bluuebunny/crossref_metadata_2025 huggingface dataset:
Local Angiotensin 1–7 Administration Augments Microvascular Endothelial Function in Women Who Have Had Preeclampsia
Authors: Stanhewicz Anna , Alexander Lacy
Published: June 2021

Women with a history of preeclampsia are at increased risk of developing cardiovascular disease. Despite remission of the clinical symptoms of preeclampsia postpartum, women who have had preeclampsia demonstrate microvascular endothelial dysfunction, mediated in part by increased sensitivity to angiotensin II. Angiotensin 1–7 (ang 1–7) is an endogenous inhibitor of the actions of angiotensin II and therefore a biologically plausible target for improving endothelial function in postpartum women who have had preeclampsia. Using the cutaneous microcirculation as a model, we hypothesized that women who have had preeclampsia (PreEC) would have attenuated endothelium‐dependent‐ and reduced nitric oxide (NO)‐dependent vasodilation compared to control women who had a normal pregnancy (HC). We further hypothesized that localized ang 1–7 administration would increase endothelium‐dependent vasodilation and NO‐dependent vasodilation in PreEC, but not HC. The subject sample included 8 PreEC (26±2 yrs of age; 6±2 months post‐partum) and 7 HC (32±2 yrs; 6±1 months post‐partum). Four intradermal microdialysis fibers were placed in the skin of the ventral forearm for the graded infusion of acetylcholine (ACh, 10−7 – 102 mM), ACh + 15 mM NG Nitro‐L‐arginine methyl ester (L‐NAME; nitric oxide synthase antagonist), ACh + 100μM ang 1–7, or ACh + 15 mM L‐NAME + 100μM ang 1–7. Red cell flux was measured over each site by laser‐Doppler flowmetry (LDF). Cutaneous vascular conductance was calculated (CVC=LDF/MAP) and normalized to the respective site‐specific maximum (%CVCmax; 28 mM SNP + local heating to 43°C). ACh‐induced vasodilation was attenuated in PreEC compared to HC (logEC50: −1.0±0.2 vs. −1.8±0.1; p=0.04). There was no difference between PreEC and HC when ACh was co‐infused with L‐NAME (PreEC logEC50: −0.9±0.3 vs. HC: −1.2±0.2 logEC50). ACh + Ang 1–7 co‐infusion augmented the vasodilation response in PreEC (logEC50: −1.9±0.1) compared to ACh alone (logEC50: −1.0±0.2) (p<0.001) but had no effect in HC. Co‐infusion of ang1–7 + L‐NAME + ACh did not differ from ACh + L‐NAME in either group. Women who have had preeclampsia demonstrate attenuated endothelium‐dependent and NO‐dependent vasodilation compared to women who have had a healthy pregnancy. Ang 1–7 increased endothelium‐dependent vasodilation via NOS‐mediated pathways in women who have had preeclampsia, suggesting that ang 1–7 may be a viable therapeutic target for improved microvascular endothelial function in women who have had a preeclamptic pregnancy.

Support or Funding Information

NIH F32 HL129677‐03 (Stanhewicz), R01 HL093238‐07 (Alexander)

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Protective Effects of Diet and Sex on Cell Death and Intracellular Calcium in Resistance Arteries during Oxidative Stress
Authors: Norton Charles E. , Sinkler Shenghua Y. , Manrique Camila M. , Segal Steven S.
Published: June 2021

Reactive oxygen species are implicated in vascular dysfunction and the development of cardiovascular disease. However, chronic exposure to oxidative stress during advanced age protects endothelial cells (ECs) of the superior epigastric artery (SEA) in male mice from hydrogen peroxide (H2O2)‐induced Ca2+ entry and cell death (PMC4422569), and we have found similar protection in SEA smooth muscle cells (SMCs). We hypothesized that a Western style diet (WD) high in fat and fructose, by promoting chronic oxidative stress, would also improve vascular cell survival during exposure to H2O2. Because females appear more resilient to oxidative stress compared to males, we also investigated the effect of sex on cell death and intracellular calcium ([Ca2+]i) with WD. Male and female C57BL/6 mice (age, 4 weeks; n=4–5/group) were fed WD (TestDiet 58Y1; calories: 46% fat, 17.5% sucrose, 17.5% high fructose corn syrup; 19% protein), or Standard diet (Formulab Diet 5008; calories: 17% Fat, 56% carbohydrate, 27% protein) for 20 weeks. A mouse was then anesthetized (isoflurane) and the SEA (inner diameter, 100–150 μm) was isolated, pressurized to 100 cm H2O in physiological salt solution (pH 7.4, 37°C), and exposed to H2O2 (200 μM) for 50 minutes. Hoechst 33342 (1 μM) stained nuclei of all cells while propidium iodide (2 μM) stained nuclei from dead cells; SMC nuclei (n=121±3 per SEA) were oriented perpendicular to the vessel axis and EC nuclei (n=125±2 per SEA) were oriented parallel to the vessel axis. With Standard diet, SEAs from males had greater (P<0.05) cell death (SMCs=21±1%, ECs=6±1%) versus SEAs from females (SMCs=9±2%, ECs=2%). Consuming WD attenuated SMC death in SEAs from both males (to 11±6%) and females (to 3±1%) (P<0.05 for each) as well as in ECs from males (to 2%) with no further effect in ECs from females (2%). Because an aberrant rise in [Ca2+]i can initiate cell death, [Ca2+]i responses to H2O2 were evaluated using Fura‐2 fluorescence (F340/F380 ratios). With no effect of diet or sex on [Ca2+]i at rest, H2O2 increased [Ca2+]i in SEAs from males fed Standard diet (ΔF340/F380=0.57±0.04) by an 8‐fold greater (P<0.05) extent than in SEAs from females (ΔF340/F380=0.07±0.05). SEAs of males fed a WD exhibited a reduced [Ca2+]i response to H2O2 (ΔF340/F380=0.45±0.08) (P<0.05), however this effect of diet was not observed in SEAs of females (ΔF340/F380=0.19±0.06). We conclude that ECs and SMCs in resistance arteries of females are more resilient to acute H2O2 exposure compared to males and that WD promotes resilience to oxidative stress most effectively in males.

Support or Funding Information

NIH R37HL041026; 5K08HL129074

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Roles of Cell‐Cell Junction and Substrate Stiffness in Determining 3D Forces of Endothelial Cells
Authors: Hur Sung Sik , Yeh Yi‐Ting , Lee Kyunghang , Wang Yuanjia , Li Yi‐Shuan , Chien Shu
Published: June 2021

Mechanical forces play an important role in regulating structure and functions of cells, including motility, proliferation, and survival. The integrity of cell‐cell junction is crucial in the physiological behavior of endothelial cells. Thus, it is essential to understand the modulation of endothelial cells by their micro‐environment such as substrate stiffness, confluency, and cell‐cell junction.

We have developed three‐dimensional traction force microscopy (3D‐TFM) and intracellular force microscopy (3D‐IFM) to measure cell‐ECM, cell‐cell, and intracellular stresses of live cells in three dimensions at the subcellular level. These novel methods have been applied in order to investigate the mechanical responses of endothelial cells to changes in substrate stiffness, cell confluency, and cell‐cell junction. The results indicate that endothelial cells exhibit differences in the magnitude and spatial distribution of mechanical behaviors (traction and intracellular stress) and morphological features (area and aspect ratio) in response to substrate stiffness (1.5 kPa and 10b kPa hydrogel), cell confluency (existence of cell‐cell junction), and junction‐affecting drugs (thrombin and angiopoietin).

We have shown that biophysical and biochemical environments are important in the control of endothelial cell structure and function. Studying how the forces are regulated spatially and temporally at the subcellular level in response to changes of cellular microenvironment can lead to further understanding of the physiology of endothelial cells and pathogenesis of vascular diseases.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Estrogen receptor alpha mediated activation of the endothelial epithelial sodium channel: role in the genesis of arterial stiffness
Authors: Manrique Camila , Yang Yan , Lising Alexander , Chen Dongqing , Aroor Annayya , Sowers James R. , Hill Michael
Published: June 2021

Premature arterial stiffening is often seen in obesity and type 2 diabetes (T2D). Although both men and women are affected, T2D women are at greater risk. As augmented arterial stiffness is an independent predictor of cardiovascular disease, the increased susceptibility of women to arterial stiffening may explain their higher overall risk. In healthy females, estrogen signaling prevents stiffening, but these effects are blunted in obesity where signaling via estrogen receptor alpha (ERα) appears deleterious. We have previously reported that deletion of ERα in endothelial cells (EC) results in decreased arterial stiffening in conditions of over‐nutrition and insulin resistance. Importantly, the EC epithelial sodium channel (ENaC) has been hypothesized as a central mediator in the genesis of endothelial dysfunction and arterial stiffness, and estrogen has been shown to activate ENaC activation. Here we examine the preferential activation of the EC ENaC in females under conditions of insulin resistance and the role of estrogen signaling, specifically via ERα, on the activation of the EC ENaC. In the present investigation we report that cultured aortic EC from female mice exhibited a significant increase in amiloride‐sensitive sodium currents (ENaC currents) assessed by patch‐clamp after treatment with 100 nM 17beta‐estradiol (E2) for 24 hours when compared to control. In contrast, there was no significant effect of E2 treatment on ENaC currents in EC from male mice. Further, we found that C57BL6/J female mice fed for 16 weeks with a diet high in fat and high in fructose (WD; TestDiet 58Y1; calories: 46% fat, 17.5% sucrose, 17.5% high fructose corn syrup; 19% protein) exhibit augmented aortic endothelial surface stiffness assessed via atomic force microscopy when compared with male mice. Moreover, primary lung ECs from female mice fed WD exhibited elevated E2‐stimulated ENaC currents when compared with control fed female mice and with male mice. In addition, in primary ECs isolated from female EC‐specific ERα knockout mice there was a significant abrogation of the E2‐stimulated amiloride sensitive sodium currents without significant changes in aldosterone (10 uM) induced sodium currents. Our results show that in conditions of over‐nutrition, there is enhanced EC ENaC activation and highlights the important role of estrogen, via ERa signaling, as a modulator of the expression and activity of the EC ENaC. Future studies will determine the direct impact of ERα‐mediated activation of ENaC in the genesis of arterial stiffness in obesity and T2D.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Arterial dysfunction displayed by old mice with repressed endothelial cell autophagy is rescued by pharmacological activation of purinergic 2Y1 receptors
Authors: Kwon Oh Sung , Cho Jae Min , Park Seul‐Ki , Bharath Leena Panneerseelan , Richardson Russell S. , Anandh Pon Velayutham Babu , Boudina Sihem , Symons J David
Published: June 2021

Earlier we reported that genetic repression of endothelial cell (EC) autophagy impairs autocrine signaling via the purinergic 2Y1 (P2Y1) receptor to EC nitric oxide (NO) synthase (eNOS), and prevents NO generation in response to shear stress. Herein we sought to determine whether aging‐associated endothelial dysfunction displayed by mice with defective vascular autophagy could be restored by promoting purinergic signaling. First, mRNA and protein expression of autophagy markers was lower in ECs and arterial homogenates of 22–23 month old (old) vs. 6–7 month old (adult) mice. Second, the ability of aged mice with repressed basal autophagy to upregulate this process in response to physiological stimuli was prevented. Specifically, 14 h fasting and 60‐min treadmill‐running increased autophagy in arteries from adult but not old mice. Third, autophagy suppression (3‐methyladenine) impaired flow‐mediated vasodilation in arteries from adult mice evaluated ex vivo, while autophagy activation (trichostatin‐A) preserved vasodilation in arteries from older animals. Finally, the selective P2Y1 receptor agonist 2‐methylthio‐ADP restored arterial function in arteries from aged mice whereas P2Y1 receptor inhibition using MRS2179 precipitated an aging phenotype in vessels from adult animals. We provide the first evidence that aging : (i) prevents the autophagic response to fasting and acute exercise and (ii) attenuates flow‐mediated vasodilation in a manner that can be restored by intervening distal to defective vascular autophagy i.e., by pharmacological promotion of purinergic autocrine signaling. Further research concerning the G protein‐coupled P2Y family of receptors is warranted in an effort to explore new therapeutic treatment options for aging‐related endothelial dysfunction that is secondary to defective EC autophagy.

Support or Funding Information

AHA 16GRNT31050004, NIH RO3AGO52848, Seed Grants from the UU Office of the Vice‐President for Research, the UU College of Health, the UU Center on Aging, the UU Diabetes and Metabolism Center, and the Diabetes Research Center at Washington University at Saint Louis 5 P30 DK020579 (JDS)

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Enhanced Blood Pressure Lowering Responsiveness with Endocrine‐Sympathoinhibitory Electroacupuncture in Middle‐Aged Hypertensive Women
Authors: Tjen‐A‐Looi Stephanie , Xie Lifang , Fu Liang‐Wu , Li Peng , Malik Shaista
Published: June 2021

Our recently published study shows that 8‐week electroacupuncture (EA) at P5–6 and ST36–37 reduces blood pressure (70% responsiveness, blood pressure decrease of ≥ −6 mmHg) and sympathetic activity in a group of male and female (38–75 year) patients with mild to moderate hypertension (HTN). They were off of antihypertensive medications. Blood pressure reduction with 30‐min EA once a week treatment was observed by week 4. After 8 weeks of EA sessions, the blood pressure reduction lasted for at least a month. Here we define treatment at P5–6+ST36–37 as the sympathoinhibitory EA. Interestingly, the majority (64%) of middle‐aged women with HTN were not responsive to this treatment that reduces sympathetic activity. To this end, we formulated a targeted treatment towards middle‐aged perimenopausal hypertensive women. We hypothesized that endocrine‐sympathoinhibitory EA treatment decreases blood pressure in majority of middle‐aged perimenopausal females with mild to moderate HTN. Eleven enrolled women ages 49 to 66 year with hypertension were randomly assigned to sympathoinhibitory EA treatment (P5–6+ST36–37, n=6) or endocrine‐sympathoinhibitory EA treatment (P6+LI4+ST36+Sp6+CV3–4+LR3+KI3, n=5). Participants were not on antihypertensive medications and hormonal therapy. The enrolled patients have completed the 8‐week course of treatment. The blood pressure lowering responsiveness (≥ −6 mmHg) to endocrine‐sympathoinhibitory EA was 80% while only 33% of the subjects treated with sympathoinhibitory EA lowered their blood pressures. Peak systolic blood pressure (SBP) during 24 hours dropped from 177±7.4 to 160±5.0 mmHg (P=0.033) while averaged 24‐hour SBP dropped from 144±3.3 to 134±2.5 mmHg (P=0.036) in 5 subjects treated with endocrine‐sympathoinhibitory EA. The peak mean blood pressure (MBP) tended to decrease with P value of 0.065 in 5 subjects. On the other hand, 8‐week course of sympathoinhibitory EA treatment did not decrease SBP, MBP, peak SBP and peak MAP in 6 subjects. Thus, endocrine‐sympathoinhibitory EA in middle‐aged hypertensive women may enhance blood pressure lowering responsiveness compared with sympathoinhibitory EA treatment.

Support or Funding Information

Adolf Coors Foundation

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
A Novel Role for Sox6 in Renin Expression Control During Renal Artery Stenosis Induced Hypertension
Authors: Gomez Jose A. , Saleem Mohammad , Xiao Liang , Horton Kandi D. , Hodgkinson Conrad P.
Published: June 2021

Study Objective

We wanted to determine if the transcription factor Sox6 played a role in renin expression control and in the hypertension induced by renal artery stenosis. In renal artery stenosis, renin is a key disease driver. Renin catalyzes the rate limiting step in the Renin Angiotensin Aldosterone System (RAAS); converting angiotensinogen to angiotensin I. We used a novel transgenic mouse (Ren1dCre/Sox6fl/fl) to determine the impact of specific Sox6 ablation in renin expression during JG cell expansion and renal artery stenosis renal induced hypertension.

Methods

In vivo: JG cell expansion was induced by 10 days of low sodium diet (0.01% Na) and furosemide (0.1 mg/g body weight). Renal artery stenosis was induced by the 2 Kidney 1 clip (2K1C) Goldblatt model; renin is overexpressed in the clipped kidney with renin expression being repressed in contralateral kidney. In vitro: primary renal Mesenchymal Stromal Cells (MSC) were isolated from wild‐type mice. MSC were differentiated into renin expressing cells by 7 days I&F (3‐isobutyl‐methyl‐xanthine (IBMX)‐100 uM and Forskolin‐10 uM) treatment.

Results

I&F induced renin expression in MSCs (Renin relative expression to gapdh 0.0153±0.005, n=3, P= 0.05, no renin expression in control MSCs). In the Ren1dCre/Sox6fl/fl there was no difference in blood pressure or heart rate at base line. However, under conditions that promote JG cell expansion, Sox6 ablation halted the increase in the number of JG cells (8.75 fold decrease, n= 6 to 9, P= 0.001). In our preliminary study we found that specific knock‐out of Sox6 in renin expressing cells protected the kidney against renal artery stenosis injury when compared to control mice (two mice per group). After renal artery stenosis, wild‐type kidneys were one‐third the size of Ren1dCre/Sox6fl/fl kidneys. In addition, renin expression was ~50% higher in the wild‐type group.

Conclusion

Our data indicates that Sox6 plays a novel role in renal physiology; modulating renin expression during pathological conditions. These results will aid in the discovery of a novel transcriptional regulatory network controlled by Sox6, involved in blood pressure regulation. Identification of this novel pathway and its regulators may lead to new therapies for blood pressure control aiming at decreasing cardiovascular disease in hypertensive patients.

Support or Funding Information

Research was supported by American Heart Association Scientist Development Award to JAG (16SDG29880007), the Vanderbilt University Medical Center Faculty Research Scholars Program, and NHLBI Research Scientist Development Grant 1K01HL135461‐01 to JAG

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Prospective Study To Investigate The Prevalence Of The 90 kDa Isoform Of Angiotensin Converting Enzyme In Vitória ‐ Brazil
Authors: Gomes Andreia Cristina , Fernandes Fernanda Barrinha , do Carmo Franco Maria , Mill Jose Geraldo Carmo , Casarini Dulce Elena
Published: June 2021

Hypertension is considered a worldwide public health problem and identified as a risk factor for cardiovascular morbidity and mortality. The Renin Angiotensin System (RAS) has been a focus of interest of researchers in the area of hypertension both for the identification of its etiopathogenesis and for its treatment. In order to identify the components involved in the onset of hypertension and the participation of Angiotensin I Converting Enzyme (ACE) in this problem, the RAS has been the object of many studies. ACE has a great physiological importance for converting angiotensin I (Ang I) to angiotensin II (Ang II), a potent vasoconstrictor. Some papers suggest the association of ACE isoforms, especially the 90 kDa isoform, with hypertension. The aim of this study was to investigate the association between ACE isoforms and the presence of arterial hypertension in the second phase of the prospective study (MONICA Project) in the population of Vitória ‐ ES, Brazil.

Methods

The demographic, clinical and biochemical parameters of 220 individuals were evaluated. Urine samples were concentrated and ACE isoforms were identified by the Western Blotting technique.

Results

The groups were classified as Group 1 (presence of isoforms with 65, 90 and 190 KDa); Group 2 (presence of 65 and 90 kDa isoforms) and Group 3 (presence of 65 and 190 kDa isoforms). The results showed a high prevalence of the 90 kDa isoform with a higher incidence of hypertension (higher in group 2) after five years of segment. The groups containing 90 kDa isoform showed higher systolic and diastolic pressure profiles in the second phase and the frequency of normotensives expressing the isoforms with 65 and 190 kDa was higher than that the hypertensive ones. Loss of isoform expression at 190 kDa increases the chances of developing hypertension as well as family history of hypertension.

Conclusion

The results suggest the 90‐kDa N‐domain isoform as a possible biological marker of hypertension, which confirms the results obtained in the first phase of the study.

Support or Funding Information

CNPq and FAPESP

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
CNS‐Specific Leptin Receptor Deficiency Impairs Cardiac Reserve
Authors: Gava Fabio N. , Moak Sydney P. , do Carmo Jussara M.
Published: June 2021

We previously showed that leptin deficiency leads to reduced myocardial reserve independent of changes in body weight, and that leptin replacement in non‐obese ob/ob mice completely restored ejection fraction (EF) responses to a cardiovascular stress test. Whether central nervous system (CNS) leptin receptor (LepR) activation contributes to normal myocardial reserve during increased cardiac stress is unknown. In this study we examined if deletion of LepR specifically in the CNS alters cardiovascular responses to a stress test induced by dobutamine in 22 week old mice. LepR/Nestin‐Cre mice with LepR deleted in the CNS were generated by breeding LepRflox/flox mice with Nestin‐Cre mice. Male LepR/Nestin‐Cre (n=4) and WT control (n=5) mice were instrumented for continuous infusion of saline and progressively increasing doses of dobutamine (2–12 ng/g body wt/min, 2 min at each dose). Long and short axis left ventricle dimensions were obtained before and one minute after each dose of dobutamine using a 30 MHZ transducer (VEVO2100®). Compared to WT, LepR/Nestin‐Cre mice were heavier (73±3 vs 34±1 g) due to hyperphagia (5.5±0.5 vs 3.8±0.5 g food/day), normoglycemic (174±10 vs 180±11 mg/dL), hyperleptinemic (109±1.5 vs 6.5±0.9 ng/mL), and hyperinsulinemic (119±23 vs 10±3 mU/mL). Baseline heart rate (HR) was similar in LepR/Nestin‐Cre (433±16 bpm) and WT (421±28 bpm) mice. Baseline EF was significantly higher in LepR/Nestin‐Cre (80±2%) compared to WT (66±4%) mice. Dobutamine infusion (4 ng/g/min) decreased average HR by 47±15 in LepR/Nestin‐Cre and increased HR by 41±11 bpm in WT mice. Dobutamine increased EF by 28±5% in WT mice but no significant change (4±4%) occurred in LepR/Nestin‐Cre mice. These results show that despite significant increases in plasma leptin concentration and presumably stimulation of cardiac LepR, CNS LepR deficiency leads to reduced myocardial reserve in response to a cardiovascular stress test in male mice. (NHLBI‐PO1HL51971, NIGMS P20GM104357)

Support or Funding Information

NHLBI‐PO1HL51971, NIGMS P20GM104357

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
What the Current Arterial‐Ventricular Coupling Index Fails to Tell Us
Authors: Kerkhof Peter L. , Merillon Jean Paul , Handly Neal
Published: June 2021

BACKGROUND

The arterial‐ventricular (AV) coupling index (k) is often employed to evaluate ventricular performance in relation to arterial properties. The index k is defined as the ratio of end‐systolic (ES) ventricular elastance (Emax) and effective arterial elastance (Ea). Emax describes the nonlinear trajectory of ventricular pressure (P) and volume (V) at end‐systole. Within a sufficiently small range Emax may be approximated by ESP/(ESV − Vo), where Vo is the extrapolated volume axis intercept. Likewise Ea is defined as ESP/SV, where SV is stroke volume. It may be convenient to index (i) volumes for body surface area (BSA). However, in the formula for k, both ESP and BSA cancel out, resulting in a dimensionless index. Unfortunately, the term Vo is neglected in most studies.

AIMS

This investigation addresses the question if AV coupling can be described completely by k, or if an additional cofactor (kc) may be necessary, regardless of inclusion of Vo or not.

METHODS

Since k concerns a ratio, information is lost compared to the constitutive details available, namely SV and (ESV‐Vo). Plotting SV vs (ESV‐Vo) shows k as the tangent, while the missing companion of k (here termed kc) can be identified as the distance from the origin. The Pythagorean theorem states that kc equals the root of the sum of SV and (ESV‐Vo) each squared. We calculated the possible association between k and kc for published data (Asanoi et al., Circ Res 1989;65: 483–493) on 12 healthy individuals and 16 patients with cardiac dysfunction including heart failure. In their study Emax and Vo were obtained via linear regression analysis on more than 5 data points obtained by combined 2D echocardiography and variation of ESP as induced by phenylephrine and sodium nitroprusside i.v., respectively. While omitting Vo (indicated by the prime for k and kc), we also calculated k′ and kc′.

RESULTS

Although there is an association k′ = 0.486 k + 0.4861, R2 = 0.3928 (P<0.001), N=28, the connection strongly diverges for k>1, where a value between 1 and 2 is supposed to correspond with optimal matching. The kc relates to k via kc = −17.22 ln (k) + 71.57, R2 = 0.384, N=28, and likewise kc′ to k′ as kc′ = −31.81 ln (k′) + 77.96, R2 = 0.624, N=28.

CONCLUSIONS

The dimensionless metric k is only characterized by SV, ESV and Vo, not by end‐systolic pressure level. The companion kc depends on the same variables, and has the dimension of volume (index). AV‐coupling is more completely characterized by the combination of k and kc. Consideration of the value of k in isolation provides an incomplete description of AV‐coupling characteristics, regardless of the fact whether Vo is included.

Support or Funding Information

none

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Hemoglobin Inhibits Uptake of Filtered Proteins by Proximal Tubule Cells: Implications for Sickle Cell Disease and Vitamin D Status
Authors: Eshbach Megan L. , Kaur Amandeep , Rbaibi Youssef , Agarwal Yash , Zhang Qiangmin , Nolin Thomas D. , Tejero Jesús , Weisz Ora A.
Published: June 2021

Proximal tubule (PT) dysfunction, including tubular proteinuria, is a significant complication in sickle cell disease (SCD) that can eventually lead to chronic kidney disease. The PT is especially susceptible to cytotoxic damage, and tubular dysfunction in SCD is thought to result from prolonged exposure to hemoglobin (Hb) released from damaged red blood cells. Filtered Hb dimers are internalized into PT cells upon binding to the multiligand receptors megalin and cubilin. These receptors bind to numerous filtered proteins, including albumin and vitamin D binding protein, and are important for maintaining protein‐free urine and vitamin D homeostasis. We hypothesized that toxicity from exposure to Hb could impair PT cell endocytic function, causing tubular proteinuria. Using a fluorescence‐based protein uptake assay in a PT cell culture model, we found that concentrations of Hb predicted to enter the tubule lumen during hemolytic crisis profoundly inhibit the uptake of other megalin/cubilin ligands (albumin and vitamin D binding protein) by PT cells. These effects were independent of heme reduction state, occurred in the absence of a cytotoxic response, and appear to be due to direct competition for megalin/cubilin binding. The Glu7Val mutant that causes SCD was equally effective at inhibiting albumin uptake compared with wild type Hb. Haptoglobin restored albumin uptake in the presence of Hb, suggesting that haptoglobin binding to the Hb αβ dimer‐dimer interface interferes with Hb binding to megalin/cubilin. Using these data, we established a robust, scalable assay that enables us to screen for selective inhibitors of Hb uptake that preserve PT function. Our studies suggest that the primary cause of tubular proteinuria in SCD is impaired endocytosis of megalin/cubilin ligands due to competition from filtered Hb, rather than toxicity. Our data also suggest a potential explanation for the vitamin D deficiency commonly observed in sickle cell patients. Current studies are focused on characterizing the effects of Hb on vitamin D metabolism and signaling in PT cells.

Support or Funding Information

National Institutes of Health RO1 DK101484, RO1 DK100357, P30 DK079307, T32 DK061296, TL1 TR001858; Pittsburgh Heart, Lung, and Blood Vascular Medicine Institute P3HVB pilot grant

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Resveratrol Exerts Dose‐response Anti‐fibrotic and Pro‐fibrotic Effect in Renal Tubular Epithelial Cells
Authors: Liu Shuyun , Zhao Meng , Zhou Yijie , Li Lan , Yuan Yujia , Wang Chengshi , Chen Younan , Cheng Jingqiu , Lu Yanrong , Liu Jingping
Published: June 2021

Background

Renal fibrosis is the common pathological feature of chronic kidney disease (CKD) that finally leads to end‐stage renal disease (ESRD) and renal failure. Resveratrol (RSV) has been widely used as nutrition supplement for metabolic diseases and anti‐cancer therapy, but its potential risk on kidney health has not been fully evaluated. In this study, we investigated the comprehensive effect of RSV on renal fibrosis in human tubular epithelial cells (TECs) line HK‐2.

Methods

The epithelial‐mesenchymal transition (EMT) in HK‐2 cells was induced by TGF‐β, and EMT cells were treated with a series concentration of RSV. The alteration of cell phenotype and EMT markers including E‐cadherin (E‐cad), ɑ‐smooth muscle actin (ɑ‐SMA) and fibronectin (FN) were analyzed. In addition, the effects of RSV on cell viability, LDH release, oxidative stress, mitochondrial function and cytoskeleton remodeling in HK‐2 cells were also measured.

Results

TGF‐β induced obvious pro‐fibrotic phenotype (reduced E‐cad, increased ɑ‐SMA and FN expression) and down‐regulated Sirt1 in HK‐2 cells, while low doses RSV (5–20 μM) suppressed the TGF‐β induced EMT via Sirt1‐dependent deacetylation of Smad3/4 mechanism. However, long‐term (72 hrs) of higher doses RSV (≥ 40 μM) treatment lost its anti‐fibrotic role in EMT cells despite sustained activation of Sirt1. In addition, higher doses RSV directly inhibited cell viability, induced oxidative stress and LDH release in HK‐2 cells. Further results revealed that higher doses RSV not only induced mitochondria dysfunction (elevated fragments and mtROS, reduced levels of ATP and mitochondrial biogenesis proteins), but also caused abnormal F‐actin redistribution and Rock1 signals activation.

Conclusion

This study highlighted that RSV activated dose‐response anti‐fibrotic and pro‐fibrotic effect in TECs, and the adverse effect of RSV was respected to mitochondrial oxidative stress and Rock1‐mediated disordered cytoskeleton remodeling. Therefore, RSV dose should be carefully considered when used in patients with impaired kidney function.

Support or Funding Information

This work was supported by grants from National Natural Science Foundation of China (31200754, 81571808).

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Arginase‐2 protects the kidney against ischemia‐reperfusion injury
Authors: Ansermet Camille , Centeno Gabriel , Rotman Samuel , Barras Jean‐Luc , Dattner Nicolas , Firsov Dmitri
Published: June 2021

Arginase‐2 (Arg2) is an enzyme converting the L‐arginine in urea and L‐ornithine. As it is expressed in extra‐hepatic tissues lacking a complete urea cycle, it may play a role in polyamines production, nitric oxide regulation or energy supply.

Arg2 expression has been shown to be induced by hypoxia, in vitro and in vivo, and interestingly, its upregulation has been observed in certain animals naturally exposed to low oxygen concentration. Moreover, Arg2 overexpression has been associated with many pathological conditions, as diabetes, atherosclerosis, cardiac and renal ischemia reperfusion and cirrhosis, or after toxic compounds exposure (cadmium, cisplatin). Although Arg2 inhibition seems to improve the disease severity, the role of this upregulation remains unknown.

We hypothesized that Arg2 upregulation in renal cells following an ischemic event helps the cells to overcome the occlusion‐induced stress. To address this question, we used the Pax8‐rtTA‐driven Cre expression system, allowing a conditional inactivation of Arg2 in mouse renal tubule.

The conditional Arg2 knockout mice (cKO) subjected to 25‐minute renal ischemia followed by 24‐hour reperfusion show a more severe acute kidney injury (AKI) compared to Control mice and develop a transient renal Fanconi syndrome characterized by polyuria, albuminuria, aminoaciduria, hypercalcuria, hypermagnesuria and phosphaturia. When the reperfusion time increases to 2 weeks, urinary parameters normalize in both groups, but cKO mice show an increase in renal insufficiency markers compared to Control mice, with higher plasma levels of asymmetric (ADMA) and symmetric (SDMA) dimethylarginine.

Taken together, these results support a relevant role for Arg2 in renal ischemia recovery.

Support or Funding Information

Swiss National Science Foundation Research grants 31003A‐149440 (to D.F.)

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The protective effect of estrogen on cisplatin‐induced cytotoxicity of HK‐2 cells
Authors: Liu Yu‐Wen , Lin Shiuan‐Yea , Chen Yu‐Tong , Lu Tzong‐Shi , Fu Yaw‐Syan
Published: June 2021

Introduction and hypothesis

Cisplatin is a widely used chemotherapeutic agent and has significant renal toxicity. Estrogen is a major sex hormone in females, and previous studies have shown that estrogen has many physiological protective effects. HK‐2 cell line is an immortalized proximal tubule epithelial cell line from healthy men. In this study, we investigated the protective roles of estrogen on cisplatin‐induced nephrotoxicity by the in vitro HK‐2 cell model.

Methods

HK‐2 Cells were pretreated with 17β‐estradiol (0~20 nM), estrogen receptor agonists, and estrogen receptor antagonists for 24 hours respectively. All groups of cells were followed treated with cisplatin (0–15 mg/ml) for 24 hours. The cell survival rate, proliferation, morphology were analyzed by ELISA. The apoptosis/necrosis were analyzed by Annexin‐V/PI staining using flow cytometry. Estrogen receptors and apoptosis related proteins expressions were confirmed by Western blotting.

Results

All three types of estrogen receptors could be expressed by the HK‐2 cells. In cisplatin‐induced nephrotoxicity cell model, 17β‐estradiol pretreatment have higher cell survival rate than vehicle when dose larger than 10 nM. The Annexin‐V positive apoptotic cells and caspase‐3 expressions in 17β‐estradiol pretreated group is significant lower than vehicle control. The three types of estrogen agonists exert the protective effects in cisplatin‐induced cytotoxicity, and acted on the G protein‐coupled estrogen receptor (GPER) is the most effective. In addition, blocked GPER also significantly accentuated cytotoxicity of cisplatin treated HK‐2 cells.

Conclusions

Our data suggested that estrogen pretreatment could protect HK‐2 cells from cisplatin induced cytotoxicity, and this protective effect occurs mainly through the GPER pathway. It may offer a novel therapeutic strategy for cisplatin‐induced nephrotoxicity. Further investigation into the molecular mechanisms and clinical applications are needed.

Support or Funding Information

KMU‐TP105E37

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
GYY4137 Mitigates Caveolin‐dependent Renal Remodeling in Hyperhomocysteinemia
Authors: John AM Sashi Papu , Pushpakumar Sathnur , Sen Utpal
Published: June 2021

Introduction

Hyperhomocysteinemia (HHcy), an increase in plasma homocysteine levels induces collagen deposition by causing imbalance between MMPs and TIMPs leading to fibrosis, and predisposing hypertension. HHcy also decreases the endogenous production of hydrogen sulfide (H2S) and homocysteinylates endothelial nitric‐oxide synthase (eNOS) resulting in further increase of vascular resistance. In the contrary, deletion of a membrane protein Caveolin‐1 (Cav‐1) is known to mitigate hypertension. However, the interplay between Caveolin, eNOS and MMPs/TIMPs and the role of H2S in HHcy associated renovascular remodeling and hypertension remains largely unknown. We tested the hypothesis that GYY4137, a H2S donor mitigates hyperhomocysteinemic effect in renal microvasculature and thus normalizes vascular tone.

Methods

B6.Cg‐Cav1(Cav‐1) mice representing caveolae protein 1 knock‐out and C57BL6/J (WT) mice were treated without or with GYY4137 (0.5 mg/Kg/d, IP) and supplemented without or with Hcy (2% in diet) for a period of 8 weeks.

Results

HHcy decreased plasma H2S levels, upregulated Cav1 and decreased eNOS activity in kidney. HHcy resulted in the upregulation of mRNA and protein levels of matrix metalloproteinases (MMPs) ‐2,‐9,‐1,‐8,‐13 and decreased the activities of tissue inhibitor of metalloproteinases (TIMPs) ‐1,‐2,‐3,‐4. Immunohistochemistry showed increased collagen IV deposition in the glomerular and interstitial areas. GYY4137 treatment reversed these changes in HHcy. In conclusion, our data suggests that H2S mitigates renovascular remodeling by modulating Cav‐1, eNOS and MMPs/TIMPs in HHcy.

Support or Funding Information

This study was supported by National Institute of Health Grant ‐ DK104653 (to U.S.)

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Adipose Triglyceride Lipase Activity in Adipocytes, but Not Skeletal Myocytes, Is Essential for Maintaining Normal Contractile Function in Both Young and Old Mice
Authors: Wahler Sue , Ambrosio Fabrisia , Kershaw Erin , Sitnick Mitchell
Published: June 2021

The production of contractile force is a key physiological function of skeletal muscle which relies on many factors in order to reach maximal force output. While the working muscle requires sufficient energy substrates to maintain work, for maximal contractile force development to occur, skeletal muscle requires multiple motor units to be recruited thereby allowing fibers to unite their contractions. This recruitment process depends on multiple factors such as muscle fiber size, lack of injury and, neuromuscular signaling. As such, maximal force output is often an indicator of overall skeletal muscle quality, with lower quality (e.g. no infiltration of fat or fibrotic tissue) or injured muscle having impaired maximal force production. Adipose Triglyceride Lipase (ATGL) is the rate‐limiting enzyme mediating intracellular triacylglycerol hydrolysis and plays a key role in the mobilization of fatty acids during exercise. However, it likely also plays a role in skeletal muscle physiology as a total loss of ATGL leads to a dystrophic phenotype with progressive myopathies, weakness and impaired exercise performance. In order to determine the role between ATGL mediated lipolysis and skeletal muscle functional performance, we generated adipocyte or skeletal myocyte‐specific ATGL knockout mice and assessed their capacity for force production in both young and older animals.

We found that the loss of ATGL‐mediated lipolysis in either muscle or adipose had no effect on twitch force or fatigue resistance compared to wild‐type controls. However, the loss of ATGL activity in adipose tissue resulted in severe impairments in their force frequency profile, particularly at frequencies that elicit a summation of contractions. Together this suggests that adipocyte ATGL‐mediated lipolysis could play a significant role in skeletal muscle function and overall muscle quality. For further analysis, we are planning to investigate changes in gene and protein expression alongside histochemical assessment of muscle architecture and injury to derive a possible mechanism for our observed phenotype phenotype.

Support or Funding Information

This work was supported by NIH R01DK090166, HHMI Physician‐Scientist Early Career Award, and U. of Pittsburgh Dept of Medicine Junior Scholar Award; NIH T32 DK007052; Erwin Schrödinger Fellowship‐J3221‐B19, the Claude D. Pepper Center for Aging Pilot award, and the MSU Science, Honors, and Innovation Program

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Mechanisms of Exercise Intolerance in Heart Failure with Reduced Ejection Fraction: Influence of COPD
Authors: Smith Joshua R. , Van Iterson Erik H. , Olson Thomas P.
Published: June 2021

Introduction

Exercise intolerance is a hallmark of heart failure with reduced ejection fraction (HFrEF) resulting from a variety of factors including comprised oxygen delivery. A common comorbidity of HFrEF is chronic obstructive pulmonary disease (COPD), which is independently associated with reduced exercise tolerance and cardiac output (Q) as well as peripheral dysfunction similar to HFrEF. It is currently unknown if HFrEF and coexisting COPD (HFrEF+COPD) exhibit worsened exercise tolerance and whether the mechanisms thereof are similar to HFrEF alone. We hypothesized that patients with HFrEF+COPD demonstrate further reductions in peak VO2 and workload subsequent to a lower peak Q and arterio‐mixed venous O2 content difference (C(a‐v)O2) compared to HFrEF alone.

Methods

HFrEF+COPD (n=16) and HFrEF (n=17) (age: 57±7 vs 54±6 yrs; EF%: 20±5 vs 21±5; height: 173±7 vs 174±7 cm; weight: 88±14 vs 86±17 kg; all p>0.18) underwent peak exercise testing during right heart catheterization. At rest and peak exercise, invasive hemodynamic, cardiac pressures, and arterial pressures were performed. Heart rate and oxygen uptake (VO2) were measured at rest and peak exercise via 12‐lead ECG and metabolic measurement system, respectively. Convective oxygen delivery was calculated as Q multiplied by CaO2.

Results

Peak exercise VO2 and workload were lower in HFrEF+COPD compared to HFrEF (7.0±1.9 vs. 9.9±2.7 mL/min/kg; 34±7 vs. 45±12 watts; both p<0.01). At peak exercise, Q and stroke volume were lower in HFrEF+COPD than HFrEF (4.8±1.3 vs. 7.0±3.0 L/min; 52±16 vs. 75±28 mL; both p<0.01). Significant relationships existed between delta VO2 and Q (peak exercise minus resting) in HFrEF+COPD and HFrEF (r=0.84 and r=0.89; both p<0.01); however, HFrEF+COPD had a significantly lower slope (p=0.02). Peak exercise C(a‐v)O2 was not different between HFrEF+COPD and HFrEF (12.9±2.3 vs. 12.8±2.6 mL/dL; p=0.89). No differences were present in heart rate or hemoglobin at peak exercise (p>0.73). Delta VO2 and C(a‐v)O2 was significantly related for HFrEF+COPD (r=0.68; p<0.01), but not HFrEF (r=0.14, p=0.57). At peak exercise, HFrEF+COPD had lower convective oxygen delivery (845±239 vs. 1230±517 mL/min; p<0.01).

Conclusions

Patients with HFrEF and concurrent COPD demonstrate worsened exercise tolerance compared to HFrEF resulting from reduced oxygen delivery. These data suggest HFrEF with COPD exhibit more severe central and peripheral abnormalities than HFrEF alone.

Support or Funding Information

NHLBI RO1 HL126638

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Influence of Inspiratory Muscle Training on Sympatho‐excitation in Healthy Young Adults
Authors: Foulds Tatum E. , Delucia Claire M. , Ramos Barrera Guadalupe E. , Bailey E. Fiona
Published: June 2021

Inspiratory muscle training (IMT) lowers blood pressure in healthy young adults and adults with obstructive sleep apnea (Vranish & Bailey, 2015; 2016). Importantly, in healthy young adults, 6 weeks IMT also is associated with significant declines in systemic vascular resistance (Delucia et al. 2017). In light of these outcomes, in the current study we test the hypothesis that 6 weeks IMT reduces sympathetic outflow. Accordingly, we recruited healthy college‐aged students and randomly allocated them to either IMT or to Sham training groups. At intake (Week 1) and study completion (Week 6) we recorded MSNA as subjects performed sympatho‐excitatory challenges as follows: Valsalva maneuver, Mueller maneuver, submaximal grip test, cold pressor test, and mental stress tests (Stroop and mental arithmetic). Additionally, we performed weekly (blinded) assessments of systolic and diastolic blood pressures (SBP and DBP), and assessed maximal inspiratory pressure and respiratory function. Our preliminary results indicate subjects in the IMT group have lowered systolic (114.3 ± 3.4 mmHg vs. 106.7 ± 1.8 mmHg, p=0.0115) and diastolic (68.39 ± 1.58 mmHg vs. 63.5 ± 0.97 mmHg, p=0.0413) blood pressures relative to Sham trained subjects (SBP 114.7 ± 2.94 mmHg vs. 108.9 ± 1.34 mmHg and DBP 72.47 ± 3.29 mmHg vs. 69.99 ± 1.75 mmHg). Consistent with our hypothesis, preliminary analyses highlight lowered sympathetic burst frequency in the IMT group during Valsalva maneuvers (Week 1:15 ± 2.2 bursts per 15 seconds vs. Week 6: 11 ± 1.5 bursts per 15 seconds) as compared to Sham trained subjects (Week 1:12.13 ± 1.48 bursts per 15 seconds vs. Week 6:11.63 ± 0.83 bursts per 15 seconds). Data collection is ongoing however, our early findings show a reduction in sympathetic outflow during respiratory challenges which may underpin declines in peripheral resistance and blood pressure seen in healthy young adults following IMT.

Support or Funding Information

This work was supported by start up monies awarded to EFB.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.