Lower Collagen Content Research Articles

Distribution and Maturity of Medial Collagen Fibers in Thoracoabdominal Post-Dissection Aortic Aneurysms: A Comparative Study of Marfan and Non-Marfan Patients.

Thoracoabdominal aortic aneurysms (TAAAs) are rare but serious conditions characterized by dilation of the aorta characterized by remodeling of the vessel wall, with changes in the elastin and collagen content. Individuals with Marfan syndrome have a genetic predisposition for elastic fiber fragmentation and elastin degradation and are prone to early aneurysm formation and progression. Our objective was to analyze the medial collagen characteristics through histological, polarized light microscopy, and electron microscopy methods across the thoracic and abdominal aorta in twenty-five patients undergoing open surgical repair, including nine with Marfan syndrome. While age at surgery differed significantly between the groups, maximum aortic diameter and aneurysm extent did not. Collagen content increased from thoracic to infrarenal segments in both cohorts, with non-Marfan patients exhibiting higher collagen percentages, notably in the infrarenal aorta (729.3 nm vs. 1068.3 nm, p = 0.02). Both groups predominantly displayed mature collagen fibers, with the suprarenal segment containing the highest proportion of less mature fibers. Electron microscopy revealed comparable collagen fibril diameters across segments irrespective of Marfan status. Our findings underscore non-uniform histological patterns in TAAAs and suggest that ECM remodeling involves mature collagen deposition, albeit with lower collagen content observed in the infrarenal aorta of Marfan patients.

Prognostic significance of collagen content in solitary fibrous tumors of the central nervous system.

We aimed to explore the prognostic significance of collagen content in solitary fibrous tumors (SFTs) of the central nervous system (CNS) and preliminarily investigate its relationship with magnetic resonance imaging (MRI) features of SFTs. Collagen content was identified using Masson's trichrome staining, and quantitatively assessed. Radiomic methods were applied to extract quantitative MRI features of SFTs, which were then analyzed in relation to collagen content. The collagen content in CNS SFTs was categorized into high- and low-content groups, with a cutoff value of 6%. Survival analysis indicated a positive correlation between collagen content and overall survival (OS). In multivariate Cox regression analysis, incorporating factors such as mitosis, necrosis, Ki67, and collagen content and other indicators, collagen content emerged as an independent prognostic factor. Collagen content demonstrated a negative correlation with tumor histological phenotype, Ki67, WHO grade, mitosis, necrosis, and brain invasion. Additionally, the signal intensity of SFTs on T2-weighted imaging (T2WI) decreased with increasing collagen content. Radiomics analysis identified 1,702 features from each patient's region of interest, with 12 features showing significant differences between the high and low collagen content groups. Among the quantitative parameters and radiomic models, the combined T1- and T2WI models exhibited the highest diagnostic performance. These findings suggest that collagen content is an independent prognostic risk factor for OS. Furthermore, combined radiomic models based on T1-and T2WI sequences may offer a more comprehensive, objective, and accurate assessment of collagen content in CNS SFTs.

Loss of collagen content is localized near cartilage lesions on the day of injurious loading and intensified on day 12.

Joint injury can lead to articular cartilage damage, excessive inflammation, and post-traumatic osteoarthritis (PTOA). Collagen is an essential component for cartilage function, yet current literature has limited understanding of how biochemical and biomechanical factors contribute to collagen loss in injured cartilage. Our aim was to investigate spatially dependent changes in collagen content and collagen integrity of injured cartilage, with an explant model of early-stage PTOA. We subjected calf knee cartilage explants to combinations of injurious loading (INJ), interleukin-1α-challenge (IL) and physiological cyclic loading (CL). Using Fourier transform infrared microspectroscopy, collagen content (Amide I band) and collagen integrity (Amide II/1338 cm-1 ratio) were estimated on days 0 and 12 post-injury. We found that INJ led to lower collagen content near lesions compared to intact regions on day 0 (p < 0.001). On day 12, near-lesion collagen content was lower compared to day 0 (p < 0.05). Additionally, on day 12, INJ, IL, and INJ + IL groups exhibited lower collagen content along most of tissue depth compared to free-swelling control group (p < 0.05). CL groups showed higher collagen content along most of tissue depth compared to corresponding groups without CL (p < 0.05). Immunohistochemical analysis revealed higher MMP-1 and MMP-3 staining intensities localized within cell lacunae in INJ group compared to CTRL group on day 0. Our results suggest that INJ causes rapid loss of collagen content near lesions, which is intensified on day 12. Additionally, CL could mitigate the loss of collagen content at intact regions after 12 days.

Pathological characteristics analysis of children with intermittent and persistent hydronephrosis due to uretero-pelvic junction obstruction.

To analyze from a pathological perspective the differences between intermittent and persistent hydronephrosis in children with uretero-pelvic junction obstruction. 23 children who underwent unilateral dismembered pyeloplasty (Anderson-Hynes operation) for intermittent hydronephrosis from September 2017 to March 2024 were included in the observation group. They were compared with a control group consisting of 23 children with persistent hydronephrosis matched for age, gender, and affected side. All children had the narrowed segment surgically excised during the operation, while other obstructive causes (such as polyps, crossing vessels, or tumor compression) were excluded. The specimens were analyzed for muscle and collagen content using Masson's trichrome staining, and the collagen-to-muscle ratio (CMR) was calculated. The number of Cajal-like cells was quantified with c-kit immunohistochemical staining. For all slides, 10 random fields of view were selected under a 400× optical microscope to record pathological data and calculate mean values. Pathological indicators between the two groups were compared using the T-test and the Chi-square test, with P < 0.05 considered statistically significant. The observation group showed a significant difference in the number of fields with low, medium, and high densities of Cajal-like cells compared to the control group [132 (57.4%) vs. 173 (75.2%); 70 (30.4%) vs. 38 (16.5%); 28(12.2%) vs. 19 (8.3%), P < 0.001]. The uretero-pelvic junction in children with intermittent hydronephrosis had lower collagen content, higher muscle content, and a more regular arrangement. The collagen-muscle ratio was significantly lower than that in children with persistent hydronephrosis [(1.59 ± 0.65) vs. (3.98 ± 1.19), P < 0.001]. Compared with persistent hydronephrosis, the narrowed segment at the uretero-pelvic junction in children with intermittent hydronephrosis has a higher density of Cajal-like cells; lower collagen content, and higher muscle content (lower collagen-muscle ratio).

Biomechanical and biochemical changes in murine skin during development and aging

Aging leads to biochemical and biomechanical changes in skin, with biological and functional consequences. Despite extensive literature on skin aging, there is a lack of studies which investigate the maturation of the tissue and connect the microscopic changes in the skin to its macroscopic biomechanical behavior as it evolves over time. The present work addresses this knowledge gap using multiscale characterization of skin in a murine model considering newborn, adult and aged mice. Monotonic uniaxial loading, tension relaxation with change of bath, and loading to failure tests were performed on murine skin samples from different age groups, complemented by inflation experiments and atomic force microscopy indentation measurements. In parallel, skin samples were characterized using histological and biochemical techniques to assess tissue morphology, collagen organization, as well as collagen content and cross-linking. We show that 1-week-old skin differs across nearly all measured parameters from adult skin, showing reduced strain stiffening and tensile strength, a thinner dermis, lower collagen content and altered crosslinking patterns. Surprisingly, adult and aged skin were similar across most biomechanical parameters in the physiologic loading range, while aged skin had lower tensile strength and lower stiffening behavior at large force values. This correlates with altered collagen content and cross-links. Based on a computational model, differences in mechanocoupled stimuli in the skin of the different age groups were calculated, pointing to a potential biological significance of the age-induced biomechanical changes in regulating the local biophysical environment of dermal cells. Statement of significanceSkin microstructure and the emerging mechanical properties change with age, leading to biological, functional and health-related consequences. Despite extensive literature on skin aging, only very limited quantitative data are available on microstructural changes and the corresponding macroscopic biomechanical behavior as they evolve over time. This work provides a wide-range multiscale mechanical characterization of skin of newborn, adult and aged mice, and quantifies microstructural correlations in tissue morphology, collagen content, organization and cross-linking. Remarkably, aged skin retained normal hydration and normal biomechanical function in the physiological loading range but showed significantly reduced properties at super-physiological loading. Our data show that age-related microstructural differences have a profound effect not only on tissue-level properties but also on the cell-level biophysical environment.

Acinar cells of the pancreas as an independent predictor of the development of postoperative pancreatic fistula: A review

Analysis of data published in the modern literature on the role of the number of functioning acinar cells of the pancreas as a prognostic marker of the development of pancreatic fistula. The search for sources was carried out in the systems Clinicaltrials.gov, PubMed, Medline, NCCN, Scopus, Elibrary. In writing the literature review, 52 sources published from 2004 to 2022 were used. Included are studies reflecting the importance of functioning acinar cells at the edge of pancreatic resection, as well as other factors associated with the development of pancreatic fistula and other post-resection complications. A large number of acinar cells (40%) and a low collagen content (15%) in the edge of pancreatic resection significantly correlates with the development of pancreatic fistula. The content of adipose tissue in the edge of pancreatic resection showed no connection with the development of pancreatic fistula and other complications after surgery. Palpatory assessment of the structure of the pancreatic parenchyma is subjective and can lead to erroneous interpretation and adoption of inadequate tactics of preventive measures. Intraoperative counting of acinuses at the edge of pancreatic resection is easy to use, while not yielding to more complex methods for assessing the risk of post-resection complications and can be recommended as a routine method for predicting the occurrence of pancreatic fistula

Alterations in the fillet quality of myostatin-knockout red sea bream Pagrus major: Preliminary insights into nutritional, compositional, and textural properties

Myostatin (MSTN) is a negative regulator of skeletal muscle growth and a popular target for enhancing the productivity of farmed fish. We previously developed an mstn-knockout breed of the aquaculture fish red sea bream (Pagrus major) using genome editing technology. However, little is known about the effects of mstn disruption on the fillet quality of red sea bream and other fish species. In this study, we used fillets of mstn-deficient red sea bream to evaluate their compositional and textural changes during refrigeration. Compared to the wild type, the mutant fillets exhibited an increase in moisture content and a decrease in drippings, indicating an enhanced water-holding capacity. Furthermore, the mutant fillets showed increased water retention and marginally lower collagen content, resulting in lower breaking force, an index of texture. In conclusion, we demonstrated that mstn disruption alters the compositional and textural properties of red sea bream fillets.

Macro-based collagen quantification and segmentation in picrosirius red-stained heart sections using light microscopy.

Picrosirius red staining constitutes an important and broadly used tool to visualize collagen and fibrosis in various tissues. Although multiple qualitative and quantitative analysis methods to evaluate fibrosis are available, many require specialized devices and software or lack objectivity and scalability. Here, we aimed to develop a versatile and powerful "QuantSeg" macro in the FIJI image processing software capable of automated, robust, and quick collagen quantification in cardiac tissue from light micrographs. To examine different patterns of fibrosis, an optional segmentation algorithm was implemented. To ensure the method's validity, we quantified the collagen content in a set of wild-type versus plakoglobin-knockout murine hearts exhibiting extensive fibrosis using both the macro and an established, fluorescence microscopy-based method, and compared results. To demonstrate the capabilities of the segmentation feature, rat hearts were examined post-myocardial infarction. We found the QuantSeg macro to robustly detect the differences in fibrosis between knockout and control hearts. In sections with low collagen content, the macro yielded more consistent results than using the fluorescence microscopy-based technique. With its wide range of output parameters, ease of use, cost effectiveness, and objectivity, the QuantSeg macro has the potential to become an established method for analysis of PSR-stained tissue. The novel segmentation feature allows for automated evaluation of different patterns of cardiac fibrosis for the first time.

Engineering and characterization of a hydrogel mimicking subcutaneous interstitial space

We have synthesized and characterized a collagen-hyaluronic acid hybrid network. The aim was to create a hydrogel mimicking the extracellular matrix of adipose tissue, primarily for use in in vitro studies of protein drug transport in the subcutaneous interstitial space. The network was created by covalently crosslinking methacryloyl-functionalized collagen type I and thiol-functionalized hyaluronic acid by means of thiol-Michael and thiol-ene photo-click reaction. The degree of modification corresponded to 74 % of the lysine and arginine groups on collagen, and 16 to 29 % of the carboxylate groups on hyaluronic acid, as determined with 1H NMR. Circular dichroism measurements showed that the triple helix of modified collagen remained intact. Oscillatory shear rheology tests showed that the hydrated networks displayed viscoelastic properties characteristic of hydrogels. The storage modulus, measured at 1 Hz frequency in the linear viscoelastic range (<5%), varied in a controllable way between 1.5 and 4 kPa depending on the collagen concentration and collagen-to-hyaluronic acid ratio. The hydrogels had a lower collagen content (0.6––1.2 wt%) but similar hyaluronic acid content and shear modulus at low strain rates as the extracellular matrix in adipose tissue and were penetrable by albumin and lysozyme. The results show that the hydrogels are promising as model systems for investigations of drug transport.

Histologic inflammation and collagen content are not positively correlated in human BPH.

Recent clinical studies have implicated prostate inflammation and fibrosis in the development of bladder outlet obstruction and lower urinary tract symptoms (LUTS). Studies utilizing rodent models, including work in our laboratory, have shown prostate fibrosis to occur as a consequence of inflammation. However, the relationship between collagen content and inflammation in human tissue samples obtained from surgical treatment of benign prostatic hypererplasia(BPH)/LUTS has not to our knowledge been previously examined. Prostate tissue specimens from 53 patients (ages 47-88, mean 65.1) treated by open simple prostatectomy or transurethral resection of the prostatefor BPH/LUTS were stained to quantitatively assess prostate inflammation and collagen content. Patients with prostate cancer present in greater than 5% of the surgical specimen were excluded. Prostate volume was determined from pelvic CT scan obtained within 2years of surgery. Analysis of the data showed that inflammation was inversely correlated with collagen content (r = -0.28, p = 0.04). In men with prostates less than 75 cm3 inflammation increases and collagen content decreases with prostate volume (p = 0.002 and p = 0.03, respectively) while in men with prostate volume over 75 cm3 inflammation decreases and collagen content increases with prostate volume (p = 0.30 and p = 0.005, respectively). Our data do not support the assumed positive association of prostate inflammation with collagen content. Coordinated analysis of scatter plots of inflammation and collagen content with prostate volume revealed a subset of prostates with volumes >50 cm3 prostate characterized by intense inflammation and low collagen content and it is this subgroup that appears most responsible for the inverse correlation of inflammation and collagen.

Identification and function of a C3 hiIL-33 +fibroblast population in the lungs

Abstract Complement component C3 is known to be predominantly expressed by epithelial and immune cells, however, we have found that fibroblasts are a primary source of C3 in murine and human lungs. Specifically, C3 is majorly expressed in adventitial fibroblasts. Moreover, we found that C3 hifibroblasts are characterized by the expression of IL-33. Further, C3 and IL-33 are not only markers of a novel subset of pulmonary adventitial fibroblasts but form a functional axis where C3 drives the expression of IL-33. As compared to other adventitial fibroblasts, this C3 hiIL-33 +subset is enriched for matrix genes, especially type I collagen (COL1A1). These cells require a functional C3− IL-33 axis to maintain their matrix identity. Impairing C3 not only reduces their ability to make collagen but guides them towards a lipofibroblast program characterized by lower collagen content and higher lipid accumulation. As we and others have published that C3 is a key driver of allergic airway inflammation, we wanted to understand how exposure to allergen affected C3 hiIL-33 +fibroblasts. Using a murine model of airway allergy, we observed a significant increase in the C3 hiIL33 +fibroblast population in lung samples from house dust mite (HDM)-treated mice compared to the PBS control group. Recently, IL-33 +fibroblasts were found to support ILC2 recruitment during helminth infection. As we have found C3 is critical to maintain IL-33 in these cells, we aim to understand if C3 hiIL-33 +fibroblasts participate in allergy by mediating cellular crosstalk with ILC2s and T cells during type 2 immune responses. Supported by grants from NIH R01AI27644 and the Johns Hopkins Catalyst Award to Dr. Stephane Lajoie.

Effects of injection rates and tissue diffusivity in magnetic nano-particle hyperthermia.

Effects of injection rate and tumor physiology on the diffusion of magnetic nano-particles (MNPs) and temperature profile during magnetic hyperthermia are investigated in this work. The study considers three injection rates (2.5 μL/min, 10 μL/min, and 40 μL/min), and two MNP diffusion coefficients (10-9 m2/s and 10-11 m2/s). The simulation of this physics has been done on 3D tumor surrounded by healthy tissue. Transient MNP distribution in tissue is evaluated using Darcy's flow model and the MNP transport (convection-diffusion) equation. The temperature profile in the tumor model is computed by solving Penne's bioheat transfer equation (PBHTE). Results show tumors with high collagen content (with low MNP diffusivity) are more restrictive towards MNP transport than tumors having low collagen content. Thus, tumors with low MNP diffusivity need a higher injection rate to increase the homogeneity of MNP concentration as well as temperature profile during thermo-therapy. Results also show that, MNP fluid injected with a higher injection rate produces a more uniform MNP concentration up to greater depth than the lower injection rate.

Glycocalyx-targeted therapy ameliorates age-related arterial dysfunction.

Advanced age is accompanied by arterial dysfunction, as well as a diminished glycocalyx, which may be linked to reduced high molecular weight-hyaluronan (HMW-HA) synthesis. However, the impact of glycocalyx deterioration in age-related arterial dysfunction is unknown. We sought to determine if manipulations in glycocalyx properties would alter arterial function. Tamoxifen-induced hyaluronan synthase 2 (Has2) reduction was used to decrease glycocalyx properties. Three weeks post-tamoxifen treatment, glycocalyx thickness was lower in Has2 knockout compared to wild-type mice (P<0.05). Has2 reduction induced arterial dysfunction, demonstrated by impaired endothelium-dependent dilation (EDD) and elevated aortic stiffness (P<0.05). To augment glycocalyx properties, old mice received 10 weeks of a glycocalyx-targeted therapy via Endocalyx™ (old+ECX), which contains HMW-HA and other glycocalyx components. Compared to old control mice, glycocalyx properties and EDD were augmented, and aortic stiffness decreased in old+ECX mice (P<0.05). Old+ECX mice had a more youthful aortic phenotype, demonstrated by lower collagen content and higher elastin content than old control mice (P<0.05). Functional outcomes were repeated in old mice that underwent a diet supplemented solely with HMW-HA (old+HA). Compared to old controls, glycocalyx properties and EDD were augmented, and aortic stiffness was lower in old+HA mice (P<0.05). We did not observe any differences between old+HA and old+ECX mice (P>0.05). Has2 reduction phenocopies age-related arterial dysfunction, while 10 weeks of glycocalyx-targeted therapy that restores the glycocalyx also ameliorates age-related arterial dysfunction. These findings suggest that the glycocalyx may be a viable therapeutic target to ameliorate age-related arterial dysfunction.

Toughness Variations among Natural Casings: An Exploration on Their Biochemical and Histological Characteristics.

We investigated the mechanical, biochemical, and histological properties of hog and sheep casings produced in different countries to elucidate the responsible factors for the toughness quality of natural casings. The toughness and collagen characteristics of sheep and lamb casings were also investigated to elucidate the effect of animal slaughter age on the relationships between connective tissue and the mechanical properties of natural casings. The results showed that the main component of hog and sheep casings was collagen with many layers of sheets. The contents of collagen, elastin, and proteoglycan in hog and sheep casings were similar. The toughest Chinese casings (p < 0.01) possessed a significantly lower heat solubility of collagen (p < 0.01), and a different size and arrangement of collagen fibers. Sheep casings were significantly tougher than lamb casings (p < 0.01). Compared with lamb casings, sheep casings had a significantly low heat-labile collagen content, a low heat solubility of collagen, a large size of collagen fibers, and a high pyridinoline concentration (p < 0.01). Therefore, the high thermal and structural stability of collagen in aged animals may contribute to the enhanced mechanical properties of casings.

Differences in texture and digestive properties of different parts in boiled abalone muscles

Differences in texture and digestive properties of different parts in 80 °C-boiled abalone muscle (adductor and transition part) after different processing time were investigated. With the extension of boiling time, the shear force and hardness of adductor increased first (6 min) and then decreased (30 min and 240 min), while the two indexes of transition part dramatically decreased after boiling for 6 min and then maintained until 240 min. Meanwhile, for adductor, the degree of protein hydrolysis, protein digestibility, and peptide transport levels declined with the extension of boiling time; While for transition part, those protein digestion and transport indexes significantly decreased first (6 min and 30 min) and then increased (240 min). By contrast, the adductor contained higher myofibrillar proteins content but lower collagen content than the transition part, which contributed to the differences in texture and digestive properties of the boiled samples.

Immunity and Extracellular Matrix Characteristics of Breast Cancer Subtypes Based on Identification by T Helper Cells Profiling.

BackgroundThe therapeutic effect of immune checkpoint inhibitors on tumors is not only related to CD8+ effector T cells but also sufficiently related to CD4+ helper T (TH) cells. The immune characteristics of breast cancer, including gene characteristics and tumor-infiltrating lymphocytes, have become significant biomarkers for predicting prognosis and immunotherapy response in recent years.MethodsBreast cancer samples from The Cancer Genome Atlas (TCGA) database and triple-negative breast cancer (TNBC) samples from GSE31519 in the Gene Expression Omnibus (GEO) database were extracted and clustered based on gene sets representing TH cell signatures. CIBERSORT simulations of immune cell components in the tumor microenvironment and gene set enrichment analyses (GSEAs) were performed in the different clusters to verify the classification of the subtypes. The acquisition of differentially expressed genes (DEGs) in the different clusters was further used for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. The clinical information from different clusters was used for survival analysis. Finally, the surgical tissues of TNBC samples were stained by immunofluorescence staining and Masson’s trichrome staining to explore the correlation of TH cell subtypes with extracellular matrix (ECM).ResultsThe breast cancer samples from the datasets in TCGA database and GEO database were classified into TH-activated and TH-silenced clusters, which was verified by the immune cell components and enriched immune-related pathways. The DEGs of TH-activated and TH-silenced clusters were obtained. In addition to TH cells and other immune-related pathways, ECM-related pathways were found to be enriched by DEGs. Furthermore, the survival data of TCGA samples and GSE31519 samples showed that the 10-year overall survival (p-value < 0.001) and 10-year event-free survival (p-value = 0.162) of the TH-activated cluster were better, respectively. Fluorescent labeling of TH cell subtypes and staining of the collagen area of surgical specimens further illustrated the relationship between TH cell subtypes and ECM in breast cancer, among which high TH1 infiltration was related to low collagen content (p-value < 0.001), while high TH2 and Treg infiltration contained more abundant collagen (p-value < 0.05) in TNBC. With regard to the relationship of TH cell subtypes, TH2 was positively correlated with Treg (p-value < 0.05), while TH1 was negatively correlated with both of them.ConclusionsThe immune and ECM characteristics of breast cancer subtypes based on TH cell characteristics were revealed, and the relationship between different TH cell subsets and ECM and prognosis was explored in this study. The crosstalk between ECM and TH cell subtypes formed a balanced TME influencing the prognosis and treatment response in breast cancer, which suggests that the correlation between TH cells and ECM needs to be further emphasized in future breast cancer studies.

Abstract 310: MRI Characterization Of Thrombus For Differentiating Acute And Chronic Dvt

Background: Optimal patient selection for the endovascular treatment of iliofemoral DVTs remains a significant clinical challenge. 2 Symptom onset is used as a gross surrogate for determining the composition of the clot to determine if it is amenable to endovascular treatment. As thrombus ages, collagen deposition increases, and the bulk of fibrin within the thrombus becomes crosslinked and resistant to lysis 3 . Symptom onset has poor correlation with collagen content 4 and is not a predictor of endovascular success. The goal of this study is to relate MRI characteristics to clot composition to guide patient selection for endovascular treatment of iliofemoral DVT in the future. 5 Methods: 2 patients with popliteal deep venous thrombus that presented within a week of symptom onset underwent Inari thrombectomy. Patient 1 was imaged in the 7T MRI and patient 2 was imaged with 3T Both patients had T2-weighted (T2W) and UTE sequences. Results: Patient 1 had a thrombus with high collagen content indicated by low signal intensity on T2W imaging and high signal intensity on UTE MRI. The extracted clot had gross chronic characteristics and was extremely challenging to extract despite multiple passes. Patient 2 had a thrombus with low collagen content indicated by low signal intensity on T2W imaging and isointense on ultrashort echo time imaging. The clot had acute gross characteristics and was easy to extract. Conclusion: Symptom onset is not always reflective of the composition of deep venous thrombus. MRI characterization of thrombus can aid patient selection for endovascular treatment by differentiating patients with high and low collagen content.

Microfluidic-preparation of PLGA microcarriers with collagen patches for MSCs expansion and osteogenic differentiation

This study was aimed to develop a capillary-based microfluidic methodology for preparing poly (lactic-co-glycolic acid) (PLGA) microcarriers patterned with collagen patchy structure (PLGA-Col), which are superior in enhancing proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs) seeded on them. Primary W/O emulsions were first prepared using aqueous collagen and PLGA solutions. A two-phase microfluidic device was then designed and the emulsions were used as the inner liquid phase to obtain PLGA-Col microcarriers. The content of collagen was varied to yield PLGA-Col-L (lower collagen content) and PLGA-Col-H (higher collagen content). The proliferation behavior of the cells on the microcarriers was evaluated by live/dead cell staining and CCK-8 assays, while the osteogenic differentiation behavior was evaluated by ALP and qRT-PCR assays. Pristine PLGA microcarriers were also prepared to serve as a control. Three groups, PLGA, PLGA-Col-L, and PLGA-Col-H were then obtained. PLGA-Col was asymmetric with a rough/porous collagen patchy structure. All of these microcarriers could maintain morphology integrity for at least 3 weeks in the aqueous medium before undergoing obvious swelling (5w) and further erosion (7w). It was demonstrated that PLGA-Col could not only enhance the MSCs adhesion/proliferation but also mediate their subsequent osteogenic differentiation. PLGA-Col-L was suitable for supporting the MSCs proliferation, while PLGA-Col-H was more efficient in promoting the osteogenic differentiation of MSCs. Hence, the incorporation of collagen as a patchy structure into PLGA microspheres through the current microfluidic method could be an effective strategy to provide a superior type of microcarriers with well-defined functionality.

Effects of morphometric and biochemical parameters on collagen and pepsin-solubilized collagen yields of Holothuria tubulosa (Gmelin, 1790) and Holothuria (Roweothuria) poli (Delle Chiaje, 1823)

Due to their unique biochemical composition, sea cucumbers are highly prized marine echinoderm species. One of their most important properties is that they contain a high amount of collagen in their body wall. In this study, the relationship between collagen and pepsin-solubilized collagen yields from Holothuria tubulosa and Holothuria poli and morphometric and biochemical parameters were investigated.&#x0D; Collagen yields were in the range of 10.63–16.04% for H. tubulosa and 7.12–13.10% for H. poli. It was determined that they may be related to length, body wall weight, and biochemical composition at different length frequencies. Moreover, maturity may have a direct effect on the yield, as mature specimens were found to have lower content of collagen, whereas immature small specimens contained a higher percentage of collagen. It was found that with increasing pepsin concentration, the PSC yield increased to 1.83–1.89% in H. tubulosa and H. poli, respectively. It was determined that collagen from smaller individuals, which contained more moisture and ash, was likely more susceptible to pepsin hydrolyzation.&#x0D; This is the first published study demonstrating that collagen yield of sea cucumbers can vary with length, weight, maturity, and biochemical composition, in addition to species-specific differences.

Histological composition, physiochemical parameters, and organoleptic properties of three muscles from Fleckvieh bulls and heifers

The histochemical characteristics, physical attributes, chemical composition, and sensory profile of three muscles (longissimus thoracis et lumborum – LTL, rectus abdominis – RA, triceps brachii – TB) from Fleckvieh (N = 24) bulls and heifers were compared. Samples of each muscle were taken within 1 h of slaughter to assess muscle fibre traits, while physio-chemical meat quality was assessed in each muscle at 48 h post mortem, followed by the sensory assessment of the muscles after 7 days of ageing. Despite identical raising conditions, bulls showed more favourable growth and slaughter performance, but heifers produced meat with more favourable sensory characteristics, as a result of a higher proportion of IIB fibres in their muscles, as well as a higher intramuscular fat content, and lower collagen content.