Beneficial effects of natural eggshell membrane (NEM) on multiple indices of arthritis in collagen-induced arthritic rats

Could eggshell membrane be an adjuvant for recombinant Hepatitis B vaccine?: A preliminary investigation

Background

Despite the invasiveness of the Hepatitis B infection, its vaccines are only formulated with FDA-approved alum-based adjuvants, which poorly elicit a lasting immune response, hence the need for a more effective adjuvant system. This study evaluated the immunogenicity and toxicity of eggshell membranes (ESM) when administered as an adjuvant for the recombinant HBV vaccine (rHBsAg) in albino mice. Differential white blood cell analysis, as well as the titer measurement of Immunoglobulin G, subclass G1 and G2a on indirect ELISA, was performed to measure the immune-modulatory potentials of ESM. Moreover, analysis of the liver marker enzyme (AST and ALT) and body/liver weights was performed to ascertain the toxicity level of ESM. Finally, Immuno-informatic analysis was used to investigate the immune-modulatory potential of individual member proteins of ESM.

Results

Our results showed a significant improvement in the experimental group's lymphocyte count after boost-dose administration compared to the controls, whereas there was no significant change in the granulocyte population. Furthermore, the formulations (ESM-rHBsAg) significantly improved IgG and IgG1 titers after each successive immunization. Body/liver weight and liver function showed ESM non-toxic to mice. The immunoinformatic analysis discovered ovalbumin, lysozyme-C, and UFM-1 as the member proteins of ESM with immune-modulatory activities of activating antigen-presenting cells (APC).

Conclusion

This study has provided a clue into the potential valorization of eggshell membranes and their peptides as an adjuvant for vaccines such as HBV. We recommend more in-depth molecular analysis to support our findings as well as foster real-life application.

Supplementary Information

The online version contains supplementary material available at 10.1186/s43094-023-00481-5.

Health Functions of Egg Protein

Egg protein is a remarkably abundant source of protein, with an amino acid score of 100 and the highest net protein utilization rate. However, there have been relatively fewer studies investigating the health benefits of egg protein. In this review, we have summarized the available information regarding the health benefits of egg proteins based on human studies. In particular, studies conducted on the characteristics of egg whites, as they are high in pure protein, have reported their various health functions, such as increases in muscle mass and strength enhancement, lowering of cholesterol, and visceral fat reduction. Moreover, to facilitate and encourage the use of egg white protein in future, we also discuss its health functions. These benefits were determined by developing an egg white hydrolysate and lactic-fermented egg whites, with the latter treatment simultaneously improving the egg flavor. The health benefits of the protein hydrolysates from the egg yolk (bone growth effect) and eggshell membrane (knee join pain-lowering effect) have been limited in animal studies. Therefore, the consumption of egg protein may contribute to the prevention of physical frailty and metabolic syndromes.

High value applications and current commercial market for eggshell membranes and derived bioactives

Chicken eggshell membrane (ESM) is a highly insoluble structure that is greatly stabilized by extensive desmosine, isodesmosine, and disulfide cross-linkages. The ESM possesses numerous biological functions including anti-microbial, anti-inflammatory, anti-wrinkle, and antioxidant activities. The ESM is mainly proteinaceous; proteomics and bioinformatics analysis of ESM has identified > 500 proteins, such as collagens, glycoproteins, avian beta-defensins, and lysozyme. ESM also contains significant amounts of carbohydrate, including hyaluronic acid (HA). In general, HA plays an important role in tissue hydration and cellular mechanisms such as growth, differentiation, and transport, and has diverse health and medical applications. Despite ESM being rich in important bioactive compounds, it is often considered as a waste product of the egg-breaking industry and is under-utilized. A major challenge for the successful commercial exploitation of ESM and bioactive constituents is its limited solubility and bioavailability due to cross-linkages of ESM fibers. Various processing and extraction methods are employed to overcome these limitations and improve the production of HA and collagen-based ESM formats. Moreover, we believe that there is a wide scope to exploit ESM for novel applications, leading to new intellectual property (IP) and patenting opportunities. This review presents an overview of scientific background, IP landscape and current commercial market for ESM and derived bioactives including collagens and HA. A detailed literature survey is provided for each area of interest. We analyze regulatory guidelines for ESM, contrasting quality control / microbial safety assessment in cosmetics and personal care products (hazard based) with that of the food industry (risk-based). New perspectives for upcycling of ESM waste to commercially viable high-value biomaterials as nutraceutical supplements and as cosmetics ingredients are discussed. This overview of ESM separation techniques and applications could form the basis for directed research and product development in order to exploit the unique bioactivities of ESM.

Eggshell Membrane Ameliorates Hyperuricemia by Increasing Urate Excretion in Potassium Oxonate-Injected Rats

Hyperuricemia is the primary cause of gouty arthritis and other metabolic disorders. Eggshell membrane (EM) is an effective and safe supplement for curing pain and stiffness connected with osteoarthritis. However, the effect of EM on hyperuricemia is unclear. This study determines the effects of EM on potassium oxonate-injected hyperuricemia. Uric acid, creatinine, blood urea nitrogen concentrations in the serum, and xanthine oxidase activity in the liver are measured. Protein levels of renal urate transporter 1 (URAT1), organic anion transporters 1 (OAT1), glucose transporter 9 (GLUT9), and ATP-binding cassette transporter G2 (ABCG2) in the kidney are determined with renal histopathology. The results demonstrate that EM reduces serum uric acid levels and increases urine uric acid levels in hyperuricemic rats. Moreover, EM downregulates renal URAT1 protein expression, upregulates OAT1 and ABCG2, but does not change GLUT9 expression. Additionally, EM does not change xanthine oxidase activity in the liver or the serum. EM also decreases uric acid uptake into oocytes expressing hURAT1. Finally, EM markedly reduces renal inflammation and serum interleukin-1β levels. These findings suggest that EM exhibits antihyperuricemic effects by promoting renal urate excretion and regulating renal urate transporters. Therefore, EM may be useful in the prevention and treatment of gout and hyperuricemia.

Avian Eggshell Membrane as a Novel Biomaterial: A Review

The eggshell membrane (ESM), mainly composed of collagen-like proteins, is readily available as a waste product of the egg industry. As a novel biomaterial, ESM is attractive for its applications in the nutraceutical, cosmetic, and pharmaceutical fields. This review provides the main information about the structure and chemical composition of the ESM as well as some approaches for its isolation and solubilization. In addition, the review focuses on the role and performance of bioactive ESM-derived products in various applications, while a detailed literature survey is provided. The evaluation of the safety of ESM is also summarized. Finally, new perspectives regarding the potential of ESM as a novel biomaterial in various engineering fields are discussed. This review provides promising future directions for comprehensive application of ESM.

Lipoxin A4-Mediated p38 MAPK Signaling Pathway Protects Mice Against Collagen-Induced Arthritis

The aim of the article was to study the mechanism of Lipoxin A4 (LXA4)-mediated p38 MAPK pathway protecting mice against collagen-induced arthritis (CIA). The impact of LXA4 (0, 5, 10, 15 nM) on synoviocytes proliferation of CIA mice was detected using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. CIA mice were treated with LXA4, SB203580 (a p38 inhibitor), and/or anisomycin (a p38 agonist), and the arthritis severity score in each mouse was determined. The gene or protein expressions were detected with Western Blotting, ELISA, or qRT-PCR. LXA4 inhibited the synoviocytes proliferation of CIA mice with decreased levels of TNF-α, IL-6, IL-1β, and IFN-γ and reduced p-p38/total p38 expression in synoviocytes in a dose-dependent manner. LXA4 levels were decreased in synovial tissues and plasma of CIA mice, but p-p38/total p38 expression was increased in synovial tissues. LXA4 could downregulate p-p38/total p38 expression in synovial tissues of CIA mice. Both LXA4 and SB203580 reduced arthritis severity score of CIA mice with the reduction of synovial tissue hyperplasia and inflammatory cell infiltration. CIA mice treated with LXA4 and SB203580 had lower levels of TNF-α, IL-6, IL-1β, and IFN-γ, accompanying decreased MDA as well as increased SOD, CAT,and GPx. However, anisomycin could reverse the protect effects of LXA4 on CIA mice regarding the abovementioned inflammatory factors and oxidative stress indexes. LXA4 protected mice against collagen-induced arthritis via inhibiting p38 MAPK signaling pathway, which may be a potential new therapeutic target for rheumatoid arthritis.

Clinical applications of avian eggshell-derived hydroxyapatite

The search for bone reconstruction materials and methods is an ongoing challenge. The aim of this review is to systemically search the available literature concerning the clinical performance of eggshell as a substitute material in guided bone regeneration in oral surgery. Five databases (PubMed, Cochrane, Web of Science, Scopus, and Embase) were searched up to February 2020. Clinical trials that used eggshell as a bone substitute material were included in the review. Animal and in vivo studies were excluded from the review. ROBINS-I was used to evaluate the risk of bias. A total of 840 studies were retrieved, out of which 55 full-text articles were screened. Five studies were finally included: one study showed critical and four serious risk of bias. A total of 74 patients and 88 intervention sites were included in the five studies. Clinical and radiological evaluation showed complete healing during the follow-ups. Statistically significant radiological and clinical evidence of new bone formation was achieved for socket preservation, grafting after third molar extraction, and cystic/apicectomy grafting. One patient with complications was reported. Histological analysis and micro computed tomography confirmed that it promotes bone regeneration. A comparison with synthetic hydroxyapatite showed similar healing characteristics. Within the limitations of the included studies, the eggshell can be safely and efficiently used in guided bone regeneration procedures, but more research is needed to completely evaluate the full potential of this material.

A novel eco-friendly green approach to produce particalized eggshell membrane (PEM) for skin health applications

The eggshell membrane (ESM) is a natural bioactive material, which is increasingly utilized for various biomedical applications. However, the poor solubility of ESM limits the bioavailability of its constituents and reduces the expression of their potential bioactivity. In this study, we utilized an innovative green strategy to separate ESM from shell, and processed ESM for size reduction by cryo-grinding and homogenization to produce particalized eggshell membrane (PEM) approaching submicron dimensions, with enhanced anti-inflammatory activity and increased antimicrobial activity against skin associated pathogens. Gram-positive Staphylococcus aureus (log₁₀ reduction = 4.5 ± 0.3) was more sensitive to PEM as compared to Gram-negative Pseudomonas aeruginosa (log₁₀ reduction = 2.1 ± 0.3). PEM elicited a dose-dependent reduction in NO accumulation in LPS-induced RAW 264.7 macrophages, suggesting an anti-inflammatory response to ESM particles. These findings suggest that processed PEM possesses great potential as a topical ingredient in skincare applications to maintain skin health by reducing bacterial infections and inflammation.

Mildly Processed Natural Eggshell Membrane Alleviates Joint Pain Associated with Osteoarthritis of the Knee: A Randomized Double-Blind Placebo-Controlled Study

Poor joint health is a significant burden to society. Millions of people suffer from some form of joint-related disorder or disease, most often osteoarthritis (OA). It was hypothesized that chicken eggshell membrane (EM) is effective in the regeneration of cartilage and/or immunomodulation (oral tolerance), and as such relieves pain and stiffness in joints commonly affected in arthritis. We tested this hypothesis in a double-blind, placebo-controlled EM intervention study. Of 150 male and female volunteers, 40-75 years of age and diagnosed with knee OA, 75 were randomly assigned to the EM intervention group and 75 to the placebo group. During 12 weeks, subjects received a daily capsule containing either 300 mg of EM or a placebo. The main primary dependent variable consisted of self-reported pain ratings on a Numerical Rating Scale Pain (NRS-P) 6 weeks after study start. As secondary dependent variables served NRS-P scores collected after 12 weeks, and Knee injury and self-reported Osteoarthritis Outcome Scores (Knee injury and Osteoarthritis Outcome Scores [KOOS]). NRS-P scores decreased for both groups at approximately the same rate, but only EM relieved self-reported pain scores obtained with the KOOS questionnaire starting 1 week after initiation of treatment. This effect was significant for two of five KOOS category scores, that is, "Pain" and "Daily Life" functioning, aggregate pain, and functioning scores composed of complaint ratings for a wide variety of daily activities. These scores showed long-lasting improvement, and demonstrated that EM extract successfully reliefs knee OA pain and contributes to daily life functioning.

Microparticles-in-Thermoresponsive/Bioadhesive Hydrogels as a Novel Integrated Platform for Effective Intra-articular Delivery of Triamcinolone Acetonide

Intra-articular (IA) injection of thermoresponsive hydrogels coupled with microparticles (MPs) possess the benefit of sustaining the anti-inflammatory drug effect within the joint cavity for rheumatoid arthritis treatment. Star-shaped thermoresponsive poly(polyethylene glycol) methacrylate [Poly(PEGMA)] copolymers were synthesized using free radical polymerization technique and fully characterized. Triamcinolone acetonide (TA)-loaded PLA/mPEG-PDL MPs, previously optimized, were integrated into the synthesized copolymer solutions at various concentrations and tested for their gelation temperatures. The MPs-in-hydrogel formulations were characterized using scanning electron microscope (SEM), viscosity measurements, ex vivo bioadhesion, and in vitro release studies. The anti-inflammatory effect of integrated systems was assessed in adjuvant-induced monoarthritic rat knee joints and compared to Kenacort and TA-loaded MPs. Two copolymers were successfully synthesized; G-1 = poly(PEGMA₁₈₈-ME-co-PEGMA₄₇₅-ME) and G-2 = poly(PEGMA₂₄₆-EE-co-PEGMA₄₇₅-ME). Using the tube inversion technique, the gel formation was found dependent on copolymer concentration. An irreversible aggregation was obtained at copolymer concentrations ≤10% (w/v), while a gel was formed at 20 and 30% (w/v) of both copolymers upon increasing temperature. The MP-hydrogel formulations were optimized at 20 and 30% (w/v) of G-1 and G-2 with gelation temperatures of 33 and 37 °C, respectively. SEM images revealed the porous microstructures of hydrogels and their adsorption on MP surfaces. The integrated formulas showed pseudoplastic behaviors, while the bioadhesion study confirmed their bioadhesiveness on excised cartilage. The in vitro release study confirmed drug sustainment from MPs-hydrogels compared to MPs. In vivo studies proved the superiority of MP-in-hydrogels in treatment of induced arthritis, relative to Kenacort and MPs alone, suggesting the applicability of this integrated platform in IA drug delivery.

Separation and Identification of Highly Efficient Antioxidant Peptides from Eggshell Membrane

The enzymatic hydrolysates (EHs) of the eggshell membrane (ESM) were obtained after incubating eggshell membrane in solutions prepared with Na₂SO₃ and alkaline protease combinations. The effects of enzyme species, enzyme dosage, Na₂SO₃ concentration, and hydrolysis time on the antioxidant activity of the ESM-EH were determined. Also, the correlation between the degree of hydrolysis (DH) and the antioxidant activity of ESM-EH was analyzed. The DH of ESM-EH showed a highly positive correlation with the reducing power (R² = 0.857) and total antioxidant activity (TAA) (R² = 0.876) and performed negative correlation with the Fe²⁺-chelating ability (R² = −0.529). The molecular weight distribution of the ESM-EH was determined by MALDI-TOF/MS. Cation exchange chromatography (Sephadex C-25) was used to isolate the ESM-EH and then the enzymatic hydrolysis fragment (EHF) was obtained. Among the five isolated fragments (F1~F5), fragment 3 (F3), which was composed of 28 polypeptides, showed the highest ability to quench ABTS• (2,2-azinobis-3-ethyl-benzothiazoline-6-sulfonic acid) (90.44%) and also displayed stronger TBARS (thiobarbituric acid– reactive substances) (58.17%) and TAA (303.82 µg /mL) than the ESM-EH. Further analysis of the 28 peptides in F3 identified using LC-MS/MS indicated that five peptides (ESYHLPR, NVIDPPIYAR, MFAEWQPR, LLFAMTKPK, MLKMLPFK) showed high water-solubility, biological activities, and antioxidant characteristics. Finally, the TAA of the synthetic peptide was verified, the synthetic peptides ESYHLPR and MFAEWQPR performed the best activity and have high potentials to be used as antioxidant agents in functional foods, pharmaceuticals, or cosmetics.

Triamcinolone acetonide-loaded PLA/PEG-PDL microparticles for effective intra-articular delivery: synthesis, optimization, in vitro and in vivo evaluation

Nowadays the use of sustainable polymers as poly-lactic acid (PLA) and poly-δ-decalactone (PDL) in drug delivery is advantageous compared to polymers derived from fossil fuels. The present work aimed to produce microparticles (MPs) derived from novel sustainable polymers, loaded with triamcinolone acetonide (TA) for treatment of rheumatoid arthritis via intra-articular (IA) delivery. PDL was synthesized from green δ-decalactone monomers and co-polymerized with methoxy-polyethylene glycol (mPEG) forming PEG-PDL with different molecular weights. The Hansen's solubility parameters were applied to select the most compatible polymer with the drug. An o/w emulsion/solvent evaporation technique was used for MPs fabrication, using 3 [3] full factorial design. Selection of the optimized MPs was performed using Expert Design® software's desirability function. The optimized formulations were characterized using scanning electron microscope, powder X-ray diffraction, differential scanning calorimetry, infrared spectroscopy and in vitro release studies. The inhibition percents of inflammation and histopathological studies were assessed in complete Freund's adjuvant-induced rats' knee joints evaluating the effect of IA injections of selected MPs compared to the free drug suspension. Solubility studies revealed high compatibility and miscibility between TA and PEG-PDL₁₇₀₀, which was blended with PLA for convenient MPs formation. The in vitro characterization studies confirmed the formation of drug-copolymer co-crystals. The in vivo studies ensured the superiority of the newly designed composite MPs in inflammation suppression, compared to the free drug suspension and PLA MPs as well. The present study proved the advantage of using sustainable polymers in a novel combination for effective drug delivery and suggesting its usefulness in designing versatile platforms for therapeutic applications.

Eggshell membrane protein can be absorbed and utilised in the bodies of rats

Objective

Eggshell membranes, the thin film lining the insides of eggshells, are constituted mostly from protein (eggshell membrane protein, ESM-P). The digestibility and dietary net protein utility of ESM-P are not known. ESM-P functions as a barrier to prevent foreign matter from reaching the egg white and yolk, so it would be expected not to decompose easily by digestion when ingested. We therefore prepared a hydrolysate of the membrane (ESM-H). In this study, we assessed the digestibility and net protein utility of ESM-P and ESM-H in rats.

Results

The digestibility of ESM-P and ESM-H were 87.0% and 94.8%, respectively, significantly lower than that of casein (98.5%). The net protein utility values were 84.7% and 84.6%, respectively, significantly higher than that of casein (75.1%). Digestibility was significantly higher for ESM-H than for ESM-P, but there was no significant difference in net protein utility between ESM-P and ESM-H. These results demonstrated that more than 80% of ESM-P or ESM-H is absorbed and utilised in the bodies of rats.

Expression levels of IL-15 and IL-17 in synovial fluid of rheumatoid arthritis animal model

The aim of the present study was to investigate the expression levels of interleukin-15 (IL-15) and interleukin-17 (IL-17) in synovial fluid of rheumatoid arthritis (RA) animal model, and to investigate their correlations with RA. A total of 100 Wistar rats were selected, among which 60 rats were used to establish the collagen II-induced arthritis (CIA) model as the model observation group, and the remaining 40 rats were used as blank control group. The levels of IL-15 and IL-17 in synovial fluid were detected via enzyme-linked immunosorbent assay (ELISA) at 1, 7, 14, 21 and 28 days after successful modeling. RA was evaluated by using arthritis index (AI) and pedal swelling volume. The expression levels of IL-15 and IL-17 in synovial fluid of rats in model observation group were higher than those in blank control group (P<0.05), and the levels of IL-15 and IL-17 in model observation group were gradually increased over time. In model observation group at 7 days after modeling, AI and pedal swelling volume began to be increased gradually reaching a peak at 28 days. The pedal swelling volume of CIA model rats was significantly higher than that of the blank control group (P<0.05). The increased expression levels of IL-15 and IL-17 in synovial fluid of rats in the CIA model observation group are correlated with the activity of disease, which can be used as reference indexes for the activity of RA.

Beneficial effects of natural eggshell membrane versus placebo in exercise-induced joint pain, stiffness, and cartilage turnover in healthy, postmenopausal women

PURPOSE

Despite its many health benefits, moderate exercise can induce joint discomfort when done infrequently or too intensely even in individuals with healthy joints. This study was designed to evaluate whether NEM® (natural eggshell membrane) would reduce exercise-induced cartilage turnover or alleviate joint pain or stiffness, either directly following exercise or 12 hours post exercise, versus placebo.

PATIENTS AND METHODS

Sixty healthy, postmenopausal women were randomly assigned to receive either oral NEM 500 mg (n=30) or placebo (n=30) once daily for two consecutive weeks while performing an exercise regimen (50-100 steps per leg) on alternating days. The primary endpoint was any statistically significant reduction in exercise-induced cartilage turnover via the biomarker C-terminal cross-linked telopeptide of type-II collagen (CTX-II) versus placebo, evaluated at 1 and 2 weeks of treatment. Secondary endpoints were any reductions in either exercise-induced joint pain or stiffness versus placebo, evaluated daily via participant questionnaire. The clinical assessment was performed on the per protocol population.

RESULTS

NEM produced a significant absolute treatment effect (TEabs) versus placebo for CTX-II after both 1 week (TEabs -17.2%, P=0.002) and 2 weeks of exercise (TEabs -9.9%, P=0.042). Immediate pain was not significantly different; however, rapid treatment responses were observed for immediate stiffness (Day 7) and recovery pain (Day 8) and recovery stiffness (Day 4). No serious adverse events occurred and the treatment was reported to be well tolerated by study participants.

CONCLUSION

NEM rapidly improved recovery from exercise-induced joint pain (Day 8) and stiffness (Day 4) and reduced discomfort immediately following exercise (stiffness, Day 7). Moreover, a substantial chondroprotective effect was demonstrated via a decrease in the cartilage degradation biomarker CTX-II. Clinical Trial Registration number: NCT02751944.