N-Terminomic Identification of Intracellular MMP-2 Substrates in Cardiac Tissue.

Proteases are enzymes that induce irreversible post-translational modifications by hydrolyzing amide bonds in proteins. One of these proteases is matrix metalloproteinase-2 (MMP-2), which has been shown to modulate extracellular matrix remodeling and intracellular proteolysis during myocardial injury. However, the substrates of MMP-2 in heart tissue are limited, and lesser known are the cleavage sites. Here, we used degradomics to investigate the substrates of intracellular MMP-2 in rat ventricular extracts. First, we designed a novel, constitutively active MMP-2 fusion protein (MMP-2-Fc) that we expressed and purified from mammalian cells. Using this protease, we proteolyzed ventricular extracts and used subtiligase-mediated N-terminomic labeling which identified 95 putative MMP-2-Fc proteolytic cleavage sites using mass spectrometry. The intracellular MMP-2 cleavage sites identified in heart tissue extracts were enriched for proteins primarily involved in metabolism, as well as the breakdown of fatty acids and amino acids. We further characterized the cleavage of three of these MMP-2-Fc substrates based on the gene ontology analysis. We first characterized the cleavage of sarco/endoplasmic reticulum calcium ATPase (SERCA2a), a known MMP-2 substrate in myocardial injury. We then characterized the cleavage of malate dehydrogenase (MDHM) and phosphoglycerate kinase 1 (PGK1), representing new cardiac tissue substrates. Our findings provide insights into the intracellular substrates of MMP-2 in cardiac cells, suggesting that MMP-2 activation plays a role in cardiac metabolism.

Data-Independent Acquisition Proteomics and N-Terminomics Methods Reveal Alterations in Mitochondrial Function and Metabolism in Ischemic-Reperfused Hearts.

Myocardial ischemia-reperfusion (IR) (stunning) injury triggers changes in the proteome and degradome of the heart. Here, we utilize quantitative proteomics and comprehensive degradomics to investigate the molecular mechanisms of IR injury in isolated rat hearts. The control group underwent aerobic perfusion, while the IR injury group underwent 20 min of ischemia and 30 min of reperfusion to induce a stunning injury. As MMP-2 activation has been shown to contribute to myocardial injury, hearts also underwent IR injury with ARP-100, an MMP-2-preferring inhibitor, to dissect the contribution of MMP-2 to IR injury. Using data-independent acquisition (DIA) and mass spectroscopy, we quantified 4468 proteins in ventricular extracts, whereby 447 proteins showed significant alterations among the three groups. We then used subtiligase-mediated N-terminomic labeling to identify more than a hundred specific cleavage sites. Among these protease substrates, 15 were identified following IR injury. We identified alterations in numerous proteins involved in mitochondrial function and metabolism following IR injury. Our findings provide valuable insights into the biochemical mechanisms of myocardial IR injury, suggesting alterations in reactive oxygen/nitrogen species handling and generation, fatty acid metabolism, mitochondrial function and metabolism, and cardiomyocyte contraction.

The roles of intracellular proteolysis in cardiac ischemia-reperfusion injury.

Ischemic heart disease remains a leading cause of human mortality worldwide. One form of ischemic heart disease is ischemia-reperfusion injury caused by the reintroduction of blood supply to ischemic cardiac muscle. The short and long-term damage that occurs due to ischemia-reperfusion injury is partly due to the proteolysis of diverse protein substrates inside and outside of cardiomyocytes. Ischemia-reperfusion activates several diverse intracellular proteases, including, but not limited to, matrix metalloproteinases, calpains, cathepsins, and caspases. This review will focus on the biological roles, intracellular localization, proteolytic targets, and inhibitors of these proteases in cardiomyocytes following ischemia-reperfusion injury. Recognition of the intracellular function of each of these proteases includes defining their activation, proteolytic targets, and their inhibitors during myocardial ischemia-reperfusion injury. This review is a step toward a better understanding of protease activation and involvement in ischemic heart disease and developing new therapeutic strategies for its treatment.

Matrix metalloproteinase-2 proteolyzes mitofusin-2 and impairs mitochondrial function during myocardial ischemia-reperfusion injury.

During myocardial ischemia and reperfusion (IR) injury matrix metalloproteinase-2 (MMP-2) is rapidly activated in response to oxidative stress. MMP-2 is a multifunctional protease that cleaves both extracellular and intracellular proteins. Oxidative stress also impairs mitochondrial function which is regulated by different proteins, including mitofusin-2 (Mfn-2), which is lost in IR injury. Oxidative stress and mitochondrial dysfunction trigger the NLRP3 inflammasome and the innate immune response which invokes the de novo expression of an N-terminal truncated isoform of MMP-2 (NTT-MMP-2) at or near mitochondria. We hypothesized that MMP-2 proteolyzes Mfn-2 during myocardial IR injury, impairing mitochondrial function and enhancing the inflammasome response. Isolated hearts from mice subjected to IR injury (30 min ischemia/40 min reperfusion) showed a significant reduction in left ventricular developed pressure (LVDP) compared to aerobically perfused hearts. IR injury increased MMP-2 activity as observed by gelatin zymography and increased degradation of troponin I, an intracellular MMP-2 target. MMP-2 preferring inhibitors, ARP-100 or ONO-4817, improved post-ischemic recovery of LVDP compared to vehicle perfused IR hearts. In muscle fibers isolated from IR hearts the rates of mitochondrial oxygen consumption and ATP production were impaired compared to those from aerobic hearts, whereas ARP-100 or ONO-4817 attenuated these reductions. IR hearts showed higher levels of NLRP3, cleaved caspase-1 and interleukin-1ß in the cytosolic fraction, while the mitochondria-enriched fraction showed reduced levels of Mfn-2, compared to aerobic hearts. ARP-100 or ONO-4817 attenuated these changes. Co-immunoprecipitation showed that MMP-2 is associated with Mfn-2 in aerobic and IR hearts. ARP-100 or ONO-4817 also reduced infarct size and cell death in hearts subjected to 45 min ischemia/120 min reperfusion. Following myocardial IR injury, impaired contractile function and mitochondrial respiration and elevated inflammasome response could be attributed, at least in part, to MMP-2 activation, which targets and cleaves mitochondrial Mfn-2. Inhibition of MMP-2 activity protects against cardiac contractile dysfunction in IR injury in part by preserving Mfn-2 and suppressing inflammation.

Activity patterns related to depression symptoms in stressed dementia caregivers.

OBJECTIVES: Self-reported activity restriction is an established correlate of depression in dementia caregivers (dCGs). It is plausible that the daily distribution of objectively measured activity is also altered in dCGs with depression symptoms; if so, such activity characteristics could provide a passively measurable marker of depression or specific times to target preventive interventions. We therefore investigated how levels of activity throughout the day differed in dCGs with and without depression symptoms, then tested whether any such differences predicted changes in symptoms 6 months later. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: We examined 56 dCGs (mean age = 71, standard deviation (SD) = 6.7; 68% female) and used clustering to identify subgroups which had distinct depression symptom levels, leveraging baseline Center for Epidemiologic Studies of Depression Scale-Revised Edition and Patient Health Questionnaire-9 (PHQ-9) measures, as well as a PHQ-9 score from 6 months later. Using wrist activity (mean recording length = 12.9 days, minimum = 6 days), we calculated average hourly activity levels and then assessed when activity levels relate to depression symptoms and changes in symptoms 6 months later. RESULTS: Clustering identified subgroups characterized by: (1) no/minimal symptoms (36%) and (2) depression symptoms (64%). After multiple comparison correction, the group of dCGs with depression symptoms was less active from 8 to 10 AM (Cohen's d ≤ -0.9). These morning activity levels predicted the degree of symptom change on the PHQ-9 6 months later (per SD unit ß = -0.8, 95% confidence interval: -1.6, -0.1, p = 0.03) independent of self-reported activity restriction and other key factors. CONCLUSIONS: These novel findings suggest that morning activity may protect dCGs from depression symptoms. Future studies should test whether helping dCGs get active in the morning influences the other features of depression in this population (i.e. insomnia, intrusive thoughts, and perceived activity restriction).

Novel methods for assessment of vulnerability to financial exploitation (FE).

Financial exploitation (FE) is a complex problem influenced by many factors. This article introduces two novel methods for assessment of FE vulnerability: (1) performance-based measures of financial skills using web-based simulations of common financial tasks; (2) scam vulnerability measures based on credibility ratings of common scam scenarios. Older adults who were male, younger, Hispanic, more educated, with higher incomes performed better on the simulated financial tasks. Better performance was also related to higher cognitive function and numeracy, and more experience with technology. On the scenario-based measures, older adults who were male, younger, African American, less educated, and lower income showed higher FE vulnerability. Higher scam vulnerability was also related to poorer performance on the simulated financial tasks, lower cognitive function, less experience with technology, more financial conflict/anxiety, more impulsivity, and more stranger-initiated FE. Findings indicate that these novel measures show promise as valid indicators of vulnerability to FE.

Staurosporine-induced cleavage of apoptosis-inducing factor in human fibrosarcoma cells is independent of matrix metalloproteinase-2.

Apoptosis-inducing factor (AIF) is a mitochondrial flavoprotein which mediates staurosporine (STS) - induced cell death. AIF cleavage and translocation to the cytosol is thought to be calpain-1-dependent as calpain inhibitors reduce AIF proteolysis; however, many calpain inhibitors also inhibit matrix metalloproteinase-2 (MMP-2) activity, an intracellular and extracellular protease implicated in apoptosis. Here we investigated whether MMP-2 activity is affected in response to STS and if it contributes to AIF cleavage. Human fibrosarcoma HT1080 cells were treated with STS (0.1 µM, 0.25-24 h). A significant increase in cellular MMP-2 activity was seen by gelatin zymography after a 6 h STS treatment, prior to induction of cell necrosis. Western blot showed the time-dependent appearance of two forms of AIF (∼60 and 45 kDa) in the cytosol which were significantly increased at 6 h. Surprisingly, knocking down MMP-2 or inhibiting its activity with MMP-2 preferring inhibitors ARP-100 or ONO-4817, or inhibiting calpain activity with ALLM or PD150606, did not prevent the STS-induced increase in cytosolic AIF. These results show that although STS rapidly increases MMP-2 activity, the cytosolic release of AIF may be independent of the proteolytic activities of MMP-2 or calpain.

Family Caregiving for Individuals With Heart Failure: A Scientific Statement From the American Heart Association.

Many individuals living with heart failure (HF) rely on unpaid support from their partners, family members, friends, or neighbors as caregivers to help manage their chronic disease. Given the advancements in treatments and devices for patients with HF, caregiving responsibilities have expanded in recent decades to include more intensive care for increasingly precarious patients with HF-tasks that would previously have been undertaken by healthcare professionals in clinical settings. The specific tasks of caregivers of patients with HF vary widely based on the patient's symptoms and comorbidities, the relationship between patient and caregiver, and the complexity of the treatment regimen. Effects of caregiving on the caregiver and patient range from physical and psychological to financial. Therefore, it is critically important to understand the needs of caregivers to support the increasingly complex medical care they provide to patients living with HF. This scientific statement synthesizes the evidence pertaining to caregiving of adult individuals with HF in order to (1) characterize the HF caregiving role and how it changes with illness trajectory; (2) describe the financial, health, and well-being implications of caregiving in HF; (3) evaluate HF caregiving interventions to support caregiver and patient outcomes; (4) summarize existing policies and resources that support HF caregivers; and (5) identify knowledge gaps and future directions for providers, investigators, health systems, and policymakers.

Caregiving Factors as Predictors of Care Recipient Mortality.

OBJECTIVE: Assess a conceptual model linking caregiving factors to care recipient mortality in a large representative sample of older adults with disability. DESIGN: Descriptive longitudinal study with 5-year mortality follow-up among older adults with disability. Baseline in person and telephone interviews/assessments of older adults with disability and their family caregivers carried out in 2011. SETTING: Representative samples of older US population and their family caregivers. PARTICIPANTS: US representative samples of older adults with disability aged 65 and over (National Health and Aging Study) and their family caregivers (National Study of Caregiving; www.nhats.org; N = 1,262). MEASUREMENT: Controlling for known risk factors for mortality in older adults, including age, gender, race, education, socioeconomic status, disability, and cognitive status, we assess the role of three caregiving factors (depression, anxiety, and burden) and three mediating factors (care recipient depression, anxiety, and unmet needs for care) as predictors of care recipient mortality. RESULTS: Caregiver burden, care recipient depression, and care recipient unmet needs are independent predictors of care recipient mortality. CONCLUSION: Caregiving factors may play an important role in the survival of their care recipients. This is a relatively unexplored research area that calls for fine-grained studies capturing caregiver-care recipient health-related interactions over time.

Family Caregiving for Older Adults.

Family members are the primary source of support for older adults with chronic illness and disability. Thousands of published empirical studies and dozens of reviews have documented the psychological and physical health effects of caregiving, identified caregivers at risk for adverse outcomes, and evaluated a wide range of intervention strategies to support caregivers. Caregiving as chronic stress exposure is the conceptual driver for much of this research. We review and synthesize the literature on the impact of caregiving and intervention strategies for supporting caregivers. The impact of caregiving is highly variable, driven largely by the intensity of care provided and the suffering of the care recipient. The intervention literature is littered with many failures and some successes. Successful interventions address both the pragmatics of care and the emotional toll of caregiving. We conclude with both research and policy recommendations that address a national agenda for caregiving.

Digital Monitoring of Sleep, Meals, and Physical Activity for Reducing Depression in Older Spousally-Bereaved Adults: A Pilot Randomized Controlled Trial.

OBJECTIVES: To evaluate the feasibility and acceptability of a behavioral intervention and explore its impact on depression symptom burden among older spousally-bereaved adults. METHODS: Participants were age ≥60 years, bereaved ≤8 months, and at high risk for depression. Participants were randomized to 12 weeks of digital monitoring of sleep, meals, and physical activity; digital monitoring plus health coaching; or enhanced usual care and followed for 9 months for new-episode depression. RESULTS: We enrolled 57 participants, 85% of eligible adults and 38% of all adults screened. We observed high levels of adherence in both digital monitoring (90%) and health coaching (92%); 88% of participants were retained. In linear mixed-effects models, depression symptoms significantly decreased, but the interaction between time and intervention was not significant. CONCLUSION: A behavioral intervention that uses both digital monitoring and motivational health coaching is feasible and acceptable to older bereaved adults.

Predictive Value of Matrix Metalloproteinases and Their Inhibitors for Mortality in Septic Patients: A Cohort Study.

PURPOSE: Over 170 biomarkers are being investigated regarding their prognostic and diagnostic accuracy in sepsis in order to find new tools to reduce morbidity and mortality. Matrix metalloproteinases (MMPs) and their inhibitors have been recently studied as promising new prognostic biomarkers in patients with sepsis. This study is aimed at determining the utility of several cutoff points of these biomarkers to predict mortality in patients with sepsis. MATERIALS AND METHODS: A multicenter, prospective, analytic cohort study was performed in the metropolitan area of Bucaramanga, Colombia. A total of 289 patients with sepsis and septic shock were included. MMP-9, MMP-2, tissue inhibitor of metalloproteinase 1 (TIMP-1), TIMP-2, TIMP-1/MMP-9 ratio, and TIMP-2/MMP-2 ratio were determined in blood samples. Value ranges were correlated with mortality to estimate sensitivity, specificity, positive predictive value, negative predictive value, and area under the receiving operating characteristic curve. RESULTS: Sensitivity ranged from 33.3% (MMP-9/TIMP-1 ratio) to 60.6% (TIMP-1) and specificity varied from 38.8% (MMP-2/TIMP-2 ratio) to 58.5% (TIMP-1). As for predictive values, positive predictive value range was from 17.5% (MMP-9/TIMP-1 ratio) to 70.4% (MMP-2/TIMP-2 ratio), whereas negative predictive values were between 23.2% (MMP-2/TIMP-2 ratio) and 80.9% (TIMP-1). Finally, area under the curve scores ranged from 0.31 (MMP-9/TIMP-1 ratio) to 0.623 (TIMP-1). CONCLUSION: Although TIMP-1 showed higher sensitivity, specificity, and negative predictive value, with a representative population sample, we conclude that none of the evaluated biomarkers had significant predictive value for mortality.

Agency and Motivation in Adulthood and Old Age.

This review addresses conceptual and empirical research about how individual agency and motivation influences development during adulthood and old age. The major life-span approaches to individual agency and developmental regulation are discussed, with a focus on the motivational theory of life-span development. Developmental agency unfolds through action cycles of pursuing long-term goals for optimal development. Individuals differ in their capacity to regulate their goal engagements effectively within the age-graded structure of opportunities and constraints in their life courses. We discuss a set of research examples about specific developmental challenges, such as transition to adulthood, biological aging, illness, and societal transformation, and show how individuals, as agents in their own development, navigate change for better or worse. We conclude with suggestions for future research.

Effects of continuous positive airway pressure therapy on daytime and nighttime arterial blood pressure in patients with severe obstructive sleep apnea and endothelial dysfunction.

PURPOSE: A nocturnal non-dipping or rise in blood pressure (BP) is associated with poor cardiovascular outcome. This study aimed to test whether continuous positive airway pressure (CPAP) therapy can reduce nocturnal BP and normalize the 24-h BP profile in patients with severe obstructive sleep apnea (OSA) and erectile dysfunction as a surrogate for endothelial dysfunction (ED). PATIENTS AND METHODS: Eighteen consecutive patients with OSA and ED on stable antihypertensive medication (age 55.8 ± 9.5 years, body mass index 35.5 ± 3.8 kg/m2, apnea-hypopnoea index 66.1 ± 27.4/h) were treated with CPAP for 6 months (average daily use 5.8 ± 2.3 h). Twenty-four hour BP recordings were performed using a portable monitoring device. Rising was defined as an increase, whereas non-dipping was defined as a fall in nocturnal BP of less than 10% compared to daytime values. Serum noradrenaline levels as markers of sympathetic activity were measured at baseline and at 6 month follow up. RESULTS: Compared to baseline, nocturnal systolic and diastolic BP were significantly reduced after CPAP therapy (128.5 ± 14 to 122.9 ± 11 mmHg, p = 0.036; 76.2 ± 9 to 70.5 ± 5 mmHg, p = 0.007). The frequency of non-dipping and rising nocturnal systolic BP, as well as mean nocturnal heart rate, was reduced after CPAP treatment (73 to 27%, p = 0.039; 20 to 7%, p = 0.625; from 81.5 ± 10 to 74.8 ± 8 beats per minute p = 0.043). Serum levels of noradrenaline were significantly lower after CPAP therapy (398 ± 195 ng/l vs. 303 ± 135 ng/l, p = 0.032). CONCLUSION: In patients with severe OSA and clinically apparent ED, CPAP therapy was associated with a decrease in nocturnal BP and serum noradrenaline levels, as well as a normalization of the 24-h BP profile.

Junctophilin-2 is a target of matrix metalloproteinase-2 in myocardial ischemia-reperfusion injury.

Junctophilin-2 is a structural membrane protein that tethers T-tubules to the sarcoplasmic reticulum to allow for coordinated calcium-induced calcium release in cardiomyocytes. Defective excitation-contraction coupling in myocardial ischemia-reperfusion (IR) injury is associated with junctophilin-2 proteolysis. However, it remains unclear whether preventing junctophilin-2 proteolysis improves the recovery of cardiac contractile dysfunction in IR injury. Matrix metalloproteinase-2 (MMP-2) is a zinc and calcium-dependent protease that is activated by oxidative stress in myocardial IR injury and cleaves both intracellular and extracellular substrates. To determine whether junctophilin-2 is targeted by MMP-2, isolated rat hearts were perfused in working mode aerobically or subjected to IR injury with the selective MMP inhibitor ARP-100. IR injury impaired the recovery of cardiac contractile function which was associated with increased degradation of junctophilin-2 and damaged cardiac dyads. In IR hearts, ARP-100 improved the recovery of cardiac contractile function, attenuated junctophilin-2 proteolysis, and prevented ultrastructural damage to the dyad. MMP-2 was co-localized with junctophilin-2 in aerobic and IR hearts by immunoprecipitation and immunohistochemistry. In situ zymography showed that MMP activity was localized to the Z-disc and sarcomere in aerobic hearts and accumulated at sites where the striated JPH-2 staining was disrupted in IR hearts. In vitro proteolysis assays determined that junctophilin-2 is susceptible to proteolysis by MMP-2 and in silico analysis predicted multiple MMP-2 cleavage sites between the membrane occupation and recognition nexus repeats and within the divergent region of junctophilin-2. Degradation of junctophilin-2 by MMP-2 is an early consequence of myocardial IR injury which may initiate a cascade of sequelae leading to impaired contractile function.

Feeling Relieved After the Death of a Family Member With Dementia: Associations With Postbereavement Adjustment.

OBJECTIVE: After an extended period of caregiving, the death of a family member with dementia can provide a sense of relief to individuals because caregiving has ended and their loved one is no longer suffering. Little is known about predeath factors associated with feeling relieved after the death of a family member with dementia. This study examined 1) predeath factors associated with caregiver (CG) relief; and 2) whether CG relief is associated with postbereavement adjustment, namely complicated grief and depression symptoms. METHODS: Participants were bereaved CGs aged 28-90 years old drawn from the Resources for Enhancing Alzheimer's Caregiver Health (REACH) (N = 223) and Family Caregiver Transition Support (FaCTS) (N = 89) studies. In each sample, demographics were assessed at baseline, and CG relief was assessed at the first follow-up assessment after death. Each study administered a similar bereavement battery to CGs following the death of their care recipients (CRs). RESULTS: CGs of late-stage dementia patients (FaCTS) reported more relief compared with CGs of early- to midstage dementia patients (REACH). CGs were more likely to experience relief if they were prepared for their CR's death and if they perceived their CR's death to be a relief to the CR. A multivariate regression model showed that greater CG relief was associated with less complicated grief postbereavement. CG relief was not significantly associated with depression symptoms. CONCLUSION: We show prospectively that the caregiving experience impacts feelings of relief, and that feeling relieved facilitates postbereavement adjustment by lessening symptoms of complicated grief.

Family Caregiving: A Vision for the Future.

The authors of this review both served on the National Academy of Science, Engineering, and Medicine Committee that produced the report, "Caring for an Aging America". In this commentary we summarize key findings and recommendations most relevant to clinicians and researchers in geriatric psychiatry and related disciplines. The report notes the growing prevalence of family caregiving in the United States, especially those caring for high-need patients with multiple chronic conditions, disability, and/or cognitive impairment. To support the capacity of family caregivers to perform critical caregiving tasks, the report recommends a major shift in healthcare policy toward collaborative partnerships among patients, their defined family, and providers of care. Optimizing the role of family caregivers will minimally require systematic attention to the identification, assessment, and support of family caregivers throughout the care delivery process. Research is needed to develop the tools and protocols to efficiently assess caregivers, and identify ways in which they can be integrated into existing clinical practices. We also need research to identify how to best implement, maintain, and evaluate caregiver support programs within clinical and community settings. The Centers for Medicare and Medicaid Services should be charged with developing, testing, and implementing provider payment reforms that motivate providers to engage and support family caregivers. Payment reforms should include clearly articulated performance standards that hold providers accountable for caregiver engagement, training, and support by explicitly including caregiver outcomes in quality measures.

Longitudinal Associations Between Cognitive Functioning and Depressive Symptoms Among Older Adult Spouses in the Cardiovascular Health Study.

OBJECTIVE: To examine the bidirectional associations between older adult spouses' cognitive functioning and depressive symptoms over time. DESIGN: Longitudinal, dyadic path analysis with the actor-partner interdependence model. SETTING: Data were from visit 5 (1992/1993), visit 8 (1995/1996), and visit 11 (1998/1999) of the Cardiovascular Health Study, a multisite, longitudinal, observational study of risk factors for cardiovascular disease in adults 65 years or older. Demographic information was from the 1989/1990 original and 1992/1993 African American cohort baseline visits. PARTICIPANTS: Husbands and wives from 1,028 community-dwelling married couples (N = 2,065). MEASUREMENTS: Cognitive functioning was measured with the Modified Mini-Mental State Exam. Depressive symptoms were measured using the 10-item Center for Epidemiologic Studies Depression Scale. Age, education, and disability (activities of daily living and instrumental activities of daily living) were included as covariates. RESULTS: Cross-partner associations (partner effects) revealed that one spouse's greater depressive symptoms predicted the other spouse's lower cognitive functioning, but a spouse's lower cognitive functioning did not predict the other spouse's greater depressive symptoms over time. Within-individual associations (actor effects) revealed that an individual's lower cognitive functioning predicted the individual's greater depressive symptoms over time, but greater depressive symptoms did not predict lower cognitive functioning over time. Effects did not differ for husbands and wives. CONCLUSION: Having a spouse who is depressed may increase one's risk of cognitive decline as well as one's risk of depression. Interventions for preventing cognitive decline and depression among older adults may be enhanced by considering the marital context.

Doxorubicin induces de novo expression of N-terminal-truncated matrix metalloproteinase-2 in cardiac myocytes.

Anthracyclines, such as doxorubicin, are commonly prescribed antineoplastic agents that cause irreversible cardiac injury. Doxorubicin cardiotoxicity is initiated by increased oxidative stress in cardiomyocytes. Oxidative stress enhances intracellular matrix metalloproteinase-2 (MMP-2) by direct activation of its full-length isoform and (or) de novo expression of an N-terminal-truncated isoform (NTT-MMP-2). As MMP-2 is localized to the sarcomere, we tested whether doxorubicin activates intracellular MMP-2 in neonatal rat ventricular myocytes (NRVM) and whether it thereby proteolyzes two of its identified sarcomeric targets, α-actinin and troponin I. Doxorubicin increased oxidative stress within 12 h as indicated by reduced aconitase activity. This was associated with a twofold increase in MMP-2 protein levels and threefold higher gelatinolytic activity. MMP inhibitors ARP-100 or ONO-4817 (1 µM) prevented doxorubicin-induced MMP-2 activation. Doxorubicin also increased the levels and activity of MMP-2 secreted into the conditioned media. Doxorubicin upregulated the mRNA expression of both full-length MMP-2 and NTT-MMP-2. α-Actinin levels remained unchanged, whereas doxorubicin downregulated troponin I in an MMP-independent manner. Doxorubicin induces oxidative stress and stimulates a robust increase in MMP-2 expression and activity in NRVM, including NTT-MMP-2. The sarcomeric proteins α-actinin and troponin I are, however, not targeted by MMP-2 under these conditions.

Acculturation level and caregiver outcomes from a randomized intervention trial to enhance caregivers' health: evidence from REACH II.

OBJECTIVE: Latinos comprise a growing segment of the caregiver population and vary widely in acculturation, yet little is known regarding how acculturation might affect caregiver stress or intervention outcomes. This study examined the relationship between acculturation and burden, bother, and depression in Latino dementia caregivers at baseline and following an intervention. METHODS: This was a secondary data analysis of 211 Latino caregivers of older adults with dementia from Resources for Enhancing Alzheimer's Caregiver Health (REACH) II, a multisite randomized trial of caregiver interventions. Baseline and follow-up data were used to run mixed-effects models examining the main and moderating effect of acculturation on caregiver stress. RESULTS: No significant main effect of acculturation was found for any of the outcome measures, controlling for demographic covariates. Acculturation moderated the effect of the intervention on caregiver burden: those who were more acculturated benefited more from the intervention. CONCLUSION: Differential acculturation for Latino caregivers was not directly associated with caregiver burden, bother, or depression, but was associated with reducing burden from the intervention. Future research should explore by what mechanism acculturation influences caregiver burden following an intervention.