A novel complex of arginine-silicate improves micro- and macrovascular function and inhibits glomerular sclerosis in insulin-resistant JCR:LA-cp rats

Impact of the arginine silicate inositol complex on bone metabolism in broiler chickens with tibial dyschondroplasia caused by manganese deficiency

1. Tibial dyschondroplasia (TD) is a skeletal disorder in broilers that has financial implications, necessitating dietary modifications to reduce the prevalence of this disease. This study explored how arginine silicate inositol complex (ASI) supplementation affected tibial growth plate (TGP) and overall bone health in broilers with manganese (Mn) deficiency-induced TD.2. A total of 240 broiler chicks were divided into four groups, each consisting of 60 birds (15 replicates of four broilers each) as follows: i) Control, with 60 mg Mn per kg of diet; ii) ASI, with 60 mg Mn and 1 g ASI per kg of diet; iii) TD, with 22 mg Mn per kg of diet, and iv) TD+ASI, with 22 mg Mn and 1 g ASI per kg of diet.3. It was found that ASI supplementation increased tibial bone length in Mn-deficient TD broilers (p = 0.007). There was no Mn x ASI interaction for other bone morphometry variables (p > 0.05). However, both tibial bone mineral content and density were affected by Mn and ASI (p < 0.05). With ASI supplementation, serum bone-specific alkaline phosphatase and osteocalcin levels were elevated in the TD+ASI group compared to the TD group (p < 0.001). In the TD group, osteoprotegerin (OPG) levels in the TGP decreased compared to the control groups (p < 0.001).4. In contrast, ASI supplementation in the TD broilers counteracted the decrease in OPG compared to TD broilers without ASI supplementation (p < 0.001). The Mn level and ASI supplementation significantly influenced the OPG/receptor activator of the nuclear factor-κB ligand ratio (p < 0.001).5. In conclusion, the results demonstrated that inclusion of ASI in broiler diets could enhance bone formation variables by controlling OPG levels in the TGP, potentially serving as an effective method to decrease the occurrence of TD.

The Protective Effects of a Combination of an Arginine Silicate Complex and Magnesium Biotinate Against UV-Induced Skin Damage in Rats

The purpose of this study was to observe the effects of a novel combination of inositol-stabilized arginine silicate complex (ASI) and magnesium biotinate (MgB) on the prevention of skin damage after UVB exposure in rats. Forty-nine Sprague-Dawley rats were randomized into one of the following groups: (1) NC, normal control, (2) SC, shaved control, (3) UVB (exposed to UVB radiation), (4) ASI+MgB-L (Low Dose), (5) ASI+MgB-H (High Dose), (6) ASI+MgB-L+MgB cream, (7) ASI+MgB-H+MgB cream. The results showed that ASI+MgB treatment alleviated the macroscopic and histopathological damages in the skin of rats caused by UVB exposure. Skin elasticity evaluation showed a similar trend. ASI+MgB increased serum Mg, Fe, Zn, Cu, Si, biotin, and arginine concentrations and skin hydroxyproline and biotinidase levels while decreasing skin elastase activity (p < 0.05) and malondialdehyde (MDA) concentration (p < 0.001). Moreover, ASI+MgB treatment increased skin levels of biotin-dependent carboxylases (ACC1, ACC2, PC, PCC, MCC) and decreased mammalian target of rapamycin (mTOR) pathways and matrix metalloproteinase protein levels by the regulation of the activator protein 1 (AP-1), and mitogen activated protein kinases (MAPKs) signaling pathways. In addition, ASI+MgB caused lower levels of inflammatory factors, including TNF-α, NFκB, IL-6, IL-8, and COX-2 in the skin samples (p < 0.05). The levels of Bax and caspase-3 were increased, while anti-apoptotic protein Bcl-2 was decreased by UVB exposure, which was reversed by ASI+MgB treatment. These results show that treatment with ASI and MgB protects against skin damage by improving skin appearance, elasticity, inflammation, apoptosis, and overall health.

Effect of inositol -stabilized arginine silicate on arthritis in a rat model

The purpose of this study was to test the effects of arginine-silicate-inositol complex (ASI), compared to a combination of the individual ingredients (A+S+I) of the ASI, on inflammatory markers and joint health in a collagen-induced arthritis (CIA) rat model. A total of 28 Wistar rats were divided into four groups: (i) Control; (ii) Arthritic group, rats subjected to CIA induction by injection of bovine collagen type II (A); (iii) Arthritic group treated with equivalent doses of the separate components of the ASI complex (arginine hydrochloride, silicon, and inositol) (A+S+I); (iv) Arthritic group treated with the ASI complex. The ASI complex treatment showed improved inflammation scores and markers over the arthritic control and the A+S+I group. ASI group had also greater levels of serum and joint-tissue arginine and silicon than the A+S+I group. Joint tissue IL-6, NF-κB, COX-2, TNF-α, p38 MAPK, WISP-1, and β-Catenin levels were lower in the ASI group compared to the other groups (P < 0.05 for all). In conclusion, these results demonstrate that the ASI complex may be effective in reducing markers of inflammation associated with joint health and that the ASI complex is more effective than a combination of the individual ingredients.

Effects of dietary supplementation of arginine-silicate-inositol complex on absorption and metabolism of calcium of laying hens

The effects of supplementation of arginine-silicate-inositol complex (ASI; 49.5–8.2–25 g/kg, respectively) to laying hens were investigated with respect to eggshell quality, calcium (Ca) balance, and expression of duodenal proteins related to Ca metabolism (calbindin and tight junction proteins). A total of 360 laying hens, 25 weeks old, were divided into 3 groups consisting of 6 replicate of cages, 20 birds per cage. The groups were fed a basal diet and the basal diet supplemented with 500 or 1000 mg ASI complex per kilogram for 90 days. Data were analyzed by ANCOVA using data during the first week of the adaptation period as covariates. As the ASI complex supplementation level increased, there were increases in feed intake (P < 0.0001), egg production (P < 0.001), egg weight (P < 0.0001) and eggshell weight (P < 0.001) weight, and shell thickness (P < 0.001) and decreases in feed conversion ratio and cracked egg percentage (P < 0.0001 for both). Concentrations of serum osteocalcin (P < 0.0001), vitamin D (P < 0.0001), calcium (P < 0.001), phosphorus (P < 0.001), and alkaline phosphatase (P < 0.008) as well as amounts of calcium retention (P < 0.0001) and eggshell calcium deposition (P < 0.001), and Ca balance (P < 0.0001) increased, whereas amount of calcium excretion (P < 0.001) decreased linearly in a dose-dependent manner. The ASI complex supplementation increased expressions of calcium transporters (calbindin-D28k, N sodium-calcium exchanger, plasma membrane calcium ATPase, and vitamin D receptor) and tight junction proteins (zonula occludens-1 and occludin) in the duodenum in a linear fashion (P < 0.0001 for all). In conclusion, provision of dietary ASI complex to laying hens during the peak laying period improved eggshell quality through improving calcium utilization as reflected by upregulation of genes related to the calcium metabolism. Further studies are needed to elucidate the contribution of each of the ASI complex ingredients.

Arginine Silicate Inositol Complex Accelerates Cutaneous Wound Healing

Arginine silicate inositol (ASI) complex is a composition of arginine, silicon, and inositol that has been shown to have beneficial effects on vascular health. This study reports the effects of an ASI ointment on wound healing in rats. A full-thickness excision wound was created by using a disposable 5 mm diameter skin punch biopsy tool. In this placebo-controlled study, the treatment group's wound areas were covered by 4 or 10 % ASI ointments twice a day for 5, 10, or 15 days. The rats were sacrificed either 5, 10, or 15 days after the wounds were created, and biopsy samples were taken for biochemical and histopathological analysis. Granulation tissue appeared significantly faster in the ASI-treated groups than in the control groups (P < 0.05). The mean unhealed wound area was significantly smaller, and the mean percentage of total wound healing was significantly higher in ASI-treated wounds than in the control wounds. Hydroxyproline, collagen, and matrix metalloproteinases were measured in the granulated tissue and found to be affected. Inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), collagen, matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), epidermal growth factor (EGF), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and various cytokines (TNF-α and IL-1β) measured in this study showed a significant fall in expression level in ASI-treated wounds. The results suggest that topical application of ASI ointment (especially 4 % concentration) has beneficial effects on the healing response of an excisional wound.

Dietary arginine silicate inositol complex inhibits periodontal tissue loss in rats with ligature-induced periodontitis

The purpose of this study was to induce experimental periodontitis in rats previously fed diets containing arginine silicate inositol (ASI) complex and examine the biochemical, immunological, and radiological effects. Fifty two 8-week-old female Sprague Dawley rats were equally divided into four groups. The control group included those fed a standard rat diet with no operation performed during the experiment. The periodontitis, ASI I, and ASI II groups were subjected to experimental periodontitis induction for 11 days after being fed a standard rat diet alone, a diet containing 1.81 g/kg ASI complex, or a diet containing 3.62 g/kg ASI complex, respectively, for 8 weeks. Throughout the 11-day duration of periodontitis induction, all rats were fed standard feed. The rats were euthanized on the eleventh day, and their tissue and blood samples were collected. In the periodontitis group, elevated tissue destruction parameters and reduced tissue formation parameters were found, as compared to the ASI groups. Levels of enzymes, cytokines, and mediators associated with periodontal tissue destruction were lower in rats fed a diet containing ASI complex after experimental periodontitis. These results indicate that ASI complex could be an alternative agent for host modulation.

Dietary arginine silicate inositol complex increased bone healing: histologic and histomorphometric study

Background

Arginine silicate inositol complex (ASI; arginine 49.5%, silicon 8.2%, and inositol 25%) is a novel material that is a bioavailable source of silicon and arginine. ASI offers potential benefits for vascular and bone health.

Objective

The aim of this study was to evaluate the potential effects of ASI complex on bone healing of critical-sized defects in rats.

Methods

The rats were randomly assigned to two groups of 21 rats each. The control group was fed a standard diet for 12 weeks; after the first 8 weeks, a calvarial critical-sized defect was created, and the rats were sacrificed 7, 14, and 28 days later. The ASI group was fed a diet containing 1.81 g/kg of ASI for 12 weeks; after the first 8 weeks, a calvarial critical-sized defect was created, and the rats were sacrificed 7, 14, and 28 days later. The calvarial bones of all the rats were then harvested for evaluation.

Results

Osteoblasts and osteoclasts were detected at higher levels in the ASI group compared with the control group at days 7, 14, and 28 of the calvarial defect (P<0.05). New bone formation was detected at higher levels in the ASI group compared with the controls at day 28 (P<0.05). However, new bone formation was not detected at days 7 and 14 in both the groups (P>0.05).

Conclusion

ASI supplementation significantly improved bone tissue healing in rats with critical-sized defects. This study demonstrated that ASI can enhance bone repair and has potential as a therapeutic regimen in humans.

A clinical evaluation to determine the safety, pharmacokinetics, and pharmacodynamics of an inositol-stabilized arginine silicate dietary supplement in healthy adult males

Purpose

The purpose of this study was to characterize the pharmacokinetics (PKs) and pharmacodynamics (PDs) of an oral inositol-stabilized arginine silicate dietary supplement.

Subjects and methods

Ten healthy males, 26.7±5.4 years, took three 500 mg arginine silicate capsules (active product) for 14 days. The subjects attended test visits on Days 1 and 14. Fasting blood and saliva collections were performed predose and at 0.5 hours, 1 hour, 1.5 hours, 2 hours, 3 hours, 4 hours, 5 hours, and 6 hours postdose for plasma arginine, serum silicon, and salivary nitric oxide (NO) + nitrite.

Results

Day 1 PK parameters (adjusted for body weight) for arginine were peak serum concentration (C_Max) 30.06±7.80 μg/mL, time it takes to reach peak serum concentration (t_Max) 1.13±0.52 hours, and time required to reach half its original concentration (t_1/2) 15.93±9.55 hours and for silicon were C_Max 2.99±0.63 μg/mL, t_Max 2.44±2.05 hours, and t_1/2 34.56±16.56 hours. After Day 1 dose, arginine levels increased at 0.5 hours, 1 hour, 1.5 hours, 2 hours, 3 hours, and 5 hours (P<0.01) and silicon levels increased at 1 hour and 1.5 hours (P<0.05). After Day 14 dose, arginine levels increased at 0.5 hours, 1 hour, and 1.5 hours (P<0.05) and silicon levels increased at 1 hour, 1.5 hours, 2 hours, and 3 hours (P<0.01). After 14 days of use, baseline arginine trended toward being higher than baseline Day 1 (P=0.0645), and 4-hour postdose plasma arginine was significantly higher (P=0.0488) at Day 14 than Day 1. Although not a significant difference, NO, as measured as salivary nitrate, increased in four subjects and stayed the same in six subjects at 0.5 hours after the first dose (P=0.125). After 14 days of use, baseline NO levels increased in six subjects and stayed the same in four subjects; this shift was significant (P=0.031).

Conclusion

The arginine silicate dietary supplement increases blood levels of arginine after a single dose within 30 minutes and blood levels of silicon for up to 1.5 hours. Blood levels of arginine, silicon, and NO (salivary nitrite) were elevated consistently after 14 days of use. The observed increase in baseline salivary nitrite is supporting information that there was some improvement in NO production. Further study on the effect of this supplement on NO production and the resulting physiological effect is warranted. Within the specific protocol of this study, the product was found to be safe.

A unique rodent model of cardiometabolic risk associated with the metabolic syndrome and polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is characterized by hyperandrogenism, oligo-/anovulation, and polycystic ovarian morphology and is a complex endocrine disorder that also presents with features of the metabolic syndrome, including obesity, insulin resistance, and dyslipidemia. These latter symptoms form cardiometabolic risk factors predisposing individuals to the development of type 2 diabetes and cardiovascular disease (CVD). To date, animal models to study PCOS in the context of the metabolic syndrome and CVD risk have been lacking. The aim of this study was to investigate the JCR:LA-cp rodent as an animal model of PCOS associated with the metabolic syndrome. Metabolic indices were measured at 6 and 12 wk, and reproductive parameters including ovarian morphology and estrous cyclicity were assessed at 12 wk or adulthood. At 6 wk of age, the cp/cp genotype of the JCR:LA-cp strain developed visceral obesity, insulin resistance, and dyslipidemia (hypertriglyceridemia and hypercholesterolemia) compared with control animals. Serum testosterone concentrations were not significantly different between groups at 6 wk of age. However, at 12 wk, the cp/cp genotype had higher serum testosterone concentrations, compared with control animals, and presented with oligoovulation, a decreased number of corpora lutea, and an increased number of total follicles, in particular atretic and cystic follicles. The cardiometabolic risk factors in the cp/cp animals were exacerbated at 12 wk including obesity, insulin resistance, and dyslipidemia. The results of this study demonstrate that the JCR:LA-cp rodent may be a useful PCOS-like model to study early mechanisms involved in the etiology of cardiometabolic risk factors in the context of both PCOS and the metabolic syndrome.

Evaluating micro- and macro-vascular disease, the end stage of atherosclerosis, in rat models

Development of effective treatment or, more critically, preventative measures against atherosclerosis and cardiovascular disease will require animal models that mimic the disease processes seen in humans and permit identification of the genetic and physiological factors. The Rat is normally resistant to cardiovascular disease, but a number of genetic mutations make affected strains of rats highly susceptible to atherosclerosis and micro- and macro-vascular disease that is highly analogous to human disease. These models of obesity develop the metabolic syndrome and type 2 diabetes, hyperinsulinemia, hyperlipidemia, vascular and myocardial dysfunction, and end-stage lesions in the heart and kidney. The models offer the prospect of both genetic and molecular biology studies that are linked directly to spontaneous cardiovascular disease and exploration of putative preventative or treatment approaches, including pharmaceutical agents. Use of small animal models of cardiovascular disease is dependent on appropriate experimental design and techniques that take account of the complex nature of the disease processes. Detailed experimental procedures for the use of rat models, including handling and treatment of animals, choice of experimental variables and endpoints, assay methods, and histological and electron microscopy techniques are covered in this chapter.

Pair feeding-mediated changes in metabolism: stress response and pathophysiology in insulin-resistant, atherosclerosis-prone JCR:LA-cp rats

Rats of the JCR:LA-cp strain, which are homozygous for the cp gene (cp/cp), are obese, insulin-resistant, and hyperinsulinemic. They exhibit associated micro- and macrovascular disease and end-stage ischemic myocardial lesions and are highly stress sensitive. We subjected male cp/cp rats to pair feeding (providing the rats each day with the amount of food eaten by matched freely fed animals), a procedure that alters the diurnal feeding pattern, leading to a state of intermittent caloric restriction. Effects on insulin, glucose, and lipid metabolism, response to restraint stress, aortic contractile/relaxant response, and myocardial lesion frequency were investigated. Pair-fed young (12-wk-old) cp/cp rats had lower insulin and glucose levels (basal and following restraint), consistent with increased insulin sensitivity, but a greater increase in plasma nonesterified fatty acids in response to restraint. These effects were unrelated to lipolytic rates in adipose tissue but may be related to reduced fatty acid oxidation in skeletal muscle. Older (24-wk-old) pair-fed cp/cp rats had significantly reduced plasma triglyceride levels, improved micro- and macrovascular function, and reduced severity of ischemic myocardial lesions. These changes indicate a significant amelioration of end-stage disease processes in this animal model and the complexity of metabolic/physiological responses in studies involving alterations in food intake. The effects illustrate the sensitivity of the JCR:LA-cp rat, an animal model for the metabolic syndrome and associated cardiovascular disease, to the environmental and experimental milieu. Similar stress-related mechanisms may play a role in metabolically induced cardiovascular disease in susceptible human beings.

Metabolic effects of a novel silicate inositol complex of the nitric oxide precursor arginine in the obese insulin-resistant JCR:LA-cp rat

Insulin resistance is a major contributor to macro- and microvascular complications, particularly in the presence of the metabolic syndrome, and is also associated with polycystic ovary syndrome. Impaired nitric oxide metabolism and endothelial function are important components of the vascular disease. Increasing the bioavailability of arginine, the precursor of nitric oxide, thus potentially offers protection against end-stage disease. We have recently demonstrated that dietary supplementation with a novel silicate inositol arginine complex reduces vasculopathy and glomerular sclerosis in the insulin-resistant JCR:LA-cp rat. The objective of this study was to address the absorption of, and the underlying metabolic alterations caused by, the arginine silicate inositol complex and arginine HCl (as a reference agent) in obese insulin-resistant male and female JCR:LA-cp rats. Male and female rats were treated with the preparations at 1.0 mg/(kg d) (expressed as arginine HCl) from 8 to 12 and 12 to 18 weeks of age, respectively. Obese female, but not male, rats treated with the arginine silicate inositol complex showed a reduced rate of weight gain without concomitant reduction in food intake. Plasma silicon levels were raised very significantly in arginine silicate-treated rats, consistent with significant absorption of the complex. In male rats, arginine levels were elevated by treatment with arginine silicate only; and female rats responded to both preparations. Plasma concentrations of oxides of nitrogen in rats treated with the silicate complex showed a dimorphism, decreasing in male and increasing in female rats. Fasting insulin levels were elevated in male rats treated with the arginine silicate complex, whereas fasting and postprandial insulin levels were decreased in female rats. Furthermore, female, but not male, rats treated with either of the arginine preparations showed significant reductions in cholesterol, triglyceride, and phospholipid concentrations. We conclude that the arginine silicate inositol complex is absorbed efficiently, raising plasma arginine levels, and is more biologically effective than the free amino acid hydrochloride. This has different beneficial metabolic effects in both sexes of an animal model of insulin resistance and cardiovascular disease, consistent with reduction in end-stage disease.

Increased insulin sensitivity and reduced micro and macro vascular disease induced by 2-deoxy-D-glucose during metabolic syndrome in obese JCR: LA-cp rats

BACKGROUND AND PURPOSE

The metabolic syndrome, characterized by obesity, insulin resistance and dyslipidemia, is a major cause of cardiovascular disease. The origins of the syndrome have been hypothesized to lie in continuous availability of energy dense foods in modern societies. In contrast, human physiology has evolved in an environment of sporadic food supply and frequent food deprivation. Intermittent food restriction in rats has previously been shown to lead to reduction of cardiovascular risk and a greater life span. The non-metabolizable glucose analogue, 2-deoxy-D-glucose (2-DG) is taken up by cells and induces pharmacological inhibition of metabolism of glucose. We hypothesized that intermittent inhibition of glucose metabolism, a metabolic deprivation, may mimic intermittent food deprivation and ameliorate metabolic and pathophysiological aspects of the metabolic syndrome.

EXPERIMENTAL APPROACH

Insulin resistant, atherosclerosis-prone JCR:LA-cp rats were treated with 2-DG (0.3% w/w in chow) on an intermittent schedule (2 days treated, one day non-treated, two days treated and two days non-treated) or continuously at a dose to give an equivalent averaged intake.

KEY RESULTS

Intermittent 2-DG-treatment improved insulin sensitivity, which correlated with increased adiponectin concentrations. Further, intermittent treatment (but not continuous treatment) reduced plasma levels of leptin and the inflammatory cytokine IL-1 beta. Both 2-DG treatments reduced micro-vascular glomerular sclerosis, but only the intermittent schedule improved macro-vascular dysfunction.

CONCLUSIONS AND IMPLICATIONS

Our findings are consistent with reduction in severity of the metabolic syndrome and protection against end stage micro- and macro-vascular disease through intermittent metabolic deprivation at a cellular level by inhibition of glucose oxidation with 2-DG.

Impaired postprandial apolipoprotein-B48 metabolism in the obese, insulin-resistant JCR:LA-cp rat: Increased atherogenicity for the metabolic syndrome

AIM

Postprandial lipaemia is a significant contributor to the development of dyslipidaemia and cardiovascular disease, which has more recently been shown as a potential risk factor for obesity and pre-diabetes. Clinically however, the diagnosis of early insulin-resistance remains confounded due to the fact that aberrations in lipid metabolism are not often readily identified using classic indicators of hypercholesterolemia (i.e. LDL).

METHODS

In this study, we assessed the metabolism of apolipoprotein-B48 (apoB48)-containing lipoproteins in an animal model of obesity and insulin-resistance, the JCR:LA-cp rat. The contribution of lipoproteins from the intestine was assessed by measuring plasma apoB48 concentration in the postprandial period following an oral fat load. Plasma apoB48 was measured by improved enhanced chemiluminescent detection and other biochemical parameters measured by established analysis.

RESULTS

Fasting concentrations of plasma apoB48, postprandial apoB48 area under the curve (AUC), as well as incremental-AUC (iAUC), were all significantly greater in the obese phenotype compared to lean controls. Fasting apoB48 correlated significantly with apoB48-iAUC, triglyceride (TG)-iAUC and insulin-iAUC. In addition, there was a highly significant association with fasting insulin and the postprandial ratio of TG:apoB48, a relationship not often detected in humans during insulin-resistance.

CONCLUSIONS/INTERPRETATION

We conclude that the JCR:LA-cp rat can be used as a model of postprandial lipemia to explore chylomicron metabolism during the onset and development of insulin-resistance, including the increased cardiovascular complications of the metabolic syndrome.

Synergistic effects of conjugated linoleic acid and chromium picolinate improve vascular function and renal pathophysiology in the insulin-resistant JCR:LA-cp rat

AIMS

Conjugated linoleic acid (CLA) is a natural constituent of dairy products, specific isomers of which have recently been found to have insulin sensitizing and possible antiobesity actions. Chromium is a micronutrient which, as the picolinate (CrP), has been shown to increase insulin sensitivity in animal models, including the JCR:LA-cp rat. We tested the hypothesis that these agents may have beneficial synergistic effects on the micro- and macrovasculopathy associated with hyperinsulinaemia and early type 2 diabetes.

METHODS

Insulin-resistant cp/cp rats of the JCR:LA-cp strain were treated with mixed isomers of CLA (1.5% w/w in the chow) and/or CrP at 80 microg/kg/day (expressed as Cr) from 4 weeks of age to 12 weeks of age. Plasma insulin, lipid and adiponectin levels, aortic vascular function, renal function and glomerular sclerosis were assessed.

RESULTS

CLA administration reduced food intake, body weight and fasting insulin in JCR:LA-cp rats. Plasma adiponectin levels were significantly elevated in rats treated with both CLA and CrP. Aortic hypercontractility was reduced and the relaxant response to the nitric oxide-releasing agent acetylcholine (Ach) was increased in CrP-treated rats. Striking reductions were also observed in the level of urinary albumin and the severity of glomerular sclerosis in rats treated specifically with CLA.

CONCLUSIONS

CLA and CrP have beneficial effects ameliorating several of the pathophysiologic features of an insulin-resistant rat model. These supplements may be useful adjuncts in the management of patients with the metabolic syndrome and warrant further study.

Dietary arginine silicate inositol complex during the late laying period of quail at different environmental temperatures

Arginine silicate inositol complex (ASIdagger; arginine 49.5%, silicon 8.2%, inositol 25%) is a novel material which is a bioavailable source of silicon and arginine. ASI offers potential benefits for vascular and bone health. Poor eggshell quality has been a major economic concern to commercial egg producers. Poor egg quality, skeletal abnormalities and architectural deterioration of bone tissue are common problems under hot conditions and in older birds. The effects of ASI supplementation on egg production, egg quality, levels of osteocalcin (OC) and bone mineral content were investigated in heat-stressed Japanese quail during the later part of the laying period. The birds were randomly assigned to six treatment groups consisting of six replicates of five birds each in a 2 x 3 factorial arrangement of treatments (temperatures, ASI levels). The birds were kept in wire cages in a temperature-controlled room at either 22 degrees C (TN) or 34 degrees C (HS) for 8 h/d and fed either a basal (control) diet or the basal diet supplemented with either 500 or 1000 g of ASI/kg. Heat exposure reduced egg production, egg quality and bone mineralisation when the basal diet was fed. ASI supplementation had no effect on feed intake or egg production under TN or HS conditions. However, ASI supplementation increased egg weight, shell thickness, shell weight and Haugh unit in both TN and HS groups during the late laying period. Bone mineral density (BMD) was significantly improved by ASI supplementation in both TN and HS groups. Serum osteocalcin (OC) concentrations and alkaline phosphatase (ALP) activity increased linearly with dietary ASI supplementation during the late laying period. The amount of calcium and phosphorus in the excreta decreased, while ash, mineral content, calcium and phosphorus concentrations in tibia increased in ASI-supplemented quail in both TN and HS groups during the late laying period. ASI supplementation significantly improved egg quality and bone mineralisation in quail during the late laying period and did not affect feed consumption or egg production.

Dietary arginine silicate inositol complex improves bone mineralization in quail

Skeletal abnormalities, low bone mass, bone deformities, and bone fractures increase the risk of osteoporosis and osteoarthritis, which are of concern from both a public standpoint and a cost-of-care burden standpoint. Arginine silicate inositol complex (ASI; Arg = 49.47%, silicone = 8.2%, inositol = 25%) is a novel, bioavailable source of Si and Arg and one that offers potential benefits for vascular and bone health. Skeletal abnormalities and architectural deterioration of bone tissue are common under hot climate conditions in the poultry industry. In this study, we evaluated the effects of ASI supplementation on performance and bone mineral density (BMD) in Japanese quail (Coturnix coturnix japonica) exposed to the high ambient temperature of 34 degrees C. The birds (n = 180; 10 d old) were randomly assigned to 6 treatment groups consisting of 10 replicates of 3 birds. Birds were kept in wire cages in a temperature-controlled room at either 22 degrees C (thermoneutral; TN) or 34 degrees C (heat stress; HS) for 8 h/d (0900 to 1700 h until the end of study) and were fed a basal (control) diet or the basal diet supplemented with either 500 or 1,000 mg of ASI/kg of diet. Heat exposure decreased performance and bone mineralization when the basal diet was fed (P = 0.001). The ASI supplement had no effect on feed intake, BW, feed efficiency, and carcass traits (P > 0.05) in quails reared under TN or HS conditions. The BMD was significantly improved by ASI supplementation in both TN and HS groups [0.72 (TN) vs. 0.60 (HS); P < or = 0.05]. Serum osteocalcin, dehydroepiandrosterone concentrations, and alkaline phosphatase activity increased, whereas tumor necrosis factor-alpha and Creactive protein concentrations decreased, as dietary ASI supplementation increased in quail reared under HS. This improvement was linear with increased doses of supplement (P = 0.001). In the ASI group, the amount of Ca, P, Mg, and Mn in the excreta decreased (P < or = 0.05), and the concentrations of these minerals in tibia ash increased in quail reared under HS conditions (P < or = 0.05). In conclusion, ASI supplementation to the basal diet significantly improved bone mineralization in quail and did not impact feed consumption, BW gain, or feed efficiency.

Hypersensitivity of Prediabetic JCR:LA-cp Rats to Fine Airborne Combustion Particle-Induced Direct and Noradrenergic-Mediated Vascular Contraction

Particulate matter with mean aerodynamic diameter < or =2.5 microm (PM(2.5)), from diesel exhaust, coal or residual oil burning, and from industrial plants, is a significant component of airborne pollution. Type 2 diabetes is associated with enhanced risk of adverse cardiovascular events following exposure to PM(2.5). Particle properties, sources, and pathophysiological mechanisms responsible are unknown. We studied effects of residual oil fly ash (ROFA) from a large U.S. powerplant on vascular function in a prediabetic, hyperinsulinemic model, the JCR:LA-cp rat. Residual oil fly ash leachate (ROFA-L) was studied using aortic rings from young-adult, obese, insulin-resistant rats and lean normal rats in vitro. Contractile response to phenylephrine and relaxant response to acetylcholine were determined in the presence and absence of L-NAME (N(G)-nitro-L-arginine methyl ester). In a separate series of studies, the direct contractile effects of ROFA-L on repeated exposure were determined. ROFA-L (12.5 microg ml(-1)) increased phenylephrine-mediated contraction in obese (p < 0.05), but not in lean rat aortae, with the effect being exacerbated by L-NAME, and it reduced acetylcholine-mediated relaxation of both obese and lean aortae (p < 0.0001). Initial exposure of aortae to ROFA-L caused a small contractile response (<0.05 g), which was markedly greater on second exposure in the obese (approximately 0.6 g, p < 0.0001) aortae but marginal in lean (approximately 0.1 g) aortae. Our data demonstrate that bioavailable constituents of oil combustion particles enhance noradrenergic-mediated vascular contraction, impair endothelium-mediated relaxation, and induce direct vasocontraction in prediabetic rats. These observations provide the first direct evidence of the causal properties of PM(2.5) and identify the pathophysiological role of the early prediabetic state in susceptibility to environmentally induced cardiovascular disease. These are important implications for public health and public policy.