Remodeling Of Mesenteric Arteries Research Articles

MWF RAT AS A NOVEL ANIMAL MODEL OF CARDIORENAL SYNDROME TYPE IV

Objective: Cardiorenal syndrome type 4 (CRS type 4) is characterized by primary chronic kidney disease (CKD) leading to cardiac dysfunction and an increase in cardiovascular events. There is an unmet need for suitable animal models of CRS to further define the pathogenesis and progression of CRS to test new therapeutic strategies. We aim to determine if CKD in aged Munich Wistar Frömter (MWF) rat may translate to cardiovascular alterations of CRS. Design and method: Profibrotic markers and angiotensin receptor (ATR) expression was measured by RT-q-PCR in kidney, aorta and heart from 22 and 45-week-old (aged) male MWF rats (n = 7-10/group). Results: Aged MWF showed higher renal expression of tubular damage markers (Kim-1 and Ngal) and profibrotic factors (Col1A1, Col3A1, TGF-beta) together with lower levels of AT2R. Thoracic aorta also exhibited increased expression of profibrotic CTGF-1 and Col1-A1, as well as a lower AT2R expression. Both age groups were hypertensive with similar systolic and diastolic blood pressure levels. However, aged MWF had an increased PWV and heart weight, together with increased intrinsic arterial stiffness and an outward hypertrophic remodeling in mesenteric arteries. In 45-week-old MWF, levels of cardiac CTGF-1, AT1R and AT2R were higher, whereas TGF-beta expression was lower. No differences were observed for Col1A1 or Col3A1. Conclusions: The presence of renal and vascular fibrosis, hypertension, arterial stiffness and cardiac hypertrophy, together with inflammation, vascular remodeling and early profibrotic cardiac environment, potentially counterregulated by AT2R make aged-MWF rat an useful model for CRS study.

LRP1 protects against excessive superior mesenteric artery remodeling by modulating angiotensin II-mediated signaling.

Vascular smooth muscle cells (vSMCs) exert a critical role in sensing and maintaining vascular integrity. These cells abundantly express the low-density lipoprotein receptor-related protein 1 (LRP1), a large endocytic signaling receptor that recognizes numerous ligands, including apolipoprotein E-rich lipoproteins, proteases, and protease-inhibitor complexes. We observed the spontaneous formation of aneurysms in the superior mesenteric artery (SMA) of both male and female mice in which LRP1 was genetically deleted in vSMCs (smLRP1-/- mice). Quantitative proteomics revealed elevated abundance of several proteins in smLRP1-/- mice that are known to be induced by angiotensin II-mediated (AngII-mediated) signaling, suggesting that this pathway was dysregulated. Administration of losartan, an AngII type I receptor antagonist, or an angiotensinogen antisense oligonucleotide to reduce plasma angiotensinogen concentrations restored the normal SMA phenotype in smLRP1-/- mice and prevented aneurysm formation. Additionally, using a vascular injury model, we noted excessive vascular remodeling and neointima formation in smLRP1-/- mice that was restored by losartan administration. Together, these findings reveal that LRP1 regulates vascular integrity and remodeling of the SMA by attenuating excessive AngII-mediated signaling.

Endothelial cyclin I reduces vulnerability to angiotensin II-induced vascular remodeling and abdominal aortic aneurysm risk.

Retinoblastoma protein (Rb) supports vasoprotective E2F Transcription Factor 1 (E2f1)/Dihydrofolate Reductase (Dhfr) pathway activity in endothelial cells. Cyclin I (Ccni) promotes Cyclin-Dependent Kinase-5 (Cdk5)-mediated Rb phosphorylation. Therefore, we hypothesized that endothelial Ccni may regulate cardiovascular homeostasis, vessel remodeling, and abdominal aortic aneurysm (AAA) formation. Aortic CCNI mRNA expression was analyzed in the Gene Expression Omnibus (GEO) GSE57691 cohort consisting of AAA patients (n=39) and healthy controls (n=10). We employed wild-type (WT) mice and endothelial Ccni knockout (Ccnifl/flTie2-Cre) mice to conduct in vivo and ex vivo experimentation using an Angiotensin (Ang) II hypertension model and a CaCl2 AAA model. Mice were assessed for Rb/E2f1/Dhfr signaling, biopterin (i.e., biopterin [B], dihydrobiopterin [BH2], and tetrahydrobiopterin [BH4]) production, cardiovascular homeostasis, vessel remodeling, and AAA formation. Aortic CCNI mRNA expression was downregulated in AAA patients. Both Ang II- and CaCl2-induced WT mice showed aortic Ccni upregulation coupled with vasculoprotective upregulation of Rb/E2f1/Dhfr signaling and biopterins. Endothelial Ccni knockout downregulated medial Rb/E2f1/Dhfr signaling and biopterins in Ang II-induced hypertensive mice, which exacerbated eNos uncoupling and H2O2 production. Endothelial Ccni knockout impaired in vivo hemodynamic responses and endothelium-dependent vasodilatation in ex vivo mesenteric arteries in response to Ang II. Endothelial Ccni knockout exacerbated mesenteric artery remodeling and AAA risk in response to Ang II and CaCl2. Endothelial Ccni acts as a critical negative regulator of eNos uncoupling-mediated ROS generation and thereby reduces vulnerability to hypertension-induced vascular remodeling and AAA development in mice.

Large-Conductance Calcium-Activated Potassium Channel Opener, NS1619, Protects Against Mesenteric Artery Remodeling Induced by Agonistic Autoantibodies Against the Angiotensin II Type 1 Receptor.

BackgroundAgonistic autoantibodies against the angiotensin II type 1 receptor (AT1‐AAs) extensively exist in patients with hypertensive diseases and have been demonstrated to play crucial roles in the pathophysiological process of vascular remodeling. However, the treatment options are limited. The large‐conductance calcium‐activated potassium (BK) channel is a critical regulator and potential therapeutic target of vascular tone and architecture. We have previously observed that AT1‐AAs have an inhibitory effect on BK channels. However, whether BK channel dysfunction is involved in AT1‐AAs‐induced vascular remodeling and the therapeutic effect of BK channel opener is unclear.Methods and ResultsIn our study, mesenteric arteries from AT1‐AAs‐positive rats exhibited increased wall thickness, narrowing of the arteriolar lumen, and increased collagen accumulation. Patch clamp test results showed that the voltage sensitivity of BK channel declined in mesenteric arteriolar smooth muscle cells from AT1‐AAs‐positive rats. Experiments with freshly isolated mesenteric arteriolar smooth muscle cells showed that AT1‐AAs reduced the opening probability, open levels, open dwell time, and calcium sensitivity of BK channel. Experiments with HEK293T cells transfected with GFP‐ZERO‐BK α‐subunit plasmids suggested a BK channel α‐subunit‐dependent mechanism. BK channel α‐subunit deficient, namely KCNMA1 −/− rats showed a phenotype of mesenteric artery remodeling. The administration of NS1619, a specific BK channel opener targeting the α‐subunit, reversed the phenotypic transition and migration induced by AT1‐AAs in cultured mesenteric arteriolar smooth muscle cells. Finally, perfusion of NS1619 significantly relieved the pathological effects induced by AT1‐AAs in vivo.ConclusionsIn summary, we provide compelling evidence that BK channel α‐subunit dysfunction mediates AT1‐AAs‐induced mesenteric artery remodeling. Preservation of BK channel activity may serve as a potential strategy for the treatment of AT1‐AAs‐induced maladaptive resistance artery remodeling.

Fetal Undernutrition Modifies Vascular RAS Balance Enhancing Oxidative Damage and Contributing to Remodeling.

Fetal stress is known to increase susceptibility to cardiometabolic diseases and hypertension in adult age in a process known as fetal programming. This study investigated the relationship between vascular RAS, oxidative damage and remodeling in fetal programming. Six-month old Sprague-Dawley offspring from mothers that were fed ad libitum (CONTROL) or with 50% intake during the second half of gestation (maternal undernutrition, MUN) were used. qPCR or immunohistochemistry were used to obtain the expression of receptors and enzymes. Plasma levels of carbonyls were measured by spectrophotometry. In mesenteric arteries from MUN rats we detected an upregulation of ACE, ACE2, AT1 receptors and NADPH oxidase, and lower expression of AT2, Mas and MrgD receptors compared to CONTROL. Systolic and diastolic blood pressure and plasma levels of carbonyls were higher in MUN than in CONTROL. Vascular morphology evidenced an increased media/lumen ratio and adventitia/lumen ratio, and more connective tissue in MUN compared to CONTROL. In conclusion, fetal undernutrition indices RAS alterations and oxidative damage which may contribute to the remodeling of mesenteric arteries, and increase the risk of adverse cardiovascular events and hypertension.

Comparison of Superior Mesenteric Artery Remodeling and Clinical Outcomes between Conservative or Endovascular Treatment in Spontaneous Isolated Superior Mesenteric Artery Dissection.

The aim of this study was to analyze the superior mesenteric artery (SMA) remodeling after initial conservative or endovascular treatment with a standardized definition and midterm outcomes in patients with spontaneous isolated dissection of the superior mesenteric artery (SIDSMA). This retrospective study enrolled patients with SIDSMA from January 2007 to August 2019. All patients were treated initially with conservative treatment. If they failed the medical treatment, they were converted to interventional treatment. The morphological endpoint was determined by the standardized SMA remodeling, and the clinical endpoints were determined by the in-hospital mortality, hospital stay, and the bowel-related mid-term mortality. A total of 34 consecutive patients with SIDSMA were identified. Twenty-three (67.6%) and eleven (33.4%) patients underwent conservative and interventional treatments, respectively. Clinical features and morphologic changes on CTA were available in 25 (73.5%) patients during the median follow-up of 23.3 months. Standardized SMA remodeling was significantly (p < 0.05) better in patients undergoing endovascular stenting, especially in patients with Yun’s IIb classification. There was no mesenteric ischemia or SMA aneurysm during follow-up period. Patients with SIDSMA can be treated safely with initial conservative treatment. However, significant portions of patients will require endovascular intervention due to the persistent symptoms. Clinically endovascular stenting could be performed successfully, and SMA remodeling was satisfactory during the mid-term follow-up.

Cinnamaldehyde Ameliorates Vascular Dysfunction in Diabetic Mice by Activating Nrf2.

Oxidative stress is known to be associated with the development of diabetes. Cinnamaldehyde (CA) is a spice compound in cinnamon that enhances the antioxidant defense against reactive oxygen species (ROS) by activating nuclear factor erythroid-related factor 2 (Nrf2), which has been shown to have a cardioprotection effect. However, the relationship between CA and Nrf2 in diabetic vascular complications remains unclear. Leptin receptor-deficient (db/db) mice were fed normal chow or diet containing 0.02% CA for 12 weeks. The vascular tone, blood pressure, superoxide level, nitric oxide (NO) production, renal morphology, and function were measured in each group. CA remarkably inhibited ROS generation, preserved NO production, increased phosphorylated endothelial nitric oxide synthase (p-eNOS), attenuated the upregulation of nitrotyrosine, P22 and P47 in aortas of db/db mice, and apparently ameliorated the elevation of type IV collagen, TGF-β1, P22, and P47 in kidney of db/db mice. Feeding with CA improved endothelium-dependent relaxation of aortas and mesenteric arteries, and alleviated the remodeling of mesenteric arteries in db/db mice. Additionally, dietary CA ameliorated glomerular fibrosis and renal dysfunction in diabetic mice. Nrf2 and its targeted genes heme oxygenase-1 (HO-1) and quinone oxidoreductase-1 (NQO-1) were slightly increased in db/db mice and further upregulated by CA. However, these protective effects of CA were reversed in Nrf2 downregulation mice. A prolonged diet of CA protects against diabetic vascular dysfunction by inhibiting oxidative stress through activating of Nrf2 signaling pathway in db/db mice.

Toll-like receptor 7-driven lupus autoimmunity induces hypertension and vascular alterations in mice.

To investigate whether toll-like receptor 7 (TLR7) activation induces an increase in blood pressure and vascular damage in wild-type mice treated with the TLR7 agonist imiquimod (IMQ). Female BALB/c mice (7-9 week old) were randomly assigned to two experimental groups: an untreated control group and a group treated topically with IMQ (IMQ-treated) for 4 or 8 weeks. A group of IMQ-treated mice that take a combination of the antioxidants tempol and apocynin, and another treated IL-17-neutralizing antibody were also performed. TLR7 activation gradually increased blood pressure, associated with elevated plasma levels of anti-dsDNA autoantibodies, splenomegaly, hepatomegaly, and severe expansion of splenic immune cells with an imbalance between proinflammatory T cells and regulatory T cells. TLR7 activation induced a marked vascular remodeling in mesenteric arteries characterized by an increased media--lumen ratio (≈40%), and an impaired endothelium-dependent vasorelaxation in aortas from wild-type mice after 8 weeks of treatment. In addition, an increased ROS production, as a result of the upregulation of NADPH oxidase subunits, and an enhanced vascular inflammation were found in aortas from IMQ-treated mice. These functional and structural vascular alterations induced by IMQ were improved by antioxidant treatment. Anti-IL-17 treatment reduced blood pressure and improved endothelial dysfunction in IMQ-treated mice. Our results demonstrate that TLR7 activation induces the development of hypertension and vascular damage in BALB/c mice, and further underscore the increased vascular inflammation and oxidative stress, mediated in part by IL-17, as key factors contributing to cardiovascular complications in this TLR7-driven lupus autoimmunity model.

Mesenteric Artery Remodeling after Conservative Management in Patients with Isolated Mesenteric Artery Dissection.

To retrospectively investigate factors associated with mesenteric artery remodeling after conservative management of isolated mesenteric artery dissection (IMAD) (dissection of the mesenteric arteries in the absence of aortic dissection or other known causes). A total of 107 patients diagnosed with IMAD between February 2010 and October 2018 were identified. Eighteen patients were excluded because they underwent stent placement (n= 11) or were lost to follow-up (n= 7). A total of 89 patients who underwent conservative management were therefore included in the study. Cox regression analysis was performed to identify factors associated with mesenteric artery remodeling. During 15.9 ± 10.9 months of follow-up, complete remodeling of the mesenteric artery was achieved in 66 patients (74.2%), and partial remodeling was achieved in 23 patients (25.8%). Of the 66 patients with complete remodeling, 6 (9.1%) had type IIa IMAD (visible false lumen, no visible re-entry site), and 60 (90.9%) had type IIb IMAD (thrombosed false lumen). The mean interval between IMAD diagnosis and complete remodeling was 14.4 ± 5.4 months for all patients. The mean intervals for patients with type IIa IMAD were 20.0 ± 6.2 months and 13.9 ± 5.1 months for patients with type IIb IMAD (P= .015). Mesenteric artery remodeling was significantly associated with the presence of symptoms (odds ratio, 10.800; 95% confidence interval, 1.961-59.470; P= .006). Complete remodeling of the mesenteric artery in patients with IMAD treated with conservative management is common, and the presence of symptoms is associated with complete remodeling.

0259 : Neutrophil and thrombospondin-1 implications in flow-mediated remodeling of resistance arteries from mice

On vascular endothelium, shear stress produces vasorelaxation and outward arterial remodeling. A chronic increase in blood flow induces arterial diameter expansion (normalizing shear stress), and is associated with a compensatory hypertrophy to normalize wall strain. This remodeling is due to Inflammation and nitric oxide (NO) production in resistance arteries. A large number of studies have demonstrated that Thrombospondin-1 (TSP1), a homotrimeric glycoprotein, can have an inhibitory action on the NO pathway and a positive effect on inflammation in vitro . Nevertheless, the role of TSP1 on remodeling is poorly understood. We hypothesized that TSP1 is able to participate in this outward arterial remodeling and hypertrophy by immune cells recruitment. We investigated this remodeling in mesenteric resistance arteries of WT or TSP1-KO mice aged to 12-16 weeks were used. An IgG2a isotype control mAb 2A3 or Ly6G-specific mAb 1A8 are used for neutrophil depletion by in vivo administration. Ligation of mesenteric resistance arteries of WT/TSP1- KO and IgG2a/neutrophil-depleted mice allowed modifying blood flow in vivo, thus exposing arteries to low (LF), normal (NF), or high flow (HF). After 7 days, arteries were isolated for in vitro study. Phenylephrine-mediated contraction and Acetylcholine-mediated relaxation were stronger in HF than in NF vessels on WT and IgG2a control mice. Any difference between HF or NF in TSP1-KO and neutrophil-depleted mice were found. Furthermore, passive diameter analysis revealed a higher diameter in HF than NF in WT and IgG2a mice. These differences are lost in TSP1-KO and neutrophil-depleted mice. These results suggest that TSP1 are essential for remodeling in mesenteric arteries by promoting neutrophils recruitment. The author hereby declares no conflict of interest

Ferulic Acid Alleviates Changes in a Rat Model of Metabolic Syndrome Induced by High-Carbohydrate, High-Fat Diet.

Metabolic syndrome is a cluster of metabolic abnormalities characterized by obesity, insulin resistance, hypertension and dyslipidemia. Ferulic acid (FA) is the major phenolic compound found in rice oil and various fruits and vegetables. In this study, we examined the beneficial effects of FA in minimizing insulin resistance, vascular dysfunction and remodeling in a rat model of high-carbohydrate, high-fat diet-induced metabolic changes, which is regarded as an analogue of metabolic syndrome (MS) in man. Male Sprague-Dawley rats were fed a high carbohydrate, high fat (HCHF) diet and 15% fructose in drinking water for 16 weeks, where control rats were fed with standard chow diet and tap water. FA (30 or 60 mg/kg) was orally administered to the HCHF and control rats during the last six weeks of the study. We observed that FA significantly improved insulin sensitivity and lipid profiles, and reduced elevated blood pressure, compared to untreated controls (p < 0.05). Moreover, FA also improved vascular function and prevented vascular remodeling of mesenteric arteries. The effects of FA in HCHF-induced MS may be realized through suppression of oxidative stress by down-regulation of p47phox, increased nitric oxide (NO) bioavailability with up-regulation of endothelial nitric oxide synthase (eNOS) and suppression of tumor necrosis factor-α (TNF-α). Our results suggest that supplementation of FA may have health benefits by minimizing the cardiovascular complications of MS and alleviating its symptoms.

0396 : Prebiotics supplementation improves the endothelial dysfunction induced by a nutritional deficiency in n-3 polyunsaturated fatty acids (PUFA)

Nutritional disorders are associated with a high risk of developing cardiovascular diseases, endothelial dysfunction being an early key marker. We have demonstrated that metabolic alterations induced by a nutritional depletion in n-3 PUFA are improved by a supplementation in prebiotics (non-digestible fructans). The present work focusses on the impact of prebiotics on the endothelial dysfunction induced by the n-3 PUFA depletion in ApoE –/– mice model. C57Bl/6J (WT) and ApoE –/– (KO) mice were fed a n-3 PUFA depleted-diet (DEF) for 12 weeks. For the last fifteen days, mice were or not supplemented with prebiotics (PRE). The vascular morphology and function were evaluated in first, second and third order mesenteric arteries by histology and wire myograph. Micro-arteries from KO DEF PRE mice develop an increased basal tone and present a larger vessel diameter, compared to vessels from non-supplemented mice. The PRE supplementation in KO DEF mice leads to an increased media thickness in first order mesenteric arteries, this is even higher in the second order branch, in comparison to non-supplemented mice. KO DEF PRE micro-arteries contract significantly more in response to a KCl challenge than vessels from non-supplemented mice. As expected micro-arteries from KO DEF mice present an endothelial dysfunction after 12 weeks of n-3 PUFA depletion with a significant decrease of endothelial-dependent relaxation in comparison to WT DEF arteries. The PRE supplementation is able to improve the endothelial function by restoring the endothelial-dependent relaxation in arteries from KO DEF mice. We point out fructan-type prebiotics as a potential therapeutic tool in endothelial dysfunction. Our results argue in favor of an outward muscular remodeling in mesenteric arteries, leading to an increased blood flow and a better vascular reactivity. The results on endothelial function evoke an important implication of the nitric oxide pathway in this phenomenon.

Wistar rats resistant to the hypertensive effects of ouabain exhibit enhanced cardiac vagal activity and elevated plasma levels of calcitonin gene-related peptide.

Ouabain is a cardiac glycoside produced in the adrenal glands and hypothalamus. It affects the function of all cells by binding to Na+/K+-ATPase. Several lines of evidence suggest that endogenous ouabain could be involved in the pathogenesis of essential (particularly, salt-sensitive) hypertension. However, information regarding the postulated hypertensive effect of the long-term administration of low-dose exogenous ouabain is inconsistent. This study was designed to help settle this controversy through the use of telemetric monitoring of arterial blood pressure and to elucidate the ouabain-induced alterations that could either promote or prevent hypertension. Ouabain (63 and 324 µg/kg/day) was administered subcutaneously to male Wistar rats. Radiotelemetry was used to monitor blood pressure, heart rate and measures of cardiovascular variability and baroreflex sensitivity. The continuous administration of ouabain for 3 months did not elevate arterial blood pressure. The low-frequency power of systolic pressure variability, urinary excretion of catecholamines, and cardiovascular response to restraint stress and a high-salt diet as well as the responsiveness to α1-adrenergic stimulation were all unaltered by ouabain administration, suggesting that the activity of the sympathetic nervous system was not increased. However, surrogate indices of cardiac vagal nerve activity based on heart rate variability were elevated. Molecular remodeling in mesenteric arteries that could support the development of hypertension (increased expression of the genes for the Na+/Ca2+ exchanger and Na+/K+-ATPase α2 isoform) was not evident. Instead, the plasma level of vasodilatory calcitonin gene-related peptide (CGRP) significantly rose from 55 (11, SD) in the control group to 89 (20, SD) pg/ml in the ouabain-treated rats (PTukey's = 18.10−5). These data show that long-term administration of exogenous ouabain does not necessarily cause hypertension in rodents. The augmented parasympathetic activity and elevated plasma level of CGRP could be linked to the missing hypertensive effect of ouabain administration.

Abstracts From the 35th Annual Scientific Meeting of the HBPRCA and the 39th Annual Scientific Meeting of the AAS

### EXCESS PRENATAL CORTICOSTERONE EXPOSURE PROGRAMS HYPOTENSION, VASCULAR REMODELLING AND ALTERS THE RESPONSE TO RESTRAINT STRESS IN ADULT MALE MICE O’Sullivan L, Cuffe JSM, Koning A, Singh RR, Moritz KM, Paravicini TM School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia Background: Exposure to excess glucocorticoids in utero is known to program susceptibility to cardiovascular disease in later life. Endogenous levels of glucocorticoids are increased during periods of stressThe long-term cardiovascular implications for the offspring of women who suffer from stress during pregnancy are, however, poorly understood. Aim: To examine the direct effects of prenatal corticosterone (CORT) exposure on cardiovascular and renal outcomes in adult offspring. Methods: Pregnant C57Bl6 mice received CORT (33 g/kg/h) for 60 h from embryonic day 12.5 and allowed to litter naturally. Nephron number was determined in the offspring at postnatal day 30, and radiotelemetry was used to measure blood pressure and heart rate (both basal and during restraint stress) at 12 months. Pressurized myography was used to assess vascular function, structure and mechanics. Results: Excess prenatal CORT reduced nephron endowment by 33% and 20% in male and female offspring (respectively) compared to untreated controls (n=6–7; P <0.05). At 12 months, CORT-exposed male offspring were hypotensive: MAP 104.3 11.0 vs 115.6 5.5 mmHg in untreated controls (n=8–9; P <0.05). These mice also showed a blunted tachycardiac response to restraint stress. Power spectral density analysis of heart rate suggested that this may be due to an altered vagal/sympathetic balance. Prenatal CORT reduced activity levels of female offspring at night, but did not alter any cardiovascular parameters. In male offspring (but not females), prenatal CORT caused inward remodeling of mesenteric arteries (luminal diameter = 202 7 m vs 249 9 m in controls) without affecting vascular reactivity or the elasticity of vascular wall components. Conclusion: Prenatal CORT exposure programs hypotension in male offspring, despite the reduced nephron number and inward vascular remodeling in these animals. In …

Mitochondrial mitophagy in mesenteric artery remodeling in hyperhomocysteinemia

Although high levels of homocysteine also termed as hyperhomocysteinemia (HHcy) has been associated with inflammatory bowel disease and mesenteric artery occlusion, the mitochondrial mechanisms behind endothelial dysfunction that lead to mesenteric artery remodeling are largely unknown. We hypothesize that in HHcy there is increased mitochondrial fission due to altered Mfn‐2/Drp‐1 ratio, which leads to endothelial dysfunction and collagen deposition in the mesenteric artery inducing vascular remodeling. To test this hypothesis, we used four groups of mice: (i) WT (C57BL/6J); (ii) mice with HHcy (CBS+/−); (iii) oxidative stress resistant mice (C3H) and (iv) mice with HHcy and oxidative stress resistance (CBS+/−/C3H). For mitochondrial dynamics, we studied the expression of Mfn‐2 which is a mitochondrial fusion protein and Drp‐1 which is a mitochondrial fission protein by western blots, real‐time PCR and immunohistochemistry. We also examined oxidative stress markers, endothelial cell, and gap junction proteins that play an important role in endothelial dysfunction. Our data showed increase in oxidative stress, mitochondrial fission (Drp‐1), and collagen deposition in CBS+/− compared to WT and C3H mice. We also observed significant down regulation of Mfn‐2 (mitochondrial fusion marker), CD31, eNOS and connexin 40 (gap junction protein) in CBS+/− mice as compared to WT and C3H mice. In conclusion, our data suggested that HHcy increased mitochondrial fission (i.e., decreased Mfn‐2/Drp‐1 ratio, causing mitophagy) that leads to endothelial cell damage and collagen deposition in the mesenteric artery. This is a novel report on the role of mitochondrial dynamics alteration defining mesenteric artery remodeling.

Mesenteric vascular remodeling in different mouse strains

Inflammatory Bowel Disease (IBD) is a category of inflammatory conditions of the colon and small intestine associated with oxidative stress (OS). Hyperhomocysteinemia (HHcy) is known as the cause of mesenteric vascular remodeling, inducing hypertension and acute abdomen pain. Patients with IBD often have HHcy compare to healthy people. We followed alterations of homocysteine (Hcy) level and mesenteric artery remodeling comparing four different strains of mice: C5BJ/L6 wild type (WT) as a control; cystathione beta synthase heterozygote knockout (CBS+/−) with increased level of Hcy; C3H, which is known as the most resistant to (OS) and double‐transgenic CBS/C3H mice. We suggested that Hcy level will be decreased in CBS/C3H compared to CBS, there will be amelioration of hemodynamics in mesenteric artery of CBS/C3H in comparison with CBS mice and attenuation of mesenteric vascular remodeling in CBS/C3H versus CBS. We used blood flow and mesenteric artery reactivity measurements, immunohistochemistry, electron microscopy of mitochondria, measurement of Dpr‐1 level (mediates mitochondrial fission during OS), measurement of Hcy level in plasma, Masson trichrome, PCR and Western blot (eNOS/iNOS, DDAH‐2, SAHH, CBS, CSE, 3MST, MTHFR, DNMT). Our preliminary data suggests that mesenteric vascular remodeling and HHcy are attenuated and hemodynamic of mesenteric artery is ameliorated in CBS/C3H versus CBS mice.

Thrombospondin-1 in Early Flow-Related Remodeling of Mesenteric Arteries from Young Normotensive and Spontaneously Hypertensive Rats

We tested the hypotheses that TSP-1 participates in the initiation of remodeling of small muscular arteries in response to altered blood flow and that the N-terminal domain of TSP-1 (hepI) can reverse the pathological inward remodeling of resistance arteries from SHR.We measured (1) changes in gene/protein expression in MA of 6 week old WKY and SHR exposed to either increased (+ 100 %) or reduced blood flow (- 90 %) for 24-40 hours and (2) structural changes in MA of 12 week old SHR exposed for 3 days to hepI in organ culture.In both HF and LF of WKY, mRNA expression of eNOS, sGCα1 and PKG1β were significantly reduced (p < 0.05), whereas mRNA of TSP1 was markedly increased (p < 0.05). In MA of young SHR, similar results were obtained except that eNOS mRNA was not reduced in LF. Expression of TSP1 protein was significantly increased in LF of young WKY and SHR (p < 0.05). Exposure of MA of 12 week old SHR to hepI (1 µmol/L) resulted in a rapid lumen diameter increase (+ 12 ± 2% after 3 days) without alteration in vascular reactivity, distensibility, media surface area or cell number.These are the first observations of reduced gene expression of eNOS/sGC/PKG and increased expression of TSP1 at the initiation of arterial remodeling in young WKY and SHR, irrespective of its outward or inward outcome. Furthermore, a fragment of TSP-1 rapidly and directly reversed pathological inward arterial remodeling of SHR in vitro.

Mesenteric vascular remodeling in hyperhomocysteinemia

Remodeling by its very nature implies synthesis and degradation of extracellular matrix components (such as elastin, collagen, and connexins). Most of the vascular matrix metalloproteinase (MMP) are latent because of the presence of constitutive nitric oxide (NO). However, during oxidative stress peroxinitrite (ONOO-) activates the latent MMPs and instigates vascular remodeling. Interestingly, in mesenteric artery, homocysteine (Hcy) decreases the NO bio-availability, and folic acid (FA, an Hcy-lowering agent) mitigates the Hcy-mediated mesentery artery dysfunction. Dimethylarginine dimethylaminohydrolase-2 (DDAH-2) and endothelial nitric oxide synthase (eNOS) increases NO production. The hypothesis was that the Hcy decreased NO bio-availability, in part, activating MMP, decreasing elastin, DDAH-2, eNOS and increased vasomotor response by increasing connexin. To test this hypothesis,the authors used 12-week-old C57BJ/L6 wild type (WT) and hyperhomocysteinemic (HHcy)-cystathione beta synthase heterozygote knockout (CBS+/-) mice. Blood pressure measurements were made by radio-telemetry. WT and MMP-9 knockout mice were administered with Hcy (0.67 mg/ml in drinking water). Superior mesenteric artery and mesenteric arcade were analyzed with light and confocal microscopy. The protein expressions were measured by western blot analysis. The mRNA levels for MMP-9 were measured by RT-PCR. The data showed decreased DDAH-2 and eNOS expressions in mesentery in CBS-/+ mice compared with WT mice. Immuno-fluorescence and western blot results suggest increased MMP-9 and connexin-40 expression in mesenteric arcades of CBS-/+ mice compared with WT mice. The wall thickness of third-order mesenteric artery was increased in CBS-/+ mice compared to WT mice. Hcy treatment increased blood pressure in WT mice. Interestingly, in MMP-9 KO, Hcy did not increase blood pressure. These results may suggest that HHcy causes mesenteric artery remodeling and narrowing by activating MMP-9 and decreasing DDAH-2 and eNOS expressions, compromising the blood flow, instigating hypertension, and acute abdomen pain.

Effect of Red Wine on Adipocytokine Expression and Vascular Alterations in Fructose-Fed Rats

Imbalance in adipocytokines secretion is related to the development of metabolic syndrome (MS). In addition, moderate consumption of red wine (RW) decreases the risk of cardiovascular disease. The aim of this study was to evaluate the effects of moderate consumption of RW or ethanol (E) on adiponectin and resistin expression, and vascular alterations in fructose-fed rats (FFRs) as an experimental model of MS. Thirty-day-old male Wistar rats were assigned to control (C), F (10% fructose in drinking water), F+E (4.5 ml/kg), and F+RW (35 ml/kg of Malbec RW containing 4.5 ml/kg E). E and RW were administered during the last 4 weeks of a 10-week period. RW administration to F rats was able to significantly decrease insulin resistance, mesenteric adipose tissue weight, and systolic blood pressure (SBP) compared to F group. F+E only reduced the SBP (P < 0.05 vs. F). F+RW also reduced aortic NAD(P)H-oxidase activity, NAD(P)H subunits Nox4 expression in mesenteric tissue, plasma thiobarbituric acid reactive substances (TBARS), and recovered plasma total antioxidant activity (TAA) compared to F and F+E groups (P < 0.05). Adiponectin expression decreased, whereas resistin, vascular cell adhesion molecules-1 (VCAM-1), and nuclear factor-κB (NF-κB) expression and vascular remodeling in mesenteric arteries were higher in F than in C group (P < 0.05). Only RW was able to partially reverse the aforementioned alterations. In this study, Malbec RW, but not alcohol alone, improved the balance of adipocytokines and attenuated the oxidative stress and vascular inflammation in a model of MS, suggesting that nonalcohol components of RW are responsible for the beneficial effects.

NFATc3 contributes to intermittent hypoxia-induced arterial remodeling in mice

Sleep apnea (SA) is defined as intermittent respiratory arrest during sleep and affects up to 20% of the adult population. SA is also associated with an increased incidence of hypertension and peripheral vascular disease. Exposing rodents to intermittent hypoxia during sleep mimics the cyclical hypoxia/normoxia of SA. We have previously shown that in mice and rats intermittent hypoxia induces ET-1 upregulation and systemic hypertension. Furthermore, intermittent hypoxia (IH) in mice increases nuclear factor of activated T cells isoform 3 (NFATc3) transcriptional activity in aorta and mesenteric arteries, whereas the calcineurin/NFAT inhibitor cyclosporin A prevents IH-induced hypertension. More importantly, NFATc3 knockout (KO) mice do not develop IH-induced hypertension. The goals of this study were to determine the role of NFATc3 in IH-induced arterial remodeling and whether IH-induced NFATc3 activation is mediated by ET-1. Oral administration of both a dual (bosentan) and a selective endothelin receptor type A antagonist (PD155080) during 2 days of IH exposure attenuated NFAT activation in aorta and mesenteric arteries. Rho kinase inhibition with fasudil also prevented IH-induced NFAT activation. Mesenteric artery cross-sectional wall thickness was increased by IH in wild-type (WT) and vehicle-treated mice but not in bosentan-treated and NFATc3 KO mice. The arterial remodeling in mesenteric arteries after IH was characterized by increased expression of the hypertrophic NFATc3 target smooth muscle-alpha-actin in WT but not in KO mice. These results indicate that ET-1 is an upstream activator of NFATc3 during intermittent hypoxia, contributing to the resultant hypertension and increased wall thickness.