Overfeeding During Lactation in Rats is Associated with Cardiovascular Insulin Resistance in the Short-Term.

Childhood obesity is associated with metabolic and cardiovascular comorbidities. The development of these alterations may have its origin in early life stages such as the lactation period through metabolic programming. Insulin resistance is a common complication in obese patients and may be responsible for the cardiovascular alterations associated with this condition. This study analyzed the development of cardiovascular insulin resistance in a rat model of childhood overweight induced by overfeeding during the lactation period. On birth day, litters were divided into twelve (L12) or three pups per mother (L3). Overfed rats showed a lower increase in myocardial contractility in response to insulin perfusion and a reduced insulin-induced vasodilation, suggesting a state of cardiovascular insulin resistance. Vascular insulin resistance was due to decreased activation of phosphoinositide 3-kinase (PI3K)/Akt pathway, whereas cardiac insulin resistance was associated with mitogen-activated protein kinase (MAPK) hyperactivity. Early overfeeding was also associated with a proinflammatory and pro-oxidant state; endothelial dysfunction; decreased release of nitrites and nitrates; and decreased gene expression of insulin receptor (IR), glucose transporter-4 (GLUT-4), and endothelial nitric oxide synthase (eNOS) in response to insulin. In conclusion, overweight induced by lactational overnutrition in rat pups is associated with cardiovascular insulin resistance that could be related to the cardiovascular alterations associated with this condition.

Loss of Nm23 is associated with a more favorable tumor microenvironment in patients with breast cancer.

AIM: Nm23 is a metastasis suppressor gene whose downregulation triggers metastatic progression. The aim of this study was to investigate the expression of Nm23 in breast carcinomas and its relationship with tumor microenvironment markers. METHODS: A retrospective study was done (128 breast cancer patients from 2007 to 2010). Nm23, LPA1, SMA, CD34, CD8, and CD68 protein expressions were evaluated using immunohistochemistry. Image analysis was used to determine the immunostaining percentage area of Nm23, LPA1, and SMA; the number of the total vessel fraction CD34 positive; and the number of CD8+ and CD68+ cells. The mean ± SE was calculated. The differences among groups were evaluated using Student t-test for parametric data and Mann Whitney U test for nonparametric data. RESULTS: Cases were divided into two groups: Nm23+ and Nm23-. LPA1 immunostaining was significantly increased in Nm23- group. Immunostaining percentage area of SMA was not significantly higher when Nm23 was negative. CD34 immunopositive blood vessels, number of T CD8+ cells, and the number of macrophage CD68+ cells were increased when Nm23 was absent. CONCLUSION: Our results suggest that the absence of Nm23 causes an increase in LPA1, CD8+ and CD68+ inflammatory cells, and angiogenesis marker. Therefore, Nm23 loss could be associated with a more favorable environment for the development and dissemination of breast cancer. However, more studies are needed to determine this association.

Expression of lysophosphatidic acid receptor 1 and relation with cell proliferation, apoptosis, and angiogenesis on preneoplastic changes induced by cadmium chloride in the rat ventral prostate.

BACKGROUND: Lysophosphatidic acid (LPA) is a phospholipid growth factor involved in cell proliferation, differentiation, migration, inflammation, angiogenesis, wound healing, cancer invasion, and survival. This study was directed to evaluate the immunoexpression of LPA-1, cell proliferation, apoptosis, and angiogenesis markers in preneoplastic lesions induced with cadmium chloride in rat prostate. METHODS: The following parameters were calculated in ventral prostate of normal rats and rats that received Cd in drinking water during 24 months: percentages of cells immunoreactive to LPA-1 (LILPA1), PCNA (LIPCNA), MCM7 (LIMCM7), ubiquitin (LIUBI), apoptotic cells (LIAPO), and p53 (LIp53); volume fraction of Bcl-2 (VFBcl-2); and length of microvessels per unit of volume (LVMV/mm3). Data were analyzed using Student's t-test and Pearson correlation test. RESULTS: The LILPA1 in dysplastic lesions and normal epithelium of Cd-treated rats was significantly higher than those in the control group. Markers of proliferation were significantly increased in dysplastic lesions, whereas some apoptotic markers were significantly decreased. No significant differences between groups were found in VFBcl-2. Dysplastic lesions showed a significant increase of LIp53. The length of microvessels per unit of volume was elevated in dysplastic acini. Statistically significant correlations were found only between LILPA1 and LIUBI. CONCLUSIONS: Our results suggest that LPA-1 might be implicated in dysplastic lesions induced by cadmium chloride development. More studies are needed to confirm its potential contribution to the disease.

Immunohistochemical study of cell proliferation, Bcl-2, p53, and caspase-3 expression on preneoplastic changes induced by cadmium and zinc chloride in the ventral rat prostate.

This work was directed to evaluate immunoexpression of markers for apoptosis, resistance to apoptosis, and cell proliferation, as well as estimates of nuclear size in ventral prostate of rats treated with cadmium chloride and cadmium+zinc chloride because a possible protective effect of zinc has been postulated. The following variables were studied: volume fraction (VF) of Bcl-2 immunostaining, percentage of cells immunoreactive to proliferating cell nuclear antigen (LIPCNA) and p53 (LIp53), numerical density of caspase-3 immunoreactive cells (NV caspase-3), and estimates of volume-weighted mean nuclear volume (upsilonV). The LIPCNA and VF of Bcl-2 were significantly increased in the treated animals. The dysplasias (independent of their origin) showed a significant increase of the LIp53, NV caspase-3, and upsilonV in comparison with normal acini from treated and control animals. It can be concluded that cell proliferation is enhanced in long-term cadmium-exposed rats, and exposure to zinc combined with cadmium had no effect on any of the variables studied when comparing with normal acini. The increase of nuclear upsilonV could indicate a more aggressive behavior for pretumoral lesions.

Stereological quantification of nerve fibers immunoreactive to PGP 9.5, NPY, and VIP in rat prostate during postnatal development.

This work was undertaken to study prostate innervation during the postnatal development of rats. It deals with the quantification of nervous fibers throughout all the regions of the rat prostate during the postnatal development using a general marker for nervous tissue, protein gene product 9.5, and 2 neuropeptides (NPY and VIP). Forty male Wistar rats (prepubertals, pubertals, young, and aged adults) were studied for immunohistochemistry of protein gene product (PGP 9.5), neuropeptide Y (NPY), and vasoactive intestinal polypeptide (VIP). They were also evaluated for length density of nerve fibers (L(V) PGP 9.5, L(V) NPY, L(V) VIP). Nerve fibers immunoreactive to the 3 antigens studied were detected in all the groups and in all the prostate zones. Periductal L(V) NPY evidenced a significant increase in the pubertal group, maintained throughout adult life. Periductal L(V) VIP showed a significant increase in young adults. The length densities of VIP and NPY fibers were significantly higher in periductal and ampular locations in comparison with dorsal and ventral sites. It can be concluded that the relative amount of nerve fibers in rat prostate, detected by PGP 9.5, does not change during postnatal development. There were significant changes in NPY and VIP fibers, showing an increase in periurethral ducts at puberty. The abundance of peptidergic innervation around the excretory ducts is related to their contractility. The development of innervation of periurethral ducts is regulated by androgens.

Quantitative and immunohistochemical evaluation of PCNA, androgen receptors, apoptosis, and Glutathione-S-Transferase P1 on preneoplastic changes induced by cadmium and zinc chloride in the rat ventral prostate.

BACKGROUND: This study was directed to evaluate the immunoexpression of markers for cell proliferation, apoptosis, nuclear androgen receptors, and Glutathione-S-Transferase P1 (GSTP1), in preneoplastic changes induced by cadmium chloride (Cd) and cadmium plus zinc chloride (Cd + Zn) in rat prostate. METHODS: The following parameters were calculated in ventral prostate of normal rats and rats that received Cd or Cd + Zn in drinking water during 24 months: numerical densities of columnar, basal, and GSTP1 immunoreactive epithelial cells; percentages of cells immunoreactive to: PCNA, (LI(PCNA)), androgen receptors (LI(AR)), and of apoptotic cells. RESULTS: The LI(PCNA) was significantly increased in the animals exposed to Cd + Zn, whereas the numerical densities of both columnar (N(V) columnar cells), and GSTP1 immunoreactive (N(V) GSTP1+) cells were significantly increased in the animals treated with metals in comparison with the controls. No significant differences between the two sources of dysplasias (Cd and Cd + Zn) respecting to LI(PCNA), N(V) columnar cells, and N(V) GSTP1+ were observed. The two types of dysplasias considered together showed a significant increase for the N(V) basal, N(V) columnar, and N(V) GSTP1+ cells in comparison with normal acini of treated and controls. The percentage of apoptotic nuclei did not show significant differences among the three groups studied. CONCLUSIONS: (1) The zinc has little influence in the development of the dysplastic changes of the rat prostate mediated by cadmium. (2) The decrease of apoptosis has little influence in the development of dysplasia. (3) GSTP1 could play a role in the response to the oxidative stress in the dysplastic changes caused by cadmium.

Presence of neuroendocrine cells during postnatal development in rat prostate: Immunohistochemical, molecular, and quantitative study.

BACKGROUND: This work was undertaken to study the prostate neuroendocrine cells (PNEC) during the post-natal development of rats. METHODS: Forty male Wistar rats (pre-pubertals, pubertals, young, and aged adults) were used for immunohistochemistry of chromogranin A (cgA), serotonin (SER), and protein gene product 9.5 (PGP9.5). They were also evaluated for numerical cell density (NV SER) and PNEC number per prostate (N SER). Five additional young adult rats were used for a RT-PCR study (mRNA cgA detection). RESULTS: Weak immunoreactivity to cgA was observed in pubertal rats. No PNEC immunostained to PGP 9.5 was observed. Cells expressing SER were detected in all the groups exclusively located in periurethral ducts. The NV SER increased significantly in pubertal animals. In aged animals, it decreased to levels observed in pre-pubertal rats. The N SER increased significantly from pre-pubertal to young adults, decreasing in aged adults. There was weak production of cgA mRNA, with more expression in the dorsal prostate. CONCLUSIONS: PNEC differ in rats when compared to humans: they are weakly immunopositive to cgA, do not express PGP 9.5, only show immunoreactivity to SER, and do not appear in acini. The changes in the amount of rat PNEC during the post-natal development suggest an androgenic influx. PNEC might regulate the contractility of periurethral ducts.