Carrie J. Merkle

CAREGIVING STRESS, IMMUNE FUNCTION, AND HEALTH: IMPLICATIONS FOR RESEARCH WITH PARENTS OF MEDICALLY FRAGILE CHILDREN

Caregiving stress has been associated with considerable demands imposed on parents responsible for the physical and emotional care of medically fragile children. With health care advances in medicine and technology, there are a growing number of children with chronic conditions and disabilities (i.e., the medically fragile) surviving longer and being cared for almost exclusively in the home by parents. The physical strains, financial constraints, emotional effects, and social isolation experienced by parents caring for children with such complex medical needs may ultimately impact their physical and emotional health. Stress associated with the caregiving of older adults has been shown to negatively impact on health and immune functioning with the potential for associated morbidity. Studies exploring the relationship of stress with biological markers of immune functioning in parents have not been widely conducted. Therefore, there is a great opportunity in parent-child health for researchers to investigate implications of stress on immune functioning and health outcomes in parents caring for medically fragile children at home. The purpose of this review article will be to provide an overview of the literature related to caregiving stress and immune functioning and to discuss implications for research in this area with parents of medically fragile children.

Structural and functional effects of high prolactin levels on injured endothelial cells: Evidence for an endothelial prolactin receptor

Stress has been linked to health problems such as atherosclerosis and prolonged wound healing, which involve the responses of injured endothelial cells. Though prolactin (PRL) levels become increased during the physiological response to stress, the significance and effects of these increases are largely unknown. Here we examined the effects of elevated, though physiological, concentrations of PRL on the responses of cultured endothelial cells after mechanical injury to cell monolayers. When treated at the time of injury with PRL levels of 62.5–1000 ng/mL, cells at the wound front became abnormal in shape and had reductions in f-actin staining in comparison to controls that were not PRL-treated. High PRL concentrations also inhibited the adhesion of cells to their growth surface in a dose-dependent manner. Using rhodamine-labeled PRL, we observed specific PRL uptake by these cells that suggested the presence of a PRL receptor. Finally, mRNA for the long form of the PRL receptor was detected by RT-PCR. To our knowledge, this is the first report demonstrating that (1) high PRL concentrations alter the actin cytoskeleton and adhesion of injured endothelial cells and (2) endothelial cells express the transcript for the PRL receptor. Thus, we report novel effects of PRL that may be mediated by activation of an endothelial cell PRL receptor.

Methotrexate causes apoptosis in postmitotic endothelial cells.

Methotrexate (MTX) is a commonly used chemotherapy agent for a variety of cancers. However, therapeutic levels are associated with numerous untoward effects such as central nervous system damage in children with acute lymphoblastic leukemia. The purpose of this study was to determine if MTX caused injury to endothelial cells using cultured bovine pulmonary artery endothelial cells as a model. Light microscopy showed gaps between cells and reduced numbers of endothelial cells after exposure to MTX (10 M), a range consistent with therapeutic drug levels. Proliferation and viability of subconfluent and confluent MTX-treated endothelial cells were measured by colorimetric (MTS) assay. There was a significant decline in cell numbers in MTX-treated subconfluent (growing) cells cultured after 4 days of MTX exposure compared to controls, as expected. However, there was also an unexpected decline in cell numbers in MTX-treated postmitotic endothelial cells after 1, 3, and 4 days of drug exposure. This suggested that MTX induced endothelial cell death. Fluorescent ApoAlert™ Enhanced Annexin-V binding demonstrated apoptosis in endothelial cells after 1 day of MTX exposure. Apoptosis was confirmed by a DNA fragment assay. This is apparently the first report of MTX-induced apoptosis of postmitotic, cultured endothelial cells. The findings suggest that apoptosis may be one mechanism of MTX-induced injury to endothelial cells.

Current and Emerging Technology Approaches in Genomics

PURPOSE To introduce current and emerging approaches that are being utilized in the field of genomics so the reader can conceptually evaluate the literature and appreciate how these approaches are advancing our understanding of health-related issues. ORGANIZING CONSTRUCT Each approach is described and includes information related to how it is advancing research, its potential clinical utility, exemplars of current uses, challenges related to technologies used for these approaches, and when appropriate information related to understanding the evidence base for clinical utilization of each approach is provided. Web-based resources are included for the reader who would like more in-depth information and to provide opportunity to stay up to date with these approaches and their utility. CONCLUSIONS The chosen approaches-genome sequencing, genome-wide association studies, epigenomics, and gene expression-are extremely valuable approaches for collecting research data to help us better understand the pathophysiology of a variety of health-related conditions, but they are also gaining in utility for clinical assessment and testing purposes. CLINICAL RELEVANCE Our increased understanding of the molecular underpinnings of disease will assist with better development of screening tests, diagnostic tests, tests that allow us to prognosticate, tests that allow for individualized treatments, and tests to facilitate post-treatment surveillance.

Weight change during childhood acute lymphoblastic leukemia induction therapy predicts obesity: A report from the Children's Oncology Group

Obesity is a well documented problem associated with childhood acute lymphoblastic leukemia (ALL) with increasing body mass index often observed during therapy. This study aims to evaluate if weight gain, early in therapy, is predictive of obesity at the end of treatment.

Age-related differences in cigarette smoke extract-induced H2O2 production by lung endothelial cells

Cigarette smoke causes oxidative stress in the lung resulting in injury and disease. The purpose of this study was to determine if there were age-related differences in cigarette smoke extract (CSE)-induced production of reactive species in single and co-cultures of alveolar epithelial type I (AT I) cells and microvascular endothelial cells harvested from the lungs (MVECLs) of neonatal, young and old male Fischer 344 rats. Cultures of AT I cells and MVECLs grown separately (single culture) and together (co-culture) were exposed to CSE (1, 10, 50, 100%). Cultures were assayed for the production of intracellular reactive oxygen species (ROS), hydroxyl radical (OH), peroxynitrite (ONOO(-)), nitric oxide (NO) and extracellular hydrogen peroxide (H(2)O(2)). Single and co-cultures of AT I cells and MVECLs from all three ages produced minimal intracellular ROS in response to CSE. All ages of MVECLs produced H(2)O(2) in response to CSE, but young MVECLs produced significantly less H(2)O(2) compared to neonatal and old MVECLs. Interestingly, when grown as a co-culture with age-matched AT I cells, neonatal and old MVECLs demonstrated ~50% reduction in H(2)O(2) production in response to CSE. However, H(2)O(2) production in young MVECLs grown as a co-culture with young AT I cells did not change with CSE exposure. To begin investigating for a potential mechanism to explain the reduction in H(2)O(2) production in the co-cultures, we evaluated single and co-cultures for extracellular total antioxidant capacity. We also performed gene expression profiling specific to oxidant and anti-oxidant pathways. The total antioxidant capacity of the AT I cell supernatant was ~5 times greater than that of the MVECLs, and when grown as a co-culture and exposed to CSE (≥ 10%), the total antioxidant capacity of the supernatant was reduced by ~50%. There were no age-related differences in total antioxidant capacity of the cell supernatants. Gene expression profiling found eight genes to be significantly up-regulated or down-regulated. This is the first study to describe age-related differences in MVECLs exposed to CSE.

High perceived stress is linked to afternoon cortisol levels and greater symptom distress in patients with localized prostate cancer.

Background: Patients treated with radical prostatectomy (RP) or radiation therapy (RT) for prostate cancer can experience stress and symptoms that impact quality of life. Objective: The objectives of this study were to describe cortisol levels, perceived stress, symptoms, and symptom distress; compare differences in variables measured between RP and RT; and identify associations among cortisol levels, perceived stress, symptoms, and symptom distress in patients treated for localized prostate cancer. Methods: A descriptive, cross-sectional study was conducted with 53 patients (RP n = 24, RT n = 29). Data from saliva, questionnaires, and interviews were collected within 3 months of treatment. Saliva samples were collected at 4 times over 2 consecutive days. Data were analyzed using descriptive statistics, correlations, and regressions. Results: A robust diurnal rhythm of cortisol secretion with heightened levels in the early morning and lowered levels late in the day was found. On average, the entire sample had moderate symptoms and symptom distress for urinary, bowel, and sexual dysfunction. The RP group reported significantly more urinary and sexual dysfunction symptoms and fewer bowel symptoms than did the RT group. Perceived stress was positively correlated with higher afternoon cortisol levels and greater symptom distress. Conclusion: Moderate symptoms and symptom distress found in our sample indicate the need for interventions to address these outcomes in men treated for prostate cancer. Self-reported perceived stress can be used to assess the stress level and symptom distress in clinic setting. Implications for Practice: Patients treated for prostate cancer with RP or RT should be assessed for symptoms and symptom distress and targeted for early symptom management interventions.

Biomarkers for Cognitive Aging Part I Telomere Length, Blood Pressure and Cognition Among Individuals with Hypertension

Chronological age is used as a marker for age-associated changes in cognitive function. However, there is great interindividual variability in cognitive ability among people of the same age. Physiological age rather than chronological age should be more closely associated with age-related cognitive changes because these changes are not universal and are likely dependent on several factors in addition to the number of years lived. Cognitive function is associated with successful self-management, and a biological marker that reflects physiological age and is associated with cognitive function could be used to identify risk for failure to self-manage. The purpose of this study was to investigate the association between telomere length, a known biomarker of age; blood pressure; cognitive assessments; and adherence to antihypertensive medication among community-dwelling middle-aged and older adults. The authors administered a battery of cognitive assessments to 42 participants (M = 69 years of age), collected blood samples, and isolated peripheral blood mononuclear leukocytes for genomic DNA. The authors determined relative telomere length using Cawthon’s method for real-time quantitative polymerase chain reaction (RT-qPCR) and measured medication adherence using an electronic medication monitoring system (MEMS by Aardex) over 8 weeks. Findings indicate that telomere length was inversely associated with systolic blood pressure (r = −.38, p < .01) and diastolic blood pressure (r = −.42, p < .01) but not with cognitive assessments or adherence. The authors discuss the nonsignificant findings between telomere length and cognitive assessments including the potential modifying role of gender.

Gene therapy with vascular endothelial growth factor reduces angina.

A placebo-controlled, double-blind, randomized study found that subjects randomized to the vascular endothelial growth factor (VEGF) gene-receiving treatment group showed a greater level of angina reduction in comparison to control subjects who received saline as a placebo. These data provide hope for a new treatment option for those who are not candidates for invasive therapeutic procedures and are refractory to medical therapy for angina. Furthermore, the findings are important to the areas of therapeutic angiogenesis and gene therapy as a whole. This article discusses VEGF and its brief history as a form of gene therapy in the context of the VEGF gene therapy trial that the American Heart Association has recognized as one of the top 10 scientific advances of 2001.

Disruption of filamentous actin diminishes hormonally evoked Ca2+ responses in rat liver

Previous studies have suggested a role for the actin cytoskeleton in hormonally evoked Ca2+ signaling in the liver. Here, we present evidence supporting a connection between filamentous actin (F-actin) organization and the ability of vasopressin and glucagon to increase cytosolic free-Ca2+ ([Ca2+]i) levels. F-actin was disrupted in hepatic cells by perfusion of rat liver with cytochalasin D. Epifluorescence microscopy of subsequently isolated cells showed reduced cortical fluorescent phalloidin staining in cytochalasin D-treated liver cells. Cytochalasin D pretreatment of liver cells reduced the vasopressin-stimulated elevation of [Ca2+]i by 60% and of glucagon by 50%. Experiments performed on cytochalasin D-treated cells using Mn2+ as an indicator of Ca2+ influx quenched fura-2 fluorescence signals following vasopressin administration. This indicates that a structurally intact cortical F-actin web is not a prerequisite for the influx of calcium. Therefore, the attenuation of the increase in cytosolic calcium observed in cytochalasin D-treated liver cells was likely caused either by the depletion of the calcium store by treatment with cytochalasin D or by the need for an intact cytoskeletal structure for its release. Because the resting level of calcium did not change in cells exposed to cytochalasin D, the latter is likely. The reduced [Ca2+]i response may be the mechanism by which cytochalasin D pretreatment inhibits vasopressin-induced metabolic effects. Cytochalasin D pretreatment also decreased the ability of glucagon to stimulate gluconeogenesis and reduced the stimulation of O2 uptake usually observed following glucagon administration. In conclusion, these results suggest that the hormonal elevation of [Ca2+]i and resultant activation of specific metabolic pathways require normal F-actin organization.