Endothelial dysfunction is associated with several lifestyle-related diseases, including cardiovascular and neurodegenerative diseases, and it contributes significantly to the global health burden. Recent research indicates a link between cardiovascular risk factors (CVRFs), excessive production of reactive oxygen species (ROS), mitochondrial impairment, and endothelial dysfunction. Circulating endothelial progenitor cells (EPCs) are recruited into the vessel wall to maintain appropriate endothelial function, repair, and angiogenesis. After attachment, EPCs differentiate into mature endothelial cells (ECs). Like ECs, EPCs are also susceptible to CVRFs, including metabolic dysfunction and chronic inflammation. Therefore, mitochondrial dysfunction of EPCs may have long-term effects on the function of the mature ECs into which EPCs differentiate, particularly in the presence of endothelial damage. However, a link between CVRFs and impaired mitochondrial function in EPCs has hardly been investigated. In this review, we aim to consolidate existing knowledge on the development of mitochondrial and endothelial dysfunction in the vascular endothelium, place it in the context of recent studies investigating the consequences of CVRFs on EPCs, and discuss the role of mitochondrial dysfunction. Thus, we aim to gain a comprehensive understanding of mechanisms involved in EPC deterioration in relation to CVRFs and address potential therapeutic interventions targeting mitochondrial health to promote endothelial function.

Recent research has highlighted the significance of succinate and its receptor in gestational diabetes (GDM) pathogenesis. However, a clear interconnection between placenta metabolism, succinate levels, SUCNR1 signalling and pregnancy pathologies remains elusive. Here, we set out to investigate the potential role of succinate on labour and placental mechanisms by combining clinical and functional experimental data at the same time as exploring the specific SUCNR1‐mediated effects of succinate on placenta vascularization, addressing its specific agonist actions. According to our data, succinate levels vary throughout pregnancy and postpartum, with a natural increase during the peripartum period. We also show that SUCNR1 activation in the umbilical cord endothelium promotes angiogenesis under normal conditions. However, in GDM, excessive succinate and impaired SUCNR1 function may weaken this angiogenic response. In conclusion, the present study underlines succinate as an emerging signalling molecule in the placenta, regulating labour and placental processes. The reduced sensitivity of the succinate/SUCNR1 pathway in the GDM environment may serve as a protective physiological mechanism or could have a pathogenic effect. image Key points: Succinate levels increase at delivery in maternal and fetal circulation. Gestational diabetes (GDM) induces succinate accumulation and SUCNR1 downregulation in umbilical cords. GDM compromises angiogenic gene profile modulation by SUCNR1 in umbilical cord endothelium. SUCNR1 activation stimulates sprouting and tube‐forming capacity of human umbilical vein endothelial cells from healthy, but not GDM pregnancies.

High gestational weight gain (GWG) is a cardiovascular risk factor and may disturb neonatal endothelial function. Long non-coding RNAs (lncRNAs) regulate gene expression epigenetically and can modulate endothelial function. Endothelial colony forming cells (ECFCs), circulating endothelial precursors, are a recruitable source of endothelial cells and sustain endothelial function, vascular growth and repair. We here investigated whether higher GWG affects neonatal ECFC function and elucidated the role of lncRNAs herein. Wound healing of umbilical cord blood-derived ECFCs after pregnancies with GWG versus >13 kg was determined in a scratch assay and based on monolayer impedance after electric wounding (electric cell-substrate impedance sensing, ECIS). LncRNA expression was analysed by RNA sequencing. The function of killer cell lectin-like receptor K1 antisense RNA (KLRK1-AS1) was investigated after siRNA-based knockdown. Closure of the scratch was delayed by 25% (P = 0.041) in the higher GWG group and correlated inversely with GWG (R = -0.538, P = 0.012) in all subjects (n = 22). Similarly, recovery of the monolayer barrier after electric wounding was delayed (-11% after 20 h; P = 0.014; n = 15). Several lncRNAs correlated with maternal GWG, the most significant one being KLRK1-AS1 (log(2) fold change = -0.135, P < 0.001, n = 35). KLRK1-AS1 knockdown (n = 4) reduced barrier recovery after electric wounding by 21% (P = 0.029) and KLRK1-AS1 expression correlated with the time required for wound healing for both scratch (R = 0.447, P = 0.033) and impedance-based assay (R = 0.629, P = 0.014). Higher GWG reduces wound healing of neonatal ECFCs, and lower levels of the lncRNA KLRK1-AS1 may underlie this.

Endothelial colony forming cells (ECFCs) are circulating progenitor cells essential for angiogenesis and vascular remodelling in pregnancy. ECFC numbers and outgrowth are often reduced with metabolic diseases and conditions associated with disturbed endothelial function. However, how pregnancy, a period of metabolic stress, affects ECFCs remains unclear. We isolated ECFCs from non‐pregnant women (NP, N = 28) and from women in early (EP, N = 23) and late (LP, N = 39) pregnancy using density gradient centrifugation. ECFC outgrowth was analysed in relation to markers of lipid and glucose metabolism (cholesterol, triglycerides, high‐density lipoprotein‐cholesterol, low‐density lipoprotein‐cholesterol, fasting glucose), endothelial function (interleukin‐6, E‐selectin, P‐selectin, intracellular adhesion molecule 1, vascular cell adhesion molecule 1, asymmetric dimethylarginine) and body composition (body mass index, body fat). ECFC morphology was microscopically assessed and scored from cobblestone‐like to spindle‐shaped. We found that ECFC outgrowth rate was higher in LP (60.9%) compared to EP (40.4%) and NP (49.1%). ECFC colony number and expansion rate were higher in LP than in EP and NP. ECFCs from NP donors had a more elongated morphology than ECFCs from pregnant donors. In EP, ECFCs predominantly derived from pregnancies with female fetuses, whereas the opposite was observed in LP. Higher interleukin‐6 and E‐selectin plasma levels, indicative of an inflammatory state, were associated with faster outgrowth, along with increased lipid levels. Gestational diabetes was associated with increased ECFC colony number compared to healthy pregnancy. These findings suggest that pregnancy alters ECFC characteristics, with late pregnancy marked by enhanced ECFC outgrowth and expansion, potentially reflecting vascular adaptation to metabolic and inflammatory changes. Our results underscore the potential role of ECFCs in maternal vascular health in pregnancy. image Key points: Pregnancy requires extensive vascular remodelling. Circulating endothelial progenitor cells are crucial for angiogenesis and vascular adaptations. In this study, we investigated the outgrowth of circulating endothelial colony forming cells from peripheral blood of non‐pregnant women, and of women in early and late pregnancy. We further correlated the outgrowth parameters with blood markers of endothelial function and with metabolic state. Our findings indicate that the outgrowth capacity of these cells is highest in late pregnancy and depends on fetal sex. Pregnancy‐induced markers of endothelial activation such as interleukin‐6 and E‐selectin, as well as markers of metabolism such as cholesterol and triglycerides, affect the outgrowth of endothelial colony forming cells. This study highlights the dynamic changes in endothelial colony forming cell abundance and morphology across different stages of pregnancy and their association with maternal metabolism and inflammation.

Background/Objectives: Inadequate cardiovascular adaptation during pregnancy impairs endothelial function and vascular resistance, contributing to complications such as pre-eclampsia (PE) and gestational hypertension (GH). Neprilysin (NEP), a protease involved in vascular regulation, has been linked to PE, but its role in endothelial function and vascular adaptation remains unclear. This pilot study investigates the associations between soluble neprilysin (sNEP) and markers of vascular and renal function in high-risk pregnancies without PE. Methods: Observed parameters were analyzed in 29 high-risk pregnant women across early, mid-, and late pregnancy. sNEP levels were analyzed alongside body mass index (BMI), endothelial dysfunction (ADMA), arterial stiffness (pulse wave velocity, PWV), retinal microvasculature (central retinal arteriolar and venular equivalents, CRAE and CRVE), and kidney function markers. The impact of gestational hypertension (GH) and prior smoking on sNEP levels was also evaluated. Results: In early and mid-pregnancy, sNEP was inversely associated with BMI. During mid-pregnancy, sNEP showed a positive correlation with CRAE and an inverse correlation with PWV, suggesting reduced arterial stiffness. By late pregnancy, sNEP was positively associated with glomerular filtration rate and inversely correlated with creatinine and protein levels, reflecting improved kidney function. Women with GH exhibited elevated sNEP, while former smokers had lower sNEP levels in early pregnancy. Conclusions: These findings suggest that sNEP plays a role in vascular and renal adaption during pregnancy, offering new perspectives on vascular tone regulation in high-risk pregnancies. Further research is needed to clarify these mechanisms and their clinical relevance.

Endothelial integrity is essential for cardiovascular health, and circulating endothelial progenitor cells, particularly endothelial colony-forming cells (ECFCs), are key contributors to vascular repair and maintenance. Long non-coding RNAs (lncRNAs) have emerged as novel epigenetic regulators of endothelial physiology and pathology. Building on our previous work identifying the lncRNA KLRK1-AS1 as a positive modulator of ECFC wound healing, we aimed to elucidate its role in endothelial biology. Cord blood-derived ECFCs were subjected to siRNA-mediated silencing of KLRK1-AS1, followed by blinded evaluations of monolayer morphology, barrier stability using ECIS impedance measurements, assessments of proliferation, and spheroid-based angiogenic activity. SiRNA-mediated silencing of KLRK1-AS1 induced detectable alterations in ECFC monolayer morphology (p = 0.047), while proliferation remained unaffected. Notably, KLRK1-AS1 knockdown significantly compromised endothelial barrier integrity, resulting in a 44% reduction in impedance after 48 h (p < 0.001), suggesting weakened intercellular contacts. In contrast, loss of KLRK1-AS1 enhanced angiogenic behaviour, demonstrated by an increased number of sprouts (+62%, p = 0.031). Together, these findings indicate that KLRK1-AS1 supports a quiescent, stable endothelial phenotype, with intact barrier function, while its depletion shifts ECFCs toward a more angiogenic, activated state. Our results identify KLRK1-AS1 as a previously unrecognised regulator of endothelial function.