Reshef Tal

The Role of Hypoxia and Hypoxia-Inducible Factor-1Alpha in Preeclampsia Pathogenesis

ABSTRACT Preeclampsia affects 5%–8% of pregnancies and is the leading worldwide cause of maternal and fetal morbidity and mortality. Preeclampsia is associated with shallow trophoblast invasion and inadequate spiral artery remodeling, which are widely believed to lead to placental hypoxia, the putative culprit initiating the cascade of events that ultimately results in the maternal manifestations of the disease. Despite extensive research, however, the pathophysiology of this disease remains poorly understood, no effective prevention exists, and treatment is limited to symptomatic therapy. Recent research has introduced exciting new theories regarding the pathogenesis of preeclampsia. Clinical and experimental evidence implicating the circulating antiangiogenic molecules soluble Fms-like tyrosine kinase-1 (sFLT-1) and soluble endoglin (sENG), as well as endothelin-1 and the angiotensin II receptor type I autoimmune antibody (AT-1AA), have been especially promising. This review collates evidence for a role of hypoxia and hypoxia-inducible factor-1alpha (HIF1A; referred to as HIF-1α throughout) in the pathogenesis of preeclampsia and discusses possible molecular links between hypoxia and the newly reported potential mediators of the diseases manifestations.

Abnormalities in Oxygen Sensing Define Early and Late Onset Preeclampsia as Distinct Pathologies

Background The pathogenesis of preeclampsia, a serious pregnancy disorder, is still elusive and its treatment empirical. Hypoxia Inducible Factor-1 (HIF-1) is crucial for placental development and early detection of aberrant regulatory mechanisms of HIF-1 could impact on the diagnosis and management of preeclampsia. HIF-1α stability is controlled by O2-sensing enzymes including prolyl hydroxylases (PHDs), Factor Inhibiting HIF (FIH), and E3 ligases Seven In Absentia Homologues (SIAHs). Here we investigated early- (E-PE) and late-onset (L-PE) human preeclamptic placentae and their ability to sense changes in oxygen tension occurring during normal placental development. Methods and Findings Expression of PHD2, FIH and SIAHs were significantly down-regulated in E-PE compared to control and L-PE placentae, while HIF-1α levels were increased. PHD3 expression was increased due to decreased FIH levels as demonstrated by siRNA FIH knockdown experiments in trophoblastic JEG-3 cells. E-PE tissues had markedly diminished HIF-1α hydroxylation at proline residues 402 and 564 as assessed with monoclonal antibodies raised against hydroxylated HIF-1α P402 or P564, suggesting regulation by PHD2 and not PHD3. Culturing villous explants under varying oxygen tensions revealed that E-PE, but not L-PE, placentae were unable to regulate HIF-1α levels because PHD2, FIH and SIAHs did not sense a hypoxic environment. Conclusion Disruption of oxygen sensing in E-PE vs. L-PE and control placentae is the first molecular evidence of the existence of two distinct preeclamptic diseases and the unique molecular O2-sensing signature of E-PE placentae may be of diagnostic value when assessing high risk pregnancies and their severity.

Effects of Hypoxia-Inducible Factor-1α Overexpression in Pregnant Mice: Possible Implications for Preeclampsia and Intrauterine Growth Restriction

Preeclampsia and intrauterine growth restriction (IUGR) are pregnancy-specific disorders that share a common pathophysiology. Hypoxia-inducible factor-1α (HIF-1α) is a transcription factor that plays an important role in placental development. HIF-1α is elevated in preeclamptic placentas and induces soluble vascular endothelial growth factor receptor-1 (sFLT-1), a central factor in preeclampsia and IUGR pathogenesis. Our objective was to investigate the effects of HIF-1α overexpression on pregnancy in mice. C57BL/6J pregnant mice were systemically administered either adenovirus expressing stabilized HIF-1α (cytomegalovirus [CMV]-HIF), luciferase control (CMV-Luc), or saline on gestational day 8. Pregnant mice overexpressing HIF-1α had significantly elevated blood pressure and proteinuria compared with pregnant controls. HIF-1α mice showed fetal IUGR, decreased placental weights, and histopathological placental abnormalities compared with control mice. Glomerular endotheliosis, the hallmark lesion of preeclampsia, was demonstrated in the kidneys of these mice relative to the normal histology in control mice. Moreover, liver enzyme levels were significantly elevated, whereas complete blood counts revealed significant anemia and thrombocytopenia in CMV-HIF mice compared with controls. Blood smears confirmed microangiopathic hemolytic anemia in CMV-HIF mice, consistent with HELLP (hemolysis, elevated liver enzymes, and low platelets)-like syndrome. CMV-HIF mice showed elevation in serum sFLT-1 and soluble endoglin, providing a mechanistic explanation for the observations. Collectively, our results suggest a possible role for HIF-1α in the pathogenesis of both preeclampsia and IUGR.

Antimüllerian hormone as predictor of implantation and clinical pregnancy after assisted conception: a systematic review and meta-analysis

OBJECTIVE To assess whether antimüllerian hormone (AMH) is a predictor of implantation and/or clinical pregnancy in women undergoing assisted reproductive technology. DESIGN Systematic review and meta-analysis. SETTING Not applicable. PATIENT(S) Women undergoing IVF/intracytoplasmic sperm injection in nondonor cycles. INTERVENTION(S) Measurement of serum AMH level. MAIN OUTCOME MEASURE(S) Diagnostic odds ratio (OR) and summary receiver operating characteristic curve (AUC) for AMH as a predictor of implantation and/or clinical pregnancy. RESULT(S) A total of 525 observational studies were identified, of which 19 were selected (comprising 5,373 women). Studies reporting clinical pregnancy rates in women with unspecified ovarian reserve (n = 11), diminished ovarian reserve (DOR) (n = 4), and polycystic ovary syndrome (n = 4) were included, together with studies reporting implantation rates (n = 4). The OR for AMH as a predictor of implantation in women with unspecified ovarian reserve (n = 1,591) was 1.83 (95% confidence interval [CI] 1.49-2.25), whereas the AUC was 0.591 (95% CI 0.563-0.618). The OR for AMH as a predictor of clinical pregnancy in these women (n = 4,324) was 2.10 (95% CI 1.82-2.41), whereas the AUC was 0.634 (95% CI 0.618-0.650). The predictive ability of AMH for pregnancy was greatest in women with DOR (n = 615), with OR and AUC of 3.96 (95% CI 2.57-6.10) and 0.696 (95% CI 0.641-0.751), respectively. In contrast, AMH had no significant predictive ability in women with PCOS (n = 414), with OR and AUC of 1.18 (95% CI 0.53-2.62) and 0.600 (95% CI 0.547-0.653), respectively. CONCLUSION(S) Antimüllerian hormone has weak association with implantation and clinical pregnancy rates in assisted reproductive technology but may still have some clinical utility in counseling women undergoing fertility treatment regarding pregnancy rates, particularly those with DOR.

The role of angiogenic factors in fibroid pathogenesis: potential implications for future therapy

BACKGROUND It is well established that tumors are dependent on angiogenesis for their growth and survival. Although uterine fibroids are known to be benign tumors with reduced vascularization, recent work demonstrates that the vasculature of fibroids is grossly and microscopically abnormal. Accumulating evidence suggests that angiogenic growth factor dysregulation may be implicated in these vascular and other features of fibroid pathophysiology. METHODS Literature searches were performed in PubMed and Google Scholar for articles with content related to angiogenic growth factors and myometrium/leiomyoma. The findings are hereby reviewed and discussed. RESULTS Multiple growth factors involved in angiogenesis are differentially expressed in leiomyoma compared with myometrium. These include epidermal growth factor (EGF), heparin-binding-EGF, vascular endothelial growth factor, basic fibroblast growth factor, platelet-derived growth factor, transforming growth factor-β and adrenomedullin. An important paradox is that although leiomyoma tissues are hypoxic, leiomyoma feature down-regulation of key molecular regulators of the hypoxia response. Furthermore, the hypoxic milieu of leiomyoma may contribute to fibroid development and growth. Notably, common treatments for fibroids such as GnRH agonists and uterine artery embolization (UAE) are shown to work at least partly via anti-angiogenic mechanisms. CONCLUSIONS Angiogenic growth factors play an important role in mechanisms of fibroid pathophysiology, including abnormal vasculature and fibroid growth and survival. Moreover, the fibroids abnormal vasculature together with its aberrant hypoxic and angiogenic response may make it especially vulnerable to disruption of its vascular supply, a feature which could be exploited for treatment. Further experimental studies are required in order to gain a better understanding of the growth factors that are involved in normal and pathological myometrial angiogenesis, and to assess the potential of anti-angiogenic treatment strategies for uterine fibroids.

Potential mechanisms for racial and ethnic differences in antimullerian hormone and ovarian reserve.

Accumulating evidence suggests that reproductive potential and function may be different across racial and ethnic groups. Racial differences have been demonstrated in pubertal timing, infertility, outcomes after assisted reproductive technology (ART) treatment, and reproductive aging. Recently, racial differences have also been described in serum antimüllerian hormone (AMH), a sensitive biomarker of ovarian reserve, supporting the notion that ovarian reserve differs between racial/ethnic groups. The existence of such racial/ethnic differences in ovarian reserve, as reflected by AMH, may have important clinical implications for reproductive endocrinologists. However, the mechanisms which may underlie such racial differences in ovarian reserve are unclear. Various genetic factors and environmental factors such as obesity, smoking, and vitamin D deficiency which have been shown to correlate with serum AMH levels and also display significant racial/ethnic variations are discussed in this review. Improving our understanding of racial differences in ovarian reserve and their underlying causes may be essential for infertility treatment in minority women and lead to better reproductive planning, improved treatment outcomes, and timely interventions which may prolong reproductive lifespan in these women.

Endothelial-targeted gene transfer of hypoxia-inducible factor-1α augments ischemic neovascularization following systemic administration

Hypoxia-inducible factor-1α (HIF-1α) is a key regulator of the response to low oxygen levels and has been used for therapeutic angiogenesis. Various routes of administration have been used for delivering genes to the ischemic region including the intramuscular (IM) and intraarterial routes. When compared with these delivery methods, the intravenous (IV) route confers many advantages, including less invasiveness and lower cost. However, its use is hampered by the fact that it does not result in specific and robust tissue expression of the genes. Our aim was to determine the feasibility, safety, and therapeutic efficacy of systemic administration of adenoviral-mediated HIF-1α targeted to the endothelium. Using confocal microscopy and biodistribution studies we demonstrated that a modified murine preproendothelin-1 promoter (PPE1-3x) can target gene expression specifically to endothelial cells within ischemic muscle following systemic IV administration in C57BL/6 mice. Accordingly, an adenovirus expressing a PPE1-3x-regulated stabilized HIF-1α molecule, further activated by constitutive activation of its C-transactivation domain (C-TAD), was created. Systemic tail-vein administration of this adenovirus in a mouse hindlimb ischemia model resulted in enhanced blood perfusion, improved clinical outcome, and increased capillary density without systemic toxicity, in contrast to the profound systemic side effects and lack of therapeutic efficacy following cytomegalovirus (CMV)-regulated HIF-1α administration. Collectively, these data suggest that transcriptionally controlled systemic proangiogenic gene therapy is feasible, safe, and efficacious.Hypoxia-inducible factor-1alpha (HIF-1alpha) is a key regulator of the response to low oxygen levels and has been used for therapeutic angiogenesis. Various routes of administration have been used for delivering genes to the ischemic region including the intramuscular (IM) and intraarterial routes. When compared with these delivery methods, the intravenous (IV) route confers many advantages, including less invasiveness and lower cost. However, its use is hampered by the fact that it does not result in specific and robust tissue expression of the genes. Our aim was to determine the feasibility, safety, and therapeutic efficacy of systemic administration of adenoviral-mediated HIF-1alpha targeted to the endothelium. Using confocal microscopy and biodistribution studies we demonstrated that a modified murine preproendothelin-1 promoter (PPE1-3x) can target gene expression specifically to endothelial cells within ischemic muscle following systemic IV administration in C57BL/6 mice. Accordingly, an adenovirus expressing a PPE1-3x-regulated stabilized HIF-1alpha molecule, further activated by constitutive activation of its C-transactivation domain (C-TAD), was created. Systemic tail-vein administration of this adenovirus in a mouse hindlimb ischemia model resulted in enhanced blood perfusion, improved clinical outcome, and increased capillary density without systemic toxicity, in contrast to the profound systemic side effects and lack of therapeutic efficacy following cytomegalovirus (CMV)-regulated HIF-1alpha administration. Collectively, these data suggest that transcriptionally controlled systemic proangiogenic gene therapy is feasible, safe, and efficacious.

Microbiota and pelvic inflammatory disease.

Female genital tract microbiota play a crucial role in maintaining health. Disequilibrium of the microbiota has been associated with increased risk of pelvic infections. In recent years, culture-independent molecular techniques have expanded understanding of the composition of genital microbiota and the dynamic nature of the microbiota. There is evidence that upper genital tract may not be sterile and may harbor microflora in the physiologic state. The isolation of bacterial vaginosis-associated organisms in women with genital infections establishes a link between pelvic infections and abnormal vaginal flora. With the understanding of the composition of the microbiota in healthy and diseased states, the next logical step is to identify the function of the newly identified microbes. This knowledge will further expand our understanding of the causation of pelvic infections, which may lead to more effective prevention and treatment strategies.

The Effects of External Counter Pulsation Therapy on Circulating Endothelial Progenitor Cells in Patients with Angina Pectoris

Objectives: External counter pulsation therapy (ECPT) offers symptomatic relief and improves ischemia in patients with refractory angina pectoris. We aimed to determine the effects of ECPT on circulating endothelial progenitor cells (EPCs). Methods: We prospectively studied 25 patients with angina pectoris treated with ECPT (n = 15) or receiving standard care (n = 10). The number of EPCs positive for CD34 and kinase insert domain receptor (KDR) was determined by flow cytometry and the number of colony-forming units (CFUs) was assessed in a 7-day culture, before ECPT and after 9 weeks. Results: ECPT improved anginal score from a median of 3.0 to 2.0 (p < 0.001). Concomitantly, ECPT increased EPC number from a median of 10.2 to 17.8/105 mononuclear cells (p < 0.05), and CFUs from 3.5 to 11.0 (p = 0.01). Flow-mediated dilatation was improved by ECPT from 7.4 to 12.2% (p < 0.001) and correlated with EPC-CFUs (r = 0.461, p = 0.027). The levels of asymmetric dimethylarginine were reduced by ECPT from 0.70 to 0.60 µmol/l (p < 0.01). In contrast, the same parameters did not change in the control group, before and after follow-up. Conclusions: The present pilot study shows, for the first time, that ECPT is associated with increased number and colony-forming capacity of circulating EPCs.

Vitamin D Supplementation Decreases TGF-β1 Bioavailability in PCOS: A Randomized Placebo-Controlled Trial

CONTEXT There is an abnormal increase in TGF-β1 bioavailability in women with polycystic ovary syndrome (PCOS), which might play a role in the pathophysiology of this syndrome. Vitamin D (VD) supplementation improves various clinical manifestations of PCOS and decreases TGF-β1 levels in several diseases including myelofibrosis. OBJECTIVE The objective of the study was to determine the effect of VD supplementation on TGF-β1 bioavailability in VD-deficient women with PCOS and assess whether changes in TGF-β1/soluble endoglin (sENG) levels correlate with an improvement in PCOS clinical manifestations. DESIGN This was a prospective, randomized, placebo-controlled trial. SETTING The study was conducted at an academic-affiliated medical center. PARTICIPANTS Sixty-eight VD-deficient women with PCOS who were not pregnant or taking any exogenous hormones were recruited between October 2013 and January 2015. INTERVENTIONS Forty-five women received 50 000 IU of oral vitamin D3 and 23 women received oral placebo once weekly for 8 weeks. MAIN OUTCOMES MEASURES Serum TGF-β1, sENG, lipid profile, testosterone, dehydroepiandrosterone sulfate, and insulin resistance were measured. The clinical parameters were evaluated before and 2 months after treatment. RESULTS The VD level significantly increased and normalized after VD supplementation (16.3 ± 0.9 [SEM] to 43.2 ± 2.4 ng/mL; P < .01), whereas it did not significantly change after placebo. After the VD supplementation, there was a significant decrease in the following: the interval between menstrual periods (80 ± 9 to 60 ± 6 d; P = .04), Ferriman-Gallwey score (9.8 ± 1.5 to 8.1 ± 1.5; P < .01), triglycerides (138 ± 22 to 117 ± 20 mg/dL; P = .03), and TGF-β1 to sENG ratio (6.7 ± 0.4 to 5.9 ± 0.4; P = .04). In addition, the ΔTGF-β1 to sENG ratio was positively correlated with Δtriglycerides (r = 0.59; P = .03). CONCLUSIONS VD supplementation in VD-deficient women with PCOS significantly decreases the bioavailability of TGF-β1, which correlates with an improvement in some abnormal clinical parameters associated with PCOS. This is a novel mechanism that could explain the beneficial effects of VD supplementation in women with PCOS. These findings may support new treatment modalities for PCOS, such as the development of anti-TGF-β drugs.