HDL Cholesterol as a Marker of Disease Severity and Prognosis in Patients with Pulmonary Arterial Hypertension

Impact of reduced apolipoprotein A-I levels on pulmonary arterial hypertension

BACKGROUND

The significance of apolipoprotein A-I (ApoA-I) is the anti-inflammatory functional component of high-density lipoprotein, which needs to be further studied in relation to pulmonary arterial hypertension (PAH). This study aimed to identify the predictive value of ApoA-1 on the risk and prognosis of PAH, as well as the underlying anti-inflammatory mechanism.

METHODS

Proteomic analysis was conducted on lung tissue from 6 PAH patients and 4 lung donors. Prediction of risk and mortality risk factors associated with PAH in 343 patients used logistic analysis and Cox regression analysis, respectively. The protective function of ApoA-I was assessed in human pulmonary arterial endothelial cells (HPAEC), while its anti-inflammatory function was evaluated in THP-1 macrophages.

RESULTS

In the lung tissues of patients with PAH, 168 differentially expressed proteins were associated with lipid metabolism according to GO and KEGG enrichment analysis. A protein-protein interaction network identified ApoA-I as a key protein associated with PAH. Lower ApoA-I levels were independent risk factors for PAH and displayed a stronger predictive value for PAH mortality. Plasma interleukin 6 (IL-6) levels were positively correlated with risk stratification and was higher in PAH patients with lower ApoA-I levels. ApoA-I was downregulated in lung tissues of MCT-induced rats. ApoA-I could reduce IL-6-induced pro-proliferative and pro-migratory abilities of HPAEC and inhibit secretion of IL-6 from macrophages, which is compromised under hypoxic conditions.

CONCLUSION

Our study identified the significance of ApoA-I as a biomarker for predicting the survival outcome of PAH patients, which might relate to its altered anti-inflammatory properties.

Identification of Zip8-correlated hub genes in pulmonary hypertension by informatic analysis

Background

Pulmonary hypertension (PH) is a syndrome characterized by marked remodeling of the pulmonary vasculature and increased pulmonary vascular resistance, ultimately leading to right heart failure and even death. The localization of Zrt/Irt-like Protein 8 (ZIP8, a metal ion transporter, encoded by SLC39A8) was abundantly in microvasculature endothelium and its pivotal role in the lung has been demonstrated. However, the role of Zip8 in PH remains unclear.

Methods

Bioinformatics analysis was employed to identify SLC39A8 expression patterns and differentially expressed genes (DEGs) between PH patients and normal controls (NC), based on four datasets (GSE24988, GSE113439, GSE117261, and GSE15197) from the Biotechnology Gene Expression Omnibus (NCBI GEO) database. Gene set enrichment analysis (GSEA) was performed to analyze signaling pathways enriched for DEGs. Hub genes were identified by cytoHubba analysis in Cytoscape. Reverse transcriptase-polymerase chain reaction was used to validate SLC39A8 and its correlated metabolic DEGs expression in PH (SU5416/Hypoxia) mice.

Results

SLC39A8 expression was downregulated in PH patients, and this expression pattern was validated in PH (SU5416/Hypoxia) mouse lung tissue. SLC39A8-correlated genes were mainly enriched in the metabolic pathways. Within these SLC39A8-correlated genes, 202 SLC39A8-correlated metabolic genes were screened out, and seven genes were identified as SLC39A8-correlated metabolic hub genes. The expression patterns of hub genes were analyzed between PH patients and controls and further validated in PH mice. Finally, four genes (Fasn, Nsdhl, Acat2, and Acly) were downregulated in PH mice. However, there were no significant differences in the expression of the other three hub genes between PH mice and controls. Of the four genes, Fasn and Acly are key enzymes in fatty acids synthesis, Nsdhl is involved in cholesterol synthesis, and Acat2 is implicated in cholesterol metabolic transformation. Taken together, these results provide novel insight into the role of Zip8 in PH.

Impact of diabetes mellitus on disease severity and patient survival in idiopathic pulmonary arterial hypertension: data from the Polish multicentre registry (BNP-PL)

BACKGROUND

Recent studies revealed that alterations in glucose and lipid metabolism in idiopathic pulmonary arterial hypertension (IPAH) are associated with disease severity and poor survival. However, data regarding the impact of diabetes mellitus (DM) on the prognosis of patients with IPAH remain scarce. The aim of our study was to determine that impact using data from a national multicentre prospective pulmonary hypertension registry.

METHODS

We analysed data of adult patients with IPAH from the Database of Pulmonary Hypertension in the Polish population (BNP‑PL) between March 1, 2018 and August 31, 2020. Upon admission, clinical, echocardiographic, and haemodynamic data were collected at 21 Polish IPAH reference centres. The all-cause mortality was assessed during a 30-month follow-up period. To adjust for differences in age, body mass index (BMI), and comorbidities between patients with and without DM, a 2-group propensity score matching was performed using a 1:1 pairing algorithm.

RESULTS

A total of 532 patients with IPAH were included in the study and 25.6% were diagnosed with DM. Further matched analysis was performed in 136 patients with DM and 136 without DM. DM was associated with older age, higher BMI, more advanced exertional dyspnea, increased levels of N-terminal pro-brain natriuretic peptide, larger right atrial area, increased mean right atrial pressure, mean pulmonary artery pressure, pulmonary vascular resistance, and all-cause mortality compared with no DM.

CONCLUSIONS

Patients with IPAH and DM present with more advanced pulmonary vascular disease and worse survival than counterparts without DM independently of age, BMI, and cardiovascular comorbidities.

Cardiometabolic Risk Factors Associated With Right Ventricular Function and Compensation in Patients Referred for Echocardiography

Background Pulmonary hypertension and right ventricular (RV) dysfunction are drivers of adverse outcomes; however, modifiable risk factors for RV dysfunction are not well described. We investigated the association between clinical markers of metabolic syndrome and echocardiographic RV function in a large referral population. Methods and Results Using electronic health record data, we performed a retrospective cohort study of patients aged ≥18 years referred for transthoracic echocardiography between 2010 and 2020 with RV systolic pressure (RVSP) or tricuspid annular plane systolic excursion (TAPSE) values. Pulmonary hypertension was defined by RVSP >33 mm Hg and RV dysfunction by TAPSE ≤1.8 cm. Our sample included 37 203 patients of whom 19 495 (52%) were women, 29 752 (83%) were White, with a median age of 63 years (interquartile range, 51-73). Median (interquartile range) RVSP was 30.0 mm Hg (24.0-38.7), and median TAPSE was 2.1 cm (1.7-2.4). Within our sample, 40% had recorded RVSP >33 mm Hg, and 32% with TAPSE <1.8 cm. Increase in RVSP from normal (<33 mm Hg) to mildly elevated (33-39 mm Hg) or elevated (>39 mm Hg) was associated with lower low-density lipoprotein and high-density lipoprotein, and higher hemoglobin A1c and body mass index (P<0.001). A decrease in TAPSE between groups of TAPSE >1.8 cm, TAPSE 1.5-1.8 cm, and TAPSE <1.5 cm was associated with increased triglyceride:high-density lipoprotein ratio and hemoglobin A1c, and decreased body mass index, low-density lipoprotein, high-density lipoprotein, and systolic blood pressure (P<0.001). Most associations between cardiometabolic predictors and RVSP and TAPSE were nonlinear with clear inflection points associated with higher pulmonary pressure and lower RV function. Conclusions Clinical measures of cardiometabolic function were highly associated with echocardiographic measures of right ventricular function and pressure.

Biomarkers in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a severe medical condition characterized by elevated pulmonary vascular resistance (PVR), right ventricular (RV) failure, and death in the absence of appropriate treatment. The progression and prognosis are strictly related to the etiology, biochemical parameters, and treatment response. The gold-standard test remains right-sided heart catheterization, but dynamic monitoring of systolic pressure in the pulmonary artery is performed using echocardiography. However, simple and easily accessible non-invasive assays are also required in order to monitor this pathology. In addition, research in this area is in continuous development. In recent years, more and more biomarkers have been studied and included in clinical guidelines. These biomarkers can be categorized based on their associations with inflammation, endothelial cell dysfunction, cardiac fibrosis, oxidative stress, and metabolic disorders. Moreover, biomarkers can be easily detected in blood and urine and correlated with disease severity, playing an important role in diagnosis, prognosis, and disease progression.

Corydalis saxicola Bunting Total Alkaloids ameliorate diet-induced non-alcoholic steatohepatitis by regulating hepatic PI3K/Akt and TLR4/NF-κB pathways in mice

Corydalis saxicola Bunting (Yanhuanglian), distributed in Southwest China, is mainly used for treatment of hepatitis, oral mucosal erosion, conjunctivitis, dysentery, acute abdominal pain and hemorrhoids in the folk. Corydalis saxicola Bunting Total Alkaloids (CSBTA) are the active ingredients extracted from the root of C. saxicola bunting. Non-alcoholic steatohepatitis (NASH) is the hinge between steatosis and cirrhosis in the spectrum of Non-alcoholic fatty liver disease (NAFLD), which has become one of the most common chronic liver diseases in the world. CSBTA can reduce tumors and brain diseases through anti-inflammatory and antioxidant pathways. Our study was designed to clarify the effects of CSBTA on the HFHC (High fat and high carbohydrate drinking) diet induced mice. In our research, A HFHC diet induced NASH mice model was applied to investigate the effects of CSBTA in vivo and obeticholic acid (OA) was set as positive control. Moreover, the underlying mechanisms were explored by palmitic acid (PA) and lipopolysaccharide (LPS) stimulated HepG2 cells in vitro. The in vivo study illustrated that CSBTA could alleviate mice away from the onset of NASH, and reduce intrahepatocellular lipid accumulation and hepatocyte inflammation under high fat condition. Further in vitro analysis confirmed that CSBTA attenuated inflammation and hepatic lipid accumulation by improving hepatic PI3K/Akt and suppressing hepatic TLR4/NF-κB pathways. In summary, this study demonstrated that CSBTA might be a promising compound for the treatment of NAFLD.

Differential serum lipid distribution in IPAH and CHD-PAH patients

Lipid homeostasis is dysregulated in pulmonary arterial hypertension (PAH). A decrease in serum high- and low-density lipoprotein cholesterol (HDL-C and LDL-C) is significantly associated with the worse prognosis of PAH. However, no study has investigated the differential distribution of lipids in various PAH subtypes. We enrolled 190 patients in this retrospective study, which includes 20 patients with congenital heart disease without PAH (CHD-nonPAH), 101 patients with PAH associated with congenital heart disease (CHD-PAH), 69 patients with idiopathic PAH (IPAH) and 81 healthy controls. Laboratory parameters such as liver and renal function, serum lipids, C-reactive protein, N-terminal pro-brain natriuretic peptide (NT-proBNP), echocardiography, right heart catheterization and 6-min walk distance (6MWD) were performed. All types of cholesterol including HDL-C, LDL-C and total cholesterol (CHOL) were significantly lower in IPAH patients in association with right heart function. Although LDL-C and CHOL were lower in CHD-PAH, they were not associated with disease severity or heart failure. Thus, we conclude that IPAH and CHD-PAH patients exhibited a differential distribution pattern of serum lipids.

A Novel Clinical Five-Risk Factor Panel for Individualized Recurrence Risk Assessment of Patients With Acute Anterior Uveitis

Purpose

Detecting and managing relapses of acute anterior uveitis (AAU) is necessary for improving follow-up planning to minimize recurrences and further complications. However, reliable clinical and laboratory risk factors are lacking, as is a predictive model for use in clinical practice that is capable of identifying patients at high risk for recurrence after remission.

Methods

We analyzed 38 laboratory parameters and clinical data from a large longitudinal retrospective cohort of 233 patients with AAU. Association of laboratory parameters with recurrence-free survival (RFS) was evaluated using univariate Cox proportional hazards regression. A clinically applicable predictive model was developed using a logistic regression model.

Results

Of the 38 laboratory parameters studied, we identified 5 parameters (HDL, ankylosing spondylitis, HLA-B27, MO, and LDL) to be associated with RFS. We developed a clinical five-risk factor panel (5RF-panel), which was capable of effectively distinguishing recurrent patients from nonrelapsed patients (area under the curve [AUC] = 0.837), as well as between patients with high and low risks of AAU recurrence (hazard ratio [HR] = 45.874, 95% confidence interval [CI] = 5.232-402.2, P < 0.001). The robust performance of the 5RF-panel was further validated in the testing cohort (AUC = 0.725, and HR = 51.982, 95% CI = 4.438-608.9, P = 0.024). Furthermore, the 5RF-panel demonstrated superior performance in stratifying recurrence risk based on known risk factors.

Conclusions

We identified and validated a novel clinical 5RF-panel to predict individualized risk of AAU recurrence and improved patient classification for clinical management.

Translational Relevance

The present study identified and validated a 5RF-panel that is a promising individualized predictive tool to monitor recurrence risk and guide personalized management of patients with AAU.

Associations Between Peripheral Blood Microbiome and the Risk of Hypertension

BACKGROUND

Although previous studies have reported the gut microbiome is closely related to hypertension development, whether the change in blood microbiome is associated with the risk of hypertension remains unclear.

METHODS

One hundred and fifty incident hypertension cases and 150 age (± 2 years) and gender (1:1) matched nonhypertension controls included in this nested case-control study were recruited from a prospective cohort study of "135." The composition of the blood microbiome was characterized using bacterial 16S ribosomal RNA gene sequencing. The relative abundance of detected bacteria was converted to a negative logarithm of 10 for the statistical analysis.

RESULTS

Totally, 10,689,961 high-quality sequences were acquired. The Chao1 index of the blood microbiome in nonhypertension controls was significantly higher than in hypertensive group (2,302.08 ± 752.78 vs. 1,598.21 ± 500.88, P < 0.001). Compared with the nonhypertension controls, the relative abundance of Proteobacteria phylum was significantly increased (P < 0.001), whereas the relative abundance of phyla Firmicutes and Bacteroidetes were significantly reduced in the hypertensive cases (P < 0.001 and P = 0.039, respectively). At genus level, the risk of hypertension was directly associated with the relative abundance of Acinetobacter (odds ratio [OR]: 1.43, 95% confidence interval [CI]: 1.01-2.03), Sphingomonas (OR: 1.84, 95% CI: 1.32-2.56), and Staphylococcus (OR: 0.51, 95% CI: 0.36-0.73), respectively. In addition, the relative abundance of Pseudomonas was minor positively correlated with the total cholesterol level. However, the relative Staphylococcus level was minor positively correlated with high-density lipoprotein cholesterol level.

CONCLUSIONS

The composition of the blood microbiome is significantly associated with the development of hypertension.

High-fat diet attenuates the improvement of hypoxia-induced pulmonary hypertension in mice during reoxygenation

BACKGROUND

It is widely recognized that metabolic disorder is associated with pulmonary hypertension (PH). It is known that hypoxia-induced elevated pulmonary artery pressure in mice returns to normal pressure during reoxygenation. However, it is still unclear how metabolic disorder affects the reverse remodeling of pulmonary arteries. In this study, we investigated the effects of high-fat diet (HFD) on the decrease in pulmonary artery pressure and reverse remodeling of pulmonary arteries in mice with hypoxia-induced PH.

METHODS

We used female C57BL/6 mice aged 8 weeks. After being exposed to hypoxia (10% oxygen for four weeks) to induce PH, the mice were returned to normoxic conditions and randomized into a normal diet (ND) group and HFD group. Both groups were fed with their respective diets for 12 weeks.

RESULTS

The Fulton index and right ventricular systolic pressure measured by a micro-manometer catheter were significantly higher in the HFD group than in the ND group at 12 weeks after reoxygenation. The medial smooth muscle area was larger in the HFD group. Caspase-3 activity in the lung tissue of the HFD group was decreased, and the apoptosis of pulmonary smooth muscle cells was suppressed after reoxygenation. Moreover, the expression levels of peroxisome proliferator-activated receptor-γ and apelin were lower in the HFD group than in the ND group.

CONCLUSIONS

The results suggest that metabolic disorder may suppress pulmonary artery reverse remodeling in mice with hypoxia-induced PH during reoxygenation.

Vascular Metabolic Mechanisms of Pulmonary Hypertension

Pulmonary hypertension (PH) is a severe and progressive disease characterized by increased pulmonary vascular resistance leading to right heart failure and death. In PH, the cellular metabolisms including those of the three major nutrients (carbohydrate, lipid and protein) are aberrant in pulmonary vascular cells. Glucose uptake, glycolysis, insulin resistance, sphingolipid S1P, PGE₂, TXA₂, leukotrienes and glutaminolysis are upregulated, and phospholipid-prostacyclin and L-arginine-nitric oxide pathway are compromised in lung vascular cells. Fatty acid metabolism is disordered in lung endothelial cells and smooth muscle cells. These molecular mechanisms are integrated to promote PH-specific abnormal vascular cell proliferation and vascular remodeling. This review summarizes the recent advances in the metabolic reprogramming of glucose, fatty acid, and amino acid metabolism in pulmonary vascular remodeling in PH and the mechanisms for how these alterations affect vascular cell fate and impact the course of PH.

Expression of ApoA5 and its function in the right ventricular failing and remodeling secondary to pulmonary hypertension

Right heart failure and right ventricular (RV) remodeling were the main reason for mortality of pulmonary hypertension (PH) patients. Apolipoprotein AV (ApoA5) is a key regulator of plasma triglyceride and have multifunction in several target organs. We detected decreased ApoA5 in serum of patients with PH and both in serum and RV of monocrotaline-induced PH model. Exogenously, overexpression ApoA5 by adenovirus showed protective effects on RV failure and RV fibrosis secondary to PH. In addition, in vitro experiments showed ApoA5 attenuated the activation of fibroblast induced by transforming growth factor β1 and synthesis and secretion of extracellular matrix by inhibiting focal adhesion kinase-c-Jun N-terminal kinase-Smad3 pathway. Finally, we suggest that ApoA5 may potentially be a pivotal target for RV failure and fibrosis secondary of PH.

Apolipoprotein A-I Supports MSCs Survival under Stress Conditions

Clinical trials have shown the safety of mesenchymal stem/stromal cells (MSCs) transplantation, but the effectiveness of these treatments is limited. Since, transplanted MSCs will undergo metabolic disturbances in the bloodstream, we investigated the influence of blood plasmas of type 2 diabetes (T2D) patients on MSCs viability and examined whether apolipoprotein A-I (apoA-I) could protect cells from stressful conditions of serum deprivation (SD), hypoxia, and elevated concentrations of reactive oxygen species (ROS). ApoA-I exhibits anti-inflammatory, immune activities, improves glycemic control, and is suitable for T2D patients but its influence on MSCs remains unknown. For the first time we have shown that apoA-I decreases intracellular ROS and supports proliferative rate of MSCs, thereby increasing cell count in oxidation conditions. ApoA-I did not influence cell cycle when MSCs were predominantly in the G0/G1 phases under conditions of SD/hypoxia, activated proliferation rapidly, and reduced apoptosis during MSCs transition to the oxygenation or oxidation conditions. Finally, it was found that the blood plasma of T2D individuals had a cytotoxic effect on MSCs in 39% of cases and had a wide variability of antioxidant properties. ApoA-I protects cells under all adverse conditions and can increase the efficiency of MSCs transplantation in T2D patients.

Characterization of Patients with Pulmonary Arterial Hypertension: Data from the Polish Registry of Pulmonary Hypertension (BNP-PL)

Current knowledge of pulmonary arterial hypertension (PAH) epidemiology is based mainly on data from Western populations, and therefore we aimed to characterize a large group of Caucasian PAH adults of Central-Eastern European origin. We analyzed data of incident and prevalent PAH adults enrolled in a prospective national registry involving all Polish PAH centers. The estimated prevalence and annual incidence of PAH were 30.8/mln adults and 5.2/mln adults, respectively and they were the highest in females ≥65 years old. The most frequent type of PAH was idiopathic (n = 444; 46%) followed by PAH associated with congenital heart diseases (CHD-PAH, n = 356; 36.7%), and PAH associated with connective tissue disease (CTD-PAH, n = 132; 13.6%). At enrollment, most incident cases (71.9%) were at intermediate mortality risk and the prevalent cases had most of their risk factors in the intermediate or high risk range. The use of triple combination therapy was rare (4.7%). A high prevalence of PAH among older population confirms the changing demographics of PAH found in the Western countries. In contrast, we found: a female predominance across all age groups, a high proportion of patients with CHD-PAH as compared to patients with CTD-PAH and a low use of triple combination therapy.

Cross-Talk between Lipoproteins and Inflammation: The Role of Microvesicles

Atherothrombosis is the principal underlying cause of cardiovascular disease (CVD). Microvesicles (MV) are small blebs originated by an outward budding at the cell plasma membranes, which are released in normal conditions. However, MV release is increased in pathophysiologic conditions such as CVD. Low density lipoprotein (LDL) and MV contribute to atherothrombosis onset and progression by promoting inflammation and leukocyte recruitment to injured endothelium, as well as by increasing thrombosis and plaque vulnerability. Moreover, (oxidized)LDL induces MV release and vice-versa, perpetuating endothelium injury leading to CVD progression. Therefore, MV and lipoproteins exhibit common features, which should be considered in the interpretation of their respective roles in the pathophysiology of CVD. Understanding the pathways implicated in this process will aid in developing novel therapeutic approaches against atherothrombosis.