Depression, quality of life, and medical resource utilization in sickle cell disease.

Sickle cell disease (SCD) is a chronic, debilitating disorder. Chronically ill patients are at risk for depression, which can affect health-related quality of life (HRQoL), health care utilization, and cost. We performed an analytic epidemiologic prospective study to determine the prevalence of depression in adult patients with SCD and its association with HRQoL and medical resource utilization. Depression was measured by the Beck Depression Inventory and clinical history in adult SCD outpatients at a comprehensive SCD center. HRQoL was assessed using the SF36 form, and data were collected on medical resource utilization and corresponding cost. Neurocognitive functions were assessed using the CNS Vital Signs tool. Pain diaries were used to record daily pain. Out of 142 enrolled patients, 42 (35.2%) had depression. Depression was associated with worse physical and mental HRQoL scores (P < .0001 and P < .0001, respectively). Mean total inpatient costs ($25 000 vs $7487, P = .02) and total health care costs ($30 665 vs $13 016, P = .01) were significantly higher in patients with depression during the 12 months preceding diagnosis. Similarly, during the 6 months following diagnosis, mean total health care costs were significantly higher in depressed patients than in nondepressed patients ($13 766 vs $8670, P = .04). Depression is prevalent in adult patients with SCD and is associated with worse HRQoL and higher total health care costs. Efforts should focus on prevention, early diagnosis, and therapy for depression in SCD.

Osmotic loading to determine the intrinsic material properties of guinea pig knee cartilage.

Few methods exist to study cartilage mechanics in small animal joints due to the difficulties associated with handling small tissue samples. In this study, we apply an osmotic loading method to quantify the intrinsic material properties of articular cartilage in small animal joints. Cartilage samples were studied from the femoral condyle and tibial plateau of two-month old guinea pigs. Swelling strains were measured using confocal fluorescence scanning microscopy in samples subjected to osmotic loading. A histochemical staining method was developed and calibrated for quantification of negative fixed charge density in guinea pig cartilage. Site-matched swelling strain data and fixed charge density values were then used with a triphasic theoretical model for cartilage swelling to determine the uniaxial modulus of the cartilage solid matrix. Moduli obtained in this study (7.2 MPa femoral condyle; 10.8 MPa, tibial plateau) compare well with previously reported values for the tensile moduli of human and other animal cartilages determined from uniaxial tension experiments. This study provides the first available data for material properties and fixed charge density in cartilage from the guinea pig knee and suggests a promising method for tracking changes in cartilage mechanics in small animal models of degeneration.

In situ crosslinking elastin-like polypeptide gels for application to articular cartilage repair in a goat osteochondral defect model.

The objective of this study was to evaluate an injectable, in situ crosslinkable elastin-like polypeptide (ELP) gel for application to cartilage matrix repair in critically sized defects in goat knees. One cylindrical, osteochondral defect in each of seven animals was filled with an aqueous solution of ELP and a biocompatible, chemical crosslinker, while the contralateral defect remained unfilled and served as an internal control. Joints were sacrificed at 3 (n = 3) or 6 (n = 4) months for MRI, histological, and gross evaluation of features of biomaterial performance, including integration, cellular infiltration, surrounding matrix quality, and new matrix in the defect. At 3 months, ELP-filled defects scored significantly higher for integration by histological and gross grading compared to unfilled defects. ELP did not impede cell infiltration but appeared to be partly degraded. At 6 months, new matrix in unfilled defects outpaced that in ELP-filled defects and scored significantly better for MRI evidence of adverse changes, as well as integration and proteoglycan-containing matrix via gross and histological grading. The ELP-crosslinker solution was easily delivered and formed stable, well-integrated gels that supported cell infiltration and matrix synthesis; however, rapid degradation suggests that ELP formulation modifications should be optimized for longer-term benefits in cartilage repair applications.

Cartilage mechanics in the guinea pig model of osteoarthritis studied with an osmotic loading method.

OBJECTIVE: To determine the material properties of articular cartilage in the Hartley guinea pig model of spontaneous osteoarthritis. METHODS: Cartilage-bone samples from the medial femoral condyle and tibial plateau of 12 month-old guinea pig knees were subjected to osmotic loading. Site-matched swelling strains and fixed charge density values were used in a triphasic theoretical model for cartilage swelling to determine the modulus of the cartilage solid matrix. The degree of cartilage degeneration was assessed in adjacent tissue sections using a semi-quantitative histological grading scheme. RESULTS: Decreased values for both moduli and surface zone fixed charge density were associated with increasing grades of cartilage degeneration. Decreases in moduli reflect damage to the collagen matrix, which give rise to greater swelling strains. CONCLUSION: Histological evidence of cartilage degeneration was associated with impaired cartilage mechanics in the aging Hartley guinea pig.

Ascorbic acid increases the severity of spontaneous knee osteoarthritis in a guinea pig model.

OBJECTIVE: To determine whether ascorbic acid might be of benefit for the treatment of spontaneous osteoarthritis (OA) when administered over a long period of time. METHODS: We investigated the effects of 8 months' exposure to low, medium, and high doses of ascorbic acid on the in vivo development of histologic knee OA in the male Hartley guinea pig. The low dose represented the minimum amount needed to prevent scurvy. The medium dose was the amount present in standard laboratory guinea pig chow and resulted in plasma levels comparable with those achieved in a person consuming 200 mg/day (5 fruits and vegetables daily). The high dose was the amount shown in a previous study of the guinea pig to slow the progression of surgically induced OA. RESULTS: We found an association between ascorbic acid supplementation and increased cartilage collagen content but, in contrast to findings in a previous study of surgically induced OA in the guinea pig, ascorbic acid worsened the severity of spontaneous OA. Active transforming growth factor beta (TGF beta) was expressed in marginal osteophytes, whose size and number were significantly increased with increasing intake of ascorbic acid. Synovial fluid levels of cartilage oligomeric matrix protein, a biomarker of cartilage turnover, corroborated the histologic findings. CONCLUSION: Ascorbic acid has been shown to activate latent TGF beta. Prolonged intraarticular exposure to TGF beta has been shown to cause OA-like changes. We found expression of active TGF beta in osteophytes, a prominent feature of the joint histology seen in association with ascorbic acid treatment. Thus, the deleterious effects of prolonged ascorbic acid exposure may be mediated in part by TGF beta. This worsening of OA with ascorbic acid supplementation suggests that ascorbic acid intake should not be supplemented above the currently recommended dietary allowance (90 mg/day for men and 75 mg/day for women).