Association of myocardial iron deficiency based on T2* CMR with the risk of mild left ventricular dysfunction in HIV-1-infected patients.

Objectives: This study sought to noninvasively determine myocardial iron levels in HIV-1-infected patients using CMR and explore the association between T2* values and mild left ventricular systolic dysfunction (LVSD). Methods: This prospective study was conducted from June 2019 to July 2021. HIV-1-infected adults and healthy controls were consecutively enrolled for CMR exam. CMR exam included the assessment of myocardium iron content (T2*), cardiac function (cine), inflammation (T2), and fibrosis (through extracellular volume fraction [ECV] and late gadolinium enhancement [LGE]) measurements. Mild LVSD is defined as a left ventricular ejection fraction (LVEF) between 40% and 49%. Results: Of 47 HIV-1-infected patients enrolled, 12 were diagnosed with mild LVSD (HIV-1+/LEVF+) and 35 were diagnosed with preserved LV function (HIV-1+/LEVF-). Compared with healthy controls, HIV-1-infected patients displayed higher T2*, T1, T2, ECV values and lower global circumferential strain (GCS) and global radial strain (GRS) (all P < 0.05). However, between patients with and without mild LVSD, only the T2* values and ECV (all P <0.05) were different. The association between increased T2* values (>26 ms) and mild LVSD remained significant after adjusting for the established univariate predictors (ECV >32.9%, T1 values >1336 ms) of mild LVSD (odds ratio [OR], 10.153; 95% confidence interval [CI] 1.565-65.878, P = 0.015). Conclusions: Myocardial T2* values were elevated in HIV-1-infected patients, supporting the notion that ID was associated with mild LVSD. Our findings highlight the potential for ID in HIV-1-infected patients as an auxiliary biomarker to monitor the course of LVSD.

Clinical value of resting cardiac dual-energy CT in patients suspected of coronary artery disease.

BACKGROUND: Rest/stress myocardial CT perfusion (CTP) has high diagnostic value for coronary artery disease (CAD), but the additional value of resting CTP especially dual-energy CTP (DE-CTP) beyond coronary CT angiography (CCTA) in chest pain triage remains unclear. We aimed to evaluate the diagnostic accuracy of resting myocardial DE-CTP, and additional value in detecting CAD beyond CCTA (obstructive stenosis: ≥ 50%) in patients suspected of CAD. METHODS: In this prespecified subanalysis of 54 patients, we included patients suspected of CAD referred to invasive coronary angiography (ICA). Diagnostic accuracy of resting myocardial DE-CTP in detecting myocardial perfusion defects was assessed using resting 13N-ammonia positron emission tomography (PET) as the gold standard. Diagnostic accuracy of cardiac dual-energy CT in detecting flow-limiting stenoses (justifying revascularization) by CCTA combined with resting myocardial DE-CTP, using ICA plus resting 13N-ammonia PET as the gold standard. The CCTA and DE-CTP datasets derived from a single-phase scan performed with dual-energy mode. RESULTS: For detecting myocardial perfusion defects, DE-CTP demonstrated high diagnostic accuracy with a sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) of 95.52%, 85.93%, and 0.907 on a per-segment basis. For detecting flow-limiting stenoses by CCTA alone, sensitivity, specificity, and AUC were 100%, 56.47%, and 0.777 respectively on a per-vessel basis. For detecting flow-limiting stenoses by CCTA combined with resting myocardial DE-CTP, sensitivity, specificity, and AUC were 96.10%, 95.29% and 0.956 respectively on a per-vessel basis. Additionally, CCTA combined with resting myocardial DE-CTP detected five patients (9%) with no obstructive stenosis but with myocardial perfusion defects confirmed by ICA plus 13N-ammonia PET. CONCLUSIONS: Resting cardiac DE-CTP demonstrates a high diagnostic accuracy in detecting myocardial perfusion defects and provides an additional clinical value by reducing rates of false-positive and false-negative patients beyond CCTA in patients suspected of CAD.

Cardiac Involvement in Human Immunodeficiency Virus Infected Patients: An Observational Cardiac Magnetic Resonance Study.

Objectives: To investigate the subclinical imaging changes in terms of myocardial inflammation and fibrosis and to explore the risk factors associated with myocardial fibrosis by cardiac magnetic resonance (CMR) approach in a Chinese HIV/AIDS cohort. Methods: We evaluated myocardial function (cine), myocardial inflammation (T1, T2), and myocardial fibrosis (through extracellular volume fraction [ECV] and late gadolinium enhancement [LGE]) by a multiparametric CMR scan protocol in a total of 68 participants, including 47 HIV-infected individuals, who were divided into two groups: asymptomatic HIV (HIV+) (n = 30), and acquired immunodeficiency syndrome (AIDS) (n = 17), and 21 healthy controls. Results: HIV-infected patients had lower left (55.3 ± 6.5 vs. 63.0 ± 7.9%, P < 0.001) and right ventricular systolic function (35.9 ± 15.7 vs. 50.8 ± 9.3%, P < 0.001). Radial systolic strain (30.7 ± 9.3 vs. 39.3 ± 9.4%, P = 0.001), circumferential systolic strain (-17.5 ± 2.6 vs. -19.4 ± 2.7%, P = 0.008), and longitudinal systolic strain (-9.4 ± 5.7 vs. -12.8 ± 3.1%, P = 0.012) were also decreased in HIV. Native T1 relaxation time (1,337.2 ± 70.2 vs. 1,249.5 ± 47.0 ms, P < 0.001), ECV value (33.5 ± 6.2 vs. 28.5 ± 2.9 ms, P = 0.026), and T2 relaxation time (45.2 ± 3.5 vs. 42.0 ± 2.6 ms, P = 0.001) were higher in HIV-infected patients compared with controls. Myocardial fibrosis, predominantly in the mid-inferior wall, was detected in 24.4% of the HIV-infected patients. HIV+ had a significantly lower value of ECV [29.1 (26.1, 31.8) vs. 35.2 (31.8, 41.9) %, P < 0.001] and frequency of LGE [3/25 (8%) vs. 7/16 (43.8%), P = 0.014)] compared with AIDS. AIDS was associated with myocardial fibrosis. Conclusions: HIV-infected patients were associated with changes in myocardial function and higher rates of subclinical myocardial inflammation and fibrosis, which were more abnormal with greater severity of the disease. AIDS was associated with myocardial fibrosis, where the observations supported earlier initiation of antiretroviral therapy in the Chinese HIV/AIDS cohort.

Measurement of visceral fat and abdominal obesity by single-frequency bioelectrical impedance and CT: a cross-sectional study.

OBJECTIVES: The measurement of visceral fat (VF) is clinically important for the identification of individuals at high risk of visceral obesity-related health conditions. Bioelectrical impedance analysis (BIA) is a widely available and frequently used body composition assessment method, but there have been few validation studies for the measurement of VF. This validation study investigated agreement between BIA and CT for the assessment of VF in adults. DESIGN: Cross-sectional study. SETTING: Between 2015 and 2016 in China. PARTICIPANTS: A total of 414 adults (119 men and 295 women) aged 40-82 years. PRIMARY AND SECONDARY OUTCOME MEASURES: CT-visceral fat area (VFA) was derived at the L2-3 and umbilicus level and VFA cut-offs for visceral obesity applied. BIA measurements of visceral fat level were compared with CT VFA findings using scatter plots and receiver operator characteristic (ROC) curves. RESULTS: Scatter plots showed poor agreement between BIA and CT-derived visceral fat measurements in both sexes (R=0.387-0.636). ROC curves gave optimum figures for sensitivity and specificity of 65% and 69% in women and 76% and 70% in men, respectively, for BIA to discriminate between adults with normal levels of VF and those with visceral obesity determined by CT. CONCLUSION: BIA has limited accuracy for the assessment of VF in adults in practice when compared with the criterion method.

Clinical Factors and Quantitative CT Parameters Associated With ICU Admission in Patients of COVID-19 Pneumonia: A Multicenter Study.

The clinical spectrum of COVID-19 pneumonia is varied. Thus, it is important to identify risk factors at an early stage for predicting deterioration that require transferring the patients to ICU. A retrospective multicenter study was conducted on COVID-19 patients admitted to designated hospitals in China from Jan 17, 2020, to Feb 17, 2020. Clinical presentation, laboratory data, and quantitative CT parameters were also collected. The result showed that increasing risks of ICU admission were associated with age > 60 years (odds ratio [OR], 12.72; 95% confidence interval [CI], 2.42-24.61; P = 0.032), coexisting conditions (OR, 5.55; 95% CI, 1.59-19.38; P = 0.007) and CT derived total opacity percentage (TOP) (OR, 8.0; 95% CI, 1.45-39.29; P = 0.016). In conclusion, older age, coexisting conditions, larger TOP at the time of hospital admission are associated with ICU admission in patients with COVID-19 pneumonia. Early monitoring the progression of the disease and implementing appropriate therapies are warranted.

Retrospective assessment of at-risk myocardium in reperfused acute myocardial infarction patients using contrast-enhanced balanced steady-state free-precession cardiovascular magnetic resonance at 3T with SPECT validation.

BACKGROUND: Contrast-enhanced (CE) steady-state free precession (SSFP) CMR at 1.5T has been shown to be a valuable alternative to T2-based methods for the detection and quantifications of area-at-risk (AAR) in acute myocardial infarction (AMI) patients. However, CE-SSFP's capacity for assessment of AAR at 3T has not been investigated. We examined the clinical utility of CE-SSFP and T2-STIR for the retrospective assessment of AAR at 3T with single-photon-emission-computed tomography (SPECT) validation. MATERIALS AND METHODS: A total of 60 AMI patients (ST-elevation AMI, n = 44;  non-ST-elevation AMI, n = 16) were recruited into the CMR study between 3 and 7 days post revascularization. All patients underwent T2-STIR, CE-bSSFP and late-gadolinium-enhancement CMR. For validation, SPECT images were acquired in a subgroup of patients (n = 30). RESULTS: In 53 of 60 patients (88 %), T2-STIR was of diagnostic quality compared with 54 of 60 (90 %) with CE-SSFP. In a head-to-head per-slice comparison (n = 365), there was no difference in AAR quantified using T2-STIR and CE-SSFP (R2 = 0.92, p < 0.001; bias:-0.4 ± 0.8 cm2, p = 0.46). On a per-patient basis, there was good agreement between CE-SSFP (n = 29) and SPECT (R2 = 0.86, p < 0.001; bias: - 1.3 ± 7.8 %LV, p = 0.39) for AAR determination. T2-STIR also showed good agreement with SPECT for AAR measurement (R2 = 0.81, p < 0.001, bias: 0.5 ± 11.1 %LV, p = 0.81). There was also a strong agreement between CE-SSFP and T2-STIR with respect to the assessment of AAR on per-patient analysis (R2 = 0.84, p < 0.001, bias: - 2.1 ± 10.1 %LV, p = 0.31). CONCLUSIONS: At 3T, both CE-SSFP and T2-STIR can retrospectively quantify the at-risk myocardium with high accuracy.

Exosomes Enhance Adhesion and Osteogenic Differentiation of Initial Bone Marrow Stem Cells on Titanium Surfaces.

Successful osseointegration involves the biological behavior of bone marrow stem cells (BMSCs) on an implant surface; however, the role of BMSC-derived extracellular vesicles (EVs)/exosomes in osseointegration is little known. This study aimed to: (i) explore the interaction force between exosomes (Exo) and cells on a titanium surface; (ii) discuss whether the morphology and biological behavior of BMSCs are affected by exosomes; and (iii) preliminarily investigate the mechanism by which exosomes regulate cells on Ti surface. Exosomes secreted by rat BMSCs were collected by ultracentrifugation and analyzed using transmission electron microscopy and nanoparticle tracking analysis. Confocal fluorescence microscopy, scanning electron microscopy, Cell Counting Kit-8 (CCK-8), quantitative real-time polymerase chain reaction techniques, and alkaline phosphatase bioactivity, Alizarin Red staining, and quantification were used to investigate the exosomes that adhere to the Ti plates under different treatments as well as the morphological change, adhesion, spread, and differentiation of BMSCs. We found that exosomes were efficiently internalized and could regulate cell morphology and promoted the adhesion, spreading, and osteogenic differentiation of BMSCs. These were achieved partly by activating the RhoA/ROCK signaling pathway. Our discovery presents a new insight into the positive regulatory effect of exosomes on the biological behaviors of BMSCs on Ti surface and provides a novel route to modify the surface of a Ti implant.

Age- and sex-related differences in muscle strength and physical performance in older Chinese.

BACKGROUND: Little is known about muscle strength and physical performance in Chinese. AIM: This study aimed to assess the age- and sex-related differences in muscle strength and physical performance in older Chinese. METHODS: Three hundred and eight healthy participants (110 males and 198 females) age 68.3 ± 6.1 (mean ± SD) years were enrolled in this cross-sectional study. The handgrip muscle strength (HGS) of the dominant hand was measured using a Jamar dynamometer. Physical performance was assessed by the Timed Up and Go test (TUG). The EuroQol five-dimension questionnaire (EQ-5D) was used to evaluate participants' health status. RESULTS: Men showed higher levels of HGS with a smaller percentage having low muscle strength compared with women. No differences were observed in TUG between sexes. No significant association of TUG and age was observed in males. However, older females had increased TUG and hence poorer performance. Good health status was associated with better physical performance but was not related to muscle strength in either sex. DISCUSSION: In men, there was no correlation between age and TUG, although a negative association with handgrip muscle strength was observed. For women, both muscle strength and physical performance declined with age. The sex-related differences in aging effects on physical performance in our study could partly explain why women have a higher incidence of hip fracture than men. CONCLUSION: Chinese women may be more vulnerable to severe sarcopenia in old age than men.