Profile of urinary exosomal microRNAs and their contribution to Diabetic Kidney Disease through a predictive classification model

BACKGROUND

Diabetic kidney disease (DKD) is a main complication of Type 2 diabetes mellitus (T2DM). Exosomal microRNAs (exomiRs) participate in numerous early events in kidney injury regulating progression to DKD. This study aimed to evaluate the expression of exomiRs-126, 146 and 155 in urinary exosomes of patients with T2D and diabetic kidney disease to establish a predictive classification model with exomiRs and clinical variables in order to determine their contribution to DKD.

METHODS

The study group included 92 subjects: 64 patients diagnosed with T2DM subclassified into 2 groups with albuminuria (T2DM with albuminuria, n = 30) and without albuminuria (TD2M, n = 34) as well as 28 healthy, non-diabetic participants. Exosomes were isolated from urine and identified by TEM and flow cytometry. Profile expression of exomiRs-126, -146 and - 155 was evaluated by RT-qPCR. Data were analyzed by Permutational Multivariate Analysis of Variance (PERMANOVA), similarity percentage (SIMPER), principal coordinate analysis (PCO) and Canonical Analysis of Principal Coordinates (CAP).

RESULTS

T2DM patients with and without albuminuria showed higher levels of miR-155 and miR-146 compared to controls. In addition, T2DM patients with albuminuria presented a significant increase in miR-126 contrasted to controls and patients without albuminuria. PCO analysis explained 34.6% of the total variability of the data (PERMANOVA; P <0.0001). Subsequently, SIMPER analysis showed that miR-146, miR-155, and miR-126 together, with some clinical parameters, contributed to 50% of the between-group significance. Finally, the CAP analysis developed showed a correct classification of 89.01% with the analyzed parameters.

CONCLUSIONS

A platform using a combination of clinical variables and exomiRs could be used to to classify individuals with T2D as risk for developing DKD.

Identification of metabolic markers in patients with type 2 Diabetes by Ultrafast gas chromatography coupled to electronic nose. A pilot study

Metabolomics is a potential tool for the discovery of new biomarkers in the early diagnosis of diseases. An ultra-fast gas chromatography system equipped to an electronic nose detector (FGC eNose) was used to identify the metabolomic profile of Volatile Organic Compounds (VOCs) in type 2 diabetes (T2D) urine from Mexican population. A cross-sectional, comparative, and clinical study with translational approach was performed. We recruited twenty T2D patients and twenty-one healthy subjects. Urine samples were taken and analyzed by FGC eNose. Eighty-eight compounds were identified through Kovats's indexes. A natural variation of 30% between the metabolites, expressed by study groups, was observed in Principal Component 1 and 2 with a significant difference (p < 0.001). The model, performed through a Canonical Analysis of Principal coordinated (CAP), allowed a correct classification of 84.6% between healthy and T2D patients, with a 15.4% error. The metabolites 2-propenal, 2-propanol, butane- 2,3-dione and 2-methylpropanal, were increased in patients with T2D, and they were strongly correlated with discrimination between clinically healthy people and T2D patients. This study identified metabolites in urine through FGC eNose that can be used as biomarkers in the identification of T2D patients. However, more studies are needed for its implementation in clinical practice.

Analysis of the percentages of monocyte subsets and ILC2s, their relationships with metabolic variables and response to hypocaloric restriction in obesity

PURPOSE

Obesity results from excess energy intake over expenditure and is characterized by chronic low-grade inflammation involving circulating monocytes (Mo) and group 2 innate lymphoid cells (ILC2s) imbalance. We analyzed circulating Mo subsets and ILC2s percentages and β2-adrenergic receptor (β2AR) expression in lean and obese subjects, and the possible effect of hypocaloric restriction on these innate immune cells.

METHODS

In 139 individuals aged 45 to 57 years, classified in 74 lean individuals (>18.9kg/m2 BMI <24.9kg/m2) and 65 with obesity (n = 65), we collected fasting blood samples to detect Mo subsets, ILC2s number, and β2AR expression by flow cytometry. Lipids, insulin, leptin, and acylated-ghrelin concentrations were quantified. Resting energy expenditure (REE) was estimated by indirect calorimetry. These measurements were repeated in obese subjects after 7-weeks of hypocaloric restriction.

RESULTS

Non-classical monocytes (NCM) and β2AR expression on intermediate Mo (IM) were increased in obese individuals (p<0.001, in both cases), whereas the percent of ILC2s was decreased (p<0.0001). Stepwise regression analysis showed significantly negative associations of ILC2s with caloric intake, β2AR expression on IM with REE, but a positive relationship between NCM and HOMA-IR. Caloric restriction allowed a significant diminution of NCM and the β2AR expression on IM, as well as, an increase in the percent of classical Mo (CM), and ILC2s. ΔREE was related to ΔCD16+/CD16- ratio.

CONCLUSIONS

These findings show that in obesity occur changes in NCM, ILC2s and β2AR expression, which contribute to the low-grade inflammation linked to obesity and might revert with caloric restriction.

Relationship of lactation, BMI, and rs12255372 TCF7L2 polymorphism on the conversion to type 2 diabetes mellitus in women with previous gestational diabetes

Women with previous gestational diabetes mellitus (pGDM) have a high risk of developing postpartum type 2 diabetes mellitus (T2DM). This study aimed to analyze the relationship between lactation, BMI, and TCF7L2 polymorphisms in the conversion to T2DM in women with pGDM. One hundred and fifty-three women con pGDM were recruited from public hospitals of León Guanajuato México. Three groups: normal glucose tolerance (NGT), impaired glucose intolerance (IGT), and T2DM after the oral glucose tolerance test were formed. Metabolic and hormone variables were measured, and genotyping was made by PCR-RFLP. The questionnaire included data on lactation (yes/no), duration of lactation, and full lactation. After 35 (21-49) months from the last partum, 54% of women had an NGT, 30.7% IGT, and 15% T2DM. BMI and rs12255372 are associated with the risk of conversion to IGT and T2DM [OR = 1.07 (95% IC 1.0-1.14, p = .041; OR =2.14, 95% IC 1.01-4.55, p = .04 respectively), while the lactation shows a strong protective effects OR = 0.15 (95% IC 0.062-0.39, p = .00007), and an apparent interaction with rs12255372T decreasing the risk in carriers (OR =2.15; 95% IC 0.97-4.7, p = .05). BMI is an independent risk factor of IGT/T2DM development. The lactation shows a strong protective effect and a possible interaction with rs12255372 polymorphism.

Flow mediated vasodilation compared with carotid intima media thickness in the evaluation of early cardiovascular damage in menopausal women and the influence of biological and psychosocial factors

Background

Women after menopause increase risk for cardiovascular disease and several factors may be related. The purpose was to study biological and psychosocial factors associated with early cardiovascular damage in pre- and postmenopausal women, assessed with carotid intima-media thickness vs flow-mediated dilatation.

Methods

Women 45 to 57 years old were grouped in the pre- (n = 60), early (n = 58) and late post-menopause (n = 59). Anthropometric, metabolic and hormonal data were registered, as well as measures of depression, anxiety, submission, perceived stress, and sleep alterations. Heart Rate Variability was recorded to obtain the information regarding sympathovagal balance. Carotid intima-media thickness and flow-mediated dilatation were assessed by ultrasound. Two-way ANOVA and multiple regression model were used.

Results

At late postmenopause, the carotid intima-media was thicker (p < 0.001) and flow-mediated dilatation decreased (p < 0.001). Carotid intima-media thickness was associated positively with age (p < 0.001), submission score (p = 0.029), follicle stimulating hormone levels (p < 0.001), and body mass index (p = 0.009). Flow-mediated dilatation was associated only with age (p < 0.001). Regarding heart rate variability, the time domain pNN50 measurement was higher in premenopausal women (p = 0.001), Low Frequency (LF) was higher in the two groups of postmenopausal (p = 0.001) and High Frequency (HF) higher in the early postmenopausal women (p = 0.042).

Conclusions

Under our conditions carotid intima-media thickness had higher predictive value for early cardiovascular damage at menopause. The finding of the association of the submission score, indicates de influence of stress on vascular damage.

Leptin and its Receptors in Human Placenta of Small, Adequate, and Large for Gestational Age Newborns

Alterations in birth weight impact postnatal outcome and adult metabolic health. Therefore, fetal growth regulation is crucial for preventing chronic metabolic diseases. Leptin has been suggested to play an important role in placental and fetal growth, albeit its specific mechanisms of action have not been elucidated. The aim of this study was to analyze leptin concentrations in placenta, cord blood, and maternal blood of SGA, AGA, and LGA (small, adequate and large for gestational age, respectively) newborns, as well as placental leptin receptor (LEPRa and LEPRb) protein expression. We performed a cross-sectional comparative study in 3 groups of healthy mothers and their term newborns at delivery (SGA, AGA, and LGA, n=20 per group). Placental, maternal blood, and cord blood leptin content were measured by ELISA. Placental LEPRa and LEPRb protein expression were determined by Western Blot. Maternal leptin concentrations correlated positively with maternal weight before and at the end of gestation, without differences between groups. Cord leptin is higher in LGA and lower in SGA, whereas placental leptin is higher in SGA. Placental leptin was inversely correlated with placental weight, independently from maternal weight and gestational age. Both LEPRa and LEPRb expression are lower in SGA, while LEPRa positively correlated with placental weight and birthweight. The current findings indicate that placental leptin and its receptors are differentially expressed in SGA, AGA, and LGA newborns. We suggest that placental leptin and LEPR protein expression may influence placental growth and thus, birth weight.

Effect of Restriction of Foods with High Fructose Corn Syrup Content on Metabolic Indices and Fatty Liver in Obese Children

OBJECTIVE

We examined the effect of restriction of foods with high fructose content in obese school children.

METHODS

In a clinical study, we selected 54 obese children 6 to 11 years old with high fructose consumption (>70 g/day) in order indicate dietary fructose restriction (<20 g/day) for 6 weeks. Anthropometry, liver ultrasound as well as glucose, insulin, lipids, leptin, IGFBP1, and RBP4 serum levels were collected.

RESULTS

The group of children had 80% adherence and reported decreased fructose consumption (110 ± 38.6 to 11.4 ± 12.0 g/day) and also a significant decrease in caloric (2,384 ± 568 to 1,757 ± 387 kcal/day) and carbohydrate consumption (302 ± 80.4 to 203 ± 56.0 g/day). The severity of steatosis improved significantly after fructose restriction (p < 0.000001). However, no changes in BMI, systolic blood pressure, or diastolic blood pressure were found. Only triglyceride levels decreased (1.44 ± 0.43 to 1.31 ± 0.38 mmol/l), High-densitiy lipoprotein cholesterol showed a marginal increase (1.45 ± 0.19 to 1.56 ± 0.44 mmol/l). Insulin resistance and RBP4 did not change.

CONCLUSIONS

In school children, the restriction of high fructose foods with a decrease of caloric and carbohydrate intake at 6 weeks did not induce weight loss; however, triglyceride levels and hepatic steatosis decreased. Differences with other studies in regard to weight loss may be explained by adaptive changes on metabolic expenditure.

Effects of sleeve gastrectomy and rs9930506 FTO variants on angiopoietin/Tie-2 system in fat expansion and M1 macrophages recruitment in morbidly obese subjects

Angiogenesis in inflammation are hallmarks for adipose tissue expansion in obesity. The role of angiopoietin/Tie-2 system in adipose tissue expansion and immune cell recruitment is unclear. We studied the effect of sleeve gastrectomy and the influence of FTO rs9930506 polymorphism on Tie-2, angiopoietin-1 and angiopoietin-2 expression in morbid obesity. Fifteen morbidly obese subjects (4 men and 11 women) aged 24-55 years were followed-up 3 and 6 months after sleeve gastrectomy. Serum sTie-2, angiopoietin-1, angiopoietin-2, and hypoxia-inducible factor-1α concentrations were determined by ELISA. Tie-2 and its ligands in visceral and subcutaneous adipose tissue were localized by immunohistochemistry. Tie-2 expression was measured by flow cytometry in circulating monocytes and infiltrated macrophages. Comparisons before and after sleeve gastrectomy were carried out using ANOVA for repeated measures. rs9930506FTO genotyping was performed by PCR-RFLP. Circulating sTie-2 and angiopoietin-2 were higher before sleeve gastrectomy. Tie-2 and angiopoietin-2 mRNA levels were higher in subcutaneous adipose tissue than visceral and both decreased after surgery. Monocytes and infiltrated macrophages showed a pro-inflammatory phenotype, with increased Tie-2 expression that decreased 3 and 6 months after sleeve gastrectomy. Baseline sTie-2 correlated inversely with adiponectin levels. At baseline the rs9930506FTO AG ó GG genotypes carriers had more 34 kg than genotype carriers of rs9930506 AA. Weight and body mass index decreased at 6 months. We found that angiopoietin/Tie-2 system is mainly expressed in subcutaneous adipose tissue, contributing to expandability, fat accumulation, and monocytes attachment in obesity. Bariatric surgery favorably modifies the pro-angiogenic profile, allowed a reduced angiogenic expression in the circulation and adipose tissue.

Association of cord blood des-acyl ghrelin with birth weight, and placental GHS-R1 receptor expression in SGA, AGA, and LGA newborns

Although ghrelin in cord blood has been associated to birth weight, its role in fetal and postnatal growth has not been elucidated. The aim of this study was to analyze total ghrelin, acyl ghrelin (AG), and des-acyl ghrelin (DAG) in cord blood of newborns with idiopathic birth weight alterations, and to evaluate protein expression of placental GHS-R1, in order to investigate their correlation with birth weight and placental weight. We performed a cross-sectional comparative study in umbilical cord blood and placentas from healthy mothers of SGA, AGA, and LGA (small, adequate and large for gestational age) term newborns (n = 20 per group). Cord blood total ghrelin, AG, and DAG were measured by ELISA, and placental GHS-R1 expression was evaluated by Western blot. Cord blood DAG was higher in SGA compared to AGA newborns (902.1 ± 109.1 and 597.4 ± 58.2 pg/ml, respectively, p = 0.01) while LGA and AGA showed similar values (627.2 ± 76.4 pg/ml for LGA, p = 0.80). DAG negatively correlated with birthweight (r = -0.31, p = 0.02) and placental weight (r = -0.33, p = 0.02). No differences in AG or total ghrelin were found. GHS-R1 protein in placenta was not differentially expressed among SGA, AGA, and LGA. Our results suggest a role of DAG in intrauterine growth. Further studies are needed in order to elucidate the mechanisms by which DAG participates in fetal growth.

Dietary restriction in obese children and its relation with eating behavior, fibroblast growth factor 21 and leptin: a prospective clinical intervention study

BACKGROUND

Obesity is significant problem involving eating behavior and peripheral metabolic conditions. The effect of carbohydrate and fat restriction on appetite regulation, fibroblast growth factor 21 (FGF21) and leptin in children has not been defined. Our objective was to compare the effect of both diets.

METHODS

One hundred and twenty children with body mass index (BMI) higher than the equivalent of 30 kg/m(2) for an adult, as corrected for gender and age were randomly assigned to (n = 60) a low-carbohydrate (L-CHO) diet or (n = 60) a low-fat (L-F) diet for 2 months. Fifty-three (88.3 %) subjects on the low-carbohydrate-diet and 45 (75 %) on the low-fat diet completed the study. Anthropometric measures, leptin and FGF21 levels were measured before and after the intervention. Comparison of the data for both of the diet groups was carried out using the t-test for independent variables. Intragroup comparisons before and after of each of the dietary treatments were performed using ANOVA for repeated measures. Factors associated with FGF21, leptin levels and satiety, were analyzed by multiple regression.

RESULTS

After both of the diets, weight, leptin, food responsiveness, and enjoyment of food significantly decreased and high density lipoprotein cholesterol (HDL) increased, but FGF21 decreased. Before and after both of the interventions FGF21 was associated with triglycerides. Before the diet, satiety was associated with lower screen time (p < 0.04) and insulin levels (p < 0.05).

CONCLUSIONS

Both dietary restrictions improved the metabolic and hormonal parameters of obese children. FGF21 is an indicator of a beneficial metabolic response in younger children. After 2 months an adaptation of the eating behavior to food restriction was observed.

Influence of heart rate variability and psychosocial factors on carotid stiffness, elasticity and impedance at menopause

BACKGROUND AND AIMS

The risk for cardiovascular diseases (CVD) increases after menopause. Heart rate variability (HRV), a measure of autonomic control, is a strong predictor of CVD. We undertook this study to test the association of ultrasound indices of early carotid atherosclerosis with HRV, symptoms, hormonal conditions, metabolic state, indicators of stress, and psychosocial factors in women at peri- and postmenopause, registering ambulatory R-R interval monitoring.

METHODS

In a cross-sectional design we studied 100 women at peri- and early postmenopause collecting anthropometry, symptoms, stress-related measurements, metabolic variables, cortisol, FSH and estradiol. We evaluated carotid ultrasonographic indices, and HRV was recorded for 4 h calculating time (SDNN, pNN50, rMSSD) and frequency domains (LF, HF, LF/HF) in women according to menopausal stage, estradiol levels, body mass index and waist circumference.

RESULTS

Carotid indices were similar in peri- and postmenopausal women. For HRV measurements, SDNN was increased at postmenopause. Women with estradiol levels <109.2 pmol/L had increased intima-media thickness (IMT), resistive index, and systolic diameter. Using multivariate analysis, we found the associations of IMT positively with non-HDL-cholesterol, resistive index positively with LF-HRV, but negatively with effort/reward imbalance, carotid β stiffness index inversely with estradiol, and arterial distensibility positively with HF-HRV and creatinine concentrations, but negatively with non-HDL-cholesterol.

CONCLUSIONS

Carotid thickness was related mainly with lipid alterations. Indices of early carotid damage were related with various components of HRV as a manifestation of autonomic imbalance, indicating CVD risk. Other factors involved were time since last menses and psychological stress. Low creatinine was associated with diminished carotid distensibility. This suggests that estrogen, lifestyle, behavior and autonomic regulation participate in vascular damage.

Whole-body and hepatic insulin resistance in obese children

Background

Insulin resistance may be assessed as whole body or hepatic.

Objective

To study factors associated with both types of insulin resistance.

Methods

Cross-sectional study of 182 obese children. Somatometric measurements were registered, and the following three adiposity indexes were compared: BMI, waist-to-height ratio and visceral adiposity. Whole-body insulin resistance was evaluated using HOMA-IR, with 2.5 as the cut-off point. Hepatic insulin resistance was considered for IGFBP-1 level quartiles 1 to 3 (<6.67 ng/ml). We determined metabolite and hormone levels and performed a liver ultrasound.

Results

The majority, 73.1%, of obese children had whole-body insulin resistance and hepatic insulin resistance, while 7% did not have either type. HOMA-IR was negatively associated with IGFBP-1 and positively associated with BMI, triglycerides, leptin and mother's BMI. Girls had increased HOMA-IR. IGFBP-1 was negatively associated with waist-to-height ratio, age, leptin, HOMA-IR and IGF-I. We did not find HOMA-IR or IGFBP-1 associated with fatty liver.

Conclusion

In school-aged children, BMI is the best metric to predict whole-body insulin resistance, and waist-to-height ratio is the best predictor of hepatic insulin resistance, indicating that central obesity is important for hepatic insulin resistance. The reciprocal negative association of IGFBP-1 and HOMA-IR may represent a strong interaction of the physiological processes of both whole-body and hepatic insulin resistance.

Metabolic, hormonal characteristics and genetic variants of TCF7L2 associated with development of gestational diabetes mellitus in Mexican women

BACKGROUND

Variation in TCF7L2 gene is associated with type 2 diabetes and with gestational diabetes mellitus in several populations, but there are no data in Mexican women with gestational diabetes mellitus. In this study, we examined metabolic and hormonal measurements as well as TCF7L2 genetic variants.

METHODS

We selected 108 pregnant women with normal glucose tolerance and 90 with gestational diabetes mellitus according to 2010 American Diabetes Association criteria matched for gestational week. We collected data on blood pressure, body mass index (BMI) and concentrations of blood glucose, HbA1c , lipids profile, insulin and glucagon-like peptide-1 (GLP-1). The genotyping of rs7903146 and rs12255372 polymorphisms were made with polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

Actual and pre-gestational BMI, fasting glucose and HbA1c were higher (p < 0.001), and high-density lipoprotein cholesterol was lower (p < 0.02) in gestational diabetes mellitus women than euglycemic women. No significant differences were found for lipids, insulin and homeostasis model assessment-insulin resistance. Gestational diabetes mellitus women had high GLP-1 levels (32 vs 24, p < 0.004) and decreased β-cell function (266 vs 438, p < 0.001). The frequency of rs12255372 risk allele in gestational diabetes women was significantly higher than that in euglycemic women (χ²  = 8.96; p < 0.003) and confers a risk for gestational diabetes mellitus (OR = 9.1, 95% CI 2.8-29, p < 0.0002; and OR = 4.3, 95% CI 1.6-11.4, p < 0.003 based on dominant and co-dominant model, respectively). The generalized linear model showed that low beta function, high pre-gestational BMI and rs12255372 risk allele are independently associated with gestational diabetes.

CONCLUSIONS

The elevated GLP-1 levels in gestational diabetes women suggested some abnormality in insulin secretion. The low β-cell function, high pre-gestational BMI and rs12255372 risk allele are risk factors independently associated with the development of gestational diabetes.

Markers of the progression of complications in patients with type 2 diabetes: a one-year longitudinal study

Hyperglycemia induces tissue damage and complications by mechanisms that produce advanced glycation end-products (AGEs) and inflammation.To investigate the factors associated with the progression of complications in Type 2 diabetes patients.We recruited 157 patients (110 women and 47 men) with diabetes for more than 5 years who were non-smokers and did not have current infections or chronic diseases. Patients were grouped according to neuropathy, nephropathy, and retinopathy status: without (I), slight or moderate (II), and severe complications (III). We measured glucose, lipids and HbA1c, low molecular weight AGEs (LMW AGEs), high sensitivity C-reactive protein (CRP), TNF-α, IL-6, and malondialdehyde (MDA). Patients were re-evaluated 1 year later.Patients were 52.2±6.8 years old with 11.0±4.9 years since diagnosis. After 1 year, circulating AGEs increased (p<0.0001) and eGFR decreased (p<0.0007) in groups II and III. IL-6 and MDA decreased in groups I and II. CRP (p<0.029) and AGEs (p<0.0001) increased in group II. At baseline in group I, TNF-α levels were higher (p<0.002) in patients who later developed complications. In group II, TNF-α levels (p<0.015) and microalbuminuria (p<0.00004) were higher in patients whose complications progressed. Logistic regression analysis showed that complication progress was significantly associated with log(albuminuria) (p<0.004) and log(TNF-α) (p<0.008). In the total group, AGEs were associated with age (p<0.024) and HbA1c (p<0.026).Our results suggest that baseline TNF-α is an important predictor of complication progression in Type 2 diabetes patients. AGEs also increased during the deterioration of renal function after 1 year of follow-up observation.

Metabolic and nutritional profile differences among Mexican, Mexican-American and Non-Hispanic White children

OBJECTIVE

To compare somatometric variables, lipid profile, diet, and physical activity between Mexican children living in México (MEX), and Mexican-American (MXA) and Non-Hispanic White (NHW) children from the United States (US) to examine the possible influence of ethnicity and residency on these factors.

MATERIAL AND METHODS

Six to twelve years old children data from a study from central México and the US National Health and Nutrition Examination Survey was compared. Data were categorized to examine the effect of residency (MEX vs. MXA and NHW) and ethnicity (MEX vs. MXA and NHW) on the variables of interest.

RESULTS

Living in the US was associated with higher cholesterol levels in younger boys and older girls (p < 0.05), and high saturated fat intake in all groups (p < 0.0001). Living in México increased the likelihood of abnormal HDL (p < 0.001), systolic (p < 0.001), and diastolic blood pressure (p < 0.0001). Caucasian young girls were more likely to have high cholesterol intake (p < 0.02) than their Mexican counterparts.

CONCLUSIONS

These findings suggest that residency is linked to impaired lipid profile and blood pressure in children, whereas ethnicity seems to have an impact on dietary choices.

Analysis of the contribution of FTO, NPC1, ENPP1, NEGR1, GNPDA2 and MC4R genes to obesity in Mexican children

Background

Recent genome wide association studies (GWAS) and previous positional linkage studies have identified more than 50 single nucleotide polymorphisms (SNPs) associated with obesity, mostly in Europeans. We aimed to assess the contribution of some of these SNPs to obesity risk and to the variation of related metabolic traits, in Mexican children.

Methods

The association of six European obesity-related SNPs in or near FTO, NPC1, ENPP1, NEGR1, GNPDA2 and MC4R genes with risk of obesity was tested in 1,463 school-aged Mexican children (N_cases = 514; N_controls = 949). We also assessed effects of these SNPs on the variation of body mass index (BMI), fasting serum insulin levels, fasting plasma glucose levels, total cholesterol and triglyceride levels, in a subset of 1,171 nonobese Mexican children.

Results

We found a significant effect of GNPDA2 rs10938397 on risk of obesity (odds ratio [OR] = 1.30; P = 1.34 × 10^-3). Furthermore, we found nominal associations between obesity risk or BMI variation and the following SNPs: ENPP1 rs7754561, MC4R rs17782313 and NEGR1 rs2815752. Importantly, the at-risk alleles of both MC4R rs17782313 and NPC1 rs1805081 showed significant effect on increased fasting glucose levels (β = 0.36 mmol/L; P = 1.47 × 10^-3) and decreased fasting serum insulin levels (β = −0.10 μU/mL; P = 1.21 × 10^-3), respectively.

Conclusion

Our present results suggest that some obesity-associated SNPs previously reported in Europeans also associate with risk of obesity, or metabolic quantitative traits, in Mexican children. Importantly, we found new associations between MC4R and fasting glucose levels, and between NPC1 and fasting insulin levels.

Distribution of the homeostasis model assessment of insulin resistance in Mexican children and adolescents

OBJECTIVE

Several cutoff points of the homeostasis model assessment of insulin resistance (HOMA-IR; varying from 2.5 to 4.0) have been suggested for diagnosing IR in youth. In this study, we determined the distribution of the HOMA-IR in Mexican children and adolescents.

DESIGN AND METHODS

A total of 6132 children and adolescents from San Luis Potosi, León, Queretaro, and Durango, which are cities in central and northern Mexico, were enrolled in a population-based cross-sectional study. Eligible participants were apparently healthy children and adolescents aged 6-18 years. Pregnancy and the presence of chronic illnesses were exclusion criteria.

RESULTS

A total of 3701 (60.3%) girls and 2431 (39.7%) boys were included in this study. In the overall population, the mean body mass index, insulin levels, and fasting glucose levels were 21.8±1.3 kg/m(2), 7.1±3.2 μU/ml, and 86.2±10.0 mg/dl respectively. The concentrations of insulin and fasting glucose gradually increased from 6 to 12 years of age, whereas the concentrations tended to plateau in the 13- to 18-year-old population. The absolute mean of the HOMA-IR was 2.89±0.7. The HOMA-IR gradually increased with age and reached a plateau at 13 years of age.

CONCLUSIONS

Because the insulin concentrations, glucose levels, and HOMA-IR exhibited a gradual increase with age that was not related to obesity, our results suggested that the evaluation of IR in children should be based on percentiles of the HOMA-IR rather than a dichotomous value derived from a single cutoff point.

Association of the TNF-α -308G/A polymorphism with family history of type 2 diabetes mellitus in a Mexican population

AIMS

We examined the possible association of the -308G/A polymorphism of the TNF-α promoter gene in type 2 diabetes mellitus (DM2) patients and in non-diabetic subjects with and without family history of DM2.

METHODS

We studied 87 non-diabetic subjects without DM2 family history in at least one of two generations, 48 non-diabetic subjects with DM2 family history and 95 DM2 patients. Genotyping was carried out by PCR-RFLP.

RESULTS

The frequency of TNF-α -308G/A genotype was significantly lower in non-diabetic subjects without DM2 relatives (6%) as compared to DM2 patients (24%) (odds ratio (OR)=5.24; 95% confidence interval (CI)=1.9-15.8, p<0.0005), but similar to non-diabetic subjects with DM2 relatives (29%) (OR=0.77; CI=0.3-1.7, p=0.4). Logistic regression analysis showed the association of TNF-α -308G/A polymorphism with DM2 family history (OR=5.80; CI=1.77-18.98, p<0.0003).

CONCLUSIONS

Our results suggest that TNF-α -308G/A polymorphism is associated with DM2 family history and is a risk factor for DM2.

Coping strategies and adherence to treatment in patients with type 2 diabetes mellitus

INTRODUCTION

Diverse psychosocial and cultural factors are related to adherence to treatment of type 2 Diabetes mellitus (DM2) such as social support, coping styles and the cost of medical attention.

OBJECTIVE

To study the influence of diverse psychosocial factors on adherence to treatment in patients with DM2.

MATERIAL AND METHODS

In a cross sectional design we studied adherence to diet and medication, and its relationship with CS for diabetes, belief in conventional medicine, social support, and the perception of the burden of treatment cost on family finances.

RESULTS

We included 210 patients a mean age of 56.3 years, 9.4 years since diagnosis. Male DM patients had better adherence to medication (p<0.016) and social support (p<0.004), and higher rates for supportant CS (31.8 vs. 29.0; p<0.009). Adherence to diet was associated with belief in conventional medicine (p<0.035) and marginally related to fatalistic CS (p<0.05). After testing social security coverage as dummy variable, a marginal association was found (p<0.15). Adherence to medication was associated with supportant CS (p<0.02) and marginally with avoidant CS (p<0.05).

CONCLUSIONS

Supportant CS was more frequent in men. Belief in conventional medicine, and supportant CS were associated with adherence to treatment. These factors should be considered for a more rational approach for the management of disease.

TSH and free thyroxine concentrations are associated with differing metabolic markers in euthyroid subjects

OBJECTIVE

To examine the association between thyroid function and the components of the metabolic syndrome and insulin resistance in an Hispanic population.

DESIGN

Cross-sectional study.

METHODS

Subjects with no history of thyroid disease or diabetes were included. Thyroid function was stratified as euthyroid or subclinical hypothyroidism (SCH) status and subsequently by free thyroxine (FT(4)) and TSH tertiles. The association of the metabolic syndrome components (defined by 2004 Adult Treatment Panel III criteria) and insulin resistance with thyroid status, TSH, and FT(4) were examined.

RESULTS

A total of 3148 subjects were analyzed. The prevalence of SCH was 8.3%. The prevalence of the metabolic syndrome was similar in euthyroid and SCH patients (31.6 vs 32.06%, P=0.89). Total cholesterol was higher in patients with SCH (5.51+/-1.19 vs 5.34+/-1.05 mmol/l, P<0.032). Serum TSH values showed a positive correlation (adjusted for age and sex) with total cholesterol, triglycerides, and waist circumference. In contrast, FT(4) showed a positive correlation with high-density lipoprotein cholesterol, and an inverse correlation with waist circumference, insulin, and HOMA-IR.

CONCLUSION

SCH is not associated with an increased risk for the metabolic syndrome (as conceived as a diagnostic category defined by the National Cholesterol, Education Program, Adult Treatment Panel III criteria). Despite this, low thyroid function (even in the euthyroid state) predisposes to higher cholesterol, glucose, insulin, and HOMA-IR levels. The combined use of TSH and FT(4), compared with the assessment based on only FT(4), is a more convenient approach to evaluate the association between thyroid function and metabolic variables.

Relationship of aldosterone synthase gene (C-344T) and mineralocorticoid receptor (S810L) polymorphisms with gestational hypertension

The extent of genetic influence in the aetiology of gestational hypertension has not been completely determined. The aim of this study was to analyse the relationship between aldosterone levels and the -344T/C polymorphism of the aldosterone synthase gene (CYP11B2) and to investigate the frequency of the S810L mutation of mineralocorticoid receptor (MR) in gestational hypertension. One hundred women with pregnancy-induced hypertension and 100 with normal pregnancy were studied to measure serum aldosterone and progesterone levels and for the genotypification of the -344T/C polymorphism of CYP11B2 gene and the S810L mutation of MR by RFLP-PCR and SSP, respectively. Serum aldosterone levels were reduced (<0.000001) and serum progesterone levels increased (<0.000001) in gestational hypertensive women as compared with normal pregnant women. The -344T/C of CYP11B2 genotypic frequencies were similar in the hypertensive and normotensive pregnant women. The 810L-mutated allele of MR was found in 12% of the hypertensive and 9.4% of the normotensive pregnant women. In contrast to the observations made in preeclampsia, the genotype of -344T/C of CYP11B2 was neither related with gestational hypertension nor with aldosterone levels at delivery. The frequency of the S810L mutation was similar in the hypertensive and normotensive women but higher than observed in other reports.

Induction of tolerance in renal transplantation using splenic transplantation: experimental study in a canine model

OBJECTIVE

To evaluate in a canine model the induction of tolerance to renal transplantation after splenectomy and splenosis.

MATERIALS AND METHODS

This prospective, experimental, comparative, longitudinal study included 4 experimental groups, each comprising 4 dogs. Group 1 (control group) underwent renal transplantation only; group 2 underwent renal transplantation and splenectomy; group 3 underwent renal transplantation and splenosis; and group 4 underwent renal transplantation, splenectomy, and splenosis. Survival and degree of rejection were compared between the 4 groups.

RESULTS

Splenosis improved renal function after transplantation, as indicated by increased serum creatinine concentration (group 3, 6.2 mg/dL vs group 1, 12.9 mg/dL). Comparison of weighted survival curves (corrected for degree of rejection) demonstrated a significant difference between group 2 (66.0 days) and group 4 (66.2 days) vs group 1 (52.7 days) and group 3 (41.2 days) (P = .05, Wilcoxon rank sum test).

CONCLUSION

These results suggest that in this experimental model of renal transplantation, splenosis and splenectomy induce clinical tolerance, as indicated by improved renal function and prolonged recipient survival.

Ghrelin in small-for-gestational age (SGA) newborn babies: a cross-sectional study

BACKGROUND

Small-for-gestational newborn babies may have long-term metabolic consequences. Among the main hormones possibly involved in foetal growth regulation are the IGFs, IGFBPs and the recently described ghrelin.

OBJECTIVE

To examine the levels of desacyl-ghrelin, IGF-1, IGFBP-1 and IGFBP-3 in children Small-for-gestational age (SGA) and children adequate-for-gestational age (AGA).

DESIGN

This was a cross-sectional and comparative study.

SUBJECTS

We included 40 children SGA and 40 children AGA.

MEASUREMENTS

Blood sample was taken a week after birth and measuring hormonal levels were done by ELISA.

RESULTS

SGA babies had lower IGF-1, IGFBP-3 and leptin levels, but higher ghrelin and IGFBP-1 levels. Birth weight was associated independently with ghrelin and IGFBP-1 (negatively) and IGFBP-3 (positively). Ghrelin circulating levels were associated negative and independently with IGFBP-3 and triglycerides in the mother.

CONCLUSIONS

We interpreted these findings to indicate that diminished body weight in newborns induce different adaptive signals, some of them mediated by IGF-1/IGFBP-3, ghrelin or by IGFBP-1. This regulation is congruent with the proposed role of ghrelin to adaptation to under-nutrition favouring lipid accumulation. CONCyTEG grant number 05-16-K117-028.

Expression of estrogen receptor alpha and beta in breast cancers of pre- and post-menopausal women

Expression of estrogen receptors (ER) is clinically relevant in designing therapeutic strategies. The relative importance of the two types of estrogen receptors (ER-alpha and ER-beta) in human breast cancers in pre- and post-menopausal women has not been properly defined. To determine the possible association between the expression of estrogen receptor and serum estradiol levels in pre- and post-menopausal women with breast cancer. 44 patients with invasive ductal carcinoma of the breast were studied and a breast tissue biopsy was taken. ER-alpha and ER-beta were detected by immunocytochemistry. Serum levels of estradiol and estrone were measured by radioimmunoassay and FSH was measured using IRMA. We studied 21 pre- and 23 post-menopausal women with breast carcinoma. Examining the number of cases with tumors positive for ER, we found no differences in the frequency of ER-alpha between pre- and post-menopausal women, but ER-beta decreased marginally after menopause (p < 0.051). In cases with tumors positive for ER, the proportion of cells positive for ER-alpha was similar post-menopausally (53.95%) and pre-menopausally (57.21%), but for ER-beta the number of positive cells decreased significantly after menopause (p < 0.051). In pre-menopausal women there was a correlation between serum estradiol levels and ER-beta; in post-menopausal women there was a correlation between serum FSH levels and ER-alpha. These results indicate that estradiol levels in women with mammary carcinoma are related to ER-beta expression in the breast tumor tissue.

Telomerase activity, estrogen receptors (alpha, beta), Bcl-2 expression in human breast cancer and treatment response

Background

The mechanism for maintaining telomere integrity is controlled by telomerase, a ribonucleoprotein enzyme that specifically restores telomere sequences, lost during replication by means of an intrinsic RNA component as a template for polymerization. Among the telomerase subunits, hTERT (human telomerase reverse transcriptase) is expressed concomitantly with the activation of telomerase. The role of estrogens and their receptors in the transcriptional regulation of hTERT has been demonstrated. The current study determines the possible association between telomerase activity, the expression of both molecular forms of estrogen receptor (ERα and ERβ) and the protein bcl-2, and their relative associations with clinical parameters.

Methods

Tissue samples from 44 patients with breast cancer were used to assess telomerase activity using the TRAP method and the expression of ERα, ERβ and bcl-2 by means of immunocytochemical techniques.

Results

Telomerase activity was detected in 59% of the 44 breast tumors examined. Telomerase activity ranged from 0 to 49.93 units of total product generated (TPG). A correlation was found between telomerase activity and differentiation grade (p = 0.03). The only significant independent marker of response to treatment was clinical stage. We found differences between the frequency of expression of ERα (88%) and ERβ (36%) (p = 0.007); bcl-2 was expressed in 79.5% of invasive breast carcinomas. We also found a significant correlation between low levels of telomerase activity and a lack of ERβ expression (p = 0.03).

Conclusion

Lower telomerase activity was found among tumors that did not express estrogen receptor beta. This is the first published study demonstrating that the absence of expression of ERβ is associated with low levels of telomerase activity.

Factors associated with estrogen receptors-alpha (ER-alpha) and -beta (ER-beta) and progesterone receptor abundance in obese and non obese pre- and post-menopausal women

There is scarce information about the factors associated with estrogen receptors (ER) at menopause. In 113 volunteers pre- and post-menopausal healthy women, grouped as with and without obesity, estrogen receptors-alpha and -beta, and progesterone receptor (PR) were measured by immunohistochemistry in skin punch biopsies obtained from the external gluteal area. In pre-menopausal women, biopsies and a blood sample were performed between days 7 and 14 of the cycle. Serum hormone levels were measured by immunoradiometric assay or radioimmunoassay. After menopause, ER and PR amounts decreased significantly. At pre-menopause, obese women had lower PR levels than non obese (P<.006). In the post-menopausal group, obese women showed higher ER-alpha (P<.03) and ER-beta (P<.02) levels than the non obese group. In the analysis of factors associated with the amount of steroid receptors for the total group, log[ER-alpha], log[ER-beta], and log[PR] were associated with age (P<.002, <.005, and <.004, respectively). The log[ER-alpha] was also associated with log[FSH] (P<.0008); meanwhile, the log[PR] showed a marginal correlation with log[FSH]. In pre-menopausal women no factor associated with any of the three receptors was found. In post-menopausal women log[ER-alpha] was associated with log[estrone] and log[DHEAS] (P<.003 and <.02, respectively). log[PR] was associated with BMI (P<.002), years since menopause (P<.05), and log[DHEAS] (P<.003). We concluded that ER and PR diminish sharply at post-menopause. At this stage the amount of receptors depends on several factors such as BMI, years since menopause, and androgen precursors.

[Breast density and its association to polimorphism of the estrogen-receptor alpha gene Pvull and Xbal]

OBJECTIVE

To study the influence of ER-alpha on mammographic density.

MATERIAL AND METHODS

We selected 87 healthy women (age 49.8 +/- S.D. 6.12 years). We obtained the body mass index (BMI), and a fasting blood sample for hormone determinations and DNA extraction. ER-alpha genotyping was carried out by PCR and digestion with a Pvull and Xbal restriction endonucleases. Mammographic density was assigned by the radiologist used three categories of fatty, average and dense.

RESULTS

Mammographic density was significantly associated with estradiol (p = 0.04), estrone (p = 0.04), and FSH (p = 0.02). The BMI was not associated with Pvull and Xbal genotypes and marginally with mammographic breast density (p = 0.06).

CONCLUSIONS

We did not observe compelling evidence of an association between variant alleles of genotypes estrogen receptors alpha and breast density.

Advanced glycosylation end products in skin, serum, saliva and urine and its association with complications of patients with type 2 diabetes mellitus

BACKGROUND

The accumulation of advanced glycation end products (AGEs) has a key role in the pathophysiology of diabetes complications. Comparison of AGEs measurement in serum, skin, saliva and urine has not been reported.

AIMS

To compare AGEs in serum, skin, saliva and urine in patients with Type 2 diabetes mellitus, with complications at different stages.

MATERIALS AND METHODS

We examined 50 patients with Type 2 diabetes mellitus (40 women and 10 men) grouped according to the progression of neuropathy, nephropathy and retinopathy. The AGEs content in serum, skin, saliva and urine was measured by spectrofluorometry HPLC.

RESULTS

The patients had a mean age of 56.5 +/- 7.7 yr and 12.8 +/- 6.7 yr since diagnosis. AGEs in skin correlated with years since diagnosis (p = 0.0005). AGEs in serum, skin and saliva increased with the progression of complications, nevertheless, in urine a trend to diminution was found. In the group with end-stage renal disease (ESRD), AGEs in serum increased in greater proportion. In order to account for the decreased AGEs clearance, we corrected the values for creatinine levels, and AGEs in skin gave a better association with complications.

CONCLUSIONS

The AGEs measurement in skin, serum and saliva are useful to evaluate diabetes complications. AGEs in skin are associated with years since diagnosis of diabetes. Correction for renal function might discriminate AGEs in situ formation from accumulation.

Homeostatic model assessment and risk for hypertension during pregnancy: a longitudinal prospective study

The purpose of this study was to determine the association between insulin resistance and hypertension during pregnancy with the homeostatic model assessment (HOMA-IR). A longitudinal prospective study was carried out. One hundred sixty normotensive pregnant women were followed from the first trimester until delivery. HOMA-IR levels were determined each trimester. Statistical analysis included one-way analysis of variance and multivariate logistic regression. At follow-up, 134 women (83.8%) remained normotensive, 18 (11.2%) developed gestational hypertension, and 8 (5%) developed preeclampsia. At first trimester, HOMA-IR levels were higher in women who developed gestational hypertension (2.1 +/- 0.2) than in women who developed preeclampsia (1.2 +/- 0.0), or remained normotensive (1.2 +/- 0.3); p < 0.01. In the logistic regression analysis, HOMA-IR levels at first trimester were statistically significant ( p = 0.03) to predict development of gestational hypertension. Our results support the use of the HOMA-IR as an alternative index for the assessment of the risk for hypertension during pregnancy.

The relationship of estrogen receptor-α polymorphism with symptoms and other characteristics in post-menopausal women

OBJECTIVES

To study the influence of the estrogen receptor-alpha (ER-alpha) genotypes (PvuII and XbaI polymorphisms) on symptoms and bone density.

METHODS

We recruited 177 post-menopausal women to register hot flashes, vaginal dryness, depression, anxiety, sleep alterations, and serum hormones (FSH, LH, estrone, and estradiol). Bone mineral density (BMD) was measured with a radiographic method, correcting with an external reference. ER-alpha genotyping was carried out by PCR.

RESULTS

Scores for vaginal dryness were lower for the xx (P = 0.003), and pp genotypes (P = 0.006). Hot flashes were lower for the Pp (P = 0.006) genotype. FSH circulating levels were lower for Xx genotype (P = 0.036). The factors associated with BMD were estrone (P > 0.000001), estradiol (P = 0.0035) and XbaI (P = 0.035). Vaginal dryness, was associated with PvuII and XbaI polymorphisms (P = 0.037 and P = 0.039). Depression was associated with log(estrone) (P = 0.011), schooling (negatively, P = 0.012), and marginally with BMI (P = 0.066). Sleep alterations correlated with log(estrone) (P = 0.014) and marginally with years since menopause (P = 0.046). Anxiety correlated with schooling (negatively, P = 0.006) and age (p = 0.015), and hot flashes with schooling (negatively, P = 0.014). BMD was associated with log(estrone) (p < 0.000001), estradiol (negatively, P = 0.0036), and marginally with XbaI (P = 0.036).

CONCLUSIONS

In post-menopausal women, the ER-alpha polymorphism was associated with vaginal dryness, and hot flashes but not with other physical or emotional symptoms. Extraglandular estrogen production, and diverse molecular factors related to estrogen action may play an important role in this process.

Leptin and heart sympathetic activity in normotensive obese and non-obese subjects

BACKGROUND

In rats leptin increases sympathetic activity, and an inhibitory effect on leptin synthesis and release has been demonstrated for the catecholamines, both in adipocyte cell cultures and in healthy experimental animals. The aim of this study was to evaluate the relationship between leptin and heart sympathetic activity as well as changes in leptin levels after the administration of drugs that modify sympathetic activity.

METHODS

We performed a randomized, blinded, before-after trial in 81 normotensive obese and non-obese subjects. They were studied before and after treatment with enalapril (5 mg every 12 hours) or clonidine (0.1 mg every 12 hours) for 7 days.

RESULTS

Obese subjects had higher values for percent body fat (p < 0.0005), triglycerides (p < 0.05), leptin (p < 0.0005), and low frequency/high frequency ratio at night (LF/HFn, p = 0.05). After enalapril or clonidine treatment, leptin levels were not modified. Both drugs significantly diminished the systolic and diastolic blood pressures. In the obese group, clonidine and enalapril diminished the LF/HFn ratio (p < 0.05). The LF/HF index showed a univariate correlation with body mass index, leptin, systolic blood pressure, insulin, age and triglyceride levels. In the multiple regression analysis for factors associated with the LF/HF ratio, only leptin, age and insulin were included in the model. The r2 of the model was 0.3 (p = 0.0003).

CONCLUSIONS

A higher level of heart sympathetic activity is found in normotensive obese as compared with non-obese subjects. Both clonidine and enalapril reduced heart sympathetic activity in obese subjects without a change in fasting leptin levels.

Protective effect of DRB1 locus against type 2 diabetes mellitus in Mexican Mestizos

The aim of the study was to investigate the participation of human leukocyte antigen (HLA) class II alleles in the expression of type 2 diabetic and in nondiabetic subjects with and without family history of diabetes. The purpose was to evaluate any HLA association and to look for different patterns of insulin resistance and insulin secretion, comparing subjects with a low probability of developing diabetes, as a result of their family history. We recruited 87 healthy subjects without family history of diabetes, 48 healthy subjects with family history, and 47 type 2 diabetic patients. All of them were Mexican Mestizos of central Mexico. Using a standard 75-g oral glucose tolerance test, insulin resistance was determined and insulin secretion was assessed with the HOMA model. DRB1, DQA1 and DQB1 alleles were typed using polymerase chain reaction-sequence-specific oligonucleotide probe (PCR-SSOP) and sequence specific primers (PCR-SSP). Nondiabetic subjects had similar HOMA-IR and DeltaI 30/DeltaG 30 index (HOMA). A significant decreased frequency of DRB1*0403 (p = 0.01; odds ratio [OR] = 0.20) was demonstrated in type 2 diabetic patients, and DRB1*0701 (p = 0.02; OR = 0.17) in nondiabetics with family history of diabetes. These alleles associated with protection against type 2 diabetes, share glutamic acid at position-74 and were previously demonstrated to contribute to protection against type I diabetes.

Symptoms at pre- and postmenopause in rural and urban women from three States of Mexico

OBJECTIVES

We studied the possible influence of modern cultural conditions on symptoms at menopause in three distant populations, comparing urban vs. rural women from three different States of Mexico: Guanajuato, Coahuila and Yucatán. In these groups we compared the age at menopause and symptoms at pre- and postmenopause.

METHODS

A total of 7632 volunteers were selected from Guanajuato, Coahuila and Yucatán. In house visits, an oral questionnaire was applied to women 45-60 years old, non-pregnant or lactating, without hysterectomy, chronic illness, or hormone treatment. We collected general and personal data, clinical, somatometric variables, and symptoms: hot flashes, vaginal dryness, dispareunia, and diminished sexual interest. Depressive mood and anxiety were evaluated with the Hamilton-Bech-Rafaelsen Scale.

RESULTS

The mean age at menopause was 48.0 years. A logistic regression identified the association of age at menopause with urban or rural residence, and the State of origin. Scores for depression and anxiety were lower in Yucatán, and they were higher in rural women. Hot flashes, vaginal dryness and the diminished sexual interest were increased at postmenopause. Hot flashes varied from 73 to 32%, and were associated with menopause, low schooling, rural residence, body mass index (BMI), and State of residence. Similar factors were associated with vaginal dryness, dispareunia, and loss of sexual interest. Depressive mood was associated with rural residence, State of residence, menopause, high BMI, smoking habit, age, and schooling. Anxiety was associated with menopause, rural residence, low schooling, high BMI, and age. The loss of sexual interest was associated with age, BMI, menopause and number of pregnancies.

CONCLUSIONS

The frequencies of symptoms at menopause have similar ranges to other countries. Ethic and socio-cultural and environmental factors are involved in the appearance or symptoms.

Possible adverse effect of chromium in occupational exposure of tannery workers

Our aim was to investigate the adverse effects of occupational exposure to trivalent chromium. We measured chromium and iron levels in serum and urine and hemoglobin levels in tannery workers and unexposed persons. We studied three groups of subjects. Group 1 included 15 non-smoking male tannery workers highly exposed to chromium from tanning and retanning departments. Group 2 included 14 non-smoking male tannery workers with moderate chromium exposure from dying, drying and finishing departments. Group 3 included 11 healthy, non-smoking male subjects without direct chromium exposure. Higher serum chromium levels were observed in groups 1 and 2 with respect to group 3 (mean values respectively: 0.43; 0.25 and 0.13 microg x l(-1)). Urine chromium levels in group 1 were higher than those in controls (mean values: 1.78 and 1.35 microg x l(-1)). In group 1 an inverse association was found between serum chromium and urine iron (-0.524), urine chromium and hemoglobin (-0.594) and between the urine chromium to iron ratio and hemoglobin (-0.693, p<0.05). The results suggest a chromium adverse effect on iron metabolism, possibly associated with excessive body chromium accumulation. In conclusion, chromium urine test could be recommended for diagnosis of chromium adverse effect on iron metabolism. Further studies are needed to quantify the relationship between urine chromium and hemoglobin metabolism.

Gonadotropins at menopause: the influence of obesity, insulin resistance, and estrogens

Obese, postmenopausal women have lower FSH levels. To determine whether this is due to higher estrogen exposure, we compared feedback gonadotropin sensitivity and its relation to insulin resistance in four groups of obese and lean, postmenopausal women. Group one was treated with 400 mg troglitazone (TG) daily for two weeks; 150 clomiphene citrate (CC) was added daily for the second week. Group two received 150 mg CC daily for a week. Group three received 1000 mg metformin (MET) daily for two weeks, with 120 mg raloxifene (RAL) added during the second week. Group four received 120 mg RAL for a week. Before and after each period, a serum pool was obtained from samples taken every minute during a 10 ml interval. The women recruited for this study were categorized as obese or lean based on BMI >/= 29 or BMI < 29, respectively. Obese, menopausal women had lower FSH (45.5 IU/l) and LH (16.2 IU/l) values than those of lean (64.1 IU/l and 23.0 IU/l), but the obese menopausal women had higher leptin, DHEAS, glucose, insulin, and HOMA-IR levels. Log [FSH] was associated with BMI (r = -0.53, P < 0.000001) and number of pregnancies (r = -0.37, P = 0.0009). TG treatment did not change HOMA-IR or gonadotropin levels, but DHEAS and androstenedione levels decreased significantly. CC alone or together with TG, diminished FSH (-7.9 and -9.2) and LH (-2.5 and -3.6) concentrations, with a greater reduction in lean women. MET reduced glucose and the HOMA-IR index without affecting gonadotropin or steroid levels.

CONCLUSIONS

obese, menopausal women have lower FSH levels due to greater estrogen exposure, by mechanisms unrelated to insulin resistance.

Renal functional reserve in patients with recently diagnosed Type 2 diabetes mellitus with and without microalbuminuria

BACKGROUND/AIMS

During the first 10 years, two thirds of the patients with type 2 diabetes mellitus (DM) have microalbuminuria (MA). Functional renal reserve (FRR) and its relationship with proteinuria and metabolic control are unknown at the early phases of disease. We investigated the frequency of MA in recently diagnosed type 2 DM patients, and its association with FRR.

METHODS

We studied 181 type 2 DM patients with less than 6 months since diagnosis. Renal volume, MA, glomerular filtration rate (GFR) and renal plasma flow (ERPF) were evaluated before and after an acute oral protein load in 28 type 2 DM patients (14 with, and 14 without MA), and in 7 healthy subjects.

RESULTS

A total of 10.6% of the patients had MA. MA patients had higher cholesterol and triglyceride levels than those normoalbuminuric. Twenty recently diagnosed type 2 diabetic patients showed high basal GFR. Twelve of them had MA and insulin resistance. After the acute oral protein load, the control subjects and the patients without MA increased their GFR and their ERPF. The group with MA did not.

CONCLUSIONS

Seventy-five percent of the patients were hyperfiltering. Normoalbuminuric patients had larger increase in GFR and ERRPF than MB patients. We conclude that FRR measurement can be an important tool for the diagnosis of latent diabetic nephropathy.

Clinical and radiological improvement of periodontal disease in patients with type 2 diabetes mellitus treated with alendronate: a randomized, placebo-controlled trial

BACKGROUND

Alendronate (ALN) is an aminobisphosphonate commonly used for osteoporosis in postmenopausal women. We studied the effect of ALN on bone loss prevention in type 2 diabetes mellitus patients with periodontal disease.

METHODS

In a controlled double-blind, randomized study we evaluated prospectively diabetic patients paired by gender and years since diagnosis for 6 months. The study included 40 patients (20 men and 20 women), 50 to 60 years old, with more than 5 years since diagnosis of diabetes and established periodontitis. They were randomly allocated to alendronate (10 mg/daily) or placebo treatment for 6 months. The endpoints of treatment were: the distance between the alveolar bone border and the cemento-enamel-junction (CEJ) evaluated by means of digital radiographic imaging, a biochemical marker of bone resorption (urine N-telopeptide) (Ntx), and periodontal parameters. Metabolic control was assessed at baseline and after 6 months.

RESULTS

Baseline and 6-month glycated hemoglobin levels were similar in both groups. Alendronate induced a significant decrease in NTx at 6 months (P = 0.006). Periodontal parameters improved in both groups. However, they were significantly better for the ALN treated group. Alveolar bone border-CEJ distance increased in the placebo, but decreased in the ALN group (P = 0.0003).

CONCLUSIONS

In type-2 diabetic patients, alendronate induced more improvement in alveolar bone crest height than control therapy. No differences in urinary N-telopeptide or glycated hemoglobin were observed in this short-term randomized controlled pilot trial.

Contribution of HLA class II genes to end stage renal disease in mexican patients with type 2 diabetes mellitus

To analyze the contribution of MHC class II genes in type 2 diabetes mellitus (DM) with end stage renal disease (ESRD), we examined the distribution of HLA-DRB1, DQA1, DQB1 loci in Mexican Mestizos of Central Mexico, using PCR-SSOP and PCR-SSP. Three groups were included: 47 type 2 diabetic ESRD patients; 42 patients with ESRD and 50 type 2 DM patients with no kidney complication. The results were compared with those of 101 controls of the same area. The median since DM was first diagnosed, was 18 years prior to the onset of ESRD. The frequencies of DRB1*1502 and DQB1*0501 were increased in DM patients with ESRD (p = 0.004; RR = 7.4, CI = 1.5-37; EF = 0. 13; p = 0.007; RR = 2.9, CI = 2.3-3.5, EF = 0.21, respectively). In contrast, DRB1*0407 was decreased in the same group (p = 0.0008, RR = 0.2; CI = 0.035-0.70, PF = 0.19). Diabetic patients with DRB1*1502 are 8.8 times more likely to develop ESRD, independently of the duration time of DM. DRB1*1502 contributes to the susceptibility to ESRD while DRB1*0407 is involved in protection. The residue at DRB1-74 differs in these alleles: DRB1*0407 has glutamic acid and DRB1*1502 has an alanine, suggesting that this substitution may be important for both, peptide anchoring and for presentation to the T cells.

Perceived psychological stress in diabetes mellitus type 2

We studied the factors associated with perceived psychosocial stress in patients with diabetes mellitus type 2. A cross-sectional study was carried out in 105 patients (27 men and 78 women) with a mean age of 51.6 (50.2-52.5, 95% CI) years and 8.6 (7.3-9.8, 95% CI) years since diagnosis. The patients were overweight with body mass index (BMI) of 27.6, and most of them had deficient metabolic control (mean glucose of 10.6 nmol/L and HbA1c of 9.2%). Glycated hemoglobin was associated with BMI (negatively, p = 0.002), with adherence to diet (negatively, p = 0.027) and with years since diagnosis (p = 0.031). The association with BMI was found only in women. It was explained by the fact that obese women had fewer years since diagnosis, and recently diagnosed patients have a better metabolic control. A stepwise multiple regression analysis showed perceived stress associated with percent body fat and blood glucose in the total group, with years since diagnosis in women (p = 0.02), and with BMI in men (p = 0.03). No association was found between perceived stress and adherence to treatment. We concluded that in our group, perceived stress was associated with obesity and metabolic control.

Plasma epinephrine and norepinephrine response to stimuli in autonomic neuropathy of type 2 diabetes mellitus

The objective of this study was to examine epinephrine and norepinephrine plasma levels in patients with clinical type 2 diabetes mellitus, at different stages of autonomic neuropathy. Eighteen patients were classified in groups without (n = 6) and with early (n = 6), definite (n = 3) and severe (n = 3) neuropathy. Blood catecholamine levels were measured after the Valsalva maneuver, cold exposure and orthostatic tests. The norepinephrine basal levels were lower in patients with severe neuropathy (0.4 +/- 0.2 nmol/l), compared with the group with no neuropathy (1.3 +/- 0.5 nm/l, p = 0.034), or with early neuropathy (1.3 +/- 0.7 nm/l, p = 0.035). After the Valsalva maneuver, no increase was found in the group with severe alteration. In patients without neuropathy, cold exposure induced a peak of norepinephrine at 5 min (delta = 1.9 +/- 1.6 nmol/l). The increase was lower in groups with definite and severe damage. In patients with definite or moderate neuropathy, the orthostatic test induced minimal or no response. The epinephrine response to the maneuvers was not significant, and no differences were found among the groups. Norepinephrine basal levels and cold responses are diminished in patients with definite and severe autonomic neuropathy. This provides further evidence on their impaired response to stress. The comparable epinephrine levels in patients with or without autonomic neuropathy indicates that adrenal medullar function is not significantly altered.

Factors associated with the sexual experiences of underprivileged Mexican adolescents

This study investigated factors associated with the sexual experiences of 523 underprivileged Mexican adolescents. Approximately 41% of the males and 24% of the females were sexually active, with more than half not using contraceptives. Multivariate logistic regression analysis revealed that sexual activity was strongly associated with age, knowledge about sexually transmitted diseases, and attitudes toward sexuality. Positive affective responsiveness in the family was associated with sexual activity and number of sexual partners. Family problem solving and roles were also associated with sexual activity. The use of contraceptives was negatively related to affective involvement between parents, and being a victim of sexual abuse was negatively associated with number of persons in the family. These findings support the notion that affective environment within the family is a factor in adolescent sexuality.

Age at menopause in women with type 2 diabetes mellitus

OBJECTIVE

Considering that chronic diseases such as diabetes mellitus (DM) may determine premature ovarian failure by various mechanisms, we studied the age at menopause in women without diabetes and in women with type 2 DM.

DESIGN

We studied 409 women without diabetes and 404 patients with type 2 DM, selected from 45 to 55 years of age, for analysis with the status quo method. The age at menopause was calculated with a logistic regression on the proportions of menopausal women for each age group.

RESULTS

In the groups, 172 women without diabetes and 207 women with diabetes had menopause. The regression procedure gave a median age of 49.7 +/- SD 1.7 years for the whole group, 49.6 +/- 1.6 years for the nondiabetic group, and 49.8 +/- 1.7 years for women with diabetes. Women without diabetes were 1.4 years younger, but this factor did not have an influence on the results. Smoking habits, vegetarianism, and somatometric variables were similar in both groups, except for waist/hip and abdomen/hip ratios, larger in the group of women with diabetes. The mean for years since diagnosis in patients < 45 years of age was 4.9 years. For older patients, the figure increased to 8.9 years.

CONCLUSIONS

No difference for age at menopause was found between women without diabetes and women with type 2 diabetes who were 5 to 8 years since the diagnosis was made.

Denial of disease in Type 2 diabetes mellitus: its influence on metabolic control and associated factors

AIMS

We have investigated denial of disease in patients with Type 2 diabetes mellitus (DM) and its possible association with metabolic control, and with psychosocial variables: satisfaction with medical care, perceived stress, social support, knowledge of diabetes and belief in conventional medicine.

METHODS

We studied 160 patients in a cross-sectional design, in two groups: with (70) and without social security coverage (90). The mean age for the total group was 53.6 years, with a known diabetes duration of 8.1 years.

RESULTS

Denial of disease was similar in those with < or = 5 years since diagnosis (73 patients) and with > 5 years (87). The group without social security had higher scores of perceived stress, and lower scores of social support, knowledge about diabetes and belief in conventional medicine; denial, however, was similar in the two groups with or without social security. Multiple regression analysis showed that denial of disease was positively associated with HbA1c in the total group (P < 0.001), in the groups with < or = 5 and > 5 years since diagnosis, as well as in the groups with or without social security. Denial was also associated with years since diagnosis (P = 0.009) for the group with < or = 5 years since diagnosis.

CONCLUSIONS

We concluded that, in patients with Type 2DM denial of disease increases with time during the first 5 years of evolution of diabetes; is associated with poor metabolic control; but is not associated with knowledge of diabetes, belief in conventional medicine, social support or perceived stress.

[Anemia and iron deficiency in 490 Mexican pregnant women]

OBJECTIVE

To explore correlations of sociobiological variables with levels of blood hemoglobin (HB) in 490 pregnant women.

SETTING

Women attending private practice and two public hospitals in the city of Leon, State of Guanajuato (1800 m above sea level).

MATERIAL AND METHODS

Demographic, obstetric, nutritional and socioeconomic data were obtained together with an EDTA-blood sample for CBC, and serum for metabolite assays. The women had a mean gestation of 25 weeks (range 4-40) and 65% were multiparous with a mean parity of 2.1. By Mexican standards they had fairly high social, nutritional and intergenesic lapse. Associations were explored by step-wise multiple ANOVA.

RESULTS

On the basis of HB < 12 g/dL (equivalent aprox to 11 at sea level), 37% of the women were considered anemic. The MANOVA (excluding iron deficiency) showed associations of HB with gestation (p < 0.001) and parity (p = 0.024). Iron deficiency was present in 76% of the anemics (136/180) and 31% of the non-anemics (97/310). Folate and vitamin B12 assays in women with anemia and no iron deficiency showed folate or B12 deficiency in only 33% (14/43) leaving 29 cases with anemia of unknown etiology.

CONCLUSIONS

1. Gestation age was the factor most strongly associated to anemia and iron deficiency in our sample. 2. Anemia and iron deficiency were seen in 37% (N = 180) and 48% (N = 233) of the women respectively. 3. Of the 180 anemic women, 76% (N = 136) were iron deficient but only 14/43 anemic without iron deficiency were folate or B12 deficient leaving 6% (29/490) with anemia of unknown etiology. 4. The prevalence of anemia and iron deficiency were high in our population in spite of its fairly good sociodemographic and nutritional conditions.

High-frequency FSH and LH pulses in obese menopausal women

We studied the pulsatile luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretory patterns, at early or intermediate years of menopause in seven normal women with different degrees of obesity, taking blood samples every minute for 40 min to 2 h. The hormones were assayed with an immunoradiometric assay (IRMA) system, analyzing with the cluster pulse algorithm. All women showed hormone pulses every 8-10 min. In five of them were found periods of discrete pulses with oscillations of high amplitude alternating with periods of pulses of low amplitude. In two cases, the high-frequency oscillatory pattern with low amplitude was found around low mean levels of 22.8 and 25.7 IU/L. The LH oscillatory pattern also had a high frequency, but at a lower level, giving a high FSH/LH ratio. The coincidence index of FSH with LH peaks was 76.6%. We concluded that at menopause, the frequency of FSH and LH secretion increases with a high FSH/LH ratio. Obese menopausal women may have the same high-frequency oscillatory patterns, but at low levels.

Novel analytical approach to monitoring advanced glycosylation end products in human serum with on-line spectrophotometric and spectrofluorometric detection in a flow system

We proposed a simple analytical procedure for measurement of serum advanced glycosylation end products (AGEs) based on simultaneous detection of low-molecular-mass peptides and AGEs with a flow system and two detectors connected on-line: spectrophotometric for peptides (lambda = 280 nm) and spectrofluorometric for AGEs (lambda ex = 247 nm, lambda em = 440 nm). Sample pretreatment was carried out in microcentrifuge tubes: Serum (20 microL) was deproteinized with trichloroacetic acid (480 microL, 0.15 mol/L) and lipids were extracted with chloroform (100 microL). Twenty microliters of the filtered aqueous layer was injected to the flow system and the relation between fluorescence and absorption signals was measured. A peptide-derived AGE calibrator was used for calibration. Within-day and between-day CVs were 6.7% and 9.1%, respectively, at an AGE concentration corresponding approximately to that in healthy individuals. Mean results (+/-SD) in 10 healthy individuals were 10.1% +/- 1.0%, in 21 patients with diabetes without complications 18.0% +/- 6.2%, in 25 patients with complications 24.1% +/- 15.4%, and in 12 diabetic patients in end-stage renal disease 92% +/- 30%. Comparison with an ELISA procedure (x, in arbitrary units/L) yields a regression equation y = 0.713x + 1.24 (Sy [symbol: see text] x = 6777, r = 0.8477, n = 41).

Menopause in normal and uncomplicated NIDDM women: physical and emotional symptoms and hormone profile

OBJECTIVE

To compare the physical characteristics, emotional symptoms and metabolic conditions of menopausal women with and without non insulin dependent diabetes mellitus (NIDDM).

METHODS

We studied 100 menopausal women 45-72 years of age, 51 with and 49 without NIDDM, in a cross-sectional design. Biological characteristics were collected and emotional symptoms were assessed with a modified Hamilton and Bech-Rafaelsen scale, scoring depression, anxiety, non specific symptoms of depression (NSSD) and the empty nest syndrome (ENS). Weight, body mass index (BMI), waist/hip and abdomen/hip ratios and percent of body fat were registered. The sulfoconjugated form of the dehydroepiandrosterone (DHEAS), follicle stimulating hormone (FSH), cortisol and fasting, as well as postprandial insulin/glucose ratios, were measured in blood.

RESULTS

Women with NIDDM had earlier mean age for menopause, more central obesity and less peripheral fat; they had also more prevalent emotional symptoms than non diabetic menopausal women. In women with NIDDM, symptoms were associated with years since diagnosis and with BMI. In non diabetic menopausal women schooling and attitudes to sexuality were associated with symptoms. FSH was inversely associated with BMI in both diabetic and non diabetic women; postprandial insulin/glucose ratio was correlated with central obesity in the group without NIDDM and cortisol with sitting systolic blood pressure (SBP) in the group with NIDDM.

CONCLUSION

The diagnosis of NIDDM and its metabolic conditions were associated with an increased frequency of some symptoms in menopausal women.

Novel analytical approach to monitoring advanced glycosylation end products in human serum with on-line spectrophotometric and spectrofluorometric detection in a flow system

We proposed a simple analytical procedure for measurement of serum advanced glycosylation end products (AGEs) based on simultaneous detection of low-molecular-mass peptides and AGEs with a flow system and two detectors connected on-line: spectrophotometric for peptides (λ = 280 nm) and spectrofluorometric for AGEs (λex = 247 nm, λem = 440 nm). Sample pretreatment was carried out in microcentrifuge tubes: Serum (20 μL) was deproteinized with trichloroacetic acid (480 μL, 0.15 mol/L) and lipids were extracted with chloroform (100 μL). Twenty microliters of the filtered aqueous layer was injected to the flow system and the relation between fluorescence and absorption signals was measured. A peptide-derived AGE calibrator was used for calibration. Within-day and between-day CVs were 6.7% and 9.1%, respectively, at an AGE concentration corresponding approximately to that in healthy individuals. Mean results (±SD) in 10 healthy individuals were 10.1% ± 1.0%, in 21 patients with diabetes without complications 18.0% ± 6.2%, in 25 patients with complications 24.1% ± 15.4%, and in 12 diabetic patients in end-stage renal disease 92% ± 30%. Comparison with an ELISA procedure (x, in arbitrary units/L) yields a regression equation y = 0.713x + 1.24 (Sy‖x = 6777, r = 0.8477, n = 41).

The effect of hormone replacement therapy on blood pressure and cardiovascular risk factors in menopausal women with moderate hypertension

OBJECTIVE

To assess the effect of injectable hormone replacement therapy (HRT) vs a placebo in hypertensive menopausal women.

DESIGN AND METHODS

Prospective randomised double-blind study over 90 days. Fifty-five menopausal women with mild to moderate hypertension, stopped their antihypertensive medication and were studied for 2 weeks. Diastolic BP increased to over 105 mm Hg in five patients who were not included in the study. The remaining patients were randomly allocated to three groups: placebo (PL), estradiol valeranate 10 mg (E), and estradiol valeranate 4 mg plus prasterone enantate 200 mg (E+P). A further five patients were excluded from the study for different reasons.

RESULTS

Standing and recumbent BP decreased in the PL group but did not change in the E and E+P patients. No change was observed in the serum levels of total cholesterol or low density lipoprotein (LDL)-cholesterol at the end of the trial. Plasma renin activity (PRA), aldosterone and insulin levels decreased during the study; PRA fell more significantly in the E+P group, the aldosterone reduction was highly significant in both hormone treated groups, specially the E+P group. Plasma insulin decreased in all groups and FSH levels were lower in the two treatment groups.

CONCLUSIONS

In a randomised controlled trial no rise in BP was found after 90 days in hypertensive women with two forms of HRT. There was an unexpected fall in BP in those women allocated to placebo injections.

[The evaluation of medical research]

The peer review process for manuscripts submitted for publication to scientific journals and for the evaluation of grant research proposals is unsatisfactory in several respects. We examine here some of the problems related with evaluation of scientific merit. Some criteria for rejection are proposed, i.e. a poor preparation of the manuscript, a lack of a distinct hypothesis, a disagreement between hypothesis and methodology, and a deficient methodology. Other important criteria causes of rejection would be lack of originality of the hypothesis, scarce relevance of the work, and inconsistency in the results. Conversely, interesting work are rejected for invalid objections such as "less than optimal design", "lack of experience of the group" and some conceptual objections which are controversial. In order to improve the peer review process, we propose a larger role of editorial committees in final editorial decisions, an improved mechanism for selection of reviewers, and more explicit criteria for causes of rejection for reviewers and authors.