Preeclampsia and Obesity-The Preventive Role of Exercise

Obesity is now recognized as a worldwide epidemic. An inadequate diet and reduced physical activity are acknowledged as the leading causes of excess body weight. Despite growing evidence that obesity is a risk factor for unsuccessful pregnancies, almost half of all women who become pregnant today are overweight or obese. Common complications of pregnancy in this group of women are preeclampsia and gestational hypertension. These conditions are also observed more frequently in women with excessive weight gain during pregnancy. Preeclampsia is one of the most serious pregnancy complications with an unpredictable course, which in its most severe forms, threatens the life and health of the mother and her baby. The early identification of the risk factors for preeclampsia development, including obesity, allows for the implementation of prophylaxis and a reduction in maternal and fetal complications risk. Additionally, preeclampsia and obesity are the recognized risk factors for developing cardiovascular disease in later life, so prophylaxis and treating obesity are paramount for their prevention. Thus, a proper diet and physical activity might play an essential role in the prophylaxis of preeclampsia in this group of women. Limiting weight gain during pregnancy and modifying the metabolic risk factors with regular physical exercise creates favorable metabolic conditions for pregnancy development and benefits the elements of the pathogenetic sequence for preeclampsia development. In addition, it is inexpensive, readily available and, in the absence of contraindications to its performance, safe for the mother and fetus. However, for this form of prevention to be effective, it should be applied early in pregnancy and, for overweight and obese women, proposed as an essential part of planning pregnancy. This paper aims to present the mechanisms of the development of hypertension in pregnancy in obese women and the importance of exercise in its prevention.

Endothelial Glycocalyx

The glycocalyx is a polysaccharide structure that protrudes from the body of a cell. It is primarily conformed of glycoproteins and proteoglycans, which provide communication, electrostatic charge, ionic buffering, permeability, and mechanosensation-mechanotransduction capabilities to cells. In blood vessels, the endothelial glycocalyx that projects into the vascular lumen separates the vascular wall from the circulating blood. Such a physical location allows a number of its components, including sialic acid, glypican-1, heparan sulfate, and hyaluronan, to participate in the mechanosensation-mechanotransduction of blood flow-dependent shear stress, which results in the synthesis of nitric oxide and flow-mediated vasodilation. The endothelial glycocalyx also participates in the regulation of vascular permeability and the modulation of inflammatory responses, including the processes of leukocyte rolling and extravasation. Its structural architecture and negative charge work to prevent macromolecules greater than approximately 70 kDa and cationic molecules from binding and flowing out of the vasculature. This also prevents the extravasation of pathogens such as bacteria and virus, as well as that of tumor cells. Due to its constant exposure to shear and circulating enzymes such as neuraminidase, heparanase, hyaluronidase, and matrix metalloproteinases, the endothelial glycocalyx is in a continuous process of degradation and renovation. A balance favoring degradation is associated with a variety of pathologies including atherosclerosis, hypertension, vascular aging, metastatic cancer, and diabetic vasculopathies. Consequently, ongoing research efforts are focused on deciphering the mechanisms that promote glycocalyx degradation or limit its syntheses, as well as on therapeutic approaches to improve glycocalyx integrity with the goal of reducing vascular disease. © 2022 American Physiological Society. Compr Physiol 12: 1-31, 2022.

Prevention of Hypertensive Disorders of Pregnancy-Is There a Place for Metformin?

The possibility of prophylaxis of hypertensive disorders of pregnancy (HDPs) such as preeclampsia (PE) and pregnancy-induced hypertension is of interest due to the unpredictable course of these diseases and the risks they carry for both mother and fetus. It has been proven that their development is associated with the presence of the placenta, and the processes that initiate it begin at the time of the abnormal invasion of the trophoblast in early pregnancy. The ideal HDP prophylaxis should alleviate the influence of risk factors and, at the same time, promote physiological trophoblast invasion and maintain the physiologic endothelium function without any harm to both mother and fetus. So far, aspirin is the only effective and recommended pharmacological agent for the prevention of HDPs in high-risk groups. Metformin is a hypoglycemic drug with a proven protective effect on the cardiovascular system. Respecting the anti-inflammatory properties of metformin and its favorable impact on the endothelium, it seems to be an interesting option for HDP prophylaxis. The results of previous studies on such use of metformin are ambiguous, although they indicate that in a certain group of pregnant women, it might be effective in preventing hypertensive complications. The aim of this study is to present the possibility of metformin in the prevention of hypertensive disorders of pregnancy with respect to its impact on the pathogenic elements of development

Reduction of serum-induced endothelial STAT3(Y705) activation is associated with preeclampsia

OBJECTIVES

Preeclampsia is associated with maternal morbidity and mortality during pregnancy, and also an increased cardiovascular disease (CVD) risk later in life. During preeclampsia, alterations in secreted placental factors leading to systemic maternal endothelial dysfunction are evident. However, little is known about the associated endothelial intracellular signaling. STAT3 is a latent cytoplasmic transcription factor involved in endothelial cell differentiation, survival, and angiogenesis. We aimed to test if preeclampsia and preeclampsia-related placental factors could alter serum-induced STAT3(Y705) activation in endothelial cells. Furthermore, if altered serum-induced endothelial STAT3 (Y705) activation is related to post-preeclamptic CVD risk.

STUDY DESIGN

HUVECs were used as a model of maternal endothelium. Experiments entailed addition of 20% human pregnancy serum as well as addition of recombinant PlGF, sFLT1 and VEGF-A_165a to the cells.

MAIN OUTCOME MEASURES

Levels of pSTAT3(Y705) related to STAT3 levels were evaluated by immunoblotting analysis.

RESULTS

Our results show that preeclamptic serum induces significantly lower STAT3(Y705) phosphorylation compared with uncomplicated pregnancy serum (P = 0.0089) in endothelial cells. Furthermore, STAT3(Y705) phosphorylation was not changed upon addition of PlGF, sFLT1, or VEGF-A_165a together with pregnancy sera compared with sera alone. Finally, sera from women with previous preeclampsia and current hypertension and carotid atherosclerotic plaques show significantly lower STAT3(Y705) phosphorylation capabilities compared with healthy women with previous uncomplicated pregnancies 8-18 years after deliveries (P = 0.029).

CONCLUSIONS

Reduction in serum-induced endothelial STAT3(Y705) activation may play an important role in the preeclampsia-associated endothelial dysfunction. Additionally, reduced endothelial STAT3(Y705) phosphorylation may contribute to increased post-preeclamptic CVD risk 8-18 years after delivery.

Imaging of Atypical and Complicated Posterior Reversible Encephalopathy Syndrome

Posterior reversible encephalopathy syndrome (PRES) is a condition clinically characterized by headache, altered mental status, seizures, and visual loss and may be associated with systemic hypertension, preeclampsia/eclampsia, chemotherapy, immunosuppressive therapies in the setting of organ transplantation, and uremic encephalopathy. While brain imaging in patients with PRES typically reveals symmetric vasogenic edema within the parietal and occipital lobes, PRES may present with atypical imaging findings such as central brainstem and deep gray involvement without subcortical edema, and even spinal cord involvement. Additionally, PRES may be complicated in some cases by the presence of cytotoxic edema and hemorrhage. This review will serve to summarize the pathophysiologic theories and controversies underlying PRES, imaging features encountered in atypical and complicated PRES, and the implications these findings may have on patient prognosis.

The VEGF-A exon 8 splicing-sensitive fluorescent reporter mouse is a novel tool to assess the effects of splicing regulatory compounds in vivo

Vascular endothelial growth factor (VEGF)-A is differentially spliced to give two functionally different isoform families; pro-angiogenic, pro-permeability VEGF-A_xxx and anti-angiogenic, anti-permeability VEGF-A_xxxb. VEGF-A splicing is dysregulated in several pathologies, including cancer, diabetes, and peripheral arterial disease. The bichromatic VEGF-A splicing-sensitive fluorescent reporter harboured in a transgenic mouse is a novel approach to investigate the splicing patterns of VEGF-A in vivo. We generated a transgenic mouse harbouring a splicing-sensitive fluorescent reporter designed to mimic VEGF-A terminal exon splicing (VEGF8ab) by insertion into the ROSA26 genomic locus. dsRED expression denotes proximal splice site selection (VEGF-A_xxx) and eGFP expression denotes distal splice site selection (VEGF-A_xxxb). We investigated the tissue-specific expression patterns in the eye, skeletal muscle, cardiac muscle, kidney, and pancreas, and determined whether the splicing pattern could be manipulated in the same manner as endogenous VEGF-A by treatment with the SRPK1 inhibitor SPHINX 31. We confirmed expression of both dsRED and eGFP in the eye, skeletal muscle, cardiac muscle, kidney, and pancreas, with the highest expression of both fluorescent proteins observed in the exocrine pancreas. The ratio of dsRED and eGFP matched that of endogenous VEGF-A_xxx and VEGF-A_xxxb. Treatment of the VEGF8ab mice with SPHINX 31 increased the mRNA and protein eGFP/dsRED ratio in the exocrine pancreas, mimicking endogenous VEGF-A splicing. The VEGF-A exon 8 splicing-sensitive fluorescent reporter mouse is a novel tool to assess splicing regulation in the individual cell-types and tissues, which provides a useful screening process for potentially therapeutic splicing regulatory compounds in vivo.

Inhibition of HIF-1a-mediated TLR4 activation decreases apoptosis and promotes angiogenesis of placental microvascular endothelial cells during severe pre-eclampsia pathogenesis

OBJECTIVE

Hypoxia-induced factor 1a (HIF-1a) and Toll-like receptor 4 (TLR4) are involved in pre-eclampsia (PE) pathogenesis. However, little is known about their relationships. This study aimed to investigate the interaction of HIF-1a and TLR4 in PE pathogenesis.

METHODS

The expression of HIF-1a and TLR4 were analyzed by qRT-PCR. Celluar PE model was established by hypoxia/reoxygenation treatment of human placental microvascular endothelial cells (hPMEC). Cell proliferation, apoptosis, invasion and migration were analyzed by CCK-8, flow cytometry, Transwell and scratch adhesion test, respectively. Angiogenesis was performed by tube formation, Ang-1 in culture supernatant was analyzed by ELISA.

RESULTS

HIF-1a and TLR4 expression were significantly elevated in placental tissues from early-onset and late-onset severe pre-eclampsia patients compared with control, with increased Bax, TRIF and PUMA, and decreased Bcl-2 and VEGFA; Down-regulation of HIF-1a expression decreased TLR4 expression, promoted proliferation, invasion, migration and angiogenesis but suppressed apoptosis in cellular model. In addition, silencing HIF-1a and TAK232 treatment synergically promoted some more proliferation, invasion, migration and angiogenesis but suppressed apoptosis in cellular model.

CONCLUSION

HIF-1a could promote hPMEC apoptosis by regulating TLR4 expression during PE pathogenesis.

Regulation of human feto-placental endothelial barrier integrity by vascular endothelial growth factors: competitive interplay between VEGF-A165a, VEGF-A165b, PIGF and VE-cadherin

The human placenta nourishes and protects the developing foetus whilst influencing maternal physiology for fetal advantage. It expresses several members of the vascular endothelial growth factor (VEGF) family including the pro-angiogenic/pro-permeability VEGF-A₁₆₅a isoform, the anti-angiogenic VEGF-A₁₆₅b, placental growth factor (PIGF) and their receptors, VEGFR1 and VEGFR2. Alterations in the ratio of these factors during gestation and in complicated pregnancies have been reported; however, the impact of this on feto-placental endothelial barrier integrity is unknown. The present study investigated the interplay of these factors on junctional occupancy of VE-cadherin and macromolecular leakage in human endothelial monolayers and the perfused placental microvascular bed. Whilst VEGF-A₁₆₅a (50 ng/ml) increased endothelial monolayer albumin permeability (P<0.0001), equimolar concentrations of VEGF-A₁₆₅b (P>0.05) or PlGF (P>0.05) did not. Moreover, VEGF-A₁₆₅b (100 ng/ml; P<0.001) but not PlGF (100 ng/ml; P>0.05) inhibited VEGF-A₁₆₅a-induced permeability when added singly. PlGF abolished the VEGF-A₁₆₅b-induced reduction in VEGF-A₁₆₅a-mediated permeability (P>0.05); PlGF was found to compete with VEGF-A₁₆₅b for binding to Flt-1 at equimolar affinity. Junctional occupancy of VE-cadherin matched alterations in permeability. In the perfused microvascular bed, VEGF-A₁₆₅b did not induce microvascular leakage but inhibited and reversed VEGF-A₁₆₅a-induced loss of junctional VE-cadherin and tracer leakage. These results indicate that the anti-angiogenic VEGF-A₁₆₅b isoform does not increase permeability in human placental microvessels or HUVEC primary cells and can interrupt VEGF-A₁₆₅a-induced permeability. Moreover, the interplay of these isoforms with PIGF (and s-flt1) suggests that the ratio of these three factors may be important in determining the placental and endothelial barrier in normal and complicated pregnancies.

Immune system activation in the pathogenesis of posterior reversible encephalopathy syndrome

Posterior reversible encephalopathy syndrome (PRES) is a clinical-radiological syndrome characterized by a variable combination of headaches, seizures, altered mental status, visual impairment, focal neurological signs and symmetric vasogenic edema in bilateral posterior cerebral circulation territory. The pathogenesis of PRES is still controversial. Most of the clinical conditions associated with PRES involve a systemic toxicity response in the entire organism with activation of the cells of the immune system and cytokines. These PRES related conditions induce T cell activation, cytokine release, and subsequent leukocyte adhesion and activation, resulting in endothelial damage and fluid leakage. This potential mechanism of immune system activation and endothelial dysfunction may play a critical role in the pathogenesis of PRES. In this review, the role of immune system activation and endothelial dysfunction in the pathogenesis of PRES is discussed, with the aim to improve our understanding of this disorder.

Risk factors for central serous chorioretinopathy in pregnant Japanese women

AIM

This study was performed to determine risk factors for central serous chorioretinopathy (CSC) in pregnant women.

METHODS

This retrospective observational study was performed in a cohort of all 1881 women giving birth at a single center. The hospital database was searched to abstract all women diagnosed with pre-eclampsia (PE) as well as those visiting the eye clinic during the current pregnancy. Medical chart review was performed in all women diagnosed with CSC and PE.

RESULTS

PE developed in 73 (3.9%) women, six (8.2%) of whom visited the eye clinic for problems occurring in the current pregnancy; 47 of 1808 (2.6%) women without PE visited the eye clinic (P  = 0.015). Four women were identified as having developed CSC after onset of PE, and none of those without PE developed CSC (5.5% [4/73] vs 0.0% [0/1808], respectively, P <  0.0001). Stepwise regression analysis selected four risk factors for CSC: hematocrit value > 38.0% (odds ratio [OR], 22.9; 95% confidence interval [CI], 2.12-247), serum creatinine > 0.7 mg/dL (OR, 21.7; 95%CI, 1.12-422), time interval from diagnosis of PE until delivery > 14 days (OR, 20.0; 95%CI, 1.87-214), and urine protein : creatinine ratio (mg/mg) > 4.5 (OR, 15.7; 95%CI, 0.81-304). Hematocrit value > 38.0% was finally identified as the only independent risk factor (OR, 22.9; 95%CI, 2.12-1716) for CSC in PE women.

CONCLUSION

CSC was likely to occur in PE women, especially in those with hemoconcentration as a result of plasma leakage from the circulating blood due to increased vascular permeability.

VEGF165b Modulates Endothelial VEGFR1-STAT3 Signaling Pathway and Angiogenesis in Human and Experimental Peripheral Arterial Disease

RATIONALE

Atherosclerotic-arterial occlusions decrease tissue perfusion causing ischemia to lower limbs in patients with peripheral arterial disease (PAD). Ischemia in muscle induces an angiogenic response, but the magnitude of this response is frequently inadequate to meet tissue perfusion requirements. Alternate splicing in the exon-8 of vascular endothelial growth factor (VEGF)-A results in production of proangiogenic VEGF_xxxa isoforms (VEGF₁₆₅a, 165 for the 165 amino acid product) and antiangiogenic VEGF_xxxb (VEGF₁₆₅b) isoforms.

OBJECTIVE

The antiangiogenic VEGF_xxxb isoforms are thought to antagonize VEGF_xxxa isoforms and decrease activation of VEGF receptor-2 (VEGFR2), hereunto considered the dominant receptor in postnatal angiogenesis in PAD. Our data will show that VEGF₁₆₅b inhibits VEGFR1 signal transducer and activator of transcription (STAT)-3 signaling to decrease angiogenesis in human and experimental PAD.

METHODS AND RESULTS

In human PAD versus control muscle biopsies, VEGF₁₆₅b: (1) is elevated, (2) is bound higher (versus VEGF₁₆₅a) to VEGFR1 not VEGFR2, and (3) levels correlated with decreased VEGFR1, not VEGFR2, activation. In experimental PAD, delivery of an isoform-specific monoclonal antibody to VEGF₁₆₅b versus control antibody enhanced perfusion in animal model of severe PAD (Balb/c strain) without activating VEGFR2 signaling but with increased VEGFR1 activation. Receptor pull-down experiments demonstrate that VEGF₁₆₅b inhibition versus control increased VEGFR1-STAT3 binding and STAT3 activation, independent of Janus-activated kinase-1)/Janus-activated kinase-2. Using VEGFR1^+/- mice that could not increase VEGFR1 after ischemia, we confirm that VEGF₁₆₅b decreases VEGFR1-STAT3 signaling to decrease perfusion.

CONCLUSIONS

Our results indicate that VEGF₁₆₅b prevents activation of VEGFR1-STAT3 signaling by VEGF₁₆₅a and hence inhibits angiogenesis and perfusion recovery in PAD muscle.

An Overview of VEGF-Mediated Signal Transduction

Vascular endothelial growth factor (VEGF) plays a fundamental role in angiogenesis and endothelial cell biology, and has been the subject of intense study as a result. VEGF acts via a diverse and complex range of signaling pathways, with new targets constantly being discovered. This review attempts to summarize the current state of knowledge regarding VEGF cell signaling in endothelial and cardiovascular biology, with a particular emphasis on its role in angiogenesis.

VEGF Splicing and the Role of VEGF Splice Variants: From Physiological-Pathological Conditions to Specific Pre-mRNA Splicing

During this past decade, the vascular endothelial growth factor (VEGF) pathway has been extensively studied. VEGF is a paradigm of molecular regulation since its expression is controlled at all possible steps including transcription, mRNA stability, translation, and pre-mRNA splicing. The latter form of molecular regulation is probably the least studied. This field has been neglected; yet different forms of VEGF with different sizes and different physiological properties issued from alternative splicing have been described a long time ago. Recently a new level of complexity was added to the field of splicing of VEGF pre-mRNA. Whereas thousands of publications have described VEGF as a pro-angiogenic factor, an alternative splicing event generates specific anti-angiogenic forms of VEGF that only differ from the others by a modification in the last six amino acids of the protein. According to the scientists who discovered these isoforms, which are indistinguishable from the pro-angiogenic ones with pan VEGF antibodies, some of the literature on VEGF is at least inexact if not completely false. Moreover, the presence of anti-angiogenic forms of VEGF may explain the disappointing efficacy of anti-VEGF therapies on the overall survival of patients with different forms of cancers and with wet age-related macular degeneration. This review focuses on the existence of the different alternative splice variants of VEGF and the molecular mechanisms associated with their expression and function.

The role of VEGF 165b in pathophysiology

Anti-angiogenic vascular endothelial growth factor A (VEGF) 165b and pro-angiogenic VEGF 165 are generated from the same transcript, and their relative amounts are dependent on alternative splicing. The role of VEGF 165b has not been investigated in as much detail as VEGF 165, although it appears to be highly expressed in non-angiogenic tissues and, in contrast with VEGF 165, is downregulated in tumors and other pathologies associated with abnormal neovascularization such as diabetic retinopathy or Denys Drash syndrome. VEGF 165b inhibits VEGFR2 signaling by inducing differential phosphorylation, and it can be used to block angiogenesis in in vivo models of tumorigenesis and angiogenesis-related eye disease. Recent reports have identified three serine/arginine-rich proteins, SRSF1, SRSF2 and SRSF6, and studied their role in regulating terminal splice-site selection. Since the balance of VEGF isoforms is lost in cancer and angiogenesis-related conditions, control of VEGF splicing could also be used as a basis for therapy in these diseases.

Hyperbaric oxygen therapy: can it prevent irradiation-induced necrosis?

Radiosurgery is an important non-invasive procedure for the treatment of tumors and vascular malformations. However, in addition to killing target tissues, cranial irradiation induces damage to adjacent healthy tissues leading to neurological deterioration in both pediatric and adult patients, which is poorly understood and insufficiently treatable. To minimize irradiation damage to healthy tissue, not the optimal therapeutic irradiation dose required to eliminate the target lesion is used but lower doses. Although the success rate of irradiation surgery is about 95%, 5% of patients suffer problems, most commonly neurological, that are thought to be a direct consequence of irradiation-induced inflammation. Although no direct correlation has been demonstrated, the appearance and disappearance of inflammation that develops following irradiation commonly parallel the appearance and disappearance of neurological side effects that are associated with the neurological function of the irradiated brain regions. These observations have led to the hypothesis that brain inflammation is causally related to the observed neurological side effects. Studies indicate that hyperbaric oxygen therapy (HBOT) applied after the appearance of irradiation-induced neurological side effects reduces the incidence and severity of those side effects. This may result from HBOT reducing inflammation, promoting angiogenesis, and influencing other cellular functions thereby suppressing events that cause the neurological side effects. However, it would be significantly better for the patient if rather than waiting for neurological side effects to become manifest they could be avoided. This review examines irradiation-induced neurological side effects, methods that minimize or resolve those side effects, and concludes with a discussion of whether HBOT applied following irradiation, but before manifestation of neurological side effects may prevent or reduce the appearance of irradiation-induced neurological side effects.

An unexpected tail of VEGF and PlGF in pre-eclampsia

PET (pre-eclamptic toxaemia), characterized by pregnancy-related hypertension and proteinuria, due to widespread endothelial dysfunction, is a primary cause of maternal morbidity. Altered circulating factors, particularly the VEGF (vascular endothelial growth factor) family of proteins and their receptors, are thought to be key contributors to this disease. Plasma from patients with PET induces numerous cellular and physiological changes in endothelial cells, indicating the presence of a circulating imbalance of the normal plasma constituents. These have been narrowed down to macromolecules of the VEGF family of proteins and receptors. It has been shown that responses of endothelial cells in intact vessels to plasma from patients with pre-eclampsia is VEGF-dependent. It has recently been shown that this may be specific to the VEGF₁₆₅b isoform, and blocked by addition of recombinant human PlGF (placental growth factor). Taken together with results that show that sVEGFR1 (soluble VEGF receptor 1) levels are insufficient to bind VEGF-A in human plasma from patients with pre-eclampsia, and that other circulating macromolecules bind, but do not inactivate, VEGF-A, this suggests that novel hypotheses involving altered bioavailability of VEGF isoforms resulting from reduced or bound PlGF, or increased sVEGFR1 increasing biological activity of circulating plasma, could be tested. This suggests that knowing how to alter the balance of VEGF family members could prevent endothelial activation, and potentially some symptoms, of pre-eclampsia.