Porcine Skin Gelatin Hydrolysate Promotes Longitudinal Bone Growth in Adolescent Rats

Advances in the authentication of collagen products based on DNA technology

Collagenous products are making their way into consumer markets such as foods, nutraceuticals, cosmetics and pharmaceuticals increasingly. Collagen in a large family of proteins is ubiquitous in metazoan. The most effective way to identify biological samples including collagen is DNA technology indisputably. However, the DNA content of collagen mostly derived from connective tissue is relatively less, and commercial collagen products are usually subjected to some harsh treatments in the production process, which makes DNA damage more serious, thus tracing their origin becomes a huge challenge. At present, DNA enrichment mainly relies on silica based centrifugal columns after extraction by classical phenol chloroform method. For improving the amplification of DNA fragments, small amplicons are designed based on more stable mitochondrial genes, such as cytochrome b gene (cytb). In addition to conventional PCR for DNA amplification, some new PCR techniques have also been developed, such as DNA barcoding techniques, PCR-Southern hybridization and fluorescent PCR. These PCR techniques have their pros and cons, and are mainly used in the identification of gelatin at present. The development of a complete set of DNA authentication is of great significance for the control of collagen products quality and will contribute to sustainable development of collagen industry.

Hydrolyzed Collagen Tripeptide Promotes Longitudinal Bone Growth in Childhood Rats via Increases in Insulin-Like Growth Factor-1 and Bone Morphogenetic Proteins

Previous studies have reported that collagen tripeptide (CTP) derived from collagen hydrolysate has various beneficial effects on health by protecting against skin aging and improving bone formation and cartilage regeneration. Collagen-Tripep20TM (CTP20), which is a low-molecular-weight CTP derived from fish skin, contains a bioactive CTP, Gly-Pro-Hyp >3.2% with a tripeptide content >20%. Herein, we investigated the osteogenic effects and mechanisms of CTP20 (<500 Da) on MG-63 osteoblast-like cells and SW1353 chondrocytes. And we measured promoting ratio of the longitudinal bone growth in childhood rats. First, CTP20 at 100 μg/mL elevated the proliferation (15.0% and 28.2%), alkaline phosphatase activity (29.3% and 32.0%), collagen synthesis (1.25- and 1.14-fold), and calcium deposition (1.18- and 1.15-fold) in MG-63 cells and SW1353, respectively. In addition, we found that CTP20 could promote the longitudinal growth and height of the growth plate of the tibia in childhood rats. CTP20 enhanced the protein expression of insulin-like growth factor-1 (IGF-1) in MG-63 and SW1353 cells, and in the growth plate of childhood rats, along with Janus Kinase 2, and signal transducer and activator of transcription 5 activation in MG-63 and SW1353 cells. CTP20 also elevated the expression levels of bone morphogenetic proteins (BMPs) in MG-63 and SW1353 cells and in the growth plates of childhood rats. These results indicate that CTP20 may promote the endochondral ossification and longitudinal bone growth, through enhancing of IGF-1 and BMPs. (Clinical Trial Registration number: smecae 19-09-01).

Metabolomics strategy reveals the osteogenic mechanism of yak (Bos grunniens) bone collagen peptides on ovariectomy-induced osteoporosis in rats

Our previous work demonstrated that yak bone collagen peptides (YBP) possessed excellent osteogenic activity in vitro. However, associations between YBP and osteoporosis were less established, and the positive effect and underlying mechanism of YBP in the treatment of osteoporotic rats in vivo remained unclear. Herein, ovariectomized rats were intragastrically administered with YBP or 17β-estradiol for 12 weeks. Bone turnover markers, bone biomechanical parameters and bone microarchitecture were investigated to identify the specific changes of potential antagonistic effects of YBP on ovariectomized rats. Then, serum samples were analyzed by UPLC/Q-TOF-MS to identify metabolites. The results showed that YBP treatment remarkably altered the content of serum bone turnover markers and prevented the ovariectomy-induced deterioration of bone mechanical and microarchitecture characteristics. A total of forty-one biomarkers for which levels changed markedly upon treatment have been identified based on non-targeted metabolomics. Among them, twenty-one metabolites displayed a downward expression level, while twenty metabolites showed an upward expression level in the YBP group and finally were selected as potential biomarkers. The levels of these biomarkers displayed significant alterations and a tendency to be restored to normal values in YBP treated osteoporotic rats. A systematic network analysis of their corresponding pathways delineated that the protective or recovery effect of YBP on osteoporosis occurred primarily by regulating the amino acid metabolism and lipid metabolism (especially unsaturated fatty acid). Collectively, these findings highlight that such peptides hold promise in further advancement as a natural alternative for functional and health-promoting foods, which could be potentially used in mediated treatment of osteoporosis.

Pig Skin Gelatin Hydrolysates Attenuate Acetylcholine Esterase Activity and Scopolamine-induced Impairment of Memory and Learning Ability of Mice

The protective effect of pig skin gelatin water extracts (PSW) and the low molecular weight hydrolysates of PSW generated via enzymatic hydrolysis with Flavourzyme® 1000L (LPSW) against scopolamine-induced impairment of cognitive function in mice was determined. Seventy male ICR mice weighing 20–25 g were randomly assigned to seven groups: Control (CON); scopolamine (SCO, 1 mg/kg B.W., intraperitoneally (i.p.); tetrahydroaminoacridine 10 [THA 10, tacrine; 10 mg/kg B.W. per oral (p.o.) with SCO (i.p.)]; PSW 10 (10 mg/kg B.W. (p.o.) with SCO (i.p.); PSW 40 (40 mg/kg B.W. (p.o.) with SCO (i.p.); LPSW 100 (100 mg/kg B.W. (p.o.) with SCO (i.p.); LPSW 400 (400 mg/kg B.W. (p.o.) with SCO (i.p.). All treatment groups, except CON, received scopolamine on the day of the experiment. The oxygen radical absorbance capacity of LPSW 400 at 1 mg/mL was 154.14 μM Trolox equivalent. Administration of PSW and LPSW for 15 weeks did not significantly affect on physical performance of mice. LPSW 400 significantly increased spontaneous alternation, reaching the level observed for THA and CON. The latency time of animals receiving LPSW 400 was higher than that of mice treated with SCO alone in the passive avoidance test, whereas it was shorter in the water maze test. LPSW 400 increased acetylcholine (ACh) content and decreased ACh esterase activity (p<0.05). LPSW 100 and LPSW 400 reduced monoamine oxidase-B activity. These results indicated that LPSW at 400 mg/kg B.W. is a potentially strong antioxidant and contains novel components for the functional food industry.

Hydrolysis Process Optimization and Functional Characterization of Yak Skin Gelatin Hydrolysates

Yak (Bos grunniens) is an animal mainly living on the Tibetan Plateau. Yak skin is a valuable resource that is wasted in the meat production process. This study aimed to prepare yak skin gelatin hydrolysates (YSGH) from yak skin through enzymatic hydrolysis and investigate functional characterization of YSGH. We showed that trypsin was more effective than neutrase, papain, and pepsin in increasing the degree of hydrolysis (DH) of YSGH. The conditions of enzymatic hydrolysis were optimized using central composite design (CCD) and response surface method (RSM), and the highest DH value of 31.96% was obtained. We then analyzed the amino acid compositions and molecular weight distribution of peptides in YSGH. The obtained YSGH exhibited certain antioxidant activity and excellent ACE-inhibitory activity (IC50 = 0.991 mg/mL). In addition, the solubility (98.79%), emulsification, and foaming properties of YSGH developed here were also evaluated. With these physicochemical and biological functions, YSGH had potential applications in food, pharmaceuticals, and cosmetics as an ingredient.

Human Enriched Serum Following Hydrolysed Collagen Absorption Modulates Bone Cell Activity: from Bedside to Bench and Vice Versa

Collagen proteins are crucial components of the bone matrix. Since collagen-derived products are widely used in the food and supplement industry, one may raise the question whether collagen-enriched diets can provide benefits for the skeleton. In this study, we designed an innovative approach to investigate this question taking into account the metabolites that are formed by the digestive tract and appear in the circulation after ingestion of hydrolysed collagen. Blood samples collected in clinical and pre-clinical trials following ingestion and absorption of hydrolysed collagen were processed and applied on bone-related primary cell cultures. This original ex vivo methodology revealed that hydrolysed collagen-enriched serum had a direct impact on the behaviour of cells from both human and mouse origin that was not observed with controls (bovine serum albumin or hydrolysed casein-enriched serum). These ex vivo findings were fully in line with in vivo results obtained from a mouse model of post-menopausal osteoporosis. A significant reduction of bone loss was observed in mice supplemented with hydrolysed collagen compared to a control protein. Both the modulation of osteoblast and osteoclast activity observed upon incubation with human or mouse serum ex vivo and the attenuation of bone loss in vivo, clearly indicates that the benefits of hydrolysed collagen for osteoporosis prevention go beyond the effect of a simple protein supplementation.

Effects of collagen peptides intake on skin ageing and platelet release in chronologically aged mice revealed by cytokine array analysis

Action mechanisms underlying various biological activities of collagen peptides (CPs) remained to be elucidated. Cytokines may play an important role in mediating these health benefits of CPs. This study aimed to systemically examine the cytokines in skin and blood regulated by CPs intake. Thirteen‐month‐old female Kunming mice were administered with CPs for 2 months (0 or 400 mg/kg bodyweight/day). The cytokines in skin and plasma were analysed using a 53‐cytokine array and corresponding ELISA kits. In skin, CPs intake significantly down‐regulated placenta growth factor (PIGF‐2), insulin‐like growth factor (IGF)‐binding protein (IGFBP) ‐2 and IGFBP‐3, and up‐regulated platelet factor 4 (PF4), serpin E1 and transforming growth factor (TGF)‐β₁. CPs treatment also increased the type I collagen mRNA and protein levels and improved the aged skin collagen fibres. In plasma, nine cytokines were significantly down‐regulated by CPs intake compared to the model group: fibroblast growth factor (FGF)‐2, heparin‐binding (HB) epidermal growth factor (EGF)‐like growth factor (HB‐EGF), hepatocyte growth factor (HGF), platelet‐derived growth factor (PDGF)‐AB/BB, vascular endothelial growth factor (VEGF), chemokine (C‐X‐C motif) ligand 1 (KC), matrix metalloproteinase (MMP)‐9, interleukin (IL)‐1α and IL‐10; 2 cytokines were significantly up‐regulated, including TGF‐β₁ and serpin F1. Furthermore, CPs intake significantly decreased the level of platelet release indicators in the plasma and washed platelets, including PF4, granule membrane protein (GMP)‐140, β‐thromboglobulin and serotonin. These results provide a mechanism underlying anti‐skin ageing by CPs intake and highlight potential application of CPs as a healthcare supplement to combat cancer and cardiovascular disease by inhibiting platelet release.

Biological effect of hydrolyzed collagen on bone metabolism

Osteoporosis is a chronic and asymptomatic disease characterized by low bone mass and skeletal microarchitectural deterioration, increased risk of fracture, and associated comorbidities most prevalent in the elderly. Due to an increasingly aging population, osteoporosis has become a major health issue requiring innovative disease management. Proteins are important for bone by providing building blocks and by exerting specific regulatory function. This is why adequate protein intake plays a considerable role in both bone development and bone maintenance. More specifically, since an increase in the overall metabolism of collagen can lead to severe dysfunctions and a more fragile bone matrix and because orally administered collagen can be digested in the gut, cross the intestinal barrier, enter the circulation, and become available for metabolic processes in the target tissues, one may speculate that a collagen-enriched diet provides benefits for the skeleton. Collagen-derived products such as gelatin or hydrolyzed collagen (HC) are well acknowledged for their safety from a nutritional point of view; however, what is their impact on bone biology? In this manuscript, we critically review the evidence from literature for an effect of HC on bone tissues in order to determine whether HC may represent a relevant alternative in the design of future nutritional approaches to manage osteoporosis prevention.

Collagen hydrolysates increased osteogenic gene expressions via a MAPK signaling pathway in MG-63 human osteoblasts

The present study investigated the effects of CHs on osteogenic activities and MAPK-regulation on bone matrix gene expressions. The effects of CHs on cell proliferation, alkaline phosphatase (ALP) activity, collagen synthesis, and mineralization were measured in human osteoblastic MG-63 cells. Activation of MAPKs and downstream transcription factors such as extracellular-signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal kinase 1/2 (JNK1/2), p38, ELK1, and cJUN was examined using Western blot analysis. The expressions of osteogenic genes were measured by quantitative real-time PCR. CHs dose-dependently increased MG-63 cell proliferation, ALP activity, collagen synthesis, and calcium deposition. CHs activated ERK1/2, JNK1/2, p38, and ELK1 phosphorylation except cJUN. The COL1A1 (collagen, type I, alpha 1), ALPL (alkaline phosphatase), BGLAP (osteocalcin), and SPP1 (secreted phosphoprotein 1, osteopontin) gene expressions were increased by CH treatment. The ERK1/2 inhibitor (PD98509) blocked the CH-induced COL1A1 and ALPL gene expression, as well as ELK1 phosphorylation. The JNK1/2 inhibitor (SP600125) abolished CH-induced COL1A1 expression. The p38 inhibitor (SB203580) blocked CH-induced COL1A1 and SPP1 gene expression. In conclusion, CH treatment stimulates the osteogenic activities and increases bone matrix gene expressions via the MAPK/ELK1 signaling pathway. These results could provide a mechanistic explanation for the bone-strengthening effects of CHs.

Potential application of hydrolyzed fish collagen for inducing the multidirectional differentiation of rat bone marrow mesenchymal stem cells

Hydrolyzed fish collagen (HFC) has recently attracted considerable attention because of its outstanding bioactivity. However, few studies have been performed to determine the biological effects of HFC on bone marrow mesenchymal stem cells (BMSCs), which are often used in regenerative medicine. In this study, the molecular weight, amino acid composition, and contact angle of HFC were measured. The influence of HFC on cell viability and the multidirectional differentiation of BMSCs into osteogenic, endothelial, adipogenic, chondrogenic, and neural lineages were also assessed. Furthermore, the mechanism by which HFC promotes osteogenesis was investigated at the protein level. The molecular weight of HFC ranged from 700 to 1300 Da, the contact angle of HFC was approximately 26°, and HFC was found to be composed of various amino acids, including glycine, proline, and hydroxyproline. At a concentration of 0.2 mg/mL, HFC promoted cell viability, and significantly up-regulated the expression of osteogenic markers (RUNX2, ALP, OPN, and OCN), as well as endothelial markers (CD31, VE-cadherin, and VEGFR2). Western blot results indicated that treatment of BMSCs with 0.2 mg/mL HFC could activate the MAPK/ERK signaling pathway and then increase the protein level of RUNX2, while treatment with PD98059, a specific inhibitor of ERK1/2, could significantly inhibit the expression of P-ERK and RUNX2. Interestingly, real-time PCR demonstrated that HFC inhibited the expression of adipogenic markers (LPL and ADFP) and chondrogenic markers (aggrecan and COLII), whereas it had no effect on neural differentiation markers (MAP2 and β3-tubulin). In summary, this study suggests that without the use of any additional inducing reagent, HFC has the potential to actively promote osteogenic and endothelial differentiation because of its high hydrophilicity and the optimal extracellular microenvironment supplied by its amino acids. This research also revealed that HFC inhibited adipogenic and chondrogenic differentiation, but it had no influence on the neural differentiation of rat bone marrow mesenchymal stem cells (rBMSCs).