Young Hoon Hong

(18F)Fluoro-deoxy-D-glucose uptake of knee joints in the aspect of age-related osteoarthritis: a case-control study

BackgroundThis study investigated 18F-fluorodeoxyglucose (18F-FDG) uptake at knee joints for determination of metabolic alteration in association with the advance of age and joint degeneration such as osteoarthritis (OA).MethodsA total of 166 knees from 83 healthy persons who presented for routine health examination and positron emission tomography-computed tomography (PET/CT) were enrolled in this study. History of knee OA and joint symptoms and signs were reviewed. The maximum standardized uptake values (SUVmax) of cartilage and mean SUV (SUVmean) between the epiphyseal plates of femur and tibia were evaluated at knee joints. Assessment of radiological bony changes was performed using the Kallgren-Lawrence (K/L) grading system with reconstructed CT images of the knee. The joint symptoms and signs were counted and used for diagnosis of clinical and radiological OA of the knee.ResultsThe SUVmean of the knee joints showed a remarkable increase with aging in females (r = 0.503, p < 0.01). Remarkable changes of SUVmean were observed with history of OA (p < 0.01). The SUVmean of joint and the intra-articular SUVmax showed higher values in clinical and radiological OA than in normal joints (p < 0.01). Joint-SUVmean showed significant correlation with OA severity graded according to K/L score (p < 0.05). The intra-articular SUVmax showed a significant increase in symptomatic joints, indicating OA in correlation with the joint-SUVmean (p = 0.01).ConclusionsThe increasing 18F-FDG uptakes of knee joints showed agreement with aging in females and clinical and radiological knee OA, indicating that the metabolic alterations were consistent with diagnosis and demographic aspect of OA as a surrogate marker for degeneration of the knee in association with aging.

Effects of hypoxia/ischemia on catabolic mediators of cartilage in a human chondrocyte, SW1353.

Cells from a human chondrocyte cell line were studied in 1% oxygen and/or a lower glucose concentration (5.5 mM), compared to the routine culture conditions of normoxia and high glucose. HIF-1α, IL-1β, IL-6, IL-8, COX-2, TNFα, LIF, MMP-3, MMP-13, and reactive oxygen species (ROS) were evaluated, respectively. Effects of hypoxia inducing expression of HIF-1α were statistically significant at 72 h (p<0.05). Increased production of ROS by hypoxia was also observed with passage of time (p<0.05). The effects of hypoxia on HIF-1α and IL-1β were potentiated by 5.5 mM glucose, especially after 48 h (p<0.05). IL-8 production was significantly induced in 1% O(2), with 5.5 mM glucose (p<0.01). IL-8 mRNA expression and production in response to IL-1β were potentiated by hypoxia/ischemia (p<0.05, p<0.01, respectively). Up-regulation of IL-1β, ROS, and IL-8 by hypoxia/ischemia in human chondrocytes may occur in correlation with HIF-1α. IL-8 response to IL-1β may be potentiated synergically by hypoxia/ischemia, as an effector of hypoxia/ischemia. The results may suggest aggressive biology of the ordinary cartilage hypoxia/ischemia in the context of arthro-degeneration.

Effects of Methotrexate on Carotid Intima-media Thickness in Patients with Rheumatoid Arthritis

The purpose of this study was to evaluate the effects of rheumatoid arthritis (RA) and antirheumatic drugs on atherosclerosis by comparing carotid intima-media thickness (CIMT) as an indicator for cardiovascular diseases (CVD). This study included 44 female RA patients who met the 2010 ACR/EULAR criteria and age-matched 22 healthy females. CIMT was measured on both carotid arteries using a B-mode ultrasound scan. The mean value of both sides was taken as the CIMT of the subject. The CIMT was evaluated according to the use of drugs, disease activity and CVD risk factors in RA patients as a case-control study. Higher CIMT was observed in RA patients as compared with healthy subjects (0.705 ± 0.198 mm, 0.611 ± 0.093 mm, respectively, P < 0.05). With adjustment for the CVD risk factors, disease activity and the use of anti-rheumatic drugs, methotrexate (MTX) only showed a favorable effect on CIMT in RA. A significantly lower CIMT was observed in RA with MTX as compared with RA without MTX (0.644 ± 0.136 mm, 0.767 ± 0.233 mm, respectively, P < 0.05). The effects were correlated with MTX dosage (β = -0.029, P < 0.01). The use of MTX should be considered in high priority not only to control arthritis but also to reduce the RA-related CVD risk to mortality.

A Case of Minimal Change Disease Treated Successfully with Mycophenolate Mofetil in a Patient with Systemic Lupus Erythematosus

The World Health Organization classifies lupus nephritis as class I to V or VI. However, a few cases of minimal change glomerulopathy have been reported in association with systemic lupus erythematosus (SLE). Mycophenolate mofetil has been shown to be effective for treatment of minimal change disease and lupus nephritis. A 24-year-old woman diagnosed with SLE five years prior to presentation complained of a mild generalized edema. The urinalysis showed microscopic hematuria and proteinuria. The assessed amount of total proteinuria was 1,618 mg/24 hours. A renal biopsy demonstrated diffuse fusion of the foot processes of podocytes on electron microscopy. Mycophenolate mofetil was started in addition to the maintenance medications of prednisolone 10 mg/day and hydroxychloroquine 400 mg/day. After six months of treatment, the microscopic hematuria and proteinuria resolved, and the total urine protein decreased to 100 mg/24 hours.

An analysis of age-related loss of skeletal muscle mass and its significance on osteoarthritis in a Korean population.

Background/Aims: This study was conducted in order to analyze the effects of sarcopenia on age-related osteoarthritis (OA) of the knee in a Korean population. Methods: All the Korean subjects who visited the Yeungnam University Medical Center Health Promotion Center between 2008 and 2012 in order to undergo a routine medical examination were enrolled. A total of 5,723 young, healthy people (2,959 males, 2,764 females) enrolled as normal subjects and 23,473 subjects (13,006 males and 10,467 females) were included for evaluation of the effects of sarcopenia on OA. There were 266 subjects who followed-up bioelectrical impedance analysis at a 4-year interval. Of 327 subjects enrolled in this study, knees with anteroposterior X-rays were assessed according to the Kellgren-Lawrence (K/L) grade. Results: Skeletal muscle mass index (SMI) and basal metabolic rate (BMR) showed a steady decrease with the advance of age (p < 0.01), but SMI showed strong positive correlation with BMR (r = 0.72, β = 30.96, p < 0.01). During the 4-year interval, BMR showed a significant decrease with aging (p < 0.01), consistently with the decrease of SMI. Knees with normal SMI were prone to be designated as K/L grade 0 or 1; however, subjects with sarcopenia showed a trend toward the higher K/L grade, classified as knee radiological osteoarthritis (ROA) (p < 0.01). Conclusions: The results of this study may indicate that sarcopenia as age-related loss of skeletal muscle mass is interactively correlated with the presence and severity of age-related OA.

Age-related NADPH Oxidase (arNOX) Activity Correlated with Cartilage Degradation and Bony Changes in Age-related Osteoarthritis

The purpose of this study was to investigate the age-related NADPH oxidase (arNOX) activity in patients with age-related knee osteoarthritis (OA). Serum and cartilage arNOX activities were determined using an oxidized ferricytochrome C reduction assay. Full-thickness knee joint cartilages obtained through total knee replacement surgery were graded according to the Outerbridge (OB) classification. Radiographic severity of OA was determined on Knee X-rays according to the Kellgren-Lawrence (K/L) grading system. Cartilage β-galactosidase, HIF-1α, and GLUT-1 expression levels were evaluated as markers for tissue senescence, hypoxia, and glycolysis. Higher arNOX activities occurred with higher levels of cartilage β-galactosidase, HIF-1α, and GLUT-1 (P = 0.002). arNOX activity in cartilages with surface defects (OB grade II, III) was higher than in those without the defects (OB grade 0, I) (P = 0.012). Cartilage arNOX activity showed a positive correlation with serum arNOX activity (r = -0.577, P = 0.023). Serum arNOX activity was significantly higher in the OA subgroup with bilateral ROA than in the OA with no or unilateral ROA (2.449 ± 0.81, 2.022 ± 0.251 nM/mL, respectively, P = 0.019). The results of this study demonstrate that OA itself is not a cause to increase arNOX activities, however, arNOX hyperactivity is related to a high degree of cartilage degradation, and a high grade and extent of ROA in age-related OA. Graphical Abstract