scholarly journals 14 Characterization of adipose tissue extracellular matrix component mRNA expression during porcine adipogenesis using real-time PCR

2020 ◽  
Vol 98 (Supplement_2) ◽  
pp. 35-35
Author(s):  
Maegan A Reeves ◽  
Courtney E Charlton ◽  
Terry D Brandebourg
Keyword(s):  
Extracellular Matrix ◽  
Adipose Tissue ◽  
Mrna Expression ◽  
Real Time ◽  
Real Time Pcr ◽  
Collagen Type ◽  
Primary Cultures ◽  
Collagen Type I ◽  
Type I ◽  
Matrix Metallopeptidase

Abstract Given adipose tissue is histologically classified as connective tissue, we hypothesized expression of extracellular matrix (ECM) components are significantly altered during adipogenesis. However, little is known about the regulation of the ECM during adipose tissue development in the pig. Therefore, the objective of this study was to characterize expression of ECM components during porcine adipogenesis. Primary cultures of adipose tissue stromal-vascular cells were harvested from 3-day-old neonatal pigs (n=6) and preadipocytes induced to differentiate in vitro for 8 days in the presence of insulin, hydrocortisone, and rosiglitazone. Total RNA was extracted from these cultures on days 0 and 8 post-induction. Real-time PCR was then utilized to determine changes in mRNA expression for collagen type I alpha 1 chain (COL1A), collagen type I alpha 2 chain (COL2A), collagen type I alpha 3 chain (COL3A), collagen type I alpha 4 chain (COL4A), collagen type I alpha 6 chain (COL6A), biglycan, fibronectin, laminin, nitogen-1 (NID1), matrix metallopeptidase 2 (MMP2), matrix metallopeptidase 9 (MMP9), metallopeptidase inhibitor 3 (TIMP3). The mRNA abundances of COL1A, COL3A and MMP2 were significantly downregulated 2.86-fold (P < 0.05), 16.7-fold (P < 0.01) and 3.1-fold (P < 0.05) respectively in day 8 (differentiated) compared to day 0 (undifferentiated) cultures. Meanwhile, mRNA abundances were significantly upregulated during adipogenesis for the COL2A (2.82-fold; P < 0.05), COL4A (2.01-fold; P < 0.05), COL6A (2.8-fold; P < 0.05), biglycan (49.9- fold; P < 0.001), fibronectin (452-fold; P < 0.001), laminin (6.1-fold; P < 0.05), NID1(47.4-fold; P < 0.01), MMP9 (76.8- fold; P < 0.01), and TIMP3(3.04-fold; P < 0.05) genes. These data support the hypothesis that significant changes in ECM components occur during porcine adipogenesis. Modulating adipose tissue ECM remodeling might be a novel strategy to manipulate adiposity in the pig.

scholarly journals The effects of Neuroblastoma Breakpoint Family Members 1 and 15 variant on osteogenesis in patients with orbital hypertelorism

2019 ◽  
Author(s):  
Gang CHAI ◽  
Nan HUANG ◽  
Qun ZHANG ◽  
Tianya Li ◽  
Wei Chen ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Family Member ◽  
Real Time ◽  
Real Time Pcr ◽  
Collagen Type ◽  
Gene Sequencing ◽  
Collagen Type I ◽  
Type I ◽  
Alizarin Red ◽  
Related Transcription Factor

Abstract Background: The purpose of this study was to examine the effects of Neuroblastoma Breakpoint Family, Member 1, (NBPF1) and Neuroblastoma Breakpoint Family, Member 15, (NBPF15) on osteogenesis in patients with orbital hypertelorism. Methods: The genetic information of three patients with orbital hypertelorism was analyzed via gene sequencing. We used real-time PCR to determine osteogenic correlation indices and performed osteogenic correlation staining to examine the function of NBPF1 and NBPF15 in the state of silence and overexpression. Results: NBPF1 and NBPF15 gene variants were observed in patients with orbital hypertelorism. During osteogenesis, when NBPF1 and NBPF15 were overexpressed, real-time PCR showed that expression of the osteogenesis-related indicators alkaline phosphatase (ALP), runt-related transcription factor 2, osteopontin, and collagen type I alpha 1 chain increased; Alizarin Red and ALP staining showed that overexpression of both genes promoted osteogenesis. When NBPF1 and NBPF15 were silenced, expression of ALP, runt-related transcription factor 2, osteopontin, and collagen type I alpha 1 chain decreased as observed during real-time PCR, and the inhibition of osteogenesis was demonstrated by Alizarin Red and ALP staining. Conclusion: NBPF1 and NBPF15 variants existed in patients with orbital hypertelorism and they promoted osteogenesis.

scholarly journals The Effect of Intra-articular Injection of MicroRNA-210 on Ligament Healing in a Rat Model

2012 ◽  
Vol 40 (11) ◽  
pp. 2470-2478 ◽  
Author(s):  
Takeshi Shoji ◽  
Tomoyuki Nakasa ◽  
Keiichiro Yamasaki ◽  
Akira Kodama ◽  
Shigeru Miyaki ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Collagen Type ◽  
Acl Injury ◽  
Collagen Type I ◽  
Pcr Analysis ◽  
Control Group ◽  
Type I ◽  
Ligament Healing ◽  
Isolectin B4

Background: It is known from clinical and experimental studies that the healing potential of the anterior cruciate ligament (ACL) is extremely poor and that early phases of ligament healing require an augmented blood supply. MicroRNA (miRNA) is a type of small, noncoding RNA that negatively regulates gene expression, and miRNA (miR)-210 is reported to be crucial for cell response to hypoxia, vascular endothelial growth factor (VEGF)–driven endothelial cell migration, and formation of capillary-like structures. Purpose: The purpose of this study was to examine the effect of intra-articular injection of miRNA miR-210 on acceleration of ACL healing. Study Design: Controlled laboratory study. Methods: Two experiments were performed in this study. The ACLs of 12-week-old male LEW/CrlCrlj rats were partially transected. First, the temporal expression change of miR-210 after ACL injury was analyzed using real-time polymerase chain reaction (PCR) on day zero, and 1, 2, and 4 weeks after injury (n = 5 at each time point). Next, intra-articular injection of double-stranded (ds) miR-210 with atelocollagen was performed soon after injury. The control group was injected with control small interfering RNA (siRNA). Four weeks after injection, biomechanical and histological assessments of samples stained with H&E as well as Masson trichrome, and immunohistochemistry for VEGF, fibroblast growth factor 2 (FGF2), isolectin B4, and collagen type I, were performed. Real-time PCR analysis was also performed for quantitative evaluation of miR-210, VEGF-A, and collagen type I. Results: Real-time PCR analysis revealed that miR-210 expression was decreased soon after injury but gradually increased thereafter. Histological analysis confirmed that the transected area was covered with healing tissue in the miR-210 group but remained devoid of any tissue in the control group 4 weeks after injury. Biomechanical analysis confirmed the improvement of biomechanical properties in the miR-210 group; the ultimate failure loads 4 weeks after injection were 30.5 ± 3.1 N in the miR-210 group and 22.8 ± 3.1 N in the control group ( P < .05). Real-time PCR analysis showed that endogenous miR-210, VEGF, and collagen type I were highly expressed compared with controls, and immunohistochemistry for VEGF, FGF2, isolectin B4, and collagen type I showed that VEGF and FGF2 were highly upregulated, and there were abundant blood vessels and fibrotic deposition in the miR-210 group. Conclusion: Injection of ds miR-210 was effective in promoting the healing of partially torn ACLs through enhancement of angiogenesis via upregulation of VEGF and FGF2. Clinical Relevance: It might represent a potential therapeutic approach for treatment of ACL injury.

scholarly journals Precision-Cut Kidney Slices as a Tool to Understand the Dynamics of Extracellular Matrix Remodeling in Renal Fibrosis

2016 ◽  
Vol 11 ◽  
pp. BMI.S38439 ◽  
Author(s):  
Federica Genovese ◽  
Zsolt S. Kàrpàti ◽  
Signe H. Nielsen ◽  
Morten A. Karsdal
Keyword(s):  
Extracellular Matrix ◽  
Collagen Type ◽  
Interstitial Fibrosis ◽  
Ex Vivo ◽  
Collagen Type I ◽  
Extracellular Matrix Remodeling ◽  
Type I ◽  
Matrix Remodeling ◽  
Renal Interstitial Fibrosis ◽  
Ex Vivo Model

The aim of this study was to set up an ex vivo model for renal interstitial fibrosis in order to investigate the extracellular matrix (ECM) turnover profile in the fibrotic kidney. We induced kidney fibrosis in fourteen 12-week-old male Sprague Dawley rats by unilateral ureteral obstruction (UUO) surgery of the right ureter. The left kidney (contralateral) was used as internal control. Six rats were sham operated and used as the control group. Rats were terminated two weeks after the surgery; the kidneys were excised and precision-cut kidney slices (PCKSs) were cultured for five days in serum-free medium. Markers of collagen type I formation (P1NP), collagen type I and III degradation (C1M and C3M), and α-smooth muscle actin (αSMA) were measured in the PCKS supernatants by enzyme-linked immunosorbent assay. P1NP, C1M, C3M, and α-SMA were increased up to 2- to 13-fold in supernatants of tissue slices from the UUO-ligated kidneys compared with the contralateral kidneys ( P < 0.001) and with the kidneys of sham-operated animals ( P < 0.0001). The markers could also reflect the level of fibrosis in different animals. The UUO PCKS ex vivo model provides a valuable translational tool for investigating the extracellular matrix remodeling associated with renal interstitial fibrosis.

Mesenchymal stem cells from adipose tissue which have been differentiated into chondrocytes in three-dimensional culture express lubricin

2011 ◽  
Vol 236 (11) ◽  
pp. 1333-1341 ◽  
Author(s):  
Giuseppe Musumeci ◽  
Debora Lo Furno ◽  
Carla Loreto ◽  
Rosario Giuffrida ◽  
Silvia Caggia ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Adipose Tissue ◽  
Collagen Type ◽  
Three Dimensional ◽  
3D Culture ◽  
Collagen Type I ◽  
Type I ◽  
Human Mscs ◽  
Alternative Source

The present study focused on the isolation, cultivation and characterization of human mesenchymal stem cells (MSCs) from adipose tissue and on their differentiation into chondrocytes through the NH ChondroDiff medium. The main aim was to investigate some markers of biomechanical quality of cartilage, such as lubricin, and collagen type I and II. Little is known, in fact, about the ability of chondrocytes from human MSCs of adipose tissue to generate lubricin in three-dimensional (3D) culture. Lubricin, a 227.5-kDa mucinous glycoprotein, is known to play an important role in articular joint physiology, and the loss of accumulation of lubricin is thought to play a role in the pathology of osteoarthritis. Adipose tissue is an alternative source for the isolation of multipotent MSCs, which allows them to be obtained by a less invasive method and in larger quantities than from other sources. These cells can be isolated from cosmetic liposuctions in large numbers and easily grown under standard tissue culture conditions. 3D chondrocytes were assessed by histology (hematoxylin and eosin) and histochemistry (Alcian blue and Safranin-O/fast green staining). Collagen type I, II and lubricin expression was determined through immunohistochemistry and Western blot. The results showed that, compared with control cartilage and monolayer chondrocytes showing just collagen type I, chondrocytes from MSCs (CD44-, CD90- and CD105- positive; CD45-, CD14- and CD34-negative) of adipose tissue grown in nodules were able to express lubricin, and collagen type I and II, indicative of hyaline cartilage formation. Based on the function of lubricin in the joint cavity and disease and as a potential therapeutic agent, our results suggest that MSCs from adipose tissue are a promising cell source for tissue engineering of cartilage. Our results suggest that chondrocyte nodules producing lubricin could be a novel biotherapeutic approach for the treatment of cartilage abnormalities.

P0672CALPAINS 1 AND 2 ARE INCREASED DURING THE DEVELOPMENT OF CHRONIC KIDNEY DAMAGE IN MICE FED WITH AN ADENINE RICH DIET

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Elena Gutiérrez-Calabrés ◽  
Sofía Campillo de Blas ◽  
Lourdes Bohorquez Magro ◽  
Mercedes Griera-Merino ◽  
Diego García Ayuso ◽  
...  
Keyword(s):  
Renal Function ◽  
Mrna Expression ◽  
Protein Content ◽  
Experimental Model ◽  
Collagen Type ◽  
Critical Role ◽  
Cysteine Proteases ◽  
Collagen Type I ◽  
Standard Diet ◽  
Type I

Abstract Background and Aims Calpains are intracellular cysteine proteases that play a critical role in cell remodeling, being involved in multiple biological processes linked to tissue damage and repair mechanisms. In addition, they are released into the circulation, being able to carry out systemic actions with pathological consequences. The aim of this study was to investigate the role of calpains in the progression of chronic kidney disease (CKD) in an experimental model of chronic renal damage induced by adenine. Method We induced an experimental model of CKD, in mice fed for 2 weeks with an adenine-supplemented diet (0.2% adenine) (A). Animals receiving this diet develop a tubulointerstitial damage resembling that is observed in human CKD. Mice with standard diet were used as controls (C). Renal function was assessed by measuring serum blood urea nitrogen (BUN) and creatinine (mg/dl). Fibrosis markers (collagen type I and fibronectin) were determined by RT-qPCR. Changes in the renal content of calpains 1 and 2 were analyzed by western blot (protein content), and RT-qPCR (mRNA expression). Results Our results show functional and structural changes at renal level in the adenine-fed mice, with increased BUN (A: 72 mg/dl, C: 28 mg/dl, p &lt; 0.05), creatinine (A: 0.58 mg/dl, C: 0.25 mg/dl, p &lt; 0.05), collagen type I mRNA expression (A: 12.9 units, C: 1.2 units, p &lt; 0.05) and fibronectin mRNA expression (A: 3.46 units, C: 1.3 units, p &lt; 0.05). Furthermore, protein content of calpains 1 (A: 1.27 units, C: 0.78 units, p &lt; 0.05) and 2 (A: 1.30 units, C: 0.66 units, p &lt; 0.05) was significantly higher in adenine-fed mice when compared to control. At the same time, we observed a significant increase in gene expression of both calpain 1 (A: 4.21 units, C: 0.51 units, p &lt; 0.05) and 2 (A: 4.93 units, C: 0.56 units, p &lt; 0.05) in the adenine model regarding to mice with standard diet. Our results demonstrate that calpain 1 and 2 expression in renal tissue increases as CKD progresses. Interestingly, we found statistically significant correlations between renal calpains 1 and 2 protein and mRNA content and plasma BUN and creatinine (p &lt; 0.05, r between 0.79 and 0.92), as well as protein expression of calpain 2 and mRNA expression of collagen type I (p &lt; 0.05, r = 0.76). These data suggest a potential direct relationship between renal calpain 1 and 2 content and loss of renal function, in part due probably to the modulation of the fibrotic changes, in adenine fed mice. Conclusion We suggest an implication of calpains 1 and 2 in the development of CKD. Thus, effective calpain blockade or downregulation could be useful as a therapeutic strategy to prevent CKD. Further experiments will be necessary to establish the relationship between these factors.

Losartan attenuates paraquat-induced pulmonary fibrosis in rats

2014 ◽  
Vol 34 (5) ◽  
pp. 497-505 ◽  
Author(s):  
F Guo ◽  
YB Sun ◽  
L Su ◽  
S Li ◽  
ZF Liu ◽  
...  
Keyword(s):  
Pulmonary Fibrosis ◽  
Lung Injury ◽  
Mrna Expression ◽  
Collagen Type ◽  
Collagen Type I ◽  
Control Group ◽  
Type I ◽  
Expression Levels ◽  
Relative Expression ◽  
Tgf Β1

Paraquat (PQ) is one of the most widely used herbicides in the world and can cause pulmonary fibrosis in the cases with intoxication. Losartan, an angiotensin II type 1 receptor antagonist, has beneficial effects on the treatment of fibrosis. The aim of this study was to examine the effect of losartan on pulmonary fibrosis in PQ-intoxicated rats. Adult male Sprague Dawley rats ( n = 32, 180–220 g) were randomly assigned to four groups: (i) control group; (ii) PQ group; (iii) PQ + losartan 7d group; and (iv) PQ + losartan 14d group. Losartan treatment (intragastrically (i.g.), 10 mg/kg) was performed for 7 and 14 days after a single i.g. dose of 40 mg/kg PQ. All rats were killed on the 16th day, and hematoxylin–eosin and Masson’s trichrome staining were used to examine lung injury and fibrosis. The levels of hydroxyproline and transforming growth factor β1 (TGF-β1), matrix metallopeptidase 9 (Mmp9), and tissue inhibitor of metalloproteinase 1 (TIMP-1) messenger RNA (mRNA) expression and relative expression levels of collagen type I and III were also detected. PQ caused a significant increase in hydroxyproline content, mRNA expression of TGF-β1, Mmp9, and TIMP-1, and relative expression levels of collagen type I and III (  p < 0.05), while losartan significantly decreased the amount of hydroxyproline and downregulated TGF-β1, Mmp9, and TIMP-1 mRNA and collagen type I and III expressions (  p < 0.05). Histological examination of PQ-treated rats showed lung injury and widespread inflammatory cell infiltration in the alveolar space and pulmonary fibrosis, while losartan could markedly reduce such damage and prevent pulmonary fibrosis. The results of this study indicated that losartan could reduce lung damage and prevent pulmonary fibrosis induced by PQ.

Changes in extracellular matrix composition regulate cyclooxygenase-2 expression in human mesangial cells

2011 ◽  
Vol 300 (4) ◽  
pp. C907-C918 ◽  
Author(s):  
Matilde Alique ◽  
Laura Calleros ◽  
Alicia Luengo ◽  
Mercedes Griera ◽  
Miguel Ángel Iñiguez ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Collagen Type ◽  
Mesangial Cells ◽  
Collagen Type I ◽  
Collagen I ◽  
Type I ◽  
Camp Response Element ◽  
Response Element ◽  
Human Mesangial Cells ◽  
Cox 2

Glomerular diseases are characterized by a sustained synthesis and accumulation of abnormal extracellular matrix proteins, such as collagen type I. The extracellular matrix transmits information to cells through interactions with membrane components, which directly activate many intracellular signaling events. Moreover, accumulating evidence suggests that eicosanoids derived from cyclooxygenase (COX)-2 participate in a number of pathological processes in immune-mediated renal diseases, and it is known that protein kinase B (AKT) may act through different transcription factors in the regulation of the COX-2 promoter. The present results show that progressive accumulation of collagen I in the extracellular medium induces a significant increase of COX-2 expression in human mesangial cells, resulting in an enhancement in PGE2 production. COX-2 overexpression is due to increased COX-2 mRNA levels. The study of the mechanism implicated in COX-2 upregulation by collagen I showed focal adhesion kinase (FAK) activation. Furthermore, we observed that the activation of the phosphatidylinositol 3-kinase (PI3K)/AKT pathway by collagen I and collagen I-induced COX-2 overexpression was abolished by PI3K and AKT inhibitors. Additionally, we showed that the cAMP response element (CRE) transcription factor is implicated. Finally, we studied COX-2 expression in an animal model, NG-nitro-l-arginine methyl ester hypertensive rats. In renal tissue and vascular walls, COX-2 and collagen type I content were upregulated. In summary, our results provide evidence that collagen type I increases COX-2 expression via the FAK/PI3K/AKT/cAMP response element binding protein signaling pathway.

scholarly journals Effect of acute resistance exercise and sex on human patellar tendon structural and regulatory mRNA expression

2009 ◽  
Vol 106 (2) ◽  
pp. 468-475 ◽  
Author(s):  
Bridget E. Sullivan ◽  
Chad C. Carroll ◽  
Bozena Jemiolo ◽  
Scott W. Trappe ◽  
S. Peter Magnusson ◽  
...  
Keyword(s):  
Resistance Exercise ◽  
Mrna Expression ◽  
Patellar Tendon ◽  
Type I Collagen ◽  
Collagen Type ◽  
Collagen Type I ◽  
Tissue Inhibitors Of Metalloproteinases ◽  
Type I ◽  
Collagen Type Iii ◽  
Type Iii

Tendon is mainly composed of collagen and an aqueous matrix of proteoglycans that are regulated by enzymes called matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). Although it is known that resistance exercise (RE) and sex influence tendon metabolism and mechanical properties, it is uncertain what structural and regulatory components contribute to these responses. We measured the mRNA expression of tendon's main fibrillar collagens (type I and type III) and the main proteoglycans (decorin, biglycan, fibromodulin, and versican) and the regulatory enzymes MMP-2, MMP-9, MMP-3, and TIMP-1 at rest and after RE. Patellar tendon biopsy samples were taken from six individuals (3 men and 3 women) before and 4 h after a bout of RE and from a another six individuals (3 men and 3 women) before and 24 h after RE. Resting mRNA expression was used for sex comparisons (6 men and 6 women). Collagen type I, collagen type III, and MMP-2 were downregulated ( P < 0.05) 4 h after RE but were unchanged ( P > 0.05) 24 h after RE. All other genes remained unchanged ( P > 0.05) after RE. Women had higher resting mRNA expression ( P < 0.05) of collagen type III and a trend ( P = 0.08) toward lower resting expression of MMP-3 than men. All other genes were not influenced ( P > 0.05) by sex. Acute RE appears to stimulate a change in collagen type I, collagen type III, and MMP-2 gene regulation in the human patellar tendon. Sex influences the structural and regulatory mRNA expression of tendon.

scholarly journals Modelling fibrillogenesis of collagen-mimetic molecules

2020 ◽  
Author(s):  
A. E. Hafner ◽  
N. G. Gyori ◽  
C. A. Bench ◽  
L. K. Davis ◽  
A. Šarić
Keyword(s):  
Extracellular Matrix ◽  
Electrostatic Interactions ◽  
Collagen Type ◽  
Collagen Type I ◽  
Coarse Grained ◽  
Cell Phenotype ◽  
Type I ◽  
Collagen Scaffolds ◽  
Crucial Component ◽  
Self Assembled

One of the most robust examples of self-assembly in living organisms is the formation of collagen architectures. Collagen type I molecules are a crucial component of the extracellular-matrix where they self-assemble into fibrils of well defined striped patterns. This striped fibrilar pattern is preserved across the animal kingdom and is important for the determination of cell phenotype, cell adhesion, and tissue regulation and signalling. The understanding of the physical processes that determine such a robust morphology of self-assembled collagen fibrils is currently almost completely missing. Here we develop a minimal coarse-grained computational model to identify the physical principles of the assembly of collagen-mimetic molecules. We find that screened electrostatic interactions can drive the formation of collagen-like filaments of well-defined striped morphologies. The fibril pattern is determined solely by the distribution of charges on the molecule and is robust to the changes in protein concentration, monomer rigidity, and environmental conditions. We show that the fibril pattern cannot be easily predicted from the interactions between two monomers, but is an emergent result of multi-body interactions. Our results can help address collagen remodelling in diseases and ageing, and guide the design of collagen scaffolds for biotechnological applications.Statement of SignificanceCollagen type I protein is the most abundant protein in mammals. It is a crucial component of the extracellular-matrix where it robustly self-assembles into fibrils of specific striped architectures that are crucial for the correct collagen function. The molecular features that determine such robust fibril architectures are currently not well understood. Here we develop a minimal coarse-grained model to connect the design of collagen-like molecules to the architecture of the resulting self-assembled fibrils. We find that the pattern of charged residues on the surface of molecules can drive the formation of collagen-like fibrils and fully control their architectures. Our findings can help understand changes in collagen architectures observed in diseases and guide the design of synthetic collagen scaffolds.

scholarly journals Morphometric analysis of the human endoneurial extracellular matrix components during aging

2021 ◽  
Vol 73 (1) ◽  
pp. 103-110
Author(s):  
Braca Kundalic ◽  
Sladjana Ugrenovic ◽  
Ivan Jovanovic ◽  
Vladimir Petrovic ◽  
Aleksandar Petrovic ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Collagen Type ◽  
Linear Regression Analysis ◽  
Collagen Type I ◽  
Nerve Fibers ◽  
Collagen Type Iv ◽  
Type I ◽  
Type Iv ◽  
Ecm Proteins ◽  
Extracellular Matrix Components

The aim of this study was to analyze the expression of extracellular matrix (ECM) proteins in human endoneurium during aging. We harvested 15 cadaveric sural nerves, distributed in 3 age groups (I: 25-44, II: 45-64, III: 65-86 years old). Histological sections were stained immunohistochemically for the presence of collagen type I, type IV and laminin, and the ImageJ processing program was used in morphometrical analysis to determine the percentages of these endoneurial proteins. In two younger groups, the endoneurial matrix of the sural nerve was composed from about equal proportions of these proteins, which may be considered a favorable microenvironment for the regeneration of nerve fibers. Linear regression analysis showed a significant increase in endoneurial collagen type IV with age, while collagen type I and laminin significantly decreased during the aging process. In cases older than 65 years, remodeling of the endoneurial matrix was observed to be significantly higher for the presence of collagen type IV, and lower for the expression of collagen type I and laminin. This age-related imbalance of ECM proteins could represent a disadvantageous microenvironment for nerve fiber regeneration in older adults. Our findings contribute to the development of therapeutic approaches for peripheral nerve regeneration.

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