Immunological responsiveness of intestinal tissue explants and mucosal mononuclear cells to ex vivo stimulation

BACKGROUND

There are limited data on the immunological responsiveness of healthy intestinal tissue when it is cultured and stimulated ex vivo. Such an ex vivo model has the potential to be a valuable tool in understanding disease pathogenesis and as a preclinical tool for the assessment of candidate therapeutic agents used to treat inflammatory bowel disease (IBD).

AIM

We undertook a comprehensive study to evaluate ex vivo immunological responses of intestinal tissue and isolated mucosal mononuclear cells (MMC) to a broad range of stimuli.

METHODS

Colorectal biopsies (explants) were obtained from healthy participants by flexible sigmoidoscopy and were placed either directly into culture or digested to isolate MMC prior to placement in culture. Explants or MMC were treated with polyinosinic:polycytidylic acid (Poly IC), phytohemagglutinin (PHA), lipopolysacccharides from E Coli (LPS), anti-CD3/CD28 antibodies, or IL-1β/TNF-α for 24 h. Supernatants were assayed for 40 inflammatory biomarkers using multiplexed enzyme-linked immunosorbent assay (ELISA). The isolated MMCs were further characterized using twelve color flow cytometry.

RESULTS

Explants have greater weight adjusted constitutive expression of inflammatory biomarkers than MMCs. Biomarker responses varied as a function of immunogen and use of intact tissue or isolated cells. PHA applied to intact explants was the most effective agent in inducing biomarker changes. Stimulation induced activated and memory cellular phenotypes in both explants and MMCs.

CONCLUSIONS

The breadth and magnitude of responses from intact and enzymatically digested intestinal tissue explants stimulated with exogenous immunogens are complex and vary by tissue form and treatment. Overall, PHA stimulation of intact explants produced the most robust responses in normal human colorectal tissue. This system could potentially serve as a preliminary model of the disease state, suitable for small scale screening of new therapeutic agents prior to using IBD patient derived tissue.

Geospatial Visualization of Mobile Stroke Unit Dispatches: A Method to Optimize Service Performance

Background

Timely treatment of acute ischemic stroke is crucial to optimize outcomes. Mobile stroke units (MSU) have demonstrated ultrafast treatment compared to standard emergency care. Geospatial analysis of the distribution of MSU cases to optimize service delivery has not been reported.

Methods

We aggregated all first-year MSU dispatch occurrences and all cases classified by clinical teams as true stroke by zip code and calculated dispatch and true stroke incidence rates. We mapped dispatch and stroke cases and symbolized incidence rates by standard deviation. We confirmed visual impressions of clusters from map inspection by local Moran's I, boxplot inspection, and t test. We calculated service areas using drive times to meet dispatch and true stroke need.

Results

A significant cluster of high dispatch incident rate was confirmed around our MSU base in urban Memphis within a 5-min driving area supporting the initial placement of the MSU based on 911 activation. A significant cluster of high true stroke rate was confirmed to the east of our MSU base in suburban Memphis within a 10-min driving area. Mean incident longitude of cases of true stroke versus disregarded status was significantly eastward (p = 0.001785).

Conclusion

Our findings will facilitate determination of socio-spatial antecedents of neighborhood overutilization of 911 and MSU services in our urban neighborhoods and service delivery optimization to reach neighborhoods with true stroke burden.

Psychological and Physical Health in Military Amputees During Rehabilitation: Secondary Analysis of a Randomized Controlled Trial

BACKGROUND

Service members who have experienced combat trauma with resulting amputation are at risk for compromised quality of life postamputation. Monitoring mental and physical health in amputees returning from the war is of paramount importance. This study examined changes in physical and mental health-related quality of life in service members following traumatic unilateral, transtibial amputation (TTA) during a 12-week period of rehabilitation before and after receiving a prosthesis.

METHOD

This study is a secondary analysis from a randomized controlled trial (RCT) of military service members starting Military Amputee Rehabilitation Program (MARP) following a traumatic TTA. The study examined change in SF-36 Physical Component Summary (PCS) and Mental Component Summary (MCS) scores as two aspects of health-related quality of life. Forty-four injured service members, aged 19 to 46, were recruited into the RCT. Participants were randomized into 12 weeks of MARP plus home neuromuscular electrical stimulation therapy (n = 23) or MARP alone (N = 21) and compared at baseline, 6, and 12 weeks on: SF-36 PCS and MCS scores. Linear mixed models examined time and group differences and their interaction for the MCS and PCS scores. A multivariate mixed model tested whether MCS and PCS scores differed.

RESULTS

For the combined rehabilitation cohort, MCS did not differ over 12 weeks (p = 0.27) with scores at week 0 of M = 56.7 (SD = 11.9) and at week 12 of M = 52.7 (SD = 11.4), similar to healthy controls (age = 25-34, M = 51.0, SD = 7.6). Scores did not differ between treatment groups (p = 0.28) with no group by time interaction (p = 0.34). The MCS significantly declined over time (p = 0.05) after adjustment for covariates. PCS improved over 12 weeks (p < 0.0001) in the total rehabilitation group with scores at week 0 of M = 34.0 (SD = 8.1) to M = 41.8 (SD = 8.4) at week 12, significantly lower than healthy controls (age = 25-34, M = 54.1, SD = 6.6). Scores did not differ between treatment groups (p = 0.89), and there was no group by time interaction (p = 0.34). An interaction between the PCS and MCS was observed such that the PCS improved over time, whereas the MCS did not significantly change (p = 0.0005).

DISCUSSION

War-injured transtibial amputees are at risk for compromised quality of life during rehabilitation. Self-perceived physical health improved as might be expected from rehabilitation. Self-perceived mental health did not. During rehabilitation, physical healing, psychological adjustment, and lifestyle adaptation are occurring simultaneously. However, more attention may need to be directed toward mental health during rehabilitation.

Abstract TP357: BP Management on the Mobile Stroke Unit for Ultra-Early Treatment of ICH and Acute Ischemic Stroke

Background: Lowering of blood pressure (BP) is discouraged in current ASA guidelines for emergency medical service (EMS) personnel. However, ultra-early treatment with IVtPA and BP lowering in ICH are possible on mobile stroke units (MSU). We examined the effectiveness and safety of two antihypertensive agents for MSU treatment.

Methods: Consecutive MSU patients were treated with target ICH BP parameters less than 140/90, and IVtPA BP parameters by current guidelines. BP was measured by noninvasive oscillometric cuff, and cycled every 5 minutes per EMS MSU protocol. Available agents were labetalol IV 10-20mg and/or nicardipine double-strength premix infusion started at 5mg/hour and titrated. Preference in usage, and effect were recorded and analyzed for the first year of MSU operation.

Results: During 168 service days, 127 acute stroke patients were transported (68±16, range 23-96 years; 58% women; 65% African American, 34% White; 1% Hispanic). Fifteen (12%) had hemorrhage on CT (1 aneurysmal SAH, 1 SDH, 1 subacute AIS with HT-2; 12 HTN ICH [median ICH score 2, IQR 1-3] of which 1 had a positive spot sign on CTA). AIS cases (n=100) had median NIHSS 9 (IQR 7-17); 38% were treated with IVtPA at a median 13 (IQR 11-16) minutes from scene arrival, one of these by IO route, with 1 angioedema and 0 sICH. Labetalol was used for 9 patients, with all but one (89%) requiring the addition of nicardipine infusion. In 24 patients nicardipine was the first agent selected, with 100% achieving target BP control prior to hospital arrival.

Conclusions: MSU use of nicardipine double-strength premix infusions provides rapid, reliable, and safe BP control. When time is of the essence, elimination of labetalol, in favor of a dihydropyridine calcium channel blocker infusion may provide the most rapid achievement of prescribed BP parameters.

Abstract WP215: Geospatial Visualization of Mobile Stroke Unit Dispatches: A Method to Optimize Service Performance

Background: Understanding geospatial regional stroke burden and emergency medical services (EMS) response locations may benefit attainment and distribution of prehospital resources, enabling rapid diagnosis and treatment. We sought to understand the spatial distribution of all Mobile Stroke Unit (MSU) dispatches and diagnosed strokes during the first year of operation.

Methods: All MSU dispatched cases from July 2016 to July 2017 were assembled and aggregated into groups based on stroke diagnosis status. The raw count of incidents was aggregated by zip code, normalized to population, and geocoded. The resulting incidence rate was symbolized by standard deviation and mapped by zip code for inspection. Five- and ten-minute drive time service areas were defined around our MSU base.

Results: A total of 420 dispatches for suspected stroke occurred, of which 394 were able to be geocoded. On the initial analysis of all 394 cases, a five-minute service area was sufficient to rapidly reach areas with high rates of suspected stroke burden (> 1.5 SD) (figure 1). However, repeating the analysis on 123 cases diagnosed as true strokes redefined the areas that were strongly positive for high stroke burden requiring a ten-minute service area from our MSU base (figure 2).

Conclusions: Use of geospatial findings helps plan EMS and MSU dispatch to high burden regional pockets of stroke, and may assist in improving dispatch scripting for 911 calls.

Circulating sex hormones in relation to anthropometric, sociodemographic and behavioural factors in an international dataset of 12,300 men

INTRODUCTION

Sex hormones have been implicated in the etiology of a number of diseases. To better understand disease etiology and the mechanisms of disease-risk factor associations, this analysis aimed to investigate the associations of anthropometric, sociodemographic and behavioural factors with a range of circulating sex hormones and sex hormone-binding globulin.

METHODS

Statistical analyses of individual participant data from 12,330 male controls aged 25-85 years from 25 studies involved in the Endogenous Hormones Nutritional Biomarkers and Prostate Cancer Collaborative Group. Analysis of variance was used to estimate geometric means adjusted for study and relevant covariates.

RESULTS

Older age was associated with higher concentrations of sex hormone-binding globulin and dihydrotestosterone and lower concentrations of dehydroepiandrosterone sulfate, free testosterone, androstenedione, androstanediol glucuronide and free estradiol. Higher body mass index was associated with higher concentrations of free estradiol, androstanediol glucuronide, estradiol and estrone and lower concentrations of dihydrotestosterone, testosterone, sex hormone-binding globulin, free testosterone, androstenedione and dehydroepiandrosterone sulfate. Taller height was associated with lower concentrations of androstenedione, testosterone, free testosterone and sex hormone-binding globulin and higher concentrations of androstanediol glucuronide. Current smoking was associated with higher concentrations of androstenedione, sex hormone-binding globulin and testosterone. Alcohol consumption was associated with higher concentrations of dehydroepiandrosterone sulfate, androstenedione and androstanediol glucuronide. East Asians had lower concentrations of androstanediol glucuronide and African Americans had higher concentrations of estrogens. Education and marital status were modestly associated with a small number of hormones.

CONCLUSION

Circulating sex hormones in men are strongly associated with age and body mass index, and to a lesser extent with smoking status and alcohol consumption.

Telomere Shortening, Inflammatory Cytokines, and Anti-Cytomegalovirus Antibody Follow Distinct Age-Associated Trajectories in Humans

A number of biological parameters have been cited as hallmarks of immune aging. However, it is not clear whether these multiple biological changes are the result of common underlying aging processes and follow correlated trajectories, or whether the patterns of change for multiple parameters vary across individuals and reflect heterogeneity in the aging process. Here, we have studied parameters of immune system aging through longitudinal analysis of telomere length, inflammatory cytokines, and antibody titer to cytomegalovirus (CMV) in 465 subjects ranging in age from 21 to 88 years at the first visit, with an average of 13 years (7-19 years) follow-up. We observed a highly variable rate of change in telomere length of PBMCs with a relatively slow average rate of telomere shortening (-16 bp/year). Similarly, there were significant increases with age in vivo in three inflammation-related cytokines (interferon gamma, IL-6, and IL-10) and in anti-CMV IgG titer, which varied widely across individuals as well. We further observed positive correlative changes among different inflammatory cytokines. However, we did not find significant correlations among the rate of changes in telomere length, inflammatory cytokines, and anti-CMV IgG titers. Our findings thus reveal that age-related trajectories of telomere attrition, elevated circulating inflammatory cytokines, and anti-CMV IgG are independent and that aging individuals do not show a uniform pattern of change in these variables. Immune aging processes are complex and vary across individuals, and the use of multiple biomarkers is essential to evaluation of biological aging of the immune system.

Health-related quality of life in active duty military: A secondary data analysis of two randomized controlled trials

BACKGROUND

Military service members with lower extremity injuries are at risk for compromised health-related quality of life during rehabilitation.

PURPOSE

The purpose of this secondary data analysis was to examine changes in self-perceived physical and mental health in two clinical trials of military service members during rehabilitation for a lower extremity injury.

METHODS

This study is a secondary analysis of existing data from two cohorts of active duty military service members with lower extremity injuries as they participated in separate randomized controlled trials.

DISCUSSION

A similar pattern for both physical and mental health was observed in both groups of participants. Perceptions of physical health improved significantly in both studies, whereas mental health perceptions may or may not have declined.

CONCLUSION

Increased attention to mental health may be important during rehabilitation after major and minor lower extremity injuries. Although perceptions of physical health improve, corresponding changes may not occur in mental health perceptions.

Abstract WP64: City-wide Stroke Team in the U.S. Delivers the Highest Intravenous Thrombolysis Treatment Rate

Background: An increasing shortage of vascular neurologists forced an academic provider to find a city-wide solution to offer 24x7 access to intravenous thrombolysis (IVT) across independent and competing health care systems in the area. We sought to prospectively evaluate the annual IVT treatment delivery in our population and compare it to leading stroke centers worldwide.

Methods: The largest single ER system and 3 other independent hospital providers in the area agreed to work with a single practice plan vascular neurology team (catchment area of 1,344,127 individuals). All acute ischemic stroke patients that were treated with IVT across all primary or tertiary care centers in our area were prospectively documented over a 12-month period (January-December 2015). A literature search was performed using narrative review methodology to document similar population-based treatment rates across leading stroke centers in North America, Europe and Australasia.

Results: A total of 552 patients received IVT with tissue plasminogen activator (tPA) in 2015. Single ER system delivered 433 IV tPA treatments and 119 more patients were treated in the remaining hospitals. The annual tPA treatment rate was 41 per 100.000 individuals (95%CI: 38-44) favorably comparable to published annual treatment rates from leading international stroke centers (Table, 1998 thru 2015).

Conclusions: A city-wide vascular neurology team can attend to patient populations across competing health care systems in the U.S. and deliver IVT at volumes and rates above those reported by leading treatment centers worldwide. Communities with competing systems can improve tPA delivery by sharing vascular neurology resources.

Prostate-specific antigen patterns in US and European populations: comparison of six diverse cohorts

OBJECTIVE

To determine whether there are differences in prostate-specific antigen (PSA) levels at diagnosis or changes in PSA levels between US and European populations of men with and without prostate cancer (PCa).

SUBJECTS AND METHODS

We analysed repeated measures of PSA from six clinically and geographically diverse cohorts of men: two cohorts with PSA-detected PCa, two cohorts with clinically detected PCa and two cohorts without PCa. Using multilevel models, average PSA at diagnosis and PSA change over time were compared among study populations.

RESULTS

The annual percentage PSA change of 4-5% was similar between men without cancer and men with PSA-detected cancer. PSA at diagnosis was 1.7 ng/mL lower in a US cohort of men with PSA-detected PCa (95% confidence interval 1.3-2.0 ng/mL), compared with a UK cohort of men with PSA-detected PCa, but there was no evidence of a different rate of PSA change between these populations.

CONCLUSION

We found that PSA changes over time are similar in UK and US men diagnosed through PSA testing and even in men without PCa. Further development of PSA models to monitor men on active surveillance should be undertaken in order to take advantage of these similarities. We found no evidence that guidelines for using PSA to monitor men cannot be passed between US and European studies.

Selenium and Prostate Cancer: Analysis of Individual Participant Data From Fifteen Prospective Studies

BACKGROUND

Some observational studies suggest that a higher selenium status is associated with a lower risk of prostate cancer but have been generally too small to provide precise estimates of associations, particularly by disease stage and grade.

METHODS

Collaborating investigators from 15 prospective studies provided individual-participant records (from predominantly men of white European ancestry) on blood or toenail selenium concentrations and prostate cancer risk. Odds ratios of prostate cancer by selenium concentration were estimated using multivariable-adjusted conditional logistic regression. All statistical tests were two-sided.

RESULTS

Blood selenium was not associated with the risk of total prostate cancer (multivariable-adjusted odds ratio [OR] per 80 percentile increase = 1.01, 95% confidence interval [CI] = 0.83 to 1.23, based on 4527 case patients and 6021 control subjects). However, there was heterogeneity by disease aggressiveness (ie, advanced stage and/or prostate cancer death, Pheterogeneity = .01), with high blood selenium associated with a lower risk of aggressive disease (OR = 0.43, 95% CI = 0.21 to 0.87) but not with nonaggressive disease. Nail selenium was inversely associated with total prostate cancer (OR = 0.29, 95% CI = 0.22 to 0.40, Ptrend < .001, based on 1970 case patients and 2086 control subjects), including both nonaggressive (OR = 0.33, 95% CI = 0.22 to 0.50) and aggressive disease (OR = 0.18, 95% CI = 0.11 to 0.31, Pheterogeneity = .08).

CONCLUSIONS

Nail, but not blood, selenium concentration is inversely associated with risk of total prostate cancer, possibly because nails are a more reliable marker of long-term selenium exposure. Both blood and nail selenium concentrations are associated with a reduced risk of aggressive disease, which warrants further investigation.

FABS

Background and Purpose—

A large number of patients with symptoms of acute cerebral ischemia are stroke mimics (SMs). In this study, we sought to develop a scoring system (FABS) for screening and stratifying SM from acute cerebral ischemia and to identify patients who may require magnetic resonance imaging to confirm or refute a diagnosis of stroke in the emergency setting.

Methods—

We designed a scoring system: FABS (6 variables with 1 point for each variable present): absence of Facial droop, negative history of Atrial fibrillation, Age <50 years, systolic Blood pressure <150 mm Hg at presentation, history of Seizures, and isolated Sensory symptoms without weakness at presentation. We evaluated consecutive patients with symptoms of acute cerebral ischemia and a negative head computed tomography for any acute finding within 4.5 hours after symptom onset in 2 tertiary care stroke centers for validation of FABS.

Results—

A total of 784 patients (41% SMs) were evaluated. Receiver operating characteristic curve (C statistic, 0.95; 95% confidence interval [CI], 0.93–0.98) indicated that FABS≥3 could identify patients with SM with 90% sensitivity (95% CI, 86%–93%) and 91% specificity (95% CI, 88%–93%). The negative predictive value and positive predictive value were 93% (95% CI, 90%–95%) and 87% (95% CI, 83%–91%), respectively.

Conclusions—

FABS seems to be reliable in stratifying SM from acute cerebral ischemia cases among patients in whom the head computed tomography was negative for any acute findings. It can help clinicians consider advanced imaging for further diagnosis.

Changes in blood lymphocyte numbers with age in vivo and their association with the levels of cytokines/cytokine receptors

Background

Alterations in the number and composition of lymphocytes and their subsets in blood are considered a hallmark of immune system aging. However, it is unknown whether the rates of change of lymphocytes are stable or change with age, or whether the inter-individual variations of lymphocyte composition are stable over time or undergo different rates of change at different ages. Here, we report a longitudinal analysis of T- and B-cells and their subsets, and NK cells in the blood of 165 subjects aged from 24 to 90 years, with each subject assessed at baseline and an average of 5.6 years follow-up.

Results

The rates of change of T-(CD4⁺ and CD8⁺) and B-cells, and NK cells were relative stable throughout the adult life. A great degree of individual variations in numbers of lymphocytes and their subsets and in the rates of their changes with age was observed. Among them, CD4⁺ T cells exhibited the highest degree of individual variation followed by NK cells, CD8⁺ T cells, and B cells. Different types of lymphocytes had distinct trends in their rates of change which did not appear to be influenced by CMV infection. Finally, the rates of CD4⁺, CD8⁺ T cells, naive CD4⁺ and naïve CD8⁺ T cells were closely positively correlated.

Conclusion

Our findings provide evidence that the age-associated changes in circulating lymphocytes were at relative stable rates in vivo in a highly individualized manner and the levels of selected cytokines/cytokine receptors in serum might influence these age-associated changes of lymphocytes in circulation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12979-016-0079-7) contains supplementary material, which is available to authorized users.

Ankle proprioceptive acuity is associated with objective as well as self-report measures of balance, mobility, and physical function

Ankle proprioceptive information is integrated by the central nervous system to generate and modulate muscle contractions for maintaining standing balance. This study evaluated the association of ankle joint proprioception with objective and self-report measures of balance, mobility, and physical function across the adult life span. Seven hundred and ninety participants (age range 24-97 years, 362 women) who completed ankle proprioception assessment between 2010 and 2014 were included in the present study from the population-based cohort of the Baltimore Longitudinal Study of Aging (BLSA), USA. Outcome measures included ankle joint proprioception measured as threshold for perception of passive movement (TPPM); single leg stance time; perceived difficulty for standing balance; usual, fastest, and narrow-path gait speed; walking index; short physical performance battery score; and self-reported activity restriction due to fear of falling. Descriptive variables included age, sex, body mass index, education, strength, and cognition. Analyses of covariance (ANCOVA) in general linear model (GLM) or multinomial logistic regression analyses were performed, as appropriate, to test the hypothesis that balance, mobility, and physical function were significantly different according to TPPM quintiles even after adjusting for relevant covariates. Those with TPPM >2.2° consistently demonstrated poor balance, mobility, and physical function. However, with increase in challenge (single leg stance, fastest walking speed, and SPPB), TPPM >1.4° was associated with significantly worse performance. In conclusion, ankle proprioceptive acuity has an overall graded relationship with objective and self-report measures of balance, mobility, and physical function. However, the cutoff proprioceptive acuity associated with substantial decline or inability to perform could depend on the challenge induced.

A Meta-analysis of Individual Participant Data Reveals an Association between Circulating Levels of IGF-I and Prostate Cancer Risk

The role of insulin-like growth factors (IGF) in prostate cancer development is not fully understood. To investigate the association between circulating concentrations of IGFs (IGF-I, IGF-II, IGFBP-1, IGFBP-2, and IGFBP-3) and prostate cancer risk, we pooled individual participant data from 17 prospective and two cross-sectional studies, including up to 10,554 prostate cancer cases and 13,618 control participants. Conditional logistic regression was used to estimate the ORs for prostate cancer based on the study-specific fifth of each analyte. Overall, IGF-I, IGF-II, IGFBP-2, and IGFBP-3 concentrations were positively associated with prostate cancer risk (Ptrend all ≤ 0.005), and IGFBP-1 was inversely associated weakly with risk (Ptrend = 0.05). However, heterogeneity between the prospective and cross-sectional studies was evident (Pheterogeneity = 0.03), unless the analyses were restricted to prospective studies (with the exception of IGF-II, Pheterogeneity = 0.02). For prospective studies, the OR for men in the highest versus the lowest fifth of each analyte was 1.29 (95% confidence interval, 1.16-1.43) for IGF-I, 0.81 (0.68-0.96) for IGFBP-1, and 1.25 (1.12-1.40) for IGFBP-3. These associations did not differ significantly by time-to-diagnosis or tumor stage or grade. After mutual adjustment for each of the other analytes, only IGF-I remained associated with risk. Our collaborative study represents the largest pooled analysis of the relationship between prostate cancer risk and circulating concentrations of IGF-I, providing strong evidence that IGF-I is highly likely to be involved in prostate cancer development. Cancer Res; 76(8); 2288-300. ©2016 AACR.

Aging-Related Considerations When Evaluating the Forced Expiratory Volume in 1 Second (FEV1) Over Time

BACKGROUND

Forced expiratory volume in 1 second (FEV1) over time is commonly expressed in liters and percent predicted (%Pred), or alternatively in L/m(3) and Z-scores-which approach is more clinically meaningful has not been evaluated. Because it uniquely accounts for the effect of aging on FEV1 and spirometric performance, we hypothesized that the Z-score approach is more clinically meaningful, based on associations between cardiopulmonary predictors and FEV1 over time.

METHODS

Using linear mixed-effects models and data from the Baltimore Longitudinal Study on Aging, including 501 white participants aged 40-95 who had completed at least three longitudinal spirometric assessments, we evaluated the associations between cardiopulmonary predictors (obesity, smoking status, hypertension, chronic bronchitis, diabetes mellitus, and myocardial infarction) and FEV1 over time, in liters, %Pred, L/m(3), and Z-scores.

RESULTS

Mean baseline values for FEV1 were 3.240L, 96.4%Pred, 0.621L/m(3), and -0.239 as a Z-score (40.6th percentile). The annual decline in FEV1 was 0.040L, 0.234 %Pred, 0.007L/m(3), and 0.008 Z-score units. Baseline age was associated with FEV1 over time in liters and L/m(3) (p < .001), and included a time interaction for %Pred (p < .001), but was not associated with Z-scores (p = .933). The associations of cardiopulmonary predictors with FEV1 over time were all significant when using Z-scores (p < .05), but varied for other methods of expressing FEV1.

CONCLUSION

A Z-score approach is more clinically meaningful when evaluating FEV1 over time, as it accounted for the effect of aging and was more frequently associated with multiple cardiopulmonary predictors.

Telomere Length as an Indicator of the Robustness of B- and T-Cell Response to Influenza in Older Adults

BACKGROUND

Telomeres provide a key mechanism for protecting the integrity of chromosomes and their attrition after cell division and during aging are evident in lymphocytes. However, the significance of telomere shortening in age-associated decline of immune function is unknown.

METHODS

We selected 22 HLA-A2-positive healthy older adults who have relatively short or long telomere lengths to compare their antibody response against the influenza vaccine, and their CD8(+) T-cell response against an influenza antigen.

RESULTS

B cells from individuals with a robust antibody response to the influenza vaccine had significantly longer telomeres than those with a poor antibody response. Monocyte-derived antigen-presenting cells of both short and long telomere groups induced similar expansions of influenza M1-specific CD8(+) T cells. Vaccination did not increase M1-specific CD8(+) T cells in blood, but M1-specific CD8(+) T cells from the long telomere group exhibited significantly greater expansion in vitro than those from the short telomere group. Finally, M1-specific CD8(+) T cells that underwent more expansions had significantly longer telomeres than cells with fewer divisions.

CONCLUSIONS

Telomere length is positively associated with a robust lymphocyte response, and telomere attrition may contribute to the age-associated decline of adaptive immunity.

TCRβ repertoire of CD4+ and CD8+ T cells is distinct in richness, distribution, and CDR3 amino acid composition

The TCR repertoire serves as a reservoir of TCRs for recognizing all potential pathogens. Two major types of T cells, CD4(+) and CD8(+), that use the same genetic elements and process to generate a functional TCR differ in their recognition of peptide bound to MHC class II and I, respectively. However, it is currently unclear to what extent the TCR repertoire of CD4(+) and CD8(+) T cells is different. Here, we report a comparative analysis of the TCRβ repertoires of CD4(+) and CD8(+) T cells by use of a 5' rapid amplification of cDNA ends-PCR-sequencing method. We found that TCRβ richness of CD4(+) T cells ranges from 1.2 to 9.8 × 10(4) and is approximately 5 times greater, on average, than that of CD8(+) T cells in each study subject. Furthermore, there was little overlap in TCRβ sequences between CD4(+) (0.3%) and CD8(+) (1.3%) T cells. Further analysis showed that CD4(+) and CD8(+) T cells exhibited distinct preferences for certain amino acids in the CDR3, and this was confirmed further by a support vector machine classifier, suggesting that there are distinct and discernible differences between TCRβ CDR3 in CD4(+) and CD8(+) T cells. Finally, we identified 5-12% of the unique TCRβs that share an identical CDR3 with different variable genes. Together, our findings reveal the distinct features of the TCRβ repertoire between CD4(+) and CD8(+) T cells and could potentially be used to evaluate the competency of T cell immunity.

Detection of a novel, integrative aging process suggests complex physiological integration

Many studies of aging examine biomarkers one at a time, but complex systems theory and network theory suggest that interpretations of individual markers may be context-dependent. Here, we attempted to detect underlying processes governing the levels of many biomarkers simultaneously by applying principal components analysis to 43 common clinical biomarkers measured longitudinally in 3694 humans from three longitudinal cohort studies on two continents (Women's Health and Aging I & II, InCHIANTI, and the Baltimore Longitudinal Study on Aging). The first axis was associated with anemia, inflammation, and low levels of calcium and albumin. The axis structure was precisely reproduced in all three populations and in all demographic sub-populations (by sex, race, etc.); we call the process represented by the axis "integrated albunemia." Integrated albunemia increases and accelerates with age in all populations, and predicts mortality and frailty--but not chronic disease--even after controlling for age. This suggests a role in the aging process, though causality is not yet clear. Integrated albunemia behaves more stably across populations than its component biomarkers, and thus appears to represent a higher-order physiological process emerging from the structure of underlying regulatory networks. If this is correct, detection of this process has substantial implications for physiological organization more generally.

Age-associated telomere attrition of lymphocytes in vivo is co-ordinated with changes in telomerase activity, composition of lymphocyte subsets and health conditions

Telomeres are essential in maintaining chromosome integrity and in controlling cellular replication. Attrition of telomere length in peripheral blood mononuclear cells (PBMCs) with age is well documented from cross-sectional studies. But the actual in vivo changes in telomere lengths and its relationship with the contributing factors within the individuals with age have not been fully addressed. In the present paper, we report a longitudinal analysis of telomere length in the PBMCs, lymphocytes and monocytes of 216 human subjects aged from 20-90 years assessed at 0-, 5- and 12-year follow-up. For the 5- and 12-year follow-up, telomere length in the PBMCs decreased in 34% and 46%, exhibited no detectable change in 56% and 47% and increased in 10% and 7% of the subjects respectively. The rate of telomere change was distinct for T-cells, B-cells and monocytes for any given subject. Telomerase activity declined with age in the resting T-cells and B-cells and the activated T-cells. Finally, a significant portion of telomere attrition in T-cells with age was explained by a decline in the telomerase activity, decreased naïve cells and the change in physiological conditions such as elevated blood glucose and interleukin (IL)-6 levels. These findings show that changes in the telomere length of the PBMCs with age in vivo occur at different rates in different individuals and cell types and reveal that changes in the telomere length in the T-cells with age is influenced by the telomerase activity, naïve T-cell percentage and changes in health conditions.

Hyperglycemia predicts persistently lower muscle strength with aging

OBJECTIVE

Persons with diabetes have accelerated muscle loss compared with their counterparts. The relationship of hyperglycemia per se to declines in muscle function has not been explored yet has implications for developing appropriate intervention strategies to prevent muscle loss.

RESEARCH DESIGN AND METHODS

We examined 984 participants aged 25-96 years in the Baltimore Longitudinal Study of Aging (2003-2011) with HbA1c, knee extensor strength (isokinetic dynamometer), and lean body mass (DEXA) measured at baseline. Participants had repeated measurements up to 7.5 years later. Muscle quality was defined as knee extensor strength/leg lean mass. Participants were categorized by HbA1c quartile (<5.5, 5.5-5.79, 5.8-6.09, and ≥6.1% or <37, 37-40, 40-43, and ≥43 mmol/mol). Mixed-effects regression models were used to examine the regression of muscle outcomes on HbA1c.

RESULTS

Muscle strength and quality were significantly lower across HbA1c quartiles (both P < 0.001), without differences in muscle mass at baseline. Comparing highest versus lowest HbA1c quartiles and adjusting for age, race, sex, weight, and height, strength was significantly lower (-4.70 ± 2.30 N · m; P value trend = 0.02) and results were unchanged after adjustment for physical activity (P value trend = 0.045) but of borderline significance after additional adjustment for peripheral neuropathy (P value trend = 0.05). Adjusting for demographics, muscle quality was significantly lower (-0.32 ± 0.15 N · m/kg; P value trend = 0.02) in the highest versus lowest HbA1c quartiles, but differences were attenuated after adjusting for weight and height (-0.25 ± 0.15 N · m/kg; P value trend = 0.07). Muscle mass measures were similar across HbA1c quartiles.

CONCLUSIONS

Hyperglycemia is associated with persistently lower muscle strength with aging, but this effect may be mediated, at least in part, by peripheral neuropathy. Future studies should explore if better glycemic control can preserve muscle function in diabetes.

Cost effectiveness of two army physical fitness programs

Repeated failure in the Army Physical Fitness Test (APFT) is associated with lower fitness level, premature discharge, and significant career disruption, at high economic and health costs to the individual soldier and the U.S. Army. We used cost-effectiveness analysis to estimate the health and economic implications of two exercise interventions for Army National Guard (ARNG) soldiers who had failed the APFT, a traditional remediation program and a new pedometer-based program called Fitness for Life, involving individual counseling and follow-up telephone calls. Effectiveness of the interventions was analyzed in terms of APFT pass rates and calculated 10-year coronary heart disease risk. Costs were calculated based on tracking of resources used in the programs. APFT pass rates were 54.3% and 47.9%, respectively, for traditional and Fitness for Life programs, p = not significant. Neither program affected 10-year coronary heart disease risk. For assumed APFT pass rates up to 40% without any formal remediation, both the traditional remediation program and the ARNG Fitness for Life intervention had cost savings without significant group differences. Depending on the ARNG unit and personnel preference, although the Fitness for Life Program was more expensive and thus less cost-effective, either program could be cost-effective and of benefit to the military.

Association of hearing impairment with brain volume changes in older adults

Hearing impairment in older adults is independently associated in longitudinal studies with accelerated cognitive decline and incident dementia, and in cross-sectional studies, with reduced volumes in the auditory cortex. Whether peripheral hearing impairment is associated with accelerated rates of brain atrophy is unclear. We analyzed brain volume measurements from magnetic resonance brain scans of individuals with normal hearing versus hearing impairment (speech-frequency pure tone average>25 dB) followed in the neuroimaging substudy of the Baltimore Longitudinal Study of Aging for a mean of 6.4 years after the baseline scan (n=126, age 56-86 years). Brain volume measurements were performed with semi-automated region-of-interest (ROI) algorithms, and brain volume trajectories were analyzed with mixed-effect regression models adjusted for demographic and cardiovascular factors. We found that individuals with hearing impairment (n=51) compared to those with normal hearing (n=75) had accelerated volume declines in whole brain and regional volumes in the right temporal lobe (superior, middle, and inferior temporal gyri, parahippocampus, p<.05). These results were robust to adjustment for multiple confounders and were consistent with voxel-based analyses, which also implicated right greater than left temporal regions. These findings demonstrate that peripheral hearing impairment is independently associated with accelerated brain atrophy in whole brain and regional volumes concentrated in the right temporal lobe. Further studies investigating the mechanistic basis of the observed associations are needed.

Difference in muscle quality over the adult life span and biological correlates in the Baltimore Longitudinal Study of Aging

OBJECTIVES

To examine differences in a proxy measure of muscle quality across the adult life span and explore potential mechanisms of muscle quality change through identification of cross-sectional correlates of muscle quality.

DESIGN

Cross-sectional study.

SETTING

Baltimore Longitudinal Study of Aging.

PARTICIPANTS

Seven hundred eighty-six individuals with a mean age of 66.3 (range 26-96) (N = 786). A sensitivity analysis was conducted in a subset of participants matched according to sex, muscle mass, and body size.

MEASUREMENTS

Muscle quality was operationalized as the ratio of knee-extension strength (isokinetic dynamometry) to thigh muscle cross-sectional area (computed tomography). Differences in muscle strength, muscle area, and muscle quality ratio with age were evaluated, and the association between the muscle quality ratio and measures reflecting domains of cognitive function, motor control, peripheral nerve function, adiposity, glucose homeostasis, and inflammation were assessed through multivariate regression analyses.

RESULTS

A linear relationship between age and muscle quality ratio was observed, suggesting a gradual decline in muscle quality over the adult life course. Associations were observed between muscle quality ratio and measures of adiposity, as well as peroneal nerve motor conduction velocity, finger tapping speed, and memory performance (P < .01). The association between muscle quality ratio and nerve conduction velocity was maintained after adjustment for anthropometric measurements (P < .05).

CONCLUSION

Muscle quality declines progressively with age over the adult life span and is affected by obesity and neurological factors. Studies are needed to clarify the mechanisms of these associations and their implications for functional outcomes.