Víctor Manuel Mendoza-Núñez

Menopause as risk factor for oxidative stress.

ObjectiveThe aim of this study was to determine the influence of menopause (hypoestrogenism) as a risk factor for oxidative stress. MethodsWe carried out a cross-sectional study with 187 perimenopausal women from Mexico City, including 94 premenopausal (mean ± SD age, 44.9 ± 4.0 y; estrogen, 95.8 ± 65.7 pg/mL; follicle-stimulating hormone, 13.6 ± 16.9 mIU/mL) and 93 postmenopausal (mean ± SD age, 52.5 ± 3.3 y; estrogen, 12.8 ± 6.8 pg/mL; follicle-stimulating hormone, 51.4 ± 26.9 mIU/mL) women. We measured lipoperoxides using a thiobarbituric acid–reacting substance assay, erythrocyte superoxide dismutase and glutathione peroxidase activities, and the total antioxidant status with the Randox kit. An alternative cutoff value for lipoperoxide level of 0.320 &mgr;mol/L or higher was defined on the basis of the 90th percentile of young healthy participants. All women answered the Menopause Rating Scale, the Athens Insomnia Scale, and a structured questionnaire about pro-oxidant factors, that is, smoking, consumption of caffeinated and alcoholic beverages, and physical activity. Finally, we measured weight and height and calculated body mass index. ResultsThe lipoperoxide levels were significantly higher in the postmenopausal group than in the premenopausal group (0.357 ± 0.05 vs 0.331 ± 0.05 &mgr;mol/L, P = 0.001). Using logistic regression to control pro-oxidant variables, we found that menopause was the main risk factor for oxidative stress (odds ratio, 2.62; 95% CI, 1.35-5.11; P < 0.01). We also found a positive correlation between menopause rating score, insomnia score, and lipoperoxides, and this relationship was most evident in the postmenopausal group (menopause scale, r = 0.327 [P = 0.001]; insomnia scale, r = 0.209 [P < 0.05]). ConclusionsOur findings suggest that the depletion of estrogen in postmenopause could cause oxidative stress in addition to the known symptoms.

Mesenchymal Stem Cells Derived from Dental Pulp: A Review

The mesenchymal stem cells of dental pulp (DPSCs) were isolated and characterized for the first time more than a decade ago as highly clonogenic cells that were able to generate densely calcified colonies. Now, DPSCs are considered to have potential as stem cell source for orthopedic and oral maxillofacial reconstruction, and it has been suggested that they may have applications beyond the scope of the stomatognathic system. To date, most studies have shown that, regardless of their origin in third molars, incisors, or exfoliated deciduous teeth, DPSCs can generate mineralized tissue, an extracellular matrix and structures type dentin, periodontal ligament, and dental pulp, as well as other structures. Different groups worldwide have designed and evaluated new efficient protocols for the isolation, expansion, and maintenance of clinically safe human DPSCs in sufficient numbers for various therapeutics protocols and have discussed the most appropriate route of administration, the possible contraindications to their clinical use, and the parameters to be considered for monitoring their clinical efficacy and proper biological source. At present, DPSC-based therapy is promising but because most of the available evidence was obtained using nonhuman xenotransplants, it is not a mature technology.

Implementation of an active aging model in Mexico for prevention and control of chronic diseases in the elderly

BackgroundWorld Health Organization cites among the main challenges of populational aging the dual disease burden: the greater risk of disability, and the need for care. In this sense, the most frequent chronic diseases during old age worldwide are high blood pressure, type 2 diabetes mellitus, cancer, arthritis, osteoporosis, depression, and dementia. Chronic disease-associated dependency represents an onerous sanitary and financial burden for the older adult, the family, and the health care system. Thus, it is necessary to propose community-level models for chronic disease prevention and control in old age. The aim of the present work is to show our experience in the development and implementation of a model for chronic disease prevention and control in old age at the community level under the active aging paradigm.Methods/DesignA longitudinal study will be carried out in a sample of 400 elderly urban and rural-dwelling individuals residing in Hidalgo State, Mexico during five years. All participants will be enrolled in the model active aging. This establishes the formation of 40 gerontological promoters (GPs) from among the older adults themselves. The GPs function as mutual-help group coordinators (gerontological nuclei) and establish self-care and self-promotion actions for elderly well-being and social development. It will be conformed a big-net of social network of 40 mutual-help groups of ten elderly adults each one, in which self-care is a daily practice for chronic disease prevention and control, as well as for achieving maximal well-being and life quality in old age. Indicators of the models impact will be (i) therapeutic adherence; (ii) the incidence of the main chronic diseases in old age; (iii) life expectancy without chronic diseases at 60 years of age; (iv) disability adjusted life years lost; (v) years of life lost due to premature mortality, and (vi) years lived with disability.DiscussionWe propose that the implementation of the model active aging framework will permits the empowerment of older adults, which constitutes basic social capital for chronic disease prevention and control in old age.

Serum Leptin Levels and Blood Pressure in the Overweight Elderly

BACKGROUND Leptin is a protein produced by adipocytes that reduces reflex appetite by blocking the Y neuropeptide, thus causing body weight loss. A large percentage of elderly people are reported to exhibit obesity, which may be caused by low leptin serum levels. However, hypertension is a highly prevalent condition in old age. Obesity under these circumstances is an added risk factor due to the presence and severity of hypertension and thus can be related with leptin serum levels. Our objective was to determine the relationship between leptin serum levels and hypertension in obese elderly persons. METHODS A comparative transverse study was done in a random sample of 61 elderly persons-36 obese and 25 non-obese. Their blood pressure and their leptin serum levels by RIA were measured. RESULTS Leptin serum levels showed a statistically significant difference (p <0.05) in elderly obese individuals (12.8 +/- 4.4 microg/L vs. 9.8 +/- 4.2 microg/L). Likewise, 45% of obese elderly individuals and 20% of the non-obese were hypertensive with a predominant elevation of the systolic pressure. CONCLUSIONS The higher serum leptin levels in obese elderly individuals suggests that aging is associated with resistance to leptin and/or to a decrease of receptors for this hormone. The high incidence of hypertension during the aging process is the result of associated obesity (OR = 3.2, CI 0.88-13.14).

Program of active aging in a rural Mexican community: a qualitative approach

BackgroundEducation is one of the key elements in the promotion of a thorough paradigm for active aging. The aim of this study is to analyze factors that contribute the empowerment of older adults in a rural Mexican community and, thus, promote active aging.MethodsThe study was conducted in a rural Mexican community (Valle del Mezquital), based on an action-research paradigm. One hundred and fifty-five elderly subjects with elementary school education participated in a formal training program promoting gerontological development and health education. Participants in turn became coordinators of mutual-help groups (gerontological nucleus) in Mexico. In-depth interviews were carried out to assess the empowerment after training for active aging.ResultsIt was found that there was an increasing feeling of empowerment, creativity and self-fulfillment among participants. Among the main factors that positively influenced training of the elderly toward active aging were the teaching of gerontology topics themselves; besides, their motivation, the self-esteem, the increased undertaking of responsibility, the feeling of belonging to the group, and the sharing of information based on personal experience and on gerontological knowledge.ConclusionThe main factors that contribute to empowerment of older adults in a rural Mexican community for participate in active aging programs are the training and teaching of gerontology topics themselves; besides, their interest, experience and involvement.

High Dosage of Ascorbic Acid and Alpha-Tocopherol Is Not Useful for Diminishing Oxidative Stress and DNA Damage in Healthy Elderly Adults

Aim: To determine the useful dosage of ascorbic acid and alpha-tocopherol against oxidative stress and DNA damage in the elderly. Methods: A double-blind controlled clinical assay carried out in a sample of 66 healthy subjects divided into three age-paired random groups with 22 subjects in each group. Group A received placebo and group B was administered 500 mg of ascorbic acid and 400 IU of alpha-tocopherol, whereas group C received 1,000 mg of ascorbic acid and 400 IU of alpha-tocopherol for a 6-month period. The following measurements were performed before and after the 6-month treatment period: thiobarbituric acid reactive substances (TBARS); total antioxidant status (TAS); superoxide dismutase (SOD), and glutation peroxidase (GPx) and DNA damage by comet assay. Results: After 6 months, group B subjects exhibited an increase in SOD and GPx enzyme levels; however, this was not statistically significant (p > 0.05). Likewise, TBARS and TAS concentrations remained unchanged (p > 0.05). In addition, in group C the decrease in TBARS and increase in SOD, GPx, and TAS were not statistically significant (p > 0.05). Similarly, average DNA migration showed no significant differences with high-dosage ascorbic acid and alpha-tocopherol. Conclusion: These findings suggest that administration of 1,000 mg of ascorbic acid plus 400 IU of alpha-tocopherol for 6 months is not useful for diminishing oxidative stress and DNA damage in healthy elderly adults.

Effects of University Programs for Older Adults: Changes in Cultural and Group Stereotype, Self-Perception of Aging, and Emotional Balance

University Programs for Older Adults (Programas Universitarios para Adultos Mayores or PUMAs) have been developed throughout the world as an outcome of two worldwide policies: Life Long Learning (LLL) and Active Aging as a priority direction (UN, 2002). According to these policies, older persons should become full participants in the development process of a society, sharing in its benefits, while policies and actions should promote a positive view of aging. The present paper sets out to report some of the results from the evaluation of four PUMAs offered in 2009–2010 at four Universities: Autónoma University of Madrid (Spain), Autónoma University of Mexico (Mexico), Catholic University (Chile), and La Habana University (Cuba). With this purpose, a study with quasiexperimental design and nonequivalent control group was carried out. In total, 313 students (75% women, age range 50–87) on these four PUMAs and 190 controls (77% female, age range 50–91) participated in this evaluation study. Pre- and postexperimental and control comparisons results yielded significant differences in the expected direction: those people attending PUMAs significantly improved their self-perception of aging and group stereotypes, as well as significantly reduced their negative affect, and improving their emotional balance. At the same time, their perception of cultural age stereotypes became more negative. The results are discussed from the point of view of the II International Plan of Action on Aging objectives: the reduction of negative stereotypes and the promotion of the role of PUMAs in active aging.

Relationship between Metabolic Syndrome Components and Oxidative Stress in Elderly Community-Dwelling Mexicans

Aim: To determine the relationship between metabolic syndrome (MetS) components and oxidative stress (OxS) in elderly community-dwelling Mexicans. Methods: We carried out a comparative cross-sectional study on 113 elderly subjects (≧60 years old); 50 of them did not have MetS and 63 did have MetS (based on Adult Treatment Panel III criteria). We measured total antioxidant status (TAS), plasma lipid peroxidation (LPO), antioxidant activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx), and calculated the SOD/GPx ratio. High blood pressure (HBP) was defined as systolic blood pressure (SBP) ≧140 mm Hg and/or diastolic blood pressure (DBP) ≧90 mm Hg. Results: We found a statistically significant increase in the percentage of cases of severe OxS in elderly subjects with MetS in comparison to healthy elderly (17 vs. 8%, OR: 7.33, 95% CI: 1.38–42.39; p < 0.01). It was observed that subjects with 5 MetS components had a 10-fold higher risk of developing OxS than subjects with 1 component (OR: 11.00, 95% CI: 1.72–115.17; p < 0.01). A positive correlation between SBP and LPO (r = 0.202, p < 0.05), and a negative correlation of SBP and DBP with TAS activity (r = –0.232, p < 0.05; r = –0.211, p < 0.05) were also observed. Conclusion: Our findings suggest that MetS is linked to severe OxS, that the number of metabolic syndrome components is a significant risk factor in the development of OxS, and that HBP is the most important metabolic syndrome component linked to OxS in the elderly.

Aging Linked to Type 2 Diabetes Increases Oxidative Stress and Chronic Inflammation

Oxidative stress (OxS) and inflammation are physiopathological mechanisms related to diabetes and aging. We evaluated the additive effect of diabetes and aging on OxS and inflammation in a cross-sectional comparative study of 228 subjects: (1) 56 healthy adults (mean age, 47 ± 7 years); (2) 60 diabetic adults (mean age, 52 ± 6 years); (3) 40 healthy elderly adults (mean age, 67 ± 7 years); and (4) 72 diabetic elderly adults (mean age, 68 ± 7 years). We measured levels of glycosylated hemoglobin (HbA1c), plasma lipid peroxides, superoxide dismutase, glutathione peroxidase, total antioxidants, and tumor necrosis factor-alpha (TNF-α). The results indicate that diabetes is a risk factor for subjects with high serum levels of TNF-α (odds ratio [OR] = 12.1; 95% confidence interval [95% CI], 5.0-28; p < 0.001); this correlation becomes stronger when it is also associated with aging (OR = 14; 95% CI, 3.7-53.7; p < 0.05). Likewise, we observed that diabetes is an independent risk factor for OxS (OR = 2.1; 95% CI, 1.2-3.8; p < 0.05), and a stronger factor in older patients (OR = 3.1; 95% CI, 1.3-7.5; p < 0.05). Our findings suggest that aging, in concert with diabetes, exerts an additive effect on OxS and inflammation.

Effect of Tai Chi versus Walking on Oxidative Stress in Mexican Older Adults

It has recently been reported that the practice of Tai Chi reduces oxidative stress (OxS), but it is not clear whether walking or Tai Chi produces a greater antioxidant effect. The aim of the present study was to evaluate the effect of the practice of Tai Chi and walking on markers for OxS. We carried out a quasi-experimental study with 106 older adults between 60 and 74 years of age who were clinically healthy and divided into the following groups: (i) control group (n = 23), (ii) walking group (n = 43), and (iii) Tai Chi group (n = 31). We measured the levels of lipoperoxides (LPO), antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx), and total antioxidant status (TAS) pre- and post-intervention in all subjects. The data were subjected to a covariant analysis. We found lower levels of LPO in the Tai Chi group compared with the walking group (Tai Chi, 0.261 ± 0.02; walking, 0.331 ± 0.02; control, 0.304 ± 0.023 µmol/L; P = 0.05). Likewise, we observed significantly higher SOD activity and lower OxS-score in the Tai Chi group (P < 0.05). Our findings suggest that the practice of Tai Chi produces a more effective antioxidant effect than walking.