 14. Spontaneous neovascularization allowed for complete perfusion recovery of the ischaemic limb after 21 days. 4. Reparative angiogenesis was negatively influenced by either ramipril (P<0.02) or losartan (P<0.01), leading to delayed and impaired post-ischaemic recovery (50 - 70% less compared with controls). Ramipril-induced effects remained unaltered under kinin receptor blockade. 5. The present study indicates that (a) expression of angiotensin II AT(1) receptors and ACE activity are modulated by ischaemia, (b) ACE-inhibition or AT(1) antagonism impairs reparative angiogenesis, and (c) intact AT(1) receptor signalling is essential for post-ischaemic recovery. These results provide new insights into the role of the RAS in vascular biology and suggest cautionary use of ACE inhibitors and AT(1) antagonists in patients at risk for developing peripheral ischaemia.

A synthetic tissue kallikrein inhibitor suppresses cancer cell invasiveness

Serine proteinases modulate the interaction of tumor cells with extracellular matrix components during extravasation and metastasis. The serine proteinase tissue kallikrein has been previously demonstrated in several human adenocarcinomas, and we presently report the localization of immunoreactive kallikrein and its mRNA in pancreatic adenocarcinoma. In addition, a synthetic peptide-based inhibitor specific for tissue kallikrein (FE999024) was used in our studies to explore a possible role for kallikrein in cancer cell invasiveness. Matrigel invasion assays were performed with a human breast-cancer cell line, MDA-MB-231, which expresses tissue kallikrein in culture. In the presence of FE999024 invasion through Matrigel was inhibited in a dose-dependent manner to a maximum of 39%. We also developed a novel ex vivo assay in which breast cancer cells are infused into the pulmonary circulation of artificially ventilated explanted rat lungs. At intervals up to 6 hours after infusion pulmonary invasion was quantified by bronchial alveolar lavage to recover human cancer cells from the airspace. Invading cells in the lung interstitium were also quantified after immunohistochemistry with a monoclonal antibody specific for human cytokeratin 18. The synthetic kallikrein inhibitor attenuates breast cancer cell invasion into the airspace by 33% when quantified by lavage recovery and up to 34% as quantified in the lung interstitium by cytokeratin 18 immunostaining. Our results indicate tissue kallikrein may participate in the invasion and metastasis of human adenocarcinomas. The newly developed explanted rodent lung assay should be useful for the study of cancer cells, neutrophils, or other extravasating cells.

Targeting kinin receptors for the treatment of tissue ischaemia

Kinins, the biological end-products of the kallikrein-kininogen system, influence many aspects of the cellular function. Interest in this peptidergic system has been renewed recently by the discovery that kinins exert cardiovascular protective effects and promote post-ischaemic recovery by stimulating vascular growth. Pharmacological and genetic studies indicate that induction of kallikrein and kinin receptors by ischaemia is functionally relevant in the natural host response that permits perfusion recovery and tissue healing. Furthermore, potentiation of the generation of kinins by continuous supply of tissue kallikrein promotes reparative angiogenesis through stimulation of the release of nitric oxide and prostaglandins. Strategies that activate kinin receptors might be applicable to the treatment of occlusive vascular disease, whereas kinin receptor antagonists could represent therapeutic reagents against pathological angiogenesis in cancer and chronic inflammatory conditions.

The hemostatic system and angiogenesis in malignancy

Coagulopathy and angiogenesis are among the most consistent host responses associated with cancer. These two respective processes, hitherto viewed as distinct, may in fact be functionally inseparable as blood coagulation and fibrinolysis, in their own right, influence tumor angiogenesis and thereby contribute to malignant growth. In addition, tumor angiogenesis appears to be controlled through both standard and non-standard functions of such elements of the hemostatic system as tissue factor, thrombin, fibrin, plasminogen activators, plasminogen, and platelets. "Cryptic" domains can be released from hemostatic proteins through proteolytic cleavage, and act systemically as angiogenesis inhibitors (e.g., angiostatin, antiangiogenic antithrombin III aaATIII). Various components of the hemostatic system either promote or inhibit angiogenesis and likely act by changing the net angiogenic balance. However, their complex influences are far from being fully understood. Targeted pharmacological and/or genetic inhibition of pro-angiogenic activities of the hemostatic system and exploitation of endogenous angiogenesis inhibitors of the angiostatin and aaATIII variety are under study as prospective anti-cancer treatments.

Angiogenesis gene therapy to rescue ischaemic tissues: achievements and future directions

Ischaemic diseases are characterized by an impaired supply of blood resulting from narrowed or blocked arteries that starve tissues of needed nutrients and oxygen. Coronary-atherosclerosis induced myocardial infarction is one of the leading causes of mortality in developed countries. Ischaemic disease also affects the lower extremities. Considerable advances in both surgical bypassing and percutaneous revascularization techniques have been reached. However, many patients cannot benefit from these therapies because of the extension of arterial occlusion and/or microcirculation impairment. Consequently, the need for alternative therapeutic strategies is compelling. An innovative approach consists of stimulating collateral vessel growth, a natural host defence response that intervenes upon occurrence of critical reduction in tissue perfusion (Isner & Asahara, 1999). This review will debate the relevance of therapeutic angiogenesis for promotion of tissue repair. The following issues will receive attention: (a) vascular growth patterns, (b) delivery systems for angiogenesis gene transfer, (c) achievements of therapeutic angiogenesis in myocardial and peripheral ischaemia, and (d) future directions to improve effectiveness and safety of vascular gene therapy.

Gene therapy for therapeutic angiogenesis in critically ischaemic lower limb - on the way to the clinic

Currently, no effective pharmacological treatment is available for vascularisation defects in lower limbs. Many patients presenting with persistent pain and ischaemic ulcers are not suitable candidates for surgical or endovascular approaches. Further refinement of the available methods will undoubtedly lead to a more active approach towards treatment of peripheral arterial occlusive disease (PAOD). Recently, therapeutic angiogenesis, in the form of recombinant growth factor administration or gene therapy, has emerged as a novel tool to treat these patients. However, improved gene transfer methods and better understanding of blood vessel formation are required to bring therapeutic angiogenesis to clinical practice. Here we review the clinical problem (PAOD), mechanisms of blood vessel formation (angiogenesis, vasculogenesis and arteriogenesis), experimental evidence and clinical trials for therapeutic angiogenesis in critically ischaemic lower limbs. Also, angiogenic growth factors, including vascular endothelial growth factors (VEGFs) and fibroblast growth factors (FGFs), delivery methods, and vectors for gene transfer in skeletal muscle, are discussed. In addition to vascular growth, gene transfer of growth factors may enhance regeneration, survival, and innervation of ischaemic skeletal muscle. Nitric oxide (NO) appears to be a key mediator in vascular homeostasis and growth, and a reduction in its production by age, hypercholesterolemia or diabetes leads to the impairment of ischaemic disorders.

Absence of ligand-induced regulation of kinin receptor expression in the rabbit

The induction of B(1) receptors (B(1)Rs) and desensitization or down-regulation of B(2) receptors (B(2)Rs) as a consequence of the production of endogenous kinins has been termed the autoregulation hypothesis. The latter was investigated using two models based on the rabbit: kinin stimulation of cultured vascular smooth muscle cells (SMCs) and in vivo contact system activation (dextran sulphate intravenous injection, 2 mg kg(-1), 5 h). Rabbit aortic SMCs express a baseline population of B(1)Rs that was up-regulated upon interleukin-1beta treatment ([(3)H]-Lys-des-Arg(9)-BK binding or mRNA concentration evaluated by RT - PCR; 4 or 3 h, respectively). Treatment with B(1)R or B(2)R agonists failed to alter B(1)R expression under the same conditions. Despite consuming endogenous kininogen (assessed using the kinetics of immunoreactive kinin formation in the plasma exposed to glass beads ex vivo) and producing hypotension mediated by B(2)Rs in anaesthetized rabbits, dextran sulphate treatment failed to induce B(1)Rs in conscious animals (RT - PCR in several organs, aortic contractility). By contrast, lipopolysaccharide (LPS, 50 microg kg(-1), 5 h) was an effective B(1)R inducer (kidney, duodenum, aorta) but did not reduce kininogen reserve. We tested the alternate hypothesis that endogenous kinin participate in LPS induction of B(1)Rs. Kinin receptor antagonists (icatibant combined to B-9858, 50 microg kg(-1) of each) failed to prevent or reduce the effect of LPS on B(1)R expression. Dextran sulphate or LPS treatments did not persistently down-regulate vascular B(2)Rs (jugular vein contractility assessed ex vivo). The kinin receptor autoregulation hypothesis is not applicable to primary cell cultures derived from a tissue known to express B(1)Rs in a regulated manner (aorta). The activation of the endogenous kallikrein-kinin system is ineffective to induce B(1)Rs in vivo in an experimental time frame sufficient for B(1)R induction by LPS.

Role of calcitonin gene-related peptide and kinins in post-ischemic intestinal reperfusion

The involvement of kinins, calcitonin gene-related peptide (CGRP), and tachykinins during mesenteric post-ischemic reperfusion was studied in anesthetized rats by using antagonists for bradykinin (BK) B1, BK B2, CGRP1, or tachykinin NK1 receptor, or by capsaicin-induced desensitization. B1, B2, or CGRP1 receptor antagonists or desensitization attenuated the transient hypotension and plasma protein and leukocyte infiltration of intestinal wall observed during post-ischemic reperfusion. These effects were abolished by the combination of B2 and CGRP1 blockade as well as by B2 antagonism in capsaicinized rats, while NK1 blockade was ineffective. Our results suggest that kinins and CGRP contribute to systemic vasodilatation and microvascular leakage during mesenteric reperfusion. Pharmacological blockade of these systems could help preventing hypotension and intestinal injury consequent to reperfusion.