Lactopeptides and human blood pressure

Food protein-derived bioactive peptides for the management of nutrition related chronic diseases

Dietary intervention via modifications of dietary pattern or supplementations of naturally derived bioactive compounds has been considered as an efficient approach in management of nutrition related chronic diseases. Food protein-derived bioactive peptide is representative of natural compounds which show the potential to prevent or mitigate nutrition related chronic diseases. In the past decades, substantial research has been conducted concentrating on the characterization, bioavailability, and activity assessment of bioactive peptides. Although various activities of bioactive peptides have been reported, the activity testes of most peptides were only conducted in cells and animal models. Some clinical trials of bioactive peptides were also reported but only limited to antihypertensive peptides, antidiabetic peptides and peptides modulating blood lipid profile. Hereby, clinical evidence of bioactive peptides in management of nutrition-related chronic diseases is summarized in this chapter, which aims at providing implications for the clinical studies of bioactive peptides in the future.

In Silico identification of angiotensin-converting enzyme inhibitory peptides from MRJP1

Hypertension is considered as one of the most common diseases that affect human beings (both male and female) due to its high prevalence and also extending widely to both industrialize and developing countries. Angiotensin-converting enzyme (ACE) has a significant role in the regulation of blood pressure and ACE inhibition with inhibitory peptides is considered as a major target to prevent hypertension. In the current study, a blood pressure regulating honey protein (MRJP1) was examined to identify the ACE inhibitory peptides. The 3D structure of MRJP1 was predicted by utilizing the threading approach and further optimized by performing molecular dynamics simulation for 30 nanoseconds (ns) to improve the quality factor up to 92.43%. Root mean square deviation and root mean square fluctuations were calculated to evaluate the structural features and observed the fluctuations in the timescale of 30 ns. AHTpin server based on scoring vector machine of regression models, proteolysis and structural characterization approaches were implemented to identify the potential inhibitory peptides. The anti-hypertensive peptides were scrutinized based on the QSAR models of anti-hypertensive activity and the molecular docking analyses were performed to explore the binding affinities and potential interacting residues. The peptide "EALPHVPIFDR" showed the strong binding affinity and higher anti-hypertensive activity along with the global energy of -58.29 and docking score of 9590. The aromatic amino acids especially Tyr was observed as the key residue to design the dietary peptides and drugs like ACE inhibitors.

Whey-Derived Peptides Interactions with ACE by Molecular Docking as a Potential Predictive Tool of Natural ACE Inhibitors

Several milk/whey derived peptides possess high in vitro angiotensin I-converting enzyme (ACE) inhibitory activity. However, in some cases, poor correlation between the in vitro ACE inhibitory activity and the in vivo antihypertensive activity has been observed. The aim of this study is to gain insight into the structure-activity relationship of peptide sequences present in whey/milk protein hydrolysates with high ACE inhibitory activity, which could lead to a better understanding and prediction of their in vivo antihypertensive activity. The potential interactions between peptides produced from whey proteins, previously reported as high ACE inhibitors such as IPP, LIVTQ, IIAE, LVYPFP, and human ACE were assessed using a molecular docking approach. The results show that peptides IIAE, LIVTQ, and LVYPFP formed strong H bonds with the amino acids Gln 259, His 331, and Thr 358 in the active site of the human ACE. Interestingly, the same residues were found to form strong hydrogen bonds with the ACE inhibitory drug Sampatrilat. Furthermore, peptides IIAE and LVYPFP interacted with the amino acid residues Gln 259 and His 331, respectively, also in common with other ACE-inhibitory drugs such as Captopril, Lisinopril and Elanapril. Additionally, IIAE interacted with the amino acid residue Asp 140 in common with Lisinopril, and LIVTQ interacted with Ala 332 in common with both Lisinopril and Elanapril. The peptides produced naturally from whey by enzymatic hydrolysis interacted with residues of the human ACE in common with potent ACE-inhibitory drugs which suggests that these natural peptides may be potent ACE inhibitors.

Preparation, Bioavailability, and Mechanism of Emerging Activities of Ile-Pro-Pro and Val-Pro-Pro

Ile-Pro-Pro and Val-Pro-Pro are two most well-known food-derived bioactive peptides, initially identified as inhibitors of angiotensin I-converting enzyme (ACE) from a sample of sour milk. These two peptides were identified in fermented and enzymatic hydrolyzed cow and non-cow (that is, goat, sheep, buffalo, yak, camel, mare, and donkey) milk, as well as sourdough prepared from wheat, rye, and malt. Similar to other bioactive peptides, bioavailability of these peptides is low (about 0.1%), reaching picomolar concentration in human plasma; they showed blood pressure lowering activity in animals and in human, via improved endothelial function, activation of ACE2, and anti-inflammatory property. Emerging bioactivities of these two peptides toward against metabolic syndrome and bone-protection received limited attention, but may open up new applications of these peptides as functional food ingredients. Further studies are warranted to determine the best source as well as to identify novel enzymes (particularly from traditional fermented milk products) to improve the efficiency of production, to characterize possible peptide receptors using a combination of omics technology with molecular methods to understand if these two peptides act as signal-like molecules, to improve their bioavailability, and to explore new applications based on emerging bioactivities.

Egg ovotransferrin-derived ACE inhibitory peptide IRW increases ACE2 but decreases proinflammatory genes expression in mesenteric artery of spontaneously hypertensive rats

Scope

Egg ovotransferrin‐derived angiotensin converting enzyme (ACE) inhibitory peptide IRW was previously shown to reduce blood pressure in spontaneously hypertensive rats through reduced vascular inflammation and increased nitric oxide‐mediated vasorelaxation. The main objective of the present study was to investigate the molecular mechanism of this peptide through transcriptome analysis by RNAseq technique.

Methods and results

Total RNA was extracted from kidney and mesenteric arteries; the RNAseq libraries (from untreated and IRW‐treated groups) were constructed and subjected to sequence using HiSeq 2000 system (Illumina) system. A total of 12 764 and 13 352 genes were detected in kidney and mesenteric arteries, respectively. The differentially expressed (DE) genes between untreated and IRW‐treated groups were identified and the functional analysis through ingenuity pathway analysis revealed a greater role of DE genes identified from mesenteric arteries than that of kidney in modulating various cardiovascular functions. Subsequent qPCR analysis further confirmed that IRW significantly increased the expression of ACE‐2, ABCB‐1, IRF‐8, and CDH‐1 while significantly decreased the expression ICAM‐1 and VCAM‐1 in mesenteric arteries.

Conclusion

Our research showed for the first time that ACE inhibitory peptide IRW could contribute to its antihypertensive activity through increased ACE2 and decreased proinflammatory genes expression.

Molecular targets of antihypertensive peptides: understanding the mechanisms of action based on the pathophysiology of hypertension

There is growing interest in using functional foods or nutraceuticals for the prevention and treatment of hypertension or high blood pressure. Although numerous preventive and therapeutic pharmacological interventions are available on the market, unfortunately, many patients still suffer from poorly controlled hypertension. Furthermore, most pharmacological drugs, such as inhibitors of angiotensin-I converting enzyme (ACE), are often associated with significant adverse effects. Many bioactive food compounds have been characterized over the past decades that may contribute to the management of hypertension; for example, bioactive peptides derived from various food proteins with antihypertensive properties have gained a great deal of attention. Some of these peptides have exhibited potent in vivo antihypertensive activity in both animal models and human clinical trials. This review provides an overview about the complex pathophysiology of hypertension and demonstrates the potential roles of food derived bioactive peptides as viable interventions targeting specific pathways involved in this disease process. This review offers a comprehensive guide for understanding and utilizing the molecular mechanisms of antihypertensive actions of food protein derived peptides.

Milk, dairy products, and their functional effects in humans: a narrative review of recent evidence

Milk is a widely consumed beverage that is essential to the diet of several millions of people worldwide because it provides important macro- and micronutrients. Milk is recognized as being useful during childhood and adolescence because of its composition; however, its relatively high saturated fat proportion raises issues of potential detrimental effects, namely on the cardiovascular system. This review evaluates the most recent literature on dairy and human health, framed within epidemiologic, experimental, and biochemical evidence. As an example, the effects of milk (notably skimmed milk) on body weight appear to be well documented, and the conclusions of the vast majority of published studies indicate that dairy consumption does not increase cardiovascular risk or the incidence of some cancers. Even though the available evidence is not conclusive, some studies suggest that milk and its derivatives might actually be beneficial to some population segments. Although future studies will help elucidate the role of milk and dairy products in human health, their use within a balanced diet should be considered in the absence of clear contraindications.

The role of nutrition and nutraceutical supplements in the treatment of hypertension

Vascular biology, endothelial and vascular smooth muscle and cardiac dysfunction play a primary role in the initiation and perpetuation of hypertension, cardiovascular disease and target organ damage. Nutrient-gene interactions and epigenetics are predominant factors in promoting beneficial or detrimental effects in cardiovascular health and hypertension. Macronutrients and micronutrients can prevent, control and treat hypertension through numerous mechanisms related to vascular biology. Oxidative stress, inflammation and autoimmune dysfunction initiate and propagate hypertension and cardiovascular disease. There is a role for the selected use of single and component nutraceutical supplements, vitamins, antioxidants and minerals in the treatment of hypertension based on scientifically controlled studies which complement optimal nutrition, coupled with other lifestyle modifications.

The impact of milk proteins and peptides on blood pressure and vascular function: a review of evidence from human intervention studies

CVD are the leading cause of death worldwide. Hypertension, a major controllable risk factor of CVD, is intimately associated with vascular dysfunction, a defect which is also now recognised to be a major, modifiable risk factor for the development of CVD. The purpose of the present review was to critically evaluate the evidence for the effects of milk proteins and their associated peptides on blood pressure (BP) and vascular dysfunction. After a detailed literature search, the number of human trials evaluating the antihypertensive effects of casein-derived peptides (excluding isoleucine-proline-proline and valine-proline-proline) was found to be limited; the studies were preliminary with substantial methodological limitations. Likewise, the data from human trials that examined the effects of whey protein and peptides were also scarce and inconsistent. To date, only one study has conducted a comparative investigation on the relative effects of the two main intact milk proteins on BP and vascular function. While both milk proteins were shown to reduce BP, only whey protein improved measures of arterial stiffness. In contrast, a growing number of human trials have produced evidence to support beneficial effects of both milk proteins and peptides on vascular health. However, comparison of the relative outcomes from these trials is difficult owing to variation in the forms of assessment and measures of vascular function. In conclusion, there is an accumulating body of evidence to support positive effects of milk proteins in improving and/or maintaining cardiovascular health. However, the variable quality of the studies that produced this evidence, and the lack of robust, randomised controlled intervention trials, undermines the formulation of firm conclusions on the potential benefits of milk proteins and peptides on vascular health.

Fermented milk for hypertension

BACKGROUND

Fermented milk has been suggested to have a blood pressure lowering effect through increased content of proteins and peptides produced during the bacterial fermentation. Hypertension is one of the major risk factors for cardiovascular disease world wide and new blood pressure reducing lifestyle interventions, such as fermented milk, would be of great importance.

OBJECTIVES

To investigate whether fermented milk or similar products produced by lactobacilli fermentation of milk proteins has any blood pressure lowering effect in humans when compared to no treatment or placebo.

SEARCH METHODS

The Cochrane Central Register of Controlled Trials (CENTRAL), English language databases, including MEDLINE (1966-2011), EMBASE (1974-2011), Cochrane Complementary Medicine Trials Register, Allied and Complementary Medicine (AMED) (1985-2011), Food science and technology abstracts (1969-2011).

SELECTION CRITERIA

Randomised controlled trials; cross over and parallel studies evaluating the effect on blood pressure of fermented milk in humans with an intervention period of 4 weeks or longer.

DATA COLLECTION AND ANALYSIS

Data was extracted individually by two authors, afterwards agreement had to be obtained before imputation in the review.

MAIN RESULTS

A modest overall effect of fermented milk on SBP was found (MD -2.45; 95% CI -4.30 to -0.60), no effect was evident on DBP (MD -0.67; 95% CI -1.48, 0.14).

AUTHORS' CONCLUSIONS

The review does not support an effect of fermented milk on blood pressure. Despite the positive effect on SBP the authors conclude, for several reasons, that fermented milk has no effect on blood pressure. The effect found was very modest and only on SBP, the included studies were very heterogeneous and several with weak methodology. Finally, sensitivity and subgroup analyses could not reproduce the antihypertensive effect. The results do not give notion to the use of fermented milk as treatment for hypertension or as a lifestyle intervention for pre-hypertension nor would it influence population blood pressure.

Possible role of milk-derived bioactive peptides in the treatment and prevention of metabolic syndrome

The growing prevalence of metabolic syndrome as well as its impact on public health has garnered increased attention in recent years. As a result, metabolic syndrome is now considered one of the world's leading public health problems. Bioactive peptides deriving from milk proteins may play an important role in the prevention and treatment of metabolic syndrome and its complications via several mechanisms, such as the satiety response, the regulation of insulinemia levels and blood pressure, the uptake of free radicals, and alteration of the lipid profile. These peptides can be incorporated into functional foods or administered via nutraceuticals to decrease the risk of obesity, atherogenesis, arterial hypertension, and type 2 diabetes. Recent findings have generated considerable scientific and commercial interest in milk-derived bioactive peptides, leading to numerous publications on the effectiveness of these substances. This review summarizes the current knowledge on bioactive peptides derived from milk proteins and examines the potential value of these peptides in the treatment and prevention of metabolic syndrome and its complications.

The Extended Nutrigenomics - Understanding the Interplay between the Genomes of Food, Gut Microbes, and Human Host

Comprehensive investigation of nutritional health effects at the molecular level requires the understanding of the interplay between three genomes, the food, the gut microbial, and the human host genome. Food genomes are researched for discovery and exploitation of macro- and micronutrients as well as specific bioactives, with those genes coding for bioactive proteins and peptides being of central interest. The human gut microbiota encompasses a complex ecosystem in the intestine with profound impact on host metabolism. It is being studied at genomic and, more recently, also at proteomic and metabonomic level. Humans are being characterized at the level of genetic pre-disposition and inter-individual variability in terms of (i) response to nutritional interventions and direction of health trajectories; (ii) epigenetic, metabolic programming at certain life stages with health consequences later in life and even for subsequent generations; and (iii) acute genomic expression as a holistic response to diet, monitored at gene transcript, protein and metabolite level. Modern nutrition science explores health-related aspects of bioactive food components, thereby promoting health, preventing, or delaying the onset of disease, optimizing performance and assessing benefits and risks in individuals and subpopulations. Personalized nutrition means adapting food to individual needs, depending on the human host’s life stage, -style, and -situation. Traditionally, nutrigenomics and nutri(epi)genetics are seen as the key sciences to understand human variability in preferences and requirements for diet as well as responses to nutrition. This article puts the three nutrition and health-relevant genomes into perspective, namely the food, the gut microbial and the human host’s genome, and calls for an “extended nutrigenomics” approach in order to build the future tools for personalized nutrition, health maintenance, and disease prevention. We discuss examples of these genomes, proteomes, transcriptomes, and metabolomes under the definition of genomics as the overarching term covering essentially all Omics rather than the sole study of DNA and RNA.

Long-term intake of a milk casein hydrolysate attenuates the development of hypertension and involves cardiovascular benefits

Essential hypertension is considered a serious health problem and diet can play an important role in its prevention and treatment. The aim of this study was to evaluate the effect of the long-term intake of a product based on milk casein hydrolysate on the development of hypertension in spontaneously hypertensive rats (SHR). A daily dose of 800 mg/kg body weight of the casein hydrolysate product was administered dissolved in drinking water during 6 weeks. Systolic and diastolic blood pressures were measured weekly by the tail-cuff method. Endothelial function in aorta and mesenteric segments, left ventricular hypertrophy, endothelial nitric oxide synthase (eNOS) expression in aorta and plasmatic angiotensin conversion enzyme (ACE) activity were also evaluated at the end of treatment. The development of hypertension was attenuated in the group treated with the casein hydrolysate product; in this sense the systolic blood pressure increased 33±3 mmHg in control group and only 18±5 mmHg in the treated group during the experimental period. In addition, the treatment improved aorta and mesenteric acetylcholine relaxations and increased the eNOS expression in aorta. Left ventricular hypertrophy decreased in treated SHR accompanied by a significant decrease in interstitial fibrosis. These results warrant evaluation in humans to determine if the product based on a casein hydrolysate could be used as a functional food ingredient to prevent blood pressure increased with additional cardiovascular benefits.

Vascular effects of egg white-derived peptides in resistance arteries from rats. Structure-activity relationships

BACKGROUND

The vasodilator properties of several peptide sequences derived from egg white proteins were screened in mesenteric resistance arteries from Wistar-Kyoto rats. For this, third-order branches of the mesenteric arteries from 6-month-old male rats were used. The vasodilator responses, with or without endothelium, to several peptides (0.1 mmol L(-1)) were analysed in an isometric myograph. Moreover, the effect of nitric oxide (NO) synthase (L-NAME, 100 micromol L(-1)) and cyclooxygenase (indomethacin, 10 micromol L(-1)) inhibitors on the vasodilator response was tested.

RESULTS

The peptides Arg-Ala-Asp-His-Pro-Phe-Leu, Arg-Ala-Asp-His-Pro-Phe, Arg-Ala-Asp-His-Pro, Tyr-Arg-Gly-Gly-Leu-Glu-Pro-Ile-Asn-Phe, Arg-Asp-Ile-Leu-Asn-Gln and Val-Pro-Pro showed a high endothelium-dependent vasorelaxation, whereas Phe-Arg-Ala-Asp-His-Pro-Phe-Leu was only partially endothelium-dependent. The relaxation induced by Arg-Ala-Asp-His-Pro-Phe-Leu, Arg-Ala-Asp-His-Pro-Phe, Arg-Ala-Asp-His-Pro, Arg-Asp-Ile-Leu-Asn-Gln and Val-Pro-Pro was mainly mediated by NO, since the response was inhibited only by L-NAME, while both L-NAME and indomethacin inhibited the vasodilator response induced by Phe-Arg-Ala-Asp-His-Pro-Phe-Leu and Tyr-Arg-Gly-Gly-Leu-Glu-Pro-Ile-Asn-Phe. The presence of Arg or Tyr at the N-terminal position could be related to the vasodilator activity of these compounds in this vascular bed. The well-known angiotensin-converting enzyme inhibitor captopril showed only a slight vasodilator effect.

CONCLUSION

These peptides could reduce the vascular resistance and be used as functional ingredients in the prevention and/or treatment of hypertension and other associated disorders.