Heat shock protein production and immunity and altered fetal development in diabetic pregnant rats

Skeletal malformations and growth disturbances in fetuses of mild diabetic rats

Introducción.

En la actualidad, la diabetes mellitus representa una de las condiciones médicas que complica el embarazo con mayor frecuencia, lo que afecta el crecimiento y el desarrollo fetal.

Objetivo.

Determinar las malformaciones esqueléticas y alteraciones en el crecimiento en fetos de ratas Wistar diabéticas.

Materiales y métodos.

Se utilizó un modelo de diabetes moderada inducida neonatalmente con estreptozotocina (STZ 100 mg/kg de peso corporal, por vía subcutánea) en ratas Wistar. En la adultez, las ratas sanas y diabéticas se aparearon con machos sanos de la misma edad y cepa. El día 20 de gestación se practicó la cesárea bajo anestesia. Se extrajeron los fetos, se pesaron y clasificaron como pequeños (PAG), adecuados (AEG) o grandes (GEG) para la edad gestacional. Los fetos seleccionados se procesaron para el análisis de anomalías esqueléticas y sitios de osificación.

Resultados.

En la descendencia de las ratas diabéticas, hubo un mayor porcentaje de fetos clasificados como pequeños o grandes y un menor porcentaje de fetos con peso adecuado; el promedio de peso fetal fue menor y había menos sitios de osificación. Se observaron alteraciones en la osificación de cráneo, esternón, columna vertebral, costillas y extremidades anteriores y posteriores; y también, hubo una correlación directa entre el peso y el grado de osificación fetal.

Hubo malformaciones congénitas asociadas con la fusión y bifurcación de las costillas, así como cambios indicativos de hidrocefalia, como la forma de domo del cráneo, una amplia distancia entre los parietales y la anchura de las fontanelas anterior y posterior.

Conclusión.

La diabetes moderada durante la gestación altera el crecimiento y el desarrollo fetal, que se ve afectado tanto por macrosomía y la restricción del crecimiento intrauterino como por malformaciones esqueléticas.

Effects of snack intake during pregnancy and lactation on reproductive outcome in mild hyperglycemic rats

Metabolic disorders, like diabetes, as well as maternal diet, alter nutrient availability in utero, inducing adaptations in the offspring. Whether the effects of maternal hyperglycemia are modulated by diet, however, has yet to be explored. In the current study, we examined this issue by giving females rats, treated neonatally with STZ to induce mild hyperglycemia, and control littermates either ad libitum access to standard chow (Control n = 17; STZ n = 16) or standard chow and snacks (Control-snack n = 18; STZ-snack n = 19) (potato chips and a red fruit-flavored sucrose syrup solution 1.5%) throughout pregnancy and lactation. We hypothesized that the maternal glucose intolerance typically seen in female rats treated neonatally with STZ would be exacerbated by snack intake, and that the combination of snack intake and STZ treatment would lead to alterations in maternal behavior and offspring development. Maternal body weight and food intake were measured daily through pregnancy and lactation and litter weight throughout lactation. At birth, litter size, offspring weight, body length, and anogenital distance were obtained and offspring were classified according to their weight. Measures of nursing and retrieval behavior, as well as exploration in the open field and the elevated plus-maze were also recorded. As predicted, snack intake tended to aggravate the glucose intolerance of STZ-treated rats during pregnancy. Both Control and STZ-treated females that had access to snacks ate more calories and fat, but less carbohydrate and protein than females having access to chow alone. Overall, STZ-treated dams gave birth to fewer pups. Chow-fed STZ females gave birth to a greater proportion of large for pregnancy age pups, whereas dams in the Control-snack group gave birth to a greater proportion of small pups. The birth weight classification of pups born to STZ-snack rats, however, resembled that of the Control chow-fed females. Although all litters gained weight during lactation, litters from snack-fed dams gained less weight regardless of maternal hyperglycemia and did not show catch-up growth by weaning. Overall, STZ rats spent more time nest building, whereas the average inter milk ejection interval was higher in snack-fed females. STZ-snack dams retrieved the complete litter faster than dams in the other groups. Together, these data suggest that when mild hyperglycemic females are given access to snacks throughout pregnancy and lactation their intake is similar to that of Control females given snack access. The combination of hyperglycemia and snack access tended to decrease glucose tolerance in pregnancy, and normalized birth weight classification, but produced few other effects that were not seen as a function of snack intake or hyperglycemia alone. Since birth weight is a strong predictor of health issues, future studies will further investigate offspring behavioral and metabolic outcomes later in life.

Study protocol to investigate biomolecular muscle profile as predictors of long-term urinary incontinence in women with gestational diabetes mellitus

BACKGROUND

Pelvic floor muscles (PFM) and rectus abdominis muscles (RAM) of pregnant diabetic rats exhibit atrophy, co-localization of fast and slow fibers and an increased collagen type I/III ratio. However, the role of similar PFM or RAM hyperglycemic-related myopathy in women with gestational diabetes mellitus (GDM) remains poorly investigated. This study aims to assess the frequency of pelvic floor muscle disorders and pregnancy-specific urinary incontinence (PS-UI) 12 months after the Cesarean (C) section in women with GDM. Specifically, differences in PFM/RAM hyperglycemic myopathy will be evaluated.

METHODS

The Diamater is an ongoing cohort study of four groups of 59 pregnant women each from the Perinatal Diabetes Research Centre (PDRC), Botucatu Medical School (FMB)-UNESP (São Paulo State University), Brazil. Diagnosis of GDM and PS-UI will be made at 24-26 weeks, with a follow-up at 34-38 weeks of gestation. Inclusion in the study will occur at the time of C-section, and patients will be followed at 24-48 h, 6 weeks and 6 and 12 months postpartum. Study groups will be classified as (1) GDM plus PS-UI; (2) GDM without PS-UI; (3) Non-GDM plus PS-UI; and (4) Non-GDM without PS-UI. We will analyze relationships between GDM, PS-UI and hyperglycemic myopathy at 12 months after C-section. The mediator variables to be evaluated include digital palpation, vaginal squeeze pressure, 3D pelvic floor ultrasound, and 3D RAM ultrasound. RAM samples obtained during C-section will be analyzed for ex-vivo contractility, morphological, molecular and OMICS profiles to further characterize the hyperglycemic myopathy. Additional variables to be evaluated include maternal age, socioeconomic status, educational level, ethnicity, body mass index, weight gain during pregnancy, quality of glycemic control and insulin therapy.

DISCUSSION

To our knowledge, this will be the first study to provide data on the prevalence of PS-UI and RAM and PFM physical and biomolecular muscle profiles after C-section in mothers with GDM. The longitudinal design allows for the assessment of cause-effect relationships between GDM, PS-UI, and PFMs and RAMs myopathy. The findings may reveal previously undetermined consequences of GDM.

Experimental diabetes impairs maternal reproductive performance in pregnant Wistar rats and their offspring

The aim of this study was to determine the effect of mild hyperglycemia on metabolism during pregnancy, the maternal reproductive performance, and the characteristics of the offspring in neonatal mild diabetic-induced Wistar rats. The experimental diabetes model was generated by neonatal streptozotocin administration (100 mg of streptozotocin/Kg bw/sc) in female Wistar rats. At adulthood, the control and diabetic group were mated. At the 20th day of gestation, a maternal and fetal blood sample were collected for biochemical measurement. The maternal livers, fetal livers, and placenta were removed for oxidative stress measurements. Maternal reproductive outcomes and fetal and placental morphometric measurements were analyzed. The fetuses were classified as small, appropriate, and large for pregnancy age, and examined for the presence of external anomalies. The diabetic group showed mild hyperglycemia, altered glucose tolerance, increased total cholesterol, triglycerides, and hemoglobin A1c during pregnancy. At the 20th day of gestation the diabetic mothers presented increased reabsorptions and embryonic losses before and after implantation, reduced corpora lutea number, litter size, implantation sites, live fetuses, and decreased efficiency of implantation rate. Similarly, the offspring showed reduced fetal, craniofacial, and placental dimensions, in addition to a higher proportion of small fetuses for pregnancy age. Mild hyperglycemia during pregnancy did not generate marked oxidative stress in the mother, and in fetal liver and placenta decreased antioxidant activity was evident by significant consumption of reduced glutathione. Mild diabetes led to a negative impact on maternal reproductive performance and characteristics of the offspring. This experimental model reproduced maternal and fetal outcomes of pregnant rats presenting controlled diabetes.

ABBREVIATIONS

bw: body weight; sc: subcutaneous; DM: diabetes mellitus; STZ: streptozotocin; OGTT: oral glucose tolerance test; ITT: insulin tolerance test; GSH: glutathione; MDA: malondialdehyde; AOPPs: advanced oxidation protein products; TBARs: thiobarbituric acid reaction; SPA: small for pregancy age; APA: appropriate for pregnancy age; LPG: large for pregnancy age; ROS: reactive oxygen species.

[Effect of heat exposure in the second trimester of pregnancy on intrauterine growth of fatal rat and the expression of HSP70, Bax and Bcl-2 of placenta]

OBJECTIVE

To investigate the effect of heat exposure during the second week of pregnancy on placental development and intrauterine growth of fetal rats.

METHODS

24 pregnant rats were either exposed or not to a temperature of 35∓1 degrees celsius; during the second week of pregnancy. The body weight gain of the pregnant rats was measured regularly, and in late pregnancy, the pregnant rats were dissected and the number, weight, length, tail length, appearance of the offspring rats, number of live and still births, and the placental weight were recorded. The expressions of HSP70, Bax and Bcl-2 in the placenta were determined.

RESULTS

Compared with the control group, the pregnant rats in heat exposure group had significantly lower body weight at the end of pregnancy and gestational weight gain, and the body weight, body length and tail length of the offspring rats were also significantly lower or smaller (P<0.05). The placental weight was comparable between the two groups. The placental expressions of HSP70,Bax,and Bcl-2 were significantly higher in the heat exposure group than in the control group (P<0.05).

CONCLUSION

Heat exposure during the second trimester of pregnancy has adverse effects on placental development and intrauterine growth of the fetal rats by inducing heat shock response of placental tissue and apoptosis of the placental cells.

Physiological and biochemical measurements before, during and after pregnancy of healthy rats

PURPOSE

To analyze the physiological and biochemical measurements before, during and after pregnancy of healthy rats.

METHODS

Wistar adult females rats (n=8) were weighed and blood samples were obtained before, during and after pregnancy for biochemical determinations, chow intake, water consumption and milk production were evaluated. At day 10 postpartum, the rats were killed for weighing of organs and adipose tissues.

RESULTS

The results showed increase in body weight, serum insulin and ingestion of water and chow. At day 17 pregnancy, presented normal values in the OGTT. At days 7, 14 and 20 of pregnancy, there was increase in triglyceride levels. At term pregnancy, there was weight gain due to fetal growth. In the postpartum period presented reduced blood glucose levels. The glycemic means were reduced during and after pregnancy compared to after pregnancy. The triglyceride concentrations were increased before and during pregnancy in relation to after pregnancy. The total cholesterol levels presented no changes.

CONCLUSION

The use of experimental animals is suitable for evaluation of metabolic changes because the profile of answers found in this study was similar to human profile, showing the relevance of translational research to better understand the pathophysiological mechanisms and possible treatment for diseases.

Hsp70 plays an important role in high-fat diet induced gestational hyperglycemia in mice

Gestational diabetes mellitus (GDM) has emerged as an epidemic disease during the last decade, affecting about 2 to 5% pregnant women. Even among women who have gestational hyperglycemia may also be positively related to adverse outcomes as GDM. Since heat shock protein (Hsp) 70 has been reported to be associated with diabetes and insulin resistance and its expression was reported to be negatively regulated by the membrane-permeable Hsp70 inhibitor MAL3-101 while positively regulated by the Hsp70 activator BGP-15, we investigated whether Hsp70 played a role in a gestational hyperglycemia mouse model. Mice were divided into non-pregnant and pregnant groups, and each comprised three subgroups: control, high-fat diet (HFD) + MAL3-101, and HFD + BGP-15. We examined the serum levels of triglycerides, total cholesterol, glucose, and insulin, as well as conducted thermal detection of brown adipose tissue (BAT). The role of Hsp70 in BAT apoptosis was also investigated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and caspase-3 staining. Higher serum level of Hsp70 was associated with increased bodyweight gain after pregnancy in mice fed HFD. Circulating Hsp70 was elevated in control pregnant mice compared to control non-pregnant mice. BGP-induced serum Hsp70 expression reduced triglycerides, total cholesterol, glucose, and insulin levels in the serum. Additionally, thermal detection of BAT, TUNEL, and caspase-3 staining revealed relationship correlation between Hsp70 and BAT functions. Hsp70 level is associated with hyperglycemia during pregnancy. Our results support the role of Hsp70 in facilitating BAT activities and protecting BAT cells from apoptosis via caspase-3 pathway.

Extracellular HSP70 levels in diabetic environment in rats

The expression of HSP70 in embryonic cells of mammals and its role for their normal development and protection is an important aspect to be investigated in pregnancy and/or mild diabetes. In this sense, the present study evaluated the effects of mild diabetes on maternal reproductive parameters and HSP70 levels in Wistar rats at different stages of life and in their offspring. Mild diabetes was induced by a beta-cytotoxic drug (streptozotocin) at birth. Four experimental groups were evaluated: at 90 days of age: nonpregnant nondiabetic (ND90) and nonpregnant mild diabetic (D90) female rats, and at term pregnancy: pregnant female rats of both glycemic status were examined (NDP and DP, respectively). The rats were submitted to oral glucose tolerance test, and blood samples were collected for determination of HSP70 levels. In addition, the reproductive performance of pregnant rats was assessed and HSP70 levels determined in their offspring blood samples. The HSP70 levels and maternal reproductive performance presented no difference between ND and D rats, regardless of the life stage. The HSP70 levels were increased in D90 rats and lower in offspring from D rats. Maternal HSP70 levels were positively correlated to the number of dead embryos. In conclusion, mild diabetes did not affect maternal reproductive performance, but high maternal HSP70 levels compromised embryo development. In addition, offspring from D rats exhibited lower HSP70 levels, showing that this protein can be used as an indicator of metabolic consequences of diabetes and predictor of related disorders in adulthood.

Increased circulating heat shock protein 70 (HSPA1A) levels in gestational diabetes mellitus: a pilot study

Recent data indicate that serum Hsp70 (HSPA1A) levels are increased in type 1 and 2 diabetes mellitus. However, there is no report in the literature on circulating Hsp70 levels in gestational diabetes mellitus. In this pilot study, we measured serum Hsp70 levels in 11 pregnant women with pregestational diabetes, 38 women with gestational diabetes, and 40 healthy pregnant women with ELISA. Plasma glucose levels, serum insulin concentrations, HbA1c values, and the Homeostatic Model Assessment-Insulin Resistance (HOMA-IR) index were also determined. According to our results, serum Hsp70 concentrations were significantly higher in women with pregestational and gestational diabetes mellitus than in healthy pregnant women. In addition, pregestational diabetic women had significantly higher Hsp70 levels than those with gestational diabetes. Furthermore, in the group of women with gestational diabetes mellitus, serum Hsp70 levels showed a significant positive correlation with HbA1c values. However, there was no other relationship between clinical features and metabolic parameters of the study subjects and their serum Hsp70 levels in either study group. In conclusion, we demonstrated for the first time in the literature that serum Hsp70 levels are increased and correlate with HbA1c values in women with gestational diabetes mellitus. Nevertheless, further studies are needed to determine whether circulating Hsp70 plays a causative role in the pathogenesis of gestational diabetes or elevated serum Hsp70 levels are only consequences of the disease.

Streptozotocin-induced diabetes models: pathophysiological mechanisms and fetal outcomes

Glucose homeostasis is controlled by endocrine pancreatic cells, and any pancreatic disturbance can result in diabetes. Because 8% to 12% of diabetic pregnant women present with malformed fetuses, there is great interest in understanding the etiology, pathophysiological mechanisms, and treatment of gestational diabetes. Hyperglycemia enhances the production of reactive oxygen species, leading to oxidative stress, which is involved in diabetic teratogenesis. It has also been suggested that maternal diabetes alters embryonic gene expression, which might cause malformations. Due to ethical issues involving human studies that sometimes have invasive aspects and the multiplicity of uncontrolled variables that can alter the uterine environment during clinical studies, it is necessary to use animal models to better understand diabetic pathophysiology. This review aimed to gather information about pathophysiological mechanisms and fetal outcomes in streptozotocin-induced diabetic rats. To understand the pathophysiological mechanisms and factors involved in diabetes, the use of pancreatic regeneration studies is increasing in an attempt to understand the behavior of pancreatic beta cells. In addition, these studies suggest a new preventive concept as a treatment basis for diabetes, introducing therapeutic efforts to minimize or prevent diabetes-induced oxidative stress, DNA damage, and teratogenesis.

Gestational exposure to Byrsonima verbascifolia: teratogenicity, mutagenicity and immunomodulation evaluation in female Swiss mice

ETHNOPHARMACOLOGICAL RELEVANCE

Byrsonima verbascifolia is used in folk medicine to treat diarrhea, intestinal infections, chronic wounds, Chagas disease, inflammation and as a diuretic. However there is no investigation regarding the Byrsonima verbascifolia hydrometanolic extract (BVHME) used during gestation.

MATERIALS AND METHODS

The pregnant females were randomly divided into 5 groups. Control group received saline plus DMSO (1%) in a volume of 0.1 mL/10 g (b.w.), via gavage, for at least 15 days prior to mating and throughout the gestational period. The Pre-treatment group received the BVHME, via gavage, at a dose of 50 mg/kg (b.w.) for at least 15 days prior to mating and up to the appearance of the vaginal plug. The Organogenesis group received the BVHME at a dose of 50 mg/kg (b.w.), via gavage, on the 5-15th gestational day. The Gestational group received the BVHME at a dose of 50 mg/kg (b.w.), via gavage, throughout the gestational period (from the 1st to the 18th day of pregnancy). The Pre+Gestational group received the BVHME at a dose of 50mg/kg (b.w.), via gavage, for at least 15 days prior to mating and up to throughout the gestational period. The clinical signals of maternal and fetuses toxicity were evaluated, as the mutagenicity and immunomodulation tests were performed.

RESULTS AND CONCLUSIONS

The present investigation shows, for the first time, that the use of Byrsonima verbascifolia extract in pregnant Swiss mice, did not alter the female reproductive function, mutagenicity or immunostimulation as well as not interfere with embryofetal development at least in our experimental conditions.

Increased expression of heat shock protein 70 in chronic obstructive pulmonary disease

BACKGROUND

Heat shock protein 70 (HSP70) plays a critical role in the process of inflammation and innate immunity response under environmental stress.

OBJECTIVES

This study was to investigate HSP70 expression in the peripheral lung tissues of chronic obstructive pulmonary disease (COPD) patients and in human bronchial epithelial cells (16-HBE) exposed to cigarette smoke extract (CSE).

METHODS

Peripheral lung tissues were collected after lung cancer resection from 26 patients without COPD, 20 with mild COPD and 15 with advanced COPD, classified by lung function criteria. Among these cases, 37 were smokers and 24 non-smokers. Lung tissues were examined for histopathological changes and levels of HSP70 and IL-8. Cultured 16-HBE cells were stimulated with CSE in the absence or presence of HSP70 neutralizing antibody and the expressions of IL-8 and phospho-EGFR protein were determined.

RESULTS

Compared to patients without COPD, the levels of HSP70 and IL-8 were significantly increased in the lung tissues of COPD patients and positively correlated with the severity of the disease. The HSP70 expression was significantly higher in current smokers than that in non-smokers. Moreover, CSE-induced HSP70 significantly enhanced IL-8 production and EGFR phosphorylation in 16-HBE cells. The increases in IL-8 and phospho-EGFR were blocked by anti-HSP70 antibody.

CONCLUSIONS

Our study clarified that increased expression of HSP70 is closely related to COPD disease severity and smoking status. Extracellular HSP70 regulated chemokine productions and EGFR phosphorylation and plays an important role in the CSE-induced inflammatory and innate immunity responses in bronchial epithelia cells.

Neonatally induced mild diabetes: influence on development, behavior and reproductive function of female Wistar rats

BACKGROUND

Neonatal STZ treatment induces a state of mild hyperglycemia in adult rats that disrupts metabolism and maternal/fetal interactions. The aim of this study was investigate the effect of neonatal STZ treatment on the physical development, behavior, and reproductive function of female Wistar rats from infancy to adulthood.

METHODS

At birth, litters were assigned either to a Control (subcutaneous (s.c.) citrate buffer, n = 10) or STZ group, (streptozotocin (STZ) - 100 mg/kg-sc, n = 6). Blood glucose levels were measured on postnatal days (PND) 35, 84 and 120. In Experiment 1 body weight, length and the appearance of developmental milestones such as eye and vaginal opening were monitored. To assess the relative contribution of the initial and long term effects of STZ treatment this group was subdivided based on blood glucose levels recorded on PND 120: STZ hyperglycemic (between 120 and 300 mg/dl) and STZ normoglycemic (under 120 mg/dl). Behavioral activity was assessed in an open field on PND 21 and 75. In Experiment 2 estrous cyclicity, sexual behavior and circulating gonadotropin, ovarian steroid, and insulin levels were compared between control and STZ-hyperglycemic rats. In all measures the litter was the experimental unit. Parametric data were analyzed using one-way or, where appropriate, two-way ANOVA and significant effects were investigated using Tukey's post hoc test. Fisher's exact test was employed when data did not satisfy the assumption of normality e.g. presence of urine and fecal boli on the open field between groups. Statistical significance was set at p < 0.05 for all data.

RESULTS

As expected neonatal STZ treatment caused hyperglycemia and hypoinsulinemia in adulthood. STZ-treated pups also showed a temporary reduction in growth rate that probably reflected the early loss of circulating insulin. Hyperglycemic rats also exhibited a reduction in locomotor and exploratory behavior in the open field. Mild hyperglycemia did not impair gonadotropin levels or estrous cylicity but ovarian steroid concentrations were altered.

CONCLUSIONS

In female Wistar rats, neonatal STZ treatment impairs growth in infancy and results in mild hyperglycemia/hypoinsulinemia in adulthood that is associated with changes in the response to a novel environment and altered ovarian steroid hormone levels.

Induction of the 72 kDa heat shock protein by glucose ingestion in black pregnant women

Obese Black women are at increased risk for development of gestational diabetes mellitus and have worse perinatal outcomes than do obese women of other ethnicities. Since hsp72 has been associated with the regulation of obesity-induced insulin resistance, we evaluated associations between glucose ingestion, hsp72 release and insulin production in Black pregnant women. Specifically, the effect of a 50-g glucose challenge test (GCT) on heat shock protein and insulin levels in the circulation 1 h later was evaluated. Hsp27 and hsp60 levels remained unchanged. In contrast, serum levels of hsp72 markedly increased after glucose ingestion (p = 0.0054). Further analysis revealed that this increase was limited to women who were not obese (body mass index <30). Insulin levels pre-GCT were positively correlated with body mass index (p = 0.0189). Median insulin concentrations also increased post GCT in non-obese women but remained almost unchanged in obese women. Post-GCT serum hsp72 concentrations were inversely correlated with post GCT insulin concentrations (p = 0.0111). These observations suggest that glucose intake during gestation in Black women rapidly leads to an elevation in circulating hsp72 only in non-obese Black women. The release of hsp72 may regulate the extent of insulin production in response to a glucose challenge and, thereby, protect the mother and/or fetus from development of hyperglycemia, hyperinsulinemia, and/or immune system alterations.