Collagen Quality Research Articles

Microbiological aspects of dental health in children with osteogenesis imperfecta

Background. Oral microbiome actively affects the child’s health and is an available tool for diagnosing and predic­ting dental and systemic diseases. Studying the colonization of the oral cavity by cariogenic and periodontopathogenic bacteria, given the congenital, genetically determined decrease in the quality of collagen in children with osteogenesis imperfecta, is an urgent problem. The purpose of the study was to determine the level of cariogenic and periodontopathogenic microorganisms in the oral cavity of children with osteogenesis imperfecta. Materials and methods. Clinical studies were conducted with the participation of children aged 2 to 17 years diagnosed with osteogenesis imperfecta, in whom the level of contamination of the oral cavity with cariogenic bacteria Streptococcus mutans and Lactobacter spp. and periodontal pathogens Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Treponema denticola, Bacteroides forsythus, Prevotella intermedia was determined. Results. All children with osteogenesis imperfecta were found to have a borderline high level of Streptococcus mutans contamination and the presence of periodontal pathogens of the first order, mainly in the form of monocultures in preclinical concentration, which, against the background of low collagen quality, indicates a sufficiently high risk of developing ­caries and periodontal diseases.

An improved linear systems model of hydrothermal isometric tension testing to aid in assessing bone collagen quality: Effects of ribation and type-2 diabetes.

This study sought to further develop and validate a previously proposed physics-based model that maps denaturation kinetics from differential scanning calorimetry (DSC) to the isometric tension generated during hydrothermal isometric tension (HIT) testing of collagenous tissues. The primary objectives of this study were to verify and validate two physics-based model parameters: α, which indicates the amount of instantaneous isometric tension developed per unit of collagen denaturation, and β, which captures the proportionality between temperature and the generated isometric tension post denaturation initiation. These parameters were used as measures of bone collagen quality, employing data from HIT and DSC testing of human bone collagen from two previous studies. Additionally, given the physical basis of the model, the study aimed to further validate Max.Slope, the rate of change in isometric tensile stress with change in temperature, as an independent measure of collagen network connectivity. Max.Slope has previously been positively correlated with measures of cortical bone fracture resistance. Towards this verification and validation, the hypotheses were a) that α would correlate strongly with HIT denaturation temperature, Td, and the enthalpy of melting (ΔH) from DSC, and b) that β would correlate positively and strongly with Max.Slope.The model was employed in the analysis of HIT-DSC data from the testing of demineralized bone collagen isolated from cadaveric human femurs in two prior studies. In one study, data were collected from HIT-DSC testing of cortical bone collagen from 74 donors. Among them, 38 had a history of type 2 diabetes +/− chronic kidney disease, while the remaining 36 had no history of T2D again with or without CKD. Cortical bone specimens were extracted from the lateral mid-shaft. The second study involved 15 donor femora, with four cortical bone specimens extracted from each. Of these four, two specimens underwent a 4-week incubation in 0.1 M ribose at 37 °C to induce non-enzymatic ribation and advanced glycation endproducts, while the other two served as non-ribated controls.The examination involved investigating correlations between the model parameters α and β and various measures, such as Max.Slope, Td, ΔH, age, and duration of type 2 diabetes. The results revealed positive correlations between the model parameter β and Max.Slope (r = 0.55–0.58). The parameter α was found to be associated with Td, but also sensitive to the shape of the HIT curve around Td resulting in difficulties with variability and interpretation. As a result, while both hypotheses are confirmed, Max.Slope and β are better indicators of bone collagen quality because they are measures of the connectivity or, more generally, the integrity of the bone collagen network.

ADVANCEMENTS IN OSTEOGENESIS IMPERFECTA TREATMENT: FROM GENETICS TO PERSONALIZED THERAPIES

Osteogenesis imperfecta (OI) is a complex genetic disorder characterized by fragile bones and frequent fractures. It is primarily caused by mutations affecting collagen type I production. Recent advancements in genetic research have identified multiple genes involved in the disorder, broadening the scope of potential targeted therapies. This narrative review synthesizes the latest developments in the management and treatment of OI, focusing on personalized therapeutic interventions.OI is classified into several types based on genetic mutations, each with distinct clinical manifestations. Most cases are linked to mutations in the COL1A1 and COL1A2 genes, which directly affect collagen quality and the bone matrix structure. Emerging therapies explored in this review include bisphosphonates, genetic engineering techniques such as CRISPR/Cas9, and novel pharmacological agents targeting specific molecular pathways involved in bone metabolism and repair. Recent studies have shown promising results in using gene therapy to correct defective genes and employing targeted drug therapies to modulate bone formation and resorption processes. These advancements underscore the potential of personalized medicine in providing more effective management strategies for patients with OI.The genetic heterogeneity of OI necessitates a multifaceted approach to treatment that encompasses both the correction of genetic defects and the modulation of bone metabolism pathways. Innovations in genetic engineering and drug therapy are paving the way for more tailored and effective treatments, which promise to significantly improve the quality of life for individuals with OI. Ongoing research and clinical trials are crucial for furthering our understanding of the disease mechanisms and developing safer, more effective therapeutic options.

EARLY RESULTS OF GLUTEAL CUFF RECONSTRUCTION AND AUGMENTATION

Gluteal Tendinopathy is a poorly understood condition that predominantly affects post-menopausal women. It causes lateral hip pain, worse when lying on the affected side or when walking up a hill or stairs. It has been labelled ˜Greater Trochanteric Pain Syndrome” a name that recognises the lack of understanding of the condition.Surgical reconstruction of the gluteal cuff is well established and has been undertaken numerous times over the last 16 years by the senior author (AJL). However, the quality of collagen in the tendons can be very poor and this leads to compromised results. We present the results of gluteal cuff reconstruction combined with augmentation using a bioinductive implant.14 patients (11 female, 3 male; mean age 74.2 ± 6.3 years) with significant symptoms secondary to gluteal tendinopathy that had failed conservative treatment (ultrasound guided injection and structured physiotherapy) underwent surgical reconstruction by the senior author using an open approach. In all cases the iliotibial band was lengthened and the trochanteric bursa excised. The gluteal cuff was reattached using Healicoil anchors (3–5×4.75mm anchors; single anchors but double row repair) and then augmented using a Regeneten patch. Patients were mobilised fully weight bearing post-operatively but were asked to use crutches until they were no longer limping. All had structured post-surgery rehabilitation courtesy of trained physiotherapists.There were no post-operative complications and all patients reported an improvement in pain levels (Visual Analogue Scale 7.8 pre-op; 2.6 post-op) and functional levels (UCLA Activity Score 3.5 pre-op; 7.1 post-op) at 6 months post surgery.Surgery for gluteal tendinopathy produces good outcomes and the use of Regeneten as an augment for poor quality collagen is seemingly a safe, helpful addition. Further comparative studies would help clarify this.

Hydrolyzed Collagen Quality Control by Dynamic Light Scattering

Hydrolyzed Collagen Quality Control by Dynamic Light Scattering

Tunable polymer-peptide hybrids for dentin tissue repair

ObjectivesThis study targets to assess the remineralization capability of conditioned dentin infiltrated with polymeric nanoparticles (NPs) doped with tideglusib (TDg) (TDg-NPs). MethodsDentin conditioned surfaces were infiltrated with NPs and TDg-NPs. Bonded interfaces were created, stored for 24 h and submitted to mechanical and thermal challenging. Resin-dentin interfaces were evaluated through nanohardness, Masson's trichrome staining microscopy, and Raman analysis. ResultsDentin surfaces treated with TDg-NPs and load cycled produced higher nanohardness than the rest of the groups at the hybrid layer. At the bottom of the hybrid layer, all samples treated with TDg-NPs showed higher nanohardness than the rest of the groups. Active remineralization underneath the hybrid layer was detected in all groups after TDg application and load cycling, inducting new dentinal tubuli formation. After thermocycling, remineralization at the hybrid layer was not evidenced in the absence of NPs. Raman analysis showed increase mineralization, enriched carbonate apatite formation, and improved crosslinking and scaffolding of the collagen. ConclusionsMechanical loading on the specimens obtained after TDg-NPs dentin infiltration inducts an increase of mineralization at the resin/dentin interface, indicating remineralization of peritubular and intertubular dentin with augmented crystallographic maturity in crystals. Enriched collagen quality was produced, generating an adequate matrix organization to promote apatite nucleation, after tideglusib infiltration. Clinical significanceAt the present research, it has been proved the creation of reparative dentin, at the resin-dentin interface, after tideglusib dentin infiltration. Chemical stability, to favor integrity of the resin-dentin interface, is warranted in the presence of the TDg-NPs in the demineralized dentin collagen.

Effect of tremella polysaccharides on the quality of collagen jelly: insight into the improvement of the gel properties and the antioxidant activity of yak skin gelatin.

The present study aimed to investigate the effects of tremella polysaccharides on the gel properties and antioxidant activity of yak skin gelatin with a view to improving the quality of collagen jellies. The preparation of composite gels were performed by yak skin gelatin (66.7 mg mL-1) and tremella polysaccharides with different concentrations (0, 2, 4, 6, 8 mg mL-1), and finally the collagen jelly was prepared by composite gel (yak skin gelatin: 66.7 mg mL-1; tremella polysaccharides:6 mg mL-1) with the best performance. Tremella polysaccharides not only improved the hardness, springiness, gel strength, water holding capacity and melting temperature of yak skin gelatin, but also enhanced the composite gel's scavenging activity against ABTS radicals, DPPH radicals, O2 and OH radicals. The filling of tremella polysaccharides into the gelatin network increased the number of crosslinking sites inside the gel, which resulted in the gel network structure becoming dense and orderly. The gel particles became finer and more uniform, and the thermal stability was improved. Furthermore, the sensory score of commercially available gelatin jelly decreased more rapidly during storage compared to the composite gel jelly. The gel properties and antioxidant activity of yak skin gelatin were improved by adding tremella polysaccharides, and then the quality and storage properties of the jelly were improved, which also provided technical reference for the development of functional gel food. © 2024 Society of Chemical Industry.

Polysacharide of Agaricusblazei gel mitigates bone necrosis in model of the jaws related to bisphosphonate via Wnt signaling

To investigate de effect of PAb gel on the bone tissue of rats submitted to Bisphosphonate-related osteonecrosis of the jaws (BRONJ). Initially, 54 animals were submitted to BRONJ model by Zoledronic Acid (ZA) (0.1 mg/kg 3x/wk for 9 wk, ip), followed by the 1st upper left molar extraction at the 8th wk. After tooth removal, the animals were divided into 3 groups, ZA that received placebo gel or PAb gel that received 1% PAb gel, inside the dental alveolus. The control Group (CONTROL) received 0.1 mg/kg of 0.9% saline and then placebo gel. Three weeks after tooth extraction, the animals were euthanized, and maxillae were colleted for macroscopic, radiographic, histological and Raman spectomery assays. Additionally, GSK3b, beta-catenin, and Runx2 mRNA expressions were determined. Blood samples were collected for the analysis of Bone-specific alkaline phosphatase (BALP) levels. PAb gel improved mucosal healing, increased the number of viable osteocytes, while it reduced the number of empty lacunae, as well as the amount of bone sequestration. Furthermore, PAb gel positively influenced the number and functionality of osteoblasts by stimulating Wnt signaling, thereby inducing bone remodeling. Additionally, PAb gel contributed to improved bone quality, as evidenced by an increase in bone mineral content, a decrease in bone solubility, and an enhancement in the quality of collagen, particularly type I collagen. PAb gel mitigated bone necrosis by stimulating of bone remodeling through Wnt signaling and concurrently improved bone quality. PAb gel emerges as a promising pharmacological tool for aiding in BRONJ therapy or potentially preventing the development of BRONJ.

Abstract 5571: Collagen stabilization directs immune suppression in the head and neck squamous cell carcinoma hypoxic subtype

Abstract Head & neck squamous cell carcinoma (HNSCC) show limited clinical benefit to immune checkpoint inhibitors (ICI). Interactions between extracellular matrix (ECM), tumor, and immune cells underly the mechanisms leading to immunosuppression and resistance to ICIs. Collagen matrix remodeling within tumor stroma can influence accessibility and function of immune cells. Specifically, telopeptidyl lysine residues in fibrillar collagen can be hydroxylated by Lysyl hydroxylase 2 (LH2) prior to cross-linking which leads to stiffened, stable collagen. We previously showed that this LH2-modified tumor microenvironment (TME) drives HNSCC invasion and metastasis. Here, we elucidate the interplay between LH2-modified collagen and the immune landscape within TME of hypoxic and immunosuppressive HNSCC. Bioinformatics analyses of RNAseq datasets were performed to assess pathways regulating collagen deposition and stabilization. Tissue microarray having 81 primary, 28 recurrent primary, and 3 lymph node metastases tumor cores was analyzed. Cores were classified according to our published Hypoxia-Immune signature (Chaudhary R. et al. 2023, Can Res Comm). We performed Second Harmonic Generation imaging of H&E stained TMA section to analyze the orientation and length of collagen fibrils. Picrosirius red (PSR) staining allowed quantification of total collagen and collagen maturation was assessed by polarized light imaging of birefringence. Further, we performed multiplex immunofluorescence staining for CD3+ (T-cell); CD14+ (Monocyte & Macrophage); CD11c+ (Dendritic); Pax5+ (B-cell); Pan-Cytokeratin+ (tumor), and LH2. Low (0-1) LH2 expression was seen in 29.5% of analyzed cores whereas 70.5% of cores scored high (2-3) for LH2 expression. Cores classified under the hypoxia subtype exhibit high LH2 and enrichment of collagen stability signature. Late-stage tumors have highly oriented collagen fibers compared to normal tissue or early-stage tumors which have randomly distributed fibers. CT-Fire-based measurements revealed that LH2hi cores have significantly increased fiber length and lower coefficient of variance for fiber angles. The area of collagen measured by PSR staining had no correlation with tumor stage or subtype indicating that collagen deposition is similarly high in HNSCCs. However, birefringence measurements showed that a higher fraction of mature fibrillar collagen is associated with late-stage LH2hi tumors. Interestingly, LH2 expression positively correlated with increased CD3+ T cells in stroma suggesting that anti-tumor T cells are physically obstructed by the presence of LH2-stabilized and stiffened collagen fibers. LH2 expression influences the quality of collagen but not the quantity. Understanding the effect of LH2-mediated collagen modifications on the TIME may have implications for therapeutic strategies to enhance anti-tumor immune response in HNSCC. Citation Format: Sonal Srivastava, John Powers, Ritu Chaudhary, Sadegh Marzban, Robbert J. Slebos, Jeffrey West, Xiaofei Song, Jose A. Guevara-Patino, Christine H. Chung, Antonio L. Amelio. Collagen stabilization directs immune suppression in the head and neck squamous cell carcinoma hypoxic subtype [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5571.

Platelets modulate cardiac remodeling via the collagen receptor GPVI after acute myocardial infarction.

Platelets play an important role in cardiovascular diseases. After acute myocardial infarction, platelets display enhanced activation and migrate into the infarct zone. Furthermore, platelets trigger acute inflammation and cardiac remodeling leading to alterations in scar formation and cardiac function as observed in thrombocytopenic mice. GPVI is the major collagen receptor in platelets and important for platelet activation and thrombus formation and stability. Antibody induced deletion of GPVI at the platelet surface or treatment of mice with recombinant GPVI-Fc results in reduced inflammation and decreased infarct size in a mouse model of AMI. However, the role of GPVI has not been fully clarified to date. In this study, we found that GPVI is not involved in the inflammatory response in experimental AMI using GPVI deficient mice that were analyzed in a closed-chest model. However, reduced platelet activation in response to GPVI and PAR4 receptor stimulation resulted in reduced pro-coagulant activity leading to improved cardiac remodeling. In detail, GPVI deficiency in mice led to reduced TGF-β plasma levels and decreased expression of genes involved in cardiac remodeling such as Col1a1, Col3a1, periostin and Cthrc1 7 days post AMI. Consequently, collagen quality of the scar shifted to more tight and less fine collagen leading to improved scar formation and cardiac function in GPVI deficient mice at 21d post AMI. Taken together, this study identifies GPVI as a major regulator of platelet-induced cardiac remodeling and supports the potential relevance of GPVI as therapeutic target to reduce ischemia reperfusion injury and to improve cardiac healing.

Chemical characterization and effects of volatile oil of Alpinia zerumbet on the quality of collagen deposition and caveolin-1 expression in a muscular fibrosis murine model.

This study evaluated the effect of the volatile oil of Alpinia zerumbet (VOAz) on caveolin-1 gene expression and muscular fibrosis. The rats were immobilized to induce fibrosis of the gastrocnemius muscle, and they were treated with VOAz. Collagen quality was assessed by histology and the expression of the caveolin-1 (CAV-1) gene was evaluated using qPCR. Histomorphological analysis indicated a significant reduction in the perimeter, width, and intensity of collagen in the treated groups, thus showing that the oil was effective in regulating the quality of collagen at the three concentrations. The results of expression levels suggested a decrease in the lesioned group and in two treatment groups (0.0115 µg/g and 0.009 µg/g). However, with the lowest concentration (0.0065 µg/g), no significant difference was observed, with levels similar to those found in healthy tissue. Therefore, the results showed that VOAz has the potential to be a non-invasive and low-cost alternative to aid in the treatment of muscular fibrosis.

In Vivo Assessment of Skin Surface Pattern: Exploring Its Potential as an Indicator of Bone Biomechanical Properties.

The mechanical properties of bone tissue are the result of a complex process involving collagen-crystal interactions. The mineral density of the bone tissue is correlated with bone strength, whereas the characteristics of collagen are often associated with the ductility and toughness of the bone. From a clinical perspective, bone mineral density alone does not satisfactorily explain skeletal fragility. However, reliable in vivo markers of collagen quality that can be easily used in clinical practice are not available. Hence, the objective of the present study is to examine the relationship between skin surface morphology and changes in the mechanical properties of the bone. An experimental study was conducted on healthy children (n = 11), children with osteogenesis imperfecta (n = 13), and women over 60 years of age (n = 22). For each patient, the skin characteristic length (SCL) of the forearm skin surface was measured. The SCL quantifies the geometric patterns formed by wrinkles on the skin's surface, both in terms of size and elongation. The greater the SCL, the more deficient was the organic collagen matrix. In addition, the bone volume fraction and mechanical properties of the explanted femoral head were determined for the elderly female group. The mean SCL values of the healthy children group were significantly lower than those of the elderly women and osteogenesis imperfecta groups. For the aged women group, no significant differences were indicated in the elastic mechanical parameters, whereas bone toughness and ductility decreased significantly as the SCL increased. In conclusion, in bone collagen pathology or bone aging, the SCL is significantly impaired. This in vivo skin surface parameter can be a non-invasive tool to improve the estimation of bone matrix quality and to identify subjects at high risk of bone fracture.

Tumor associated macrophages in relation to collagen quality and their role in aggressiveness of giant cell granulomas of the jaws

Tumor associated macrophages in relation to collagen quality and their role in aggressiveness of giant cell granulomas of the jaws

Comparison of DNA preservation and ATR-FTIR spectroscopy indices of cortical and trabecular bone of metacarpals and metatarsals

Shape, size, composition, and function of the bones in the human body vary on the macro, micro and nanoscale. This can influence changes caused by taphonomy and post-mortem preservation, including DNA. Highly mineralised compact bone is less susceptible to taphonomic factors than porous trabecular bone. Some studies imply that DNA can be better preserved in trabecular bone, due to remnants of the soft tissue or bacteria better digesting organic matter while not digesting DNA. The aim of this study was to understand the differences between compact (diaphyses) and trabecular (epiphyses) bone on a molecular level and thus the reasons for the better preservation of the DNA in the trabecular bone. The powder obtained from epiphyses and diaphyses of metacarpals and metatarsals was analysed using ATR-FTIR spectroscopy and compared. Samples with poorest DNA preservation originated from diaphyses, predominantly of metatarsals. They were characterised by higher concentrations of phosphates and crystallinity, while lower collagen quality in comparison to samples with the best DNA preservation. Epiphyses presented higher concentrations of better-preserved collagen while diaphyses had higher concentrations of carbonates and phosphates and higher crystallinity. Due to better-preserved collagen in the epiphyses, the soft tissue remnants hypothesis seems more likely than the bacteria hypothesis.

Collagen-Based Hydrogels for the Eye: A Comprehensive Review.

Collagen-based hydrogels have emerged as a highly promising platform for diverse applications in ophthalmology, spanning from drug delivery systems to biomedical interventions. This review explores the diverse sources of collagen, which give rise to different types of collagen protein. The critical isolation and purification steps are discussed, emphasizing their pivotal role in preparing collagen for biomedical use. To ensure collagen quality and purity, and the suitability of collagen for targeted applications, a comprehensive characterization and quality control are essential, encompassing assessments of its physical, chemical, and biological properties. Also, various cross-linking collagen methods have been examined for providing insight into this crucial process. This comprehensive review delves into every facet of collagen and explores the wide-ranging applications of collagen-based hydrogels, with a particular emphasis on their use in drug delivery systems and their potential in diverse biomedical interventions. By consolidating current knowledge and advancements in the field, this review aims to provide a detailed overview of the utilization of engineered collagen-based hydrogels in ocular therapeutics.

Optimization of the technique for manufacturing the osteoplastic material based on type 1 human collagen and allogeneic bone chips

Introduction. Biological grafts, including bone chips and collagen, are supposed to be promising in the treatment of bone tissue treatment. Nevertheless, manufacturing of these grafts still needs to be standardized. Aim. To optimize methodology of osteoplastic material production, based on allogenic 1 type collagen and bone chips. Material and methods. Osteoplastic material grafts were produced, using with allogeneic bone chips 180-800 µm and type 1 collagen solution in acidic acid. We studied total integrity of graft, collagen quality, morphofunctional properties of line M-22 human cells interacting with different type of osteoplastic material grafts. Results. Procedures for manufacturing the osteoplastic material did not significantly affect the quality of collagen in its composition, while lyophilized grafts had pronounced acidogenic and toxic effects in cell culture. Soaking osteoplastic material in isotonic solution for 30 min or longer increased its biocompatibility in vitro. Adhesion properties of osteoplastic material widely varied depending on collagen concentration and bone chips size. Conclusion. Osteoplastic material prepared with allogeneic bone chips of 180–800 µm and collagen solution in acidic acid had pronounced acidogenic and toxic effects in vitro that could be considerably reduced by soaking in isotonic solution. Varying the collagen concentration and the size of bone chips one could produce biocompatible osteoplastic material grafts with high and low adhesion properties.

Effect of Ultrasonic Amplitude on the Yield and Properties of Barramundi (Lates calcarifer) Skin Collagen

Barramundi skin, a by-product of the fish processing industry, has shown potential as an alternative collagen source. However, the commonly used acid extraction method to produce collagen rendered a low yield requires a lengthy time and is not environmentally friendly. As a result, the adoption of greener technology, such as ultrasound, to improve the conventional extraction process is emerging. This study aimed to investigate the effect of different ultrasonication amplitudes on collagen recovery from barramundi skin. The resulting collagens were evaluated for their protein, hydroxyproline and moisture content, colour, molecular weight distribution, and FTIR spectra. Ultrasound-assisted extraction (UAE) was performed at 40 (UAE40), 60 (UAE60) and 80 (UAE80) % amplitude for 20 min. For comparison, acetic acid extraction was also carried out to produce acid-soluble collagen (ASC). UAE increased the yield (p<0.05) of collagen from barramundi skin, with UAE80 exhibiting a 7-fold increment compared to ASC. Increasing the ultrasonic amplitude increased the yield considerably but decreased the hydroxyproline content, indicating a reduction in collagen quality. Furthermore, the protein content and SDS-PAGE profile of the extracted collagens revealed that UAE promoted protein degradation. FTIR spectra indicated that despite slightly varying wavenumbers, no detrimental effect on the triple helical structure was seen following UAE with the presence of amides A, B, I, II, and III. Also, the α1, α2 and ß-chains were found in all samples, although the band intensity reduced as the amplitude increased. In conclusion, given the right conditions, UAE could improve the extraction yield without influencing the collagen structure.

Role of endoplasmic reticulum autophagy in acute lung injury.

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), the prime causes of morbidity and mortality in critically ill patients, are usually treated by general supportive treatments. Endoplasmic reticulum autophagy (ER-phagy) maintains cellular homeostasis by degrading damaged endoplasmic reticulum (ER) fragments and misfolded proteins. ER-phagy is crucial for maintaining ER homeostasis and improving the internal environment. ER-phagy has a particular role in some aspects, such as immunity, inflammation, cell death, pathogen infection, and collagen quality. In this review, we summarized the definition, epidemiology, and pathophysiology of ALI/ARDS and described the regulatory mechanisms and functions of ER-phagy as well as discussed the potential role of ER-phagy in ALI/ARDS from the perspectives of immunity, inflammation, apoptosis, pathogen infection, and fibrosis to provide a novel and effective target for improving the prognosis of ALI/ARDS.

Abstract 2210: Importance of fibrillar collagen quality, not quantity, for patients with solid tumors

Abstract Background: Abnormal architectures of collagen fibers in the extracellular matrix (ECM) is directly related to cancer associated fibroblast (CAF) activity and subtype and are hallmarks of tumor fibrosis and key for determining prognosis and response to treatment in patients with solid tumors. Quantifiable tumor fibrosis biomarkers are needed for patient stratification and a non-invasive approach (liquid biopsy) is preferred in particular in the advanced setting. Type I collagen (COL1) and type V collagen (COL5) are two collagens responsible for the densely packed fibrils in the fibrotic tumor microenvironment. While COL1 is the most abundant collagen, COL5 is known for controlling collagen fibril size and orientation, and therefore fibrillar collagen quality. Increased fibrotic activity results in release of collagen pro-peptides into the bloodstream of patients with cancer. In this study, we first evaluated the clinical utility of non-invasive collagen based liquid biomarkers of COL1 and COL5 in patients with various solid tumors and subsequently evaluated prognostic utility in patients with pancreatic cancer (PC). Methods: In a discovery cohort, pro-peptides of COL1 (PRO-C1) and COL5 (PRO-C5) were measured in serum from patients with various stages of bladder-, breast-, colorectal-, head and neck-, kidney-, lung-, melanoma-, pancreatic-, prostate-, and stomach cancer (n=220) and compared to healthy controls (n=33). Based on these results, the biomarker potential of PRO-C5 was validated further in 814 patients with PC from the BIOPAC cohort (n=15, 201, 164 and 434 for stage 1-4, respectively) including assessment for associations with overall survival (OS) analyzed by Kaplan-Meyer curves and Cox regression analysis, alone, and after adjusting for age, gender, BMI, diabetes, smoking, CA19-9, stage, no. of metastatic sites, performance status, and cachexia. Results: PRO-C5, not PRO-C1, was significantly elevated in serum from all types of cancer patients compared to healthy controls (p<0.05 - p<0.0001). Levels of PRO-C5 were similar in patients from the BIOPAC cohort to those found in the discovery cohort. Furthermore, when dividing patients from the BIOPAC cohort into quartiles based on PRO-C5 levels (Q1-Q4) a stepwise decrease was detected in median OS time (log rank, p<0.0001). Moreover, patients in the upper quartile of PRO-C5 (Q4) had 65% increased risk of dying compared to patients in Q1 (HR=1.65, 1.35-2.02, p<0.0001) and this remained significant after adjusting for other common risk factors by multivariate analysis (HR=1.69, 1.30-2.20, p=0.0001). Conclusion: Type V collagen (COL5) pro-peptides measured in serum (PRO-C5) is a promising pan-tumor fibrosis liquid biopsy with indications of independent prognostic value in patients with pancreatic cancer. In the future, this may provide means for serological subtyping of CAF subtypes which will aid in treating cancer patients. Citation Format: Neel Ingemann Nissen, Astrid Z. Johansen, Inna M. Chen, Christina Jensen, Carsten Palnæs Hansen, Jeppe Thorlacius-Ussing, Morten Karsdal, Julia S. Johansen, Nicholas Willumsen. Importance of fibrillar collagen quality, not quantity, for patients with solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2210.

Comparing the performance of demineralization agents (HCl and EDTA) for stable isotope analysis of bone collagen with implications for quality control criteria and collagen yield

AbstractStable isotope analysis of ancient bone collagen is a powerful technique for studying diet, migration, and ecology in archeological contexts. These analyses are, however, limited by collagen preservation and prohibitively low collagen yields. Harsh chemical demineralization is required to isolate the collagen from the mineral component of the bone, which in turn reduces the yield of material available for analysis. Demineralization is typically performed using hydrochloric acid (HCl), which reduces collagen yield via acid hydrolysis of peptide bonds. An alternative to a strong acid (HCl) treatment is the neutral chelating agent ethylenediaminetetraacetic acid (EDTA). To our knowledge, it has never been empirically tested whether EDTA treatment reduces collagen loss relative to HCl in samples that are known to be poorly preserved (i.e., low yields and/or collagen extracts failing other collagen quality control [QC] criteria). We tested the effect of the demineralization agent on collagen yield, stable isotope, and elemental composition of poorly preserved ancient bone samples. Collagen yield was significantly higher in EDTA‐treated samples; however, this did not translate into a greater number of samples passing relevant quality control criteria. Stable isotope compositions (SIC) were also not significantly different between treatments. The atomic C:N ratio of samples treated with EDTA was significantly lower than equivalent samples treated with HCl, which is likely a product of increased deamidation of asparagine and glutamine residues when collagen is demineralized with HCl relative to EDTA. We conclude that although EDTA treatment may reduce collagen loss relative to HCl treatment, this does not necessarily increase the probability of producing reliable–stable isotope data from bone samples yielding low amounts of collagen. Based on our isotopic data, we suggest the following provisional collagen QC criteria for EDTA‐demineralized samples: collagen yield > 2%, wt% C > 4%, wt% N > 2%, and atomic C:N ratio between 2.80 and 3.25.