Density Of Collagen Fibers Research Articles

Fibroblast alignment and matrix remodeling induced by a stiffness gradient in a skin-derived extracellular matrix hydrogel

Large skin injuries heal as scars. Stiffness gradually increases from normal skin to scar tissue (20x higher), due to excessive deposition and crosslinking of extracellular matrix (ECM) mostly produced by (myo)fibroblasts. Using a custom mold, skin-derived ECM hydrogels (dECM) were UV crosslinked after diffusion of ruthenium (Ru) to produce a Ru-dECM gradient hydrogel. The Ru diffusion gradient equates to a stiffness gradient and models physiology of the scarred skin. Crosslinking in Ru-dECM hydrogels results in a 23-fold increase in stiffness from a stiffness similar to that of normal skin. Collagen fiber density increases in a stiffness-dependent fashion while stress relaxation also alters, with one additional Maxwell element necessary for characterizing Ru-dECM. Alignment of fibroblasts encapsulated in hydrogels suggests that the stiffness gradient directs fibroblasts to orientate at ∼45 ° in regions below 120 kPa. In areas above 120 kPa, fibroblasts decrease the stiffness prior to adjusting their orientation. Furthermore, fibroblasts remodel their surrounding ECM in a gradient-dependent fashion, with rearrangement of cell-surrounding ECM in high-stiffness areas, and formation of interlaced collagen bundles in low-stiffness areas. Overall, this study shows that fibroblasts remodel their local environment to generate an optimal ECM mechanical and topographical environment. Statement of significanceThis study developed a versatile in vitro model with a gradient stiffness using skin-derived ECM hydrogel with unchanged biochemical environment. Using Ruthenium crosslinking, a 20-fold stiffness increase was achieved as observed in fibrotic skin.The interaction between fibroblasts and matrix depends on changes in the matrix stiffness. The stiffness gradient directed the alignment of fibroblasts with ∼45° in regions with≤ 120 kPa. The cells in regions with the higher stiffness decreased stiffness first and then oriented themselves. Furthermore, fibroblasts remodeled surrounding ECM and regulated its mechanics in a gradient-dependent fashion to reach an optimal condition.Our study highlights the dynamic interplay between cells and surrounding matrix, shedding light on potential mechanisms and strategies to target scar formation and remodeling.

Histological Changes of Porcine Animal Skin with Micro-focused Ultrasound.

As a noninvasive alternative therapy, microfocused ultrasound (MFU) has become a research hotspot in recent years for its potential to enhance skin laxity. While several clinical studies have explored the effects of MFU on improving skin laxity, there is limited literature available on the histological changes resulting from MFU treatments. It has been established that the skin structure and composition of the Bama miniature pigs closely resembles that of humans, including collagen content, type I collagen distribution, and elastin distribution. This study primarily focuses on examining the histological alterations in the skin tissue of Bama miniature pigs following MFU application. We also selected some typical clinical photographs of patients treated with MFU and compared the clinical effects with histological changes observed in porcine skin. The MFU device utilized in this study incorporates ultra-pulse technology and large focal area technology. Following the standard operating procedures provided by the manufacturer, different handles were used in different skin area of pigs. Biopsies were obtained immediately after treatment and 1 month after treatment. Significant histological changes were observed in the Bama miniature pigs skin, including collagen contraction and fragmentation, dilation and congestion of superficial dermal capillaries immediately after MFU treatment; dermal thickening, increased thickness and density of collagen fibers, elevated levels of elastin and type I collagen, as well as thickened fiber septa in the adipose layer 1 month later. These histological results corresponded to clinical findings in human, such as facial redness and swelling immediately after treatment, and improvement in facial relaxation after approximately 1 month after treatment. Collectively, these histological findings provide valuable evidence supporting the clinical application of MFU for enhancing skin laxity. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Collagen and elastic fibers assessment of the human heart valves for age estimation in Thais using image analysis.

The study investigated the relationship between the histological compositions of the tricuspid, pulmonary, mitral, and aortic valves, and age. All 85 fresh human hearts were obtained with an age range between 20 and 90years. The central area of the valves was conducted to analyze the density of collagen and elastic fibers by using an image analysis program. Neural network function in MATLAB was used for classification data and accuracy test of the age predictive model. Overall, a gradual increase in the density of collagen and elastic fibers was demonstrated with age in all valve types. The pulmonary valve cusps had the least density of collagen and elastic contents, whereas the most dense of collagen was found in the mitral leaflets. A similarity was noted for the elastic fibers in the tricuspid, mitral, and aortic valves. The highest correlation between the collagen (r = 0.629) and elastic fibers (r = 0.713) and age was found in the noncoronary cusp of the aortic valve. The established predictive equations using collagen and elastic fibers in the noncoronary cusp provided the standard error of ± 14.0 and 12.5years, respectively. A 60.9% of accuracy was found in all age groups using collagen, while accuracy in elastic fibers showed 70.0% in the classification process using the neural networks. The current study provided additional data regarding age-associated changes of collagen and elastic fibers in the human heart valves in Thais and the benefits and application in age forensic identification.

Collagen molecular organization preservation in human fascia lata and periosteum after tissue engineering.

Large bone defect regeneration remains a major challenge for orthopedic surgeons. Tissue engineering approaches are therefore emerging in order to overcome this limitation. However, these processes can alter some of essential native tissue properties such as intermolecular crosslinks of collagen triple helices, which are known for their essential role in tissue structure and function. We assessed the persistence of extracellular matrix (ECM) properties in human fascia lata (HFL) and periosteum (HP) after tissue engineering processes such as decellularization and sterilization. Harvested from cadaveric donors (N = 3), samples from each HFL and HP were decellularized following five different chemical protocols with and without detergents (D1-D4 and D5, respectively). D1 to D4 consisted of different combinations of Triton, Sodium dodecyl sulfate and Deoxyribonuclease, while D5 is routinely used in the institutional tissue bank. Decellularized HFL tissues were further gamma-irradiated (minimum 25kGy) in order to study the impact of sterilization on the ECM. Polarized light microscopy (PLM) was used to estimate the thickness and density of collagen fibers. Tissue hydration and content of hydroxyproline, enzymatic crosslinks, and non-enzymatic crosslinks (pentosidine) were semi-quantified with Raman spectroscopy. ELISA was also used to analyze the maintenance of the decorin (DCN), an important small leucine rich proteoglycan for fibrillogenesis. Among the decellularization protocols, detergent-free treatments tended to further disorganize HFL samples, as more thin fibers (+53.7%) and less thick ones (-32.6%) were recorded, as well as less collagen enzymatic crosslinks (-25.2%, p = 0.19) and a significant decrease of DCN (p = 0.036). GAG content was significantly reduced in both tissue types after all decellularization protocols. On the other hand, HP samples were more sensitive to the D1 detergent-based treatments, with more disrupted collagen organization and greater, though not significant loss of enzymatic crosslinks (-37.4%, p = 0.137). Irradiation of D5 HFL samples, led to a further and significant loss in the content of enzymatic crosslinks (-29.4%, p = 0.037) than what was observed with the decellularization process. Overall, the results suggest that the decellularization processes did not significantly alter the matrix. However, the addition of a gamma-irradiation is deleterious to the collagen structural integrity of the tissue.

A bone-targeting permeable nanomicelle acting as an icebreaker for enhancing chemotherapy of osteosarcoma

Osteosarcoma is one of the commonest malignant bone tumors in children and adolescents, and its preferred treatment is chemotherapy. However, the lack of sufficient blood vessels in the bone tissue and the dense collagen fibers in osteosarcoma severely weaken the drug-directional accumulation effect and intra-tumoral penetration, leading to poor therapeutic efficacy. Herein, we reported a bone-targeted permeable nanomicelle (Co1-PTX@DSAA) composed of aspartic acid (Asp)-modified dextran (DSAA) to deliver paclitaxel (PTX) and collagenase 1 (Co1) simultaneously for highly effective osteosarcoma treatment. The prepared nanomicelle possessed excellent osteosarcoma targeting ability as Asp can combine with hydroxyapatite (HAP) in bone. More intelligently, the surface-absorbed Co1 endowed PTX@DSAA with a special function like a nano-icebreaker, which could quickly destroy the collagen fibers to promote PTX penetration deeply in the tumor. Our work suggests that Co1-PTX@DSAA nanomicelles could quickly combine with HAP and Ca2+ at an adsorption rate of ∼ 60% and ∼ 32%, respectively. Meanwhile, the penetration depth of Co1-PTX@DSAA could even reach 70 μm in the multicellular spheroids (MCSs) model. The tumor treatment efficiency of Co1-PTX@DSAA is 1.51 times that of free PTX. Overall, this unprecedented nanomicelle can simultaneously facilitate drug accumulation and deep penetration in the tumor, which will provide a promising strategy for future safe and high-efficiency clinical osteosarcoma treatment.

Effect on Endoplasmic Reticulum Stress of the Combined Oral Contraceptives in the Liver

Objective: We aimed to evaluate the effects of combined oral contraceptive active ingredients ethinylestradiol, drospirenone, and ethinylestradiol+drospirenone for histopathological changes, and endoplasmic reticulum stress levels in the liver.
 
 Methods: In the study, 37 to 8-week-old Balb/c female mice were used. Mice were randomly divided into the control, sham, ethinylestradiol, drospirenone, and ethinylestradiol+drospirenone groups. Experimental groups were administered ethinylestradiol, drospirenone, and ethinylestradiol+drospirenone with gavage for 35 days. In liver tissue sections, histopathological changes were detected with hematoxylin&eosin, orcein, Mallory's Azan, and periodic acid-Schiff, and the presence of endoplasmic reticulum stress was detected by Chop and Grp78 immunostaining.
 
 Results: The ethinylestradiol+drospirenone group showed significant histopathological changes compared to the control group. Some degenerative changes were noted such as swelling and size differences in hepatocytes in the ethinylestradiol+drospirenone group. When compared to the control group, an increased collagen and elastic fibers density around the vena centralis was observed in the ethinylestradiol+drospirenone group. The expression level of Grp78 protein in female mice given ethinylestradiol+drospirenone was statistically significantly increased compared to the control group. The expression level of Chop protein was significantly increased in the ethinylestradiol, drospirenone, and ethinylestradiol+drospirenone groups. 
 
 Conclusion: We concluded that the use of combined oral contraceptives increases endoplasmic reticulum stress in mouse liver tissue, and as a result, it may cause liver histopathological disorders by promoting cell death.

Polarization-Sensitive OCT Imaging of Scleral Abnormalities in Eyes With High Myopia and Dome-Shaped Macula

The relevance of visualizing scleral fiber orientation may offer insights into the pathogenesis of pathologic myopia, including dome-shaped maculopathy (DSM). To investigate the orientation and density of scleral collagen fibers in highly myopic eyes with and without DSM by polarization-sensitive optical coherence tomography (PS-OCT). This case series included patients with highly myopic eyes (defined as a refractive error ≥6 diopters or an axial length ≥26.5 mm) with and without a DSM examined at a single site in May and June 2019. Analysis was performed from September 2019 to October 2023. The PS-OCT was used to study the birefringence and optic axis of the scleral collagen fibers. The orientation and optic axis of scleral fibers in inner and outer layers of highly myopic eyes were assessed, and the results were compared between eyes with and without a DSM. A total of 72 patients (51 [70.8%] female; mean [SD] age, 61.5 [12.8] years) were included, and 89 highly myopic eyes were examined (mean [SD] axial length, 30.4 [1.7] mm); 52 (58.4%) did not have a DSM and 37 (41.6%) had a DSM (10 bidirectional [27.0%] and 27 horizontal [73.0%]). Among the 52 eyes without DSM, the 13 eyes with simple high myopia had primarily inner sclera visible, displaying radially oriented fibers in optic axis images. In contrast, the entire thickness of the sclera was visible in 39 eyes with pathologic myopia. In these eyes, the optic axis images showed vertically oriented fibers within the outer sclera. Eyes presenting with both horizontal and bidirectional DSMs had clusters of fibers with low birefringence at the site of the DSM. In the optic axis images, horizontally or obliquely oriented scleral fibers were aggregated in the inner layer at the DSM. The vertical fibers located posterior to the inner fiber aggregation were not thickened and appeared thin compared with the surrounding areas. This study using PS-OCT revealed inner scleral fiber aggregation without outer scleral thickening at the site of the DSM in highly myopic eyes. Given the common occurrence of scleral pathologies, such as DSM, and staphylomas in eyes with pathologic myopia, recognizing these fiber patterns could be important. These insights may be relevant to developing targeted therapies to address scleral abnormalities early and, thus, mitigate potential damage to the overlying neural tissue.

Comparison of the Effectiveness of Methods for Obtaining and Application the Stromal-Vascular Fraction of Adipose Tissue in an Experimental Model of a Donor Wound in Burns

Introduction. The optimal method of obtaining and application a stromal-vascular fraction (SVF) of adipose tissue in the treatment of donor wounds in burned patients has not been determined.Objective — to compare the effectiveness of the stromal-vascular fraction of adipose tissue in the treatment of donor wounds, depending on the method of obtaining (mechanical and enzymatic) and the injection (subdermal, intradermal) into the tissue.Material and methods. Wistar rats (n = 30) were divided into 2 investigated groups: in the first group (eSVF) enzymatic processing of adipose tissue (n = 10) was used, in the second group (mSVF) mechanical processing was used (n = 10). Another 10 rats were used as adipose tissue donors’ group. A deep burn was created in all animals, and after 4 days two more donor wounds were created by taking a split thickness skin autograft: the stromal-vascular fraction was injected intradermally into one of the wounds, subdermally into the other. After 14 days, the area of epithelialization, the microcirculation index and the histological microstructure of the skin were evaluated.Results. The proportion of completely epithelized donor wounds in the eSVF-group was 85 %, in the mSVF-group — 55 % (p < 0.05). The index of microcirculation significantly decreased after intradermal injections in the eSVF-group (p < 0.01), and after subdermal injections — in the mSVF-group (p < 0.05). According to histomorphometry, with intradermal injections of eSVF, the thickness of the epidermis and the layer of granulation tissue is less than in the mSVF group (p < 0.01). At the same time, the relative density of collagen fibers in the granulation tissue was significantly higher after the injections of eSVF than after mSVF (p < 0.01). Comparison of injections of the stromal-vascular fraction showed: no significant differences were found when using eSVF; when using mSVF, the subdermal injections are preferable, since it was accompanied by a significantly lower thickness of granulation tissue (p < 0.01).Conclusions. The enzymatically obtained stromal-vascular fraction of adipose tissue has advantages over the mechanically obtained one: the efficiency of eSVF is equally high when used with intradermally and subdermally injections, which are confirmed by the structure and blood circulation in the newly formed skin. When using mSVF, intradermal injections are the least effective, and subdermal injections are accompanied by a moderately pronounced positive dynamic in the microstructure of the skin of donor wounds.

The Effect of Cocoa Pod Husk (Theobroma cacao L.) Extract on Increasing Gingival Fibroblast and Collagen Density in Wistar Rats Induced by Porphyromonas gingivalis

Periodontal disease is an inflammatory disease of the oral cavity which characterized by inflammation of the gingiva. Theobroma cacao L. is a herbal plant that has antibacterial and anti-inflammatory effects, which is starting to be widely researched as an alternative therapy for inflammation in the oral cavity. The aim of this study was to examined the effect of the ethanol extract gel of cocoa pod husk (Theobroma cacao L.) on increasing the number of fibroblasts and the collagen fiber density in the gingiva of rats that have been induced by Phorphyromonas gingivalis. The sample used 24 male Wistar rats divided into 3 groups. Each group was induced by porphyromonas gingivalis every 3 days for 14 days then anointed with placebo gel (negative control group), metronidazole gel (positive control group), and cocoa pod ethanol extract gel (CPH gel) for 7 and 14 days. Gingival tissue was taken after euthanasia, after which histological preparations were made, and fibroblasts were observed under a microscope and analyzed using quantitative pathology 0.3.2 software, while for collagen density analized using Adobe Photoshop CS6 software. The results showed there was a significant difference of the number of fibroblasts between each group (p<0.05). however there was no significant difference between positive control and cocoa pod husk extract at day 14 (p > 0.05).The treatment group on day 7 and 14 was higher than the other groups. It was conclude that the ethanol extract of cacao pod husk (Theobroma cacao L.) potential to increase the number of fibroblasts and collagen fibers density in gingival tissue of periodontitis rats.

270 Radiologic diagnosis of Extranodal Extension (ENE) in patients with HPV-positive oropharyngeal cancer: consensus diagnosis and influence on prognosis

Tumor often progresses through the weakest part of any surrounding tissues. The extent of tumor invasion depends on: a. Aggressiveness of the tumor cells (e.g. number and invasive character of stem cells), b. robustness of the surrounding tissues and their composition (e.g. vessels), and c. time to allow the tumor to proliferate. The lymph node (LN) capsule comprises dense connective tissue stroma and collagenous fibers, and is a natural barrier that generally prevents further tumor progression. Permeation of tumor through the nodal capsule into surrounding tissues is termed “extranodal extension”. The idiosyncratic and inconsistent mechanism of ENE is imprecisely understood, but it is thought to be due to either tumor cell proliferation that outpaces the capacity of nodal capsular expansion (“ruptures” the LN capsule), or factors within the tumor or tumor microenvironment that facilitate the “breach” of the capsule. The latter might explain ENE in small LNs, or a “neglected” tumor (lengthy intranodal tumor growth with eventual “rupture” through an expanded nodal capsule). Several biomarkers (e.g. podoplanin) that are often associated with tumor aggressiveness have been reported to have a high expression in ENE+ LN. ENE represents a spectrum of tumor nodal invasion. The early sign of ENE can only be visible under the microscope (pathologic ENE); when ENE progresses further, the radiographic signal changes become apparent, making it visible on imaging (iENE). Most advanced ENE causes emergence of clinical surrogates (e.g. peau d'orange, or a “fixed” nodal mass), rendering it detectable by regular clinical examination (ENEc). iENE has been reported to be one of the strongest anatomic prognostic factors for overall survival (mainly due to increased risk of distant metastasis) in HPV-positive oropharyngeal carcinoma (HPV+ OPC), and is able to identify a subgroup of stage I disease with poor prognosis. Several deintensification trials (NRG-HN002, ORATOR, ORATOR2, E3311) have excluded HPV+ OPC with some form of iENE from trial enrolment. Several authors have proposed that iENE be included in future clinical N classification for HPV+ OPC. However, adoption of iENE in clinical care remains challenging because it is not a well-defined radiologic feature among the radiology community. Various definitions / descriptions of iENE have been used in literature. There is also insufficient awareness of the prognostic importance of this parameter in head and neck oncology community. The international iENE Expert Panel was convened under the HNCIG comprised expert internationally renowned neuroradiologists and clinicians. Several rounds of Delphi process were conducted to consolidate iENE definition. The consensus recommendations on the terminology and diagnostic criteria for iENE were generated. The experts in the consensus process recognized the following as criteria for the diagnosis of iENE: clear evidence of irregular or indistinct nodal margin/border; extension into perinodal fat; extension into adjacent structures, and conglomerate/matted/coalescent nodes. These recommendations have been endorsed by 19 national organisations, representing 34 countries. With increased awareness and consolidated definition as well as training, iENE could become an important baseline factor for risk stratification and staging in HPV+ OPC.

Potential Analysis of Belimbing Wuluh (Averhoe bilimbi L.) leaf extract on increasing Fibroblasts, TGFß1 expression and density of Collagen fibers in the Periodontal ligament during Orthodontic Tooth Movement

Background: Orthodontic treatment is a treatment to correct malocclusion. The periodontal ligament plays an important role in preventing recurrence after orthodontic treatment. Fibroblast cells play a role in the regeneration of the periodontal ligament to maintain the stability of orthodontic treatment. Fibroblast cells play a role in the formation of collagen fibers that will connect teeth to bones. TGFß1 is a growth factor that plays a role in inducing the proliferation and transformation of fibroblasts into myofibroblasts and stimulates the accumulation of matrix proteins, including laminin, collagen 1 and 3, and fibronectin. Orthodontic treatment takes a long time so we need a method to speed it up. Belimbingwuluh leaf extract (Averrhoa bilimbi L.) contains antioxidants and anti-inflammatories which are expected to increase the number of fibroblasts and the density of collagen fibers. Objective : To analyze the potential of belimbingwuluh leaf extract in increasing the number of fibroblasts, TGFß1 expression and collagen fiber density during orthodontic tooth movement. Method: using 36 rats divided into 6 groups. The control group was fitted with orthodontic appliances without extracts, and the treatment group was fitted with orthodontic appliances and starfruit leaf extract for 7 days, 14 days and 21 days. An orthodontic appliance in the form of a closed coil spring Ni-Ti was installed to move the maxillary first molars mesially with orthodontic mechanical force. Histological preparations were made on M1 RA teeth with their periodontal ligament, then the tissue was stained with HE to observe fibroblasts, and Trichome Mallory staining for collagen fiber density and immunohistochemical staining to examine TGFß1 expression. Observation of fibroblasts and TGFß1 expression using a microscope and collagen density were observed using a microscope using the Adobe CS 6.0 application. Results: showed a significant increase in the number of fibroblasts, TGFß1 expression and density of collagen fibers in the 7, 14 and 21 day treatment group compared to the control group (p<0.05). Conclusion: BelimbingWuluh leaf extract increases fibroblasts, TGFß1 expression and collagen fiber density in the periodontal ligament during orthodontic tooth movement.

The role, safety, and efficacy of hyperbaric oxygen therapy in aesthetic practice-An evidence-based review.

Hyperbaric oxygen therapy (HBOT) involves patients breathing 100% oxygen in a pressurized chamber, above 1 atmosphere. Many centers are now promoting the use of HBOT for skin rejuvenation. However, the current indications for HBOT do not encompass aesthetic applications. The aim of this evidence-based review was to assess the existing literature regarding the utilization of HBOT in medical aesthetics and rejuvenation, evaluate its effectiveness and safety, and conduct a cost analysis. PubMed Interface, Cochrane Library, Google Scholar, and Embase searches were carried out. The Best Bets methodology was used, and the risk of bias was appraised using the Quality Assessment Tool for Quantitative Studies. This review included a total of 17 human studies with a total of 766 participants. Three studies were classified as level II evidence, three studies were of level III evidence, and 11 were of level IV evidence. All the included studies were judged at high risk of bias. The most relevant findings supported by level II evidence were that HBOT decreased the shedding rate post-FUE hair transplant (27.6 ± 2.6% vs. 69.1 ± 2.4%) but this did not affect the final outcome between HBOT (96.9 ± 0.5%) and the control (93.8 ± 0.6%). Moreover, level III evidence demonstrated that following HBOT, there was a significant increase in elastic fiber length (p ≤ 0.0001, effect size = 2.71) and a significant decrease in fiber fragmentation (p = 0.012). There was also a significant increase in collagen fiber density following HBOT (p = 0.0001, effect size = 1.10). However, there was no significant effect of antioxidant vitamins A, C, and E with HBOT. The inflammatory response significantly decreased after 7 days of HBOT with a decreased expression of IL-12p40, MIP-1β, and PDGF-BB and a higher expression of IL-1Ra. Moreover, HBOT was used prophylactically prior to abdominoplasty to decrease the risk of complications. In this study, complications were decreased from 32.6% (89 patients) to 8.4% (7 patients) with a p < 0.001, and in a multivariate analysis, preoperative HBOT was an independent protective factor against postoperative complications (p < 0.001). There is conflicting evidence on how the method of action of HBOT can have a beneficiary effect in aesthetic and whether the treatment is justifiable. To our knowledge, this is the first comprehensive review discussing the available evidence regarding the use of HBOT in many aesthetic clinical scenarios, including preventive, medical, and surgical settings. However, randomized clinical trials with longer follow-up and better patient selection are needed to be able to generate a reliable conclusion.

Biomechanical and histological evaluation of aspirin in rotator cuff tear rat model.

Background: Aspirin is a representative non-steroidal anti-inflammatory drug (NSAIDs) and has been commonly used for the treatment of tendinopathy in clinical practice. In this study, we aimed to evaluate the biomechanical and histological healing effects of aspirin on the healing of the tendon-to-bone interface after rotator cuff tear repair. Methods: A total of 20 male Sprague-Dawley rats were randomly divided into two groups of 10 rats each. Group-C performed repaironly, and group-aspirin treated with aspirin after tendon repair. Group-aspirin rat were intraperitoneally injected with aspirin at 10mg/kg every 24h for 7days. Eight weeks after surgery, the left shoulder of each rat was used for histological analysis and the right shoulder for biomechanical analysis. Results: In the biomechanical analysis, there was no significant difference in load-to-failure (group-C: 0.61 ± 0.32N, group-aspirin: 0.74 ± 0.91N; p = .697) and ultimate stress (group-C: 0.05 ± 0.01MPa, group-aspirin: 0.29 ± 0.43MPa; p = .095). For the elongation (group-C: 222.62 ± 57.98%, group-aspirin: 194.75 ± 75.16%; p = .028), group-aspirin confirmed a lower elongation level than group-C. In the histological evaluation, the Bonar score confirmed significant differences in collagen fiber density (group-C: 1.60 ± 0.52, group-aspirin: 2.60 ± 0.52, p = .001) and vascularity (group-C: 1.00 ± 0.47, group-aspirin: 2.20 ± 0.63, p = .001) between the groups. Conclusions: Aspirin injection after rotator cuff tear repair may enhance the healing effect during the early remodeling phase of tendon healing.

The healing effect of a mixture of Arnebia euchroma and animal fat on burn wounds in rats in comparison with sulfadiazine.

Thermal burn is a serious cause of morbidity and mortality that affects millions of people worldwide. The aim of this experimental study was to investigate the efficacy of Arnebia euchroma (AE) to treat burn wounds in a rat model. A total of 80 male rats (200-250g) were shaved over the back of the neck (2×3cm2) and a second-degree burn wound was induced at this site under general anaesthesia. The rats were then randomly assigned to one of four groups (each n=20) and the burns were treated daily for 14 days as follows: (1) dressed with animal fat; (2) dressed with sulfadiazine; (3) dressed with a mixture of AE and animal fat; (4) no treatment (control). Five rats from each group were sacrificed on days 3, 5, 9 and 14 post-burn and the wounds were evaluated histologically and immunohistochemically for the expression of interleukin (IL)-1 and IL-6. There was a significant increase at day 3 and decrease on day 5 samples for the expression of IL-1 in the AE plus fat group and IL-6 in the AE plus fat and sulfadiazine groups, compared to the control and fat treatment groups, respectively. Both AE plus fat and sulfadiazine treatments reduced inflammation and granulation tissue formation by day 5 post-burn, while re-epithelialisation commenced by day 9 post-burn. In addition, burns treated with AE plus fat exhibited keratinised epidermis, associated with regular collagen fibres, compared to moderately dense collagen fibres without vascularisation in the sulfadiazine group. These findings suggested that AE plus fat was superior to sulfadiazine in enhancing burn wound healing in rats.

Assessment of the nano-mechanical properties of healthy and atherosclerotic coronary arteries by atomic force microscopy.

Nano-indentation techniques might be better equipped to assess the heterogeneous material properties of plaques than macroscopic methods but there are no bespoke protocols for this kind of material testing for coronary arteries. Therefore, we developed a measurement protocol to extract mechanical properties from healthy and atherosclerotic coronary artery tissue sections. Young's modulus was derived from force-indentation data. Metrics of collagen fibre density were extracted from the same tissue, and the local material properties were co-registered to the local collagen microstructure with a robust framework. The locations of the indentation were retrospectively classified by histological category (healthy, plaque, lipid-rich, fibrous cap) according to Picrosirius Red stain and adjacent Hematoxylin & Eosin and Oil-Red-O stains. Plaque tissue was softer (p < 0.001) than the healthy coronary wall. Areas rich in collagen within the plaque (fibrous cap) were significantly (p < 0.001) stiffer than areas poor in collagen/lipid-rich, but less than half as stiff as the healthy coronary media. Young's moduli correlated (Pearson's ρ = 0.53, p < 0.05) with collagen content. Atomic force microscopy (AFM) is capable of detecting tissue stiffness changes related to collagen density in healthy and diseased cardiovascular tissue. Mechanical characterization of atherosclerotic plaques with nano-indentation techniques could refine constitutive models for computational modelling.

Regeneration of the apical region of the tooth after the treatment of destructive periodontitis with cement resorption

Aim. Destructive changes in the tissues of the tooth and periodontium entail resorption of the hard tissues of the tooth in the apical region. The goal is to identify morphological changes in root tissues with destructive periodontitis and resorption phenomena after the treatment of the tooth with calcium-containing preparations using a scanning electron microscope. Materials and methods. Examination of teeth treated for destructive forms of periodontitis with apical resorption was performed using a JSM-6490LV scanning electron microscope (JEOL, Japan) with an energy-dispersive attachment INCA Penta FETx3 (OXFORD Instruments, England). Results. In the apical part of the root there is a cellular mixed layered cementum. The dentin and the dentin-cementum junction are highly calcified. On top of them is cellular cement with lacunae of cementoblasts. The relief of the zone of cell-free cement has a wavy structure, consists of dense collagen fibers with a high content of calcium. With external root resorption, we observe extensive destruction of the cementoblast layer. An area of newly formed cementum was found inside the apical foramen. On the apical surface, where the resorption covered the dentin layer, there was an area of newly formed cementum. Its cellular layer consisted of round-shaped cells rising above the tissue of a homogeneous structure, smoothly flowing into the spongy tissue denting the bone. Discussion. It can be assumed that prolonged use of calcium-containing drugs leads to calcification. The presence of dense connective tissue in the periodontium indicates regenerative processes. The control of cement formation remains uncertain. Conclusions. Perhaps we are seeing a reparative atypical regeneration of the cement of the apical part of the tooth root. Dentinal calcification. In the lateral parts of the apical region, there is an outer layer of cementum with no cementoblasts. An increase in the thickness of the cement was noted. It can be assumed that we observe the phenomenon of osteogenesis in the area of strong resorption.

Abstract C020: Unconvering the hidden immunosuppressive landscape in pancreatic ductal adenocarcinoma

Abstract Pancreatic ductal adenocarcinoma (PDA) is one of the deadliest forms of cancer with an extremely low survival rate. Despite the success of therapeutic T cells in hematologic cancers, many solid tumors, including PDA, remain unresponsive with such therapies, partly due to its mechanically complex, dense, and immunosuppressive stroma. Therefore, understanding the dynamic interplay between therapeutic T cells and the tumor microenvironment (TME) is crucial for revealing engineering targets for next-generation immunotherapies. We approach this problem with genetically engineered KPC (KrasLSL-G12D/+; Trp53LSL-R172H/+; Pdx-1-Cre) mouse models that recapitulates PDA disease progression and stromal dynamics. Within live tumor slices from primary tumors, we are defining how stromal components such as dense collagen fiber networks and tumor-associated macrophages (TAMs) orchestrate an immunosuppressive landscape. We employ multiphoton laser scanning microscopy (MPLSM) to generate multiphoton excitation of fluorescence (cell dyes and immunofluorescence) and second harmonic generation (SHG) for collagen fibers to acquire multidimensional data (x, y, z, c, t) of T cell migration and interaction within the TME. We subsequently reveal T cell migration and interaction as a function of its physical and biological ECM components using advanced computer vision and machine learning algorithms based on the Clustered Random Convolutional Kernel Transform (cROCKET), revealing a hidden landscape in the feature space. Perturbations to the TME in KPC mice with CCR2 inhibitor CCX598 (in vivo) and clodronate liposomes (ex vivo) deplete CD11b+ myeloid cells, resulting in altered behaviors of the infiltrating T cells. Anti-PD-1 monoclonal antibody neutralizes the PD-1/PD-L1 axis in T cells, resulting in enhanced migration and infiltration in tumor slices. Citation Format: Guhan Qian, Hongrong Zhang, Aine Knott, Jon Zettervall, Ingunn Stromnes, Paolo Provenzano. Unconvering the hidden immunosuppressive landscape in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr C020.

Prostatic morphological changes throughout life: Cytochemistry as a tool to reveal tissue aging markers.

The prostate undergoes normal or pathological morphological changes throughout life. An understanding of these changes is fundamental for the comprehension of aging-related pathological processes such as benign prostatic hyperplasia (BPH) and cancer. In the present study, we show some of these morphological changes, as well as histochemical techniques like Weigert's resorcin-fuchsin method, Picrosirius Red, and Gömöri's reticulin for use as tools in the study of prostate tissue under light microscopy. For this purpose, prostates of the Mongolian gerbil (n = 9), an experimental model that develops BPH spontaneously, were analyzed at three life stages: young (1 month old), adult (3 months old), and old (15 months old). The results showed that fibrillar components such as collagen, and reticular and elastic fibers, change throughout life. In young animals, the prostate has cuboidal epithelium surrounded by thin layers of smooth muscle, continuous collagen fibers, winding reticular fibers, and sporadic elastic fibers. With adulthood, the epithelium becomes columnar, encircled by compacted muscle cells among slender collagen fibers, elongated reticular fibers, and linear elastic fibers. In aging individuals, the prostate's epithelium stratifies, surrounded by thick muscle layers among dense collagen fibers, disordered reticular fibers, and elastic fibers in different planes. We also identified a few accumulations of lipid droplets and lipofuscin granules in adult animals and high accumulation in old animals evidenced by Oil red O and Gömöri-Halmi techniques, respectively. The histochemical techniques presented here have been demonstrated to be useful and accessible tools in prostate studies. RESEARCH HIGHLIGHTS: Cytochemical techniques to study prostate morphology. The prostate changes with age.

Histological and morphological development of the prepuce from birth to prepubertal age.

To study the histological changes of the preputial tissue from birth to prepubertal age in order to define unnoticed morphological changes. Prepuce samples were obtained from 79 healthy boys who underwent routine ritual circumcision. Specimens were divided into six groups according to the boys' age: newborn, 0-1 year of age, 2-3 years of age, 4-5 years of age, 6-7 years of age, and 8-9 years of age. Histologic analysis of the specimens was performed by H&amp;E, Masson's trichrome, Verhoeff-Von Gieson, immunohistochemical staining. Microscopic examinations showed that average epithelial thickness increased after the neonatal period (p=0.001). When collagen fiber density was evaluated, no significant differences between groups were found (p=0.083). When the elastic fibers in the dermis were evaluated, it was determined that the number and thickness of elastic fibers increased with age. Immunohistochemical examinations showed that the number of peripheral nerves marked with S100 was lower in the neonatal period than at other ages (p=0.048). When the vessels marked with CD105 antibody were counted, there was no significant difference between the groups (p=0.078). This is the first study to examine the age-related structure of connective tissue elements in the foreskin. Our results showed that the prepuce's prepubertal maturation process is continuous, and the first 2 years of life are appropriate not only in relation to the physiological effects of age but also the optimum structural changes for wound healing, such as vessel diameter, epithelium thickness, peripheral nerve count.

EFFECT OF KECEMCEM TREE (SPONDIAS PINNATA) BARK EXTRACT GEL TO INCREASE COLLAGEN POST WISTAR RATS CURETTAGE

Introduction: Periodontal treatment such as curettage and requires adjuvant therapy for healing process. One of the adjuvant therapies used is hyaluronic acid. Recently, several scientific studies have focused on the antioxidant and anti-inflammatory properties of various natural products such as kecemcem tree bark (Spondias pinnata) having a protective effect against oxidative and inflammatory changes that occur during the development of mucositis. This study aims to determine the effect of 70% Spondias pinnata bark extract gel to increase collagen fiber density after curettage on wistar rats. Material and Methods: Wistar rats were divided into 3 groups, negative control (CMC-Na gel), positive control (hyaluronic acid gel), and treatment group (70% Spondias pinnata bark extract gel). Mice were sacrificed and then histological preparations were made for further observation in three fields of view using a 400x magnification light microscope. Results and Discussions: The average collagen density scoring value was higher than the positive control group and the negative control group. The results of the Mann-Whitney U test showed that there was a significant difference (p&lt;0.05). Flavonoids, phenols, and β-sitosterol in kecemcem bark extract (Spondias pinnata) have an effect on increasing the density of collagen fibers after curettage as indicated by the higher average scoring value in the treatment group. Conclusion: It can be concluded that 70% 0% Spondias pinnata bark extract gel has the effect of increasing the density of gingival collagen fibers after curettage in Wistar rats (Rattus norvegicus).