Effects of prenatal low protein and postnatal high fat diets on visceral adipose tissue macrophage phenotypes and IL-6 expression in Sprague Dawley rat offspring.

Adipose tissue macrophages (ATM) are implicated in adipose tissue inflammation and obesity-related insulin resistance. Maternal low protein models result in fetal programming of obesity. The study aims to answer whether maternal undernutrition by protein restriction affects the ATM M1 or M2 phenotype under postnatal high fat diet in F1 offspring. Using a rat model of prenatal low protein (LP, 8% protein) diet followed by a postnatal high fat energy diet (HE, 45% fat) or low fat normal energy diet (NE, 10% fat) for 12 weeks, we investigated the effects of these diets on adiposity, programming of the offspring ATM phenotype, and the associated inflammatory response in adipose tissue. Fat mass in newborn and 12-week old LP fed offspring was lower than that of normal protein (20%; NP) fed offspring; however, the adipose tissue growth rate was higher compared to the NP fed offspring. While LP did not affect the number of CD68+ or CD206+ cells in adipose tissue of NE offspring, it attenuated the number of these cells in offspring fed HE. In offspring fed HE, LP offspring had a lower percentage of CD11c+CD206+ ATMs, whose abundancy was correlated with the size of the adipocytes. Noteworthy, similar to HE treatment, LP increased gene expression of IL-6 within ATMs. Two-way ANOVA showed an interaction of prenatal LP and postnatal HE on IL-6 and IL-1ß transcription. Overall, both LP and HE diets impact ATM phenotype by affecting the ratio of CD11c+CD206+ ATMs and the expression of IL-6.

Modest fructose beverage intake causes liver injury and fat accumulation in marginal copper deficient rats.

OBJECTIVE: Dietary fructose and copper interaction may play an important role in the pathogenesis of nonalcoholic fatty liver disease. In this study, whether or not modest fructose consumption (3% fructose, w/v) (which is more closely related to the American lifestyle with regard to sugar beverage consumption) affects copper status, and causes liver injury and fat accumulation in marginal copper deficient rats was investigated. DESIGN AND METHODS: Male weanling Sprague-Dawley rats were fed either an adequate copper (6 ppm) or a marginally copper deficient (1.6 ppm) diet for 4 weeks. Deionized water or deionized water containing 3% fructose (w/v) was given ad lib. RESULTS: Modest fructose consumption further impaired copper status in the marginal copper deficient rats and increased hepatic iron accumulation. Liver injury and fat accumulation were significantly induced in the marginal copper deficient rats exposed to fructose. CONCLUSIONS: Our data suggest that modest fructose consumption can impair copper status and lead to hepatic iron overload, which in turn, may lead to liver injury and fatty liver in marginal copper deficient rats. This study provides important information on dietary fructose and copper interaction, suggesting that dietary fructose-induced low copper availability might be an important mechanism underlying fructose-induced fatty liver.

Parasite infection is associated with Kaposi's sarcoma associated herpesvirus (KSHV) in Ugandan women.

BACKGROUND: Immune modulation by parasites may influence susceptibility to bacteria and viruses. We examined the association between current parasite infections, HIV and syphilis (measured in blood or stool samples using standard methods) and antibodies against Kaposi's sarcoma herpesvirus (KSHV), measured by ELISA, in 1915 stored plasma samples from pregnant women in Entebbe, Uganda. RESULTS: Seroprevalence of KSHV was higher in women with malaria parasitaemia (73% vs 60% p = 0.01), hookworm (67% vs 56% p = 0.001) and Mansonella perstans (69% vs 59% p = 0.05); seroprevalence increased with increasing intensity of hookworm infection (p < 0.001[trend]). No associations were found for HIV, five other parasites or active syphilis. These effects were not explained by socioeconomic status or education. CONCLUSIONS: Specific parasite infections are associated with presence of antibodies against KSHV, perhaps mediated via their effect on immune function.

Copper deficiency decreases complex IV but not complex I, II, III, or V in the mitochondrial respiratory chain in rat heart.

It has been documented that dietary copper (Cu) deficiency impairs mitochondrial respiratory function, which is catalyzed by 5 membrane-bound multiple protein complexes. However, there are few reports on the simultaneous analysis of Cu effect on the subunit protein expression on all 5 protein complexes. The present study was undertaken to determine the effect of Cu deficiency on each mitochondrial respiratory complex's protein expression in rat heart tissue with western-blot analysis. Male Sprague-Dawley rats were fed diets that were either Cu adequate (6.0 microg Cu/g diet, n = 5) or Cu deficient (0.3 microg Cu/g diet, n = 5) for 5 wk. The monoclonal antibody-based western-blot analysis suggested that the protein levels of 39-kDa and 30-kDa subunits in complex I; 70-kDa and 30-kDa subunits in complex II; core I and core II subunits in complex III; and alpha and beta subunits of F1 complex in complex V in both high-salt buffer (HSB) and low-salt buffer (LSB) protein fractions from heart tissue of Cu-deficient rats did not differ from those of Cu-adequate rats. However, the protein level of cytochrome c oxidase (CCO) subunit (COX) I, COX Vb, and COX VIb subunits in complex IV (CCO) in both HSB and LSB protein fractions from heart tissue of Cu-deficient rats was lower than those of Cu-adequate rats. Collectively, these data demonstrate that Cu deficiency decreases each tested subunit protein expression of complex IV but not those of complex I, II, III, and V in mitochondrial respiratory complexes.

High-fat diet-induced juvenile obesity leads to cardiomyocyte dysfunction and upregulation of Foxo3a transcription factor independent of lipotoxicity and apoptosis.

BACKGROUND: Obesity is associated with dyslipidemia, which leads to elevated triglyceride and ceramide levels, apoptosis and compromised cardiac function. METHODS: To determine the role of high-fat diet-induced obesity on cardiomyocyte function, weanling male Sprague-Dawley rats were fed diets incorporating 10% of kcal or 45% of kcal from fat. Mechanical function of ventricular myocytes was evaluated including peak shortening (PS), time-to-PS (TPS), time-to-90% relengthening (TR90) and maximal velocity of shortening and relengthening (+/- dl/dt). Intracellular Ca properties were assessed using fluorescent microscopy. RESULTS: High-fat diet induced hyperinsulinemic insulin-resistant obesity with depressed PS, +/- dl/dt, prolonged TPS/TR90 reduced intracellular Ca release and Ca clearing rate in the absence of hypertension, diabetes, lipotoxicity and apoptosis. Myocyte responsiveness to increased stimulus frequency and extracellular Ca was compromised. SERCA2a and phospholamban levels were increased, whereas phosphorylated phospholamban and potassium channel (Kv1,2) were reduced in high-fat diet group. High-fat diet upregulated the forkhead transcription factor Foxo3a, and suppressed mitochondrial aconitase activity without affecting expression of the caloric sensitive gene silent information regulator 2 (Sir2), protein nitrotyrosine formation, lipid peroxidation and apoptosis. Levels of endothelial nitric oxide synthase (NOS), inducible NOS, triglycerides and ceramide were similar between the two groups. CONCLUSIONS: Collectively, our data show that high-fat diet-induced obesity resulted in impaired cardiomyocyte function, upregulated Foxo3a transcription factor and mitochondrial damage without overt lipotoxicity or apoptosis.

Dietary copper deficiency reduces iron absorption and duodenal enterocyte hephaestin protein in male and female rats.

The mechanism for reduced Fe absorption in Cu deficiency is unknown, but may involve the intestinal Cu-dependent ferroxidase, Hephaestin (Hp). A 2 x 2 factorial experiment was designed to include Cu-deficient (CuD) and Cu-adequate (CuA) male and female rats. Weanling rats of both sexes were randomly divided into 2 groups each and fed an AIN-93G diet with low (<0.3 mg/kg; CuD) or adequate Cu (5.0 mg/kg; CuA). After 19 d, rats were fed 1.0 g each of their respective diets labeled with (59)Fe. Retained (59)Fe was monitored by whole-body counting for 12 d. Then, rats were killed for (59)Fe and Fe measurements in blood and various organs. Duodenal enterocytes were isolated for Western blot analysis of Hp. Signs of Cu and Fe deficiency were evident in both sexes. CuD male rats absorbed 60% as much Fe as CuA male rats (P < 0.001), whereas CuD female rats absorbed 70% (P < 0.001) as much as CuA females, with no difference between the sexes. Hp protein in enterocytes of CuD rats of both sexes was only 35% of that in CuA rats. The biological half-life of (59)Fe in CuD rats was only 50% (P < 0.001) of that in CuA rats, suggesting that Fe turnover was faster in CuD rats than CuA rats. Serum, spleen, and kidney Fe were lower (P < 0.001) in CuD rats than in CuA rats. Duodenal mucosa and liver Fe were higher (P < 0.01) in CuD male rats than CuA rats. Duodenal Fe but not liver Fe was higher in CuD female rats than CuA rats. Liver Fe was much higher (<0.001) overall in females than males. The data suggest that Cu deficiency reduces Fe absorption in rats through reduced expression of duodenal Hp protein.

Supplemental ascorbate or alpha-tocopherol induces cell death in Cu-deficient HL-60 cells.

Cytochrome c oxidase (CCO) is the Cu-dependent, terminal respiratory complex of the mitochondrial electron transport chain. Inhibition of CCO can promote oxidative stress by increasing mitochondrial production of reactive oxygen species (ROS). Because mitochondria have an important role in apoptosis as both a target and source for ROS, enhanced ROS production resulting from inhibition of CCO by Cu deficiency may trigger apoptosis. The present study focuses on the mitochondrial effects of N,N'-bis(2-aminoethyl)-1,3-propanedi-amine (TET), which inhibits CCO by causing cellular Cu deficiency, and the antioxidants ascorbate and alpha-tocopherol in a human promyelocytic leukemia cell line (HL-60). The following effects were observed: (i) TET reduced both cell growth and viability only in the presence of ascorbate or alpha-tocopherol; (ii) TET reduced CCO activity and increased mitochondrial ROS production as indicated by increased expression of Mn super-oxide dismutase, but the induction of Mn superoxide dismutase was not affected by ascorbate or alpha-tocopherol; (iii) TET acted independently of ascorbate or alpha-tocopherol in disrupting mitochondrial membrane potential; (iv) TET did not increase caspase-8 activity in the absence of ascorbate or alpha-tocopherol; and (v) TET did not increase transfer of cytochrome c from mitochondria to the cytosol unless alpha-tocopherol was present. These findings indicate that reduction in CCO activity by TET-induced Cu deficiency increased oxidative stress in HL-60 cells sufficiently to disrupt the electrochemical gradient of the inner mitochondrial membrane but did not trigger cell death. Also, ascorbate and alpha-tocopherol did not alleviate oxidative stress but may have become pro-oxidants, adding to the oxidant burden sufficiently to trigger cell death in TET-treated cells.

Dietary copper affects azoxymethane-induced intestinal tumor formation and protein kinase C isozyme protein and mRNA expression in colon of rats.

Previous studies have show that changes in protein kinase C (PKC) isoform expression may be related to increased susceptibility of copper-deficient rats to aberrant crypt formation. The purpose of this study was to determine whether dietary copper would affect azoxymethane-induced intestinal tumor formation and PKC isozyme expression in normal colonic mucosa and tumor samples. Eighty weanling Fischer-344 rats were randomly assigned to diets that contained either 0.8 or 5.3 microg Cu/g diet. After 24 and 31 d of diet consumption, 30 rats/diet were administered azoxymethane (15 mg/kg i.p.) and 10 rats/diet were administered saline. Rats continued to consume their respective diets for an additional 38 wk. Rats injected with azoxymethane and fed the low copper diet had a significantly (P < 0.0001) greater small intestinal and total tumor incidence compared with rats fed adequate dietary copper. However, dietary copper did not affect colon tumor incidence. Low dietary copper significantly (P < 0.004) decreased PKC alpha protein expression in normal but not in tumor tissue. In contrast, low dietary copper did not affect PKC delta or zeta protein expression in either the normal or tumor tissue. PKC alpha and delta protein and mRNA expression were lower in tumor tissue than in normal tissue. These results along with previous observations suggest that dietary copper-mediated changes in PKC alpha, delta and zeta protein expression are not as important for colon tumor promotion/progression as they are for tumor initiation.