The ubiquitin-proteasome pathway and viral infections in articular cartilage of patients with osteoarthritis.

Many viruses can evolve different strategies to exploit the ubiquitin-proteasome pathway (UPP) for their own benefit. Some data have recently established connections between UPP and osteoarthritis (OA). The aim of this study was to determine the possible involvement of viral infections linked with the UPP in the physiopathology of OA.

Abnormal transforming growth factor-beta expression in mesenchymal stem cells from patients with osteoarthritis.

Objective: To determine the expression of the genes that code for the isoforms of transforming growth factor-beta (TGF-beta) and TGF-beta receptors (TBR) in mesenchymal stem cells (MSC) from patients with osteoarthritis (OA).

Methods: Total RNA was extracted from primary cultures of MSC and quantitative real-time reverse transcription-polymerase chain reaction was performed to analyze gene expression.

Results: MSC from patients with OA showed significantly increased total TGF-beta, TGF-beta1 isoform, TBR-II, and TBR-III mRNA expression compared to controls.

Retinal detachment and proliferative vitreoretinopathy: ophthalmic artery blood velocities, intraocular pressure, and endothelin-1.

Purpose: To analyze if endothelin-1 (ET-1) may have an effect on ophthalmic artery (OA) blood flow velocities and intraocular pressure (IOP) in retinal detachment (RD).

Methods: Using radioimmunoassay, immunoreactive (IR) ET-1 levels were tested in both plasma and subretinal fluid (SRF) specimens from patients with RD, while only plasma specimens from normal (healthy) subjects were tested. OA Doppler sonography parameters and IOP were measured in eyes with RD, with and without proliferative vitreoretinopathy (PVR), their respective healthy fellow eyes, and normal eyes.

Immunoreactive endothelin-1 in the vitreous humor and epiretinal membranes of patients with proliferative diabetic retinopathy.

Purpose: To investigate the potential role of endothelin-1 (ET-1), a potent vasoconstrictor with mitogenic properties, in the pathogenesis of proliferative diabetic retinopathy (PDR).

Methods: Plasma and vitreous samples were collected from normal patients (controls; n = 25), diabetic patients with PDR (n = 25), and diabetic patients with non-PDR (n = 25). The patients had to have epiretinal membranes (ERMs) or other ocular conditions that made them candidates for vitrectomy.

Immunoreactive ET-1 in the vitreous humor and epiretinal membranes of patients with proliferative vitreoretinopathy.

Purpose: Endothelin one (ET-1) is a vasomodulator peptide that plays a role on ocular blood flow, glial proliferation, and collagen matrix contraction by retinal pigmented epithelial (RPE) cells. Both glial and RPE cells have been involved in the formation of epiretinal membranes (ERMs). This investigation was conducted to determine whether ET-1 may be associated with ERMs, either idiopathic (IERMs) or from proliferative vitreoretinopathy (PVR).

Downregulation of the atrial natriuretic peptide/natriuretic peptide receptor-C system in the early stages of diabetic retinopathy in the rat.

Purpose: Atrial natriuretic peptide (ANP) is a known vascular antipermeability and antiangiogenic factor, but its possible alteration during the early stages of diabetic retinopathy has not yet been explored. The present study sought to investigate the expression of ANP and its receptors using a model of streptozotocin (STZ) induced diabetes in the rat.

Methods: Diabetes was induced in male Wistar rats by an intraperitoneal injection of STZ.

Atrial natriuretic peptide in the vitreous humor and epiretinal membranes of patients with proliferative diabetic retinopathy.

Purpose: Atrial natriuretic peptide (ANP) has been recently described as an endogenous inhibitor of the synthesis and angiogenic action of vascular endothelial growth factor (VEGF). Given VEGF's key role in promoting neovascularization in proliferative diabetic retinopathy (PDR), this study was designed to evaluate the possibility that ANP could be involved in the neovascular and fibrotic complications of PDR.

Methods: We determined ANP by radioimmunoassay in plasma and vitreous humor samples collected from diabetic patients with and without PDR and from non-diabetic subjects.

Natriuretic peptide system in the human retina.

Purpose: The natriuretic peptide (NP) family includes atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP). Natriuretic peptides are known to inhibit vascular cell growth and regulate vessel tone. There is also much evidence to suggest they modulate vascular permeability and angiogenesis, as well as regulating aqueous humor production in the eye.

Localization of endothelin-1 mRNA expression and immunoreactivity in the anterior segment of human eye: expression of ETA and ETB receptors.

Purpose: Endothelin-1 (ET-1), a potent vasoactive peptide, is an important regulator of intraocular pressure. Actually, there is evidence of a role for ET-1 in the pathogenesis of glaucoma. However, the expression pattern of ET-1 and its receptors, ETA and ETB, in the anterior segment of human eye are not known.