Background Inherited methylmalonic acidemia is characterized by mitochondrial dysfunction, oxidative stress, and damage of mitochondria-rich organs in children. It is unclear whether methylmalonic acid (MMA) is related to poor prognosis in adults. The study aims to investigate the associations of MMA with all-cause and cause-specific mortality in the general population. Methods Overall, 23,437 adults from the US National Health and Nutrition Examination Survey (NHANES) were enrolled. NHANES 1999–2004 and 2011–2014 were separately used as primary and validation subsets (median follow-up 13.5 and 2.8 years, respectively). Circulating MMA was measured with gas chromatography/mass spectrophotometry. Hazard ratios (HR) were estimated using weighted Cox regression models. Results During 163,632 person-years of follow-up in NHANES 1999–2004, 3019 deaths occurred. Compared with participants with MMA <120 nmol/L, those with MMA≥250 nmol/L had increased all-cause and cardiovascular mortality in the multivariable-adjusted model [HR(95%CI), 1.62 (1.43–1.84) and 1.66 (1.22–2.27), respectively]. The association was especially significant among participants with normal cobalamin. MMA remained an independent predictor of all-cause mortality occurring whether within 5-year, 5–10 years, or beyond 10-year of follow-up (each p for trend≤0.007). That association was repeatable in NHANES 2011–2014. Moreover, baseline MMA improved reclassification for 10-year mortality in patients with cardiovascular disease (net reclassification index 0.239, integrated discrimination improvement 0.022), overmatched established cardiovascular biomarkers C-reactive protein or homocysteine. Conclusions Circulating level of mitochondrial-derived MMA is strongly associated with elevated all-cause and cardiovascular mortality. Our results support MMA as a surrogate biomarker of mitochondrial dysfunction to predict poor prognosis in adults. The biological mechanisms under cardiovascular disease warrant further investigation.

ObjectiveD-dimer might serve as a marker of thrombogenesis and a hypercoagulable state following plaque rupture. Few studies explore the association between baseline D-dimer levels and the incidence of heart failure (HF), all-cause mortality in an acute myocardial infarction (AMI) population. We aimed to explore this association.MethodsWe enrolled 4504 consecutive patients with AMI with complete data in a prospective cohort study and explored the association of plasma D-dimer levels on admission and the incidence of HF, all-cause mortality.ResultsOver a median follow-up of 1 year, 1112 (24.7%) patients developed in-hospital HF, 542 (16.7%) patients developed HF after hospitalisation and 233 (7.1%) patients died. After full adjustments for other relevant clinical covariates, patients with D-dimer values in quartile 3 (Q3) had 1.51 times (95% CI 1.12 to 2.04) and in Q4 had 1.49 times (95% CI 1.09 to 2.04) as high as the risk of HF after hospitalisation compared with patients in Q1. Patients with D-dimer values in Q4 had more than a twofold (HR 2.34; 95% CI 1.33 to 4.13) increased risk of death compared with patients in Q1 (p<0.001). But there was no association between D-dimer levels and in-hospital HF in the adjusted models.ConclusionsD-dimer was found to be associated with the incidence of HF after hospitalisation and all-cause mortality in patients with AMI.

Rationale : Atherosclerosis plaque rupture (PR) is the pathological basis and chief culprit of most acute cardiovascular events and death. Given the complex and important role of macrophage apoptosis and autophagy in affecting plaque stability, an important unanswered question include is whether, and how, immunity-related GTPase family M protein (IRGM) and its mouse orthologue IRGM1 affect macrophage survival and atherosclerotic plaque stability. Methods: To investigate whether serum IRGM of ST-segment elevation myocardial infarction (STEMI) patients is related to plaque morphology, we divided 85 STEMI patients into those with and without plaque rupture (PR and non-PR, respectively) based on OCT image analysis, and quantified the patients' serum IRGM levels. Next, we engineered Irgm1 deficient mice ( Irgm1 +/- ) and chimera mice with Irgm1 deficiency in the bone marrow on an ApoE -/- background, which were then fed a high-fat diet for 16 weeks. Pathological staining was used to detect necrotic plaque cores, ratios of neutral lipids and cholesterol crystal, as well as collagen fiber contents in these mice to characterize plaque stability. In addition, immunofluorescence, immunohistochemical staining and western blot were used to detect the apoptosis of macrophages in the plaques. In vitro , THP-1 and RAW264.7 cells were stimulated with ox-LDL to mimic the in vivo environment, and IRGM/IRGM1 expression were modified by specific siRNA (knockdown) or IRGM plasmid (knocked-in). The effect of IRGM/Irgm1 on autophagy and apoptosis of macrophages induced by ox-LDL was then evaluated. In addition, we introduced inhibitors of the JNK/p38/ERK signaling pathway to verify the specific mechanism by which Irgm1 regulates RAW264.7 cell apoptosis. Results: The serum IRGM levels of PR patients is significantly higher than that of non-PR patients and healthy volunteers, which may be an effective predictor of PR. On a high-fat diet, Irgm1 -deficient mice exhibit reduced necrotic plaque cores, as well as neutral lipid and cholesterol crystal ratios, with increased collagen fiber content. Additionally, macrophage apoptosis is inhibited in the plaques of Irgm1 -deficient mice. In vitro , IRGM/Irgm1 deficiency rapidly inhibits ox-LDL-induced macrophage autophagy while inhibiting ox-LDL-induced macrophage apoptosis in late stages. Additionally, IRGM/Irgm1 deficiency suppresses reactive oxygen species (ROS) production in macrophages, while removal of ROS effectively inhibits macrophage apoptosis induced by IRGM overexpression. We further show that Irgm1 can affect macrophage apoptosis by regulating JNK/p38/ER...

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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.

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Methylmalonic acid (MMA) can act as a diagnosis of hereditary methylmalonic acidemia and assess the status of vitamin B12. Moreover, as a new potential biomarker, it has been widely reported to be associated with the progression and prognosis of chronic diseases such as cardiovascular events, renal insufficiency, cognitive impairment, and cancer. MMA accumulation may cause oxidative stress and impair mitochondrial function, disrupt cellular energy metabolism, and trigger cell death. This review primarily focuses on the mechanisms and epidemiology or progression in the clinical study on MMA.

Acute coronary syndrome (ACS) caused by plaque rupture (PR) is the chief culprit behind cardiovascular death, yet its exact mechanism remains unclear. Immunity-related GTPase (IRGM/Irgm1) has been widely studied in several inflammatory diseases, but the role of IRGM/Irgm1 in atherosclerosis is poorly characterized. Here, we shed light on the mechanism by which IRGM/Irgm1 contributes to plaque vulnerability in atherosclerosis. We first identified ruptured and non-ruptured plaques by optical coherence tomography, and strikingly found that serum IRGM was highly expressed in ST-segment elevation myocardial infarction patients with PR. Next, we used ApoE-/-Irgm1+/+ and ApoE-/-Irgm1+/- mice and corresponding bone marrow chimeras to establish a model for advanced atherosclerosis, and found that Irgm1 could aggravate progression of atherosclerotic plaques. We confirmed that Irgm1 contributes to macrophage apoptosis by promoting the production of reactive oxygen species. Finally, we discovered that Irgm1 induces macrophage apoptosis by activating the MAPK signaling pathway. Our findings highlight the mechanism by which IRGM/Irgm1 contributes to the formation of vulnerable plaques and may offer a novel target for the timely treatment of ACS.