Skate Skin Research Articles

Genotoxicity evaluation of collagen peptide derived from skate (Raja kenojei) skin: In vitro and in vivo studies

Genotoxicity evaluation of collagen peptide derived from skate (Raja kenojei) skin: In vitro and in vivo studies

Identification of Novel Glycans in the Mucus Layer of Shark and Skate Skin.

The mucus layer covering the skin of fish has several roles, including protection against pathogens and mechanical damage. While the mucus layers of various bony fish species have been investigated, the composition and glycan profiles of shark skin mucus remain relatively unexplored. In this pilot study, we aimed to explore the structure and composition of shark skin mucus through histological analysis and glycan profiling. Histological examination of skin samples from Atlantic spiny dogfish (Squalus acanthias) sharks and chain catsharks (Scyliorhinus retifer) revealed distinct mucin-producing cells and a mucus layer, indicating the presence of a functional mucus layer similar to bony fish mucus albeit thinner. Glycan profiling using liquid chromatography-electrospray ionization tandem mass spectrometry unveiled a diverse repertoire of mostly O-glycans in the mucus of the two sharks as well as little skate (Leucoraja erinacea). Elasmobranch glycans differ significantly from bony fish, especially in being more sulfated, and some bear resemblance to human glycans, such as gastric mucin O-glycans and H blood group-type glycans. This study contributes to the concept of shark skin having unique properties and provides a foundation for further research into the functional roles and potential biomedical implications of shark skin mucus glycans.

Distribution, Typical Structure and Self-Assembly Properties of Collagen from Fish Skin and Bone.

The source and type of collagen are crucial to its application, and both play a decisive role. Collagen was prepared from both tilapia skin and bone and skate skin and cartilage, named as CI-TI-s, CI-TI-b, CI-SK-s, and CII-SK-c, respectively. Types, distributions, structures, and self-assembly of collagen were studied. It showed that yellow collagen fibers from skin arranged longitudinally, while collagen fibers from skate cartilages displayed varying colors. CI-TI-s, CI-TI-b, CI-SK-s, and CII-SK-c showed the typical amide A (3316-3336 cm-1) and amide B (2929-2948 cm-1) in FTIR spectra. CI-TI-b and CII-SK-c showed 218-229 nm of UV absorption, 11.56-12.20 Å of d values in XRD, and 0.12-0.14 of Rpn values in CD. The thermal denaturation temperatures of CI-TI-s and CI-SK-s were 30.7 and 20.6 °C, respectively. The self-assembly of CI-TI-s and CII-SK-c were maximum at pH 7.2 and 7.4-7.6, respectively. The unique collagen peptides of tilapia and skate were GPSGPQGAVGATGPK, PAMPVPGPMGPMGPR, SPAMPVPGPMGPMGPR, GESGPSGPAGPAGPAGVR, SSGPPVPGPIGPMGPR, GLTGPIGVPGPPGAQGEK, GLAGPQGPR, and GLSGDPGVQGIK, respectively. The unique peptides of type I and type II collagen were GPTGEIGATGLAGAR, GVLGLTGMR, LGLTGMR, GEPGAAGPAGPSGPMGPR, SSGPPVPGPIGPMGPR, and GLSGDPGVQGIK, respectively.

Toxicity of a 90-day repeated oral dose of a collagen peptide derived from skate (Raja kenojei) skin: a rat model study.

Collagen peptides are widely employed as therapeutic materials due to their numerous beneficial properties, including for the following uses: antiaging, antioxidant applications, antibacterial applications, wound healing, tissue engineering, medication delivery, and cosmetics. Although collagen peptides are useful in these applications, to our knowledge, few published studies have been undertaken on their repeated-dose toxicity. We evaluated the possible subchronic toxicity of a collagen peptide derived from skate (Raja kenojei) skin (CPSS) in Sprague-Dawley rats by administering repeated oral doses over 90 days. Rats of both sexes were assigned randomly to one of four experimental groups, respectively receiving 0, 500, 1000, or 2000mg/kg/day of CPSS. At all doses tested, repeated oral CPSS administration had no treatment-related adverse effects in terms of clinical signs, body weight, food consumption, detailed clinical observation, sensory reactivity, functional assessment, urinalysis, ophthalmic examination, gross pathology, hematology, serum biochemistry, hormone analysis, organ weight, and histopathology. Even though there were some alterations in hematologic parameters, serum biochemistry parameters, organ weight, and histopathological findings, these did not follow a dose-response pattern and were within historical limits for control rats. The oral no-observed-adverse-effect level (NOAEL) of the CPSS was 2000mg/kg/day for both male and female rats in the applied experimental circumstances, and no target organs were identified.

홍어 껍질 콜라겐 펩타이드의 지표성분 밸리데이션 및 생리활성

In this study, we developed and validated a high-performance liquid chromatography/photodiode array method for the quantification of glycine-proline-hydroxyproline (GPH) as a marker compound in skate skin collagen peptides (SCPs). The accurate molecular mass and amino acid sequence of this marker were determined using a QTOF mass spectrometer. Chromatographic separations were conducted using a 95:5 isocratic mobile phase of 0.1% trifluoroacetic acid (A) and acetonitrile/methanol (1:4 v/v, B) at a flow rate of 0.3 mL/min; the separated compounds were detected at 214 nm using a Jupiter® 4 μm Proteo 90Å column. The method was validated for specificity, linearity, limit of detection (LOD), limit of quantitation (LOQ), accuracy, and precision. It was found to be linear in the range of 1.0-50.0 μg/mL, with a good correlation coefficient (R2=0.9999) and excellent specificity. The LOD and LOQ were 0.07 and 0.22 μg/mL, respectively. A recovery study determined the accuracy of the method, with an average recovery of 103.76%, 100.35% and 103.97% of the marker at 10, 15 and 25 μg/mL, respectively, and a precision study showed a relative standard deviation of less than 2%. Additionally, the DPPH and ABTS radical scavenging activities of the SCPs increased in a concentration-dependent manner, and UV-protective effect was confirmed by human keratinocyte (HaCaT cell) viability. Our study thus provides the foundation for developing functional foods or cosmetics using SCPs.

Structure-function relationship of fermented skate skin gelatin-derived bioactive peptides: a peptidomics approach.

The online version contains supplementary material available at 10.1007/s10068-021-00998-6.

A Skate Skin Hydrolysate Restores Cognitive Function in 5XFAD Alzheimer Disease Mice Model by Suppressing Amyloid-β Accumulation via Upregulation of ERK-CREB

Alzheimer’s disease is a neurodegenerative disease hallmarked by gradual loss of neurons. The prevalence of such degenerative neuro-diseases has increased with an increase in the life expectancy especially as seen in developed countries. Amyloid-β (Aβ) is a chief intermediary for synaptic dysfunction and cognitive injury associated with Alzheimer's disease. However, the exact mechanism of the toxic effect of Aβ is still not entirely understood. Presently there is no known treatment for Alzheimer's disease. In this study, the effect of the long-term administration of SSH (skate skin neutrase hydrolysate) on Aβ associated cognitive impairment in an Alzheimer's disease mouse model (5XFAD mouse) was investigated. Investigation on cognitive function was measured using two behavioral tasks i.e. the Y-maze task and the Morris water maze task. The long term administration of SSH to 5XFAD mouse showed a marked behavioral improvement. 5XFAD mice that were treated with SSH showed minimal accumulation of Aβ. This implies SSH’s ability to prevent the accumulation of Aβ. In the group, the reduced activation of ERK-CREB (extracellular signal-regulated kinase-cAMP response element binding protein) was rescued by the treatment with SSH. It can be deduced that the activation of ERK-CREB is a major pathway through which SSH improves cognitive deficits observed in Alzheimer's disease.

Regulatory Effects of Skate Skin-Derived Collagen Peptides with Different Molecular Weights on Lipid Metabolism in the Liver and Adipose Tissue.

This study investigated the effects of skate skin collagen peptide (SSCP) with different molecular weights (MWs) on the lipid metabolism in the liver and adipose tissue. Male db/db mice were orally administered with water (control group) or low SSCP (LCP group) or high SSCP (HCP group) MW for 8 weeks whereas male m/m mice were used for comparison (normal group) (n = 10 each group). Compared to the control group, the LCP and HCP groups had lower adipose tissue mass, plasma and hepatic lipid concentrations, and plasma leptin levels (p < 0.05). Protein expression levels of lipogenesis-related protein were reduced in both liver and adipose tissues of SSCP-fed groups whereas those for lipolysis were elevated (p < 0.05). In particular, the LCP had the higher effects relative to the HCP. The above results were supported by histological analysis, revealing that SSCP administration decreased the size of adipose droplets and suppressed hepatic lipid accumulation. Our results showed that SSCP has potential antiobesity properties through the improvement of lipid metabolism in the liver and adipose tissue; in particular, the lower MW of collagen peptide had the greater effects.

Effect of Oral Ingestion of Low-Molecular Collagen Peptides Derived from Skate (Raja Kenojei) Skin on Body Fat in Overweight Adults: A Randomized, Double-Blind, Placebo-Controlled Trial.

Recent animal studies found the potential of a collagen peptide derived from skate skin to have anti-obesity effects through the suppression of fat accumulation and regulation of lipid metabolism. However, no studies have yet been performed in humans. Here, this very first human randomized, placebo-controlled, and double-blinded study was designed to investigate the efficacy and tolerability of skate skin collagen peptides (SCP) for the reduction of body fat in overweight adults. Ninety healthy volunteers (17 men) aged 41.2 ± 10.4 years with a mean body mass index of 25.6 ± 1.9 kg/m2 were assigned to the intervention group (IG), which received 2000 mg of SCP per day or to the control group (CG) given the placebo for 12 weeks and 81 (90%) participants completed the study. Changes in body fat were evaluated using dual energy X-ray absorptiometry as a primary efficacy endpoint. After 12 weeks of the trial, the percentage of body fat and body fat mass (kg) in IG were found to be significantly better than those of subjects in CG (−1.2% vs. 2.7%, p = 0.024 and −1.2 kg vs. 0.3 kg, p = 0.025). Application of SCP was well tolerated and no notable adverse effect was reported from both groups. These results suggest the beneficial potential of SCP in the reduction of body fat in overweight adults.

Effect of Skate Skin Extract on Cognitive Function in Adults

Effect of Skate Skin Extract on Cognitive Function in Adults

Anti-Obesity Effects of Collagen Peptide Derived from Skate (Raja kenojei) Skin Through Regulation of Lipid Metabolism.

This study investigated the anti-obesity effects of collagen peptide derived from skate skin on lipid metabolism in high-fat diet (HFD)-fed mice. All C57BL6/J male mice were fed a HFD with 60% kcal fat except for mice in the normal group which were fed a chow diet. The collagen-fed groups received collagen peptide (1050 Da) orally (100, 200, or 300 mg/kg body weight per day) by gavage, whereas the normal and control groups were given water (n = 9 per group). The body weight gain and visceral adipose tissue weight were lower in the collagen-fed groups than in the control group (p < 0.05). Plasma and hepatic lipid levels were significantly reduced by downregulating the hepatic protein expression levels for fatty acid synthesis (sterol regulatory element binding protein-1 (SREBP-1), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC)) and cholesterol synthesis (SREBP-2 and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR)) and upregulating those for β-oxidation (peroxisome proliferator-activated receptor alpha (PPAR-α) and carnitine palmitoyltransferase 1 (CPT1)) and synthesis of bile acid (cytochrome P450 family 7 subfamily A member 1 (CYP7A1)) (p < 0.05). In the collagen-fed groups, the hepatic protein expression level of phosphorylated 5′ adenosine monophosphate-activated protein kinase (p-AMPK) and plasma adiponectin levels were higher, and the leptin level was lower (p < 0.05). Histological analysis revealed that collagen treatment suppressed hepatic lipid accumulation and reduced the lipid droplet size in the adipose tissue. These effects were increased in a dose-dependent manner. The findings indicated that skate collagen peptide has anti-obesity effects through suppression of fat accumulation and regulation of lipid metabolism.

홍어 껍질 유래 콜라겐의 지방대사 조절을 통한 간 조직 지질축적 억제 효과

홍어의 가공과정 중 발생하는 부산물인 껍질에서 추출된 콜라겐의 비만 쥐에서 지질대사에 미치는 영향에 대해 알아보고자 하였다. 랩틴 수용체의 유전적 결핍으로 사육 기간에 따라 비만 및 당뇨가 유발되는 동물모델인 db/db mice에 홍어 껍질 유래 콜라겐을 200 mg/kg bw/d로 8주 동안 경구투여하였고(콜라겐 투여군), 그 효과를 정상군(m/m mice) 및 비만대조군(db/db mice)과 비교하였다. 실험 8주의 비만쥐의 체중은 정상군보다 유의적으로 증가하였고, 콜라겐 투여군에서 비만 쥐에 비해 48.8% 감소하였다. 그러나 비만군과 콜라겐군 사이의 식이섭취량의 차이는 나타나지 않았다. 혈액의 중성지질과 총콜레스테롤의 농도는 비만군에서 정상군보다 증가하였는데, 콜라겐을 경구 투여한 결과 혈중지질의 농도는 각각 24.1% 및 29.3% 유의적으로 감소하였다. 또한, 간 조직의 중성지질과 총콜레스테롤의 함량을 측정한 결과도 혈액에서의 결과와 유사한 경향을 나타내었다. 콜라겐을 급여한 결과 비만대조군에 비해 중성지질과 총콜레스테롤의 농도는 각각 26.0% 및 8.5% 감소하였다. 간에서 홍어 껍질 유래 콜라겐의 지질합성 및 분해와 관련된 대사작용에 미치는 영향을 western blotting 방법을 통해 확인하였다. 지방합성 및 대사작용의 핵심 인자인 SREBP-1, SREBP-2, FAS, ACCα 등이 정상 쥐보다 비만 쥐의 간 조직에서 단백질 발현이 유의적으로 증가하였고, 콜라겐을 투여한 군에서 감소하였다. 또한, 에너지 생산계의 하나인 지방산 베타산화 인자인 PPARα와 ACOX-1은 반대로 비만 쥐의 간 조직에서의 발현이 정상 쥐보다 감소하였는데, 콜라겐 투여군에서 유의적으로 증가하였다. 따라서 본 연구의 결과로 살펴보았을 때, 효소적 가수분해를 통해 얻은 홍어 껍질 유래 콜라겐을 비만 쥐에 경구 투여하였을 때 체중증가를 억제하고, 혈액과 간의 지질 농도를 감소시켰다. 이는 콜라겐이 간에서의 지질합성 관련 인자의 억제 및 지방산 분해를 촉진하는 대사과정을 조절하여 비만에서 지질대사를 개선할 것으로 생각한다.

Quality Characteristics of Skate Pipyun prepared with Skate Skin

Quality Characteristics of Skate Pipyun prepared with Skate Skin

Production and characterisation of skate skin gelatin films incorporated with thyme essential oil and their application in chicken tenderloin packaging

SummaryIn this study, skate skin gelatin (SSG) was used as a new biodegradable film source and a SSG film was prepared. In addition, thyme essential oil (TEO) was incorporated in the SSG film as an antimicrobial agent for the preparation of an antimicrobial film. The tensile strength (TS) of the film decreased, whereas elongation at break (E) increased by the addition of TEO. The SSG film containing TEO showed increased antimicrobial activity against Listeria monocytogenes and Escherichia coli O157:H7 as TEO concentration increased. To apply the SSG film to food packaging, chicken tenderloin samples were wrapped with the film containing 1% TEO. The packaging of chicken tenderloin with the TEO‐containing SSG film inhibited the growth of L. monocytogenes and E. coli O157:H7 compared to the control during storage. Therefore, the SSG film with added TEO has potential as active food packaging to extend the shelf life of chicken tenderloin.

Development of High Functional Collagen Peptide Materials using Skate Skins

The aim of this study was to investigate and development collagen peptide materials from skate skin. Protein and fat content of collagen peptide showed about 95% and 0.1%, respectively. Average molecular weight of collagen peptide was measured as 1,015. In the analysis of amino acid, glycine and hydroxy proline content in collagen peptide was 19.32% and 16.25%, respectively, showing a typical characteristics of the collagen peptide. In obese db/db mice ingested 500 mg/day of collagen peptide for 18 days, the amounts of food and water intake were decreased considerably, contents of triglyceride, total cholesterol were decreased significantly in white adipose tissue of db/db mice. The final yield of collagen peptide was 17.23% in the optimized process for mass production. These results indicate that collagen peptide from skate skin may serve as candidates of fat reduction in adipose tissue and could be used as functional food and cosmetic ingredients.

홍어껍질로 만든 홍어 피편의 품질 특성

홍어껍질로 만든 홍어 피편의 품질 특성

Angiotensin-I converting enzyme inhibitory peptides from antihypertensive skate (Okamejei kenojei) skin gelatin hydrolysate in spontaneously hypertensive rats

The aim of this study was to investigate antihypertensive effect of bioactive peptides from skate (Okamejei kenojei) skin gelatin. The Alcalase/protease gelatin hydrolysate below 1kDa (SAP) exhibited the highest angiotensin-I converting enzyme (ACE) inhibition compared to other hydrolysates. SAP can decrease systolic blood pressure significantly in spontaneously hypertensive rats. SAP inhibited vasoconstriction via PPAR-γ expression, activation and phosphorylation of eNOS in lungs. Moreover, the expression levels of endothelin-1, RhoA, α-smooth muscle actin, cleaved caspase 3 and MAPK were decreased by SAP in lungs. Vascularity, muscularization and cellular proliferation in lungs were detected by immunohistochemical staining. Finally, two purified peptides (LGPLGHQ, 720Da and MVGSAPGVL, 829Da) showed potent ACE inhibition with IC50 values of 4.22 and 3.09μM, respectively. These results indicate that bioactive peptides isolated from skate skin gelatin may serve as candidates against hypertension and could be used as functional food ingredients.

Characterization of β-secretase inhibitory peptide purified from skate skin protein hydrolysate

The objective of this study was to purify and characterize the β-secretase inhibitor from enzymatic hydrolysates of skate skin, for the development of a novel antidementia agent that may be utilized in the drug or functional food industries. β-secretase inhibitory peptide was purified from various enzymatic hydrolysates of skate skin. Among six enzymatic hydrolysates, the Neutrase hydrolysate showed the highest β-secretase inhibitory activity. Consecutive purification of the skate skin hydrolysate using Sephadex G-25 column chromatography and octadecylsilane C18 reversed phase HPLC techniques was used to isolate a potent β-secretase inhibitory peptide composed of 12 amino acids, Gln–Gly–Try–Arg–Pro–Leu–Arg–Gly–Pro–Glu–Phe–Leu (MW: 1,391 Da). The purified peptide had strong β-secretase inhibitory activity, with IC50 value of 24.26 μM, and displayed a non-competitive mode of inhibition. Among the synthesized β-secretase inhibitory peptides, the tetrapeptide Pro–Glu–Phe–Leu had the highest β-secretase inhibitory activity. The result of this study suggests that the β-secretase inhibitory peptide derived from skate skin could be potential candidates to develop nutraceuticals and pharmaceuticals.

Protective effects of peptides from skate (Okamejei kenojei) skin gelatin against endothelial dysfunction

Seafood processing by-product, skate (Okamejei kenojei) skin, was utilized to isolate active peptides with antihypertensive effect. Two peptides (MVGSAPGVL, 829 Da and LGPLGHQ, 720 Da) were purified from skate skin gelatin. In human endothelial cells, nitric oxide (NO) synthesis was found to be increased and eNOS phosphorylation was upregulated by the peptides. The peptides exhibited inhibitory activities on the production and expression of IL-6. Furthermore, the peptides down-regulated the expression levels of endothelin-1. The peptides inhibited the NF-κB and the phosphorylation of MAPK pathways. In addition, the activation of the PI3K/Akt pathway by the peptides was confirmed. The present study demonstrated that the purified peptides had vasorelaxant effects via endothelium-dependent NO signaling through activation of the PI3K/Akt-eNOS pathway and inhibition of the NF-κB and MAPK pathways. The purified peptides could be used in the food industry as functional ingredients with potent benefits in reducing the risk of cardiovascular diseases.

Active peptides from skate (Okamejei kenojei) skin gelatin diminish angiotensin-I converting enzyme activity and intracellular free radical-mediated oxidation

Skin gelatin of skate (Okamejei kenojei) was hydrolyzed using Alcalase, flavourzyme, Neutrase and protamex. It was found that the Alcalase hydrolysate exhibited the highest angiotensin-I converting enzyme (ACE) inhibitory activity. Then, Alcalase hydrolysate was further hydrolyzed with protease and separated by an ultrafiltration membrane system. Finally, two peptides responsible for ACE inhibitory activity were identified to be MVGSAPGVL (829Da) and LGPLGHQ (720Da), with IC50 values of 3.09 and 4.22μM, respectively. Moreover, the free radical-scavenging activity of the purified peptides was determined in human endothelial cells. In addition, the antioxidative mechanism of the purified peptides was evaluated by protein and gene expression levels of antioxidant enzymes. The current study demonstrated that the peptides derived from skate skin gelatin could be used in the food industry as functional ingredients with potent antihypertensive and antioxidant benefits.