Potential of Atlantic Codfish (Gadus morhua) Skin Collagen for Skincare Biomaterials

Collagen is the major structural protein in extracellular matrix present in connective tissues, including skin, being considered a promising material for skin regeneration. Marine organisms have been attracting interest amongst the industry as an alternative collagen source. In the present work, Atlantic codfish skin collagen was analyzed, to evaluate its potential for skincare. The collagen was extracted from two different skin batches (food industry by-product) using acetic acid (ASColl), confirming the method reproducibility since no significant yield differences were observed. The extracts characterization confirmed a profile compatible with type I collagen, without significant differences between batches or with bovine skin collagen (a reference material in biomedicine). Thermal analyses suggested ASColl's native structure loss at 25 °C, and an inferior thermal stability to bovine skin collagen. No cytotoxicity was found for ASColl up to 10 mg/mL in keratinocytes (HaCaT cells). ASColl was used to develop membranes, which revealed smooth surfaces without significative morphological or biodegradability differences between batches. Their water absorption capacity and water contact angle indicated a hydrophilic feature. The metabolic activity and proliferation of HaCaT were improved by the membranes. Hence, ASColl membranes exhibited attractive characteristics to be applied in the biomedical and cosmeceutical field envisaging skincare.

Marine Gelatin-Methacryloyl-Based Hydrogels as Cell Templates for Cartilage Tissue Engineering

Marine-origin gelatin has been increasingly used as a safe alternative to bovine and porcine ones due to their structural similarity, avoiding the health-related problems and sociocultural concerns associated with using mammalian-origin materials. Another benefit of marine-origin gelatin is that it can be produced from fish processing-products enabling high production at low cost. Recent studies have demonstrated the excellent capacity of gelatin-methacryloyl (GelMA)-based hydrogels in a wide range of biomedical applications due to their suitable biological properties and tunable physical characteristics, such as tissue engineering applications, including the engineering of cartilage. In this study, fish gelatin was obtained from Greenland halibut skins by an acidic extraction method and further functionalized by methacrylation using methacrylic anhydride, developing a photosensitive gelatin-methacryloyl (GelMA) with a degree of functionalization of 58%. The produced marine GelMA allowed the fabrication of photo-crosslinked hydrogels by incorporating a photoinitiator and UV light exposure. To improve the biological performance, GelMA was combined with two glycosaminoglycans (GAGs): hyaluronic acid (HA) and chondroitin sulfate (CS). GAGs methacrylation reaction was necessary, rendering methacrylated HA (HAMA) and methacrylated CS (CSMA). Three different concentrations of GelMA were combined with CSMA and HAMA at different ratios to produce biomechanically stable hydrogels with tunable physicochemical features. The 20% (w/v) GelMA-based hydrogels produced in this work were tested as a matrix for chondrocyte culture for cartilage tissue engineering with formulations containing both HAMA and CSMA showing improved cell viability. The obtained results suggest these hybrid hydrogels be used as promising biomaterials for cartilage tissue engineering applications.

Cell-Laden Marine Gelatin Methacryloyl Hydrogels Enriched with Ascorbic Acid for Corneal Stroma Regeneration

Corneal pathologies from infectious or noninfectious origin have a significant impact on the daily lives of millions of people worldwide. Despite the risk of organ rejection or infection, corneal transplantation is currently the only effective treatment. Finding safe and innovative strategies is the main goal of tissue-engineering-based approaches. In this study, the potential of gelatin methacryloyl (GelMA) hydrogels produced from marine-derived gelatin and loaded with ascorbic acid (as an enhancer of the biological activity of cells) was evaluated for corneal stromal applications. Marine GelMA was synthesized with a methacrylation degree of 75%, enabling effective photocrosslinking, and hydrogels with or without ascorbic acid were produced, encompassing human keratocytes. All the produced formulations exhibited excellent optical and swelling properties with easy handling as well as structural stability and adequate degradation rates that may allow proper extracellular matrix remodeling by corneal stromal cells. Formulations loaded with 0.5 mg/mL of ascorbic acid enhanced the biological performance of keratocytes and induced collagen production. These results suggest that, in addition to marine-derived gelatin being suitable for the synthesis of GelMA, the hydrogels produced are promising biomaterials for corneal regeneration applications.

Marine collagen-chitosan-fucoidan cryogels as cell-laden biocomposites envisaging tissue engineering

The combination of marine origin biopolymers for tissue engineering (TE) applications is of high interest, due to their similarities with the proteins and polysaccharides present in the extracellular matrix of different human tissues. This manuscript reports on innovative collagen-chitosan-fucoidan cryogels formed by the simultaneous blending of these three marine polymers in a chemical-free crosslinking approach. The physicochemical characterization of marine biopolymers comprised FTIR, amino acid analysis, circular dichroism and SDS-PAGE, and suggested that the jellyfish collagen used in the cryogels was not denatured (preserved the triple helical structure) and had similarities with type II collagen. The chitosan presented a high deacetylation degree (90.1%) that can strongly influence the polymer physicochemical properties and biomaterial formation. By its turn, rheology, and SEM studies confirmed that these novel cryogels present interesting properties for TE purposes, such as effective blending of biopolymers without visible material segregation, mechanical stability (strong viscoelastic character), as well as adequate porosity to support cell proliferation and exchange of nutrients and waste products. Additionally, in vitro cellular assessments of all cryogel formulations revealed a non-cytotoxic behavior. The MTS test, live/dead assay and cell morphology assessment (phalloidin DAPI) showed that cryogels can provide a proper microenvironment for cell culturing, supporting cell viability and promoting cell proliferation. Overall, the obtained results suggest that the novel collagen-chitosan-fucoidan cryogels herein presented are promising scaffolds envisaging tissue engineering purposes, as both acellular biomaterials or cell-laden cryogels.

Interval colorectal cancer after colonoscopy

INTRODUCTION AND AIMS

Interval colorectal cancer (iCRC) can occur due to missed lesions or to a newly developed lesion. The present study aimed to assess the iCRC rate and its characteristics in our population and find possible explanations.

MATERIALS AND METHODS

A retrospective study was conducted on patients with colorectal cancer (CRC) diagnosed between January 2011 and January 2015 at our department. Demographics, endoscopic data, and tumor characteristics (location, histology, staging) were collected. We identified patients diagnosed with CCR who underwent colonoscopy at our department in the previous 10years and presented the disease (iCRC) before the date of their next recommended exam. The cases of iCRC were characterized and compared with other CRC cases. Possible explanations for the appearance of iCRC were analyzed.

RESULTS

A total of 266 patients presented with CRC, 61.7% were men, and mean patient age was 70.7years. We identified 10 patients with iCRC: 6 were men, and mean patient age was 71.1years. Mean time for iCRC diagnosis after index colonoscopy was 3.5±1.84years. Tumor was located in the right colon in 50% of the patients with iCRC and in 24.5% of the patients without iCRC (P=.091). More patients with iCRC had a family history of CRC (50%) than the patients with reference CRC (3.1%) (P=.000).

CONCLUSIONS

In our case series, 3.76% of all CRC were iCRC. There were no statistically significant differences between patients with or without iCRC, with the exception of family history of CRC.

Fast plasma sintering delivers functional graded materials components with macroporous structures and osseointegration properties

We explored the osseointegration potential of two macroporous titanium surfaces obtained using fast plasma sintering (FPS): Ti macroporous structures with 400-600 µmØ pores (TiMac400) and 850-1000 µmØ pores (TiMac850). They were compared against two surfaces currently in clinical use: Ti-Growth® and air plasma spray (Ti-Y367). Each surface was tested, once placed over a Ti-alloy and once onto a CoCr bulk substrate. Implants were placed in medial femoral condyles in 24 sheep. Samples were explanted at four and eight weeks after surgery. Push-out loads were measured using a material-testing system. Bone contact and ingrowth were assessed by histomorphometry and SEM and EDX analyses. Histology showed early osseointegration for all the surfaces tested. At 8 weeks, TiMac400, TiMac850 and Ti-Growth® showed deep bone ingrowth and extended colonisation with newly formed bone. The mechanical push-out force was equal in all tested surfaces. Plasma spray surfaces showed greater bone-implant contact and higher level of pores colonisation with new bone than FPS produced surfaces. However, the void pore area in FPS specimens was significantly higher, yet the FPS porous surfaces allowed a deeper osseointegration of bone to implant. FPS manufactured specimens showed similar osseointegration potential to the plasma spray surfaces for orthopaedic implants. FPS is a useful technology for manufacturing macroporous titanium surfaces. Furthermore, its capability to combine two implantable materials, using bulk CoCr with macroporous titanium surfaces, could be of interest as it enables designers to conceive and manufacture innovative components. FPS delivers functional graded materials components with macroporous structures optimised for osseointegration.

Metabolic syndrome and colorectal neoplasms: An ominous association

AIM: To evaluate the association of metabolic syndrome (MS) and colorectal cancer and adenomas in a Western country, where the incidence of MS is over 27%.

METHODS: This was a prospective study between March 2013 and March 2014. MS was diagnosed according to the National Cholesterol Education Program-ATP III. Demographic characteristics, anthropometric measurements, metabolic risk factors, and colonoscopic pathologic findings were assessed in patients with MS (group 1) who underwent routine colonoscopy at our department. This data was compared with consecutive patients without metabolic syndrome (group 2), with no differences regarding sex and age. Patients with incomplete colonoscopy, family history, or past history of colorectal neoplasm were excluded. Informed consent was obtained and the ethics committee approved this study. Statistical analysis was performed using Student’s t-test and χ² test, with a P value ≤ 0.05 being considered statistically significant.

RESULTS: Of 258 patients, 129 had MS; 51% males; mean-age 67.1 years (50-87). Among the MS group, 94% had high blood pressure, 91% had increased waist circumference, 60% had diabetes, 55% had low high-density lipoprotein cholesterol level, 50% had increased triglyceride level, and 54% were obese [body mass index (BMI) 30 kg/m²]. 51% presented 4 criteria of MS. MS was associated with increased prevalence of adenomas (43% vs 25%, P = 0.004) and colorectal cancer (13% vs 5%, P = 0.027), compared with patients without MS. MS was also positively associated with multiple (≥ 3) adenomas (35% vs 9%, P = 0.024) and sessile adenomas (69% vs 53%, P = 0.05). No difference existed between location (P = 0.086), grade of dysplasia (P = 0.196), or size (P = 0.841) of adenomas. In addition, no difference was found between BMI (P = 0.078), smoking (P = 0.146), alcohol consumption (P = 0.231), and the presence of adenomas.

CONCLUSION: MS is positively associated with adenomas and colorectal cancer. However, there is not enough information in western European countries to justify screening in patients with MS. To our knowledge, no previous study has evaluated this association in Portuguese patients.

Appropriateness of outpatient gastrointestinal endoscopy in a non-academic hospital

AIM: To assess the appropriate use and the diagnostic yield of upper gastrointestinal endoscopy and colonoscopy in this subgroup of patients.

METHODS: In total, 789 consecutive outpatients referred for gastrointestinal (GI) endoscopy [381 for esophagogastroduodenoscopy (EGD) and 408 for colonoscopy] were prospectively enrolled in the study. The American Society for Gastrointestinal Endoscopy (ASGE) guidelines were used to assess the relationship between appropriateness and the presence of relevant endoscopic findings.

RESULTS: The overall inappropriate rate was 13.3%. The indications for EGD and colonoscopy were, respectively, appropriate in 82.7% and 82.6% of the exams, uncertain in 5.8% and 2.4% and inappropriate in 11.5% and 15%. The diagnostic yield was significant higher for EGDs and colonoscopies judged appropriate and uncertain when compared with those considered inappropriate (EGD: 36.6% vs 36.4% vs 11.4%, P = 0.004; Colonoscopy: 24.3% vs 20.0% vs 3.3%, P = 0.001). Of the 25 malignant lesions detected, all but one was detected in exams judged appropriate or uncertain.

CONCLUSION: This study shows a good adherence to ASGE guidelines by the referring physicians and a significant increase of the diagnostic yield in appropriate examinations, namely in detecting neoplastic lesions. It underscores the importance that the appropriateness of the indication assumes in assuring high-quality GI endoscopic procedures.

Acute necrotizing esophagitis: a large retrospective case series

BACKGROUND AND STUDY AIMS

Acute necrotizing esophagitis is a rarely described entity. Its incidence has not yet been established, and its multifactorial etiology remains unknown. The aim of the present study was to establish the incidence, clinical presentation, endoscopic course, accompanying factors, and pathogenesis of the condition.

PATIENTS AND METHODS

A retrospective analysis of clinical, laboratory, endoscopic and histological data and the clinical course in 29 patients with acute necrotizing esophagitis was carried out over a 5-year period.

RESULTS

Acute necrotizing esophagitis was observed in 29 of 10 295 upper gastrointestinal endoscopies (0.28 %) carried out during the 5-year period. The average age of the patients was 75.24 years (range 40 - 91), and they were predominantly male. Eighty-three percent of the patients had comorbid conditions. In all cases, acute necrotizing esophagitis became evident with upper gastrointestinal bleeding, without hemodynamic stabilization in the majority of cases (75.9 %). The lesions predominantly affected the lower two-thirds of the esophagus (59 %), and there were coexisting abnormal endoscopic findings in 83 % of cases. Empirical supportive therapy, including oral nutritional rest, omeprazole, sucralfate (15 cases) and broad-spectrum antibiotics (7 cases) was provided. The condition resolved in all patients. Ten patients in the group died of other causes (coexisting illnesses).

CONCLUSIONS

Acute necrotizing esophagitis was more commonly recognized than has previously been reported. It is a serious clinical entity that should be considered in the differential diagnosis of upper gastrointestinal bleeding, particularly in elderly patients. The prognosis depends more on the patient's advanced age and on comorbid illnesses than on the course of the esophageal lesions, which resolved in all patients in this series.

Effect of wide spectrum anti-helminthic drugs upon Schistosoma mansoni experimentally infected mice

Mebendazole, albendazole, levamisole and thiabendazole are well known as active drugs against several nematode species, and against cestodes as well, when the first two drugs are considered. None of the drugs have proven activity, however, against trematodes. We tested the effect of these drugs on the fecal shedding of schistosome eggs and the recovering of adult schistosomes, after portal perfusion in Schistosoma mansoni experimentally infected mice. Balb/c mice infected with 80 S. mansoni cercariae were divided into three groups, each in turn subdivided into four other groups, for each tested drug. The first group was treated with each one of the studied drugs 25 days after S. mansoni infection; the second group was submitted to treatment with each one of the drugs 60 days after infection. Finally, the third group, considered as control, received no treatment. No effect upon fecal shedding of S. mansoni eggs and recovering of schistosomes after portal perfusion was observed when mice were treated with either mebendazole or albendazole. Mice treated with either levamisole or thiabendazole, on the other hand, showed a significant reduction in the recovering of adult schistosomes after portal perfusion, mainly when both drugs were given during the schistosomula evolution period, i.e., 25 days after cercariae penetration, probably due to unspecific immunomodulation.

Expression of functional Raphanus sativus antifungal protein in yeast

Rs-AFP2 is a 51 amino acid cysteine-rich peptide isolated from radish (Raphanus sativus) seeds that exhibits potent inhibitory activity against filamentous fungi. A cDNA clone encoding the Rs-AFP2 preprotein was modified by recombinant DNA methods to allow expression in the yeast Saccharomyces cerevisiae. This peptide was expressed in yeast as a fusion protein carrying at its N-terminus the prepro-sequences derived from the precursor of the yeast pheromone mating factor alpha 1. These sequences allow secretion of the biologically active peptide in a correctly processed form. Deletion of the mating factor alpha 1 pro-peptide drastically reduced the expression level of the peptide.