[Efficacy and safety of low-dose rasburicase for refractory chronic gouty arthritis]

Objective: To explore the efficacy and safety of low-dose rasburicase for refractory chronic gouty arthritis. Methods: A cohort study. The clinical data of patients with refractory chronic gouty arthritis who were treated with rasburicase at Sun Yat-sen Memorial Hospital, Sun Yat-sen University between January 2021 and July 2022 were retrospectively analyzed. Refractory chronic gouty arthritis was defined as serum uric acid (sUA)>360 μmol/L and urate volume>10 cm³ under dual-energy computed tomography after tolerable maximal oral urate-lowering therapy for at least 3 months. The administration of low-dose rasburicase was applied intravenously with total dosage ranging from 4.5 to 7.5 mg each dose, at 4-week intervals for a maximum of three doses. Efficacy was evaluated by the changes of sUA level, tophus and urate volume. Results: A total of 22 patients were included for analysis, with 95.4% (21/22) male, the mean age was (44±15) years, and the median duration of gout was 11 (6-15) years. The mean sUA at baseline was (667±112) μmol/L. The levels of sUA significantly decreased after each dose of rasburicase (P<0.001), and the median reduction of sUA after each dose of rasburicase was 568 (471-635), 187 (66-335) and 123 (49-207) μmol/L, respectively. At week 12, nine patients (40.9%) exhibited sUA<360 μmol/L and tophus disappeared in one patient. The urate volume significantly decreased at week 12 when compared with that before the first dose of rasburicase in all the patients [40 (16-172) cm³ vs 17 (7-134) cm³, P<0.001], with a median reduction rate of 41.6% (22.9%-58.5%). The everall safety of rasburicase was good, and no serious adverse reactions occurred. Conclusions: Low-dose rasburicase is well-tolerated and effective for decreasing the urate burden in patients with refractory chronic gouty arthritis. Further prospective randomized controlled trials are needed to validate these findings.

[Predictive value of anti-mutated citrullinated vimentin antibody on one-year radiographic progression in patients with rheumatoid arthritis]

Objective: To investigate the value of baseline anti-mutated citrullinated vimentin (MCV) antibody for predicting one-year radiographic progression in patients with rheumatoid arthritis (RA). Methods: Consecutive RA patients were recruited from November 2014 to July 2018 at Department of Rheumatology, Sun Yat-sen Memorial Hospital, Clinical data were collected including disease activity score in 28 joints with four variables including C-reactive protein (CRP).Serum anti-MCV antibody at baseline was detected by enzyme-linked immunosorbent assay. X ray assessment of both hands/wrists was performed and assessed according to the Sharp/van der Heijde modified score (mTSS) at baseline and the 12th month. Univariate and multivariate logistic regression analyses were used to identify the risk factors for one-year radiographic progression. Results: Among 220 RA patients recruited, the positive rate of anti-MCV antibody at baseline was 77.7%. Compared with those with negative anti-MCV antibody, RA patients with positive anti-MCV antibody had higher disease activity score in 28 joints with four variables induding CRP [3.8 (2.4, 5.0) vs. 3.1 (2.1, 4.0), P=0.007], more physical dysfunction (21.6% vs. 8.2%, P=0.033) and higher radiographic indicators including mTSS [11 (2, 27) vs. 4 (1, 10), P=0.003], joint space narrowing [JSN, 4 (0, 14) vs. 2 (0, 6), P=0.024] and joint erosion[JE, 5 (1, 18)vs. 3 (0, 5), P=0.003]. After one-year follow-up, sixty-six RA patients (30.0%) developed radiographic progression, the percentage of whom was significantly higher in positive anti-MCV group than that in negative anti-MCV group (33.9% vs.16.3%, P=0.018). Multivariate logistic regression analysis suggested that positive anti-MCV antibody at baseline was an independent risk factor for one-year radiographic progression (OR=2.341, 95%CI 1.002-5.469). Conclusion: Positive anti-MCV antibody at baseline predicts one-year radiographic progression in RA patients. In the future, anti-MCV antibody can be used not only as a supplementary laboratory marker, but also in disease activity assessment and prognosis prediction for RA.

Effect of HBx on inflammation and mitochondrial oxidative stress in mouse hepatocytes

Hepatitis B virus × protein (HBx) serves an important role in the pathogenesis of the hepatitis B virus infection. Previous studies have reported that the interaction between HBx and hepatocyte mitochondria is an important factor leading to liver cell injury and apoptosis, ultimately inducing the formation of liver cancer. In the present study, a mouse model expressing HBx was constructed using hydrodynamic in vivo transfection based on the interaction between HBx and cytochrome c oxidase (COX) subunit III. The specific mechanism of HBx-induced oxidative stress in mouse hepatocytes and the subsequent effect on mitochondrial function and inflammatory injury was assessed. The results demonstrated that HBx reduced the activity of COX and the expression of superoxide dismutase and upregulated the expression of malondialdehyde, NF-κB and phospho-AKT, thus increasing oxidative stress. In addition, HBx induced an increase in interleukin (IL)-6, IL-1β and IL-18 expression levels, which created an inflammatory microenvironment in the liver, further promoting hepatocyte inflammatory injury. Therefore, it was proposed that HBx may affect hepatocyte mitochondrial respiration by reducing the activity of cytochrome c oxidase, leading to mitochondrial dysfunction and inducing hepatocyte inflammation and injury.

[Potential mechanism of transcription factor peroxisome proliferator-activated receptor-gamma coactivator-1 beta on promoting osteoclastogenesis]

Objective: To investigate the role of transcription factor peroxisome proliferator-activated receptor-gamma coactivator-1 beta (PGC-1β) on osteoclastogenesis and related regulatory mechanism in the mouse monocyte-macrophage cell line (RAW264.7). Methods: PGC-1β expression and location in RAW264.7 cells was detected by immunofluorescence, flow cytometry and western blot analysis with nuclear protein extraction. RAW264.7 cells were transfected with lentivirus for gene silencing or over-expression of PGC-1β and cultured with macrophage colony-stimulating factor and receptor activator for nuclear factor-κB ligand. Cell viability was detected by cell counting kit-8. Cell apoptosis and cell cycle were detected by flow cytometry. Mature osteoclasts and their bone resorption activity were determined by tartrate-resistant acid phosphatase (TRAP) expression and toluidine blue staining. Western blot analysis was performed for detecting dendritic cell-specific transmembrane protein (DC-STAMP), cathepsin K, TRAP and matrix metalloproteinase (MMP)-9 expression, as well as cytoplasmic NF-κB-inducing kinase (NIK) and nuclear RelB. Results: PGC-1β expression was observed in the nuclei of RAW264.7 cells. Down-regulation or overexpression of PGC-1β in RAW264.7 cells did not affect cell viability, apoptosis or cell cycle. Down-regulation of PGC-1β decreased the count of mature osteoclasts (49±21 cells vs. 147±42 cells, P=0.004) and the pit area of bone resorption lacunae (42.11μm(2)±11.30 μm(2) vs. 204.80μm(2)±31.09 μm(2), P<0.001), as well as the expression of cathepsin K, TRAP and MMP-9, but not DC-STAMP. Overexpression of PGC-1β promoted osteoclast differentiation and bone resorption activity, as well as the expression of cathepsin K, TRAP and MMP-9. Down-regulation of PGC-1β suppressed the protein expression of cytoplasmic NIK and nuclear RelB in RAW264.7 cells. Conclusion: PGC-1β can promote the differentiation of RAW264.7 into osteoclasts and improve the bone resorption ability of the cells via activation of NIK/RelB pathway, which might be a promising therapeutic target for osteoporosis.

[Characteristics and clinical significance of body composition in gout patients]

Objective: To investigate the characteristics of body composition (BC) in gout patients and its clinical significance. Methods: Consecutive gout patients were recruited between August 2017 and December 2018. Demographic information, clinical characteristics and comorbidities were collected. BC was assessed by bioelectric impedance analysis including body fat percentage (BF%), trunk and limb BF%, appendicular skeletal muscle index. Overfat was defined by BF% ≥25% for male and ≥35% for female. The association between BC and serum uric acid (sUA) was evaluated by multiple linear regression. Results: A total of 362 gout patients were recruited with median age 38 (30, 52) years, 96.1% (348/362) were male. Mean sUA was (551±133) μmol/L. The mean BF% was (25.8±6.4)% with 53.6%(194/362) patients overfat. Male gout patients with overfat showed more affected joints [4(2, 6) vs. 2(2, 5)], higher sUA [(576±126)μmol/L vs. (523±134) μmol/L], higher prevalence of dyslipidemia [70.1%(131/187) vs. 54.0%(87/161)], metabolic syndrome [60.8%(118/187) vs. 28.0%(47/161)], fatty liver [58.2%(113/187) vs. 35.1%(59/161)] and hypertension [44.4%(83/187) vs. 25.5%(41/161)] than male patients with normal fat (all P<0.05). Their BF%, trunk BF% and limb BF% were positively correlated with the numbers of affected joints, sUA, metabolic syndrome, fatty liver, and hypertension, respectively (r=0.154-0.435, all P<0.05). Multivariable linear regression suggested that BF% (β=4.29, P=0.020) and trunk BF% (β=9.11, P=0.007), but not limb BF%, were positively correlated with sUA. Conclusion: Overfat is very common in gout patients. The proportion of trunk fat in male patients is positively correlated with sUA. When assessing obesity in gout patients clinically, body composition analysis should be performed simultaneously.

[Clinical characteristics and renal uric acid excretion in early-onset gout patients]

Objective: To investigate clinical characteristics and renal uric acid excretion in early-onset gout patients. Methods: Consecutive inpatients with primary gout were recruited between 2013 and 2017. The patients with gout onset younger than 30 were defined as early-onset group while the others were enrolled as control group. Clinical characteristics and uric acid (UA) indicators were compared between two groups. Results: Among 202 recruited patients, the early-onset group included 36 patients (17.8%). Compared with control group, the early-onset group presented more patients with obesity [13 patients (36.1%) vs. 22 patients (13.3%), P<0.05], significantly higher serum UA level [(634±124)μmol/L vs.(527±169)μmol/L] and glomerular load of UA[(7.2±2.8)mg·min(-1)·1.73m(-2) vs. (4.4±2.2)mg·min(-1)·1.73m(-2)] and estimated glomerular filtration rate (GFR) [(83±21)ml·min(-1)·1.73m(-2) vs. (67±21)ml·min(-1)·1.73m(-2)] (all P<0.05), lower fractional excretion of UA [4.4% (3.4%,6.1%) vs. 7.2% (5.2%,9.6%),P<0.05], whereas 24h urinary UA excretion was comparable [(2 788±882)μmol/1.73m(2) vs. (2 645±1 140)μmol/1.73m(2), P=0.274]. Subgroup analysis of patients without chronic kidney disease showed significantly lower fractional excretion of UA in the early-onset group [4.5%(3.3%,6.1%) vs. 6.7% (5.1%,8.7%),P<0.05]. Logistic regression analysis showed that obesity (OR=3.25) and fractional excretion of UA less than 7% (OR=9.01, all P<0.05) were risk factors of gout early onset. Conclusion: The gout patients with early-onset younger than 30 present high serum and glomerular load of uric acid which might be due to obesity and relative under-excretion of renal uric acid.

[Andersson lesion in ankylosing spondylitis: a clinical study of 14 cases]

Objective: To investigate the clinical characteristics of ankylosing spondylitis (AS) combined Andersson lesion (AL). Methods: The clinical data of patients who were diagnosed as AS combined AL at Sun Yat-sen Memorial Hospital between January 2012 and December 2015 were reviewed retrospectively.SPSS 20.0 software was used for statistical analysis.Data of normal distribution was expressed by x±s (standard deviation) and that of abnormal distribution by median and range. Results: Fourteen patients were enrolled. Ten were male, median age (IQR, similarly hereinafter) was 46 (29-53) years, disease duration was 120 (54-150) months, 7 has symptom increased in the beginning, 6 has nerve compression symptom, 7 has kyphosis, and 4 has spinous tenderness or percussion pain in physical examination.Eleven of AL occurred in the thoracolumbar junction.Erythrocyte sedimentation rate was 24 (15-44) mm/1 h, C-reactive protein was 10 (5-18) mg/L, and Serum amyloid A was 19 (5-31) mg/L.All the 14 patients were divided into 2 groups, aggravated group (n=7) and none aggravated group (n=7) according to the symptom.It was no statistic difference between them about all the above indicators. Conclusion: Imageological diagnosis should be performed to identify Andersson lesion, while ankylosing spondylitis patients combined mechanical pain based on inflammatory back pain, or mainly with nerve compression symptom, tenderness or percussion pain, or spinous, even when inflammatory markers were normal.

[grp75 protects cells from injuries caused by glucose deprivation]

To elucidate the functions of grp75, CHL cells over-expressing grp75 are cultured in glucose-free medium in order to simulate energy metabolic stress. Their susceptibilities to injuries caused by glucose deprivation are assessed by trypan blue exclusion, LDH leakage measurement and cytometry analysis. Data shows a stronger resistance to glucose deprivation among cells over-expressing grp75 than among cells constitutively expressing grp75. The outcome suggests that grp75 can protect cells from injuries caused by glucose deprivation.