Dried mulberry fruit ameliorates cardiovascular and liver histopathological changes in high-fat diet-induced hyperlipidemic mice.

BACKGROUND AND AIM: Metabolic disease encompasses most contemporary non-communicable diseases, especially cardiovascular and fatty liver disease. Mulberry fruits of Morus alba L. are a favoured food and a traditional medicine. While they are anti-atherosclerotic and reduce hyperlipidemic risk factors, studies need wider scope that include ameliorating cardiovascular and liver pathologies if they are to become clinically effective treatments. Therefore, the present study sought to show that freshly dried mulberry fruits (dMF) might counteract the metabolic/cardiovascular pathologies in mice made hyperlipidemic by high-fat diet (HF). EXPERIMENTAL PROCEDURE: C57BL/6J mice were fed for 3 months with either: i) control diet, ii) HF, iii) HF+100 mg/kg dMF, or iv) HF+300 mg/kg dMF. Body weight gain, food intake, visceral fat accumulation, fasting blood glucose, plasma lipids, and aortic, heart, and liver histopathologies were evaluated. Adipocyte lipid accumulation, autophagy, and bile acid binding were also investigated. RESULTS AND CONCLUSION: HF increased food intake, body weight, visceral fat, plasma total cholesterol (TC) and low-density lipoprotein (LDL), TC/HDL ratio, blood glucose, aortic collagen, arterial and cardiac wall thickness, and liver lipid. Both dMF doses prevented hyperphagia, body weight gain, and visceral fat accumulation, lowered blood glucose, plasma TG and unfavourable TC/HDL and elevated plasma HDL beyond baseline. Arterial and cardiac wall hypertrophy, aortic collagen fibre accumulation and liver lipid deposition ameliorated in dMF-fed mice. Clinical trials on dMF are worthwhile but outcomes should be holistic commensurate with the constellation of disease risks. Here, dMF should supplement the switch to nutrient-rich from current energy-dense diets that are progressively crippling national health systems.

Control of ion transport in mouse proximal and distal colon by prolactin.

The lactogenic hormone prolactin (PRL) has been known to affect Ca(2+) and electrolyte transport in the intestinal epithelium. In the present study we analyzed ion transport in mouse proximal and distal colon, and acute changes induced by PRL. In the proximal colon, carbachol activated a Ca(2+) dependent Cl(-) secretion that was sensitive to DIDS and NFA. In the distal colon, both ATP and carbachol activated K(+) secretion. Ca(2+) -activated KCl transport in proximal and distal colon was inhibited by PRL (200 ng/ml), while amiloride sensitive Na(+) absorption and cAMP induced Cl(-) secretion remained unaffected. Luminal large conductance Ca(2+) -activated K(+) (BK) channels were largely responsible for Ca(2+) -activated K(+) secretion in the distal colon, and basolateral BK channels supported Ca(2+) -activated Cl(-) secretion in the proximal colon. Ca(2+) chelating by BAPTA-AM attenuated effects of carbachol and abolished effects of PRL. Both inhibition of PI3 kinase with wortmannin and blockage of MAP kinases with SB 203580 or U 0126, interfered with the acute inhibitory effect of PRL on ion transport, while blocking of Jak/Stat kinases with AG 490 was without effects. PRL attenuated the increase in intracellular Ca(2+) that was caused by stimulation of isolated colonic crypts with carbachol. Thus PRL inhibits Ca(2+) dependent Cl(-) and K(+) secretion by interfering with intracellular Ca(2+) signaling and probably by activating PI3 kinase and MAP kinase pathways.

Expression of voltage-gated potassium channels in human and mouse colonic carcinoma.

PURPOSE: Voltage-gated Kv potassium channels, like ether a go-go (EAG) channels, have been recognized for their oncogenic potential in breast cancer and other malignant tumors. EXPERIMENTAL DESIGN: We examined the molecular and functional expression of Kv channels in human colonic cancers and colon of mice treated with the chemical carcinogens dimethylhydrazine and N-methyl-N-nitrosourea. The data were compared with results from control mice and animals with chemically induced DSS colitis. RESULTS: Electrogenic salt transport by amiloride-sensitive Na+ channels and cyclic AMP-activated cystic fibrosis transmembrane conductance regulator Cl- channels were attenuated during tumor development and colitis, whereas Ca2+-dependent transport remained unchanged. Kv channels, in particular Eag-1, were enhanced during carcinogenesis. Multiplex reverse transcription-PCR showed increased mRNA expression for Kv1.3, Kv1.5, Kv3.1, and members of the Eag channel family, after dimethylhydrazine and N-methyl-N-nitrosourea treatment. Eag-1 protein was detected in the malignant mouse colon and human colonic cancers. Genomic amplification of Eag-1 was found in 3.4% of all human colorectal adenocarcinoma and was an independent marker of adverse prognosis. CONCLUSIONS: The study predicts an oncogenic role of Kv and Eag channels for the development of colonic cancer. These channels may represent an important target for a novel pharmacotherapy of colonic cancer.

High-calcium diet modulates effects of long-term prolactin exposure on the cortical bone calcium content in ovariectomized rats.

High physiological prolactin induced positive calcium balance by stimulating intestinal calcium absorption, reducing renal calcium excretion, and increasing bone calcium deposition in female rats. Although prolactin-induced increase in trabecular bone calcium deposition was absent after ovariectomy, its effects on cortical bones were still controversial. The present investigation, therefore, aimed to study the effect of in vivo long-term high physiological prolactin induced by either anterior pituitary (AP) transplantation or 2.5 mg/kg prolactin injection on cortical bones in ovariectomized rats. Since the presence of prolactin receptors (PRLR) in different bones of normal adult rats has not been reported, we first determined mRNA expression of both short- and long-form PRLRs at the cortical sites (tibia and femur) and trabecular sites (calvaria and vertebrae) by using the RT-PCR. Our results showed the mRNA expression of both PRLR isoforms with predominant long form at all sites. However, high prolactin levels induced by AP transplantation in normal rats did not have any effect on the femoral bone mineral density or bone mineral content. By using (45)Ca kinetic study, 2.5 mg/kg prolactin did not alter bone formation, bone resorption, calcium deposition, and total calcium content in tibia and femur of adult ovariectomized rats. AP transplantation also had no effect on the cortical total calcium content in adult ovariectomized rats. Because previous work showed that the effects of prolactin were age dependent and could be modulated by high-calcium diet, interactions between prolactin and these two parameters were investigated. The results demonstrated that 2.0% wt/wt high-calcium diet significantly increased the tibial total calcium content in 9-wk-old young AP-grafted ovariectomized rats but decreased the tibial total calcium content in 22-wk-old adult rats. As for the vertebrae, the total calcium contents in both young and adult rats were not changed by high-calcium diet. The present results thus indicated that the adult cortical bones were potentially direct targets of prolactin. Moreover, the effects of high physiological prolactin on cortical bones were age dependent and were observed only under the modulation of high-calcium diet condition.

An extract from the medicinal plant Phyllanthus acidus and its isolated compounds induce airway chloride secretion: A potential treatment for cystic fibrosis.

According to previous reports, flavonoids and nutraceuticals correct defective electrolyte transport in cystic fibrosis (CF) airways. Traditional medicinal plants from China and Thailand contain phytoflavonoids and other bioactive compounds. We examined herbal extracts of the common Thai medicinal euphorbiaceous plant Phyllanthus acidus for their potential effects on epithelial transport. Functional assays by Ussing chamber, patch-clamping, double-electrode voltage-clamp and Ca2+ imaging demonstrate activation of Cl- secretion and inhibition of Na+ absorption by P. acidus. No cytotoxic effects of P. acidus could be detected. Mucosal application of P. acidus to native mouse trachea suggested transient and steady-state activation of Cl- secretion by increasing both intracellular Ca2+ and cAMP. These effects were mimicked by a mix of the isolated components adenosine, kaempferol, and hypogallic acid. Additional experiments in human airway cells and CF transmembrane conductance regulator (CFTR)-expressing BHK cells and Xenopus laevis oocytes confirm the results obtained in native tissues. Cl- secretion was also induced in tracheas of CF mice homozygous for Phe508del-CFTR and in Phe508del-CFTR homozygous human airway epithelial cells. Taken together, P. acidus corrects defective electrolyte transport in CF airways by parallel mechanisms including 1) increasing the intracellular levels of second messengers cAMP and Ca2+, thereby activating Ca2+-dependent Cl- channels and residual CFTR-Cl- conductance; 2) stimulating basolateral K+ channels; 3) redistributing cellular localization of CFTR; 4) directly activating CFTR; and 5) inhibiting ENaC through activation of CFTR. These combinatorial effects on epithelial transport may provide a novel complementary nutraceutical treatment for the CF lung disease.

Enhanced trabecular-bone calcium deposition in female rats with a high physiological dose of prolactin diminishes after ovariectomy.

Although an increase in trabecular-bone calcium deposition has been shown to be regulated by prolactin during lactation, the physiological significance of prolactin in bone calcium metabolism in nonlactating rats remains unclear. This investigation sought to demonstrate the effects of endogenous prolactin and a high physiological dose of exogenous prolactin on bone turnover and bone calcium deposition in normal female rats, using the 45Ca-labeling technique. Our results showed that suppression of endogenous prolactin with 6 mg/kg bromocriptine for 15 days significantly enhanced bone formation, but not bone resorption, in primarily trabecular sites, resulting in a significant increase in calcium deposition in the sternum and vertebrae, from -0.20+/-0.07 to 0.40+/-0.09 (p<0.05) and -0.07+/-0.11 to 0.34+/-0.06 (p<0.05) mmol Ca.(g dry mass)-1, respectively. Similarly, 2.5 mg/kg prolactin, a high physiological dose, increased sternal and vertebral calcium deposition, from -0.20+/-0.07 to 0.24+/-0.09 (p<0.05) and -0.07+/-0.11 to 0.25+/-0.18 (p<0.05) mmol Ca.(g dry mass)-1, respectively, by increasing bone formation more than bone resorption. However, as expected, prolactin had no effect on the tibia or femur, which are primarily cortical sites. Because several actions of prolactin have been known to be estradiol-dependent, we further investigated the dependence of prolactin action on 17beta-estradiol. We found that 2.5 mg/kg prolactin did not increase sternal calcium deposition in ovariectomized rats. However, 10 microg/kg 17beta-estradiol supplementation restored the action of prolactin. Ovariectomized rats given 17beta-estradiol plus prolactin also manifested slightly but significantly higher sternal total calcium content than sham-operated rats, (4.58+/-0.12 vs. 4.36+/-0.11 mmol Ca.(g dry mass)-1 (p<0.05)). We concluded that a high physiological dose of prolactin promoted calcium deposition in primarily trabecular sites of nonlactating rats. This effect was diminished after ovariectomy. In addition, we showed that basal endogenous prolactin played a role in the maintenance of normal trabecular-bone turnover.