Browsing by Subject "Proteoglycans"

Now showing 1 - 4 of 4
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    Alteration in epithelium and stroma of post-INTACS cornea: Ultrastructure and 3D transmission electron tomography
    (2026) Omar Kirat2; Adrian Smedowski; Aljohara Alkanaan; Fahad Almoqbel; Turki Almubrad; Saeed Akhtar; Biología Celular e Histología; Universidad de Murcia, Departamento de Biologia Celular e Histiologia
    This study was conducted to investigate the ultrastructure of the epithelium and stroma of post INTACS corneas. INTACS were surgically inserted into the corneas of three patients to remodel the keratoconus shape. INTACS were inserted with the IntraLase femtosecond laser. Patients 1, 2, and 3 returned to the clinic 8, 6, and 9 years, respectively, after surgery due to their deteriorating vision. The lamellae above the INTACS were removed surgically and processed for light and electron microscopy. 2D and 3D digital images of lamellae, collagen fibrils (CFs), and proteoglycans (PGs) were captured by a bottom-mounted camera and analysed using iTEM software. The epithelium and stromal lamellae had degenerated. A large number of aggregates of microfilaments were present in the Bowman’s layer (BW) and throughout the stroma. In the stroma, just above the INTACS insertion, lamellae were completely disorganised and running randomly in the large electron-lucent spaces. The CF diameter was significantly smaller than in the normal cornea. 3D images showed microfibrils within the CF were less in the post-INTACS cornea than in the normal cornea. We believe that insertion of the INTACS disturbed the lamellar organisation and uniform distribution of CFs. This non-uniform CF distribution increased over time, resulting in vision impairment.
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    Long-term type 1 diabetes alters the deposition of collagens and proteoglycans in the early pregnant myometrium of mice
    (F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2015) Favaro, Rodolfo R.; Raspantin, Priscila R.; Salgado, Renato M.; Forte, Zuleica B.; Zorn, Telma M.T.
    troduction: We have previously shown that long-term type 1 diabetes affects the structural organization, contractile apparatus and extracellular matrix (ECM) of the myometrium during early pregnancy in mice. Objective: This study aimed to identify which myometrial ECM components are affected by diabetes, including fibril-forming collagen types I, III and V, as well as proteoglycans, decorin, lumican, fibromodulin and biglycan. Methods: Alloxaninduced type 1 diabetic female mice were divided into subgroups D1 and D2, formed by females that bred 90- 100 and 100-110 days after diabetes induction, respectively. The deposition of ECM components in the myometrium was evaluated by immunohistochemistry/immunofluorescence. Results: The subgroup D1 showed decreased deposition of collagen types I and III in the external muscle layer (EML) and decreased collagen types III and V in the internal muscle layer (IML). Collagen types I and III were decreased in both muscle layers of the subgroup D2. In addition, increased deposition of collagen types I and III and lumican as well as decreased collagen type V were observed in the connective tissue between muscle layers of D2. Lumican was decreased in the EML of the subgroups D1 and D2. Fibromodulin was repressed in the IML and EML of both D1 and D2. In contrast, decorin deposition diminished only in muscle layers of D2. No changes were noticed for biglycan. Conclusions: Subgroups D1 and D2 showed distinct stages of progression of diabetic complications in the myometrium, characterized by both common and specific sets of changes in the ECM composition.
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    The role of proteoglycans in the reactive stroma on tumor growth and progression
    (F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2015) Coulson-Thomas, Yvette May; Gesteira Ferreira, Tarsis; Lawrence Norton, Andrew; W-Y Kao, Winston; Bonciani Nader, Helena; Coulson-Thomas, Vivien Jane
    The stroma surrounding tumors can either restrict or promote tumor growth and progression, and both the cellular and non-cellular components of the stroma play an active role. The cellular components in the surrounding stroma include tumor-associated fibroblasts, host tissue cells and immune cells. The noncellular components, which form the extracellular matrix (ECM) scaffold, include proteoglycans, collagen, proteinases, growth factors and cytokines. For tumorigenesis to occur it is necessary for tumor cells to modify the surrounding stroma. Tumor cells have mechanisms for achieving this, such as co-opting fibroblasts and modifying the ECM they produce, degrading the surrounding ECM and/or synthesizing a favorable ECM to support invasion. Proteoglycans are an important component of the ECM and play an active role in tumor growth and progression. The expression and glycosylation patterns of proteoglycans are altered in the stroma surrounding tumors and these molecules may support or restrict tumor growth and progression depending on the type and stage of tumor. In the present review we discuss the difference between the tumor promoting and restricting stromal reactions surrounding tumors and the role proteoglycans play.
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    Ultrastructure and 3D transmission electron tomography of collagen fibrils and proteoglycans of swollen human corneal stroma
    (Universidad de Murcia. Departamento de Biología Celular e Histología, 2019) Akhtar, S.; Petrovski, G.; Albert, R.; Alkanaan, A.; Kirat, O.; Khan, A.D.; Almubrad, T.
    Background. The transparency of the cornea is regulated by the unique organization of collagen fibrils (CFs) which is maintained by proteoglycans (PGs). The interlacing of CF lamellae in the anterior stroma provides the biomechanical properties of the cornea. Objective. To investigate the alterations of CFs and PGs in the swollen cornea, with special reference to the anterior stroma by using electron microscopy and 3D ultrastructural tomography. Method. Nine healthy normal scleral corneal rings (age from 40 to 65 years) were hydrated individually in deionised water to induce swelling in the cornea. Three of them were hydrated for 2hr whereas the other three were hydrated for 48hr. The remaining three scleral normal corneal rings were used as a control.The corneas were processed for electron microscopy (E M) to study the CFs and PGs. Ultrathin sections were observed using transmission electron microscopy (JOEL 1400) and digital images of CFs, PGs and lamellae were captured using a bottom mounted Quemesa camera and iTEM Soft Imaging System. The software program ‘Composerx64, version 3.4.2.0’ was used to construct individual 3D images from 120 digital images taken from -60 to +60 degree angles. Results. The 3D tomography showed the degeneration of microfibrils within the CFs of the swollen cornea. The CF diameter was significantly reduced and the interfibrillar spacing significantly increased in both the 2hr and 48hr hydrated corneas compared to the normal cornea. Within the hydrated corneas, the CF diameter was smaller and the interfibrillar spacing was increased in the middle and posterior stroma compared to the anterior stroma. The PG area in both the 2hr and the 48hr hydrated cornea was reduced in the anterior stroma, whereas it was increased in middle and posterior stroma compared to the normal cornea. The density of the PGs in both the 2hr and the 48hr samples, was reduced compared to the density of PGs in the normal cornea. Conclusion. The CFs, PGs and lamellae had degenerated, caused by swelling. 3D imaging demonstrated that the impairment of the microfibrils and PGs within the CF, is caused by the excessive hydration or swelling in the anterior as well as in the middle and posterior stroma. The lamellae of the anterior stroma which provides the biomechanical strength in the normal cornea, had degenerated in the swollen corneas due to the presence of the damaged CFs and PGs.