AUDISTIM® Day/Night Alleviates Tinnitus-Related Handicap in Patients with Chronic Tinnitus: A Double-Blind Randomized Placebo-Controlled Trial

The aim of this study is to evaluate the efficacy of taking a daily supplement based on active compounds (AUDISTIM® Day Night: A D/N) in alleviating tinnitus-related disability, as suggested by previous real-life studies. This double-blind randomized placebo-controlled study was conducted in adults with mild to severe tinnitus receiving a 3-month supplementation with A D/N (magnesium, vitamins, phytochemicals) or placebo (excipients without active ingredients). Tinnitus-related handicap (THI), psychological stress (MSP-9), and sleep quality (PSQI) were assessed at baseline and during intervention, perceived impression of tinnitus improvement at the end of the follow-up. The full set analysis included 114 patients (59 A D/N, 55 placebo) aged 53.8 ± 11.4 years, 58% women, with fluctuating (45%) or permanent (55%) tinnitus from 9.3 ± 9.4 years. A D/N supplementation led to greater changes in THI (-13.2 ± 16.0 vs. -6.2 ± 14.4, p = 0.0158,Cohen's d =0.44) at 3 months (primary outcome), especially with continuous tinnitus (-15.0 ± 16.3 vs. -4.6 ± 12.8, p = 0.0065), and, to a lesser extent, at 1 month (-9.8 ± 13.1 for A vs. -4.3 ± 12.1, p = 0.0213). PSQI significantly improved over time in both groups, but MSP-9 only with A D/N. In lines with previous observational studies, both clinical (THI score > 7 pts) and statistical (vs. placebo) improvement, more pronounced in permanent tinnitus, demonstrate the effectiveness of the combination of active compounds and support its use in the management of mild to severe tinnitus.

Probiotics plus vitamin D in irritable bowel syndrome: a prospective multicentric non-interventional study

BACKGROUND

Patients with irritable bowel syndrome (IBS) experience recurrent symptoms and anxiety disorders that significantly impact their quality of life (QoL). The aim of the study was to assess in daily practice the benefit of the combination of three probiotic strains (Lactobacillus plantarum CETC 7484 and CETC 7485; Pediococcus acidilactici CECT 7483) plus vitamin D in patients with diarrhea-predominant IBS (IBS-D) or IBS with mixed bowel movements (IBS-M).

METHODS

This was a prospective, multicenter, non-interventional study in adult patients with IBS-D or IBS-M (Rome IV criteria) followed by private-practice gastroenterologists. Patients received daily one sachet of a combination of probiotics (3×109 CFU) and vitamin D (10 μg) for 42 days. The primary endpoint was the responder rate at D42 (≥50% and/or ≥100-point decrease of IBS-Severity Scoring System; IBS-SSS). Gut-related anxiety was measured with the Visceral Sensitivity Index (VSI).

RESULTS

The full analysis set population included 246 patients (mean age, 51.2±15.4 years; women, 73.2%; IBS-D, 56.1%; IBS-M, 43.9%). At D42, among the 89 patients with evaluable data, the responder rate was 62.9% with a mean decrease of IBS-SSS of 146.6±125.9 (P<0.0001). Changes of IBS-SSS were significantly correlated with changes of IBS-QoL (r=-0.78; P<0.0001), HAD-anxiety (r=0.46; P<0.0001), HAD-depression (r=0.61; P<0.001) and VSI (r=0.74; P<0.0001).

CONCLUSIONS

These real-life results are in line with a previous randomized clinical trial demonstrating the benefits of this combination in IBS-D and IBS-M. Symptom relief was associated with improvement of IBS-QoL, anxiety, depression and specifically gut-related anxiety.

The Observatoire en Ville des Plaies ExSudatives (VIPES) study: insight into the patient characteristics, epidemiology, previous management, and features of wounds treated in the French community setting

BACKGROUND

Wounds that become complex and hard-to-heal are a challenge for all health care systems. Identifying and understanding the nature of these wounds is necessary to allow appropriate intervention.

OBJECTIVE

To present the epidemiological outcomes of the VIPES study.

MATERIALS AND METHODS

The prospective, observational VIPES study aimed to describe the use and investigate the performance of 2 wound dressings-a silicone foam and a gelling fiber-in the management of chronic and acute wounds in a community setting in France.

RESULTS

Of 407 patients recorded, 285 were included in the analysis. The 184 chronic wounds included ulcers (venous/arterial/mixed, diabetic foot, and pressure) and malignant wounds. The 101 acute wounds included surgical and traumatic wounds. Of all wounds, 98.2% were exuding and 77.9% showed exudate pooling. Unhealthy wound edges and periwound skin were reported in 57.2% and 35.4% of wounds, respectively. Of all wounds, 78.6% were in treatment failure (poor exudate management or stagnant wound). The silicone foam dressing (n = 86) and the gelling fiber (n = 199) were generally used in wounds with low or moderate exudation, or moderate or high exudation, respectively.

CONCLUSIONS

The VIPES study highlights that wounds can be complex and that community care practices in France warrant improvement. Practical and up-to-date wound management recommendations are needed.

Gastrointestinal Tolerance of Short-Chain Fructo-Oligosaccharides from Sugar Beet: An Observational, Connected, Dose-Ranging Study in Healthy Volunteers

Dietary fibres are important in the human diet with multiple health benefits. This study aimed to determine the gastrointestinal tolerance of short-chain fructo-oligosaccharides (scFOS), well-known prebiotic fibres, at doses up to 40 g/d. An observational, connected, dose-ranging trial was conducted in 116 healthy volunteers. During the first week, the participants were instructed to consume their usual diet. During the second week, half of the subjects consumed 15 g scFOS per day, and the other half consumed 20 g scFOS per day. For the third week, the scFOS dose was doubled for all subjects. Gastrointestinal symptom severity was reported daily, as well as stool consistency and frequency. The results show that scFOS are well tolerated up to 40 g/d; all reported symptoms remained very mild from a clinical perspective. Stool consistency stayed normal, between 3 and 5 on the Bristol stool scale, confirming that no diarrhoea appeared after scFOS intake. Stool frequency also remained within the normal range. In conclusion, scFOS intake is well tolerated up to 40 g/d in healthy subjects. Thanks to their short chains and unique composition, scFOS prebiotic fibres are much better tolerated than other types of inulin-type fructans with longer chains. The digestive tolerance of fibres should be considered when added to foods and beverages.

The clinical impact of hydro-responsive dressings in dynamic wound healing: Part II

OBJECTIVE

Over the course of a wound's healing trajectory, whether the wound is acute or hard-to-heal, management is likely to involve the use of several different dressing types. Minimising the complexity of treatment (in terms of dressing usage) would aid clinicians in providing effective wound care but excellent clinical outcomes must remain the primary goal.

METHOD

This study was an open-labelled, non-comparative study assessing the clinical effectiveness of a coordinated wound dressing treatment regimen. After an initial phase of using a hydro-responsive wound dressing (HydroClean, HRWD-1, PAUL HARTMANN AG, Germany) to cleanse and debride hard-to-heal wounds, the wounds were subsequently treated with either HydroTac (HRWD-2, PAUL HARTMANN AG, Germany) (to maintain healing progression and re-epithelialisation) or RespoSorb (a superabsorbent dressing, PAUL HARTMANN AG, Germany) (to manage moderate-to-high levels of exudate). The Pressure Ulcer Scale for Healing (PUSH) assessment tool was used to measure the wound status over the course of the treatment period and to assess several wound status parameters (for example, wound area, exudate levels and wound characteristics such as level of re-epithelialisation).

RESULTS

The results from this study demonstrated that wounds treated with HRWD-2 showed a positive healing response when using the PUSH score assessment tool with a significant mean reduction (p<0.0001) in the PUSH score of wounds treated with HRWD-2, with >75% of wounds being closed by the end of the study. This result underlines the effectiveness of HRWD-2 in supporting healing progression.

CONCLUSION

The results from this study support the coordinated use of HRWDs for the effective management and treatment of a variety of hard-to-heal wounds.

The clinical impact of hydroresponsive dressings in dynamic wound healing: Part I

OBJECTIVE

Management of any wound, either acute or hard-to-heal, might involve the use of multiple and different wound dressings in its treatment. This approach is necessary to overcome the myriad of clinical challenges the wound presents, as well as any underlying comorbidities that might affect the clinical outcomes. This article describes the clinical effectiveness of a coordinated wound dressing treatment regimen.

METHOD

This was an open-labelled non-comparative study involving patients with a variety of hard-to-heal and acute wounds of differing levels of severity, but all of which required removal of devitalised tissue to enable wound healing to progress. The first phase used the hydroresponsive wound dressing HydroClean (PAUL HARTMANN AG, Germany). The PUSH score was used as the primary measurement parameter.

RESULTS

A total of 86 patients (38 male/48 female), with a mean age of 67.7±21.7 years, took part in the study. The results showed that the hydroresponsive dressing was effective in managing wound exudate production and promoting wound cleansing and debridement, supporting good wound bed preparation. Wound closure was observed in 16/86 (18.6%) wounds at the end of the study (20 weeks). This enabled clinicians to switch to alternative wound dressings to promote subsequent clinical healing outcomes.

CONCLUSION

In this study, the hydroresponsive wound dressing was highly effective in preparing a clean wound bed such that the next stage of wound healing could be supported.

Food grade lingonberry extract: polyphenolic composition and in vivo protective effect against oxidative stress

Fractionation of the polyphenols constituting a food grade lingonberry extract (Vaccinium vitis-idaea) highlighted a composition more complex than described until now in the berry. Procyanidins B1, B2, and A2 were identified by UPLC/ESI-MS(2) along with the presence of other flavanol oligomers. Processing induced the release of large amounts of aglycones for ferulic acid, p-coumaric acid, and quercetin. The described anthocyanic composition of lingonberry was completed with hexoside derivatives of peonidin, petunidin, malvidin, and delphinidin. Besides confirmation of in vitro antioxidant activity, in vivo study was performed on rats fed a diet inducing oxidative stress. Supplementation with lingonberry extract significantly decreased the total oxidant status and favorably affected antioxidant defense enzymes in red blood cells and liver. A drop in the serum reduced glutathione level was also prevented, and uric acid was maintained at low level, confirming the antioxidant activity of the extract (5% proanthocyanidins) from a dosage of 23 mg/kg of body weight.

Cholesterol-lowering effect of non-viscous soluble dietary fiber Nutriose6 in moderately hypercholesterolemic hamsters

NUTRIOSE6 is a new wheat starch-based low-digestible carbohydrate. This study investigated the effect of this soluble non-viscous fiber on cholesterol metabolism. Hamsters fed with 0.25% cholesterol-enriched diet (CHO) were given graded amounts of NUTRIOSE6, i.e., 0% (cellulose, CHO), 3% (N3), 6% (N6) or 9% (N9) (w:w). As compared to CHO diet, 9% NUTRIOSE6 significantly lowered plasma and LDL cholesterol by 14.5 and 23.8%, respectively. The LDL-cholesterol lowering effect was also significant with the 6% dose (-21.4%). NUTRIOSE6 diets prevented hepatic cholesterol accumulation (-10 to -20%) and significantly decreased bile cholesterol (-47 to -68%) and phospholipids (-30 to -45%) concentrations. The 9% NUTRIOSE6 diet significantly decreased the rate of dietary cholesterol absorption (-25%) and markedly stimulated faecal neutral sterol (+81%) and bile salts (+220%) excretion. No significant change in cholesterol 7-alpha-hydroxylase or LDL-receptor activities was observed whereas 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity was reduced by 29%. Reduced cholesterol and bile salt absorptions and lowered cholesterol synthesis are likely mechanisms underlying the cholesterol lowering effect of NUTRIOSE6. Results suggest the use of NUTRIOSE6 as a new dietary cholesterol-lowering agent that should be tested in humans as treatment and evenly prevention of mild hypercholesterolemia.

Grape extract improves antioxidant status and physical performance in elite male athletes

Excessive physical exercise overproduces reactive oxygen species. Even if elite sportsmen increase their antioxidant status by regular physical training, during the competition period, this improvement is not sufficient to limit free radical production which could be detrimental to the body. The aim of this randomized, double-blind, placebo controlled, and crossover study on 20 elite sportsmen (handball = 10, basketball = 5, sprint = 4, and volleyball = 1) during the competition period was to determine if the consumption of a grape extract (GE; Vitis vinifera L.) was able to improve the parameters related to (i) anti-oxidative status and oxidative stress and (ii) physical performance. Specific biomarkers of antioxidant capacity, oxidative stress, skeletal cell muscle damage, and other general biomarkers were determined in plasma and urine before (D0) and after one month (D30) of placebo or GE supplementation (400mg·d(-1)). Effort tests were conducted using the Optojump(®) system, which allows determining the total physical performance (EnRJ45), explosive power (RJ110), and fatigue (RJL5). The plasma ORAC value was not modified in the placebo group; however, GE increased the ORAC value compared to the placebo at D30 (14 966+/-335 vs 14 242+/-339 dµmol Teq·L(-1); p < 0.05). The plasma FRAP value was significantly reduced in the placebo group, but not in the GE group. Therefore, GE limited the reduction of FRAP compared to the placebo at D30 (1 053.7+/-31.5 vs 993.7+/-26.7 µmol Teq·L(-1); p < 0.05). Urinary isoprostane values were increased in the placebo group, but were not modified in the GE group. Consequently, GE limited the production of isoprostanes compared to the placebo at D30 (1.24+/-0.12 vs 1.26+/-0.13 ng·mg(-1) creatinine; p < 0.05). GE administration, compared to the placebo at D30, reduced the plasmatic creatine phosphokinase concentration (CPK, 695.7+/-177.0 vs 480.0+/-81.1 IU·L(-1), p = 0.1) and increased hemoglobin levels (Hb, 14.5+/-0.2 vs 14.8+/-0.2 vs g·dL(-1), p < 0.05), suggesting that GE administration might protect cell damage during exercise. The high variability between sport disciplines did not permit to observe the differences in the effort test. Analyzing each individual group, handball players increased their physical performance by 24% (p < 0.05) and explosive power by 6.4% (p = 0.1) after GE supplementation compared to the placebo. Further analyses showed that CPK and Hb were the only biomarkers correlated with the increase in performance. In conclusion, GE ameliorates the oxidative stress/antioxidant status balance in elite athletes in the competition period, and enhances performance in one category of sportsmen (handball). Our results suggest that the enhancement in performance might be caused by the protective action of GE during physical exercise. These findings encourage conducting further studies to confirm the efficacy and mechanisms of action of GE on elite and occasional athletes. Key pointsGrape extract consumption improves the oxidative stress/antioxidant status balance in sportsmen.Grape extract consumption enhances physical performance in one category of sportsmen (Handball).The performance enhancement might be caused by the protective action of grape extract during physical exercise.

Differential effect of dietary antioxidant classes (carotenoids, polyphenols, vitamins C and E) on lutein absorption

Lutein is assumed to protect the human retina from blue light and oxidative stress and diminish the incidence of age-related macular degeneration. This antioxidant is commonly ingested with other dietary antioxidants. The aim of the present study was to assess whether the main dietary antioxidants, i.e. carotenoids, polyphenols and vitamins C and E, affect lutein absorption. We measured the effect of adding a mixture of antioxidants (500 mg vitamin C, 67 mg (100 IU) vitamin E and 1 g polyphenols) to a lutein-containing meal (18 mg) on the postprandial lutein response in the chylomicron-rich fraction in eight healthy men. Lutein response was weakest ( − 23 %;P = 0·07) after ingestion of the meal containing antioxidants (21·9 (sem4·6)v.28·4 (sem7·2) nmol × h/l). To assess the effect of each class of antioxidants and potential interactions, we subsequently evaluated the effect of various combinations of antioxidants on lutein uptake by human intestinal Caco-2 TC-7 cells. A full factorial design showed that both a mixture of polyphenols (gallic acid, caffeic acid, (+)-catechin and naringenin) and a mixture of carotenoids (lycopene plus β-carotene) significantly (P < 0·05) impaired lutein uptake by ( − 10 to − 30 %), while vitamins C and E had no significant effect. Subsequent experiments showed that the aglycone flavanone naringenin was the only polyphenol responsible for the effect of the polyphenol mixture, and that the carotenoid effect was not carotenoid species-dependent. Taken together, the present results suggest that lutein absorption is not markedly affected by physiological concentrations of vitamins C and E but can be impaired by carotenoids and naringenin.

Prevention of diet-induced fatty liver in experimental animals by the oral administration of a fatty acid bile acid conjugate (FABAC)

Fatty acid bile acid conjugates (FABACs) are a new family of synthetic molecules designed to solubilize biliary cholesterol. They were shown to prevent and dissolve cholesterol gallstones in inbred C57L/J mice fed a lithogenic, high-fat diet (HFD). In these mice, fatty liver was observed in the controls but not in the FABAC-treated ones. The present study was designed to study the effect of FABAC (arachidyl-amido-cholanoic acid) on diet-induced fatty liver in rats, hamsters, and mice. The fatty liver score (on a scale of 0-4 by light microscopy) was 4.0 in control hamsters and 0.3 in the FABAC-fed hamsters (P <.001). In mice it was 1.5 and 0.4, respectively (P <.01). The lipid/protein ratio in the liver was 1.3 +/- 0.44 (mg lipid/mg protein) in control rats and 0.66 +/- 0.04 in the FABAC group (P =.001) after 14 days. In hamsters it was 1.41 +/- 0.27 and 1.11 +/- 0.20, respectively (P =.03), after 21 days. In Imperial Charles River (ICR) mice the ratio was 0.34 +/- 0.10 and 0.17 +/- 0.07 (P =.03), respectively, after 24 days. Liver fat concentration, measured as mg lipid/g liver tissue, decreased similarly by FABAC feeding. The decrease in liver fat affected mainly the triglyceride levels. FABAC-fed animals gained weight similarly to the controls. Triglyceride absorption was unaffected by FABAC supplementation. In conclusion, oral FABAC therapy prevents/reduces the development of fatty liver in animals consuming a HFD.

Inhibitory effect of the pancreatic lipase C-terminal domain on intestinal lipolysis in rats fed a high-fat diet: chronic study

OBJECTIVE

Previous in vitro experiments, as well as acute assays in rat showed that the C-terminal domain (CT-domain) of porcine pancreatic lipase behaves as a potent specific noncovalent inhibitor of pancreatic lipase. Nevertheless, the potential use of the CT-domain as a therapeutic tool against obesity in humans requires further investigation and would be best achieved using the human CT-domain. In the present study, we investigated the inhibitory effects of the recombinant human CT-domain, in vivo, upon chronic administration to rats fed a high-fat diet.

DESIGN AND MEASUREMENT

The long-term in vivo study requiring relatively high amounts of the human CT-domain, the domain was overexpressed in Escherichia coli as inclusion bodies and an efficient refolding protocol was designed. The inhibitory effect of the recombinant human CT-domain on the activity of pancreatic lipase from different species was first investigated in vitro. Then chronic assays were performed for 4 weeks in rats fed a high-fat diet with or without a daily dose of 1.2 mg of CT-domain per kilogram rat. The time course of food intake, body weight, plasma parameters, liver lipids, faecal output of fat and total cholesterol were measured.

RESULTS

A high yield of correctly folded recombinant human CT-domain was obtained using our refolding process, as evidenced by the capability of the recombinant domain to inhibit human horse and porcine pancreatic lipases in vitro. The recombinant human CT-domain had no influence on the food intake, but significantly reduced the body weight gain. As compared to control rats, higher amounts of total fat (mainly triglycerides and monoglycerides) and total cholesterol were found in the faeces of the rats treated with the CT-domain. Finally, a decrease in liver triglycerides and nonesterified cholesterol was observed while no significant effect could be detected on the plasma parameters.

CONCLUSIONS

These results demonstrated that the CT-domain efficiently reduces in vivo, lipolysis and subsequently body weight gain in rat fed a high-fat diet. The CT-domain could, therefore, be effective in preventing obesity.

Butter differs from olive oil and sunflower oil in its effects on postprandial lipemia and triacylglycerol-rich lipoproteins after single mixed meals in healthy young men

Accumulation of postprandial triacylglycerol-rich lipoproteins is generated by assimilation of ingested dietary fat and has been increasingly related to atherogenic risk. Nevertheless, the influence of different kinds of dietary fatty acids on postprandial lipid metabolism is not well established, except for (n-3) polyunsaturated long-chain fatty acids. Our goal was to evaluate the effects of test meals containing a common edible fat source of saturated (butter), monounsaturated (olive oil) or (n-6) polyunsaturated (sunflower oil) fatty acids on postprandial lipid and triacylglycerol-rich lipoprotein responses. After a 12-h fast, 10 healthy young men ingested mixed meals containing 0 g (control) or 40 g fat, provided as butter, olive oil or sunflower oil in a random order. Fasting and postmeal blood samples were collected for 7 h. The no-fat test meal did not elicit any change over baseline except for plasma phospholipids, insulin and nonesterified fatty acids. Conversely, the three fat-containing meals elicited bell-shaped postprandial changes (P < 0.05) in serum triacylglycerols, free and esterified cholesterol, and nonesterified fatty acids. The butter meal induced a lower postprandial rise of triacylglycerols in serum and chylomicrons (incremental AUC, mmol.h/L: 0.72) than the two unsaturated oils (olive oil: 1.6, sunflower oil: 1.8), which did not differ. Circulating chylomicrons were smaller after the butter meal than after the two vegetable oil meals. The in vitro susceptibility of circulating chylomicrons to hydrolysis by postheparin plasma was higher after sunflower oil than after butter or olive oil. We conclude that butter results in lower postprandial lipemia and chylomicron accumulation in the circulation of young men than olive or sunflower oils after consumption of a single mixed meal.

Mechanisms of inhibition of triacylglycerol hydrolysis by human gastric lipase

In the human stomach, gastric lipase hydrolyzes only 10 to 30% of ingested triacylglycerols because of an inhibition process induced by the long chain free fatty acids generated, which are mostly protonated at gastric pH. The aim of this work was to elucidate the mechanisms by which free fatty acids inhibit further hydrolysis. In vitro experiments examined gastric lipolysis of differently sized phospholipid-triolein emulsions by human gastric juice or purified human gastric lipase, under close to physiological conditions. The lipolysis process was further investigated by scanning electron microscopy, and gastric lipase and free fatty acid movement during lipolysis were followed by fluorescence microscopy. The results demonstrate that: 1) free fatty acids generated during lipolysis partition between the surface and core of lipid droplets with a molar phase distribution coefficient of 7.4 at pH 5.40; 2) the long chain free fatty acids have an inhibitory effect only when generated during lipolysis; 3) inhibition of gastric lipolysis can be delayed by the use of lipid emulsions composed of small-size lipid droplets; 4) the release of free fatty acids during lipolysis induces a marked increase in droplet surface area, leading to the formation of novel particles at the lipid droplet surface; and 5) the gastric lipase is trapped in these free fatty acid-rich particles during their formation. In conclusion, we propose a model in which the sequential physicochemical events occurring during gastric lipolysis lead to the inhibition of further triacylglycerol lipolysis.

Acute hyperinsulinism modulates plasma apolipoprotein B-48 triglyceride-rich lipoproteins in healthy subjects during the postprandial period

The role of postprandial insulin in the regulation of postprandial lipid metabolism is still poorly understood. The roles of hyperinsulinemia and insulin resistance in the alteration of postprandial lipid metabolism are not clear either. To improve knowledge in this area, we submitted healthy men to acute hyperinsulinemia in two different ways. In the first study, we compared in 10 men the effects of four isolipidic test meals that induce different degrees of hyperinsulinemia on postprandial lipid metabolism. Three different carbohydrate sources were compared according to their glycemic indexes (GIs; 35, 75, and 100 for white kidney bean, spaghetti, and white bread test meals, respectively); the fourth test meal did not contain any carbohydrates. Postprandial plasma insulin levels were proportional to the GIs (maximal plasma insulin concentrations: 113 +/- 16 to 266 +/- 36 pmol/l). We found a strong positive correlation during the 6-h postprandial period between apolipoprotein (apo) B-48 plasma concentration and insulin plasma concentration (r2 = 0.70; P = 0.0001). In a second study, 5 of the 10 subjects again ingested the carbohydrate-free meal, but during a 3-h hyperinsulinemic- (550 +/- 145 pmol/l plasma insulin) euglycemic (5.5 +/- 0.8 mmol/l plasma glucose) clamp. A biphasic response was observed with markedly reduced levels of plasma apoB-48 during insulin infusion, followed by a late accumulation of plasma apoB-48 and triglycerides. Overall, the data obtained showed that portal and peripheral hyperinsulinism delays and exacerbates postprandial accumulation of intestinally derived chylomicrons in plasma and thus is involved in the regulation of apoB-48-triglyceride-rich lipoprotein metabolism, in the absence of insulin-resistance syndrome.

Determination of apolipoprotein B-48 in plasma by a competitive ELISA

BACKGROUND

Apolipoprotein B-48 (apoB-48) is produced by the small intestine, as part of chylomicrons, and appears to be a suitable marker for clinical studies of postprandial lipoproteins and related cardiovascular risk. Our aim was to develop, for routine analysis, an assay to quantify apoB-48 in plasma samples.

METHODS

A microtiter plate was coated with a C-terminal apoB-48-specific heptapeptide. Plasma samples were incubated with appropriate detergent to allow competition between immobilized antigen and plasma apoB-48. Appropriate calibration curves were obtained in the ELISA, using calibrated lymph and chylomicrons.

RESULTS

Treatment of plasma samples with the mild detergent Triton X-100 allowed an efficient competition between immobilized antigen and plasma apoB-48. No cross-reactivity was found with apoB-100, as checked by ELISA and Western blot analysis. Intra- and interassay CVs were 5.4% and 5. 5%, respectively. In healthy subjects, apoB-48 concentrations markedly increased in the postprandial state, in parallel with triglycerides.

CONCLUSIONS

This new ELISA allows determination of the concentration of apoB-48 in normolipidemic plasma.

Determination of Apolipoprotein B-48 in Plasma by a Competitive ELISA

Background: Apolipoprotein B-48 (apoB-48) is produced by the small intestine, as part of chylomicrons, and appears to be a suitable marker for clinical studies of postprandial lipoproteins and related cardiovascular risk. Our aim was to develop, for routine analysis, an assay to quantify apoB-48 in plasma samples.

Methods: A microtiter plate was coated with a C-terminal apoB-48-specific heptapeptide. Plasma samples were incubated with appropriate detergent to allow competition between immobilized antigen and plasma apoB-48. Appropriate calibration curves were obtained in the ELISA, using calibrated lymph and chylomicrons.

Results: Treatment of plasma samples with the mild detergent Triton X-100 allowed an efficient competition between immobilized antigen and plasma apoB-48. No cross-reactivity was found with apoB-100, as checked by ELISA and Western blot analysis. Intra- and interassay CVs were 5.4% and 5.5%, respectively. In healthy subjects, apoB-48 concentrations markedly increased in the postprandial state, in parallel with triglycerides.

Conclusions: This new ELISA allows determination of the concentration of apoB-48 in normolipidemic plasma.

Chronically gorging v. nibbling fat and cholesterol increases postprandial lipaemia and atheroma deposition in the New Zealand white rabbit

In the present study, we compared the effects of nibbling and gorging on postprandial lipaemia and lipoproteins, hepatic lipid uptake and atheroma deposition. New Zealand White rabbits were fed on a low-fat (LF) control diet or a peanut oil- (10 g/d) and cholesterol- (0.5 g/d) enriched (HF) diet with the fat and cholesterol components given either by nibbling (HF-N) or gorging (HF-G). After 4 and 8 weeks, rabbits were given a test meal, which was either nibbled or taken as a bolus. The LF diet did not noticeably alter postprantial lipid variables. Triacylglycerol levels, 0-35 h lipid responses and plasma accumulation of dietary lipids were significantly higher in the HF-G group than in the HF-N group, despite higher post-heparin plasma lipase activities. Furthermore, as studied on cultured isolated hepatocytes, the higher the rate of supply of triacylglycerol- and cholesterol-rich lipoproteins (TCRL), the lower the rate of lipid uptake and bile salt secretion. Atheroma deposition was significantly increased by gorging the HF diet and was correlated with levels of most postprandial lipid variables. We conclude that gorging v. nibbling a fat and cholesterol-enriched diet exacerbates postprandial lipaemia by reducing the rate of TCRL clearance and favours atheroma deposition.

Green tea extract (AR25®) inhibits lipolysis of triglycerides in gastric and duodenal medium in vitro

In this study, we aimed to evaluate in vitro the inhibitory activity of a green tea extract (AR25 standardized at 25% catechins) on gastric and pancreatic lipase activities. We first used tributyrin as a substrate to evaluate the capability of AR25 to induce digestive lipase inhibition. Gastric lipase was totally inhibited by 40 mg AR25/g tributyrin whereas pancreatic lipase inhibition was maximum (78.8 +/- 0.7%) with 80 mg AR25/g tributyrin. We then used triolein, a long-chain triglyceride, to check whether AR25 could alter lipase activities on a physiologic substrate. AR25 60 mg/g triolein induced a dramatic inhibition of gastric lipase (96.8 +/- 0.4%) whereas pancreatic lipase activity was partially reduced (66.50 +/- 0.92%). Finally, the concerted action of gastric and pancreatic lipases was studied with an excess of enzymes to mimic the physiologic conditions observed in vivo. Incubation of AR25 with an excess of digestive lipases resulted in a drastic decrease in gastric lipolysis but the inhibitory effect on pancreatic lipase was less marked. On the whole, as compared to the control, lipolysis of triolein under the successive action of the two digestive lipases was reduced by 37 +/- 0.6% in the presence of AR25. Because a lipid/water interface is necessary for lipolysis to occur, lipid emulsification and emulsion droplet size were measured in gastric and duodenal media in the presence of AR25. In gastric and duodenal conditions, AR25 inhibited the lipid emulsification process. From these data we conclude that (1) in vitro, fat digestion is significantly inhibited by 60 mg AR25/g triolein, and (2) gastric as well as pancreatic lipase inhibition could be related to altered lipid emulsification in gastric or duodenal media. The green tea extract AR25 exhibiting marked inhibition of digestive lipases in vitro is likely to reduce fat digestion in humans.

Acute ingestion of different dietary fatty acid species modulates postprandial lipid responses in New Zealand white rabbits

Although several investigations have linked the degree of fatty acid saturation to plasma lipid responses in the postprandial state, further evaluation is necessary. In this study, we compared the effect of saturated (SFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fatty acids on postprandial lipid metabolism using complementary in vivo and in vitro approaches. Fat (10 g) cholesterol (0.5 g) test meals that provided either lard (SFA), olive oil (MUFA), or sunflower oil (PUFA) were ingested by chow-fed New Zealand white rabbits (n = 8). In addition, hepatic uptake of triglyceride-cholesterol-rich lipoproteins (TCRL) isolated from rabbits chronically ingesting SFA, MUFA, or PUFA diets was measured using freshly isolated chow-fed rabbit hepatocytes. Whatever dietary fatty acids ingested, postprandial triglyceridemia and occurrence of radiolabelled dietary lipids in plasma were not markedly different. Conversely, SFA induced higher postprandial cholesterolemia and phospholipemia than MUFA (P < 0.05) whereas PUFA prevented postprandial cholesterol increase. TCRL disappearance from cultured liver cell media was delayed with SFA-rich TCRL and faster with PUFA whereas MUFA-rich TCRL showed an intermediate figure. From these data, we conclude that SFA, MUFA, and PUFA elicited different postprandial plasma and lipoprotein lipid responses. The fatty acid composition of TCRL had a major impact on their subsequent metabolism, especially uptake by cultured hepatocytes. The SFA-induced hypercholesterolemia could be related to an altered hepatic uptake whereas a faster clearance and hepatic uptake could explain the cholesterol-lowering effect of PUFA in rabbits. MUFA, like PUFA, accelerate uptake by hepatocytes but favor cholesterol ester enrichment of TCRL.

Influence of obesity and body fat distribution on postprandial lipemia and triglyceride-rich lipoproteins in adult women

We know that upper body obesity is associated with metabolic complications, but we don't know how regional body fat distribution influences postprandial lipemia in obese adults. Thus, this study explored the respective effects of android or gynoid types of obesity and fasting triglyceridemia on postprandial lipid metabolism and especially triglyceride-rich lipoproteins. Twenty-four obese and 6 lean normotriglyceridemic women (control), age 24-57 yr, were enrolled. Among obese women with an android phenotype, 9 exhibited normal plasma triglyceride levels (mean: 1.38 mmol/L) (NTAO), and 7 displayed a frank hypertriglyceridemia (mean: 2.40 mmol/L) (HTAO). The 8 patients with a gynoid phenotype had normal triglyceride levels (mean: 1.00 mmol/L) (GO). All were given a mixed test meal providing 40 g triglycerides. Serum and incremental chylomicron triglycerides 0-7 h areas under the curve (AUCs) as well as triglyceride levels in apoB-48-containing triglyceride-rich lipoprotein (TRLs) or chylomicrons were significantly higher in HTAOs and NTAOs than in GOs and controls postprandially. The size of chylomicron particles was bigger in controls and GOs than in HTAOs and NTAOs postprandially. Android obese subjects showed abnormally elevated fasting apoB-48 and apoB-100 triglyceride-rich lipoprotein (TRL) levels. Most abnormalities that were found correlated to plasma levels of insulin and apoC-III. In conclusion, an abnormal postprandial lipid pattern is a trait of abdominal obesity even without fasting hypertriglyceridemia.

Effects of graded amounts (0-50 g) of dietary fat on postprandial lipemia and lipoproteins in normolipidemic adults

Eight normolipidemic males ingested on separate days and in a random order five mixed meals containing 0, 15, 30, 40, or 50 g fat. Fasting and postprandial blood samples were obtained for 7 h and chylomicrons and lipoproteins were isolated. The nonfat and 15-g fat meals did not generate noticeable postprandial variations except for HDL phospholipids (P < 0.05). The serum and chylomicron triacylglycerol responses obtained after the meals correlated positively with the amount of fat ingested and peaked after 2-3 h. Serum free cholesterol and phospholipids increased and esterified cholesterol decreased postprandially in a dose-response manner. At the same time, triacylglycerol-rich-lipoprotein triacylglycerols, esterified cholesterol, LDL free cholesterol, HDL triacylglycerols, phospholipids, and free cholesterol increased whereas LDL and HDL esterified cholesterol decreased when the amount of ingested fat increased. The data showed that increasing the amount of fat in the usual range of ingestion (0-50 g) led to stepwise increases in the postprandial rise of chylomicron and serum triacylglycerols and induced marked changes in serum lipoproteins postprandially. The existence of a no-effect level of dietary fat (15 g) on postprandial lipemia and lipoproteins in healthy adults was shown.

Postprandial lipaemia is exacerbated in fat-cholesterol-fed rabbits: relationship to atheroma deposition

The aim of the present study was to evaluate the links between chronic fat-cholesterol intake, postprandial lipaemia and atherogenesis in New Zealand White rabbits. Adult rabbits were fed on either a low-fat control diet (LF) or a high-fat, high-cholesterol diet (HF). Rabbits received a test meal containing [3H]cholesterol and [14C]triolein on days 0 and 63 for the LF group and days 14, 28, 42, 63 and 84 for the HF group. Blood was collected 24 h post-absorptively and 10, 24, 34 and 48 h after test-meal intake. Post-absorptive as well as postprandial lipoproteins and lipaemia were not modified in the LF rabbits, who did not show any atheroma deposition on day 119. In HF rabbits, postprandial plasma triacylglycerols peaked 24-34 h after meal intake. The 0-48 h areas under the curves of triacylglycerol and triacylglycerol-rich lipoproteins (TRL) steadily increased with time of chronic lipid feeding with values significantly higher than those in the LF rabbits. The postprandial plasma and TRL concentrations of dietary radiolabelled lipids were significantly higher in HF than LF rabbits. Post-heparin lipoprotein lipase (EC 3.1.1.34) and hepatic lipase (EC 3.1.1.3) activities were twofold higher in HF rabbits than in LF rabbits at day 105. In HF rabbits, a marked atheroma plaque deposition in the aorta was observed (30.9 (SE 3.9) % of total surface). The extent of atheroma deposition was positively correlated to the postprandial responses of plasma total triacylglycerols and dietary-derived lipids as well as total cholesterol and dietary-derived cholesterol in HF rabbits. In conclusion, chronic ingestion of a HF diet led to marked increases in postprandial lipaemia and TRL particles, and atheroma deposition.

Postprandial lipemia in relation to sterol and fat excretion in ileostomy subjects given oat-bran and wheat test meals

To investigate the mechanisms behind the serum cholesterol-lowering effect of oat fiber, we simultaneously measured postprandial lipid responses, serum lathosterol concentrations, and small bowel excretion of fat and sterols in ileostomy subjects given test meals high or low in oat fiber. Six ileostomy subjects (three women and three men) were served an oat-bran test meal (OB; 16.3 g fiber) and a wheat test meal (6.3 g fiber) in random order. After the postprandial 7-h period, a controlled, low-fat, cholesterol-free diet was served and ileostomy effluent was sampled throughout the 24-h period. Bile acid and fat excretion (24 h) increased by 93% and 146%, respectively (P < 0.05), and total and endogenous cholesterol excretion decreased by 14% and 19%, respectively (P < 0.05), after the OB test meal. The change in hepatic cholesterol synthesis was strongly related to the change in bile acid excretion (Spearman r = 0.89, P < 0.02). The postprandial chylomicron lipid concentration tended to be lower after the OB test meal (-43% for cholesterol, P = 0.07) whereas there was no difference in cholesterol absorption measured by isotope in five subjects. The main effect of the viscous oat beta-glucan seems to be related to increased bile acid excretion and subsequent changes in synthesis and endogenous excretion of cholesterol. An additional effect may have been a delay in the micellar lipid solubilization process and a consequent reduction in the secretion of chylomicrons into the circulation.