Ding, Jingzhong

Abstract Cellular senescence is a biological aging process that is exacerbated by obesity and leads to inflammation and age- and obesogenic-driven chronic diseases including type 2 diabetes. Caloric restriction (CR) may improve metabolic function in part by reducing cellular senescence and the pro-inflammatory senescence-associated phenotype (SASP). We conducted an ancillary investigation of an 18-week randomized controlled trial (RCT) of CR (n = 31) or Control (n = 27) in 58 middle-aged/older adults (57.6 ± 5.8 years; 75% Women) with obesity and prediabetes. We measured mRNA expression of select senescence and apoptosis genes in blood CD3 + T cells (qRT-PCR) and a panel of 25 plasma SASP proteins (Luminex/multiplex; ELISA). Participants randomized to CR lost −10.8 ± 0.9 kg (−11.3% ± 5.4%) over 18 weeks compared with +0.5 ± 0.9 kg (+0.03% ± 3.5%) in Control group. T-cell expression of senescence biomarkers, p16INK4a and p21CIP1/WAF1, and apoptosis markers, BCL2L1 and BAK1, was not different between CR and Control groups in age, race, and sex-adjusted mixed models (p > .05, all). Iterative principal axis factor analysis was used to develop composite SASP Factors, and the Factors comprising TNFRI, TNFRII, uPAR, MMP1, GDF15, OPN, Fas, and MPO were significantly altered with CR intervention (age, sex, race-adjusted mixed model time × treatment F = 4.17, p ≤ .05) and associated with the degree of weight loss (R2 = 0.12, p ≤ .05). Our study provides evidence from an RCT that specific circulating biomarkers of senescent cell burden are changed by CR in middle-aged and older adults with obesity and prediabetes. Future studies compare tissue and circulating levels of p16INK4a and pro-inflammatory SASP biomarkers in other populations, and interventions.

AbstractBackgroundThe effect of an intensive lifestyle intervention (ILI) on Alzheimer’s disease (AD) blood‐based biomarker levels and cognitive outcomes among individuals with type 2 diabetes (T2D) is unknown. We examined AD biomarkers and cognitive outcomes in the Look AHEAD Study.MethodParticipants aged 45‐76 years were randomized at baseline to a 10‐year ILI or a diabetes support and education (DSE) condition. Cognitive assessments at years 8‐18 included measures of attention, executive function, global function, and memory. Mild cognitive impairment (MCI) and probable dementia were adjudicated by an expert panel. Stored baseline and end‐of‐intervention plasma samples were analyzed with the Quanterix Simoa HD‐X Analyzer. Changes in Aβ42/Aβ40, ptau181, neurofilament light chain (NfL), and glial fibrillary acidic protein (GFAP) were evaluated in relation to randomization status, demographic characteristics, and cognitive outcomes. Cognitive scores and biomarker levels were converted to z‐scores. Cognitive trajectories were evaluated using mixed models to account for repeated measures; logistic regression was used for a composite outcome of MCI/dementia. Models were adjusted for baseline characteristics (age, sex, education, race/ethnicity, body mass index (BMI), CVD history, hypertension, diabetes duration, eGFR), APOE‐ε4, randomization arm, time from randomization, and time between blood draw and cognitive testing.ResultThe mean age of 779 participants was 61.4 years; 56% = female, 22.8% = APOE ε4+, mean BMI = 34.8, baseline diabetes duration >5 years = 57%, 16.7% Black, 12.5% Hispanic, 66.2% White, and 4.7% other racial and ethnic groups. There were no associations between the intervention and biomarker levels at baseline or biomarker change over time. Increases in NfL levels significantly predicted lower memory (‐0.04 ±0.01; p = 0.002), global cognition scores (‐0.05 ±0.02; p = 0.011), executive function (‐0.04 ±0.01; p = 0.01), as well as increased risk of MCI/probable dementia (odds ratio [OR] 1.10, 95% CI 1.02‐1.19). Increases in GFAP predicted lower memory (‐0.10 ±0.03; p = 0.0001), global cognition (‐0.09 ±0.03; p = 0.009), executive function scores (‐0.12 ±0.03; p<0.0001), and increased risk of MCI/probable dementia (OR 1.24, 95% CI 1.09‐1.41).ConclusionThere was no association between the intervention and changes in biomarker levels. Increasing levels of NfL and GFAP over the ∼10 year period were associated with reduced cognitive performance and increased risk of MCI/probable dementia.

Abstract There are no circulating markers exclusive to cell senescence for clinical trials in middle-aged/older adults. In this study we evaluated T-cell expression of tumor suppressor protein p16INK4a and plasma senescence associated secretory proteins (SASP)-factors in the context of an 18-week randomized trial of caloric restriction (CR) compared to a weight stable Control. The analysis includes 55 middle-aged/older adults (75%Women; 33%African American; 57.6±5.8 years) with obesity and prediabetes. We measured mRNA expression of select senescence and apoptosis gene transcripts (p16INK4a, p21, BCL2L, BAK1) in peripheral blood CD3+ T-cells (quantitative-RT-PCR) and a panel of 27 plasma SASP proteins (Luminex/multiplex; ELISA). Weight loss in those randomized to CR was -10.8±0.9 kg compared to +0.5±0.9 kg in Control. Using mixed models, T-cell expression of senescence-biomarkers p16INK4a, p21, BCL-2L, and apoptosis-marker BAK1 were not different between CR and control at 18 weeks (time × treatment adjusted for age, race, and sex, all p&gt;0.05). We explored associations between biomarkers with weight loss; moderate spearman correlations (rs=0.28 to 0.64) were observed between weight loss and change in plasma SASP-factors (Activin A, I-CAM, MMP1, PAI-1, TNF-RI, TNF-RII, VEGF, uPAR, p&lt; 0.05 all), but not T-cell biomarker expression. We evaluated associations between biomarkers and found change in T-cell p16INK4a was associated with change in plasma SASP-factors, Fas (rs=0.51), osteopontin (rs=0.34), myeloperoxidase (rs=0.39), and MMP2 (rs=0.40) (CR+Control combined). Among middle-aged/older persons with obesity undergoing 18-weeks CR, changes in T cell p16INK4a expression were correlated with reductions in key SASP factors, and weight loss was associated with lower pro-inflammatory SASP profile.

Background: Serum levels of vascular cell adhesion molecule-1 (VCAM-1) are reflective of endothelial activation, a pathologic process that is associated with subclinical cardiac dysfunction. While VCAM-1 has been implicated in the pathogenesis of heart failure (HF) with preserved ejection fraction (HFpEF), the prospective association of VCAM-1 with clinically overt HF is unclear. Methods: In the Multi-Ethnic Study of Atherosclerosis, we evaluated the association of VCAM-1 at Exam 2 (2002-2004) with incident HF across ejection fraction (EF) categories (HFpEF and HF with reduced EF [HFrEF]) after adjustment for cardiovascular risk factors. Incident HF was adjudicated as first hospitalization for symptomatic HF, requiring specific clinical and/or imaging criteria. Results: Of 2,298 participants (mean age: 63.0 years, female: 53%), those with higher VCAM-1 were more likely white race, had higher blood pressure, and lower renal function. Over a median of 16.0 years, there were 102 HF events (HFpEF = 65; HFrEF = 37) ( Figure ). After covariate adjustment, VCAM-1 was independently associated with incident HF ( Table ). Upon evaluation of HF subtypes, VCAM-1 was associated with incident HFpEF, and risk effect estimates were consistent for incident HFrEF. The association of VCAM-1 with incident HF was consistent across the spectrum of age, sex, and BMI. Conclusion: In a multiethnic cohort, VCAM-1 was independently associated with incident HF over long-term follow up. These findings suggest a potential role for endothelial activation in driving clinical HF. Lifestyle and pharmacologic therapies that decrease endothelial activation may prevent the progression to clinical HF.

Background Serum levels of vascular cell adhesion molecule‐1 (VCAM‐1) are reflective of endothelial activation. Although VCAM‐1 has been implicated in the pathogenesis of heart failure with preserved ejection fraction (HFpEF), the prospective association of VCAM‐1 with development of clinically overt heart failure (HF) across ejection fraction categories is unclear. Methods and Results In MESA (the Multi‐Ethnic Study of Atherosclerosis), we evaluated the association of VCAM‐1 at examination 2 (2002–2004) with incident HF (HFpEF and HF with reduced ejection fraction) after adjustment for cardiovascular risk factors. Incident HF was independently adjudicated as first hospitalization for symptomatic HF. Among 2297 participants (mean age, 63 years; women, 53%), those with higher VCAM‐1 were more likely to be White race, had higher blood pressure, and had lower kidney function. Over a median of 14.4 years, there were 102 HF events (HFpEF=65; HF with reduced ejection fraction=37). After covariate adjustment, each doubling of VCAM‐1 was associated with incident HF (hazard ratio [HR], 1.94; 95% CI, 1.17–3.23; P =0.01). This association appeared stronger among current/former smokers compared with never smokers. On evaluation of HF subtypes, VCAM‐1 was associated with incident HFpEF (HR, 1.97; 95% CI, 1.04–3.72; P =0.04) but not with incident HF with reduced ejection fraction, although risk estimates were consistent (HR, 1.82; 95% CI, 0.79–4.21; P =0.16). Conclusions In a multiethnic cohort, VCAM‐1 was significantly associated with incident HF over long‐term follow‐up. These findings suggest a potential role for endothelial activation in driving clinical HF, and specifically HFpEF. Therapies that decrease endothelial activation may prevent the progression from cardiovascular risk factors to clinical HF.