Risperidone Exacerbates Glucose Intolerance, Nonalcoholic Fatty Liver Disease, and Renal Impairment in Obese Mice.

Risperidone, a second-generation antipsychotic drug used for schizophrenia treatment with less-severe side effects, has recently been applied in major depressive disorder treatment. The mechanism underlying risperidone-associated metabolic disturbances and liver and renal adverse effects warrants further exploration. This research explores how risperidone influences weight, glucose homeostasis, fatty liver scores, liver damage, and renal impairment in high-fat diet (HFD)-administered C57BL6/J mice. Compared with HFD control mice, risperidone-treated obese mice exhibited increases in body, liver, kidney, and retroperitoneal and epididymal fat pad weights, daily food efficiency, serum triglyceride, blood urea nitrogen, creatinine, hepatic triglyceride, and aspartate aminotransferase, and alanine aminotransferase levels, and hepatic fatty acid regulation marker expression. They also exhibited increased insulin resistance and glucose intolerance but decreased serum insulin levels, Akt phosphorylation, and glucose transporter 4 expression. Moreover, their fatty liver score and liver damage demonstrated considerable increases, corresponding to increases in sterol regulatory element-binding protein 1 mRNA, fatty acid-binding protein 4 mRNA, and patatin-like phospholipid domain containing protein 3 expression. Finally, these mice demonstrated renal impairment, associated with decreases in glutathione peroxidase, superoxide dismutase, and catalase levels. In conclusion, long-term administration of risperidone may exacerbate diabetes syndrome, nonalcoholic fatty liver disease, and kidney injury.

Actions of annatto-extracted tocotrienol supplementation on obese postmenopausal women: study protocol for a double-blinded, placebo-controlled, randomised trial.

INTRODUCTION: Obesity is a major health concern in postmenopausal women, and chronic low-grade inflammation contributes to the development of obesity. Cellular studies and high-fat-diet-induced obese mouse model mimicking obesity show the antiobesity effect of annatto-extracted tocotrienols (TT) with antioxidant capability. We aim to assess the safety and efficacy of TT consumption for lipid-related parameters in obese postmenopausal women. METHODS AND ANALYSIS: Eligible obese postmenopausal women will be randomly assigned to placebo group (430 mg olive oil) and TT group (DeltaGold Tocotrienol 70%) for 24 weeks. In the present study, the primary outcome is total/regional fat mass and visceral adipose tissue. The secondary outcomes include lipid profile in serum, mRNA expression of fatty acid synthase and carnitine palmitoyltransferase 1A in fat tissue, oxylipins and endocannabinoids in plasma and adipose tissue, abundance and composition of intestinal microbiome in faeces, high-sensitivity C-reactive protein (hs-CRP) in serum and leptin in serum. Every participant will be evaluated at 0 (prior to starting intervention) and 24 weeks of intervention, except for serum lipid profile and hs-CRP at 0, 12 and 24 weeks. 'Intent-to-treat' principle is employed for data analysis. Hierarchical linear modelling is used to estimate the effects of dietary TT supplementation while properly accounting for dependency of data and identified covariates. To our knowledge, this is the first randomised, placebo-controlled, double-blinded study to determine dietary TT supplementation on an obese population. If successful, this study will guide the future efficacy TT interventions and TT can be implemented as an alternative for obese population in antiobesity management. ETHICS AND DISSEMINATION: This study has been approved by the Bioethics Committee of the Texas Tech University Health Sciences Center, Lubbock. An informed consent form will be signed by a participant before enrolling in the study. The results from this trial will be actively disseminated through academic conference presentation and peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT03705845.

Circulating serum fatty acid synthase is elevated in patients with diabetes and carotid artery stenosis and is LDL-associated.

BACKGROUND AND AIMS: Diabetes is an independent risk factor for carotid artery stenosis (CAS). Fatty acid synthase (FAS), an essential de novo lipogenesis enzyme, has increased activity in the setting of diabetes that leads to altered lipid metabolism. Circulating FAS (cFAS) was recently observed in the blood of patients with hyperinsulinemia and cancer. We thought to evaluate the origin of cFAS and its role in diabetes-associated CAS. METHODS: Patients with diabetes and no diabetes, undergoing carotid endarterectomy (CEA) for CAS, were prospectively enrolled for collection of plaque and fasting serum. FPLC was used to purify lipoprotein fractions, and ELISA was used to quantify cFAS content and activity. Immunoprecipitation (IP) was used to evaluate the affinity of cFAS to LDL-ApoB. RESULTS: Patients with CAS had higher cFAS activity (p < 0.01), and patients with diabetes had higher cFAS activity than patients with no diabetes (p < 0.05). cFAS activity correlated with serum glucose (p = 0.03, r2 = 0.35), and cFAS content trended with plaque FAS content (p = 0.06, r2 = 0.69). cFAS was predominantly in LDL cholesterol fractions of patients with CAS (p < 0.001), and IP of cFAS demonstrated pulldown of ApoB. Similar to patients with diabetes, db/db mice had highest levels of serum cFAS (p < 0.01), and fasL-/- (tissue-specific liver knockdown of FAS) mice had the lowest levels of cFAS (p < 0.001). CONCLUSIONS: Serum cFAS is higher in patients with diabetes and CAS, appears to originate from the liver, and is LDL cholesterol associated. We postulate that LDL may be serving as a carrier for cFAS that contributes to atheroprogression in carotid arteries of patients with diabetes.

Dietary Supplement of Large Yellow Tea Ameliorates Metabolic Syndrome and Attenuates Hepatic Steatosis in db/db Mice.

Yellow tea has been widely recognized for its health benefits. However, its effects and mechanism are largely unknown. The current study investigated the mechanism of dietary supplements of large yellow tea and its effects on metabolic syndrome and the hepatic steatosis in male db/db mice. Our data showed that dietary supplements of large yellow tea and water extract significantly reduced water intake and food consumption, lowered the serum total and low-density lipoprotein cholesterol and triglyceride levels, and significantly reduced blood glucose level and increased glucose tolerance in db/db mice when compared to untreated db/db mice. In addition, the dietary supplement of large yellow tea prevented the fatty liver formation and restored the normal hepatic structure of db/db mice. Furthermore, the dietary supplement of large yellow tea obviously reduced the lipid synthesis related to gene fatty acid synthase, the sterol regulatory element-binding transcription factor 1 and acetyl-CoA carboxylase α, as well as fatty acid synthase and sterol response element-binding protein 1 expression, while the lipid catabolic genes were not altered in the liver of db/db mice. This study substantiated that the dietary supplement of large yellow tea has potential as a food additive for ameliorating type 2 diabetes-associated symptoms.

Dietary starch types affect liver nutrient metabolism of finishing pigs.

This study aimed to evaluate the effect of different starch types on liver nutrient metabolism of finishing pigs. In all ninety barrows were randomly allocated to three diets with five replicates of six pigs, containing purified waxy maize starch (WMS), non-waxy maize starch (NMS) and pea starch (PS) (the amylose to amylopectin ratios were 0·07, 0·19 and 0·28, respectively). After 28 d of treatments, two per pen (close to the average body weight of the pen) were weighed individually, slaughtered and liver samples were collected. Compared with the WMS diet, the PS diet decreased the activities of glycogen phosphorylase, phosphoenolpyruvate carboxykinase and the expression of phosphoenolpyruvate carboxykinase 1 in liver (P0·05). Compared with the WMS diet, the PS diet reduced the expressions of glutamate dehydrogenase and carbamoyl phosphate synthetase 1 in liver (P<0·05). PS diet decreased the expression of the insulin receptor, and increased the expressions of mammalian target of rapamycin complex 1 and ribosomal protein S6 kinase ß-1 in liver compared with the WMS diet (P<0·05). These findings indicated that the diet with higher amylose content could down-regulate gluconeogenesis, and cause less fat deposition and more protein deposition by affecting the insulin/PI3K/protein kinase B signalling pathway in liver of finishing pigs.

Synergistic effects of caffeine and catechins on lipid metabolism in chronically fed mice via the AMP-activated protein kinase signaling pathway.

PURPOSE: To investigate the mechanistic effects of combined exposure to caffeine and catechins on lipid metabolism in mice. METHODS: Seventy mice were randomly assigned to seven groups and fed diets containing varying doses of caffeine and catechins for 24 weeks. Body weight gain, intraperitoneal adipose tissue (IPAT) weight, serum biochemical parameters, and enzymatic activities, mRNA and protein expression levels of lipid metabolism-related enzymes in the liver and IPAT were analyzed. RESULTS: Following administration of caffeine and catechins, body weight gain, IPAT weight, serum and liver concentrations of total cholesterol and triglyceride were markedly reduced. Lipase activities, including that of AMP-activated protein kinase (AMPK), acyl-CoA oxidase, carnitine acyltransferase, adipose triglyceride lipase, and hormone-sensitive lipase, were significantly upregulated; however, fatty acid synthase (FAS) activity in the liver was suppressed. Combined exposure to caffeine and catechins significantly upregulated mRNA and protein expression levels of lipases while downregulating FAS mRNA expression and protein expression of peroxisome proliferator-activated receptor γ2. CONCLUSIONS: The combination of caffeine and catechins regulated the enzymatic activities, mRNA, and protein expression levels of lipid metabolism-related enzymes, resulting in suppression of body weight gain and IPAT weight in mice, potentially through activation of the AMPK signaling pathway. This study indicates that chronic intake of both caffeine and catechins can synergistically contribute to prevention of obesity and lifestyle-related diseases.

Circulating Fatty Acid Synthase in pregnant women: Relationship to blood pressure, maternal metabolism and newborn parameters.

The enzyme FASN (fatty acid synthase) is potentially related with hypertension and metabolic dysfunction. FASN is highly expressed in the human placenta. We aimed to investigate the relationship circulating FASN has with blood pressure, maternal metabolism and newborn parameters in healthy pregnant women. Circulating FASN was assessed in 115 asymptomatic pregnant women in the second trimester of gestation along with C-peptide, fasting glucose and insulin, post-load glucose lipids, HMW-adiponectin and blood pressure (the latter was assessed in each trimester of gestation). At birth, newborns and placentas were weighed. FASN expression was also able to be assessed in 80 placentas. Higher circulating FASN was associated with lower systolic blood pressure (SBP), with a more favourable metabolic phenotype (lower fasting glucose and insulin, post load glucose, HbAc1, HOMA-IR and C-peptide), and with lower placental and birth weight (all p < 0.05 to p < 0.001). Placental FASN expression related positively to circulating FASN (p < 0.005) and negatively to placental weight (p < 0.05). Our observations suggest a physiological role of placental FASN in human pregnancy. Future studies will clarify whether circulating FASN of placental origin does actually regulate placental and fetal growth, and (thereby) has a favourable influence on the pregnant mother's insulin sensitivity and blood pressure.

Fatty acid synthase (FASN) levels in serum of colorectal cancer patients: correlation with clinical outcomes.

Fatty acid synthase (FASN) is a common phenotype to many kinds of human cancers, such as those of the breast, ovary, pancreas, prostate, colon, and so on. Increased FASN levels have been detected in the serum of the patients with breast and pancreatic cancers. The relationship between the FASN level in serum and the clinicopathological characteristics of colorectal cancer is investigated in this study. FASN levels in serum were examined with enzyme-linked immunosorbent assay (ELISA) in 74 patients with colorectal cancer and 40 healthy persons. Pathological and clinical factors associated with FASN concentrations in serum were investigated and analyzed by statistical analysis. The FASN level in colorectal cancer patients' serum is significantly higher than that in healthy persons' serum. FASN levels in the serum of colorectal cancer patients are associated with tumor extent, lymph node metabasis status, distant metastasis, and tumor clinical stage. The 5-year overall survival rate and 5-year disease-free survival rate among patients with low FASN levels in serum are significantly higher than those among patients with high FASN levels in serum (log-rank P = 0.003). The high FASN level in serum is a promising independent predictor of colorectal cancers with advanced phases, late clinical stages, and shorter survival. These results suggest that FASN concentration in serum may be a potential and useful tumor marker.

Depression by a green tea extract of alcohol-induced oxidative stress and lipogenesis in rat liver.

We determined the effects of a green tea extract with 36% alcohol on the blood alcohol content, oxidative stress, lipogenesis, inflammation and liver function of female Wistar rats. Tea alcohol significantly decreased the O2⁻, H2O2 and HOCl amounts via catechins and not caffeine. Thirty days of alcohol gavage improved the level of reactive oxygen species (ROS) in the liver, bile and blood, increased the 4-hydroxynonenal-protein adducts, Kupffer cell infiltration and lipid accumulation in the liver, and elevated the plasma alanine aminotransferase level. A western blot analysis showed reduced expression of the oxidative enzymes (CYP2E1 and NADPH oxidase p47phox protein) and lipogenic enzymes (SREBP-1c and fatty acid synthase) in the alcohol-treated liver. Tea alcohol significantly attenuated these elevated parameters. We conclude that the green tea extract in alcohol efficiently reduced the amounts of O2⁻, H2O2 and HOCl primarily due to the catechin content, and not caffeine. The developed tea liquor attenuated alcohol-induced oxidative injury and lipogenesis in the liver by the synergetic action of catechins and caffeine.

Estrogen sulfotransferase regulates body fat and glucose homeostasis in female mice.

Estrogen regulates fat mass and distribution and glucose metabolism. We have previously found that estrogen sulfotransferase (EST), which inactivates estrogen through sulfoconjugation, was highly expressed in adipose tissue of male mice and induced by testosterone in female mice. To determine whether inhibition of estrogen in female adipose tissue affects adipose mass and metabolism, we generated transgenic mice expressing EST via the aP2 promoter. As expected, EST expression was increased in adipose tissue as well as macrophages. Parametrial and subcutaneous inguinal adipose mass and adipocyte size were significantly reduced in EST transgenic mice, but there was no change in retroperitoneal or brown adipose tissue. EST overexpression decreased the differentiation of primary adipocytes, and this was associated with reductions in the expression of peroxisome proliferator-activated receptor-γ, fatty acid synthase, hormone-sensitive lipase, lipoprotein lipase, and leptin. Serum leptin levels were significantly lower in EST transgenic mice, whereas total and high-molecular-weight adiponectin levels were not different in transgenic and wild-type mice. Glucose uptake was blunted in parametrial adipose tissue during hyperinsulinemic-euglycemic clamp in EST transgenic mice. In contrast, hepatic insulin sensitivity was improved but muscle insulin sensitivity did not change in EST transgenic mice. These results reveal novel effects of EST on adipose tissue and glucose homeostasis in female mice.

Infection with HIV and HCV enhances the release of fatty acid synthase into circulation: evidence for a novel indicator of viral infection.

BACKGROUND: Fatty acid synthase (FASN) is an enzyme synthesized by the liver and plays an important role in lipogenesis. The present study aimed to investigate whether serum FASN concentration may provide a direct link between HIV and/or HCV viral infections and lipid metabolic disorders commonly observed in HIV/HCV-infected patients. METHODS: We evaluated serum FASN concentration in 191 consecutive HIV-infected patients in the absence or presence of HCV co-infection. For comparison, 102 uninfected controls were included. Metabolic and inflammatory phenotype was also compared with respect to the presence of HCV co-infection. RESULTS: Serum FASN concentration was significantly higher in HIV-infected patients than in healthy participants and HCV co-infected patients showed higher levels than those without co-infection. Levels were also affected by treatment regimen, but marginally influenced by virological variables. Insulin concentration was the sole variable among metabolic parameters that demonstrated a significant correlation with serum FASN concentrations. Serum alanine aminotransferase (ALT) values correlated significantly with serum FASN concentration and provided the best discrimination with respect to the presence or absence of HCV co-infection. In multivariate analysis, only ALT, monocyte chemoattractant protein-1 (MCP-1) and the presence of antiretroviral treatment regimen significantly contributed to explain serum FASN concentration in HIV/HCV co-infected patients. CONCLUSION: Serum FASN concentration is significantly increased in HIV-infected individuals. The release of FASN into the circulation is further enhanced in patients who are co-infected with HCV. Subsequent studies should explore the usefulness of this indicator to monitor the effect of viral infections on disease progression and survival.

Extracellular fatty acid synthase: a possible surrogate biomarker of insulin resistance.

CONTEXT: Circulating fatty acid synthase (FASN) is a biomarker of metabolically demanding human diseases. The aim of this study was to determine whether circulating FASN could be a biomarker of overnutrition-induced metabolic stress and insulin resistance in common metabolic disorders. RESEARCH DESIGN AND METHODS: Circulating FASN was evaluated in two cross-sectional studies in association with insulin sensitivity and in four longitudinal studies investigating the effect of diet- and surgery-induced weight loss, physical training, and adipose tissue expansion using peroxisome proliferator-activated receptor agonist rosiglitazone on circulating FASN. RESULTS: Age- and BMI-adjusted FASN concentrations were significantly increased in association with obesity-induced insulin resistance in two independent cohorts. Both visceral and subcutaneous FASN expression and protein levels correlated inversely with extracellular circulating FASN (P = -0.63; P < 0.0001), suggesting that circulating FASN is linked to depletion of intracellular FASN. Improved insulin sensitivity induced by therapeutic strategies that decreased fat mass (diet induced, surgery induced, or physical training) all led to decreased FASN levels in blood (P values between 0.02 and 0.04). To discriminate whether this was an effect related to insulin sensitization, we also investigated the effects of rosiglitazone. Rosiglitazone did not lead to significant changes in circulating FASN concentration. CONCLUSIONS: Our results suggest that circulating FASN is a biomarker of overnutrition-induced insulin resistance that could provide diagnostic and prognostic advantages by providing insights on the individualized metabolic stress.

Correlation of electroretinography b-wave absolute latency, plasma levels of human basic fibroblast growth factor, vascular endothelial growth factor, soluble fatty acid synthase, and adrenomedullin in diabetic retinopathy.

BACKGROUND: We investigated the b-wave latency of electroretinogram (ERG), human basic fibroblast growth factor (b-FGF), vascular endothelial growth factor (VEGF), soluble fatty acid synthase (s-Fas), and adrenomedullin (ADM) in diabetic retinopathy. PATIENTS AND METHODS: Thirty control and 60 type II diabetic women (mean age 45+/-3.9 years, duration of diabetes 10.1+/-2.1 years) were investigated. Diabetics without complications (Group II) and with retinopathy (Group III) were diagnosed depending on clinical findings, abnormal fundus examination, and ERG. Plasma levels of b-FGF, VEGF, s-Fas, and ADM were measured. RESULTS: ERG showed a significant increase of b-wave absolute latency, plasma b-FGF, VEGF, s-Fas, and ADM in diabetic retinopathy (P<.05). A positive correlation was found between b-wave latency and VEGF and s-Fas, and a negative correlation with b-FGF and ADM. CONCLUSION: This study elucidates the causative role of VEGF and s-Fas in diabetic retinopathy. VEGF may potently promote growth of endothelial cells and formation of new vessels implicated in proliferative retinopathy. s-Fas could be involved in advancement of apoptotic changes in retinopathy and high levels of b-FGF, and ADM may be compensatorily neuroprotective and vasculoprotective. The results showed that diabetic retinopathy is the result of multiple factors, so it is optimistic to believe that reversing VEGF or s-Fas will halt retinopathy, targeting multiple mechanisms simultaneously by administering combination treatments of VEGF antagonists; antiapoptotic drugs together with b-FGF and/or ADM may be prospective.

Fatty acid synthase activity regulates HER2 extracellular domain shedding into the circulation of HER2-positive metastatic breast cancer patients.

Clinicopathological assessment of the functional relationship between the HER2 oncogene and tumor-associated fatty acid synthase (FASN) is largely precluded because immunohistochemical and/or mRNA studies should be performed in biopsies from breast cancer patients. We here sought to determine whether serum FASN (sFASN) could associate with circulating HER2 extracellular domain (HER2 ECD) in the blood of metastatic breast cancer (MBC) patients. Concentrations of serum FASN and HER2 ECD were measured with ELISA in sera retrospectively obtained from 201 patients with metastatic breast cancer (MBC) and 31 healthy subjects. Mechanistical in vitro studies were performed using pharmacological inhibitors of HER2 and FASN as well as cultured cancer cells engineered to overexpress HER2 and FASN human genes. When the upper limit of normal sFASN was defined as the mean + 2SD of the control group, sFASN was elevated above this cut-off (12 ng/ml) in 70 MBC patients (35%). Eighty-nine MBC patients (44%) had elevated levels of HER2 ECD (HER2 ECD cut-off = 15 ng/ml). HER2 ECD-positive MBC patients slightly increased their sFASN levels compared with HER2 ECD-negative MBC patients. sFASN-positive MBC patients had significantly increased levels of HER2 ECD when compared with sFASN-negative MBC patients (mean HER2 ECD=34 ng/ml, 95% CI 26-41 ng/ml and 18 ng/ml -95% CI 15-21 ng/ml, respectively; p=0.002). Sixty percent of sFASN-positive patients concurrently exhibited high levels of HER2 ECD whereas 64% of sFASN-negative patients were negative for circulating HER2 ECD. In vitro studies revealed that BC cells bearing HER2 gene-amplification released higher levels of extracellular FASN than HER2-negative BC cells. Trastuzumab-induced blockade of HER2 ECD shedding failed to prevent FASN release and retrovirally-induced HER2 overexpression in MCF-7 cells did not increase extracellular FASN. Of note, pharmacological inhibition of FASN activity significantly decreased HER2 ECD levels in the supernatant of HER2-overexpressing BC cells while transient overexpression of FASN gene in HBL100 cells promoted FASN protein release and concomitantly increased HER2 ECD shedding into the extracellular milieu. Subsequent studies should explore if quantitative determination of FASN molecules in blood could become a rapid and accurate non-invasive test to monitor disease progression and survival in HER2-overexpressing MBC undergoing HER2-targeted therapies.

Serum concentrations of extracellular fatty acid synthase in patients with steatohepatitis.

BACKGROUND: Fatty acid synthase (FASN) is an enzyme synthesized by the liver and plays an important role in lipogenesis. The present study aimed to assess whether serum FASN concentrations are altered in patients with chronic liver disease, and to investigate whether its measurement may be a useful tool in the clinical evaluation of this derangement. METHODS: We investigated 93 patients with chronic liver disease (14 minimal change disease, 79 steatohepatitis) and 100 control subjects. Serum FASN concentrations were measured using ELISA. RESULTS: Patients had a significant increase in serum FASN concentration (p<0.001), which was specifically associated with the hepatic Knodell sub-index III of portal inflammation (p=0.019). In addition, serum FASN concentrations were significantly correlated with the circulating levels of the monocyte chemoattractant protein-1 (MCP-1) (Spearman rho=0.375; p<0.001) and type III procollagen-N-peptide (P-III-P) (Spearman rho=0.297; p<0.001). CONCLUSIONS: Serum FASN concentrations are increased in patients with chronic liver impairment, and are associated with specific histological alterations and biochemical markers of portal inflammation. These data suggest that FASN measurement may contribute significantly to the evaluation of these patients.

Serum fatty acid synthase as a marker of pancreatic neoplasia.

Markers of early pancreatic cancer and its precursors are needed to improve the uniformly poor prognosis of this disease. Fatty acid synthase (FAS) catalyzes the synthesis of long-chain fatty acids and is overexpressed in most human solid tumors. We therefore evaluated serum FAS as a marker of pancreatic adenocarcinoma. FAS expression patterns in primary pancreatic adenocarcinomas, intraductal papillary mucinous neoplasms (IPMN), and chronic pancreatitis tissues were analyzed by immunohistochemistry. Serum FAS levels were determined by ELISA in 102 patients with pancreatic adenocarcinomas, in 42 patients with IPMNs, in 27 patients with chronic pancreatitis, and in 39 healthy control subjects. FAS protein was overexpressed in the ductal epithelium of 343 of 399 primary pancreatic adenocarcinomas (86.0%) and 28 of 30 IPMNs (93.3%), and in the islet and ductal cells in 3 of 54 chronic pancreatitis tissues (5.6%), whereas normal ductal epithelium lacked FAS expression. Serum FAS levels were significantly higher in patients with pancreatic ductal adenocarcinoma (first quartile median, 22.0; 4.5 ng/mL), in patients with IPMNs (20.7; 9.4 ng/mL), and in patients with chronic pancreatitis (31.1; 11.9 ng/mL) than in healthy controls (0; 0 ng/mL). FAS levels declined postoperatively in 8 of 9 patients with pancreatic adenocarcinoma and elevations of their preoperative serum FAS. In conclusion, serum FAS levels are elevated in patients with pancreatic cancer and IPMNs and are associated with neoplastic overexpression of FAS.

A new model ELISA, based on two monoclonal antibodies, for quantification of fatty acid synthase.

A new model ELISA, based on two monoclonal antibodies, was developed for the quantification of fatty acid synthase (FAS). In this sandwich assay, a monoclonal antibody M6 was used as a capture on Nunc MaxiSorp ELISA/EIA Modules and another monoclonal antibody M3, labeled with biotin, was used as a detection antibody. More than 10 molecules of biotin were labeled on the anti-FAS monoclonal antibody using modified biotinylation conditions. The within- and between-run CVs were less than 10%, and the detection limit was 3.22 ng/mL. Recoveries were 98.54-121.95%, averaging 106.05%. The average FAS concentration obtained from the total 55 healthy volunteers blood was 4.07 +/- 1.81 ng/mL, 4.25 +/- 2.14 ng/mL in women (n = 37) and 3.70 +/- 0.74 ng/mL in men (n = 18). When compared with the previously developed polyclonal-monoclonal ELISA, a different pattern of FAS levels was observed in the supernatant of two cultured breast cancer cell lines in a time course study and there was no linear correlation between the two assays using 215 human blood samples. Thus, this new model FAS-ELISA could be used as an independent assay in measuring clinical samples. In summary, this monoclonal-monoclonal FAS-ELISA is sensitive, accurate, and precise in quantification of fatty acid synthase and has potential as a complementary tool in testing clinical samples.

Fatty acid synthase (FAS) expression in human breast cancer cell culture supernatants and in breast cancer patients.

Fatty acid synthase (FAS) is selectively expressed in certain human cancers, including carcinoma of the breast, prostate, colon, ovary, and endometrium, compared to normal human tissues and therefore is a putative tumor marker. In this study, we found FAS concentrations were elevated in cell culture supernatants during cell growth in two human breast cancer cell lines but not other cancer cell lines. A quantitative enzyme-linked immunosorbent assay and Western blot analysis were employed in this study. In addition, serum FAS levels were significantly higher in breast cancer patients with different clinical stages (Stage II: 0.59+/-0.09 units/l, Stage III: 0.79+/-0.13 units/l, and Stage IV: 1.39+/-0.35 units/l) compared with healthy subjects (0.27+/-0.02 units/l, P<0.05). Taken together, our data suggest that FAS expression may be a useful tumor marker for breast cancer and play a role in assessing cancer virulence.

Two-site ELISA for the quantitative determination of fatty acid synthase.

Fatty acid synthase (FAS) is an enzyme which plays a central role in the de novo biosynthesis of fatty acids. FAS is selectively expressed in certain human cancers and therefore is a putative tumor marker. We developed an enzyme-linked immunosorbent assay (ELISA) for measuring FAS, and investigated its expression and clinical features. In this two-site sandwich ELISA, a polyclonal antibody was used as a capture on Nunc MaxiSorp ELISA/EIA modules and a monoclonal antibody labeled with biotin was used as a signal antibody. The assay was linear with no cross-reactivity with other tumor markers. The within- and between-run CVs were <10%, and the detection limit was 0.15 arbitrary Units/l. Recoveries were 92.4-105.1%. FAS was stable in buffer at 4 degrees C for more than 10 days and stable at 37 degrees C for 2 days. In human serum, FAS levels were significantly higher in patients with breast (1.01+/-0.71 Units/l, mean+/-S.D.), prostate (0.79+/-0.76 Units/l), colon (0.89+/-0.49 Units/l), and ovarian (0.84+/-0.9 Units/l) cancers compared to normal subjects (0.27+/-0.09 Units/l, P<0.01). This assay is sensitive, accurate, and precise and can distinguish between patients with various types of cancer and normal subjects.

Plasma lipids and fatty acid synthase activity are regulated by short-chain fructo-oligosaccharides in sucrose-fed insulin-resistant rats.

The aim of this study was to evaluate the chronic effects of a short-chain fructo-oligosaccharide (FOS)-containing diet on plasma lipids and the activity of fatty acid synthase (FAS) in insulin-resistant rats. Normal male Sprague-Dawley rats, 5 wk old, were randomly assigned to two groups and fed either a sucrose-rich diet (S, 575 g sucrose /kg diet and 140 g lipids/kg diet) or a sucrose-rich diet supplemented with 10 g/100 g short-chain fructo-oligosaccharides (S/FOS). A third reference group (R) was fed a standard nonpurified diet (g/kg, 575 g starch, 50 g fat). After 3 wk the sucrose-fed rats (compared with the R group) were characterized by the following: 1) higher insulin responses after a glucose challenge (P < 0.05); 2) heavier liver (P < 0.001) and retroperitoneal adipose tissue (P < 0.01); 3) hypertriglyceridemia (P < 0.0001) and higher plasma free fatty acids (P < 0.0001); and 4) higher fatty acid synthase activity in the liver but a low activity in the adipose tissue (P < 0.001). The addition of FOS to the diet resulted in 11% lower liver weight than in the S group (P < 0.05) and tended to result in lower adipose tissue weight (P < 0.11). Plasma triglycerides and plasma free fatty acids were lower in S/FOS- than in S-fed rats (P < 0.05). Chylomicrons + VLDL, and intermediate density lipoprotein (IDL) concentrations did not differ between groups, nor was plasma cholesterol influenced by diet. Hepatic FAS activity was lower in S/FOS-fed rats than in the S-fed rats (P < 0.05). In adipose tissue, however, this activity tended to be greater in rats fed S/FOS than in rats fed the S diet (P < 0.07). In conclusion, in a rat model of diet-induced (57.5% sucrose and 14% lipids) insulin resistance, the addition of short-chain FOS prevented some lipid disorders, lowered fatty acid synthase activity in the liver and tended to raise this activity in the adipose tissue. Short-chain FOS, in addition to being a nondigestible sweetener with good bulking capacity, might be useful in the treatment of insulin resistance and hyperlipidemia.