Hypoxia-induced responses by endothelial colony-forming cells are modulated by placental growth factor

BACKGROUND: Endothelial colony-forming cells (ECFCs), also termed late outgrowth endothelial cells, are a well-defined circulating endothelial progenitor cell type with an established role in vascular repair. ECFCs have clear potential for cell therapy to treat ischaemic disease, although the precise mechanism(s) underlying their response to hypoxia remains ill-defined. METHODS: In this study, we isolated ECFCs from umbilical cord blood and cultured them on collagen. We defined the response of ECFCs to 1% O(2) exposure at acute and chronic time points. RESULTS: In response to low oxygen, changes in ECFC cell shape, proliferation, size and cytoskeleton phenotype were detected. An increase in the number of senescent ECFCs also occurred as a result of long-term culture in 1% O(2). Low oxygen exposure altered ECFC migration and tube formation in Matrigel®. Increases in angiogenic factors secreted from ECFCs exposed to hypoxia were also detected, in particular, after treatment with placental growth factor (PlGF). Exposure of cells to agents that stabilise hypoxia-inducible factors such as dimethyloxalylglycine (DMOG) also increased PlGF levels. Conditioned medium from both hypoxia-treated and DMOG-treated cells inhibited ECFC tube formation. This effect was reversed by the addition of PlGF neutralising antibody to the conditioned medium, confirming the direct role of PlGF in this effect. CONCLUSIONS: This study deepens our understanding of the response of ECFCs to hypoxia and also identifies a novel and important role for PlGF in regulating the vasculogenic potential of ECFCs. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13287-016-0430-0) contains supplementary material, which is available to authorized users

Circulating adipokines are associated with pre-eclampsia in women with type 1 diabetes

AIMS/HYPOTHESIS: The incidence of pre-eclampsia, a multisystem disorder of pregnancy, is fourfold higher in type 1 diabetic than non-diabetic women; it is also increased in women with features of the metabolic syndrome and insulin resistance. In a prospective study of pregnant women with type 1 diabetes, we measured plasma levels of adipokines known to be associated with insulin resistance: leptin, fatty acid binding protein 4 (FABP4), adiponectin (total and high molecular weight [HMW]; also known as high molecular mass), retinol binding protein 4 (RBP4) and resistin and evaluated associations with the subsequent development of pre-eclampsia. METHODS: From an established prospective cohort of pregnant type 1 diabetic women, we studied 23 who developed pre-eclampsia and 24 who remained normotensive; for reference values we included 19 healthy non-diabetic normotensive pregnant women. Plasma adipokines were measured (by ELISA) in stored samples from three study visits (Visit 1 – Visit 3) at different gestational ages (mean ± SD): Visit 1, 12.4 ± 1.8 weeks; Visit 2, 21.7 ± 1.4 weeks; and Visit 3, 31.4 ± 1.5 weeks. All the women were free of microalbuminuria and hypertension at enrolment. All study visits preceded the clinical onset of pre-eclampsia. RESULTS: In all groups, leptin, the ratio of leptin to total or HMW adiponectin, FABP4 concentration, ratio of FABP4 to total or HMW adiponectin and resistin level increased, while total and HMW adiponectin decreased, with gestational age. At Visit 1, (1) in diabetic women with vs without subsequent pre-eclampsia, leptin, ratio of leptin to total or HMW adiponectin, and ratio of FABP4 to total or HMW adiponectin, were increased (p<0.05), while total adiponectin was decreased (p<0.05); and (2) in normotensive diabetic vs non-diabetic women, total adiponectin was elevated (p<0.05). At Visits 2 and 3, (1) the primary findings in the two diabetic groups persisted, and FABP4 also increased in women with subsequent pre-eclampsia (p<0.05); and (2) there were no differences between the two normotensive groups. By logistic regression analyses after covariate adjustment (HbA(1c), insulin kg(−1) day(−1) and gestational age), the best predictive models for pre-eclampsia were as follows: Visit 1, doubling of leptin, OR 9.0 (p<0.01); Visit 2, doubling of the leptin:total adiponectin ratio, OR 3.7 (p<0.05); and Visit 3, doubling of FABP4 concentration, OR 25.1 (p<0.01). The associations were independent of BMI. CONCLUSIONS/INTERPRETATION: As early as the first trimester in type 1 diabetic women, adipokine profiles that suggest insulin resistance are associated with subsequent pre-eclampsia, possibly reflecting maternal characteristics that precede pregnancy. These associations persist in the second and third trimesters, and are independent of BMI. Insulin resistance may predispose women with type 1 diabetes to pre-eclampsia

Nox2 NADPH Oxidase Promotes Pathologic Cardiac Remodeling Associated with Doxorubicin Chemotherapy

Doxorubicin is a highly effective cancer treatment whose use is severely limited by dose-dependent cardiotoxicity. It is well established that doxorubicin increases reactive oxygen species (ROS) production. In this study, we investigated contributions to doxorubicin cardiotoxicity from Nox2 NADPH oxidase, an important ROS source in cardiac cells, which is known to modulate several key processes underlying the myocardial response to injury. Nox2-deficient mice (Nox2(−/−)) and wild-type (WT) controls were injected with doxorubicin (12 mg/kg) or vehicle and studied 8 weeks later. Echocardiography indicated that doxorubicin-induced contractile dysfunction was attenuated in Nox2(−/−) versus WT mice (fractional shortening: 29.5±1.4 vs 25.7±1.0 %; P<0.05). Similarly, in vivo pressure-volume analysis revealed that systolic and diastolic function was preserved in doxorubicin-treated Nox2(−/−) versus WT mice (ejection fraction: 52.6±2.5 vs 28.5±2.3 %, LVdPdt(min): −8379±416 vs −5198±527 mmHg s(−1), EDPVR: 0.051±0.009 vs 0.114±0.012; P<0.001). Furthermore, in response to doxorubicin, Nox2(−/−) mice exhibited less myocardial atrophy, cardiomyocyte apoptosis and interstitial fibrosis, together with reduced increases in profibrotic gene expression (procollagen IIIαI, TGF-β(3), connective tissue growth factor) and matrix metalloproteinase-9 activity, versus WT controls. These alterations were associated with beneficial changes in NADPH oxidase activity, oxidative/nitrosative stress and inflammatory cell infiltration. We found that adverse effects of doxorubicin were attenuated by acute or chronic treatment with the AT1 receptor antagonist, losartan, which is commonly used to reduce blood pressure. Our findings suggest that ROS specifically-derived from Nox2 NADPH oxidase make a substantial contribution to several key processes underlying development of cardiac contractile dysfunction and remodeling associated with doxorubicin chemotherapy

Response to Comment on Kelly et al. Subclinical First Trimester Renal Abnormalities Are Associated With Preeclampsia in Normoalbuminuric Women With Type 1 Diabetes. Diabetes Care 2018;41:120-127

OBJECTIVE This study was conducted to determine the utility of tubular (urinary/plasma neutrophil gelatinase-associated lipocalin [NGAL] and urinary kidney injury molecule 1 [KIM-1]) and glomerular (estimated glomerular filtration rate [eGFR]) biomarkers in predicting preeclampsia (PE) in pregnant women with type 1 diabetes mellitus (T1DM) who were free of microalbuminuria and hypertension at the first trimester. RESEARCH DESIGN AND METHODS This was a prospective study of T1DM pregnancy. Maternal urinary and plasma NGAL, urinary KIM-1 (ELISA of frozen samples), and eGFR (Chronic Kidney Disease Epidemiology Collaboration equation) were determined at three study visits (V1: 12.4 ± 1.8; V2: 21.7 ± 1.4; V3: 31.4 ± 1.5 weeks’ gestation [mean ± SD]) in 23 women with T1DM with subsequent PE (DM+PE+), 24 who remained normotensive (DM+PE−), and, for reference, in 19 normotensive pregnant women without diabetes (DM−). The groups with diabetes were matched for age, diabetes duration, and parity. All subjects were normotensive and free of microalbuminuria or albuminuria at V1. All study visits preceded the onset of PE. RESULTS Urinary creatinine-corrected NGAL (uNGALcc, ng/mg) was significantly elevated at V1 in DM+PE+ vs. DM+PE− women (P = 0.01); this remained significant after exclusion of leukocyte-positive samples (5 DM+PE+ and 2 DM+PE−) (P = 0.02). Accounting for BMI, HbA1c, and total daily insulin dose, a doubling of uNGALcc at V1 conferred a sevenfold increase in risk for PE (P = 0.026). In contrast, neither plasma NGAL nor urinary KIM-1 predicted PE. Also at V1, eGFR was elevated in DM+PE+ vs. DM+PE− (P = 0.04). CONCLUSIONS Early tubular and glomerular dysfunction may predict PE in first trimester women with T1DM, even if free of microalbuminuria. These data suggest that subclinical renal tubular and glomerular injury, if present early in pregnancy, may predispose women with T1DM to PE. </jats:sec