A socially-engaged lifestyle moderates the association between gait velocity and cognitive impairment.

Objective: Cognitive status has been linked to impaired gait velocity, and diminished social and physical engagement. To date, the potential moderating influence of lifestyle engagement on gait-cognitive status associations has not been systematically explored. The present investigation examines whether a socially- or physically-engaged lifestyle moderates the association between diminished gait velocity and likelihood of amnestic mild cognitive impairment (a-MCI) classification.Methods: Participants (aged 65+, Mage=73 years) were classified as either healthy controls (n = 30) or a-MCI (n = 24), using neuropsychological test scores and clinical judgement. Gait velocity was indexed using a GAITRite computerized walkway, engaged lifestyle (social and physical subdomains) were measured using a well-validated self-report measure, the revised Activity Lifestyle Questionnaire.Results: Logistic regression, evaluating likelihood of a-MCI classification, yielded a significant interaction between a socially-engaged lifestyle and gait velocity (b=.01, SE=.003, p=.015). Follow-up simple effects were derived for two levels (+/-1SD) of social engagement; for individuals 1 SD below the mean, the association between gait velocity and increased likelihood of a-MCI classification was exacerbated (probability of a-MCI classification for those with slower gait velocity was 60% higher for individuals 1 SD below vs 1 SD above the mean of social engagement). Physically-engaged lifestyle did not significantly moderate the gait-cognitive status association.Conclusions: The significant moderating influence of social engagement has several implications, including the likelihood that distinct mechanisms underlie the relationships of social engagement and gait velocity to cognitive function, the value of social variables for well-being, and the potential utility of socially-based interventions that may prevent/delay a-MCI onset.

Intraindividual Variability across Neuropsychological Tests: Dispersion and Disengaged Lifestyle Increase Risk for Alzheimer's Disease.

Objective: Increased intraindividual variability (IIV) in function has been linked to various age-related outcomes including cognitive decline and dementia. Most studies have operationalized IIV as fluctuations across trials (e.g., response latencies) for a single task, with comparatively few studies examining variability across multiple tasks for a given individual. In the present study, we derive a multivariable operationalization of dispersion across a broad profile of neuropsychological measures and use this index along with degree of engaged lifestyle to predict risk of cognitive impairment. Participants and Methods: Participants (n = 60) were community-dwelling older adults aged 65+ years (M = 74.1, SD = 6.5) participating in a cross-sectional investigation of risk factors for amnestic mild cognitive impairment (a-MCI) and probable Alzheimer's Disease (AD). Participants were classified into three subgroups based on test performance and clinical judgement. Healthy controls (n = 30) scored better than -1 SD relative to existing norms on all classification measures, in the absence of memory complaints or functional impairments. The a-MCI group (n = 23) had self- or informant-reported memory complaints and scored 1 SD or more below the mean for at least one memory task while scoring better than 1 SD below the mean for all other cognitive domains, in the absence of functional impairments. The AD group (n = 7) scored at least 2 SD below the mean for two cognitive domains (including memory) with impairments in functioning. Measures spanned a range of cognitive domains (episodic memory, executive function, language), with the derived dispersion estimates reflecting variability across an individual's neuropsychological profile relative to the group average. Further, an Activities Lifestyle Questionnaire, indexing social, cognitive, and physical behaviors, was administered to assess the protective benefits of engaged lifestyle. Results: Multinomial logistic regression models examined the risk of being classified as a-MCI or AD as a function of increased dispersion, (dis)engaged lifestyle, and their interaction. Greater dispersion was associated with an increased likelihood of being classified with AD, with protective engaged-lifestyle benefits apparent for a-MCI individuals only. Conclusion: As a measure of IIV, dispersion across neuropsychological profiles holds promise for the detection of cognitive impairment.

Concurrent Indicators of Gait Velocity and Variability Are Associated with 25-Year Cognitive Change: A Retrospective Longitudinal Investigation.

Background/Objectives: Physical function indicators, including gait velocity, stride time and step length, are linked to neural and cognitive function, morbidity and mortality. Whereas cross-sectional associations are well documented, far less is known about long-term patterns of cognitive change as related to objective indicators of mobility-related physical function. Methods: Using data from the Victoria Longitudinal Study, a long-term investigation of biological and health aspects of aging and cognition, we examined three aspects of cognition-physical function linkages in 121 older adults. First, we examined a simple marker of physical function (3 m timed-walk) as a predictor of cross-sectional differences and up to 25-year change for four indicators of cognitive function. Second, we tested associations between two markers of gait function derived from the GAITRite system (velocity and stride-time variability) and differences and change in cognition. Finally, we evaluated how increasing cognitive load during GAITRite assessment influenced the associations between gait and cognition. Results: The simple timed-walk measure, commonly used in clinical and research settings, was a minor predictor of change in cognitive function. In contrast, the objectively measured indicator of walking speed significantly moderated long-term cognitive change. Under increasing cognitive load, the moderating influence of velocity on cognitive change increased, with increasing variability in stride time also emerging as a predictor of age-related cognitive decline. Conclusion: These findings: (a) underscore the utility of gait as a proxy for biological vitality and for indexing long-term cognitive change; and (b) inform potential mechanisms underlying age-related linkages in physical and cognitive function.

Vascular Health and Genetic Risk Affect Mild Cognitive Impairment Status and 4-Year Stability: Evidence From the Victoria Longitudinal Study.

OBJECTIVES: Mild cognitive impairment (MCI) is a high-risk condition for progression to Alzheimer's disease (AD). Vascular health is a key mechanism underlying age-related cognitive decline and neurodegeneration. AD-related genetic risk factors may be associated with preclinical cognitive status changes. We examine independent and cross-domain interactive effects of vascular and genetic markers for predicting MCI status and stability. METHOD: We used cross-sectional and 2-wave longitudinal data from the Victoria Longitudinal Study, including indicators of vascular health (e.g., reported vascular diseases, measured lung capacity and pulse rate) and genetic risk factors-that is, apolipoprotein E (APOE; rs429358 and rs7412; the presence vs absence of ε4) and catechol-O-methyltransferase (COMT; rs4680; met/met vs val/val). We examined associations with objectively classified (a) cognitive status at baseline (not impaired congnitive (NIC) controls vs MCI) and (b) stability or transition of cognitive status across a 4-year interval (stable NIC-NIC vs chronic MCI-MCI or transitional NIC-MCI). RESULTS: Using logistic regression, indicators of vascular health, both independently and interactively with APOE ε4, were associated with risk of MCI at baseline and/or associated with MCI conversion or MCI stability over the retest interval. DISCUSSION: Several vascular health markers of aging predict MCI risk. Interactively, APOE ε4 may intensify the vascular health risk for MCI.

BioAge: toward a multi-determined, mechanistic account of cognitive aging.

The search for reliable early indicators of age-related cognitive decline represents a critical avenue for progress in aging research. Chronological age is a commonly used developmental index; however, it offers little insight into the mechanisms underlying cognitive decline. In contrast, biological age (BioAge), reflecting the vitality of essential biological systems, represents a promising operationalization of developmental time. Current BioAge models have successfully predicted age-related cognitive deficits. Research on aging-related cognitive function indicates that the interaction of multiple risk and protective factors across the human lifespan confers individual risk for late-life cognitive decline, implicating a multi-causal explanation. In this review, we explore current BioAge models, describe three broad yet pathologically relevant biological processes linked to cognitive decline, and propose a novel operationalization of BioAge accounting for both moderating and causal mechanisms of cognitive decline and dementia. We argue that a multivariate and mechanistic BioAge approach will lead to a greater understanding of disease pathology as well as more accurate prediction and early identification of late-life cognitive decline.

APOE and COMT polymorphisms are complementary biomarkers of status, stability, and transitions in normal aging and early mild cognitive impairment.

OBJECTIVE: Research has reported associations among selected genetic susceptibility biomarkers and risk of (a) normal cognitive aging decrements, (b) established mild cognitive impairment (MCI), and (c) sporadic Alzheimer's disease (AD). In focusing on the transitional normal-to-early MCI phase, we examine associations among three theoretically relevant polymorphisms (APOE [rs429358, rs7412], BDNF [rs6265], COMT [rs4680]) and both baseline cognitive status (MCI vs. normal aging) and two-wave (four-year) longitudinal stability or change profiles. The latter included three profiles: (a) stable as normal aging, (b) stable or chronic impairment (MCI-to-MCI), and (c) emergence of impairment (normal-to-MCI). METHOD: Genotyped older adults (n = 237 at baseline; age range = 64-91; 62% women) from the Victoria Longitudinal Study were examined for (a) independent and interactive associations of three genetic polymorphisms with (b) two objectively classified cognitive status groups (not-impaired controls (NIC) and MCI) at (c) both baseline and across a two-wave (four-year) longitudinal interval. RESULTS: First, logistic regression revealed that the presence of at least one APOE ε4 allele (the risk factor for AD) was linked to greater baseline risk of objective MCI. Second, multinomial logistic regression revealed that (a) the presence of an APOE ε4 allele was associated with an increased risk of 4-year MCI status stability (chronicity), and (b) the COMT homozygous risk genotype (G/G or Val/Val) was associated with an increased risk of both MCI-to-MCI stability (chronicity) and emerging NIC-to-MCI conversion. DISCUSSION: Both chronicity and emergence of objectively classified early cognitive impairment may be genetically heterogeneous phenomena, with influences from a panel of both normal cognitive aging (COMT) and AD-related (APOE) polymorphisms.

Toll-like receptor transcriptome in the HPV-positive cervical cancer microenvironment.

The human papillomavirus (HPV) directly infects cervical keratinocytes and interferes with TLR signalling. To shed light on the effect of HPV on upstream receptors, we evaluated TLRs 1-9 gene expression in HPV-negative normal and HPV-positive pre-malignant and malignant ex vivo cervical tissue. Quantitative real-time polymerase chain reaction was performed separately for epithelial and stromal tissue compartments. Differences in gene expression were analyzed by the Jonckheere-Terpstra trend test or the Student's t-test for pairwise comparison. Laser capture microdissection revealed an increase in TLR3 and a decrease in TLR1 mRNA levels in dysplastic and carcinoma epithelium, respectively. In the stroma, a trend of increasing TLR 1, 2, 5, 6, and 9 mRNA levels with disease severity was found. These findings implicate the involvement of TLR3 and TLR1 in early and late cervical carcinogenesis, respectively, suggesting that stromal upregulation of TLRs may play a role in cervical disease progression.

Expression of integrins and Toll-like receptors in cervical cancer: effect of infectious agents.

We hypothesized that development of cervical cancer is associated with alterations in the expression of innate immune receptors, i.e. integrins and TLRs, and that these alterations can be induced by infectious agents. We have studied the expression of these proteins in cervical biopsy tissues and cervical cancer-derived cell lines HeLa, CaSki, SiHa, C-33 A, and ME180. Immunohistochemistry analysis demonstrated an increase in integrin αv, ß3, ß4, and ß6 expression in the epithelium during the development of cervical cancer. A clear trend towards higher expression of integrin ß6 in cell lines harbouring human papillomavirus (HPV) genetic material, compared to HPV-negative C-33 A, was observed. To investigate whether bacterial infection can alter the expression of TLRs and integrins, we infected HeLa cells by two pathogens, Escherichia coli and Pseudomonas aeruginosa, using a common bacterium of the female genital tract, Lactobacillus reuteri, as a control. Infection with E. coli or P. aeruginosa, but not with L. reuteri, significantly altered the expression of TLR and integrins, particularly of TLR4 and integrin ß6. Considering that both integrin ß6 and TLR4 play important roles in tumorigenesis, our data suggest that bacterial infection may trigger cancer development in HPV-infected cervical epithelium.

Linking biological and cognitive aging: toward improving characterizations of developmental time.

OBJECTIVES: Chronological age is the most frequently employed predictor in life-span developmental research, despite repeated assertions that it is best conceived as a proxy for true mechanistic changes that influence cognition across time. The present investigation explores the potential that selected functional biomarkers may contribute to the more effective conceptual and operational definitions of developmental time. METHODS: We used data from the Victoria Longitudinal Study to explore both static and dynamic biological or physiological markers that arguably influence process-specific mechanisms underlying cognitive changes in late life. Multilevel models were fit to test the dynamic coupling between change in theoretically relevant biomarkers (e.g., grip strength, pulmonary function) and change in select cognitive measures (e.g., executive function, episodic and semantic memory). RESULTS: Results showed that, independent of the passage of developmental time (indexed as years in study), significant time-varying covariation was observed linking corresponding declines for select cognitive outcomes and biological markers. DISCUSSION: Our findings support the interpretation that cognitive decline is not due to chronological aging per se but rather reflects multiple causal factors from a broad range of biological and physical health domains that operate along the age continuum.

IFN-κ, a novel type I IFN, is undetectable in HPV-positive human cervical keratinocytes.

Interferons (IFNs) are expressed by many cell types and play a pivotal role in the generation of immune responses against viral infections. IFN-κ, a novel type I IFN, displays a tight tropism for keratinocytes and specific lymphoid populations and exhibits functional similarities with other type I IFNs. The human papillomavirus (HPV), the etiological agent for cervical cancer, infects keratinocytes of the uterine cervix and has been shown to directly inhibit the IFN pathway. We evaluated IFN-κ, -ß, and -γ gene expression in HPV-negative normal and HPV-positive pre-malignant and malignant ex vivo cervical tissue covering the entire spectrum of cervical disease. Quantitative real-time polymerase chain reaction and methods previously optimized for detecting low-expressing genes in cervical tissue were used. In contrast to IFN-ß and -γ, IFN-κ mRNA prevalence and levels were unexpectedly higher in diseased compared with normal whole cervical tissue with highest levels observed in invasive carcinoma tissue. Strikingly, laser capture microdissection revealed an absence of IFN-κ mRNA in diseased epithelium, whereas stromal IFN-κ was found exclusively in diseased tissue. IFN-γ and IFN-ß were likewise found to be upregulated in diseased cervical stroma. Immunofluorescence supports the involvement of monocytes and dendritic cells in the stromal induction of IFNs in diseased tissue. Further, using three-dimensional raft cultures in which the viral life cycle can be mimicked, human keratinocytes transfected with full-length HPV16 displayed a significant decrease in IFN-κ mRNA compared with non-transfected human keratinocytes. Altogether, these findings show that IFN-κ is down-regulated in cervical keratinocytes harboring HPV, which may be a contributing factor in the progression of a cervical lesion.

Human papillomavirus 16 E6 variants differ in their dysregulation of human keratinocyte differentiation and apoptosis.

L83V-related variants of human papillomavirus (HPV) 16 E6, exemplified by the Asian-American variant Q14H/H78Y/L83V, were shown to be more prevalent than E6 prototype in progressing lesions and cervical cancer. We evaluated functions relevant to carcinogenesis for the E6 variants L83V, R10/L83V and Q14H/H78Y/L83V as well as the prototype in a model of human normal immortalized keratinocytes (NIKS). All E6 expressing NIKS equally abrogated growth arrest and DNA damage responses. Organotypic cultures derived from these keratinocytes demonstrated hyperplasia and aberrantly expressed keratin 5 in the suprabasal compartment. In contrast, differentiation and induction of apoptosis varied. The E6 variant rafts expressed keratin 10 in nearly all suprabasal cells while the prototype raft showed keratin 10 staining in a subset of suprabasal cells only. In addition, E6 variant NIKS expressing R10G/L83V and Q14H/H78Y/L83V were more prone to undergo cell-detachment-induced apoptosis (anoikis) than NIKS expressing E6 prototype. The combined differentiation and apoptosis pattern of high-risk E6 variants, especially of Q14H/H78Y/L83V, may reflect a phenotype beneficial to carcinogenesis and viral life cycle.

Gene expression analysis of interferon kappa in laser capture microdissected cervical epithelium.

Optimal sample handling techniques for tissue preparation and storage, RNA extraction and quantification, and target gene detection are crucial for reliable gene expression analysis. Methods for measuring low-expressing genes, such as interferons, in human cervical samples are not described in the scientific literature. To detect interferon mRNA in human cervical samples we obtained normal and dysplastic frozen and formalin-fixed cervical biopsies from colposcopy. Histopathological diagnosis was performed by one pathologist. Cervical keratinocytes were isolated using laser capture microdissection. Immortalized keratinocytes transduced with or devoid of an HPV oncogene were used for initial method development. RNA from samples was extracted and integrity tested to compare tissue storage and extraction methods. The expression of five housekeeping genes was analyzed in cell lines and patient tissue to permit normalization between samples using quantitative real-time polymerase chain reaction. The usefulness of cDNA amplification was assessed for the detection of low-expressing interferon kappa in cervical tissue. Here we report optimal tissue storage conditions, RNA extraction, sample normalization, and transcript amplification, as well as the sensitivity of quantitative real-time polymerase chain reaction and laser capture microdissection, for interferon kappa detection in cervical tissue. Without these optimized techniques, interferon kappa detection would be unattainable in cervical samples.

Temperature-sensitive gating in a descending visual interneuron, DCMD.

Activity in neural circuits can be modified through experience-dependent mechanisms. The effects of high temperature on a locust visual interneuron (the descending contralateral movement detector, DCMD) have previously been shown to be mitigated by prior exposure to sub-lethal, elevated temperatures (heat shock, HS). Activity in the DCMD is reduced at high temperature in naïve animals (control), whereas HS animals show a maintained spike count at all temperatures. We examined whether this finding was due to direct effects of temperature on visual processing, or whether other indirect feedback mechanisms were responsible for the observed effect in the DCMD. Activity in the DCMD was elicited using a computer-generated looming image, and the response was recorded extracellularly. The temperature of visual processing circuits contributes directly to HS-induced plasticity in the DCMD, as maintaining the brain at 25 degrees C during a thoracic temperature ramp eliminated the high frequency activity associated with HS. Removing ascending input by severing the thoracic nerve cord reduced DCMD thermosensitivity, indicating that indirect feedback mechanisms are also involved in controlling the DCMD response to increased thoracic temperature. Understanding how thermosensitive feedback within the locust affects DCMD function provides insight into critical regulatory mechanisms underlying visually-guided behaviors.