Adipose Depletion and Apoptosis Induced by Trans-10, Cis-12 Conjugated Linoleic Acid in Mice

Objective: To compare the effectiveness of a conjugated linoleic acid (CLA) isomer mixture (mCLA) with each main isomer [trans-10,cis-12 CLA (CLA10,12) and cis-9,trans-11 CLA (CLA9,11)] in causing body lipid loss and adipose tissue apoptosis. Research Methods and Procedures: Mice selected over 16 generations for high (MH) or low (ML) energy expenditure and a control group (MC) were fed diets containing either soy oil or soy oil plus mCLA, CLA10,12, or CLA9,11 for 5 days in one study and 14 days in a second study. Results: Mice fed mCLA or CLA10,12 had less body lipid (p _ 0.05), smaller retroperitoneal fat pads (p \u3c 0.05), and ate less (p \u3c 0.01) than mice fed no CLA or CLA9,11 for 5 days. Mice consuming 1% mCLA or 0.5% CLA10,12 gained less weight (p \u3c 0.01) and had less body lipid (p \u3c 0.05) and smaller epididymal (p \u3c 0.05) and retroperitoneal fat pads (p \u3c 0.01) than mice consuming either control or 0.5% CLA9,11-containing diets for 14 days. Only mCLA and CLA10,12 increased apoptosis in retroperitoneal fat pads (p \u3c 0.01). The effects of mCLA and CLA10,12 were independent of genetic line except for the effect on adipocyte apoptosis. Mice of the MH line were slightly less sensitive than MC or ML mice to CLA-induced adipose tissue apoptosis. Discussion: CLA10,12, but not CLA9,11, can induce both body fat loss and adipose apoptosis. Although mice of a genotype with less body fat and greater metabolic rate and feed intake appear less sensitive, these CLA effects are robust for mice of varying metabolic background

Effect of resveratrol on fat mobilization

Higher levels of body fat are associated with increased risk for development of numerous adverse health conditions. Phytochemicals are potential agents to inhibit differentiation of preadipocytes, stimulate lipolysis, and induce apoptosis of existing adipocytes, thereby reducing adipose tissue mass. Resveratrol decreased adipogenesis and viability in maturing preadipocytes; these effects were mediated not only through down-regulating adipocyte specific transcription factors and enzymes but also by genes that modulate mitochondrial function. Additionally, resveratrol increased lipolysis and reduced lipogenesis in mature adipocytes. In addition, combining resveratrol with other natural products produced synergistic activities from actions on multiple molecular targets in the adipocyte life cycle. Treatment of mice with resveratrol alone was shown to improve resistance to weight gain caused by a high-fat diet. Moreover, dietary supplementation of aged ovariectomized rats with a combination of resveratrol and vitamin D, quercetin, and genistein not only decreased weight gain but also inhibited bone loss. Combining several phytochemicals, including resveratrol, or using them as templates for synthesizing new drugs, provides a large potential for using phytochemicals to target adipocyte adipogenesis, apoptosis, and lipolysis. © 2011 New York Academy of Sciences

Enhanced inhibition of adipogenesis and induction of apoptosis in 3T3-L1 adipocytes with combinations of resveratrol and quercetin

Certain flavonoids have been shown to have specific effects on biochemical and metabolic functions of adipocytes. In this study, we investigated the effects of combinations of resveratrol and quercetin on adipogenesis and apoptosis in 3T3-L1 cells. In maturing preadipocytes resveratrol and quercetin at 25 μM individually suppressed intracellular lipid accumulation by 9.4 ± 3.9% (p \u3c 0.01) and 15.9 ± 2.5%, respectively, (p \u3c 0.001). The combination of resveratrol and quercetin at the same dose, however, decreased lipid accumulation by 68.6 ± 0.7% (p \u3c 0.001). In addition, combinations of resveratrol and quercetin at 25 μM significantly decreased the expression of peroxisome proliferators-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein (C/EBP)α, both of which act as key transcription factors. In mature adipocytes resveratrol and quercetin at 100 μM individually decreased viability by 18.1 ± 0.6% (p \u3c 0.001) and 15.8 ± 1% (p \u3c 0.001) and increased apoptosis (100 μM) by 120.5 ± 8.3% (p \u3c 0.001) and 85.3 ± 10% (p \u3c 0.001) at 48 h, respectively. Combinations of resveratrol and quercetin further decreased viability (73.5 ± 0.9%, p \u3c 0.001) and increased apoptosis (310.3 ± 9.6%, p \u3c 0.001) more than single compounds alone. The combination of resveratrol and quercetin at 100 μM increased release of cytochrome c from mitochondria to cytosol and decreased ERK 1/2 phosphorylation. Taken together, our data indicate that combinations of resveratrol and quercetin can exert potential anti-obesity effects by inhibiting differentiation of preadipocytes and inducing apoptosis of mature adipocytes. © 2008 Elsevier Inc. All rights reserved

Central leptin versus ghrelin: Effects on bone marrow adiposity and gene expression

This study compared the central effects of ghrelin and leptin on body and bone marrow adiposity and gene expression in adipose tissue and bone marrow. Male Sprague-Dawley rats were injected intracerebroventricular (ICV) twice daily with control, 66 ng ghrelin (G66), 330 ng ghrelin (G330), or 5 μg leptin (L5) for 5 days. Food intake (FI) and body weight (BW) were measured daily. Gene expression in adipose tissue and bone marrow was assessed using RT-PCR. Leptin reduced FI (P \u3c 0.05) and BW (P \u3c 0.05), whereas ghrelin increased BW (P \u3c 0.05) without affecting FI. Leptin decreased fat pad weights, whereas ghrelin (G330) increased fat pad weights (P \u3c 0.05). In epididymal adipose tissue, leptin increased expression of lipolysis marker ADRB2 and thermogenesis marker MFN2 and decreased expression of adipogenic markers, FASN, SLC2A4, and SCD1, whereas ghrelin increased expression of FASN and SCD1. Leptin decreased bone marrow adipocyte size and number; however, ghrelin had no effect on these parameters. In whole bone marrow, leptin decreased expression of FASN and SCD1 and increased expression of DLK1, whereas ghrelin (G330) decreased expression of COL1A1. Thus, leptin induces similar changes in bone marrow and adipose tissue gene expression, reflecting the decreased adiposity in both compartments

Regulation of adipogenesis by medium-chain fatty acids in the absence of hormonal cocktail

We report here that octanoate and decanoate, 8-carbon and 10-carbon medium-chain fatty acids (MCFA), decreased adipogenesis in 3T3-L1 preadipocytes when treated with standard hormonal cocktail, but increased adipogenesis in a dose-dependent manner (with decanoate being more effective) when treated with basal media. Addition of dexamethasone to basal medium with either octanoate or decanoate further increased adipogenesis. In order to understand the adipogenic effects of MCFA in the absence of standard hormonal cocktail, postconfluent 3T3-L1 preadipocytes were treated with octanoate or decanoate, and the change in the expression of several adipogenic transcription factors and enzymes was investigated using real-time RT-PCR. Octanoate and decanoate up-regulated the mRNA expression of peroxisome-proliferator-activated receptor (PPAR) γ, CCAAT/enhancer-binding protein (C/EBP) α, fatty-acid-binding protein, sterol-regulatory element binding protein 1c, lipoprotein lipase and hormone-sensitive lipase, and the protein expression of PPARγ and C/EBPα, with decanoate being more effective. Moreover, the PPARγ antagonist GW9662 inhibited MCFA-induced lipid accumulation by about 50%. Decanoate and octanoate, to a lesser degree, increased lipid accumulation, which was associated with an increase in glycerol-3-phosphate dehydrogenase activity. These results show that octanoate and decanoate may stimulate differentiation of preadipocytes, at least in part, by their influence on the expression of PPARγ and other adipocyte-specific factors. © 2009 Elsevier Inc. All rights reserved

Central (ICV) leptin injection increases bone formation, bone mineral density, muscle mass, serum IGF-1, and the expression of osteogenic genes in leptin-deficient ob/ob mice

Both central and peripheral leptin administrations reduce body weight, food intake, and adiposity in ob/ob mice. In this study we compared effects of intracerebroventricular (ICV) and subcutaneous (SC) administration of leptin on bone metabolism in the appendicular and axial skeleton and adipose tissue gene expression and determined the effects of ICV leptin on bone marrow gene expression in ob/ob mice. In experiment 1, leptin (1.5 or 0.38μg/d) or control was continuously injected ICV for 12 days. Gene expression analysis of femoral bone marrow stromal cells showed that expression of genes associated with osteogenesis was increased after ICV injection, whereas those associated with osteoclastogenesis, adipogenesis, and adipocyte lipid storage were decreased. In experiment 2, leptin was injected continuously ICV (0.0 or 1.5μg/d) or SC (0.0 or 10μg/d) for 12 days. In both experiments, regardless of mode of administration, leptin decreased body weight, food intake, and body fat and increased muscle mass, bone mineral density, bone mineral content, bone area, marrow adipocyte number, and mineral apposition rate. Serum insulin was decreased, whereas serum osteocalcin, insulin-like growth factor 1, osteoprotegerin, pyridinoline, and receptor activator of nuclear factor κB ligand concentrations were increased. In experiment 2, expression of genes in adipose tissue associated with apoptosis, lipid mobilization, insulin sensitivity, and thermogenesis was increased, whereas expression of genes associated with cell differentiation and maturation was decreased regardless of mode of administration. Thus ICV injection of leptin promotes expression of pro-osteogenic factors in bone marrow, leading to enhanced bone formation in ob/ob mice. Copyright © 2011 American Society for Bone and Mineral Research

Preventing bone loss and weight gain with combinations of vitamin d and phytochemicals

Vitamin D and certain natural compounds have been shown to regulate both lipid metabolism and bone formation. Treatments that prevent or reverse age-related increase in bone marrow adiposity could both increase new bone formation and inhibit bone destruction. We tested the hypothesis that dietary supplementation with combinations of vitamin D and phytochemicals inhibits bone loss and decreases adiposity to a greater extent than control or vitamin D-alone diets. Aged ovariectomized female rats (12 months old, n=50, initial body weight=240g) were given control (AIN-93M diet), vitamin D (2,400IU/kg), or vitamin D plus resveratrol (16, 80, or 400mg/kg of diet [low, medium, and high dose, respectively]), quercetin (80, 400, or 2,000mg/kg of diet), and genistein (64, 256, or 1,040mg/kg of diet) for 8 weeks. The high-dose treatment (vitamin D+400mg/kg resveratrol+2,000mg/kg quercetin+1,040mg/kg genistein) reduced body weight gain (P\u3c.05) and the fat pad weights (P\u3c.05). This treatment also increased the serum concentration of insulin-like growth factor-1 (P\u3c.05) and the bone mineral content of the femur. Micro-computed tomography and histomorphometric analyses indicated that the high-dose treatment prevented loss of trabecular bone (P\u3c.05) and reduced marrow adipocytes (P\u3c.001) and osteoclasts (P\u3c.05) compared with the control and vitamin D alone (P\u3c.05). We conclude that aged ovariectomized female rats supplemented with vitamin D combined with genistein, quercetin, and resveratrol had improved bone mineral density and reduced body weight gain and a significant decrease in bone marrow adipocytes. The synergistic effects of a combination of phytochemicals with vitamin D may be effective in reducing bone loss and weight gain after menopause. © Copyright 2011, Mary Ann Liebert, Inc. and Korean Society of Food Science and Nutrition 2011

Synergistic Phytochemicals Fail to Protect Against Ovariectomy Induced Bone Loss in Rats

Menopause induces a loss of bone as a result of estrogen deficiency. Despite pharmaceutical options for the treatment of osteopenia and osteoporosis, many aging women use dietary supplements with estrogenic activity to prevent bone loss and other menopausal-related symptoms. Such supplements are yet to be tested for efficacy against a Food and Drug Administration (FDA) approved medication for menopausal bone loss such as zoledronic acid (ZA). The postmenopausal rat model was used to investigate the efficacy of various synergistic phytochemical blends mixed into the diet for 16 weeks. Retired-breeder, Fischer 344 rats were randomly assigned to sham or ovariectomy surgery and 4 treatment groups: ZA; genistein supplementation; and a low dose and high dose blend of genistein, resveratrol, and quercetin. Ovariectomy resulted in a loss of both trabecular and cortical bone which was prevented with ZA. The phytochemical blends tested were unable to reverse these losses. Despite the lack of effectiveness in preventing bone loss, a significant dose-response trend was observed in the phytochemical-rich diets in bone adipocyte number compared to ovariectomized control rats. Data from this study indicate that estrogenic phytochemicals are not as efficacious as ZA in preventing menopausal-related bone loss but may have beneficial effects on bone marrow adiposity in rats