The Effects of Caregiving on Women's Self-Assessed Health Status: An International Comparison

To compare the self-assessed health status (SAHS) of female caregivers of older adults across the United States (N = 1,496), China (N = 485), and the United Kingdom (N = 252), data from three data sets were analyzed to isolate significant predictors of SAHS using an adapted meta-analytic technique. Higher income and full-time employment were predictors of higher SAHS; chronic health condition and emotional strain predicted lower SAHS. Female gender was a predictor of lower SAHS. The health status of women was negatively impacted by the caregiving experience. National policies, such as those in the United Kingdom, may result in higher SAHS for women caregivers.     

Pyruvate kinase and aspartate-glutamate carrier distributions reveal key metabolic links between neurons and glia in retina

Symbiotic relationships between neurons and glia must adapt to structures, functions, and metabolic roles of the tissues they are in. We show here that Müller glia in retinas have specific enzyme deficiencies that can enhance their ability to synthesize Gln. The metabolic cost of these deficiencies is that they impair the Müller cell’s ability to metabolize Glc. We show here that the cells can compensate for this deficiency by using metabolites produced by neurons. Müller glia are deficient for pyruvate kinase (PK) and for aspartate/glutamate carrier 1 (AGC1), a key component of the malate-aspartate shuttle. In contrast, photoreceptor neurons express AGC1 and the M2 isoform of pyruvate kinase, which is commonly associated with aerobic glycolysis in tumors, proliferating cells, and some other cell types. Our findings reveal a previously unidentified type of metabolic relationship between neurons and glia. Müller glia compensate for their unique metabolic adaptations by using lactate and aspartate from neurons as surrogates for their missing PK and AGC1.Aerobic glycolysis is a metabolic adaptation that proliferating cells use to meet anabolic demands (1, 2). In tumors, it is called the “Warburg effect.” Tumors convert ∼90% of Glc they consume to lactate (Lac). The brain converts only 2–25% of the Glc it uses to Lac (3).In retinas of vertebrate animals, energy is produced in a way that resembles tumor metabolism more than brain metabolism. Aerobic glycolysis accounts for 80–96% of Glc used by retinas (4–7). Retinas are made up of neurons and glia (8). The outermost layer is occupied by photoreceptors (PRs). The inner layers are a diverse collection of signal processing neurons. Müller glia spans the thickness of the retina. The site of aerobic glycolysis in retina has not been established.Exchange of fuels is an important part of the relationship between neurons and glia (9–12). Transfer of metabolites between intracellular compartments also is important. Glycolysis is supported by reoxidation of cytosolic NADH, which can be catalyzed by lactate dehydrogenase (LDH) or by the malate-aspartate shuttle (MAS). PRs and other neurons in retinas express aspartate/glutamate carrier 1 (AGC1; also known as “Aralar”) (13), a mitochondrial aspartate/glutamate carrier that has a key role in the MAS. However, Müller cells (MCs) are AGC1-deficient (13). The significance of the distribution of AGC1 has been enigmatic.Aerobic metabolism in tumors is linked to expression of the M2 isoform of pyruvate kinase, PKM2 (14, 15). Pyruvate kinase (PK) catalyzes the final step in glycolysis, synthesis of Pyr (16). Liver (PKL) and erythrocyte (PKR) isoforms are splice variants of the PKLR gene, and PKM1 and PKM2 are splice variants of the PKM gene. A unique feature of PKM2 is that it is responsive to allosteric and posttranslational regulators (16). PKM2 expression in cancer cells correlates with reduced yield of ATP from Glc and accumulation of glycolytic intermediates. PKM2 also favors synthesis of Ser and pentose phosphate pathway intermediates that support anabolic activity (17).Association of PKM2 with aerobic glycolysis in tumors motivated us to explore the relationship between PKM2 and aerobic glycolysis in retina. We found that PKM2 is abundant and only in the outer retina, implicating PRs as a primary site of aerobic glycolysis. Unexpectedly, we also found MCs are deficient for all isoforms of PK.The deficiency of MCs for AGC1 and PK led us to investigate metabolic relationships between PRs and MCs. We found cultured MCs have an impaired ability to metabolize Glc, but they metabolize Asp effectively. Our findings reveal that metabolic benefits of down-regulating PK and AGC1 in MCs have led to specific metabolic adaptations in the retina. Rather than use Glc to fuel their mitochondria, MCs use Lac and Asp from neurons as surrogates for their missing PK and AGC1 activities.     

Long-term safety and effectiveness of drug-eluting stents compared to bare metal stents in ST elevation myocardial infarction: findings from the Guthrie Health Off-label Stent (GHOST) Registry

Background: Multiple randomized trials and observational studies have shown drug‐eluting stents (DES) to be safe and effective at 3‐year follow‐up in stent thrombosis (ST)‐segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI). However, outcomes data beyond 3–4 years after DES implantation are sparse. Methods: We studied 554 STEMI patients who underwent successful PCI with either DES or bare metal stent (BMS). Primary study end‐points were time to occurrence of ST and the composite of death or myocardial infarction (MI). Secondary end‐points were time to occurrence of major adverse cardiac events (MACEs) and discrete events that comprise MACE (death, MI, and target vessel revascularization [TVR]). Outcomes of the DES and BMS groups were assessed by survival analysis and multivariable Cox regression. Results: There were 205 (37%) patients who received DES and 349 (63%) patients who received BMS. At a median follow‐up of 41.4 months after PCI, there were no differences in the unadjusted incidence of ST (ST, 3.4 vs. 4.3%, log‐rank P = 0.61) and MI (6.8% vs. 8%, P = 0.61) between DES versus BMS groups, respectively. However, DES implantation was associated with lower unadjusted incidence of death or MI (11% vs. 23.5%, P = 0.0002), MACE (16% vs. 34%, P < 0.0001), death (6.3% vs. 17%, P = 0.0004), and TVR (9.8% vs. 18%, P = 0.008) than BMS implantation. In multivariable analyses, DES implantation was associated with significantly lower incidence of MACE (adjusted HR = 0.47 [95% CI: 0.31–0.76], P = 0.0007) than BMS implantation. Conclusion: In our study of STEMI patients, DES implantation was safer than BMS implantation and was associated with lower MACE at long‐term follow‐up. (J Interven Cardiol 2012;25:118–125)     

Lifestyle determinants of C-reactive protein in middle-aged, urban Chinese men

Background and Aim: Increased levels of C-reactive protein (CRP), common in aging populations, are associated with higher risk for chronic diseases, including diabetes and coronary heart disease. The aim of this study was to investigate associations between lifestyle factors and high CRP among middle-aged men living in Shanghai, China.Methods and Results: In this cross-sectional study, 3978 urban Chinese men aged 40–74 years who were free of type-2 diabetes at baseline provided fasting blood samples, anthropometric measurements and information on lifestyle factors and disease history.Dietary patterns were assessed by factor analysis. Participants were categorised into two groups according to CRP level: normal (≤3 mg/L) and high (>3 mg/L). Associations between CRP categories and lifestyle factors were investigated by using logistic regression.Obesity, weight gain, cigarette smoking and alcohol intake were positively associated with high CRP levels, while physical activity and a dietary pattern with high consumption of fruit were inversely related to high CRP levels. A positive trend of marginal significance between quintiles of a dietary pattern with high consumption of meat and high CRP levels was also observed. No association between tea intake and CRP level was observed.Conclusions: Components of an adverse lifestyle were associated with high CRP levels. Obesity, smoking and alcohol intake were associated with high CRP, a biomarker of low-grade inflammation in middle-aged men, while a dietary pattern rich in fruit and high physical activity were inversely associated with the prevalence of high CRP.