Expression prevalence and dynamics of GPCR somatostatin receptors 2 and 3 as cancer biomarkers beyond NET: a paired immunohistochemistry approach.

Somatostatin receptors are clinically validated GPCR biomarkers for diagnosis and treatment of various neuroendocrine tumors (NET). Among the five somatostatin receptors, SST2 and SST3 are associated with apoptosis and cell cycle arrest, making these receptor subtypes better differentiated targets in precision oncology. In this study we performed immunohistochemistry of paired tissue microarrays containing 1125 cores, representing 43 tumor types, each stained for SST2 and SST3. A 12-point immunoreactive scoring (IRS) range was used for interpretation of the staining results. We analyzed the results twice, using the conventional positivity IRS cutoffs ≥ 3 and more stringent ≥ 6. Evaluation of receptors expression dynamics was performed for tumor-nodes-metastases (TNM) defined subgroups (ovarian and hepatocellular adenocarcinomas) as a function of their tumor stage. Our results indicate that two-thirds of tested cores exhibit clinically significant expression of at least SST2 or SST3 (IRS ≥ 6). The expression prevalence of both receptors tends to decline with tumor progression. However, an unexpected upregulation of both SST2 and SST3 reemerged in metastases suggesting conserved receptors genetic potential during tumor life cycle. We suggest that SST2 and SST3 should be further explored as potential biomarkers and therapeutic tools for maximizing the efficiency of somatostatin-based precision oncology of solid tumors beyond NET.

Near-Infrared Fluorescent Activated Polymeric Probe for Imaging Intraluminal Colorectal Cancer Tumors.

Detection and removal of preneoplastic tumors is crucial for successful colorectal cancer (CRC) therapy. Here we describe the design of a Cathepsin B (CB)-activated polymeric probe, P-(GGFLGK-IR783), for imaging CRC tumors established by intrarectal or subcutaneous (s.c.) implantation of human colon cancer cells (SW-480 and HT-29) in mice. Multiple copies of the near-infrared fluorescent (NIRF) dye IR783 were attached to a single HPMA copolymer backbone via a CB-cleavable linker (GFLG), and the influence of the dye loading on the fluorescence quenching and activation by CB was assessed in vitro, ex vivo, and in vivo. The optimal dose and dosing regimen of P-(GGFLGK-IR783) for colonic tumor detection was determined. Increasing the IR783 loading in the copolymer from 2.5 to 20 mol % resulted in quenching of the fluorescence signal that was activated in vitro by the action of CB from different origins. Following intravenous administration, P-(GGFLGK-IR783)7.5% preferentially accumulated in intrarectal and s.c. implanted tumors, allowing tumor visualization after 4 h and even 48 h postadministration. Activation of P-(GGFLGK-IR783)7.5% by CB was clearly detected in s.c. implanted tumors, revealing about a 4-fold increase in the fluorescence signal in tumors vs healthy colon tissue. The probe containing the CB-cleavable linker produced higher fluorescence signal intensity in tumors, relative to the noncleavable probe. These results indicate that P-(GGFLGK-IR783)7.5% may aid in detecting CRC tumors and can help to guide selective removal of polyps during colonoscopic procedures.

In vivo magnetic resonance imaging of pancreatic tumors using iron oxide nanoworms targeted with PTR86 peptide.

To cut the high mortality rate of malignant disease such as pancreatic cancer, development of newly diagnostic probes for early stage detection of tumor lesions is required. Multimodal imaging nanoprobes allowing targeted and real time functional/anatomical imaging of tumors meet the demands. For this purpose, a MRI/optical dual-modality probe based on biodegradable magnetic iron oxide nanoworms has been developed. The cross-linked surface of nanoworms were anchored to fluorescent dyes and to FITC.PTR86; a novel synthetic peptide with high affinity towards somatostatin receptors. Combination of various in vitro techniques including Prussian blue staining, fluorescent microscopy and fluorescence activated cell sorting (FACS) have been performed to explore the interaction of developed nanoprobe with pancreatic tumor cell lines. Together with in vivo studies in a xenograft mouse model of human pancreatic adenocarcinoma and ex vivo investigations, the results show the efficient imaging and targeting of pancreatic tumors by our newly developed nanosystem using both MRI and optical imaging modalities.

Functional Single-Chain Polymer Nanoparticles: Targeting and Imaging Pancreatic Tumors in Vivo.

The development of tools for the early diagnosis of pancreatic adenocarcinoma is an urgent need in order to increase treatment success rate and reduce patient mortality. Here, we present a modular nanosystem platform integrating soft nanoparticles with a targeting peptide and an active imaging agent for diagnostics. Biocompatible single-chain polymer nanoparticles (SCPNs) based on poly(methacrylic acid) were prepared and functionalized with the somatostatin analogue PTR86 as the targeting moiety, since somatostatin receptors are overexpressed in pancreatic cancer. The gamma emitter 67Ga was incorporated by chelation and allowed in vivo investigation of the pharmacokinetic properties of the nanoparticles using single photon emission computerized tomography (SPECT). The resulting engineered nanosystem was tested in a xenograph mouse model of human pancreatic adenocarcinoma. Imaging results demonstrate that accumulation of targeted SCPNs in the tumor is higher than that observed for nontargeted nanoparticles due to improved retention in this tissue.

Effects of antihypertensive and triglyceride-lowering agents on hepatic copper concentrations in rats with fatty liver disease.

Copper deficiency had been suggested to link between fructose-enriched diet (FED) and the development of non-alcoholic fatty liver disease (NAFLD). In this study, we characterized changes in hepatic copper concentrations and hepatic oxidative milieu, in rats with the metabolic syndrome and NAFLD as a result of FED with pharmacological manipulations to reduce blood pressure or plasma triglycerides. Changes in plasma and hepatic copper concentrations were correlated with changes observed in the immunohistochemical hepatic expression of copper-zinc-superoxide dismutase (CuZnSOD; SOD1), metallothionein (MT) and nitrotyrosine (NITT). FED administration was associated with a 2.2-fold reduction in hepatic copper concentrations, a decrease in the hepatic SOD1 expression, disappearance of the hepatic MT expression and increase in the hepatic NITT expression. Bezafibrate administration restored the hepatic copper concentrations and the hepatic SOD1 expression to levels that were observed in the control rats. A significant positive correlation between hepatic copper concentrations and the values of hepatic SOD1 expression of each animal included in this study was found. Administration of either captopril or bezafibrate increased hepatic MT expression, however, to levels that were lower than those observed in the control group. Administration of either amlodipine, or captopril or bezafibrate to the FED rats, had no effect on hepatic NITT expression. NAFLD development in FED rats is associated with a decrease in hepatic copper concentrations that is associated with a decrease in the hepatic SOD1 expression. Bezafibrate administration increases hepatic copper concentrations and restores the hepatic SOD1 expression.

Near infrared optical visualization of epidermal growth factor receptors levels in COLO205 colorectal cell line, orthotopic tumor in mice and human biopsies.

In this study, we present the applicability of imaging epidermal growth factor (EGF) receptor levels in preclinical models of COLO205 carcinoma cells in vitro, mice with orthotopic tumors and ex vivo colorectal tumor biopsies, using EGF-labeled with IRDye800CW (EGF-NIR). The near infrared (NIR) bio-imaging of COLO205 cultures indicated specific and selective binding, reflecting EGF receptors levels. In vivo imaging of tumors in mice showed that the highest signal/background ratio between tumor and adjacent tissue was achieved 48 hours post-injection. Dissected colorectal cancer tissues from different patients demonstrated ex vivo specific imaging using the NIR bio-imaging platform of the heterogeneous distributed EGF receptors. Moreover, in the adjacent gastrointestinal tissue of the same patients, which by Western blotting was demonstrated as EGF receptor negative, no labeling with EGF-NIR probe was detected. Present results support the concept of tumor imaging by measuring EGF receptor levels using EGF-NIR probe. This platform is advantageous for EGF receptor bio-imaging of the NCI-60 recommended panel of tumor cell lines including 6-9 colorectal cell lines, since it avoids radioactive probes and is appropriate for use in the clinical setting using NIR technologies in a real-time manner.

Effects of antihypertensive and triglyceride lowering agents on splenocyte apoptosis in rats with fatty liver.

Individuals with the metabolic syndrome (MS) and non-alcoholic fatty liver disease (NAFLD) have an increased incidence of infection and infection-related mortality. Rats given fructose-enriched diet (FED) develop the MS including NAFLD. In this study, we characterized changes in splenocyte apoptosis in FED rats given medications to treat various components of the MS. Apoptosis of splenocytes may induce immunosuppression. Splenocyte apoptosis was evaluated by activated caspase-3 immunohistochemistry in the periarterial sheath (PALS), (a T cell area), follicles (B cell area), marginal (B cell area) and in the red pulp zones. FED administration caused an enormous increase in splenocyte apoptosis in all of the spleen zones: PALS (+2966%), follicles (+3025%), marginal (+5228%) and red pulp (+7000%). Administration of captopril to the FED rats was associated with a further increase in the splenocyte apoptosis only in the marginal (150%), PALS (+105%) and red pulp (+67%) zones. Bezafibrate administration to the FED rats was associated with no further increase in apoptosis rates. Amlodipine administration to the FED rats was associated with almost complete amelioration of the splenocyte apoptosis that was induced by the FED diet. These pharmacological manipulations were also associated with changes in the hepatic lipids composition, and oxidative milieu that did not correlate to the changes in splenocyte apoptosis. NAFLD in FED rats is associated with an increase in splenic apoptosis. Agents administered to treat components of the MS in FED rats may lead to divergent changes in the splenic histology and splenocyte apoptosis.

Bio-imaging of colorectal cancer models using near infrared labeled epidermal growth factor.

Novel strategies that target the epidermal growth factor receptor (EGFR) have led to the clinical development of monoclonal antibodies, which treat metastatic colorectal cancer (mCRC) but only subgroups of patients with increased wild type KRAS and EGFR gene copy, respond to these agents. Furthermore, resistance to EGFR blockade inevitably occurred, making future therapy difficult. Novel bio-imaging (BOI) methods may assist in quantization of EGFR in mCRC tissue thus complementing the immunohistochemistry methodology, in guiding the future treatment of these patients. The aim of the present study was to explore the usefulness of near infrared-labeled EGF (EGF-NIR) for bio-imaging of CRC using in vitro and in vivo orthotopic tumor CRC models and ex vivo human CRC tissues. We describe the preparation and characterization of EGF-NIR and investigate binding, using BOI of a panel of CRC cell culture models resembling heterogeneity of human CRC tissues. EGF-NIR was specifically and selectively bound by EGFR expressing CRC cells, the intensity of EGF-NIR signal to background ratio (SBR) reflected EGFR levels, dose-response and time course imaging experiments provided optimal conditions for quantization of EGFR levels by BOI. EGF-NIR imaging of mice with HT-29 orthotopic CRC tumor indicated that EGF-NIR is more slowly cleared from the tumor and the highest SBR between tumor and normal adjacent tissue was achieved two days post-injection. Furthermore, images of dissected tissues demonstrated accumulation of EGF-NIR in the tumor and liver. EGF-NIR specifically and strongly labeled EGFR positive human CRC tissues while adjacent CRC tissue and EGFR negative tissues expressed weak NIR signals. This study emphasizes the use of EGF-NIR for preclinical studies. Combined with other methods, EGF-NIR could provide an additional bio-imaging specific tool in the standardization of measurements of EGFR expression in CRC tissues.

Hepatic effects of rosiglitazone in rats with the metabolic syndrome.

Rats given fructose-enriched diet develop many characteristics of the human metabolic syndrome and non-alcoholic fatty liver disease. In this study, we characterized the hepatic effects of rosiglitazone in fructose-enriched diet rats. Rats were randomly divided into three groups. One group was maintained on standard rat chow diet for 6 weeks, whereas the other two groups were given fructose-enriched diet for 6 weeks. Four weeks after the initiation of fructose-enriched diet, one of the fructose-enriched diet groups was also given rosiglitazone (10 mg/kg/day) for an additional 2 weeks. Rosiglitazone administration to the fructose-enriched diet rats was associated with decreases in the following parameters: blood pressure (-17%), plasma triglycerides (-62%), hepatic total lipids (-19%), hepatic triglycerides (-61%), hepatic malondialdehyde (-88%), glutathione reductase activity (-84%). An increase in adiponectin plasma levels (+329%), hepatic phospholipids (+46%), hepatic alpha-tocopherol concentrations (+24%) and hepatic paraoxonase activity (+68%) was observed. Rosiglitazone caused a decrease in hepatic macrovesicular steatosis score but no change in hepatic fibrosis. Administration of rosiglitazone, to rats with the metabolic syndrome has limited hepatic favourable effects: it improves hepatic lipid metabolism, decreases macrovesicular steatosis and improves some of the hepatic oxidative-anti-oxidative milieu but has no effect on hepatic fibrosis.

Metabolic syndrome: comparison of the two commonly used animal models.

BACKGROUND: The etiology of the metabolic syndrome (MS) includes both genetic and environmental factors. The two most commonly studied animal models of the MS are the high-sucrose diet given to spontaneously hypertensive rats (SHRs) and high-fructose diet given to Sprague Dawley rats (SDRs). This study compares between these two models. METHODS: The two rat strains were examined; within each group, the rats were assigned to either the high-sugar diet (SDRs with fructose-enriched diet and SHRs with sucrose-enriched diet) or standard rat chow (control group). The rats were followed for 7 weeks. The main MS components (obesity, hypertension, impaired glucose tolerance, hyperinsulinemia, hypertriglyceridemia, and hypercholesterolemia) were measured. RESULTS: At baseline systolic blood pressure (SBP), fasting blood levels of triglycerides and insulin, as well as glucose intolerance, were significantly higher among the SHRs compared to SDRs. Following fructose enrichment, SDRs became hyperinsulinemic, hypertriglyceridemic, hypercholesterolemic, hypertensive, and insulin resistant, whereas SHRs responded to sucrose supplementation by a significant elevation in blood pressure and mild worsening of insulin resistance. Endpoint results revealed superiority of sucrose--SHR model in terms of hypertension and superiority of fructose--SDR model in terms of hyperinsulinemia, hypertriglyceridemia, and hypercholesterolemia. Both models showed similar postintervention degree of glucose tolerance. CONCLUSIONS: The fructose-fed SDR model represents a predominantly environmentally acquired MS, whereas the SHR model is less affected by dietary intervention and better displays the predominantly genetic spontaneous appearance of the syndrome. This fundamental difference should be taken into consideration when choosing an animal model to study the MS.

Diagnostic targeting of colon cancer using a novel fluorescent somatostatin conjugate in a mouse xenograft model.

Colorectal carcinoma is one of the more prevalent, highly malignant human tumors, occurring in about 7% of the population. However, if diagnosed and treated in its early stages, colon cancer is curable. In our study, we used a mouse xenograft model to investigate the capability of a fluorescent conjugate of a novel synthetic somatostatin (SST) analog to improve detection of human colorectal tumors that are characterized by over-expressed SST receptors. Human HT-29 colon carcinomas were induced in nude mice. After administration of the fluorescent SST conjugate, in vivo low- and high-magnification fluorescence microscopy, as well as high-resolution spectrally resolved imaging were performed, and the time-dependent biodistribution was determined quantitatively (using fiber-optic spectroscopy). Administration of the conjugate (at concentrations of 6 mg/kg body weight) enabled targeting small (1-5 mm diameter) tumors with high sensitivity and selectivity. Toxicity studies at dosages up to 1,000 mg/kg body weight did not reveal any drug related abnormalities. In conclusion, the SST conjugate significantly enhanced the detection of HT-29 colon tumors by fluorescence imaging because of a 5- to 8-fold increase in the contrast between malignant and normal tissues.

Effects of amlodipine, captopril, and bezafibrate on oxidative milieu in rats with fatty liver.

Oxidative stress may initiate significant hepatocyte injury in subjects with fatty liver. We characterized changes in hepatic oxidative anti-oxidative parameters in rats given a fructose-enriched diet (FED) with and without medications to reduce blood pressure or plasma triglycerides. FED rats had an increase in malondialdehyde (MDA) concentration, a reduction in alpha-tocopherol concentration, a reduction in paraoxonase (PON) activity, an increase in glutathione peroxidase (GSH-Px), and glutathione reductase (GSSG-R) activity. Amlodipine increased PON and GSH-Px, but decreased GSSG-R activity and alpha-tocopherol concentration. Captopril decreased MDA concentration and the activity of both GSH-Px and GSSG-R, but increased alpha-tocopherol concentration and PON activity. Bezafibrate increased alpha-tocopherol concentration and PON activity, but decreased the activity of GSSG-R. Animals with fatty liver exhibit an increase in peroxidative stress but also a defect in anti-oxidative pathways. Drugs administered to treat hypertension and hypertriglyceridemia could lead to a variety of changes in the hepatic oxidative, anti-oxidative milieu.

Effect of PPAR-gamma agonist on adiponectin levels in the metabolic syndrome: lessons from the high fructose fed rat model.

BACKGROUND: The health hazard of the metabolic syndrome (MS) is increasing, yet there is no effective pharmacologic treatment to this entity as a whole. Recently, hypoadiponectinemia was found to play an important role in the development of MS. We studied the effect of the PPAR-gamma agonist rosiglitazone on adiponectin and the metabolic profile in the fructose-induced hypertensive, hyperinsulinemic, hypertriglyceridemic rat model. METHODS: Thirty male Sprague-Dawley rats were divided into three groups. Ten were fed standard rat chow for 5 weeks, 10, a fructose-enriched diet for 5 weeks, and 10, a fructose-enriched diet for 5 weeks, with rosiglitazone 10 mg/kg/d added during the last 2 weeks. Blood pressure (BP), oral glucose tolerance test (OGTT), plasma insulin, triglycerides, and adiponectin were recorded, as well as mRNA levels of the adiponectin gene in visceral adipose tissue. RESULTS: Fructose-fed rats developed MS as manifested by the increase in systolic BP (from 139 +/- 3 to 158 +/- 4 mm Hg, P < .05), insulin (from 26 +/- 1.6 to 40 +/- 2.5 muU/mL, P < .05), triglycerides (from 91 +/- 9 to 304 +/- 24 mg/dL, P < .05), and impaired OGTT (area under the curve from 13,894 +/- 246 to 17,725 +/- 700 mg/dL/min). Treatment with rosiglitazone reversed these effects and reduced BP to 133 +/- 7 mm Hg, insulin levels to 30 +/- 2.8 muU/mL, triglycerides to 116 +/- 9 mg/dL, and the OGTT to 15,415 +/- 372 mg/dL/min (P < .05 for all variables). In addition, rosiglitazone increased plasma levels of adiponectin fourfold from 4.3 +/- 0.1 to 18.4 +/- 0.6 mug/mL (P < .05). This increase was coupled with 3.8-fold increase in adiponectin mRNA in visceral adipose tissue. CONCLUSIONS: This study shows for the first time that in an animal model of MS, the insulin sensitizer, rosiglitazone, improves the metabolic profile and increases plasma levels of adiponectin and its gene expression. It is possible therefore that rosiglitazone exerts its beneficial effects by increasing the levels of adiponectin.

The effects of S-allylmercaptocaptopril, the synthetic product of allicin and captopril, on cardiovascular risk factors associated with the metabolic syndrome.

Pure allicin, prepared biosynthetically by reacting synthetic alliin with an immobilized alliinase enzyme, is known to possess cardioprotective effects. However, in its pure form, allicin is pharmacologically unstable. S-allylmercaptocaptopril (CPSSA) is a new stable synthetic compound produced by chemical reaction between allicin and the angiotensin converting enzyme inhibitor captopril. Using the fructose-induced metabolic syndrome rat model we studied the effects of short-term treatment with two doses of CPSSA on cardiovascular risk factors associated with the metabolic syndrome, in comparison to the effects of allicin and captopril separately. Allicin (8 mg/(kg day)) significantly reduced insulin, triglycerides, and homocysteine concentrations, and had a slight effect on SBP. Captopril (50mg/(kg day)) only improved blood pressure and homocysteine. Treatment with low dose of CPSSA (5mg/(kg day)) lowered SBP but did not improve any other measured parameter, while treatment with a higher dose (50mg/(kg day)) significantly decreased blood pressure, triglycerides, and homocysteine concentrations. We conclude that the combined molecule CPSSA integrates the anti-hypertensive, lipid-lowering, and homocysteine-reducing effects of both allicin and captopril, making it a potential cardiovascular protective agent.

Fructose-induced fatty liver disease: hepatic effects of blood pressure and plasma triglyceride reduction.

The most known risk factor for nonalcoholic fatty liver disease (NAFLD) is the metabolic syndrome. In this study, we characterized changes in liver pathology, hepatic lipid composition, and hepatic iron concentration (HIC) occurring in rats given fructose-enriched diet (FED), with and without therapeutic maneuvers to reduce blood pressure and plasma triglycerides. Rats were given FED or standard rat chow for 5 weeks. Rats on FED were divided into 4 groups: receiving amlodipine (15 mg/kg per day), captopril (90 mg/kg per day), bezafibrate (10 mg/kg per day) in the last 2 weeks, or a control group that received FED only. FED rats had hepatic macrovesicular and microvesicular fat deposits develop, with increase in hepatic triglycerides (+198%) and hepatic cholesterol (+89%), but a decrease in hepatic phospholipids (-36%), hypertriglyceridemia (+223%), and hypertension (+15%), without increase in HIC. Amlodipine reduced blood pressure (-18%), plasma triglycerides (-12%), but there was no change in hepatic triglycerides and phospholipids concentrations. Captopril reduced blood pressure (-24%), plasma triglycerides (-36%), hepatic triglycerides (-51%), and hepatic macrovesicular fat (-51%), but increased HIC (+23%), with a borderline increase in hepatic fibrosis. Bezafibrate reduced plasma triglycerides (-49%), hepatic triglycerides (-78%), hepatic macrovesicular fat (-90%), and blood pressure (-11%). We conclude that FED rats can be a suitable model for human NAFLD. Drugs administered to treat various aspects of the metabolic syndrome could have hepatic effects. An increase in HIC in rats with NAFLD could be associated with increased hepatic fibrosis.

Risk reduction therapy for syndrome X: comparison of several treatments.

BACKGROUND: Syndrome X, also termed the metabolic syndrome, is a cluster of physiologic and metabolic abnormalities including abdominal obesity, hyperinsulinemia, dyslipidemia and hypertension. Severe cardiovascular morbidity is associated with this pre-diabetic syndrome. We recently suggested that hyperhomocysteinemia is affiliated with this syndrome and thereby contributes to the vascular risk accompanying this condition. The present study compared the effects of antihypertensive, lipid-lowering, and insulin-sensitizing agents on the above-mentioned components of this metabolic syndrome. METHODS: Experimental metabolic syndrome was induced in Sprague-Dawley rats by feeding them a fructose-enriched diet (FED) for 5 weeks. During the last 2 weeks, the rats were treated with amlodipine, captopril, bezafibrate, or rosiglitazone in addition to FED. The control group did not receive any medication. Another control group was fed standard rat chow for 5 weeks. Post- and pretreatment measurements of body weight, systolic blood pressure (SBP), fasting plasma insulin, triglycerides, and total homocysteine concentrations were compared. RESULTS: Amlodipine reduced SBP but did not show metabolic impact. Bezafibrate improved SBP, triglycerides, and insulin but induced elevation of homocysteine levels. Captopril and rosiglitazone remarkably improved SBP, insulin, triglycerides, and total homocysteine levels. In addition, rosiglitazone alone promoted weight gain. CONCLUSIONS: The results indicate that captopril and rosiglitazone have a greater cardiovascular protective potential than amlodipine or bezafibrate. Captopril would be the best choice for patients with metabolic syndrome in whom hypertension and obesity are prominent, whereas rosiglitazone would be the preferred drug when glucose and other metabolic parameters are disturbed.

The effects of allicin on weight in fructose-induced hyperinsulinemic, hyperlipidemic, hypertensive rats.

BACKGROUND: Commercially available garlic preparations in the form of garlic oil, garlic powder and pills are widely used for certain therapeutic purposes, including lowering blood pressure and improving lipid profile. Despite the impressive effects of garlic most studies are limited by lack of controlled methods and suitable double-blinding, and by the use of preparations with unknown amounts and chemical identification of the active ingredient. Allicin, a synthetic preparation of an active constituent of garlic, was found to lower blood pressure, insulin, and triglycerides levels in fructose-fed rats. Thus, it was considered important to assess its effect on the weight of the animals. METHODS: Male Sprague-Dawley rats weighing 240 to 250 g were fed a fructose-enriched diet consisting of 21% protein, 5% fat, 60% carbohydrate, 0.49% sodium and 0.49% potassium for 5 weeks, which produced hyperinsulinemia, hypertension, and hypertriglyceridemia. Group I (controls) rats were fed a diet enriched by fructose only; group II was given allicin the last 2 weeks, and group III was given allicin the first 3 weeks. The three groups consumed the same amount of food. Weight was measured at the beginning of the experiment and after 3 and 5 weeks on the diet. RESULTS: Weight in the control group rose from 249.4 +/- 10.04 g to 274.5 +/- 15.5 g after 3 weeks and to 306.9 +/- 22.2 g after 5 weeks. Weight in group II rose from baseline 259.1 +/- 12.1 g to 306.9 +/- 22.2 g after 3 weeks on fructose alone, and declined slightly to 282.4 +/- 17.4 g after 2 weeks of allicin (P <.02). In group III, in which the protocol was reversed, the baseline weight of 260.4 +/- 13.25 g rose only to 269.8 +/-15.3 g (P <.431) after 3 weeks on fructose and allicin. CONCLUSIONS: The control group that was fed a diet enriched by fructose alone continued to gain weight, whereas the groups fed allicin did not. The difficulty of preventing weight gain after reaching the nadir of weight loss underscores the practical value of allicin for weight control.

Hyperhomocysteinemia as a component of syndrome X.

Syndrome X, a cluster of several metabolic disorders that includes hyperinsulinemia, hypertriglyceridemia, and hypertension, is associated with severe vascular morbidity. Hyperhomocysteinemia is another risk factor for cardiovascular and cerebrovascular diseases, often exhibited by insulin-resistant patients. In the current study, we investigated the relationship between syndrome X and hyperhomocysteinemia in a rat model. Two groups of rats were fed either fructose-enriched diet or standard rat chow for 5 weeks. Systolic blood pressure (SBP), as well as fasting plasma insulin, triglycerides, total cholesterol, and total homocysteine levels, were determined at the beginning and at the end of the study. A complete metabolic syndrome was induced by the fructose-enriched diet, including hyperinsulinemia, hypertriglyceridemia, and hypertension. Homocysteine concentration was 72% higher after 5 weeks on the fructose diet (8.49 +/- 1.6 v 4.92 +/- 0.9 micromol/l, P<.01). Insulin, triglycerides, SBP, and homocysteine levels were insignificantly changed during 5 weeks on standard rat chow. Homocysteine was positively and significantly correlated with any original component of syndrome X (r=0.565, P=.014 with insulin, r=0.662, P=.001 with triglycerides, and r=0.774, P<.001 with SBP). The results of the present study indicate that hyperhomocysteinemia is an integral component of this rat model of syndrome X. It is thus highly likely that hyperhomocysteinemia is an integral component of the human syndrome X as well, and thereby contributes to the overall high vascular risk associated with this condition.