Whole Genome Expression Profiling of Semitendinosus Tendons from Children with Diplegic and Tetraplegic Cerebral Palsy.

Cerebral palsy (CP) is the most common movement disorder in children, with a prevalence ranging from 1.5 to 4 per 1000 live births. CP is caused by a non-progressive lesion of the developing brain, leading to progressive alterations of the musculoskeletal system, including spasticity, often leading to the development of fixed contractures, necessitating tendon lengthening surgery. Total RNA-sequencing analysis was performed on semitendinosus tendons from diplegic and tetraplegic CP patients subjected to tendon lengthening surgery compared to control patients undergoing anterior cruciate ligament reconstructive surgery. Tetraplegic CP patients showed increased expression of genes implicated in collagen synthesis and extracellular matrix (ECM) turnover, while only minor changes were observed in diplegic CP patients. In addition, tendons from tetraplegic CP patients showed an enrichment for upregulated genes involved in vesicle-mediated transport and downregulated genes involved in cytokine and apoptotic signaling. Overall, our results indicate increased ECM turnover with increased net synthesis of collagen in tetraplegic CP patients without activation of inflammatory and apoptotic pathways, similar to observations in athletes where ECM remodeling results in increased tendon stiffness and tensile strength. Nevertheless, the resulting increased tendon stiffness is an important issue in clinical practice, where surgery is often required to restore joint mobility.

Blood Thiol Redox State in Chronic Kidney Disease.

Thiols (sulfhydryl groups) are effective antioxidants that can preserve the correct structure of proteins, and can protect cells and tissues from damage induced by oxidative stress. Abnormal levels of thiols have been measured in the blood of patients with moderate-to-severe chronic kidney disease (CKD) compared to healthy subjects, as well as in end-stage renal disease (ESRD) patients on haemodialysis or peritoneal dialysis. The levels of protein thiols (a measure of the endogenous antioxidant capacity inversely related to protein oxidation) and S-thiolated proteins (mixed disulphides of protein thiols and low molecular mass thiols), and the protein thiolation index (the molar ratio of the S-thiolated proteins to free protein thiols in plasma) have been investigated in the plasma or red blood cells of CKD and ESRD patients as possible biomarkers of oxidative stress. This type of minimally invasive analysis provides valuable information on the redox status of the less-easily accessible tissues and organs, and of the whole organism. This review provides an overview of reversible modifications in protein thiols in the setting of CKD and renal replacement therapy. The evidence suggests that protein thiols, S-thiolated proteins, and the protein thiolation index are promising biomarkers of reversible oxidative stress that could be included in the routine monitoring of CKD and ESRD patients.

The Role of Taylor Spatial Frame in the Treatment of Blount Disease.

BACKGROUND: Alteration of the posteromedial part of the proximal tibia is the main characteristic of Blount's disease and if left untreated, leg alignment and normal development of the lower limbs may be compromised. AIM: To report treatment outcomes in children with Blount's disease using the Taylor Spatial Frame (TSF). MATERIALS AND METHODS: From January 2007 to December 2014, 16 young children (24 tibia) with a mean age of 7.5 years (range of 3-14 yrs) and severe Blount's disease were treated using TSF. Preoperative long standing radiographs were performed and anatomic medial proximal tibial angle (MPTA), diaphyseal-metaphyseal tibial angle (Drennan), femoro-tibial angle and leg length discrepancy (LLD) were measured. RESULTS: Post-operative improvement of all measurements was observed. MPTA increased from a mean of 71.8° (58° - 79°) to 92.5° (90° - 95°), the Drennan decreased from 16.6° (14° - 18°) to 3.6° (0° - 6°), the F-T angle changed from 15.4° (10° - 25°) of varus to 5.9° (2° - 10°) of valgus and the LLD decreased from 208 mm (150-320) to 69 mm (0- +120). Mean follow-up was 45.6 months. According to Paley's criteria pin track infection was present in 6 tibiae, while in 5 patients software changes were necessary. Recurrence was observed in 3 patients (triplets). Complete restoration of the mechanical axis was obtained at the end of the treatment. CONCLUSIONS: In the last decades, different surgical treatments have been proposed for Blount's disease (tension band plate, staples, osteotomies using external or internal fixation). External fixation using the TSF allows gradual safe correction of multiplanar deformities and is a well-tolerated technique by patients with Blount's disease.

Assessment of glutathione/glutathione disulphide ratio and S-glutathionylated proteins in human blood, solid tissues, and cultured cells.

Glutathione (GSH) is the major non-protein thiol in humans and other mammals, which is present in millimolar concentrations within cells, but at much lower concentrations in the blood plasma. GSH and GSH-related enzymes act both to prevent oxidative damage and to detoxify electrophiles. Under oxidative stress, two GSH molecules become linked by a disulphide bridge to form glutathione disulphide (GSSG). Therefore, assessment of the GSH/GSSG ratio may provide an estimation of cellular redox metabolism. Current evidence resulting from studies in human blood, solid tissues, and cultured cells suggests that GSH also plays a prominent role in protein redox regulation via S -glutathionylation, i.e., the conjugation of GSH to reactive protein cysteine residues. A number of methodologies that enable quantitative analysis of GSH/GSSG ratio and S-glutathionylated proteins (PSSG), as well as identification and visualization of PSSG in tissue sections or cultured cells are currently available. Here, we have considered the main methodologies applied for GSH, GSSG and PSSG detection in biological samples. This review paper provides an up-to-date critical overview of the application of the most relevant analytical, morphological, and proteomics approaches to detect and analyse GSH, GSSG and PSSG in mammalian samples as well as discusses their current limitations.

Intra-observer and inter-observer errors in CT measurement of torsional profiles of lower limbs: a retrospective comparative study.

BACKGROUND: The purpose of this study was to determine errors in measurement of torsional profiles (TP) (torsional femoral angle, torsional tibial angle, and femoral ankle angle) among four orthopedic surgeons, experts, and non-experts in measurement, and the learning curve. METHODS: Twenty-six lower extremities of 13 patients with spastic diplegia candidates for femoral/tibial derotational osteotomy had preoperative bilateral computer tomography (CT) scan grams to establish the TP. Each measurement was done by four orthopedic surgeons, two experienced clinicians and interpreters of CT imaging and two with limited clinical and imaging assessment experiences. Images were blinded and the surgeons made three determinations at least 5 days apart; the three angles were measured each time for each limb. Intra-observer and inter-observer variability were determined using bias, standard deviation, and interclass correlation coefficient. RESULTS: Significant inter-observer variability and bias were noted between experts and non-experts (average variability: ICC experts: 0.88 ± 0.15; ICC non-experts: 0.91 ± 0.09). For non-experts, excessive bias (25° and 14°) was observed. An associated improvement in bias with additional measurement experience indicated a potential significant learning curve for interpreting these studies. Less inter-observer variability was observed between experts. CONCLUSIONS: Measurement of TP is a reliable tool when used by experienced personnel, and their use as a preoperative tool should be reserved to ones with experience with such image assessments. Non-experts' measurements produced a weak agreement when compared to experts'.

Tendon structure and extracellular matrix components are affected by spasticity in cerebral palsy patients.

We studied the effect of spasticity-induced overload on tendons from the gracilis and semitendinosus muscles from cerebral palsy (CP) and healthy subjects (CT) stained with haematoxylineosin, Sirius red and Alcian blue. Vascularity was also characterized using an anti-CD34 antibody. Light microscopy analysis of haematoxylin-eosin stained sections revealed that the overall structure of tendons was maintained, characterized by parallel and slightly wavy collagen fibers in both CT and CP tendons. However, hypercellularity, cell rounding, increased vascularity and lipoid degeneration were observed in CP samples. Sirius red stained collagen fibers were more evident in CP tendons, suggesting an increased collagen content induced by spasticity. Alcian blue staining revealed an overall increase of glycosaminoglycans in CP tendons as observed in tendinopathy. Our results suggest that CP-induced spasticity may be considered as a chronic, persisting and repetitive loading of tendons, inducing ECM remodeling as adaptive response to increased functional demand. At the same time, the evidence of some tendinopathic-like markers in CP tendons suggests that the chronic nature of the CP condition could represent a pathologic condition, possibly leading to a transient weakness of the tissue making it more susceptible to damage from cumulative loading until an overt tendinopathy develops.