Preeclampsia (PE) is a common syndrome of pregnancy, characterized by new-onset hypertension and ... more Preeclampsia (PE) is a common syndrome of pregnancy, characterized by new-onset hypertension and proteinuria after gestational week 20, or new onset of hypertension and significant end-organ dysfunction. In the worst cases, it can threaten the survival of both mother and baby. Extracellular vesicles (EVs) are lipid-bilayer nanoparticles released from cells. They are involved in cell-cell communication and transport of diverse cargo molecules. Small extracellular vesicles (sEVs, exosomes) are defined by their size and biogenesis within the endocytic compartment of the cell or reverse budding of the plasma membrane. The function of circulating gestational EVs, released from maternal organs or the placenta, remains to be explored. Here, we focused on sEVs that circulate in the maternal blood in the third trimester of human pregnancy and hypothesized that sEVs from pregnant women with PE play a role in regulation of vessel tone. When compared to sEVs from women with uncomplicated pregnancies, ex vivo exposure of isolated mouse mesenteric arteries to sEVs purified from the plasma of pregnant women with PE led to constriction in response to intraluminal pressure. This effect was not observed using microvesicles from the plasma of women with PE or using PE plasma that was depleted of EVs. Blood vessels exposed to sEVs from women with PE were also more resistant to methacholine-stimulated relaxation. Immunofluorescence microscopy confirmed the presence of sEVs within the vessel wall. Together, these data support the notion that circulating sEVs from pregnant women play a role in the regulation of arterial tone.
ABSTRACT Lead remains one of the most significant occupational and environmental hazards world-wi... more ABSTRACT Lead remains one of the most significant occupational and environmental hazards world-wide, despite major efforts to ban its use in gasoline and paints. While environmental exposures have generally fallen in countries such as Canada and the US, occupational exposures remain significant. Workers are exposed in major industries, such as mining, battery manufacture, and electronics; environmental exposures result from emissions to air from stationary sources such as smelters and incinerators, contamination of drinking water from lead plumbing, contact with lead based paint, and leaching of lead from ceramics and glassware. Over the past 10 years, many countries have adopted public health guidance to prevent lead poisoning in children, using current epidemiological and toxicological information to set a blood lead level of 10 mcg/dL as an indicator of potentially toxic exposures. However, occupational guidelines and standards adopted to prevent adult lead toxicity have not been changed for over 20 years. In most developed countries, occupational exposures are set to prevent blood lead elevations above 40 or 50 mcg/dL. These exposures are clearly unsafe since effects on neurological, renal, and nervous system functions have been documented in adults with these levels of lead in blood (WHO, 1990)
Introduction: Maternal vascular malperfusion (MVM) lesions in the placenta are characterized by i... more Introduction: Maternal vascular malperfusion (MVM) lesions in the placenta are characterized by incomplete vascular remodeling and vessel features similar to atherosclerosis. MVM lesions indicate a maladaptive maternal vascular response to pregnancy, are often detected in hypertensive disorders of pregnancy (HDP), and may provide a pathologic link to future cardiovascular disease. The endothelial glycocalyx is a glycoprotein-rich layer that is critical for microvascular health and damage may have an important role in the pathophysiology of microcardiovascular disease risk. Hypothesis: We hypothesized that women with malperfusion lesions of the placenta are more likely to evidence microvascular glycocalyx derangement a decade after delivery compared to women without these lesions and that this effect would be most pronounced among women with a history of HDP. Methods: A total of 412 women with placental pathology (N=129 with MVM lesions, N=283 without MVM lesions) were evaluated at 8-10 years postpartum. Placental specimens were reviewed by a blinded perinatal pathologist . HDP (including preeclampsia and gestational hypertension) were abstracted from the medical record. Glycocalyx barrier function was assessed using sublingual sidestream dark field imaging, with reduction defined as deeper penetration of red blood cells (RBCs) into the glycocalyx of the sublingual microcirculation (5-25μm diameter). We compared the median diameter (size) of microvessels, penetration of RBCs into the glycocalyx (perfused boundary region, PBR) and microvascular density (total length of perfused microvessels/mm 2 surface area) in women with and without MVM lesions. Results: Women with placental MVM lesions had smaller-sized sublingual vessels (median 8.59 μM [IQR 8.12, 9.19] vs. 9.01 μM [IQR 8.37, 9.64]; p<0.001), and a lower density of vessels compared to women without lesions. Glycocalyx perfused boundary region was unexpectedly lower in women with MVM lesions (median 2.20 μM [IQR 2.06, 2.43] vs. 2.32 μM [IQR 2.15, 2.50]; p=0.003) in 10-19 μM vessels. Women with HDP and MVM lesions appear to be the most impacted, with the smallest size vessels (median 8.47 [IQR 8.09-9.13]) and the lowest glycocalyx PBR across all vessel sizes. Women with MVM lesions without a HDP similarly had evidence of microvascular glycocalyx derangement whereas women with HDP without placental lesions had a glycocalyx profile similar to women without MVM or a history of HDP. Conclusions: A decade after delivery, women with a history of placental malperfusion lesions had alterations in microvascular perfusion. Women with MVM lesions and a history of HDP appear to be the most severely impacted, which may reflect an underlying maladaptive vascular phenotype detected in the placenta at the time of pregnancy that might provide pathologic insight into future maternal microvascular health.
American Journal of Physiology-cell Physiology, Mar 1, 2022
The small conductance calcium-activated potassium channel (KCa2.3) has long been recognized for i... more The small conductance calcium-activated potassium channel (KCa2.3) has long been recognized for its role in mediating vasorelaxation through the endothelium-derived hyperpolarization (EDH) response. Histone deacetylases (HDACs) have been implicated as potential modulators of blood pressure and histone deacetylase inhibitors (HDACi) are being explored as therapeutics for hypertension. Herein, we show that HDACi increase KCa2.3 expression when heterologously expressed in HEK cells and endogenously expressed in primary cultures of human umbilical vein endothelial cells (HUVECs) and human intestinal microvascular endothelial cells (HIMECs). When primary endothelial cells were exposed to HDACi, KCa2.3 transcripts, subunits, and functional current are increased. Quantitative RT-PCR (qPCR) demonstrated increased KCa2.3 mRNA following HDACi, confirming transcriptional regulation of KCa2.3 by HDACs. By using pharmacological agents selective for different classes of HDACs, we discriminated between cytoplasmic and epigenetic modulation of KCa2.3. Biochemical analysis revealed an association between the cytoplasmic HDAC6 and KCa2.3 in immunoprecipitation studies. Specifically inhibiting HDAC6 increases expression of KCa2.3. In addition to increasing the expression of KCa2.3, we show that nonspecific inhibition of HDACs causes an increase in the expression of the molecular chaperone Hsp70 in endothelial cells. When Hsp70 is inhibited in the presence of HDACi, the magnitude of the increase in KCa2.3 expression is diminished. Finally, we show a slower rate of endocytosis of KCa2.3 as a result of exposure of primary endothelial cells to HDACi. These data provide the first demonstrated approach to increase KCa2.3 channel number in endothelial cells and may partially account for the mechanism by which HDACi induce vasorelaxation.
Introduction: Maternal vascular malperfusion (MVM) lesions in the placenta are commonly found in ... more Introduction: Maternal vascular malperfusion (MVM) lesions in the placenta are commonly found in women with adverse pregnancy outcomes associated with increased CVD in later life. Minimal criteria for MVM include vasculopathy, accelerated villous maturation and increased syncytial knots, and villous infarction upon pathologic examination; expanded definitions have included presence of fibrin deposition (intervillous or perivillous) or low placental weight (<10 th %). Hypothesis: Women with a history of MVM lesions would have evidence of cardiometabolic risk factors and peripheral microvascular changes a decade after delivery independent of pregnancy outcome. Methods: A total of 469 women with placental pathology data available were evaluated at 8-10 years postpartum. Placental specimens were reviewed by a perinatal pathologist. Cardiometabolic variables were measured at the time of the study visit. Sidestream dark field imaging was used to assess the sublingual microcirculation. We compared the median size (diameter) of microvessels, density (total length of perfused microvessels/mm 2 ) and penetration of red cells into the glycocalyx of vessels 5-25μm diameter (perfused boundary region, PBR) in women 8-10 years after pregnancy, using the minimal MVM criteria (compared to none). Expanded criteria were examined alone. Significance =*p<0.05 vs no MVM lesions. Results: Women with minimally defined MVM lesions in their placentas had higher diastolic blood pressure (79mmHg MVM vs. 75 mmHg No MVM*), LDL (111mg/dL MVM vs. 101 mg/dL No MVM*), Cholesterol (185 mg/dL MVM vs. 175mg/dL No MVM*) and insulin (14mg/dL MVM vs. 12mg/dL No MVM*), along with smaller-sized microvessels (median 8.75±1.1 μM vs. 9.06±0.7 μM*), and a lower density of perfused microvessels compared to women without MVM lesions (3590±1260mm/mm 2 MVM vs. 3970±820 mm/mm 2 No MVM*) a decade after delivery. Glycocalyx PBR was smaller in women with prior MVM vs. women without lesions (2.01±0.23μm vs. 2.09±0.15μm, P=0.02). Similar results were not seen in subjects with either presence of fibrin or small placenta in the absence of other MVM criteria. Discussion: Using minimal criteria MVM was associated most strongly with maternal cardiometabolic and microvascular differences a decade later.
Introduction: Gestational diabetes mellitus (GDM) increases risk for cardiovascular disease (CVD)... more Introduction: Gestational diabetes mellitus (GDM) increases risk for cardiovascular disease (CVD). The subclinical cardiovascular structural and functional changes that contribute to long-term cardiovascular risk are unclear. Hypothesis: We hypothesized that GDM is associated with adverse cardiovascular remodeling, diastolic function abnormalities, and endothelial dysfunction at approximately a decade after delivery, thereby increasing CVD risk. Methods: We conducted a cross-sectional analysis of women from an existing cohort with abstracted clinical pregnancy data. Women attended a follow-up visit at a median of 9 years after delivery. Echocardiograms, Peripheral Arterial Tonometry (EndoPAT), glycocalyx analysis (GlycoCheck) and laboratory testing were conducted at the follow-up visit. Results: Among 217 women who attended the follow-up visit, 53 (24%) had history of GDM. After adjusting for age, race, preeclampsia history or preterm delivery, women with prior Compared to women without GDM, women with prior GDM had higher interventricular septal and left ventricular (LV) posterior wall thickness and lower septal e’ velocity ( Table ; Model 2). They also had worse endothelial function with lower reactive hyperemia index (RHI) and adverse GlycoCheck parameters. Measures of hypertrophy were attenuated by additional adjustment for body mass index, hypertension, and diabetes (Model 3), but findings of adverse LV diastology, RHI and GlycoCheck parameters remained significant. Conclusions: Women with GDM were more likely to have increased LV wall thickness, adverse diastology and endothelial dysfunction nearly a decade postpartum. Adjusting for traditional cardiovascular risk factors attenuated some but not all parameters. These findings suggest that subclinical structural and functional cardiac and vascular changes may be a mechanism by which GDM causes increased risk of CVD.
Preeclampsia (PE) is a common syndrome of pregnancy, characterized by new-onset hypertension and ... more Preeclampsia (PE) is a common syndrome of pregnancy, characterized by new-onset hypertension and proteinuria after gestational week 20, or new onset of hypertension and significant end-organ dysfunction. In the worst cases, it can threaten the survival of both mother and baby. Extracellular vesicles (EVs) are lipid-bilayer nanoparticles released from cells. They are involved in cell-cell communication and transport of diverse cargo molecules. Small extracellular vesicles (sEVs, exosomes) are defined by their size and biogenesis within the endocytic compartment of the cell or reverse budding of the plasma membrane. The function of circulating gestational EVs, released from maternal organs or the placenta, remains to be explored. Here, we focused on sEVs that circulate in the maternal blood in the third trimester of human pregnancy and hypothesized that sEVs from pregnant women with PE play a role in regulation of vessel tone. When compared to sEVs from women with uncomplicated pregnancies, ex vivo exposure of isolated mouse mesenteric arteries to sEVs purified from the plasma of pregnant women with PE led to constriction in response to intraluminal pressure. This effect was not observed using microvesicles from the plasma of women with PE or using PE plasma that was depleted of EVs. Blood vessels exposed to sEVs from women with PE were also more resistant to methacholine-stimulated relaxation. Immunofluorescence microscopy confirmed the presence of sEVs within the vessel wall. Together, these data support the notion that circulating sEVs from pregnant women play a role in the regulation of arterial tone.
ABSTRACT Lead remains one of the most significant occupational and environmental hazards world-wi... more ABSTRACT Lead remains one of the most significant occupational and environmental hazards world-wide, despite major efforts to ban its use in gasoline and paints. While environmental exposures have generally fallen in countries such as Canada and the US, occupational exposures remain significant. Workers are exposed in major industries, such as mining, battery manufacture, and electronics; environmental exposures result from emissions to air from stationary sources such as smelters and incinerators, contamination of drinking water from lead plumbing, contact with lead based paint, and leaching of lead from ceramics and glassware. Over the past 10 years, many countries have adopted public health guidance to prevent lead poisoning in children, using current epidemiological and toxicological information to set a blood lead level of 10 mcg/dL as an indicator of potentially toxic exposures. However, occupational guidelines and standards adopted to prevent adult lead toxicity have not been changed for over 20 years. In most developed countries, occupational exposures are set to prevent blood lead elevations above 40 or 50 mcg/dL. These exposures are clearly unsafe since effects on neurological, renal, and nervous system functions have been documented in adults with these levels of lead in blood (WHO, 1990)
Introduction: Maternal vascular malperfusion (MVM) lesions in the placenta are characterized by i... more Introduction: Maternal vascular malperfusion (MVM) lesions in the placenta are characterized by incomplete vascular remodeling and vessel features similar to atherosclerosis. MVM lesions indicate a maladaptive maternal vascular response to pregnancy, are often detected in hypertensive disorders of pregnancy (HDP), and may provide a pathologic link to future cardiovascular disease. The endothelial glycocalyx is a glycoprotein-rich layer that is critical for microvascular health and damage may have an important role in the pathophysiology of microcardiovascular disease risk. Hypothesis: We hypothesized that women with malperfusion lesions of the placenta are more likely to evidence microvascular glycocalyx derangement a decade after delivery compared to women without these lesions and that this effect would be most pronounced among women with a history of HDP. Methods: A total of 412 women with placental pathology (N=129 with MVM lesions, N=283 without MVM lesions) were evaluated at 8-10 years postpartum. Placental specimens were reviewed by a blinded perinatal pathologist . HDP (including preeclampsia and gestational hypertension) were abstracted from the medical record. Glycocalyx barrier function was assessed using sublingual sidestream dark field imaging, with reduction defined as deeper penetration of red blood cells (RBCs) into the glycocalyx of the sublingual microcirculation (5-25μm diameter). We compared the median diameter (size) of microvessels, penetration of RBCs into the glycocalyx (perfused boundary region, PBR) and microvascular density (total length of perfused microvessels/mm 2 surface area) in women with and without MVM lesions. Results: Women with placental MVM lesions had smaller-sized sublingual vessels (median 8.59 μM [IQR 8.12, 9.19] vs. 9.01 μM [IQR 8.37, 9.64]; p<0.001), and a lower density of vessels compared to women without lesions. Glycocalyx perfused boundary region was unexpectedly lower in women with MVM lesions (median 2.20 μM [IQR 2.06, 2.43] vs. 2.32 μM [IQR 2.15, 2.50]; p=0.003) in 10-19 μM vessels. Women with HDP and MVM lesions appear to be the most impacted, with the smallest size vessels (median 8.47 [IQR 8.09-9.13]) and the lowest glycocalyx PBR across all vessel sizes. Women with MVM lesions without a HDP similarly had evidence of microvascular glycocalyx derangement whereas women with HDP without placental lesions had a glycocalyx profile similar to women without MVM or a history of HDP. Conclusions: A decade after delivery, women with a history of placental malperfusion lesions had alterations in microvascular perfusion. Women with MVM lesions and a history of HDP appear to be the most severely impacted, which may reflect an underlying maladaptive vascular phenotype detected in the placenta at the time of pregnancy that might provide pathologic insight into future maternal microvascular health.
American Journal of Physiology-cell Physiology, Mar 1, 2022
The small conductance calcium-activated potassium channel (KCa2.3) has long been recognized for i... more The small conductance calcium-activated potassium channel (KCa2.3) has long been recognized for its role in mediating vasorelaxation through the endothelium-derived hyperpolarization (EDH) response. Histone deacetylases (HDACs) have been implicated as potential modulators of blood pressure and histone deacetylase inhibitors (HDACi) are being explored as therapeutics for hypertension. Herein, we show that HDACi increase KCa2.3 expression when heterologously expressed in HEK cells and endogenously expressed in primary cultures of human umbilical vein endothelial cells (HUVECs) and human intestinal microvascular endothelial cells (HIMECs). When primary endothelial cells were exposed to HDACi, KCa2.3 transcripts, subunits, and functional current are increased. Quantitative RT-PCR (qPCR) demonstrated increased KCa2.3 mRNA following HDACi, confirming transcriptional regulation of KCa2.3 by HDACs. By using pharmacological agents selective for different classes of HDACs, we discriminated between cytoplasmic and epigenetic modulation of KCa2.3. Biochemical analysis revealed an association between the cytoplasmic HDAC6 and KCa2.3 in immunoprecipitation studies. Specifically inhibiting HDAC6 increases expression of KCa2.3. In addition to increasing the expression of KCa2.3, we show that nonspecific inhibition of HDACs causes an increase in the expression of the molecular chaperone Hsp70 in endothelial cells. When Hsp70 is inhibited in the presence of HDACi, the magnitude of the increase in KCa2.3 expression is diminished. Finally, we show a slower rate of endocytosis of KCa2.3 as a result of exposure of primary endothelial cells to HDACi. These data provide the first demonstrated approach to increase KCa2.3 channel number in endothelial cells and may partially account for the mechanism by which HDACi induce vasorelaxation.
Introduction: Maternal vascular malperfusion (MVM) lesions in the placenta are commonly found in ... more Introduction: Maternal vascular malperfusion (MVM) lesions in the placenta are commonly found in women with adverse pregnancy outcomes associated with increased CVD in later life. Minimal criteria for MVM include vasculopathy, accelerated villous maturation and increased syncytial knots, and villous infarction upon pathologic examination; expanded definitions have included presence of fibrin deposition (intervillous or perivillous) or low placental weight (<10 th %). Hypothesis: Women with a history of MVM lesions would have evidence of cardiometabolic risk factors and peripheral microvascular changes a decade after delivery independent of pregnancy outcome. Methods: A total of 469 women with placental pathology data available were evaluated at 8-10 years postpartum. Placental specimens were reviewed by a perinatal pathologist. Cardiometabolic variables were measured at the time of the study visit. Sidestream dark field imaging was used to assess the sublingual microcirculation. We compared the median size (diameter) of microvessels, density (total length of perfused microvessels/mm 2 ) and penetration of red cells into the glycocalyx of vessels 5-25μm diameter (perfused boundary region, PBR) in women 8-10 years after pregnancy, using the minimal MVM criteria (compared to none). Expanded criteria were examined alone. Significance =*p<0.05 vs no MVM lesions. Results: Women with minimally defined MVM lesions in their placentas had higher diastolic blood pressure (79mmHg MVM vs. 75 mmHg No MVM*), LDL (111mg/dL MVM vs. 101 mg/dL No MVM*), Cholesterol (185 mg/dL MVM vs. 175mg/dL No MVM*) and insulin (14mg/dL MVM vs. 12mg/dL No MVM*), along with smaller-sized microvessels (median 8.75±1.1 μM vs. 9.06±0.7 μM*), and a lower density of perfused microvessels compared to women without MVM lesions (3590±1260mm/mm 2 MVM vs. 3970±820 mm/mm 2 No MVM*) a decade after delivery. Glycocalyx PBR was smaller in women with prior MVM vs. women without lesions (2.01±0.23μm vs. 2.09±0.15μm, P=0.02). Similar results were not seen in subjects with either presence of fibrin or small placenta in the absence of other MVM criteria. Discussion: Using minimal criteria MVM was associated most strongly with maternal cardiometabolic and microvascular differences a decade later.
Introduction: Gestational diabetes mellitus (GDM) increases risk for cardiovascular disease (CVD)... more Introduction: Gestational diabetes mellitus (GDM) increases risk for cardiovascular disease (CVD). The subclinical cardiovascular structural and functional changes that contribute to long-term cardiovascular risk are unclear. Hypothesis: We hypothesized that GDM is associated with adverse cardiovascular remodeling, diastolic function abnormalities, and endothelial dysfunction at approximately a decade after delivery, thereby increasing CVD risk. Methods: We conducted a cross-sectional analysis of women from an existing cohort with abstracted clinical pregnancy data. Women attended a follow-up visit at a median of 9 years after delivery. Echocardiograms, Peripheral Arterial Tonometry (EndoPAT), glycocalyx analysis (GlycoCheck) and laboratory testing were conducted at the follow-up visit. Results: Among 217 women who attended the follow-up visit, 53 (24%) had history of GDM. After adjusting for age, race, preeclampsia history or preterm delivery, women with prior Compared to women without GDM, women with prior GDM had higher interventricular septal and left ventricular (LV) posterior wall thickness and lower septal e’ velocity ( Table ; Model 2). They also had worse endothelial function with lower reactive hyperemia index (RHI) and adverse GlycoCheck parameters. Measures of hypertrophy were attenuated by additional adjustment for body mass index, hypertension, and diabetes (Model 3), but findings of adverse LV diastology, RHI and GlycoCheck parameters remained significant. Conclusions: Women with GDM were more likely to have increased LV wall thickness, adverse diastology and endothelial dysfunction nearly a decade postpartum. Adjusting for traditional cardiovascular risk factors attenuated some but not all parameters. These findings suggest that subclinical structural and functional cardiac and vascular changes may be a mechanism by which GDM causes increased risk of CVD.
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