Effects of highly purified sardine proteins on lipid peroxidation and reverse cholesterol transport in rats fed a cholesterol-rich diet

Effects of diets containing proteins from fish muscles or fish by-products on the circulating cholesterol concentration in rodents: a systematic review and meta-analysis

A high circulating cholesterol concentration is considered an important risk factor for the development of CVD. Since lean fish intake and fish protein supplementation have been associated with lower cholesterol concentration in some but not all clinical studies, the main aim of this study was to investigate the effect of diets containing proteins from fish muscles and fish by-products on the serum/plasma total cholesterol (TC) concentration in rodents. A systematic literature search was performed using the databases PubMed, Web of Science and Embase, structured around the population (rodents), intervention (type of fish and fraction, protein dose and duration), comparator (casein) and the primary outcome (circulating TC). Articles were assessed for risk of bias using the SYRCLE's tool. A meta-analysis was conducted in Review Manager v. 5·4·1 (the Cochrane Collaboration) to determine the effectiveness of proteins from fish on the circulating TC concentration. Thirty-nine articles were included in the systematic review and meta-analysis, with data from 935 rodents. The risk of bias is unclear since few of the entries in the SYRCLE's tool were addressed. Consumption of proteins from fish resulted in a significantly lower circulating TC concentration when compared with control groups (mean difference -0·24 mmol/l, 95 % CI - 0·34, -0·15, P < 0·00001), with high statistical heterogeneity (I² = 71 %). To conclude, proteins from fish muscles and by-products show promise as a functional dietary ingredient or supplement by preventing high cholesterol concentration in rodents, thus reducing one of the most important risk factors for developing CVD.

Alterations of HDL's to piHDL's Proteome in Patients with Chronic Inflammatory Diseases, and HDL-Targeted Therapies

Chronic inflammatory diseases, such as rheumatoid arthritis, steatohepatitis, periodontitis, chronic kidney disease, and others are associated with an increased risk of atherosclerotic cardiovascular disease, which persists even after accounting for traditional cardiac risk factors. The common factor linking these diseases to accelerated atherosclerosis is chronic systemic low-grade inflammation triggering changes in lipoprotein structure and metabolism. HDL, an independent marker of cardiovascular risk, is a lipoprotein particle with numerous important anti-atherogenic properties. Besides the essential role in reverse cholesterol transport, HDL possesses antioxidative, anti-inflammatory, antiapoptotic, and antithrombotic properties. Inflammation and inflammation-associated pathologies can cause modifications in HDL's proteome and lipidome, transforming HDL from atheroprotective into a pro-atherosclerotic lipoprotein. Therefore, a simple increase in HDL concentration in patients with inflammatory diseases has not led to the desired anti-atherogenic outcome. In this review, the functions of individual protein components of HDL, rendering them either anti-inflammatory or pro-inflammatory are described in detail. Alterations of HDL proteome (such as replacing atheroprotective proteins by pro-inflammatory proteins, or posttranslational modifications) in patients with chronic inflammatory diseases and their impact on cardiovascular health are discussed. Finally, molecular, and clinical aspects of HDL-targeted therapies, including those used in therapeutical practice, drugs in clinical trials, and experimental drugs are comprehensively summarised.

Hypolipidemic effects of protein hydrolysates from Trachinotus ovatus and identification of peptides implied in bile acid-binding activity using LC-ESI-Q-TOF-MS/MS

In the present work, analysis of the hypolipidemic properties of Trachinotus ovatus protein hydrolysates (TOPHs) and identification of peptides with bile acid-binding activity were performed. Hydrolysates prepared by trypsin digestion exhibited the highest in vitro bile acid-binding capacities compared with hydrolysates prepared with the other four proteases and were mainly composed of small peptides and amino acids with molecular weights <3 kDa, accounting for 77.30%. Among the five ultra-filtration fractions of TOPHs, TOPHs-5 (<3 kDa) exhibited the highest in vitro bile acid-binding capacity, which was equivalent to 77.97% of cholestyramine at the same concentration. A total of 68 peptides were identified from TOPHs-5 by LC-ESI-Q-TOF-MS/MS and 9 of them had hydrophobicity of more than 60%. These highly hydrophobic peptides might be associated with the bile acid-binding activity of TOPHs-5. In vivo experiments indicated that the TOPHs could effectively reduce total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and the atherogenic index (AI), while they could evidently increase the high-density lipoprotein cholesterol (HDL-C) content. Furthermore, TOPHs exerted a marked protective effect on hepatorenal function, as evidenced by decreased levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and creatinine (CREA). Histopathological studies confirmed that TOPHs evidently protected the liver from histological alterations. In summary, for the first time, hypolipidemic effects and subsequential identification were obtained from TOPHs, which are promising natural ingredients that could potentially be employed in the management of hyperlipidemia.

For the first time, the hypolipidemic effect of Trachinotus ovatus protein hydrolysates was obtained and its active peptides were identified.

[Sardine purified proteins improve blood pressure, glycemic control, anti-atherogenic metabolic pathways and antioxidant capacity in obese rats]

AIM OF THE STUDY

The effects of sardine by-products (SBy-P) and fillet proteins (SF-P) were compared to casein (Cas) ; these effects were assessed on blood pressure, glycemic control, reverse cholesterol transport, lipid peroxidation and total antioxidant capacity in obese rats.

MATERIALS AND METHODS

Eighteen male Wistar rats were subjected for three months, to a high-fat diet. The obese rats were divided into three groups and consumed the same high-fat diet for 28 days after addition of either, 20% SBy-P, SF-P or Cas.

RESULTS

The sardine proteins (SBy-P and SF-P) compared respectively to Cas, reduced diastolic (-14%, -11% P<0.05) and systolic pressures (-12%, -8% P<0.05), blood glucose (-24%, -21% P<0.05), glycated hemoglobin (-28%, -21% P<0.05), insulinemia (-29%, -18% P<0.05) and HOMA-IR index (-29%, -18% P<0.05). They improve the reverse cholesterol transport by increasing the lecithin: cholesterol acyltransferase (LCAT) activity (+43%, +30% P<0.05) and high-density lipoproteins in cholesterol esters (+108%, +88% P<0.05), and decreasing the atherogenicity ratios and membrane fluidity (P<0.05). Furthermore, SBy-P and SF-P induced a reduction of reactive thiobarbituric acid substances concentrations in heart (-45%, -25% P<0.05), aorta (-62%, -41% P<0.05), liver (-40%, -21% P<0.05) and adipose tissue (-50%, -37% P<0.05) with an improvement in antioxidant capacity.

CONCLUSION

Sardine proteins, in particular those extracted from by-products, because of their hypotensive, hypoglycemic, anti-atherogenic and antioxidant properties, may have protective effects against the cardiovascular risk associated with obesity.

Evaluation of hypocholesterolemic effect and antioxidant activity of Boops boops proteins in cholesterol-fed rats

Dietary proteins affect blood cholesterol concentrations and antioxidant status, which are related to several diseases, including cardiovascular disease. The present study attempts to investigate the potential of Boops boops proteins (Bb-NHP) and its hydrolysate (Bb-HP) in the prevention of hypercholesterolemia and oxidative stress in rats fed a high cholesterol diet (HCD). After four weeks' treatment, serum lipid profiles (total cholesterol, triglycerides, HDL-cholesterol and LDL-cholesterol), the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), the level of malonaldehyde (MDA) and the activities of antioxidant enzymes [catalase (CAT) and glutathione peroxidase (GPx)] in liver were determined. Compared with those fed a standard diet, high cholesterol diet induced dyslipidemia, oxidative stress, and aortic structure alterations. Interestingly, supplementing the HCD with Boops boops proteins attenuated these anomalies in a dose-dependent manner. These observations suggested that B. boops proteins might provide health benefits by helping to reduce the deleterious effects of increased intake of cholesterol that characterize modern diets.