Effects of Chronic Whey Protein Supplementation on Atherosclerosis in ApoE-/- Mice

Liver triacylglycerol accumulation but not postprandial lipemia is reduced by a skim milk powder diet in male rats

Increases in postprandial lipids are linked to the development of cardiometabolic and fatty liver disease. Prior work has suggested that dairy possesses beneficial cardiometabolic effects and thus the aim of the current investigation was to test the hypotheses that the habitual consumption of dairy, in the form of skim milk powder (SMP), would protect against increases in circulating lipids and liver lipid accumulation following an oral fat challenge in rats. Male rats were fed either a semipurified low-fat control diet with casein or a diet with an equivalent amount of protein (∼13% kcal) provided through skim milk powder (SMP) for 6 weeks (n = 40/group). Rats were then given an oral gavage of palm oil (5 mL/kg body weight) or an equivalent volume of water, and serum and liver were harvested 90 minutes or 4 hours after. Rats fed the SMP diet gained less weight than controls but there were no differences in glucose tolerance between groups. The fat gavage increased serum lipids in both diet groups, whereas there was a main effect of the fat challenge to increase, and the SMP diet, to decrease liver triacylglycerol accumulation. The percentage of saturated and monounsaturated fatty acids and the protein content/activity of lipogenic enzymes were reduced in livers from SMP-fed rats, whereas the percentage of polyunsaturated fatty acids was increased. In summary, we provide evidence that SMP consumption, although not protecting against postprandial lipemia, markedly attenuates triacylglycerol accumulation and the relative amount of saturated and monounsaturated fatty acids in the liver.

Whey protein hydrolysate alleviated atherosclerosis and hepatic steatosis by regulating lipid metabolism in apoE-/- mice fed a Western diet

Whey protein hydrolysate (WPH) has been proved to possess various biological activities associated with the amelioration of cardiovascular disease (CVD). The objective of this study was to investigate the anti-atherosclerotic and hepatoprotective effects of WPH on apolipoprotein E knockout (apoE^-/-) mice fed with a Western diet for 15 weeks. Results revealed that WPH markedly inhibited the development of atherosclerotic lesions in the aorta and steatosis injury in the liver. The serum lipid and inflammation levels were both reduced after WPH supplemented in apoE^-/- mice. In addition, WPH inhibited the lipid accumulation in the liver, thereby decreasing the hepatic inflammation level and oxidative stress injury. Mechanism investigation revealed that WPH down-regulated the expression of cholesterol biosynthesis genes while up-regulated the expression of cholesterol uptake and excretion genes in the liver. Meanwhile, the de novo lipogenesis was inhibited while the fatty acids β-oxidation was activated in the liver by WPH supplementation. Notably, the n-3 polyunsaturated fatty acid (PUFA)/n-6 PUFA ratio in serum and liver of the WPH-H group were 2.69-fold (p < 0.01) and 3.64-fold (p < 0.01) higher than that of the Model group. Collectively, our results proved WPH possesses potent anti-atherosclerotic and hepatoprotective activities and has the potential to be used as a novel functional ingredient for the management of CVD.

Dosage of Dual-Protein Nutrition Differentially Impacts the Formation of Atherosclerosis in ApoE-/- Mice

Atherosclerosis (AS) is recognized as the original cause of most cardiovascular and cerebrovascular diseases. The dual-protein (DP) nutrition that consists of soy protein and whey protein is reported to be associated with a reduction in AS; however, the relationship between DP and AS remains ambiguous. Therefore, this study aimed to verify the effect of DP on AS and explore the optimal DP intake to improve AS. ApoE^−/− mice were administrated with low- (LDP), middle- (MDP), and high-dose (HDP) DP. The MDP group exhibited significant improvements in AS. In terms of lipid metabolism, the levels of plasma total triglyceride and LDL-C and the mRNA expression levels of Cyp7a1 and PCSK9 were markedly tuned in the MDP group. In addition, the MDP treatment group had a substantially lower inflammatory response and better intestinal barrier function than LDP and HDP groups. The species richness demonstrated by the Chao1 index was distinctly increased in the MDP group, and the relative abundance of intestinal-permeability-protective microbes Blautia and Akkermansia was significantly elevated. In summary, an adequate intake of DP was able to counteract atherosclerosis development in ApoE^−/− mice, and this study provides a scientific theoretical basis for the application of DP in the food and pharmaceutical fields.

Changes in histological structure and nitric oxide synthase expression in aorta of rats supplemented with bee pollen or whey protein

Various protein-based supplements are at least periodically consumed by 30%-40% of sportspeople. The current study compares cardiovascular effects of diet supplementation with 2 different protein-rich products: bee pollen and whey protein. Thirty Wistar rats were divided into 2 groups, one subjected to daily moderate physical activity and one not. Each group consisted of 3 subgroups: control, whey-protein-supplemented, and bee-pollen-supplemented. After 8 weeks, rats were decapitated, and proximal parts of thoracic aortas were collected and embedded in paraffin blocks. Histological slides were stained according to standard hematoxylin and eosin, Masson's trichrome, and Verhoeff - Van Gieson staining. Special immunohistochemical stains against neuronal nitric oxide synthase (nNOS), endothelial nitric oxide synthase (eNOS), and alpha smooth muscle actin were also prepared. Histological evaluation revealed noticeable changes in all supplemented groups: disturbances in elastic laminae, slight increase in collagen deposition, and significantly lowered nNOS and eNOS expression. The prevalence of small atherosclerotic plaques was the highest in non-running supplemented groups, while in running supplemented groups it resembled the prevalence in control groups. Both running groups had thinner tunica media than control. Both supplements exert visible effects on aortic structure, but the difference between them is far less evident. In some aspects, however, the bee pollen seems to be even slightly more harmful, which may be related to various possible contaminants like mycotoxins or pesticides.

Effect of whey protein on blood pressure in pre- and mildly hypertensive adults: A randomized controlled study

In China, the frequency of mild hypertension cases remains prevalently high. Meanwhile, diets containing functional ingredients that control blood pressure have received considerable attention. In this randomized, controlled intervention study, 65 participants were randomly assigned to consume 30 g of whey protein or maltodextrin daily for 12 weeks. Blood pressure, body composition, biochemical analysis in plasma, and flow-mediated dilation (FMD), an index for evaluating endothelial function, were measured. Finally, 54 participants (27 participants in each group) completed the study. At the end of the intervention, the average systolic blood pressure (SBP) was 129.5 ± 7.7 mmHg in the control group and 128.2 ± 6.9 mmHg in the whey protein group (p = 0.052). In the overweight and obese participants, the SBP was significantly lower in the whey protein group than in the control group (126.5 ± 6.9 mmHg vs. 128.8 ± 7.4 mmHg, p = 0.033), and body fat, fat percentage, and waist circumference significantly decreased in the whey protein group (p = 0.010, 0.016, 0.019, respectively). No difference was observed between the control and whey protein groups with regard to the changes in plasma lipids, inflammatory cytokines, antioxidative indexes, endothelium-1, nitric oxide, angiotensin II, and angiotensin-converting enzyme. The increase in FMD was significantly higher in the whey protein group than in the control group (5.2% vs. 0.3%, p = 0.040). In conclusion, whey protein significantly decreased SBP in pre- and mildly hypertensive adults, who are also overweight and obese. Whey protein also improved endothelial function. The lowering effect of blood pressure was probably related to body fat loss in these participants.

Effects of Metformin Combined with Lactoferrin on Lipid Accumulation and Metabolism in Mice Fed with High-Fat Diet

Metformin (Met) and lactoferrin (Lf) both exhibit beneficial effects on body weight management and lipid accumulation. However, the synergistical action of Met and Lf remains unclear. In this study, 64 mice were divided into five groups, namely, the control group, high-fat diet (HFD group), HFD with Met (Met group), Lf (Lf group), and a combination of Met and Lf (Met + Lf group). Met (200 mg/kg body weight) and Lf (2 g/100 mL) were administrated in drinking water. The experiment lasted for 12 weeks. Body weight, serum, and hepatic lipids were determined. Histology of the liver and perirenal fat was observed. Protein expression related to hepatic lipid metabolism was also measured. HFD significantly increased body weight, visceral fat weight, and lipid profiles, which lead to obesity and dyslipidemia in mice. Compared with the HFD group, the treatments significantly decreased body weight and Lee’s index (body mass index of mice) with the lowest values in the Met + Lf group. The treatments also decreased the weight of visceral fat, and improved circulating lipid profile and the ability for regulating glucose intake. The adipocyte size and serum TC level were significantly lower in the Met + Lf group as compared with those in the Met or Lf group. The treatments alleviated hepatic lipid accumulation, especially in the Met + Lf group. For protein expression, the p-AMPK/AMPK ratio, a key kinase-regulating cellular energy homeostasis, was significantly higher in the Met + Lf group than the ratio in the HFD group. Similarly, the treatments significantly downregulated the protein expression of lipogenic enzymes (FAS, ACC, and SREBP-1) and upregulated the protein expression of lipolytic enzyme (ATGL). The protein expression of HMGCoAR, which is an important rate limiting enzyme in cholesterol biosynthesis, was only significantly lower in the Met + Lf group than in the HFD group. In conclusion, Met and Lf, either alone or in combination, prevented HFD-induced obesity and improved lipid metabolism.