Fatty acid metabolism promotes TRPV4 activity in lung microvascular endothelial cells in pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a morbid disease characterized by significant lung endothelial cell (EC) dysfunction. Prior work has shown that microvascular endothelial cells (MVECs) isolated from animals with experimental PAH and patients with PAH exhibit significant abnormalities in metabolism and calcium signaling. With regards to metabolism, we and others have shown evidence of increased aerobic glycolysis and evidence of increased utilization of alternate fuel sources (such as fatty acids) in PAH EC. In the realm of calcium signaling, our prior work linked increased activity of the transient receptor potential vanilloid-4 (TRPV4) channel to increased proliferation of MVECs isolated from the Sugen/Hypoxia rat model of PAH (SuHx-MVECs). However, the relationship between metabolic shifts and calcium abnormalities was not clear. Specifically, whether shifts in metabolism were responsible for increasing TRPV4 channel activity in SuHx-MVECs was not known. In this study, using human data, serum samples from SuHx rats, and SuHx-MVECs, we describe the consequences of increased MVEC fatty acid oxidation in PAH. In human samples, we observed an increase in long-chain fatty acid levels that was associated with PAH severity. Next, using SuHx rats and SuHx-MVECs, we observed increased intracellular levels of lipids. We also show that increasing intracellular lipid content increases TRPV4 activity, whereas inhibiting fatty acid oxidation normalizes basal calcium levels in SuHx-MVECs. By exploring the fate of fatty acid-derived carbons, we observed that the metabolite linking increased intracellular lipids to TRPV4 activity was ß-hydroxybutyrate (BOHB), a product of fatty acid oxidation. Finally, we show that BOHB supplementation alone is sufficient to sensitize the TRPV4 channel in rat and mouse MVECs. Returning to humans, we observe a transpulmonary BOHB gradient in human patients with PAH. Thus, we establish a link between fatty acid oxidation, BOHB production, and TRPV4 activity in MVECs in PAH. These data provide new insight into metabolic regulation of calcium signaling in lung MVECs in PAH.NEW & NOTEWORTHY In this paper, we explore the link between metabolism and intracellular calcium levels in microvascular endothelial cells (MVECs) in pulmonary arterial hypertension (PAH). We show that fatty acid oxidation promotes sensitivity of the transient receptor potential vanilloid-4 (TRPV4) calcium channel in MVECs isolated from a rodent model of PAH.

Premorbid weight in pulmonary arterial hypertension.

Relationships between obesity and outcomes in pulmonary arterial hypertension (PAH) are complex. Previous work suggested obesity, occurring alongside PAH, may be associated with better survival. In our work, we suggest obesity prior to PAH development is associated with worse survival. This may add a novel temporal element to the "obesity-paradox."

Transpulmonary amino acid metabolism in the sugen hypoxia model of pulmonary hypertension.

In pulmonary artery hypertension (PAH), emerging evidence suggests that metabolic abnormalities may be contributing to cellular dysfunction in PAH. Metabolic abnormalities such as glycolytic shift have been observed intracellularly in several cell types in PAH, including microvacular endothelial cells (MVECs). Concurrently, metabolomics of human PAH samples has also revealed a variety of metabolic abnormalities; however the relationship between the intracellular metabolic abnormalities and the serum metabolome in PAH remains under investigation. In this study, we utilize the sugen/hypoxia (SuHx) rodent model of PAH to examine the RV, LV and MVEC intracellular metabolome (using targeted metabolomics) in normoxic and SuHx rats. We additionally validate key findings from our metabolomics experiments with data obtained from cell culture of normoxic and SuHx MVECs, as well as metabolomics of human serum samples from two different PAH patient cohorts. Taken together, our data, spanning rat serum, human serum and primary isolated rat MVECs reveal that: (1) key classes of amino acids (specifically, branched chain amino acids-BCAA) are lower in the pre-capillary (i.e., RV) serum of SuHx rats (and humans); (2) intracellular amino acid levels (in particular BCAAs) are increased in SuHx-MVECs; (3) there may be secretion rather than utilization of amino acids across the pulmonary microvasculature in PAH and (4) an oxidized glutathione gradient is present across the pulmonary vasculature, suggesting a novel fate for increased glutamine uptake (i.e., as a source of glutathione). in MVECs in PAH. In summary, these data reveal new insight into the shifts in amino acid metabolism occurring across the pulmonary circulation in PAH.

Metabolomic Signatures Associated With Pulmonary Arterial Hypertension Outcomes.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a complex disease characterized by progressive right ventricular (RV) failure leading to significant morbidity and mortality. Investigating metabolic features and pathways associated with RV dilation, mortality, and measures of disease severity can provide insight into molecular mechanisms, identify subphenotypes, and suggest potential therapeutic targets. METHODS: We collected data from a prospective cohort of PAH participants and performed untargeted metabolomic profiling on 1045 metabolites from circulating blood. Analyses were intended to identify metabolomic differences across a range of common metrics in PAH (eg, dilated versus nondilated RV). Partial least squares discriminant analysis was first applied to assess the distinguishability of relevant outcomes. Significantly altered metabolites were then identified using linear regression, and Cox regression models (as appropriate for the specific outcome) with adjustments for age, sex, body mass index, and PAH cause. Models exploring RV maladaptation were further adjusted for pulmonary vascular resistance. Pathway enrichment analysis was performed to identify significantly dysregulated processes. RESULTS: A total of 117 participants with PAH were included. Partial least squares discriminant analysis showed cluster differentiation between participants with dilated versus nondilated RVs, survivors versus nonsurvivors, and across a range of NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels, REVEAL 2.0 composite scores, and 6-minute-walk distances. Polyamine and histidine pathways were associated with differences in RV dilation, mortality, NT-proBNP, REVEAL score, and 6-minute walk distance. Acylcarnitine pathways were associated with NT-proBNP, REVEAL score, and 6-minute walk distance. Sphingomyelin pathways were associated with RV dilation and NT-proBNP after adjustment for pulmonary vascular resistance. CONCLUSIONS: Distinct plasma metabolomic profiles are associated with RV dilation, mortality, and measures of disease severity in PAH. Polyamine, histidine, and sphingomyelin metabolic pathways represent promising candidates for identifying patients at high risk for poor outcomes and investigation into their roles as markers or mediators of disease progression and RV adaptation.

Improved hospitalization rates in a specialty center for heart failure with preserved ejection fraction and pulmonary hypertension.

Heart failure with preserved ejection fraction can be complicated by pulmonary hypertension. We designed a retrospective study to provide supporting evidence for referral to specialty care centers. Specialty care centers improved hospitalizations but not mortality-in part due to more aggressive medication management and guideline-directed monitoring.

Thyroid-stimulating hormone and mortality in pulmonary arterial hypertension.

INTRODUCTION: Pulmonary arterial hypertension (PAH) remains a serious and life-threatening illness. Thyroid dysfunction is relatively understudied in individuals with PAH but is known to affect cardiac function and vascular tone in other diseases. The aim of this observational study was to evaluate the association between thyroid-stimulating hormone (TSH), mortal and non-mortal outcomes in individuals with PAH. METHODS: The Seattle Right Ventricle Translational Science (Servetus) Study is an observational cohort that enrolled participants with PAH between 2014 and 2016 and then followed them for 3 years. TSH was measured irrespective of a clinical suspicion of thyroid disease for all participants in the cohort. Linear regression was used to estimate the relationships between TSH and right ventricular basal diameter, tricuspid annular plane systolic excursion and 6-minute walk distance. Logistic regression was used to estimate the relationship with New York Heart Association Functional Class, and Cox proportional hazards were used to estimate the relationship with mortality. Staged models included unadjusted models and models accounting for age, sex at birth and aetiology of pulmonary hypertension with or without further adjustment for N-terminal-pro hormone brain natriuretic peptide. RESULTS: Among 112 participants with PAH, TSH was strongly associated with mortality irrespective of adjustment. There was no clear consistent association between TSH and other markers of severity in a cohort with PAH. DISCUSSION: This report reinforces the important observation that TSH is associated with survival in patients with PAH, and future study of thyroid dysfunction as a potential remediable contributor to mortality in PAH is warranted.

Extracellular Volume and Global Longitudinal Strain Both Associate With Outcomes But Correlate Minimally.

OBJECTIVES: This study examined how extracellular volume (ECV) and global longitudinal strain (GLS) relate to each other and to outcomes. BACKGROUND: Among myriad changes occurring in diseased myocardium, left ventricular imaging metrics of either the interstitium (e.g., ECV) or contractile function (e.g., GLS) may consistently associate with adverse outcomes yet correlate minimally with each other. This scenario suggests that ECV and GLS potentially represent distinct domains of cardiac vulnerability. METHODS: The study included 1,578 patients referred for cardiovascular magnetic resonance (CMR) without amyloidosis, and it quantified how ECV associated with GLS in linear regression models. ECV and GLS were then compared in their associations with incident outcomes (death and hospitalization for heart failure). RESULTS: ECV and GLS correlated minimally (R2 = 0.04). Over a median follow-up of 5.6 years, 339 patients experienced adverse events (149 hospitalizations for heart failure, 253 deaths, and 63 with both). GLS (univariable hazard ratio: 2.07 per 5% increment; 95% CI: 1.86 to 2.29) and ECV (univariable hazard ratio: 1.66 per 4% increment; 95% CI: 1.51 to 1.82) were principal variables associating with outcomes in univariable and multivariable Cox regression models. Similar results were observed in several clinically important subgroups. In the whole cohort, ECV added prognostic value beyond GLS in univariable and multivariable Cox regression models. CONCLUSIONS: GLS and ECV may represent principal but distinct domains of cardiac vulnerability, perhaps reflecting their distinct cellular origins. Whether combining ECV and GLS may advance pathophysiological understanding for a given patient, optimize risk stratification, and foster personalized medicine by targeted therapeutics requires further investigation.

Outcomes of Pulmonary Arterial Hypertension Are Improved in a Specialty Care Center.

BACKGROUND: Pulmonary arterial hypertension (PAH) is characterized by elevated pulmonary arterial pressures and is managed by vasodilator therapies. Current guidelines encourage PAH management in specialty care centers (SCCs), but evidence is sparse regarding improvement in clinical outcomes and correlation to vasodilator use with referral. RESEARCH QUESTION: Is PAH management at SCCs associated with improved clinical outcomes? STUDY DESIGNAND METHODS: A single-center, retrospective study was performed at the University of Pittsburgh Medical Center (UPMC; overseeing 40 hospitals). Patients with PAH were identified between 2008 and 2018 and classified into an SCC or non-SCC cohort. Cox proportional hazard modeling was done to compare for all-cause mortality, as was negative binomial regression modeling for hospitalizations. Vasodilator therapy was included to adjust outcomes. RESULTS: Of 580 patients with PAH at UPMC, 455 (78%) were treated at the SCC, comprising a younger (58.8 vs 64.8 years; P < .001) and more often female (68.4% vs 51.2%; P < .001) population with more comorbidities without differences in race or income. SCC patients demonstrated improved survival (hazard ratio, 0.68; P = .012) and fewer hospitalizations (incidence ratio, 0.54; P < .001), and provided more frequent disease monitoring. Early patient referral to SCC (< 6 months from time of diagnosis) was associated with improved outcomes compared with non-SCC patients. SCC patients were more frequently prescribed vasodilators (P < .001) and carried more diagnostic PAH coding (P < .001). Vasodilators were associated with improved outcomes irrespective of location but without statistical significance when comparing between locations (P > .05). INTERPRETATION: The UPMC SCC demonstrated improved outcomes in mortality and hospitalizations. The SCC benefit was multifactorial, with more frequent vasodilator therapy and disease monitoring. These findings provide robust evidence for early and regular referral of patients with PAH to SCCs.

Effects of the Rhinoplasty Maneuvers on Upper Lip Position and Incisor Show.

BACKGROUND: Smiling involves dynamic movements that include nasal tip descent and upper lip ascent. The effect of rhinoplasty on upper lip position is poorly described. METHODS: One hundred charts were reviewed in reverse chronologic order. Inclusion criteria were receiving one of the rhinoplasty maneuvers of interest, at least 6 months of follow-up, and pre- and postoperative photographs by a professional medical photographer with matching maximum smile extent and size. Maxillary incisor show was measured as the vertical distance between the caudal border of the upper lip and the caudal-most aspect of maxillary central incisors. Pre- and postoperative maxillary incisor show was compared by open versus closed approach and rhinoplasty maneuver with and without controlling for depressor septi nasi (DSN) release. RESULTS: Sixty-one females and fifteen males with a mean age of 39 years and mean follow-up of 16 months were included. No significant differences were seen between open versus closed approaches (p > 0.05). A decrease in postoperative maxillary incisor show was observed following columella strut, extended spreader graft, and DSN release (p < 0.05). No significant change in maxillary incisor show was seen after nasal spine graft, maxillary augmentation, tip rotation suture, shield graft, columella retraction, or tip suspension suture (p > 0.05). Patients undergoing footplate approximation and alar base resection had a significant decrease in maxillary incisor show (p < 0.05), but this significance was lost upon controlling for DSN release (p > 0.05). CONCLUSION: Certain caudal rhinoplasty maneuvers may result in decreased maxillary incisor show, particularly when the DSN muscles are involved. Examination of upper lip position and patient discussion is important for maximizing outcome. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Earlobe Rejuvenation: A Fat Grafting Technique.

BACKGROUND: The earlobe demonstrates stereotypical signs of aging, including wrinkles and volume depletion. OBJECTIVES: The purpose of this study is to review the outcome of the earlobe rejuvenation developed by the senior author. METHODS: We describe our earlobe rejuvenation technique refined over 10 years that uses fat grafting to the earlobe. Three raters assessed preoperative and postoperative photographs of 40 earlobes in 20 patients. Each earlobe was evaluated for volume deficiency, number of deep creases, depth of creases, and number of fine wrinkles. Inter-rater reliability was calculated. Earlobe length was also measured. RESULTS: Seventeen females and 3 males with average age of 63 years were followed for an average of 26 months. Postoperative improvements were observed in earlobe volume deficiency and number of fine wrinkles (P < .05). Improvements were seen in number and depth of creases and the earlobe height, but these were not significant (P > .05). No complications relating to the earlobe were observed in these patients. CONCLUSIONS: Fat grafting can be an effective means for earlobe rejuvenation. LEVEL OF EVIDENCE: 4 Therapeutic.

Spinal Muscular Atrophy Biomarker Measurements from Blood Samples in a Clinical Trial of Valproic Acid in Ambulatory Adults.

BACKGROUND: Clinical trials of therapies for spinal muscular atrophy (SMA) that are designed to increase the expression the SMN protein ideally include careful assessment of relevant SMN biomarkers. OBJECTIVE: In the SMA VALIANT trial, a recent double-blind placebo-controlled crossover study of valproic acid (VPA) in ambulatory adult subjects with SMA, we investigated relevant pharmacodynamic biomarkers in blood samples from SMA subjects by direct longitudinal measurement of histone acetylation and SMN mRNA and protein levels in the presence and absence of VPA treatment. METHODS: Thirty-three subjects were randomized to either VPA or placebo for the first 6 months followed by crossover to the opposite arm for an additional 6 months. Outcome measures were compared between the two treatments (VPA and placebo) using a standard crossover analysis. RESULTS: A significant increase in histone H4 acetylation was observed with VPA treatment (p = 0.005). There was insufficient evidence to suggest a treatment effect with either full length or truncated SMN mRNA transcript levels or SMN protein levels. CONCLUSIONS: These measures were consistent with the observed lack of change in the primary clinical outcome measure in the VALIANT trial. These results also highlight the added benefit of molecular and pharmacodynamic biomarker measurements in the interpretation of clinical trial outcomes.