Altered Extracellular Matrix Research Articles

Perspectives on the extracellular matrix in inflammatory bowel disease and bowel decellularization protocols

The extracellular matrix (ECM) is a non-cellular three-dimensional structure present in all tissues that is essential for the intestinal maintenance, function and structure, as well as for providing physical support for tissue integrity and elasticity. ECM enables the regulation of various processes involved in tissue homeostasis, being vital for healing, growth, migration and cell differentiation. Structurally, ECM is composed of water, polysaccharides and proteins, such as collagen fibers and proteoglycans, which are specifically arranged for each tissue. In pathological scenarios, such as inflammatory bowel disease (IBD), the deposition and remodeling of the ECM can be altered in relation to the homeostatic composition. IBD, such as Ulcerative colitis and Crohn’s disease, can be differentiated according to ECM alterations, such as circulating levels of collagen, laminin and vimentin neoepitopes. In this context, ECM presents particularities in both physiological and pathological processes, however, exploring methods of tissue decellularization is emerging as a promising frontier for new therapeutic interventions and clinical protocols, promoting the development of new approaches to intestinal diseases.

Photoaging Decoded: Extracellular Matrix Alterations and Mechanisms via Mitogen-Activated Protein Kinase/Matrix Metalloproteinase, Transforming Growth Factor-β Pathways, and Glycosaminoglycan Metabolism.

Photoaged skin features an appearance of premature aging induced by external factors, mainly ultraviolet (UV) irradiation. Visible aging signs and increased susceptibility to skin-related diseases triggered by UV irradiation have raised widespread concern. As a critical component of human skin, the extracellular matrix (ECM) provides essential structural, mechanical, and functional support to the tissue. Consequently, UV-induced ECM deterioration is a major contributor to photoaging. This review begins by analyzing the structural and functional changes between healthy and photoaged skin in prominent ECM components, including collagens, glycosaminoglycans (GAGs), proteoglycans, basement membrane proteins, and elastic fibers. Furthermore, we explore the key mechanisms driving ECM deterioration in response to UV irradiation, focusing on mitogen-activated protein kinase/matrix metalloproteinase and transforming growth factor-β/Smad signaling pathways, as well as the synthesis and degradation of GAGs. A comprehensive understanding of these changes and underlying mechanisms is crucial for elucidating the biological influence of UV on the ECM, ultimately providing more reliable evidence for the prevention and treatment of skin photoaging.

Epithelial-specific loss of Smad4 alleviates the fibrotic response in an acute colitis mouse model.

Mucosal healing is associated with better clinical outcomes in patients with inflammatory bowel disease. But the epithelial-specific contribution to mucosal healing in vivo is poorly understood. We evaluated mucosal healing in an acute dextran sulfate sodium mouse model that shows an alleviated colitis response after epithelial-specific loss of Smad4. We find that enhanced epithelial wound healing alleviates the fibrotic response. Dextran sulfate sodium caused increased mesenchymal collagen deposition-indicative of fibrosis-within a week in the WT but not in the Smad4 KO colon. The fibrotic response correlated with decreased epithelial proliferation in the WT, whereas uninterrupted proliferation and an expanded zone of proliferation were observed in the Smad4 KO colon epithelium. Furthermore, the Smad4 KO colon showed epithelial extracellular matrix alterations that promote epithelial regeneration. Our data suggest that epithelium is a key determinant of the mucosal healing response in vivo, implicating mucosal healing as a strategy against fibrosis in inflammatory bowel disease patients.

A bovine model of hypoxia-induced pulmonary hypertension reveals a gradient of immune and matrisome response with a complement signature found in circulation.

Pulmonary hypertension (PH) is a progressive vascular disease characterized by vascular remodeling, stiffening, and luminal obstruction, driven by dysregulated cell proliferation, inflammation, and extracellular matrix (ECM) alterations. Despite the recognized contribution of ECM dysregulation to PH pathogenesis, the precise molecular alterations in the matrisome remain poorly understood. In this study, we employed a matrisome-focused proteomics approach to map the protein composition in a young bovine calf model of acute hypoxia-induced PH. Our findings reveal distinct alterations in the matrisome along the pulmonary vascular axis, with the most prominent changes observed in the main pulmonary artery. Key alterations included a strong immune response and wound repair signature, characterized by increased levels of complement components, coagulation cascade proteins, and provisional matrix markers. Additionally, we observed upregulation of ECM-modifying enzymes, growth factors, and core ECM proteins implicated in vascular stiffening, such as collagens, periostin, tenacsin-C, and fibrin(ogen). Notably, these alterations correlated with increased mean pulmonary arterial pressure and vascular remodeling. In the plasma, we identified increased levels of complement components, indicating a systemic inflammatory response accompanying the vascular remodeling. Our findings shed light on the dynamic matrisome remodeling in early-stage PH, implicating a wound-healing trajectory with distinct patterns from the MPA to the distal vasculature. This study provides novel insights into the molecular underpinnings of PH pathogenesis and highlights potential biomarkers and therapeutic targets within the matrisome landscape.

YAP1 and WWTR1 are required for murine pregnancy initiation.

Endometrial stromal cell decidualization is required for pregnancy success. Although this process is integral to fertility, many of the intricate molecular mechanisms contributing to decidualization remain undefined. One pathway that has been implicated in endometrial stromal cell decidualization in humans in vitro, is the Hippo signaling pathway. Two previously conducted studies showed that the effectors of the Hippo signaling pathway, YAP1 and WWTR1, are required for decidualization of primary endometrial stromal cells in vitro. To investigate the in vivo role of YAP1 and WWTR1 in decidualization and pregnancy initiation, we generated Progesterone receptor Cre mediated mutation of a combination of Yap1 and Wwtr1 alleles. Female Yap1 and Wwtr1 triple allele mutants exhibited subfertility, a compromised decidualization response, decreased endometrial receptivity, delayed embryonic development, and a unique transcriptional profile at 7.5 days post coitus. Bulk mRNA sequencing revealed aberrant maternal remodeling evidenced by significant alterations in extracellular matrix encoding genes at 7.5 days post-coitus in mutant dams and enrichment for terms associated with fertility-compromising diseases like pre-eclampsia and endometriosis. In addition, differentially expressed genes overlapped directionally with Estrogen receptor and Epidermal growth factor receptor regulated genes as identified by microarray. Our results indicate that Yap1 and Wwtr1 are necessary for successful mammalian pregnancy initiation.

Losartan-based nanocomposite hydrogel overcomes chemo-immunotherapy resistance by remodeling tumor mechanical microenvironment

Preclinical studies demonstrating high cure rates with PD1/PD-L1 combinations have led to numerous clinical trials, but emerging results are disappointing. These combined immunotherapies are commonly employed for patients with refractory tumors following prior treatment with cytotoxic agents. Here, we uncovered that the post-chemotherapy tumor presents a unique mechanical microenvironment characterized by an altered extracellular matrix (ECM) elasticity and increased stiffness, which facilitate the development of aggressive tumor phenotypes and confer resistance to checkpoint blocking therapy. As thus, we rationally designed an in situ nanocomposite hydrogel system, LOS&FeOX@Gel, which enabled effective and specific delivery of the therapeutic payloads (losartan [LOS] and oxaliplatin [OX]) into tumor. We demonstrate that sustained release of LOS effectively remodels the tumor mechanical microenvironment (TMM) by reducing ECM deposition and its associated “solid stress”, thereby augmenting the efficacy of OX and its immunological effects. Importantly, this hydrogel system greatly sensitized post-chemotherapy tumor to checkpoint blocking therapy, showing synergistic therapeutic effects against cancer metastasis. Our study provides mechanistic insights and preclinical rationale for modulating TMM as a potential neoadjuvant regimen for tumor to optimize the benefits of chemo-immunotherapy, which lays the groundwork for leveraging “mechanical-immunoengineering” strategies to combat refractory tumors.Graphical

Diseased Tendon Models Demonstrate Influence of Extracellular Matrix Alterations on Extracellular Vesicle Profile.

Tendons enable movement through their highly aligned extracellular matrix (ECM), predominantly composed of collagen I. Tendinopathies disrupt the structural integrity of tendons by causing fragmentation of collagen fibers, disorganization of fiber bundles, and an increase in glycosaminoglycans and microvasculature, thereby driving the apparent biomechanical and regenerative capacity in patients. Moreover, the complex cellular communication within the tendon microenvironment ultimately dictates the fate between healthy and diseased tendon, wherein extracellular vesicles (EVs) may facilitate the tendon's fate by transporting biomolecules within the tissue. In this study, we aimed to elucidate how the EV functionality is altered in the context of tendon microenvironments by using polycaprolactone (PCL) electrospun scaffolds mimicking healthy and pathological tendon matrices. Scaffolds were characterized for fiber alignment, mechanical properties, and cellular activity. EVs were isolated and analyzed for concentration, heterogeneity, and protein content. Our results show that our mimicked healthy tendon led to an increase in EV secretion and baseline metabolic activity over the mimicked diseased tendon, where reduced EV secretion and a significant increase in metabolic activity over 5 days were observed. These findings suggest that scaffold mechanics may influence EV functionality, offering insights into tendon homeostasis. Future research should further investigate how EV cargo affects the tendon's microenvironment.

Facial pore refining by targeting dermal and epidermal functions: Assessment across age and gender.

Conspicuous facial pores are benign but represent a cosmetic concern for men and women. Recent works described dermal and epidermal impairments as clinical causes of enlarged pores. Morphological modifications of skin at the site of pores were associated with collagen density loss, possible alteration of extracellular matrix and abnormal differentiation of keratinocytes. A composition containing mannose-6-phosphate (Active Complex) was designed to address these different aspects of pore enlargement. Invitro and exvivo evaluations were conducted in different models mimicking disturbance of dermal and epidermal functions. The pore refining activity of Active Complex was assessed in two clinical trials studying a Caucasian women cohort and an Asian men cohort. At the dermal level, Active Complex upregulated collagen I and decorin synthesis, and genes encoding collagens I, III, V, VII, XVII; suggesting its ability to favor collagen fiber organization and anchorage. The downregulation of matrix metalloprotease, involved in extracellular matrix degradation, reinforced the protective effect of Active Complex in the dermis. Active Complex down modulated differentiation markers in keratinocytes as well as genes involved in cell renewal. Study of reconstructed human epidermis modeling keratinocyte hyperproliferation revealed that Active Complex mitigated two markers of this state: number of nuclei in the stratum corneum and involucrin expression. Clinical trials confirmed the pore refining activity of Active Complex on men and women of different ages and ethnicities; -24% total skin pore area after 56 days of application on women, and -30.2% on men after 7 days. This work demonstrates the interest to target dermal and epidermal modifications described in conspicuous pore area, especially dermis fiber organization, to address this cosmetic concern.

Endothelial YAP/TAZ activation promotes atherosclerosis in a mouse model of Hutchinson-Gilford progeria syndrome.

Hutchinson-Gilford progeria syndrome (HGPS) is an extremely rare disease caused by the expression of progerin, an aberrant protein produced by a point mutation in the LMNA gene. HGPS patients show accelerated aging and die prematurely mainly from complications of atherosclerosis such as myocardial infarction, heart failure, or stroke. However, the mechanisms underlying HGPS vascular pathology remain ill-defined. We used single-cell RNA sequencing to characterize the aorta in progerin-expressing LmnaG609G/G609G mice and wild-type controls, with a special focus on endothelial cells (ECs). HGPS ECs showed gene expression changes associated with extracellular matrix alterations, increased leukocyte extravasation, and activation of the yes-associated protein 1/transcriptional activator with PDZ-binding domain (YAP/TAZ) mechanosensing pathway, all validated by different techniques. Atomic force microscopy experiments demonstrated stiffer subendothelial extracellular matrix in progeroid aortae, and ultrasound assessment of live HGPS mice revealed disturbed aortic blood flow, both key inducers of the YAP/TAZ pathway in ECs. YAP/TAZ inhibition with verteporfin reduced leukocyte accumulation in the aortic intimal layer and decreased atherosclerosis burden in progeroid mice. Our findings identify endothelial YAP/TAZ signaling as a key mechanism of HGPS vascular disease and open a new avenue for the development of YAP/TAZ-targeting drugs to ameliorate progerin-induced atherosclerosis.

Obesity-driven changes in breast tissue exhibit a pro-angiogenic extracellular matrix signature

Obesity has reached epidemic proportions in the United States, emerging as a risk factor for the onset of breast cancer and a harbinger of unfavorable outcomes [1–3]. Despite limited understanding of the precise mechanisms, both obesity and breast cancer are associated with extracellular matrix (ECM) rewiring [4–6]. Utilizing total breast tissue proteomics, we analyzed normal-weight (18.5 to < 25 kg/m2), overweight (25 to < 30 kg/m2), and obese (≥30 kg/m2) individuals to identify potential ECM modifying proteins for cancer development and acceleration. Obese individuals exhibited substantial ECM alterations, marked by increased basement membrane deposition, angiogenic signatures, and ECM-modifying proteins. Notably, the collagen IV crosslinking enzyme peroxidasin (PXDN) emerged as a potential mediator of the ECM changes in individuals with an elevated body mass index (BMI), strongly correlating with angiogenic and basement membrane signatures. Furthermore, glycan-binding proteins galectin-1 (LGALS1) and galectin-3 (LGALS3), which play crucial roles in matrix interactions and angiogenesis, also strongly correlate with ECM modifications. In breast cancer, elevated PXDN, LGALS1, and LGALS3 correlate with reduced relapse-free and distant-metastatic-free survival. These proteins were significantly associated with mesenchymal stromal cell markers, indicating adipocytes and fibroblasts may be the primary contributors of the obesity-related ECM changes. Our findings unveil a pro-angiogenic ECM signature in obese breast tissue, offering potential targets to inhibit breast cancer development and progression.

A 3D Epithelial-Mesenchymal Co-Culture Model of the Airway Wall Using Native Lung Extracellular Matrix.

Chronic obstructive pulmonary disease (COPD) is a chronic lung disease characterized by ongoing inflammation, impaired tissue repair, and aberrant interplay between airway epithelium and fibroblasts, resulting in an altered extracellular matrix (ECM) composition. The ECM is the three-dimensional (3D) scaffold that provides mechanical support and biochemical signals to cells, now recognized not only as a consequence but as a potential driver of disease progression. To elucidate how the ECM influences pathophysiological changes occurring in COPD, in vitro models are needed that incorporate the ECM. ECM hydrogels are a novel experimental tool for incorporating the ECM in experimental setups. We developed an airway wall model by combining lung-derived ECM hydrogels with a co-culture of primary human fibroblasts and epithelial cells at an air-liquid interface. Collagen IV and a mixture of collagen I, fibronectin, and bovine serum albumin were used as basement membrane-mimicking coatings. The model was initially assembled using porcine lung-derived ECM hydrogels and subsequently with COPD and non-COPD human lung-derived ECM hydrogels. The resulting 3D construct exhibited considerable contraction and supported co-culture, resulting in a differentiated epithelial layer. This multi-component 3D model allows the investigation of remodelling mechanisms, exploring ECM involvement in cellular crosstalk, and holds promise as a model for drug discovery studies exploring ECM involvement in cellular interactions.

Proteomic insights into extracellular matrix dynamics in the intestine of Labeo rohita during Aeromonas hydrophila infection.

The study underscores the critical role of the extracellular matrix (ECM) and its associated proteins in the immune response of aquatic organisms during bacterial infections like Aeromonas hydrophila. Understanding the intricate interplay between ECM alterations and immune response pathways provides crucial insights for developing effective disease control strategies in aquaculture. By identifying key proteins and pathways involved in host defense mechanisms, this research lays the groundwork for targeted interventions to mitigate the impact of bacterial infections on fish health and aquaculture production.

High hydrostatic pressure treatment for advanced tissue grafts in reconstructive head and neck surgery.

The increasing importance of regenerative medicine has resulted in a growing need for advanced tissue replacement materials in head and neck surgery. Allo- and xenogenic graft processing is often time-consuming and can deteriorate the extracellular matrix (ECM). High hydrostatic pressure (HHP)-treatment could allow specific devitalization while retaining the essential properties of the ECM. Porcine connective tissue and cartilage were HHP-treated at 100-400 MPa for 10 min. Structural modifications following HHP-exposure were examined using electron microscopy, while devitalization was assessed through metabolism and cell death analyses. Furthermore, ECM alterations and decellularization were evaluated by histology, biomechanical testing, and DNA content analysis. Additionally, the inflammatory potential of HHP-treated tissue was evaluated in vivo using a dorsal skinfold chamber in a mouse model. The devitalization effects of HHP were dose-dependent, with a threshold identified at 200 MPa for fibroblasts and chondrocytes. At this pressure level, HHP induced structural alterations in cells, with a shift toward late-stage apoptosis. HHP-treatment preserved ECM structure and biomechanical properties, but did not remove cell debris from the tissue. This study observed a pressure-dependent increase of markers suggesting the occurrence of immunogenic cell death. In vivo investigations revealed an absence of inflammatory responses to HHP-treated tissue, indicating a favorable biological response to HHP. In conclusion, application of HHP devitalizes fibroblasts and chondrocytes at 200 MPa while retaining the essential properties of the ECM. Prospectively, HHP may simplify the preparation of allo- and xenogenic tissue replacement materials and increase the availability of grafts in head and neck surgery.

Effect of Human Platelet-Rich Fibrin Lysate on Collagen Type I, Collagen Type III, and Matrix Metalloproteinase 1 : A Protocol Study on Rat Models with Pelvic Organ Prolapse

Background Pelvic organ prolapse (POP) is a prevalent condition caused by weakened pelvic floor support structures. Extracellular matrix alterations, including changes in collagen type I, collagen type III, and matrix metalloproteinase 1 (MMP-1), contribute to the pathogenesis of this condition. Human platelet-rich fibrin lysate (hPRF-L) is a novel regenerative treatment that has shown beneficial results in treating structural weaknesses related to various pelvic floor diseases, including POP. Methods This study protocol aims to investigate the effects of hPRF-L injection on collagen I, III, and MMP-1 in the vaginal mucosa of a rat POP model. POP will be induced in female Sprague-Dawley rats, which will be randomly assigned to control, sham, and hPRF-L treatment groups. The hPRF-L group will receive weekly injections of hPRF-L (25, 50, or 75 μL) into the vaginal mucosa for 4 weeks. Vaginal tissue samples will be collected, and collagen type I, collagen type III, and MMP-1 expression will be evaluated using quantitative reverse transcription polymerase chain reaction and immunohistochemical analyses. Data analysis will be performed with ANOVA and post-hoc tests. Discussion The findings from this study protocol are expected to provide valuable insights into the mechanisms by which hPRF-L impacts the structural integrity of the pelvic floor. By elucidating these mechanisms, this study aims to inform future POP treatment strategies. The anticipated results are an increase in collagen type I and III expression and a reduction in MMP-1 levels in the hPRF-L treatment group compared to the control and sham groups. These outcomes could support the use of hPRF-L as a regenerative therapy for managing POP, offering a potential alternative to more invasive surgical interventions. Conclusion The expected results will contribute to the development of less invasive treatments for POP, improving patient outcomes and quality of life.

Protein kinase N promotes cardiac fibrosis in heart failure by fibroblast-to-myofibroblast conversion

Chronic fibrotic tissue disrupts various organ functions. Despite significant advances in therapies, mortality and morbidity due to heart failure remain high, resulting in poor quality of life. Beyond the cardiomyocyte-centric view of heart failure, it is now accepted that alterations in the interstitial extracellular matrix (ECM) also play a major role in the development of heart failure. Here, we show that protein kinase N (PKN) is expressed in cardiac fibroblasts. Furthermore, PKN mediates the conversion of fibroblasts into myofibroblasts, which plays a central role in secreting large amounts of ECM proteins via p38 phosphorylation signaling. Fibroblast-specific deletion of PKN led to a reduction of myocardial fibrotic changes and cardiac dysfunction in mice models of ischemia-reperfusion or heart failure with preserved ejection fraction. Our results indicate that PKN is a therapeutic target for cardiac fibrosis in heart failure.

ECM Microenvironment in Vascular Homeostasis: New Targets for Atherosclerosis.

Alterations in vascular extracellular matrix (ECM) components, interactions, and mechanical properties influence both the formation and stability of atherosclerotic plaques. This review discusses the contribution of the ECM microenvironment in vascular homeostasis and remodeling in atherosclerosis, highlighting Cartilage oligomeric matrix protein (COMP) and its degrading enzyme ADAMTS7 as examples, and proposes potential avenues for future research aimed at identifying novel therapeutic targets for atherosclerosis based on the ECM microenvironment.

Exploiting a tumor softening targeted bomb for mechanical gene therapy of chemoresistant Triple-Negative breast cancer

Triple-negative breast cancer (TNBC)-the most aggressive and refractory subtype of breast cancer-plagues many patients. The tumor physical microenvironment (TPME) is characterized by altered stromal composition and extracellular matrix (ECM), which may contribute to tissue stiffness and compromise therapeutic efficacy. Here, based on clinical data analysis and preclinical model validation, we discover that chemoresistant TNBC tends to have a stiffer TPME with a more aggressive genomic landscape, in which lysyl oxidase (LOX) exerts pivotal effects. Anlotinib (An), a multi-targeted tyrosine kinase inhibitor, has great promising potential in the treatment of TNBC. In this regard, we developed a tumor-softening nanobomb (An&siLOX@NPs) that remodels TPME by co-delivering small interfering siRNAs silencing LOX and the anti-angiogenic drug, anlotinib (An). The improved cytosolic delivery of siLOX enables TPME remodeling via reducing deposition and cross-linking between collagen and fibronectin, thereby promoting enrichment of An to improve its therapeutic outcomes. In chemoresistant TNBC, we confirm the An&siLOX@NPs nanobomb-mediated mechanical gene therapy results in obvious inhibition of local tumor outgrowth and prolongs survival. Additionally, softened TPME reactivates intratumoral immune milieu to bolster sensitivity to anti-PD-L1 immunotherapy, completely curing 33.3% of the metastatic tumors, further generating a synergistic anti-tumor efficacy. Collectively, our mechanical gene therapy strategy represents a highly efficient, safe, and versatile anti-drug resistance modality, which not only can solve the snag problem of TNBC treatment but also provides a new demonstration for other tumor treatments.

The LAMB3-EGFR signaling pathway mediates synergistic Anti-Cancer effects of berberine and emodin in Pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy, primarily due to the intrinsic development of chemoresistance. The most apparent histopathological feature associated with chemoresistance is the alterations in extracellular matrix (ECM) proteins. Natural dietary botanicals such as berberine (BBR) and emodin (EMO) have been shown to possess chemo-preventive potential by regulating ECM in various cancers. Herein, we further investigated the potential synergistic effects of BBR and EMO in enhancing anticancer efficacy by targeting ECM proteins in pancreatic cancer. Genomewide transcriptomic profiling identified that LAMB3 was significantly upregulated in PDAC tissue and highly associated with poor overall survival (OS, hazard ratio [HR], 2.99, 95 % confidence interval [CI], 1.46–6.15; p = 0.003) and progress-free survival (PFS, HR, 2.59; 95 % CI, 1.30–5.18; p = 0.007) in PDAC. A systematic series of functional experiments in BxPC-3 and MIA-PaCa-2 cells revealed that the combination of BBR and EMO exhibited synergistic anti-tumor potential, as demonstrated by cell proliferation, clonogenicity, migration, and invasion assays (p < 0.05–0.001). The combination also altered the expression of key proteins involved in apoptosis, EMT, and EGFR/ERK1,2/AKT signaling. These findings were further supported by patient-derived organoids (PDOs), where the combined treatment resulted in fewer and smaller organoids compared to each compound individually (p < 0.05–0.001). Our results suggest that BBR combined with EMO exerts synergistic anti-cancer effects by modulating the EGFR-signaling pathway through interference with LAMB3 in PDAC.

The Impact of Sciatic Nerve Injury on Extracellular Matrix of Lower Limb Muscle and Thoracolumbar Fascia: An Observational Study.

Peripheral nerve injury (PNI) is a complex clinical challenge resulting in functional disability. Neurological recovery does not always ensure functional recovery, as extracellular matrix (ECM) alterations affect muscle function. This study evaluates hyaluronan (HA) and collagen concentration in the gastrocnemius muscle and thoracolumbar fascia (TLF) in unilateral lower limb PNI rats to explore systemic ECM alterations following PNI and their impacts on functional recovery. Eighteen 8-week-old male Sprague-Dawley rats were divided into experimental (n = 12 left sciatic nerve injury) and control (n = 6) groups. After six weeks, motor function was evaluated. Muscle and TLF samples were analysed for HA and collagen distribution and concentrations. SFI and gait analysis confirmed a functional deficit in PNI rats 6 weeks after surgery. HA concentration in both sides of the muscles decreased by approximately one-third; both sides showed significantly higher collagen concentration than healthy rats (12.74 ± 4.83 µg/g), with the left (32.92 ± 11.34 µg/g) significantly higher than the right (20.15 ± 7.03 µg/g). PNI rats also showed significantly lower HA (left: 66.95 ± 20.08 µg/g; right: 112.66 ± 30.53 µg/g) and higher collagen (left: 115.89 ± 28.18 µg/g; right: 90.43 ± 20.83 µg/g) concentrations in both TLF samples compared to healthy rats (HA: 167.18 ± 31.13 µg/g; collagen: 47.51 ± 7.82 µg/g), with the left TLF more affected. Unilateral lower limb PNI induced HA reduction and collagen accumulation in both the lower limb muscles and the TLF, potentially exacerbating motor function impairment and increasing the risk of low back dysfunctions.

Exploring the Potential of Saphenous Vein Grafts Ex Vivo: A Model for Intimal Hyperplasia and Re-Endothelialization.

Coronary artery bypass grafting (CABG) utilizing saphenous vein grafts (SVGs) stands as a fundamental approach to surgically treating coronary artery disease. However, the long-term success of CABG is often compromised by the development of intimal hyperplasia (IH) and subsequent graft failure. Understanding the mechanisms underlying this pathophysiology is crucial for improving graft patency and patient outcomes. Objectives: This study aims to explore the potential of an ex vivo model utilizing SVG to investigate IH and re-endothelialization. Methods: A thorough histological examination of 15 surplus SVG procured from CABG procedures at Hospital Canselor Tuanku Muhriz, Malaysia, was conducted to establish their baseline characteristics. Results: SVGs exhibited a mean diameter of 2.65 ± 0.93 mm with pre-existing IH averaging 0.42 ± 0.13 mm in thickness, alongside an observable lack of luminal endothelial cell lining. Analysis of extracellular matrix components, including collagen, elastin, and glycosaminoglycans, at baseline and after 7 days of ex vivo culture revealed no significant changes in collagen but demonstrated increased percentages of elastin and glycosaminoglycans. Despite unsuccessful attempts at re-endothelialization with blood outgrowth endothelial cells, the established ex vivo SVG IH model underscores the multifaceted nature of graft functionality and patency, characterized by IH presence, endothelial impairment, and extracellular matrix alterations post-CABG. Conclusions: The optimized ex vivo IH model provides a valuable platform for delving into the underlying mechanisms of IH formation and re-endothelialization of SVG. Further refinements are warranted, yet this model holds promise for future research aimed at enhancing graft durability and outcomes for CAD patients undergoing CABG.