Mitochondria-derived methylmalonic acid aggravates ischemia-reperfusion injury by activating reactive oxygen species-dependent ferroptosis.

Ferroptosis is a regulatory cell death process pivotal in myocardial ischemia-reperfusion (I/R) injury. However, the precise mechanism underlying myocardial ferroptosis remains less known. In this study, we investigated the pathophysiological mechanisms of methylmalonic acid (MMA) associated with ferroptosis activation in cardiomyocytes after I/R. We found an increase level of MMA in patients with acute myocardial injury after reperfusion and AC16 cells under hypoxia/reoxygenation (H/R) condition. MMA treatment was found to be associated with excessive oxidative stress in cardiomyocytes, leading to ferroptosis-related myocardial injury. In mice with I/R injury, MMA treatment aggravated myocardial oxidative stress and ferroptosis, which amplified the myocardial infarct size and cardiac dysfunction. Mechanistically, MMA promoted NOX2/4 expression to increase reactive oxygen species (ROS) production in cardiomyocytes, aggravating myocardial injury. Notably, the increased ROS further activated ferroptosis by inhibiting solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) expression. In addition, MMA decreased the ectopic nuclear distribution of nuclear factor E2-related factor 2 (NRF2) by increasing the interaction between NRF2 and kelch-like ECH-associated protein 1 (KEAP1). This impeded the activation of GPX4/SLC7A11, downstream of NRF2, activating ferroptosis and aggravating myocardial cell injury. Collectively, our study indicates that MMA activates oxidative stress and ROS generation, which induces ferroptosis to exacerbate cardiomyocyte injury in an I/R model. These findings may provide a new perspective for the clinical treatment of I/R injury and warrant further investigation.

Cost-related medication nonadherence in adults with COPD in the United States 2013-2020.

BACKGROUND: Cost-related medication nonadherence (CRN) is associated with poor prognosis among patients with chronic obstructive pulmonary disease (COPD), a population that requires long-term treatment for secondary prevention. In this study, we aimed to estimate the prevalence and sociodemographic characteristics of CRN in individuals with COPD in the US. METHODS: In a nationally representative survey of US adults in the National Health Interview Survey (2013-2020), we identified individuals aged ≥18 years with a self-reported history of COPD. Cross-sectional study. RESULTS: Of the 15,928 surveyed individuals, a weighted 18.56% (2.39 million) reported experiencing CRN, including 12.50% (1.61 million) missing doses, 13.30% (1.72 million) taking lower than prescribed doses, and 15.74% (2.03 million) delaying filling prescriptions to save costs. Factors including age < 65 years, female sex, low family income, lack of health insurance, and multimorbidity were associated with CRN. CONCLUSIONS: In the US, one in six adults with COPD reported CRN. The influencing factors of CRN are multifaceted and necessitating more rigorous research. Targeted interventions based on the identified influencing factors in this study are recommended to enhance medication adherence among COPD patients.

Cost-related medication nonadherence in US adults with asthma: The National Health Interview Survey, 2013-2020.

BACKGROUND: Asthma is a chronic disease that needs long-term control for secondary prevention. Health-related expenditures resulting from asthma are rising in the United States, and medication nonadherence is associated with adverse health outcomes in patients with asthma. OBJECTIVE: To estimate the prevalence and risk factors of cost-related medication nonadherence (CRN) in individuals with asthma in the United States. METHODS: We identified patients aged above or equal to 18 years with a history of asthma in nationally representative cross-sectional data, the National Health Interview Survey 2013 to 2020. Participants were considered to have experienced CRN if at any time in the 12 months they reported skipping doses, taking less medication, or delaying filling a prescription to save money. The weighted prevalence of CRN was estimated overall and by subgroups. Logistic regression was used to identify CRN-related characteristics. RESULTS: Of the 26,539 National Health Interview Survey participants with a history of asthma, 4360 (15.77%; representing 3.92 million of the US population) reported CRN, with 10.12% (weighted 2.51 million) of patients skipping doses to save money, 10.82% (weighted 2.69 million) taking less medication to save money, and 13.35% (weighted 3.31 million) delaying filling a prescription to save money. The subgroups young, women, low income, no health insurance, currently smoking, and with comorbidities had a higher prevalence of CRN. The results of this sensitivity analysis did not differ from the overall results. CONCLUSION: In the United States, 1 in 6 adults with a history of asthma is nonadherence with medications due to costs. Removing financial barriers to accessing medication can improve medication adherence in patients with asthma.

Methylmalonic acid, vitamin B12, and mortality risk in patients with preexisting coronary heart disease: a prospective cohort study.

BACKGROUND: The inconsistent relationship between Vitamin B12 (B12), methylmalonic acid (MMA, marker of B12 deficiency) and mortality was poorly understood, especially in patients with coronary heart disease (CHD). This study aims to investigate the association of serum MMA, and B12-related biomarkers (serum level, dietary intake, supplement use, and sensibility to B12) with all-cause and cardiovascular mortality in adults with CHD. METHODS: The data of this study were from a subcohort within the US National Health and Nutrition Examination Survey (NHANES). We included adults with preexisting CHD with serum MMA and B12, and dietary B12 intake measurements at recruitment. All participants were followed up until 31 December 2019. Weighted Cox proportional hazard regression was used to estimate hazard ratios (HR) and 95% CI of mortality risk. RESULTS: Overall, 1755 individuals (weighted mean [SE] age, 65.2 [0.5] years; 1047 men [weighted 58.5%]) with CHD were included, with geometric mean levels of serum MMA 182.4 nmol/L, serum B12 494.5 pg/ml, and dietary B12 intake 4.42 mg/day, and percentage of B12 supplements use 39.1%. During a median follow-up of 7.92 years, 980 patients died. Serum B12 concentration, dietary B12 intake and supplements use were not significantly associated with mortality risk (each p ≥ 0.388). In contrast, individuals in the top tertile of MMA had multivariable-adjusted HRs (95% CIs) of 1.70 (1.31-2.20) for all-cause mortality, and 2.00 (1.39-2.89) for cardiovascular mortality (both p trend < 0.001) compared to those in the bottom tertile of MMA. MMA-related mortality risk was particularly higher among participants with sufficient serum B12 (p < 0.001). CHD patients with increased levels of both MMA and B12 had a doubled mortality risk compared to those with lower MMA and B12 (p < 0.001). CONCLUSION: MMA accumulation but not serum or dietary vitamin B12 was associated with increased cardiovascular mortality risk among patients with CHD. This paradox may be related to decreased response to vitamin B12.

Hyperglycemia Promotes Liver Metastasis of Colorectal Cancer via Upregulation of Integrin αvß6.

BACKGROUND Diabetes is related to higher risk of multiple cancers. This study aimed to explore the effect and mechanism of diabetes on liver metastasis of CRC. MATERIAL AND METHODS Overall and liver metastasis-free survival in diabetic and non-diabetic CRC patients were compared by Kaplan-Meier analysis. Expression of alphavß6 was detected by immunohistochemistry in clinical specimens. Effects of hyperglycemia on alphavß6 expression in colon cancer cells were assessed by western blot, real-time PCR, and flowcytometry. Effects of hyperglycemia on migration and invasion were demonstrated by Transwell assay. Expression and activity of MMP-9 and MMP-2 were determined by real-time PCR and gelatin zymography. Liver metastatic nodules were counted and b6 expression was detected by western blot in a liver metastasis mouse model. RESULTS CRC patients with diabetes had poorer overall and liver metastasis-free survival, and diabetes was associated with higher alphavß6 expression in CRC specimens. Hyperglycemia promoted the invasion and migration of colon cancer cells, and upregulated the expression and activity of MMP-9, which were attenuated by inhibition of alphavß6. Hyperglycemia upregulated the expression of ß6 and cell surface expression of avb6, which was reduced by ERK inhibitor. The in vitro results were confirmed in vivo in the mouse model. CONCLUSIONS Our study demonstrated the enhancing effect of hyperglycemia on liver metastasis of CRC, and showed that alphavß6 was involved in this process, suggesting that control of glucose levels and inhibition of alphavß6 can reduce the risk of liver metastasis in diabetic CRC patients.

The association between glucose-related variables and plaque morphology in patients with ST-segment elevated myocardial infarction.

BACKGROUND: Plaque rupture (PR) and plaque erosion (PE) are main causes of acute myocardial infarction with different demographic and histology characteristics and need different treatment strategy. PR and PE can be identified with optical coherence tomography (OCT) accurately, but convenient and effective noninvasive markers for them are rarely found. History of diabetes mellitus (DM) was reported to be a potential predictor of PR in ST-segment elevated myocardial infarction (STEMI) patients, but the predictive value of other glucose-related variables for it is still uncertain. Present study aimed to clear the relationship between some glucose-related variables and plaque morphology in patients with STEMI. METHODS: We consecutively enrolled 872 STEMI patients and divided them into PR group (n = 616) and PE group (n = 256) based on OCT diagnostic criteria. The relationship of glucose-related variables, including random plasma glucose on admission (ARPG), glycosylated hemoglobin (HbA1c), post-PCI fasting plasma glucose (PFPG), DM history, glucose variable tendency (GVT) and the acute-to-chronic glycemic ratio (A/C), to the PR risk of STEMI patients was analyzed. The correlation between the glucose-related variables and plaque morphology was analyzed meanwhile. RESULTS: Among the glucose-related variables, ARPG and GVT were confirmed to be independent predictors for PR after adjusting for other traditional risk factors in nondiabetic patients. The higher the ARPG level, the more PR risk the STEMI patients had. And high HbA1c and APPG were demonstrated to have a weak and positive correlation with lipid constituents and stenosis degree of culprit vessel. CONCLUSIONS: Compared to HbA1c, DM history, and some other glucose-related variables, ARPG and GVT were risk factors for PR in STEMI patients, especially those without DM. And high HbA1c and ARPG were positively correlated with the development of vulnerable plaque in culprit vessels. Trial registration Present study is a retrospective one and the population came from the EROSION study of our center previously. It was approved by the Ethics Committee of the Second Affiliated Hospital of Harbin Medical University (Approval reference number, KY2017-249), and all patients provided written informed consent prior to the inclusion in the study and the investigation conformed to the principles outlined in the Declaration of Helsinki.

Proteomics Profiling Reveals Insulin-Like Growth Factor 1, Collagen Type VI α-2 Chain, and Fermitin Family Homolog 3 as Potential Biomarkers of Plaque Erosion in ST-Segment Elevated Myocardial Infarction.

BACKGROUND: Plaque erosion (PE) has been considered a secondary pathogenesis of ST-segment elevated myocardial infarction (STEMI) following plaque rupture (PR). Previous studies demonstrated that they had different demographic and histology characteristics and need different treatment strategy. But there are few non-invasive plasma biomarkers for distinguishing them. The present study aimed to identify non-invasive predictive biomarkers for PE and PR in patients with STEMI.Methods and Results:A total 108 patients were recruited and grouped into a PE group (n=36), a PR group (n=36), and an unstable angina pectoris (UAP) (n=36) group for analysis. A 9-plex tandem mass tag (TMT)-based proteomics was used to compare plasma protein profiles of PE, PR, and UAP. In total, 36 significant differential proteins (DPs) were identified among groups, 10 of which were screened out using bio-information analysis and validated with enzyme-linked immunosorbent assay (ELISA). The relationship of angiography and optical coherence tomography (OCT) imaging data and the 10 target DPs was analyzed statistically. Logistic regression showed elevated collagen type VI α-2 chain (COL6A2) and insulin-like growth factor 1 (IGF1), and decreased fermitin family homolog 3 (FERMT3), were positively associated with PE. Multivariate analysis indicated IGF1, FERMT3, and COL6A2 had independent predictive ability for PE. IGF1 was inversely correlated with lumen stenosis and the lipid arc of the plaque. CONCLUSIONS: IGF1, COL6A2, and FERMT3 are potential predictive biomarkers of PE in STEMI patients. And IGF1 was negatively correlated with the developing of culprit plaque.

Cardiac-specific Mst1 deficiency inhibits ROS-mediated JNK signalling to alleviate Ang II-induced cardiomyocyte apoptosis.

Apoptosis is associated with various myocardial diseases. Angiotensin II (Ang II) plays a central role in the pathogenesis of RAAS-triggered cardiac apoptosis. Our previous studies showed that mammalian Ste20-like kinase 1 (Mst1) aggravates cardiac dysfunction in cardiomyocyte under pathological conditions, but its role in Ang II-mediated cardiomyocyte apoptosis is not known. We addressed this in the present study by investigating whether cardiac-specific Mst1 knockout can alleviate Ang II-induced cardiomyocyte apoptosis along with the underlying mechanisms. In vitro and in vivo experiments showed that Ang II increased intracellular reactive oxygen species (ROS) production and cardiomyocyte apoptosis; these were reversed by administration of the ROS scavenger N-acetylcysteine and by Mst1 deficiency, which suppressed c-Jun N-terminal kinase (JNK) phosphorylation and downstream signaling. Interestingly, Mst1 knockout failed to alleviate Ang II-induced phosphorylation of extracellular signal-regulated kinase 1/2, and inactivated apoptosis signal-regulating kinase1 (ASK1) by promoting its association with thioredoxin (Trx), which reversed the Ang II-induced activation of the ASK1-JNK pathway and suppressed Ang II-induced cardiomyocyte apoptosis. Thus, cardiac-specific Mst1 knockout inhibits ROS-mediated JNK signalling to block Ang II-induced cardiomyocyte apoptosis, suggesting Mst1 as a potential therapeutic target for treatment of RAAS-activated heart failure.

Mst1 knockout enhances cardiomyocyte autophagic flux to alleviate angiotensin II-induced cardiac injury independent of angiotensin II receptors.

AIMS: Angiotension II (Ang II) plays a central role in the pathogenesis of renin-angiotensin-aldosterone system (RAAS)-induced heart failure. Mst1 exerts its function in cardiomyocytes subjected to pathological stimuli via inhibiting autophagy and aggravating apoptosis, but its role in RAAS-mediated cardiac injury is still unknown. Here, we aimed to determine whether cardiomyocyte-specific Mst1 knockout can alleviate Ang II-induced cardiac injury by improving cardiomyocyte autophagy and whether these functions depend on Ang II receptors. RESULTS: Mst1 knockout alleviated Ang II-induced heart failure, without affecting blood pressure and compensatory concentric hypertrophy. Mst1 specific knockout improved the effects of Ang II on cardiomyocyte autophagy, as evidenced by further increased LC3-II expression and decreased P62 expression. More typical autophagosomes accompanied by less damaged mitochondria were also observed by electron microscopy in Ang II-treated Mst1Δ/Δ mice. In vitro, Mst1 knockdown promoted cardiomyocyte autophagic flux, as demonstrated by more GFP-mRFP-LC3 puncta per cell. Increased LC3-II and decreased P62 expression both in the presence and absence of chloroquine were observed in Mst1 knockdown cardiomyocytes administered with Ang II. Treatment with 3-MA, an inhibitor of autophagy, abolished the beneficial effects of Mst1 knockout against Ang II-induced cardiac dysfunction. The compensatory effects of Ang II on upregulated autophagy were associated with Mst1 inhibition. Interestingly, the knockdown or antagonization of AT1R inhibited cardiomyocyte autophagy, which may represent a threat to cardiac function. Importantly, Mst1 knockout consistently enhanced cardiomyocyte autophagy following the knockdown or blocking of AT1R and AT2R. CONCLUSION: Cardiomyocyte-specific Mst1 knockout alleviates Ang II-induced cardiac injury by enhancing cardiomyocyte autophagy. Mst1 inhibition may counteract the undesirable effects of Ang II receptors blockage on cardiomyocyte autophagy and represent a promising complementary treatment strategy against Ang II-induced cardiac injury.

Melatonin activates Parkin translocation and rescues the impaired mitophagy activity of diabetic cardiomyopathy through Mst1 inhibition.

Mitophagy eliminates dysfunctional mitochondria and thus plays a cardinal role in diabetic cardiomyopathy (DCM). We observed the favourable effects of melatonin on cardiomyocyte mitophagy in mice with DCM and elucidated their underlying mechanisms. Electron microscopy and flow cytometric analysis revealed that melatonin reduced the number of impaired mitochondria in the diabetic heart. Other than decreasing mitochondrial biogenesis, melatonin increased the clearance of dysfunctional mitochondria in mice with DCM. Melatonin increased LC3 II expression as well as the colocalization of mitochondria and lysosomes in HG-treated cardiomyocytes and the number of typical autophagosomes engulfing mitochondria in the DCM heart. These results indicated that melatonin promoted mitophagy. When probing the mechanism, increased Parkin translocation to the mitochondria may be responsible for the up-regulated mitophagy exerted by melatonin. Parkin knockout counteracted the beneficial effects of melatonin on the cardiac mitochondrial morphology and bioenergetic disorders, thus abolishing the substantial effects of melatonin on cardiac remodelling with DCM. Furthermore, melatonin inhibited Mammalian sterile 20-like kinase 1 (Mst1) phosphorylation, thus enhancing Parkin-mediated mitophagy, which contributed to mitochondrial quality control. In summary, this study confirms that melatonin rescues the impaired mitophagy activity of DCM. The underlying mechanism may be attributed to activation of Parkin translocation via inhibition of Mst1.