Different heart failure phenotypes of valvular heart disease: the role of mitochondrial dysfunction.

Valvular heart disease (VHD)-related heart failure (HF) is a special subtype of HF with an increasingly concerned heterogeneity in pathophysiology, clinical phenotypes, and outcomes. The mechanism of VHD-related HF involves not only mechanical damage to the valve itself but also valve lesions caused by myocardial ischemia. The interactions between them will lead to the occurrence and development of VHD-related HF subtypes. Due to the spatial (combination of different valvular lesions) and temporal effects (sequence of valvular lesions) of valvular damages, it can make the patient's condition more complicated and also make the physicians deal with a dilemma when deciding on a treatment plan. This indicates that there is still lack of deep understanding on the pathogenic mechanism of VHD-related HF subtypes. On the other hand, mitochondrial dysfunction (MitD) is not only associated with the development of numerous cardiac diseases such as atherosclerosis, hypertension, diabetes, and HF but also occurs in VHD. However, the role of MitD in VHD-related HF is still not fully recognized. In this comprehensive review, we aim to discuss the current findings and challenges of different valvular damages derived from HF subtypes as well as the role of MitD in VHD-related HF subtypes.

Association of KATP Variants With CMD and RAP in CAD Patients With Increased Serum Lipoprotein(a) Levels.

CONTEXT: Refractory angina pectoris (RAP) is a specific subtype of coronary artery disease (CAD). Lipoprotein(a) [Lp(a)] and its induced coronary microvascular dysfunction (CMD) play an important role in pathogenesis of RAP, but its metabolism was mostly genetically determined. The adenosine triphosphate (ATP)-sensitive potassium channel (KATP) is involved in lipid metabolism and microvascular homeostasis and becomes a promising target for the management of Lp(a) and its related RAP. OBJECTIVE: To investigate associations of KATP variants with hyperlipoprotein(a)emia, CMD, and RAP in patients with CAD. DESIGN, PATIENTS, SETTINGS: A total of 1148 newly diagnosed patients with CAD were prospectively selected and divided into control (Lp(a) < 180 mg/dL) and case (Lp(a) ≥ 180 mg/dL, hyperlipoprotein(a)emia) group. METHODS: 9 KATP variants were genotyped by MassARRAY system. The expression profile of exosome-derived microRNAs (exo-miRs) was identified by next-generation sequencing, and the expression levels of differentially expressed exo-miRs were evaluated by quantitative RT-PCR in verification cohort. RESULTS: Three KATP variants were associated with increased risk of hyperlipoprotein(a)emia in patients with CAD as follows: rs2285676 (AA + GA genotype, adjusted odds ratio [OR] = 1.44; 95% CI, 1.10-1.88; P = 0.008), rs1799858 (CC genotype, adjusted OR = 1.33; 95% CI, 1.03-1.73; P = 0.030), and rs141294036 (CC genotype, adjusted OR = 1.43; 95% CI, 1.10-1.87; P = 0.008). Only rs141294036 was associated with increased risk of CMD (CC genotype, adjusted OR = 1.62; 95% CI, 1.23-2.13; P = 0.001), and further with increased RAP risk (CC genotype, adjusted hazard ratio = 2.05; 95% CI, 1.22-3.43; P = 0.007) after median follow-up of 50.6 months. Between the 2 genotypes of rs141294036, 152 exo-miRs were significantly differentially expressed, but only 10 exo-miRs (miR-7110-3p, miR-548az-5p, miR-214-3p, let-7i-5p, miR-218-5p, miR-128-3p, miR-378i, miR-625-3p, miR-128-1-5p, and miR-3187-3p) were further confirmed in patients with RAP with hyperlipoprotein(a)emia and CMD. CONCLUSION: KATP rs141294036 may serve a potential genetic marker for hyperlipoprotein(a)emia, CMD, and RAP in patients with CAD.

Associations of ATP-Sensitive Potassium Channel's Gene Polymorphisms With Type 2 Diabetes and Related Cardiovascular Phenotypes.

Type 2 diabetes (T2D) is characterized by increased levels of blood glucose but is increasingly recognized as a heterogeneous disease, especially its multiple discrete cardiovascular phenotypes. Genetic variations play key roles in the heterogeneity of diabetic cardiovascular phenotypes. This study investigates possible associations of ATP-sensitive potassium channel (KATP) variants with cardiovascular phenotypes among the Chinese patients with T2D. Six hundred thirty-six patients with T2D and 634 non-diabetic individuals were analyzed in the study. Nine KATP variants were determined by MassARRAY. The KATP rs2285676 (AA + GA, OR = 1.43, 95% CI: 1.13-1.81, P = 0.003), rs1799858 (CC, OR = 1.42, 95% CI: 1.12-1.78, P = 0.004), and rs141294036 (CC, OR = 1.45, 95% CI: 1.15-1.83, P = 0.002) are associated with increased T2D risk. A follow-up of at least 45.8-months (median) indicates further association between the 3 variants and risks of diabetic-related cardiovascular conditions. The associations are categorized as follows: new-onset/recurrent acute coronary syndrome (ACS) (rs2285676/AA + GA, HR = 1.37, 95% CI: 1.10-1.70, P = 0.005; rs141294036/TT + CT, HR = 1.59, 95% CI: 1.28-1.99, P < 0.001), new-onset stroke (rs1799858/CC, HR = 2.58, 95% CI: 1.22-5.43, P = 0.013; rs141294036/CC, HR = 2.30, 95% CI: 1.16-4.55, P = 0.017), new-onset of heart failure (HF) (rs1799858/TT + CT, HR = 2.78, 95% CI: 2.07-3.74, P < 0.001; rs141294036/TT + CT, HR = 1.45, 95% CI: 1.07-1.96, P = 0.015), and new-onset atrial fibrillation (AF) (rs1799858/TT + CT, HR = 2.05, 95% CI: 1.25-3.37, P = 0.004; rs141294036/CC, HR = 2.31, 95% CI: 1.40-3.82, P = 0.001). In particular, the CC genotype of rs1799858 (OR = 2.38, 95% CI: 1.11-5.10, P = 0.025) and rs141294036 (OR = 1.95, 95% CI: 1.04-3.66, P = 0.037) are only associated with the risk of ischemic stroke while its counterpart genotype (TT + CT) is associated with the risks of HF with preserved ejection fraction (HFpEF) (rs1799858, OR = 3.46, 95% CI: 2.31-5.18, P < 0.001) and HF with mildly reduced ejection fraction (HFmrEF) (rs141294036, OR = 2.74, 95% CI: 1.05-7.15, P = 0.039). Furthermore, the 3 variants are associated with increased risks of abnormal serum levels of triglyceride (TIRG) (≥ 1.70 mmol/L), low-density lipoprotein cholesterol (LDL-C) (≥ 1.40 mmol/L), apolipoprotein B (ApoB) (≥ 80 mg/dL), apolipoprotein A-I (ApoA-I) level (< 120 mg/dL), lipoprotein(a) Lp(a) (≥ 300 mg/dL) and high-sensitivity C-reactive protein (HsCRP) (≥ 3.0 mg/L) but exhibited heterogeneity (all P < 0.05). The KATP rs2285676, rs1799858, and rs141294036 are associated with increased risks of T2D and its related cardiovascular phenotypes (ACS, stroke, HF, and AF), but show heterogeneity. The 3 KATP variants may be promising markers for diabetic cardiovascular events favoring "genotype-phenotype" oriented prevention and treatment strategies.

Association of Digoxin Application Approaches With Long-Term Clinical Outcomes in Rheumatic Heart Disease Patients With Heart Failure: A Retrospective Study.

Objective: This retrospective, case-control study was executed to assess the effects of digoxin (DGX) use approaches [continuous use of DGX (cDGX) vs. intermittent use of DGX (iDGX)] on the long-term prognosis in rheumatic heart disease (RHD) patients with heart failure (HF). Methods: A total of 642 RHD patients were enrolled to this study after propensity matching. The associations of DGX application approaches with the risks of all-cause mortality, cardiovascular death (CVD), HF re-hospitalization (1-, 3-, and 5-year), and new-onset atrial fibrillation (AF) were analyzed by multivariate Cox proportional hazards or binary logistic regression models, respectively. Results: cDGX was associated with increased risks of all-cause mortality (adjusted HR = 1.84, 95% CI: 1.27-2.65, P = 0.001) and CVD (adjusted HR = 2.23, 95% CI: 1.29-3.83, P = 0.004) in RHD patients with HF compared to iDGX. With exception of 1-year HF re-hospitalization risk, cDGX was associated with increased HF re-hospitalization risk of 3-year (adjusted OR = 1.53, 95% CI: 1.03-2.29, P = 0.037) and 5-year (adjusted OR = 1.61, 95% CI: 1.05-2.50, P = 0.031) as well as new-onset AF (adjusted OR = 2.06, 95% CI: 1.09-3.90, P = 0.027). Conclusion: cDGX was significantly associated with increased risks of all-cause mortality, CVD, medium-/long-term HF re-hospitalization, and new-onset AF in RHD patients with HF.

Clinical and Genetic Analysis of KATP Variants With Heart Failure Risk in Patients With Decreased Serum ApoA-I Levels.

CONTEXT: Lower serum concentration of apolipoprotein A-I (ApoA-I) is causally associated with heart failure (HF) risk. Adenosine triphosphate-sensitive potassium channels (KATP), as gating channels coupling vascular reactivity and metabolism with ischemic protection, become a new potential target of management for HF. The KATP gene sequence is highly polymorphic and has a high degree of genetic heterogeneity. OBJECTIVE: This work aimed to determine whether KATP variants predict the risks of decreased ApoA-I concentration and its related HF. METHODS: A total of 634 individuals, including 317 patients with decreased ApoA-I concentration (< 120 mg/dL) and 317 counterpart participants (≥ 120 mg/dL), were retrospectively selected. Five KATP variants were genotyped through the MassARRAY platform. Exosome-derived microRNAs (exo-miRs) expression profiles were identified by next-generation sequencing, and the top 10 differentially expressed (DE) exo-miRs were verified using quantitative polymerase chain reaction in a validation cohort of 240 individuals with decreased ApoA-I concentration. RESULTS: KATP rs141294036 was related to an increased risk of lower ApoA-I levels (adjusted odds ratio [OR] = 1.95, P = .002) and HF incidence (adjusted OR = 2.38, P = .009), especially heart failure with preserved ejection fraction (HFpEF; adjusted OR = 2.13, P = .015). After a median 48.6-month follow-up, participants carrying the CC genotype of rs141294036 were associated with an elevated HF rehospitalization risk (adjusted hazard ratio = 1.91, P = .005). Thirty-six exo-miRs were significantly DE between different genotypes of rs141294036 in participants with lower ApoA-I levels, but only 5 exo-miRs (miR-31-5p, miR-126-5p, miR-106a-5p, miR-378i, and miR-181c-5p) were further confirmed. CONCLUSION: KATP rs141294036 was associated with increased risks of lower ApoA-I levels, HF incidence (especially HFpEF), and HF rehospitalization in those with the 5 confirmed exo-miRs and its related metabolic pathways.

Association of ACE2 variant rs4646188 with the risks of atrial fibrillation and cardioembolic stroke in Uygur patients with type 2 diabetes.

BACKGROUND: Atrial fibrillation (AF) is the most common cardiac arrhythmia. Type 2 diabetes (T2D) is an independent risk factor for AF. The cardioembolic stroke (CS) risk is increased when both conditions coexist. Whether angiotensin-converting enzyme 2 (ACE2) genetic variants predict increased risks AF and CS in Uygur patients with T2D remain elusive. METHODS: A total of 547 Uygur subjects (272 controls and 275 T2D patients) were recruited to the study from south Xinjiang. Eight ACE2 variants were identified by MassARRAY system. RESULTS: ACE2 rs2074192 (CC, adjusted RR = 2.55, 95% CI 1.35-4.80, P = 0.004), rs4240157 (CC + CT, adjusted RR = 2.26, 95% CI 1.27-4.04, P = 0.006) and rs4646188 (TT, adjusted RR = 2.37, 95% CI 1.16-4.86, P = 0.018) were associated with higher AF risk. ACE2 rs4240157 (CC + CT, adjusted RR = 2.68, 95% CI 1.36-5.27, P = 0.004) and rs4646188 (TT, adjusted RR = 2.56, 95% CI 1.06-6.20, P = 0.037) were further associated with higher CS risk. The 3 ACE2 variants were related to larger left atrial end-systolic diameter (LAD) (all P < 0.05), but not all of the 3 ACE2 variants were related to increased levels of serum sodium (rs4240157 and rs4646188, all P < 0.05), HsCRP (rs4240157 and rs4646188, all P < 0.05) as well as decreased serum potassium levels (rs2074192 and rs4646188, all P < 0.05). The 3 ACE2 variants exhibited heterogeneity on circulating RAAS activation. In particular, ACE2 rs4646188 was associated with higher levels of ACE (P = 0.017 and 0.037), Ang I (P = 0.002 and 0.001), Ang II (both P < 0.001) and ALD (P = 0.005 and 0.011). CONCLUSION: These results indicated ACE2 rs4646188 was associated with increased risk of AF and CS among diabetic patients in Uygurs, which could be a promising genetic predisposition marker for early and personalized prevention strategies for the aforementioned clinical pathologies.

Effects of Triple-Mutated Hypoxia-Inducible Factor-1α on Angiogenesis and Cardiac Function Improvement in Rats with Myocardial Infarction.

BACKGROUND/AIMS: The effects of hypoxia-inducible factor-1α (HIF-1α) on angiogenesis and cardiac function improvement in rats with myocardial infarction (MI) is unknown and our current study was to evaluate whether HIF-1α would be beneficial for angiogenesis and cardiac function improvement in MI rats. METHODS: A mutant of adenovirus HIF-1α (Ad-HIF-1α-Trip) was constructed by three sites mutation (Pro402, Pro564 and Asn803) in HIF-1α. The rat MI model was produced by permanent ligation of left anterior descending artery and 1×109 PFU adenovirus (Ad) vector particles of Ad-Null, Ad- HIF-1a-564/402, Ad- HIF-1a-Trip, 250ng vascular endothelial growth factor (VEGF) in 0.5ml saline or only 0.5 ml saline were injected intramuscularly around the infarct border zone. Real-time PCR, ELISA and western blotting were used to evaluate angiogenesis factors expression. Capillary density and necrotic areas were detected by immunohistochemistry staining and TTC staining, respectively. Cardiac function assessment was done by echocardiography before operation and on day 7, 14 and 28 after MI. Blood samples were drawn for the measurement of cardiac biomarkers, liver function and kidney function. RESULTS: On day 7, compared to the other groups, the expressions of HIF-1α and angiogenesis factors, and the capillary density were all significantly higher in the Ad-HIF-1α-Trip group. However, on day 28, no significant between-group differences were observed. After 72 hours of MI, serum level of cardiac biomarkers and the necrotic areas were significantly lower in the Ad-HIF-1a-Trip group compared to the other groups. Echocardiography showed that on day 7, cardiac functions were significantly reduced in all groups compared to the baseline. Cardiac function in the Ad-HIF-1α-Trip group was decreased less profoundly through day 7 to day 28 compared to the other groups. Importantly, no significant differences in liver and renal function were observed. CONCLUSION: Mutation of Pro402, Pro564 and Asn803 are beneficial for enhancement of the efficacy of HIF-1α. Ad-HIF-1α-Trip is able to improve angiogenesis and cardiac function, which may be a promising avenue for treatment of ischemic heart disease in the future.

[Effects of a triple mutant hypoxia-inducible factor-1α on proliferation and vascular endothelial growth factor expression in human microvascular endothelial cells].

OBJECTIVE: To investigate the effects of a recombinant adenovirus-mediated triple mutant hypoxia-inducible factor-1α (HIF-1α) on the proliferation and vascular endothelial growth factor (VEGF) expression in human microvascular endothelial cells (hMVECs). METHODS: The adenovirus vector of the triple mutant HIF-1α (Ad-HIF-1α(564/402/803)), adenovirus vector of wild-type HIF-1α (Ad-HIF-1α(nature)), Ad-lacZ and Ad-Null were amplified in HEK293A cells, and the adenoviruses were purified and titrated. Dual luciferase reporter assay system was employed to detect the transcriptional activities of wild-type and triple mutant HIF-1α. After infection of the hMVECs with the adenoviruses, the cellular protein expressions of HIF-1α and VEGF were detected using Western blotting, and the cell proliferation was assessed by MTS assay. RESULTS: The transcriptional activity of the triple mutant HIF-1α was significantly higher than that of wildtype HIF-1α in the infected hMVECs (P<0.001). The protein levels of HIF-1α and VEGF in cells infected with Ad-HIF-1α(564/402/803) were significantly higher than those in cells infected with other adenoviruses, and HIF-1α dose-dependently up-regulated VEGF protein expression. The absorbance was significantly higher in Ad-HIF-1α(564/402/803) group than in the other groups (P<0.01) on the third and fifth days after infection. CONCLUSION: The recombinant adenovirus-mediated triple mutant HIF-1α expression is stable under normoxic condition. The triple mutant HIF-1α can up-regulate the expression of VEGF protein in hMVECs to promote the cell proliferation.

Mutant hypoxia inducible factor-1α improves angiogenesis and tissue perfusion in ischemic rabbit skeletal muscle.

Hypoxia-inducible factor-1α (HIF-1α) is one of the most potent angiogenic growth factors. It regulates genes involved in angiogenesis, but is inactivated rapidly by normoxia. Ad-HIF-1α-Trip was constructed by transforming Pro402, Pro564, and Asn803 in HIF-1α to alanine in order to delay degradation and create a constitutive transcriptional activator. In this study, we investigated whether Ad-HIF-1α-Trip could induce functional mature angiogenesis and the possible mechanisms involved. We found that Ad-HIF-1α-Trip increased the expression of multiple angiogenic genes in cultured HMVEC-Ls, including VEGF, PLGF, PAI-1, and PDGF. In a rabbit model of acute hind limb ischemia, Ad-HIF-1α-Trip improved tissue perfusion and collateral vessels, as measured by contrast-enhanced ultrasound (CEU), CT angiography, and vascular casting. Ad-HIF-1α-Trip also produced more histologically identifiable capillaries, which were verified by immunostaining, compared with controls. Interestingly, inhibition of CBP/p300 by curcumin prevented HIF-1α from inducing the expression of several angiogenic genes. The present study suggests that Ad-HIF-1α-Trip can induce mature angiogenesis and improve tissue perfusion in ischemic rabbit skeletal muscle. CBP/p300, which interacts with the transactivation domains of HIF-1α, is important for HIF-1α-induced transcription of angiogenic genes.

[Effects of recombinant adenovirus-mediated triple mutant of hypoxia inducible factor-1alpha in modulating angiogenesis].

OBJECTIVE: To investigate the effect of recombinant adenovirus-mediated triple mutant of hypoxia inducible factor-1alpha (Ad-HIF-1alpha-564/402/803) in modulating angiogenesis in vitro. METHODS: The recombinant adenoviruses Ad-lacZ, Ad-Null, Ad-HIF-1alpha-nature, and Ad-HIF-1alpha-564/402/803 were amplified in HEK293A cells and purified by ultracentrifugation in CsCl step gradient solutions, and the adenoviral titer was determined by end-point dilution assay. The recombinant adenovirus was confirmed by PCR and DNA sequence analysis, and the infection efficiency was observed by X-gal staining. Human microvascular endothelial cells (HMVECs) were infected with Ad- HIF-1alpha-564/402/803, Ad- HIF-1alpha-nature, or Ad-Null to compare the number of capillary-like tube structures in vitro. The effect of Ad- HIF-1alpha-564/402/803, Ad-HIF-1alpha-nature, and Ad-Null on angiogenesis was evaluated using a chick embryo chorioallantoic membrane (CAM) model. RESULTS: PCR and gene sequencing suggested the correct construction of the recombinant adenovirus HIF-1alpha, and the adenoviral titer reached 1011-1012 PFU/ml. Infection of the hMVECs with Ad-HIF-1alpha-564/402/803 at the optimal multiplicity of infection of 100 pfu/cell resulted in a significantly greater number of capillary-like tube structures than infection by Ad-HIF-1alpha-nature and Ad-Null (P=0.000). Ad-HIF-1alpha-564/402/803 group showed significantly higher microvessel density than Ad-HIF-1alpha-nature, Ad-Null, and PBS groups, with also higher angiogenesis area to CAM area ratio (P=0.01, 0.000, and 0.000, respectively). CONCLUSION: The triple mutant Ad-HIF-1alpha-564/402/803 can obviously promote the formation of capillary-like tube structures in vitro and modulate angiogenesis in the CAM model, suggesting the capacity of Ad-HIF-1alpha-564/402/803 in promoting angiogenesis under normoxic condition.

[Effect of different doses of recombinant adenovirus mediated hypoxia-inducible factor-1alpha on angiogenesis in ischemic lower hind limb of rabbits].

OBJECTIVE: To investigate the effect of recombinant adenovirus-mediated hypoxia-inducible factor-1alpha (Ad-HIF-1alpha) at different doses on angiogenesis in a rabbit model of hind limb ischemia. METHODS: Left hind limb ischemia was induced in 45 Zealand white rabbits by ligation of the left femoral artery. The rabbits were randomly divided into 5 groups (n=9) to receive intramuscular injections of 0.5 ml saline, 2x10(10) PFU empty vector (Ad-null), or different doses of Ad-HIF-1alpha (2x10(9), 2x10(10) or 2x10(11) PFU) immediately after the operation. On the 7th day after the operation, real-time PCR was used to detect the expression of HIF-1alpha mRNA in the skeletal muscles. Immediately and on the 14th and 28th days after the operation, contrast enhanced ultrasound (CEU) was used to observe the blood perfusion of the hind limb. On the 28th day postoperatively, immunohistochemistry for CD31 was performed to evaluate the microvascular density (MVD). RESULTS: Real-time PCR showed that Ad-HIF-1alpha significantly increased the expression of HIF-1alpha mRNA (P<0.01) in a dose-dependent manner as compared with that in the saline and Ad-null groups (P<0.01). CEU revealed greater blood perfusion in the hind limb of rabbits in association with increased dose of Ad-HIF-1alpha (P<0.05 or P<0.01); similar changes in the MVD was observed following Ad-HIF-1alpha injections as shown by immunohistochemistry (P<0.05 or P<0.01). No significant differences were found either in the blood perfusion or MVD between saline and Ad-null groups (P>0.05). CONCLUSION: Ad-HIF-1alpha can dose-dependently promote the angiogenesis in the ischemic limb of rabbits.