Selective Enrichment of Angiomirs in Extracellular Vesicles Released from Ischemic Skeletal Muscles: Potential Role in Angiogenesis and Neovascularization.

MicroRNAs (miRs) regulate physiological and pathological processes, including ischemia-induced angiogenesis and neovascularization. They can be transferred between cells by extracellular vesicles (EVs). However, the specific miRs that are packaged in EVs released from skeletal muscles, and how this process is modulated by ischemia, remain to be determined. We used a mouse model of hindlimb ischemia and next generation sequencing (NGS) to perform a complete profiling of miR expression and determine the effect of ischemia in skeletal muscles, and in EVs of different sizes (microvesicles (MVs) and exosomes) released from these muscles. Ischemia significantly modulated miR expression in whole muscles and EVs, increasing the levels of several miRs that can have pro-angiogenic effects (angiomiRs). We found that specific angiomiRs are selectively enriched in MVs and/or exosomes in response to ischemia. In silico approaches indicate that these miRs modulate pathways that play key roles in angiogenesis and neovascularization, including HIF1/VEGF signaling, regulation of actin cytoskeleton and focal adhesion, NOTCH, PI3K/AKT, RAS/MAPK, JAK/STAT, TGFb/SMAD signaling and the NO/cGMP/PKG pathway. Thus, we show for the first time that angiomiRs are selectively enriched in MVs and exosomes released from ischemic muscles. These angiomiRs could be targeted in order to improve the angiogenic function of EVs for potential novel therapeutic applications in patients with severe ischemic vascular diseases.

Stimulation of soluble guanylate cyclase activity with riociguat promotes angiogenesis and improves neovascularization after limb ischemia.

BACKGROUND AND AIMS: The NO-cGMP pathway is essential for angiogenesis, vasculogenesis and post-natal neovascularization. The key enzyme responsible for the synthesis of cGMP following binding of NO is soluble guanylate cyclase (sGC). Riociguat is the first member of a novel class of compounds known as sGC stimulators. We tested the hypothesis that stimulation of sGC with riociguat might improve neovascularization in response to ischemia. METHODS: In vitro, the angiogenic effect of riociguat was tested in human umbilical vein endothelial cells (HUVECs). In vivo, neovascularization was investigated in a mouse model of limb ischemia. C57Bl/6 mice were treated by gavage with 3 mg/kg/day of riociguat for a total of 28 days. After two weeks of treatment, hindlimb ischemia was surgically induced by femoral artery removal. RESULTS: In a matrigel assay in vitro, riociguat dose-dependently stimulates tubule formation in HUVECs. Cell migration (scratch assay) is also increased in HUVECs treated with riociguat. At the molecular level, riociguat treatment leads to rapid activation of the p44/p42 MAP kinase pathway in HUVECs. Inhibition of protein kinase G (PKG) activity supresses both p44/p42 MAP kinase activation and angiogenesis in HUVECs treated with riociguat. In vivo, treatment with riociguat improves blood flow recovery after ischemia (Laser Doppler imaging), and increases capillary density in ischemic muscles (CD31 immunostaining). Clinically, this is associated with a significant decrease of ambulatory impairment and ischemic damages. Interestingly, mice treated with riociguat also show a 94% increase in the number of bone marrow-derived pro-angiogenic cells (PACs) compared to control mice. Moreover, riociguat treatment is associated with a significant improvement of PAC functions including migratory capacity, adhesion to an endothelial monolayer, and integration into endothelial tubular networks. CONCLUSIONS: The sGC stimulator riociguat promotes angiogenesis and improves neovascularization after ischemia. The mechanism involves PKG-dependent activation of p44/p42 MAP kinase pathway, together with an improvement of PAC number and functions. sGC stimulation could constitute a novel therapeutic strategy to reduce tissue ischemia in patients with severe atherosclerotic diseases.

Preeclampsia is associated with reduced renin, aldosterone, and PlGF levels, and increased sFlt-1/PlGF ratio, and specific angiotensin-converting enzyme Ins-Del gene variants.

We investigated the association of angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism with preeclampsia (PE) in Tunisian women. ACE I/D genotyping was done by PCR in 342 pregnant women with PE and 289 healthy pregnant women. The association between ACE I/D and PE and associated features were also evaluated. Decreased active renin concentration, plasma aldosterone concentration, and placental growth factor (PlGF) were observed in PE cases, while soluble fms-like tyrosine kinase-1 (sFlt-1)/PlGF ratio was significantly higher in the PE group. Distribution of ACE I/D alleles and genotypes were comparable between women with PE and control women. A significant difference in the frequency of the I/I genotype was seen between PE cases and control women according to the recessive model, with a trend towards association in the codominant model. Carriers of the I/I genotype had significantly higher infant birth weights compared to the I/D and the D/D genotype carriers. A dose-dependent relationship was also seen in VEGF and PlGF plasma levels and specific ACE I/D genotypes, with the lowest VEGF levels seen in the I/I genotype carriers compared to the D/D genotype carriers. Similarly, the I/I genotype carriers had the lowest PlGF levels compared to I/D and D/D genotype carriers. Furthermore, when studying the linkage between PE features, we found a positive correlation between PAC and PIGF. Our study suggests a role for ACE I/D polymorphism in the pathogenesis of PE, possibly through modulating VEGF and PlGF levels and infant birth weight, and highlights the relationship between PAC and PlGF.

Contribution of -1031T/C and -376G/A tumor necrosis factor alpha polymorphisms and haplotypes to preeclampsia risk in Tunisia (North Africa).

Preeclampsia is a gestational disorder characterized by hypertension and proteinuria. Excessive release of pro-inflammatory cytokines, particularly tumour necrosis factor-alpha, has been demonstrated to contribute to endothelial activation and poor trophoblast invasion in placental development, resulting in preeclampsia's clinical symptoms. Genetic polymorphisms of tumour necrosis factor-alpha can regulate its production and may play an important role in the pathogenesis of this disease. This study aimed to evaluate the association of five tumour necrosis factor-alpha gene promoter single nucleotide polymorphisms, or their haplotype combinations, with preeclampsia prevalence. This case-control study was conducted on 300 women with preeclampsia and 300 age-matched women with normal pregnancy from Tunisian hospitals. Genotyping of tumour necrosis factor-alpha -1031 T/C, -376 G/A, -308 G/A, -238 G/A, and +489 G/A SNPs was performed on DNA extracted from blood samples using PCR-restriction fragment-length polymorphism analysis. Statistical analysis was performed using the chi-square test. P < 0.01 were considered statistically significant to take into consideration the multiple comparisons. A significantly higher frequency of the minor allele -1031C (p < 0.001) was observed in preeclampsia cases compared to controls. Notably, the -1031C and -376A (CA) haplotype, which correlates with a higher production of TNF-α protein, had a higher incidence in women with preeclampsia (p = 0.0005). Conversely, the TG haplotype had a low frequency in preeclampsia cases compared to controls (p = 0.002) which suggests that it is associated with a reduced incidence of preeclampsia. These results suggest that tumour necrosis factor-alpha polymorphisms, in particular the -1031C/A, and the haplotype CA, contribute to an increased risk of preeclampsia in Tunisian women.

MMP-2 and MMP-9 Polymorphisms and Preeclampsia Risk in Tunisian Arabs: A Case-Control Study.

The abnormal production of matrix metalloproteinases (MMPs), especially MMP-9 and MMP-2, plays a pivotal role in hypertensive disorders of pregnancy, and as such, can influence the development of preeclampsia. These alterations may result from functional genetic polymorphisms in the promoter region of MMP-9 and MMP-2 genes, which modify MMP-9 and MMP-2 expression. We investigated the association of MMP-9 polymorphism rs3918242 (-1562 C>T) and MMP-2 polymorphism rs2285053 (-735 C>T) with the risk of preeclampsia. This case-control study was conducted on 345 women with preeclampsia and 281 age-matched women with normal pregnancies from Tunisian hospitals. Genomic DNA was extracted from whole blood collected at delivery. Genotypes for -1562 C>T and -735 C>T polymorphisms were performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). An increased frequency of heterozygous MMP-9 -1562 C/T genotype carriers was observed in women with preeclampsia compared to healthy controls (p = 0.03). In contrast, the MMP-2 -735 C>T polymorphism was not significantly different regarding frequency distribution of the allele and genotype between healthy pregnant women and women with preeclampsia. Our study suggests that the MMP-9 -1562 C/T variant, associated with high MMP-9 production, could be a genetic risk factor for preeclampsia in Tunisian women.

Increased physical activity is correlated with improved pregnancy outcomes in women with preeclampsia: A retrospective study.

OBJECTIVES: Several studies have focused on the benefits of physical activity to prevent and treat preeclampsia, given that preeclampsia and cardiovascular disease share several risk factors. However, none of these studies have been conducted in Africa. Moreover, it has been demonstrated that exercise training has preventive effects on the development of preeclampsia in mouse models. Therefore, we evaluated the association between the practice of physical activity and the development of this pathology in a Tunisian cohort. STUDY DESIGN: Sixty-one healthy pregnant Tunisian women and 45 women with preeclampsia were recruited and completed the Pregnancy Physical Activity Questionnaire to determine their level and type of physical activity during the entire pregnancy. MAIN OUTCOME MEASURE: Continuous variables were compared using the Mann-Whitney U test, while categorical variables were compared using the Chi-square test. The correlation between preeclampsia features and energy expenditure were assessed using the Pearson's correlation test. RESULTS: Energy expenditure analysis revealed that women with preeclampsia engaged in more sedentary activities than controls, while controls practiced more physical activities. Interestingly, we found a positive correlation between the total amount of energy spent and the duration of pregnancy in controls and women with preeclampsia. CONCLUSIONS: Increasing physical activity is correlated with increasing pregnancy duration which is an index of maternal and fetal health. The practice of physical activities during pregnancy is associated with a healthier pregnancy, while sedentary activities is associated with the development of preeclampsia.

Immune and Apoptosis Mechanisms Regulating Placental Development and Vascularization in Preeclampsia.

Preeclampsia is the most severe type of hypertensive disorder of pregnancy, affecting one in 10 pregnancies worldwide and increasing significantly maternal and neonatal morbidity and mortality. Women developing preeclampsia display an array of symptoms encompassing uncontrolled hypertension and proteinuria, with neurological symptoms including seizures at the end of pregnancy. The main causes of preeclampsia are still unknown. However, abnormal placentation and placenta vascularization seem to be common features in preeclampsia, also leading to fetal growth restriction mainly due to reduced placental blood flow and chronic hypoxia. An over activation of maternal immunity cells against the trophoblasts, the main cells forming the placenta, has been recently shown as an important mechanism triggering trophoblast apoptosis and death. This response will further disrupt the remodeling of maternal uterine arteries, in a first stage, and the formation of new placental vessels in a later stage. A consequent chronic hypoxia stress will further contribute to increase placental stress and exacerbate systemic circulatory changes in the mother. The molecular mechanisms driving these processes of apoptosis and anti-angiogenesis are also not well-understood. In this review, we group main evidences suggesting potential targets and molecules that should be better investigated in preeclampsia. This knowledge will contribute to improve therapies targeting a better placenta formation, having a positive impact on maternal disease prevention and on fetal development.

Impact of obesity on the association of active renin and plasma aldosterone concentrations, and aldosterone-to-renin ratio with preeclampsia.

OBJECTIVE: To evaluate the association of active renin concentration (ARC), plasma aldosterone concentration (PAC) and aldosterone-to-renin ratio (ARR) with the risk of preeclampsia (PE), in particular according to the status of obesity. DESIGN: This retrospective case-control study involved 90 women with PE (mean gestation 35.6 ±â€¯3.6 weeks) and 90 age-matched control women with uncomplicated pregnancies (mean gestation 38.5 ±â€¯2.5 weeks). ARC and PAC were measured by radioimmunoassay; ARR calculated as PAC to ARC ratio. PE cases were stratified into 5 percentiles groups, and analyzed in multivariate logistic regression. RESULTS: Women with PE had significantly lower median ARC and PAC than control women, which were confirmed by percentiles analysis. Spearman correlation demonstrated negative correlation of ARC with body mass index, systolic/diastolic blood pressure. PAC correlated negatively with systolic/diastolic blood pressure, but positively with baby weight, ARC and ARR. On the other hand, ARR positively correlated with BMI and PAC, but negatively with ARC. Lower PAC was associated with PE, irrespective of body weight, while ARC levels were significantly lower in non-obese PE cases vs. control women. ARR was not significantly different between PE cases and control women, when stratified according to obesity. CONCLUSION: Low ARC and PAC in third trimester are more strongly associated with preeclampsia respectively in non-obese and obese women.

Contribution of angiotensinogen M235T and T174M gene variants and haplotypes to preeclampsia and its severity in (North African) Tunisians.

BACKGROUND: Preeclampsia (PE) is a pregnancy-associated hypertensive disorder and a leading cause of maternal and neonatal morbidity and mortality. While its pathogenesis remains ill defined, several candidate genes for PE have been identified, but results remain inconclusive. We investigated the association of the angiotensinogen ( AGT) gene variants M235T and T174M with PE, and we analyzed the contribution of both variants to the severity of PE. METHODS: This case-control study enrolled 550 Tunisian pregnant women: 272 with PE, of whom 147 presented with mild, and 125 with severe PE, along with 278 unrelated age- and ethnically matched control women. AGT genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: Significantly higher M235T minor allele frequency (MAF) was associated with increased risk of PE ( p < 0.001). Decreased frequency of heterozygous T174M genotype carriers were found in control women ( p = 0.015), suggesting a protective effect of this genotype (odds ratio (95% confidence interval) = 0.51 (0.29-0.89)). Two-locus haplotype analysis demonstrated MM and TT haplotypes to be negatively and positively associated with PE, respectively. MAF of M253T, but not T174M, was higher in the severe PE group, and carrying M235T or T174M minor allele was associated with increased body mass index ( p < 0.001) among unselected PE women. CONCLUSIONS: AGT M235T and T174M variants contribute to an increased risk of developing PE, and for M235T to PE severity.

Vascular endothelial growth factor single nucleotide polymorphisms and haplotypes in pre-eclampsia: A case-control study.

An association between vascular endothelial growth factor (VEGFA) gene variants and altered VEGF secretion and preeclampsia (PE) were described, often with inconclusive findings. An ethnic contribution to the association of VEGFA polymorphisms with PE and its associated features was also suggested. To investigate whether common VEGFA single nucleotide polymorphisms (SNP) are linked with PE and associated features in Tunisian women. A case-control study involving 300 women with PE, and 300 age-matched control women. Genotyping of VEGFA rs833052, rs699947, rs833061, rs1570360, rs2010963, rs25648, rs833068, rs833070, rs3025020, and rs3025039SNPs was done by real-time PCR. Minor allele frequency (MAF) of rs833052, rs699947, rs833061, rs1570360, rs2010963, rs25648, rs833068, rs833070, rs3025020, and rs3025039 VEGFA SNP, were not significantly different between PE cases and control women. In addition, there was lack of association of the genotypes of VEGFA SNPs with PE, irrespective of the genetic model used. Seven-locus (rs699947, rs833061, rs1570360, rs2010963, rs25648, rs833068 and rs833070) haplotype analysis demonstrated positive association of ATGCCAA, ACAGCAG and CCAGCGG, and negative association of CCAGCAA and ATGCCGG haplotypes with PE, all of which except for ACAGCAG remained associated with PE after correcting for multiple comparisons. Increased and reduced PE severity was associated with ATGCCAA, and with ATGCCGG and CCAGCAA haplotypes, respectively. Furthermore, carriage of CCGGTAG haplotype was associated with reduced risk of PE. Our study suggests that VEGFA haplotypes, more so than individual SNPs, play a role in PE pathogenesis in Tunisian women. These findings need confirmation in other ethnic populations.

FGF1 and FGF2 mutations in preeclampsia and related features.

BACKGROUND: Fibroblast growth factor (FGF) 1 and FGF2 were previously linked with preeclampsia (PE), possibly through altering decidual and placental FGFR2 expression. Since common variation in FGF1 and FGF2 might influence FGF1 and FGF2 activity, this study evaluated whether common FGF1 and FGF2 variants are linked with PE and associated features. METHODS: The association between FGF1 rs34011 and FGF2 rs2922979 SNPs and PE were tested in 300 women with PE, and 300 age-matched control women. RESULTS: The allelic distribution of FGF1 rs34011 (P < 0.001) but not FGF2 rs2922979, variants were significantly different between PE cases and control women. Marginal association of FGF2 rs2922979 was seen after controlling for key covariates. Setting homozygous major allele genotype (1/1) as reference, significantly higher frequencies of heterozygous rs345011, and reduced frequency of heterozygous rs2922979 genotype carriers were seen in PE cases; the distribution of the remaining genotypes were comparable between cases and controls. Carriage of rs2922979 minor allele correlated with fasting glucose (P = 0.02), while the presence of rs34011 minor allele was not correlated with PE-associated features. CONCLUSIONS: Our study suggests that the genetic variants of FGF1 rs34011, more so than FGF2 rs2922979, may play a role in PE pathogenesis in Tunisian women. These findings need confirmation in other ethnic populations.

Placental growth factor and vascular endothelial growth factor serum levels in Tunisian Arab women with suspected preeclampsia.

The angiogenic factors vascular endothelial growth factor (VEGF) and placental growth factor (PIGF) play a central role in the process of angiogenesis. We evaluated the association of free PIGF and free VEGF levels and the risk of preeclampsia (PE) among Tunisian Arab women, and established the range of VEGF and PIGF in normal healthy pregnancies, between 24 and 42weeks of gestation. This retrospective case-control study included 345 women with PE, and 289 women with uncomplicated pregnancies. PIGF and VEGF plasma levels were quantitated by commercially-available ELISA. Compared to control women, plasma PIGF concentrations were lower in women with PE at all gestation age intervals (P<0.0001), compared to VEGF levels which were significantly lower in women with PE but only during early gestation age intervals ([29-32[ and [32-35[). High odds for developing PE, and correspondingly higher associations, were associated with low PIGF values (less than the 5(th) percentile), at all gestation age intervals. The only exception was recorded for the [29-32 [interval, which was not statistically significant. PIGF testing, recorded at 29-37weeks of gestation, had a higher specificity (93-100%) than sensitivity, and the positive predictive values ranged from 90% to 100% for 24-37weeks of gestation. This indicates that it mainly detects non-PE healthy women as well, and thus may be useful as a screening test, though currently unreliable for diagnostic purposes. Reduced PIGF levels during different gestation age intervals, and reduced VEGF levels during early gestation age intervals are also associated with subsequent development of PE in our population; the gestational age interval adjusted-5(th) percentiles of PIGF provide reference ranges for this marker in normal pregnancy.

Association of common eNOS/NOS3 polymorphisms with preeclampsia in Tunisian Arabs.

We investigated the association of endothelial nitric oxide synthase (NOS3) polymorphisms -786T>C, 27-bp repeat 4b/4a, and Glu298Asp with preeclampsia (PE). This was a case-control study involving 345 unrelated Tunisian women with PE and 289 unrelated age- and ethnically matched control women. The -786C allele was significantly increased in PA patients when compared to healthy controls (P=0.015). In contrast, MAF of Glu298Asp (P=0.103) and 4b/4a (P=0.168) were not significantly different between the study groups. Higher frequencies of heterozygous Glu298/298Asp and homozygous -786T/-786T genotypes were seen in PE cases compared to healthy subjects. The combination of genotypes 221 (-786T>C, Glu298Asp, 4a/4a) was more in PE cases compared with control women (17.68% vs. 8.36%; P=0.029). Multivariate regression analysis confirmed this association. Genetic variation at the NOS3 locus represents a genetic risk factor for increased susceptibility to PE.