[Current status of diagnosis and treatment of chronic lymphocytic leukemia in China: A national multicenter survey research]

Objective: To understand the current status of diagnosis and treatment of chronic lymphocytic leukemia (CLL) /small lymphocytic lymphoma (SLL) among hematologists, oncologists, and lymphoma physicians from hospitals of different levels in China. Methods: This multicenter questionnaire survey was conducted from March 2021 to July 2021 and included 1,000 eligible physicians. A combination of face-to-face interviews and online questionnaire surveys was used. A standardized questionnaire regarding the composition of patients treated for CLL/SLL, disease diagnosis and prognosis evaluation, concomitant diseases, organ function evaluation, treatment selection, and Bruton tyrosine kinase (BTK) inhibitor was used. Results: ①The interviewed physicians stated that the proportion of male patients treated for CLL/SLL is higher than that of females, and the age is mainly concentrated in 61-70 years old. ②Most of the interviewed physicians conducted tests, such as bone marrow biopsies and immunohistochemistry, for patient diagnosis, in addition to the blood test. ③Only 13.7% of the interviewed physicians fully grasped the initial treatment indications recommended by the existing guidelines. ④In terms of cognition of high-risk prognostic factors, physicians' knowledge of unmutated immunoglobulin heavy-chain variable and 11q- is far inferior to that of TP53 mutation and complex karyotype, which are two high-risk prognostic factors, and only 17.1% of the interviewed physicians fully mastered CLL International Prognostic Index scoring system. ⑤Among the first-line treatment strategy, BTK inhibitors are used for different types of patients, and physicians have formed a certain understanding that BTK inhibitors should be preferentially used in patients with high-risk factors and elderly patients, but the actual use of BTK inhibitors in different types of patients is not high (31.6%-46.0%). ⑥BTK inhibitors at a reduced dose in actual clinical treatment were used by 69.0% of the physicians, and 66.8% of the physicians had interrupted the BTK inhibitor for >12 days in actual clinical treatment. The use of BTK inhibitors is reduced or interrupted mainly because of adverse reactions, such as atrial fibrillation, severe bone marrow suppression, hemorrhage, and pulmonary infection, as well as patients' payment capacity and effective disease progression control. ⑦Some differences were found in the perceptions and behaviors of hematologists and oncologists regarding the prognostic assessment of CLL/SLL, the choice of treatment options, the clinical use of BTK inhibitors, etc. Conclusion: At present, a gap remains between the diagnosis and treatment of CLL/SLL among Chinese physicians compared with the recommendations in the guidelines regarding the diagnostic criteria, treatment indications, prognosis assessment, accompanying disease assessment, treatment strategy selection, and rational BTK inhibitor use, especially the proportion of dose reduction or BTK inhibitor discontinuation due to high adverse events.

[Correlation between polycyclic aromatic hydrocarbons component phenanthrene and clinical indicators in patients on peritoneal dialysis]

Objective: To explore the correlation between polycyclic aromatic hydrocarbons (PAHs) component phenanthrene and clinical indicators in patients on continuous ambulatory peritoneal dialysis (CAPD). Methods: A total of 22 patients who underwent peritoneal dialysis catheterization and regular dialysis in the First Affiliated Hospital of Zhengzhou University from June to August 2018 were selected. Meanwhile, 18 healthy adults who underwent physical examination were also selected as the control group. Fasting blood samples were taken to detect the concentration of PAHs components for comparison, and the correlation between PAHs components and clinical indicators was further analyzed. Results: There were 22 cases in CAPD group (13 males and 9 females), and aged (45±13) years, while there were 18 cases in control group (6 males and 12 females), and aged (41±13) years. The concentration of blood phenanthrene (PHE) was the highest in CAPD group [0.449 (0.254, 0.581) mg/L], and it was only lower than acenaphthene in the control group [0.081 (0.050, 0.444) mg/L], with a statistically significant difference between the two groups (P=0.008). The analysis of PHE and clinical indicators showed that the concentration of PHE in CAPD patients was negatively correlated with weekly urea clearance index (Kt/V), weekly creatinine clearance (Ccr) and leukocyte level, but positively correlated with triglyceride level (r=-0.743, -0.749, -0.655 and 0.610, respectively, all P<0.05). Simple linear regression analysis demonstrated that for every 0.1 mg/L increase in PHE concentration, weekly Kt/V, weekly Ccr and white blood cell count decreased by 0.226, 3.050 L/1.73 m² and 0.512×10⁹/L, respectively, but triglyceride level increased by 0.152 mmol/L (all P<0.05). Multiple linear regression analysis revealed that the blood PHE concentration of CAPD patients was negatively correlated with weekly Kt/V and Ccr levels (t=-2.402 and -2.368, respectively, both P<0.05). All CAPD patients were followed up for 3 years, during which 8 patients (36.4%) withdrew from peritoneal dialysis due to technical failure, and the baseline PHE concentration was higher than that of patients who did not quit peritoneal dialysis [0.572 (0.416, 0.662) vs 0.268 (0.120, 0.475) mg/L, P=0.003]. Eight patients (36.4%) had cardiovascular events, and the baseline blood PHE concentration was higher than that of patients without cardiovascular events [0.542 (0.389, 0.741) vs 0.373 (0.157, 0.545) mg/L, P=0.045]. Conclusion: PHE correlates with clinical indicators of CAPD patients, including Kt/v, Ccr, leukocyte and triglyceride.

Breaking the Volcano-Shaped Relationship for Highly Efficient Electrocatalytic Nitrogen Reduction: A Computational Guideline

The volcano-shaped relationship is very common in electrocatalytic nitrogen reduction reaction (e-NRR) and is usually caused by the competition between the first and last hydrogenation steps. How to break such a relationship to further improve the catalytic performance remains a great challenge. Herein, using first-principles calculations, we investigate a range of transition-metal (TM)-doped Cu-based single-atom alloys (TM₁-Cu(111)) as catalysts for e-NRR. When the adsorption of N₂ on the catalysts is strong enough, the inert N₂ molecules can be effectively activated for the first hydrogenation step. Meanwhile, the last hydrogenation step is not affected by the scaling relationship and remains easy on all of the catalysts due to the unstable top-site adsorption of NH₂, resulting in the break of the volcano-shaped relationship in e-NRR. Thus, only the first hydrogenation step is identified as the potential determining step. Four TM₁-Cu(111) catalysts (TM = Re, W, Tc, and Mo) are selected as promising catalysts with limiting potential ranging from -0.38 to -0.56 V, showing outstanding e-NRR activity. Besides, the four catalysts also inhibit the competing hydrogen evolution reaction and long-term stability. Our work provides a guideline for breaking the volcano-shaped relationship in e-NRR and significant in the rational design of highly efficient electrocatalysts.

[Associations between early onset of puberty and obesity types in children: Based on both the cross-sectional study and cohort study]

OBJECTIVE

To explore and analyze the relationship between early onset of puberty and different types of obesity in children, by combining large sample cross-sectional survey data with long-term longitudinal cohort data, so as to provide clues for further clarifying the health hazards of early onset of puberty and obesity prevention and control.

METHODS

The research data were from the cross-sectional survey data of seven provinces(autonomous regions, municipalities) in China and the cohort data of adolescent development in Xiamen. The study first found the association between early onset of puberty and obesity by Logistic regression on the cross-sectional data, and then used Poisson regression to analyze the association between early puberty initiation and various types of obesity risk.

RESULTS

In the study, 43 137 and 1 266 children were included in the cross-sectional survey and cohort survey respectively. The cross-sectional study found that among the girls aged 10-13 years, compared with the girls of the same age who did not start puberty, the body mass index (BMI)-Z score of the girls in the puberty start group was 0.5-0.8 higher, and the waist circumference Z score was 0.4-0.7 higher, and the risk of various types of obesity was higher. At the same time, the early onset of puberty was positively correlated with simple obesity, central obesity and compound obesity, the OR (95%CI) were 1.86 (1.42-2.44), 1.95 (1.65-2.32) and 1.86 (1.41-2.45), respectively. No significant association was found in boys. According to the cohort data, in girls, the risk of simple obesity was 6.00 times [RR (95%CI): 6.00 (1.07-33.60)], the risk of central obesity was 3.30 times [RR (95%CI): 3.30 (1.22-8.92)], and the risk of compound obesity was 5.76 times [RR (95%CI): 5.76 (1.03-32.30)], compared with the group without early puberty initiation, while no association between early puberty initiation and obesity was found in boys.

CONCLUSION

Based on the cross-sectional survey and longitudinal cohort survey, it is confirmed that the early onset of puberty in girls may increase the risk of simple obesity, central obesity and compound obesity, while there is no significant correlation between puberty onset and obesity in boys.

POS0599 IMPACT OF TREAT-TO-TARGET THERAPY ON BONE MINERAL DENSITY LOSS IN PATIENTS WITH RHEUMATOID ARTHRITIS: A PROSPECTIVE COHORT STUDY

Background

Osteoporosis is a common comorbidity of rheumatoid arthritis (RA). Although RA disease activity has been demonstrated to be associated with bone loss in previous studies, most of them were cross-sectional studies and not in the context of treat-to-target (T2T) strategies.

Objectives

To evaluate the association of disease activity with bone mineral density (BMD) changes in the context of T2T strategies in a prospective RA cohort.

Methods

RA patients were enrolled from a prospective CENTRA cohort of Peking University First Hospital. BMD was repeated at baseline, 1-year and then every other year. Time-adjusted mean disease activity scores were adopted to reflect the overall disease activity during follow-up. The influence of univariable associations between predictors and BMD was investigated using linear regression.

Results

A total of 268 patients were included in our analysis. Their mean age was 50 (12.9) years old. At enrollment, the mean (SD) DAS28-ESR was 3.70 (1.17), and the median (IQR) CDAI and SDIA was 10 (14.45) and 10.30 (16.53), respectively. Osteoporosis at lumbar spine was observed in 23.1% patients and 9.3% at femoral neck at enrollment. Older age, higher SDAI score and lower BMI were found to be associated with osteoporosis at baseline. Reevaluations of BMD at 1 year was applied in 144 patients. Mean decreases of BMDs were 1.75 % at the lumbar spine and 1.40 % at femoral neck at 1 year form baseline, respectively. Patients who achieved remission had less yearly bone loss at lumbar spine (p=0.036). Female gender was identified as a risk factor in the multiple linear regression analyses, and lower disease activity and bisphosphonates were protective factors of continuous bone loss.

Conclusion

Disease activity is associated with bone loss in RA patients in the context of T2T strategies, and those who achieved remission had less yearly bone loss.

Disclosure of Interests

None declared

POS0720 LOW-DOSE GLUCOCORTICOIDS WITHDRAWN IN SYSTEMIC LUPUS ERYTHEMATOSUS: A DESIRABLE AND ATTAINABLE GOAL

Background

Prolonged use of GC may cause irreversible organ damage, leading to impaired quality of life and even increased mortality. However, many physicians are worried about severe flares after GC withdrawal in daily practice.

Objectives

To assess the risk of flare in systemic lupus erythematosus (SLE) patients after low dose glucocorticoids (GC) discontinuation and evaluate the risk factors of flare.

Methods

SLE patients who ever discontinued GC were identified from PKUFHS cohort. The disease flare profile after GC discontinuation were analyzed. Flare rate was analyzed using Kaplan-Meier analysis. COX regression was used to determine the effect of variables on SLE flare. A prognostic nomogram using Cox proportional hazards regression modeling were developed.

Results

132 SLE patients were eligible for the final analysis. They were followed up for a median (IQR) period of 21.8 (9.01, 36.7) months. The cumulative probability of flare after GC discontinuation was 8.3 % at 6 months, 16.8% at year 1 and 27.5% at year 2 (Figure 1A). In multivariate COX analysis, hypocomplementemia and serologically active clinically quiescent (SACQ) were independent risk factors of flare [HR 2.53, 95% CI (1.32, 4.88); HR 3.17, 95% CI (1.44, 6.97), respectively]. Age ≥ 40y at GC withdrawal and hydroxychloroquine usage were independent protective factors of flare [HR 0.53, 95% CI (0.29, 0.99); HR 0.32, 95% CI (0.17, 0.62), respectively] (Table 1). The protective effect of hydroxychloroquine was dosage related. From the prospective of different tapering strategies embodied as duration from prednisone 5mg/d to complete discontinuation, slower tapering strategy (12-24 months) significantly reduced the risk of flare compared to faster tapering strategy (< 3 months) [HR 0.30, 95% CI (0.11, 0.82), p=0.019]. The prognostic nomogram including aforementioned factors effectively predicted 1- and 2-year probability of flare-free (Figure 1B).

Table 1.

Predictors of flare by univariate and multivariate COX analysis.

UnivariatepMultivariatepMultivariatepModel 1Model 2age≥40y at GC withdrawal0.59 (0.33,1.07)0.0840.53 (0.29, 0.99)0.0490.63 (0.33, 1.18)0.147Age at onset ≥18y2.03 (0.62, 6.66)0.2442.75 (0.77, 9.85)0.1212.88 (0.81, 10.2)0.103Remission duration≥60 months since the last flare0.66 (0.35, 1.27)0.2170.81 (0.41, 1.57)0.5260.73 (0.38, 1.41)0.346history of thrombocytopenia1.73 (0.94, 3.18)0.0771.36 (0.70, 2.65)0.3591.45 (0.74, 2.83)0.278history of lupus nephritis0.86 (0.47, 1.55)0.610////Hypocomplementemia1.97 (1.06, 3.66)0.0312.53 (1.32, 4.88)0.005//anti-dsDNA positive1.25 (0.70, 2.23)0.456////SACQ (both)2.91 (1.38, 6.15)0.005//3.17 (1.44, 6.97)0.004SACQ (or)1.29 (0.73, 2.30)0.380////Hydroxychloroquine or not0.29 (0.16, 0.53)<0.0010.29 (0.15, 0.56)<0.0010.32 (0.17, 0.62)0.001Immunosuppressant or not0.77 (0.40, 1.48)0.426////

There was strong collinearity between hypocomplementemia and SACQ, so the two parameters were separated into two models. SACQ (both): anti-dsDNA positive and hypocomplementemia; SACQ (or): anti-dsDNA positive or hypocomplementemia; GC: glucocorticoids. Data were shown as HR (95% CI).

Figure 1.

Conclusion

Low-dose GC is feasibly discontinued with infrequent flare in real-life setting. SACQ and younger age are potential risk factors of SLE flare, while hydroxychloroquine usage and slow GC tapering to withdrawal can reduce relapse. The visualized model we developed may help to predict risk of flare among SLE patients who discontinued GC.

Disclosure of Interests

None declared

AB0030 THE BIOLOGICAL FUNCTION AND MECHANISM EXPLORATION OF TACI IN SJOGREN’S SYNDROME

Background

primary Sjogren’s syndrome (pSS) is a chronic autoimmune disease that affects the lacrimal, salivary and other exocrine glands. More and more studies have shown that B cells play a central role in the pathogenesis of SS.

Objectives

We intended to explore the expression of the transmembrane activator, calcium modulator and cyclophilin ligand interactor (TACI) on the B cells, its role in pSS, and possible signal transduction pathways.

Methods

We included 34 naive pSS patients who visited the rheumatology department of Peking University First Hospital, and 37 gender- and age-distribution matched healthy controls (HCs). (1) To compare the B cell subsets, expression of TACI and relevant receptors in pSS patients, peripheral blood mononuclear cells were separated to analyze the ratio of B subsets, TACI, and BAFF-R by flow cytometry; ELISA was applied to detect the serum BAFF and soluble TACI (sTACI) concentration. (2) As for functional research of TACI, CD19+ B cells separated by magnetic sorting were treated under in vitro culture circumstances with raw TACI, TACI knocked down by siRNA, and sTACI analog (telitacicept) intervention with varing doses. The apoptosis, proliferation, differentiation and regulatory capacity on T cells were analyzed by flow cytometry, inflammatory cytokines and immunoglobulin levels in the culture supernatants were detected by CBA. (3) As for TACI-associated signaling pathway exploration, based on our previous miRNA data and relevant report of high quality, miRNA associated with TACI with significantly biased expression was confirmed by RT-qPCR. Screening the target gene of the candidate miRNA, and miRNA overexpression and inhibition experiments were conducted to validate the targeted relationship in B cells. And TACI-associated signaling pathway was explored via overexpressing and inhibiting the target gene.

Results

(1) Compared to HC, peripheral blood B subsets of pSS patients exhibited a significant bias, manifesting as increased proportion of CD19+CD24hiCD38hi Breg and decreased ratio of CD19+CD24+CD38- memory B cells. The expression of TACI in all B subsets was down-regulated, while that of BAFF-R was up-regulated. Both the serum concentration of BAFF and sTACI in pSS patients increased significantly. (2) As for functional research of TACI, in the setting of raw TACI, B cells in the pSS group showed higher apoptosis rate than HC under culture in vitro, where the ligand of TACI (APRIL or BAFF) addition turned the rate comparable; more active proliferation, and impaired capacity of inducing Treg cells to secrete IL-10. When TACI was knocked down by 50%, B cells performed less late apoptosis, significantly increased proliferation, impaired differentiation, significant dysfunction of Breg itself and impaired induction of Treg cells to secrete IL-10. While telitacicept intervention increased early apoptosis rate of B cells, significantly inhibited proliferation in 500ng/mL group and impaired ability of Breg and Treg cells to secrete IL-10. Besides, increased TACI on B cells treated with telitacicept, decreased IgG and increased IgA in the culture supernatants were observed. (3) As for TACI-associated signaling pathway exploration, hsa-miR-30b-5p showed satisfactory correlation between both transmembrane and sTACI. Besides, the expression of hsa-miR-30b-5p was significantly down-regulated, and inhibition its expression in vitro could lead to differentiation retard, impaired secretion of IL-10 by Breg cells. SMAD1 was screened based on database and validated as its target gene by overexpressing and inhibiting hsa-miR-30b-5p in B cell. After targeted up- or down-regulating the transcription of SMAD1 further, the transcription of ID2 downstream the TGF-β/Hippo signaling pathway changed accordingly.

Conclusion

The expression of TACI on peripheral blood B cells was deficient in pSS patients. TACI deficiency was closely associated with the downregulation of hsa-miR-30b-5p, activating TGF-β/Hippo pathway mediated by its target gene SMAD1 and taking part in the pathogenesis of pSS.

Disclosure of Interests

None declared

[The impact of occupational aluminum exposure on workers' overall cognitive function and various cognitive fields]

Objective: To evaluate the effects of occupational aluminum exposure on workers' overall cognitive function and cognitive fields. Methods: From July to August 2019, using the method of cluster sampling, 101 and 117 workers were selected from the electrolytic aluminum workshop of an aluminum plant in a region and the maintenance workshop of a plant in the same region. The venous blood of the subjects was collected, the plasma was extracted, and the blood aluminum concentration was measured by ICP-MS. According to the blood aluminum concentration and type of work, 93 workers who were lower than the median blood aluminum concentration and in the maintenance workshop of a factory were divided into low aluminum exposure group, and 85 workers who were higher than the median blood aluminum concentration and in the electrolytic aluminum workshop of an aluminum factory were divided into high aluminum exposure group. The basic information of the respondents, was collected through the employee physical examination form. The overall cognitive function of workers was evaluated by Beijing Montreal Cognitive Assessment Scale (MoCA) . Multiple linear regression analysis and logistic regression analysis were used for multiple statistical analysis. Results: Compared with the low aluminum exposure group (25.42±1.808) , the total score of MoCA in the high aluminum exposure group (23.84±2.919) was significantly lower, and the scores of visual space, executive function, abstract and delayed recall were significantly lower (P<0.05) . Linear regression analysis showed that the total score of MoCA, visual space and executive function, naming and delayed recall were negatively correlated with blood aluminum concentration (β=-0.018、-0.008、-0.003、-0.008, P<0.05) .MOCA total score, visual space and executive function, attention, language, abstraction, orientation were positively correlated with educational level (β=0.853、0.310、0.216、0.171、0.412、0.122, P<0.05) . Logistic regression analysis showed that adjusting for age, smoking, drinking and education, blood aluminum was a risk factor for mild cognitive impairment (OR=1.017, P<0.05) ; Education level was the protective factor of mild cognitive impairment (OR=0.419, P<0.05) . Conclusion: Occupational aluminum exposure can affect the overall cognitive function of workers, and occupational aluminum exposure increases the risk of MCI.

[Application of traction metal clip with fishhook-like device in endoscopic resection]

From July 2020 to June 2021, patients in Jiangyin Hospital Affiliated to Nantong University who met the enrollment criteria were treated with the fishhook-like device during the operation to suture the postoperative wound (group A). Patients with similar conditions and similar size wounds who were treated with a "purse-string suture" to suture the wounds were retrospectively analyzed as the control group (group B). Difference in the suture rate, adverse events, time required for suturing, and number of metal clips were compared between the two groups. The time required for suturing was (7.83±2.41) min in group A and (11.00±3.31) min in group B. The difference was statistically significant (P=0.002). The number of metal clamps used in group A averaged 7.17 pieces/case, and the number of metal clamps used in group B averaged 7.06 pieces/case. The difference was not statistically significant (P>0.05).The traction metal clip with the fishhook-like device is ingeniously designed and easy to operate. It has a good suture effect on the wound after endoscopic resection and effectively prevents postoperative adverse events.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

AB0280 THE INFLUENCE OF TARGET THERAPY AS WELL AS GLUCOCORTICOIDS TAPERING ON DISEASE FLARE IN SYSTEMIC LUPUS ERYTHEMATOSUS: RESULTS FROM A PROSPECTIVE CHINESE COHORT

Background:

Treat-to-target in systemic lupus erythematosus (SLE) has been proposed for 7 years and several recommendations were developed [1]. In these recommendations, prevention of flares should be a realistic target. Meanwhile, ‘remission’ or ‘low disease activity’ was recommended as the treatment target and minimizing glucocorticoids (GC) dose or withdrawal if possible was suggested in the maintenance treatment. However, would target therapy and GC tapering/withdrawal influence disease flare?

Objectives:

To investigate the frequency and determinants of disease flare, especially the influence of target therapy as well as GC tapering on flare in Chinese lupus patients.

Methods:

The baseline and follow-up data of all consecutive patients in a prospective longitudinal lupus cohort from January 2017 to June 2020 were collected. The lupus low disease activity state (LLDAS) was defined as in Golder et al., 2019[2]. The criteria for remission were from DORIS definitions [3]. Flare was assessed using the SELENA-SLEDAI flare index [4].

Results:

We enrolled 185 patients with disease duration at recruitment of 2.3 (0.8–7.7) years. During the 26.2 (12.5-34.5) months of follow-up, 73 (39.5%) patients experienced 95 flares, including 70 mild/moderate and 25 severe flares. The incidence of flare per patient-year was 0.27. Kaplan-Meier analyses showed that compared with those who never achieved LLDAS or DORIS, the patients who achieved the target at least once had a higher flare free survival rate; meanwhile, the patients with prednisone withdrawn had significantly lower flare free rate compared with those with small dose of GC maintained (≤7.5mg/d) (Figure 1A), but among the patients with different prednisone maintain doses (7.5~5mg, 5~2.5mg, and ≤2.5mg) there was not significant difference (Figure 1B). Cox regression analysis showed that younger age at disease onset and lower Complement 3 (C3) level at recruitment were independent risk factors for flare and achieving LLDAS or DORIS ≥50% of visits was independent protective factor (Table 1).

Conclusion:

In this Chinese prospective SLE cohort, age at disease onset, C3 level at recruitment and therapeutic target achieving influenced disease flare independently and significantly. GC tapering in appropriate patients and with appropriate pace did not increase the flare rate, but prednisone withdrawal may induce more disease exacerbation, which needs to be confirmed by large prospective studies.

References:

[1]Van Vollenhoven R F, et al. Treat-to-target in systemic lupus erythematosus: recommendations from an international task force. Ann Rheum Dis, 2014. 73(6): 958-967

[2]Golder, V., et al. Lupus low disease activity state as a treatment endpoint for systemic lupus erythematosus: a prospective validation study. The Lancet Rheumatology, 2019. 1(2): p. e95-e102.

[3]van Vollenhoven R, et al. A framework for remission in SLE: consensus findings from a large international task force on definitions of remission in SLE (DORIS). Ann Rheum Dis. 2017. 76(3): 554–561.

[4]Petri M, et al. Classification and definition of major flares in SLE clinical trials. Lupus. 1999. 8(8): 685-691.

Table 1.

Determinants of disease flare by multivariate Cox regression analyses

Model 1(LLDAS) ΔModel 2(RONT) ΔModel 3(Complete RONT) ΔHR95%CIP valueHR95%CIP valueHR95%CIP valueAge at disease onset (years)†0.970.95-0.990.0040.970.95-0.990.0030.970.95-0.990.003Anti-dsDNA positive at recruitment1.340.82-2.180.2171.120.68-1.850.6491.190.73-1.960.486C3 (mg/L) at recruitment0.9980.997-0.9990.0040.9980.997-0.9990.0070.9980.997-1.0000.010Minimum prednisone dose during follow- up (mg/d)0.980.90-1.080.7161.010.94-1.080.7471.040.97-1.110.243Therapeutic target achieved≥50% of observationsΔ0.600.39-0.940.0010.540.34-0.870.0110.680.51-0.920.011

Δ In the three hazard models, the different target achievement status were included respectively.

RONT: Clinical remission on treatment; Complete RONT: Complete remission on treatment.

Disclosure of Interests:

None declared

POS1481-HPR SEXUAL EXPERIENCE IN MALE PATIENTS WITH ANKYLOSING SPONDYLITIS: RESULTS FROM A CROSS-SECTIONAL STUDY OF 113 PATIENTS

Background:

The expression and experience of sexuality is a key part of an individual self-identity1, so it is essential for both healthy individuals and patients. Patients with ankylosing spondylitis (AS) may be susceptible to sexual issues due to disease activity, dysfunction and comorbid emotional problems. However, sexuality, especially sexual experience, are rarely paid attention in patients with AS.

Objectives:

Our study aims to assess sexual experience in male patients with AS, and analyze the factors affecting sexual experience.

Methods:

This is a cross-sectional study. A total of 113 patients with AS and 46 healthy people were investigated, matched according to age and body mass index. The Sexual Experience Questionnaire is used to assess male sexual experience. Linear regression analysis is used to explore the contributions of clinical variables to worse sexual experience.

Results:

There is a significant difference in the total sexual experience score between AS patients and healthy controls (41.92±8.83 vs 46.98±8.10, P=0.0013). Also, patients with AS have a worse score in all dimensions of sexual experience, including erectile function, individual satisfaction and couple satisfaction, comparing to healthy people. In the regression model after controlling for the effects of age, disease duration and body mass index, disease activity (BASDAI), function (BASFI), mobility (BASMI, chest expansion and finger-floor distance), health index (ASAS HI), sleep quality (PSQI) and psychological status (HADS, HADS-A and HADS-D) are significant determinants of sexual experience, including erectile function (except for chest expansion), individual satisfaction (except for BASMI) and couple satisfaction (except for BASMI). See Table 1 for details.

Table 1.

Multivariable regression analysis of association between sexual experience and clinical outcomes

IndependentSexual experience total scoreErectile functionIndividual satisfactionCouple satisfactionβ (95%CI)Pβ (95%CI)Pβ (95%CI)Pβ (95%CI)PPain total-0.09 (-0.25, 0.07)0.28-0.27 (-0.58, 0.03)0.073-0.51 (-0.91, -0.100.014-0.15 (-0.32, 0.02)0.077BASDAI1.35 (-2.24, -0.45)0.003-0.42 (-0.75, -0.09)0.014-0.72 (-1.16, -0.28)0.001-0.21 (-0.40, -0.02)0.028BASFI-1.80 (-2.59, -1.01)<0.001-0.62 (-0.91, -0.32)<0.001-0.89 (-1.28, -0.50)<0.001-0.30 (-0.47, -0.13)0.001BASMI-1.04 (-2.01, -0.07)0.036-0.47 (-0.82, -0.12)0.008-0.48 (-0.96, 0.001)0.051-0.09 (-0.29, 0.12)0.413Chest expansion1.60 (0.24, 2.96)0.0210.50 (-0.004, 0.99)0.0520.74 (0.07, 1.42)0.0320.36 (0.08, 0.64)0.011Finger-floor distance-0.20 (-0.33, -0.07)0.003-0.07 (-0.11, -0.02)0.009-0.10 (-0.17, -0.03)0.003-0.04 (-0.06, -0.01)0.011ASAS HI-1.27 (-1.64, -0.91)<0.001-0.42 (-0.55, -0.28)<0.001-0.62 (-0.80, -0.43)<0.001-0.24 (-0.32, -0.16)<0.001PSQI-0.60 (-1.11, -0.09)0.021-0.19 (-0.38, -0.004)0.045-0.28 (-0.54, -0.03)0.03-0.13 (-0.23, -0.02)0.019HADS-0.53 (-0.76, -0.29)<0.001-0.18 (-0.27, -0.09)<0.001-0.24 (-0.36, -0.13)<0.001-0.10 (-0.15, -0.05)<0.001HADS-A-0.86 (-1.30, -0.42)<0.001-0.28 (-0.44, -0.12)0.001-0.42 (-0.63, -0.20)<0.001-0.17 (-0.26, -0.07)<0.001HADS-D-0.99 (-1.45, -0.53)<0.001-0.35 (-0.52, -0.19)<0.001-0.44 (-0.67, -0.21)<0.001-0.20 (-0.29, -0.10)<0.001

Conclusion:

Worse sexual experience is associated with increased disease activity, decreased function, poor mobility, decreased health index, poor sleep quality and psychological status. Therefore, special attention to worse sexual experience in patients with AS is essential to assess disease-related suffering and develop new patient management strategies.

References:

[1]Hill J, Bird H, Thorpe R. Effects of rheumatoid arthritis on sexual activity and relationships. Rheumatology (Oxford), 2003. 42(2):280-6.

Disclosure of Interests:

None declared

[Sex Estimation of Typical Adult Vertebrae Morphology in Central China Based on CT Technique]

Abstract

Objective The morphological data of the second thoracic vertebra and the third lumbar vertebra were measured by computerized tomography （CT）. The sex differences were analyzed and the discrimination equation was obtained. Methods The data of 274 adults （203 cases from experimental group and 69 cases from validation group） from central China were collected. Four linear data （maximum transverse length of vertebral body, maximum longitudinal length of vertebral body, maximum transverse length of vertebral foramen, maximum longitudinal length of vertebral foramen）, one angle data （angle between spinous processes） and two area （vertebral foramen area, total cross-sectional area of vertebral body） data of the second thoracic vertebra and the third lumbar vertebra were collected, respectively. Then three ratios ［maximum transverse length/　maximum longitudinal length of vertebral body, maximum transverse length/ maximum longitudinal length of vertebral foramen, vertebral foramen area/ （total cross-sectional area of vertebral body-vertebral foramen area）］ and one angle （angle between spinous processes） were obtained. The discriminant equation was established for sexual discriminant analysis. Results The morphology of the second thoracic vertebra and the third lumbar vertebra was related with gender. Four single index discriminant formulae and eleven multi-index discriminant formulae were established. The 69 validation group samples were substituted into the formula for testing, and the maximum discriminant accuracy rate of the single-index discriminant formula was 75%. The maximum discriminant accuracy rate of multi-index discriminant formula was 83%. Conclusion It is feasible to conduct individual sex analysis by the morphological indexes of second thoracic vertebra and the third lumbar vertebra. The indexes have important application values in practice.

Effects of IL-1β and IL-18 induced by NLRP3 inflammasome activation on myocardial reperfusion injury after PCI

OBJECTIVE

To investigate the effect of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome in the serum levels of interleukin-1β (IL-1β) and interleukin-18 (IL-18) in patients with myocardial reperfusion injury after the percutaneous coronary intervention (PCI).

PATIENTS AND METHODS

Twenty healthy controls (control group) and forty patients (treatment group) were recruited in this study. The enzyme-linked immunosorbent assay (ELISA) was used to measure the serum levels of IL-1β and IL-18 at various time points in both the control and treatment groups. Data processing and analysis were performed using the Statistical Product and Service Solution (SPSS) 22.0 software (IBM Corp, Armonk, NY, USA). Pearson's correlation coefficient test was applied in all data analyses. A difference was statistically significant when p<0.05.

RESULTS

The levels of IL-1β and IL-18 in the treatment group were significantly higher than those in the control group (p<0.05). The IL-1β level in the treatment group peaked at 0.5 h after PCI and then, gradually decreased. The multiple regression analysis showed that IL-1β level was positively correlated with levels of LDL-C and IL-18 (p<0.05, r=0.527 and 0.955 respectively), and negatively correlated with the HDL-C level (p<0.05, r=-0.34).

CONCLUSIONS

The levels of IL-1β and IL-18 significantly rose in patients with myocardial ischemia-reperfusion injury after PCI.

Effect of Lonicera japonica extract on lactation performance, antioxidant status, and endocrine and immune function in heat-stressed mid-lactation dairy cows

Here, we examined the effects of Lonicera japonica extract (LJE) on lactation performance, antioxidant status, and endocrine and immune function in heat-stressed mid-lactation dairy cows. Twenty-four healthy Chinese Holstein mid-lactation dairy cows, all with similar milk yield (30.0 ± 1.0 kg/d), parity (2.5 ± 0.3), and days in milk (105 ± 5 d) were allocated to 4 groups using a randomized complete block design: a negative control group (without LJE supplementation; CON) and groups that received LJE at 14, 28, and 56 g/d. The experiment lasted 10 wk over a hot summer, with a pre-feeding period of 2 wk. Cows were exposed to heat stress, as the average temperature-humidity index was greater than 72. The results showed that LJE had no effect on respiration rate; however, it reduced the rectal temperature of dairy cows experiencing heat stress in both a linear and quadratic manner; the lowest (39.03°C) was recorded for the LJE-28 group, lower than the CON group. Supplementation with LJE did not affect dry matter intake, milk yield, or milk composition. The majority of biochemical parameters in serum were unaffected by supplementation with different amounts of LJE; the exception was creatinine, which was reduced quadratically. Compared with the CON group, serum triiodothyronine concentrations increased significantly in the LJE-28 group. Addition of LJE to the diet increased thyroxine concentrations quadratically; values peaked at 18.62 ng/mL in the LJE-28 group. Furthermore, supplementation with increasing amounts of LJE quadratically increased the activity of glutathione peroxidase and total antioxidant capacity in serum but decreased concentration of malondialdehyde. Although we detected no differences in the concentrations of IgA, IgM, or cytokines, dairy cows in the LJE-28 group had higher IgG and IL-4 concentrations than did cows in the CON group. Supplementation with LJE increased concentrations of IgG and IL-4 in the serum quadratically but decreased that of IL-2. Finally, heat shock protein 72 concentrations in the serum tended to fall quadratically as the amount of LJE increased. In summary, LJE had no negative effects on lactation performance but helped to alleviate heat stress by improving antioxidant status and promoting endocrine and immune functions. Supplementation with LJE at 28 g/d is recommended for lactating dairy cows experiencing heat stress during hot summers.

[Interpretation for the group standards in guidelines for personal protection against coronavirus disease 2019 for diseases control person]

As an emerging infectious disease, the COVID-19 threatened the safety of personnel in the prevention and control during the COVID-19 pandemic. Beijing Association of Preventive Medicine organizes the Beijing CDC and other organizations drafted the group standard entitled "Guidelines for personal protection against coronavirus disease 2019 for diseases control person (T/BPMA 0002-2020)" , according to years of scientific research on personal protection. Based on the principles of emphasizing the scientific, normative and safe nature, the standard was drafted to put forward the reasonable selection and correct use of personal protective equipment for disease control personnel, as well as the procedures for personal protective equipment. The standard provided a standardized basis for ensuring the safety of disease control personnel in contacting and handling of the new coronary pneumonia outbreaks with high risks.

sp2/sp3 Hybridized Carbon as an Anode with Extra Li-Ion Storage Capacity: Construction and Origin

Doping in carbon anodes can introduce active sites, usually leading to extra capacity in Li-ion batteries (LIBs), but the underlying reasons have not been uncovered deeply. Herein, the dodecahedral carbon framework (N-DF) with a low nitrogen content (3.06 wt %) is fabricated as the anode material for LIBs, which shows an extra value of 298 mA h g^-1 during 250 cycles at 0.1 A g^-1. Various characterizations and theoretical calculations demonstrate that the essence of the extra capacity mainly stems from non-coplanar sp²/sp³ hybridized orbital controlling non-Euclidean geometrical structure, which acts as new Li-ion active sites toward the excess Li⁺ adsorption. The electrochemical kinetics and in situ transmission electron microscope further reveal that the positive and negative curvature architectures not only provide supernumerary Li⁺ storage sites on the surface but also hold an enhanced (002) spacing for fast Li⁺ transport. The sp²/sp³ hybridized orbital design concept will help to develop advanced electrode materials.

[A study on the relationship between insufficient sleep and obesity among children and adolescents in China]

Objective: To analyze the relationship between insufficient sleep and obesity or central obesity in Chinese Han children and adolescents aged 9-18 years. Methods: A total of 172 710 students who participated in the 2014 Chinese National Survey on Students Constitution and Health with complete data of sleep duration and physical examination, were selected as study subjects. Insufficient sleep was defined, according to the amount of sleep for pediatric populations recommended by the American Academy of Sleep Medicine. Obesity and central obesity of children and adolescents were judged by experts from the Group of China Obesity Task Force and Health Industry Standards in China. Differences between groups were compared by using the t test or χ(2) test. Logistic regression method was applied to assess the relationship between insufficient sleep and obesity or central obesity. Results: In 2014, numbers of students with insufficient sleep, obesity and central obesity among Chinese Han children and adolescents aged 9-18 years appeared as 133 410 (77.2%), 11 145 (6.5%), and 12 603 (17.8%), respectively. Among the students with insufficient sleep, 8 358 (6.3%) were with obesity and 12 244 (17.9%) were with central obesity. The prevalence of obesity and central obesity among boys with insufficient sleep was higher than that in girls. Pupils with insufficient sleep showed the highest prevalence of obesity and central obesity. After controlling for potential confounders, the risk of obesity appeared an increase of 14.5% (OR=1.145, 95%CI: 1.092-1.200) and the risk of central obesity increased by 12.7% (OR=1.127, 95%CI: 1.078-1.178) in students with insufficient sleep, when compared with those with adequate sleep. Compared with those whose daily sleep duration was less than 6 hours, the ones who slept 7-10 hours per day showed significantly reduction on the risk of obesity and central obesity in students. Conclusions: Insufficient sleep significantly increase the risk of obesity and central obesity in children and adolescents while adequate sleep of 7-10 hours per day would reduce the risk of obesity and central obesity in students.

AB0148 ANALYSIS OF DIFFERENTIALLY EXPRESSED GENES AND MICRORNAS OF B CELLS IN PRIMARY SJOGREN’S SYNDROME BY RNA SEQUENCING

Background:

Primary Sjogren’s syndrome (pSS) is a chronic autimmune disease mainly characterized by the inflammation of exocrine glands. There two key insights into pSS pathogenesis, which included “IFN signature” and hyperactivity of B cells. mRNA and microRNA (miRNA) are very important to control the gene expression.

Objectives:

In this research, we analyzed the differentially expressed genes (DEG) and miRNA of B cells in pSS patients by RNA-sequencing. And we aim to preliminarily screen out some special miRNAs and target gene loci that may be involved in transcription regulation of B cells of pSS.

Methods:

Peripheral blood samples from 3 pSS patients and 3 age-matched healthy controls (HC) were collected. CD19+B cells were sorted by Magnetic cell sorting method. Total RNA was extracted and cDNA of transcriptome or miRNA analysis were prepared and RNA-sequencing was performed to screen the DEG and miRNA. The GO Terms was used to uncover the biological function of DEGs, and the KEGG pathway enrichment was used to find out the related signal pathway. The mRNA-miRNA conjoint analysis was also performed.

Results:

There were a total of 73 significantly DEGs in B cells of pSS patients compared to HC, including 51 upregulated DEGs (such asIFI44L,IFI44,IFIT1,IFITM1,IFIT3,IFIT2,IRF7,IFI6andISG15)and 22 downregulated DEGs (such asESR2andEGR1). GO Terms and KEGG pathway analyses showed that most of the upregulated DEGs were enriched in IFN signaling and IFN regulatory pathway, and also showed the relationship with microbial infection, such as influenza A virus, hepatitis C virus, measles and herpes simplex virus.

There were five significantly differentially expressed miRNAs, including hsa-miR-4485-3p, hsa-miR-144-5p, hsa-miR-144-3p, hsa-miR-451a, hsa-miR-4732-3p. GO Terms and KEGG pathway analyses showed that most of the target genes which regulated by those miRNAs were enrichment on herpes simplex virus and TGF-β signaling pathway.

DEG and differentially expressed miRNAs conjoint analysis showed that the target DEGs which regulated by those miRNAs participated in cytoskeleton formation and modification of DNA or RNA, such asRASD2,CKAP4,SPARS2L METTL.

Conclusion:

There were 51 upregulated DEGs and 22 downregulated DEGs in B cells of pSS patients. GO Terms and KEGG pathway analyses showed that most of the upregulated DEGs were enriched in IFN related signaling pathway, and also showed the significant relationship with microbial infection.

Conjoint analysis showed that the target DEGs which regulated by differentially expressed miRNAs participated in cytoskeleton formation and modification of DNA or RNA. There maybe more than one regulatory methods lead to DEGs in B cells of pSS patients.

Disclosure of Interests:

None declared

OP0093 FREQUENCIES AND PREDICTORS OF THE LUPUS LOW DISEASE ACTIVITY STATE AND REMISSION IN TREATMENT-NAÏVE PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS -- A REAL-WORLD COHORT STUDY

Background:

After the introduction of treat-to-target strategy in systemic lupus erythematosus (SLE), Lupus Low Disease Activity State (LLDAS) and definitions of remission in SLE (DORIS) were developed and validated. Several studies had demonstrated that the achievement and maintenance of LLDAS or DORIS was associated with good prognosis.

Objectives:

To evaluate the attainability of LLDAS and DORIS in a treatment-naïve cohort of SLE.

Methods:

LDAS5 was defined as LLDAS with a prednisone dose ≤5 mg/d. There were 4 definitions in DORIS: clinical remission on treatment (RONT), complete RONT, clinical remission off treatment (ROFT) and complete ROFT. The treatment-naïve patients from Peking University First Hospital SLE cohort were enrolled. The time to each state and their annual cumulative probabilities were estimated by Kaplan-Meier approach. The frequencies of patients who achieved each component of LLDAS or DORIS during follow-up were determined.

Results:

A total of 218 treatment-naïve patients were included, with a median follow-up of 4.48 years. Respectively, 190 (87.2%), 160 (73.4%), 148 (67.9%), 94 (43.1%), 23 (10.6%) and 18 (8.3%) patients achieved LLDAS, LLDAS5, clinical RONT, complete RONT, clinical ROFT and complete ROFT at least once during the follow-up time. The median time to LLDAS, LLDAS5, clinical RONT and complete RONT were 1.4, 2.3, 2.6 and 4.7 years, respectively.

Table 1.

Frequencies, time to achieve and annual cumulative probabilities of each state by Kaplan-Meier approach

StatesAchieved patientsNumber (%)Time to achieve(years)Cumulative probabilities of achievement (%)Year 1Year 2Year 3Year 4Year 5LLDAS190 (87.2)1.418.869.786.789.192.6LLDAS5160 (73.4)2.36.940.763.376.082.3Clinical RONT148 (67.9)2.65.536.156.168.876.6Complete RONT94 (43.1)4.74.122.637.545.350.4Clinical ROFT23 (10.6)NA1.42.95.46.710.6Complete ROFT18 (8.3)NA0.92.54.84.88.8Table 2.

Patients who achieved each component of LLDAS or DORIS during follow-up

ComponentsNumber (%)SLEDAI-2K ≤4, with no activity in major organ systems (renal, central nervous system, cardiopulmonary, vasculitis, fever), and no haemolytic anaemia or gastrointestinal active213 (97.7)Clinical SLEDAI-2K =0210 (96.3)PGA ≤1217 (99.5)PGA <0.5199 (91.3)Serology (anti-dsDNA and complement) negative148 (67.9)Prednisone dose ≤7.5 mg/day201 (92.2)Prednisone dose ≤5 mg/day171 (78.4)No prednisone dose40 (18.3)No prednisone dose and Immunosuppressants32 (14.7)

Conclusion:

Our data confirmed that LLDAS is an attainable early treatment target for SLE. Though with more difficulty, RONT can be achieved in two-thirds of our patients. ROFT may not be an ideal treatment target at present as it is only attained in few patients.

References:

[1]Franklyn, K. et al. Ann Rheum Dis. 2016 Sep;75(9):1615-21.

[2]van Vollenhoven, R. et al. Ann Rheum Dis. 2017 Mar;76(3):554-561.

Disclosure of Interests:

None declared

AB0376 DETERMINANTS AND PROTECTIVE EFFECTS OF A LOW DISEASE ACTIVITY STATE IN SYSTEMIC LUPUS ERYTHEMATOSUS: RESULTS FROM A PROSPECTIVE CHINESE COHORT

Background:

The concept of treat to target in systemic lupus erythematosus has moved forward in recent years. The Lupus low disease activity state (LLDAS) defined by the Asia-Pacific Lupus Collaboration (APLC) in 2016 has been validated prospectively in the APLC cohort itself and retrospectively in multiple other cohorts.

Objectives:

The concept of treat to target in systemic lupus erythematosus has moved forward in recent years. The Lupus low disease activity state (LLDAS) defined by the Asia-Pacific Lupus Collaboration (APLC) in 2016 has been validated prospectively in the APLC cohort itself and retrospectively in multiple other cohorts. The aim of this study was to investigate the frequency and determinants of achieving LLDAS, and the influence of LLDAS on short term outcomes including disease flare and damage accrual in Chinese lupus patients.

Methods:

The baseline and follow-up data of all consecutive patients in a longitudinal lupus cohort from January 2017 to December 2018 were collected prospectively. SLEDAI-2K, PGA and disease flare were assessed at each follow-up visit, and further compared to the previous routine clinical visits. Irreversible disease damage was captured using the SLICC damage index and the short form (36) health survey for health-related quality of life was completed annually.

Results:

One hundred and forty-nine patients were enrolled, with the median disease duration at recruitment of 2.4 (0.9–8.2) years, and median follow-up of 15.4 (10.1-18.2) months. By the end of the study, 104 (69.8%) patients achieved LLDAS at least once; 59 patients achieved LLDAS for≥50% of observations. Multivariate logistic regression analysis showed that age at disease onset< 30 years (OR=0.05, 95%CI [0.01-0.59], p=0.017), 24-hour urine total protein (UTP) level at recruitment (OR=0.9992, 95%CI [0.9987-0.9998], p=0.007), and C3 level (OR=1.004, 95%CI [1.001-1.008], p=0.024) had independent associations with achieving LLDAS for≥50% of all observations (Table 1). During follow-up, 56 (37.6%) patients experienced disease flare including 14 (9.4%) patients with severe flare. Kaplan-Meier analyses showed significant differences in flare rates according to whether LLDAS was achieved and the percentage follow-up time in LLDAS (Figure 1). Multivariate cox analysis revealed that the percentage time of time in LLDAS was an independent negative determinant of disease flare (HR=0.18, 95% CI [0.07-0.48], p=0.001) (Table 2). There were 16 (15.0%)/107 patients who had damage accrual after one year of follow-up. Multivariate logistic analysis showed a tendency for achieving LLDAS during follow-up being protective for damage accrual (OR=0.27, 95%CI [0.07-1.00], p=0.050).

Conclusion:

In this Chinese early disease cohort, LLDAS was an attainable goal in clinical practice. Age at onset, UTP and C3 level at recruitment influenced achievement of LLDAS. LLDAS was negatively associated with disease flare and damage accrual; this needs to be confirmed by future longer follow-up.

Acknowledgments:

The data in this cohort was collected and recorded using the framework of the lupus low disease activity status (LLDAS) study from the Asia-Pacific Lupus Collaboration (APLC).

Disclosure of Interests:

Yanjie Hao: None declared, Lanlan Ji: None declared, Dai Gao: None declared, Yong Fan: None declared, Eric F. Morand Grant/research support from: AstraZeneca, Consultant of: AstraZeneca, Speakers bureau: AstraZeneca, Mandana Nikpour: None declared, Zhuoli Zhang: None declared

THU0120 OVERLAPPING SJOGREN’S SYNDROME AND ULTRASOUND REMISSION, FUNCTIONAL DISABILITY AND MANAGEMENT IN RHEUMATOID ARTHRITIS PATIENTS: A PROPENSITY SCORE MATCHED REAL-WORLD COHORT FROM 2009 TO 2019

Background:

Rheumatoid arthritis (RA) patients with Sjogren’s syndrome (SS) are often referred to as more severe synovitis.

Objectives:

We intend to clarify the impact of overlapping SS on ultrasound remission, functional ability improvement and clinical decision-making in RA patients in a real-world cohort from 2009 to 2019.

Methods:

The medical records of RA patients in our medical center from 2009 to 2019 were reviewed. Cox proportional hazards models of ultrasound remission and health assessment questionnaire (HAQ) improvement were conducted in both the 1-to-1 nearest propensity score matched (PSM) and unmatched cohorts between those RA patients with SS (RA-SS) and without (RA-noSS) to correct critical confounders. Four kinds of PSM methods were used and the corresponding average treatment effect on the treated (ATT) was calculated to clarify the effect of overlapping SS on distinguishable characteristics or drug prescription in RA patients.

Results:

A total of 1100 RA patients were included in the study, of which 133 (12.1%) overlapped with SS. Among 256 patients consisting of 128 RA-SS and 128 RA-noSS after 1-to-1 nearest PSM, overlapping SS was associated with a 44%, 32% lower probability of reaching ultrasound remission, no-functional disability in RA patients, respectively. More prevalent interstitial lung disease (ILD), leukopenia, hypergammaglobulinemia, rheumatoid factor (RF) positivity, higher erythrocyte sedimentation rate (ESR) and more hydroxychloroquine (HCQ) usage, less biologic disease-modifying anti-rheumatic drugs (bDMARDs) prescription were confirmed to be correlated with overlapping SS by the robust PSM.

Conclusion:

Overlapping SS is associated with a lower probability of reaching ultrasound remission and functional activity improvement, higher prevalence of ILD, leukopenia and hypergammaglobulinemia in RA patients. Weaker interventions such as HCQ may be the mainstream of clinical decision making.

Table.

Hazard Ratios for Ultrasound Remission/No Functional Disability Associated with Overlapping SS

Unmatched cohortMatched cohortUS remissionNo functional disabilityUS remissionNo functional disabilityUnstratified0.63 (0.51, 0.79)0.60 (0.52, 0.70)0.56 (0.42, 0.74)0.68 (0.55, 0.83)Stratified Gender0.62 (0.50, 0.77)0.63 (0.54, 0.74)0.53 (0.40, 0.71)0.66 (0.54, 0.80) Age0.63 (0.51, 0.78)0.60 (0.52, 0.70)0.54 (0.40, 0.72)0.62 (0.50, 0.76) RF0.64 (0.52, 0.80)0.63 (0.54, 0.73)0.56 (0.42, 0.74)0.68 (0.55, 0.83) ACPA0.63 (0.51, 0.79)0.59 (0.50, 0.68)0.57 (0.43, 0.76)0.63 (0.51, 0.78) Seropositivity0.64 (0.52, 0.80)0.63 (0.54, 0.74)0.59 (0.45, 0.79)0.75 (0.61, 0.92) RA duration0.64 (0.51, 0.79)0.61 (0.52, 0.71)0.58 (0.44, 0.77)0.70 (0.57, 0.86) BLDAS28CRP0.64 (0.51, 0.80)0.62 (0.53, 0.72)0.54 (0.41, 0.72)0.66 (0.54, 0.81)

Values are presented as total and stratified Hazard Ratio (95% CI) for ultrasound remission and no functional disability associated with overlapping SS in RA patients according to gender, age, RF/ACPA status, RA duration and DAS28-CRP at 1stvisit. US remission refers to ultrasound GS<2 and PD=0. Unmatched cohort refers to whole sample (n=1100), matched cohort refers to propensity score matched (PSM) patients (n=256). The values are statistically significant at the level of 0.01.

Disclosure of Interests:

None declared

SAT0060 OVERLAPPING SJOGREN’S SYNDROME REDUCES THE PROBABILITY OF REACHING TARGET IN RHEUMATOID ARTHRITIS PATIENTS: A PROPENSITY SCORE MATCHED REAL-WORLD COHORT FROM 2009 TO 2019

Background:

Overlapping Sjogren’s syndrome (SS) is not uncommon in rheumatoid arthritis (RA), and considered as a probable detrimental factor of RA. But data on the impact of overlapping SS on RA therapeutic response is limited.

Objectives:

Our current study aimed to identify the effect in a real-world cohort from 2009 to 2019.

Methods:

The medical records of RA patients who attended the outpatient department of our medical center from 2009 to 2019 were reviewed, and the disease activity based on DAS28-ESR, DAS28-CRP, SDAI and CDAI at each follow-up point were collected. To correct confounders which may affect the therapeutic response between those RA patients with SS (RA-SS) and without (RA-noSS), we compared both the propensity score-matched and unmatched cohorts using the Cox proportional hazards model.

Results:

Among the 1099 RA patients, 129 (11.7%) overlapped with SS validated by positive anti-SSA or pathological minor salivary gland biopsy (MSGB). After propensity score matching based on their baseline characteristics, 126 of 129 RA-SS and 126 of 970 RA-noSS patients were statistically extracted. Overlapping SS was associated with a 29%, 26%, 18%, 22% lower probability of reaching remission in RA patients based on DAS28-ESR, DAS28-CRP, SDAI, CDAI, respectively, which trend kept true for reaching low disease activity (LDA) either. Although overlapping SS had the most significant impact on ESR (HR 0.69, 95%CI 0.61-0.79), other components assessing RA disease activity were also in jeopardy. When stratified by age, RA duration, RF and ACPA status, baseline DAS28-CRP, the trend remained.

Conclusion:

Overlapping SS is associated with a lower probability of reaching target in RA patients, and should be regarded as one of the poor prognostic factors in the management of RA.

Table

Hazard Ratios for Reaching Remission/Low disease activity and Individual Components in RA patients Associated with Overlapping SS

Unmatched cohort(n=1099)Matched cohort(n=252)Trimmed cohort(n=242)Remission Based on Composite Disease Activity ScoreDAS28-ESR0.68 (0.62, 0.75)0.71 (0.62, 0.82)0.74 (0.64, 0.85)DAS28-CRP0.80 (0.74, 0.87)0.74 (0.66, 0.83)0.74 (0.66, 0.83)SDAI0.82 (0.74, 0.91)0.82 (0.70, 0.94)0.83 (0.72, 0.97)CDAI0.77 (0.70, 0.86)0.78 (0.67, 0.91)0.78 (0.67, 0.91)Boolean0.83 (0.75, 0.92)0.80 (0.69, 0.93)0.82 (0.70, 0.95)Remission/LDA Based on Composite Disease Activity ScoreDAS28-ESR0.76 (0.70, 0.82)0.73 (0.65, 0.82)0.74 (0.66, 0.83)DAS28-CRP0.80 (0.74, 0.86)0.76 (0.68, 0.84)0.75 (0.68, 0.84)SDAI0.79 (0.73, 0.85)0.74 (0.66, 0.82)0.74 (0.66, 0.82)CDAI0.78 (0.73, 0.84)0.74 (0.66, 0.82)0.74 (0.66, 0.82)Individual Components of Disease Activity Score28SJC≤10.83 (0.77, 0.89)0.77 (0.69, 0.85)0.76 (0.68, 0.84)28TJC≤10.81 (0.75, 0.87)0.79 (0.70, 0.88)0.78 (0.70, 0.88)PtGA≤10.81 (0.74, 0.89)0.82 (0.71, 0.94)0.82 (0.72, 0.95)PrGA≤10.81 (0.74, 0.88)0.78 (0.69, 0.88)0.79 (0.70, 0.89)ESR≤ULN0.66 (0.61, 0.73)0.69 (0.61, 0.79)0.74 (0.65, 0.84)CRP≤1mg/dL0.84 (0.78, 0.90)0.76 (0.68, 0.84)0.77 (0.69, 0.85)

Disclosure of Interests:

None declared

THU0247 FREQUENCY AND PREDICTORS OF THE LUPUS LOW DISEASE ACTIVITY STATE IN CHINESE PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS: AN OBSERVATIONAL COHORT STUDY

Background:

As a consensus-based definition of minimally acceptable disease activity in systemic lupus erythematosus (SLE), Lupus Low Disease Activity State (LLDAS) has been well-validated and widely accepted. However, no data about the time to LLDAS in Asian ethnicity has been reported so far.

Objectives:

To estimate the time to LLDAS and the predictors of time to LLDAS in our prospective observational cohort of Chinese patients with SLE.

Methods:

Patients were from Peking University First Hospital SLE cohort and those having not fulfilled LLDAS at enrolment were included in this study. The time to LLDAS and annual cumulative probabilities of LLDAS achievement were estimated by the Kaplan-Meier approach. The predictors of time to LLDAS were identified by univariate and multivariable Cox proportional hazards.

Results:

A total of 574 patients with SLE were included and 435 (75.8%) of them achieved LLDAS during a median 4.2 years of follow-up. The median time to LLDAS was 19.0 months and the cumulative probabilities at 1, 2, 3, 5 and 10 years were 19.8%, 57.6%, 72.0%, 85.1% and 98.0%, respectively. In multivariable Cox models, older age at disease onset, treatment-naïve and hydroxychloroquine prescription were found to be independent predictors of shorter time to LLDAS, after adjusted by daily prednisone dose, SLE Disease Activity Index 2000 and physician’s global assessment. Finally, we developed a matrix model based on the identified independent predictors to present the time to LLDAS in patients with respective characteristics.

Conclusion:

Our study proved that LLDAS is attainable as an early treatment target for SLE in Chinese patients. The older age at disease onset, treatment-naïve and hydroxychloroquine prescription were independent predictors of shorter time to LLDAS.

References:

[1]Franklyn K, Lau CS, Navarra SV, Louthrenoo W, Lateef A, Hamijoyo L, Wahono CS, Chen SL, Jin O, Morton S, Hoi A, Huq M, Nikpour M, Morand EF; Asia-Pacific Lupus Collaboration. Ann Rheum Dis. 2016 Sep;75(9):1615-21.

Table 1

Baseline variables associated with LLDAS achievement based on multivariable Cox models

CharacteristicsModel 1Model 2Model 3HR (95% CI)pvalueHR (95% CI)pvalueHR (95% CI)pvalueAge at disease onset, years1.010 (1.003-1.016)0.0051.009 (1.002-1.016)0.0101.010 (1.003-1.017)0.004Treatment-naïve1.346 (1.105-1.641)0.0031.425 (1.161-1.749)0.0011.484 (1.204-1.830)<0.001Nephritis0.776 (0.641-0.939)0.0091.066 (0.820-1.385)0.6340.925 (0.737-1.160)0.498SLEDAI0.968 (0.950-0.987)0.001PGA0.685 (0.551-0.853)0.001Daily prednisone (or equivalent) dose, mg/d1.003 (0.998-1.007)0.2661.005 (0.999-1.010)0.093HCQ1.638 (1.263-2.123)<0.0011.713 (1.318-2.225)<0.0011.664 (1.284-2.157)<0.001

Disclosure of Interests:

None declared

[Features of gut microbiota in patients with idiopathic Parkinson's disease]

Objectives: To investigate whether the fecal microbiome of Parkinson's disease patients differs from that of healthy population and explore the pathogenesis and new treatment of idiopathic Parkinson's disease. Methods: A total of 30 patients diagnosed as idiopathic Parkinson disease (PD group) in Beijing Friendship Hospital between April 2017 and June 2018 were enrolled and 30 healthy controls (NC group) were recruited at the same time.Medical records and score of unified Parkinson's disease rating scale (UPDRS) were collected and fresh fecal samples were obtained and stored in refrigerator (-80℃). The microbial compositions of fecal samples were investigated by 16S rRNA gene sequencing targeting the V3-V4 region. The taxa abundance and microbial composition were tested. Results: There was no difference of age and sex in PD and NC groups. Chao1 and Shannon indexes tended to be higher in PD group, yet failed to reach statistic significance (P=0.115 and 0.052). Relative abundance of gut microbiota differed in each taxonomic category. The relative abundance of Firmicutes in PD group was 53.6%(41.7%-64.8%), while that of Bacteroidetes in NC group was 51.7%(31.7%-65.3%). The ratios of Firmicutes to Bacteroidetes were significantly different between the two groups (1.6(0.9-3.4) vs 0.7(0.5-1.4), P=0.001). In Clostridia, Bacilli and Erysipelotrichia of Firmicutes, the relative abundances of Clostridiales, Christensenellaceae, Peptoclostridium, Lactobacillus and Erysipelatoclostridium were higher in PD group (P=0.024, 0.046, 0.036, 0.022 and 0.037). The relative abundance of Prevotella of Bacteroidales, was lower in PD group, yet failed to reach statistic significance (P=0.121). The relative abundances of Alistipes of Rikenellaceae and Butyricimonas of Marinilabiliales in PD group were significantly higher than those in NC group (P=0.047 and 0.033). The relative abundance of Bifidobacterium of Actinobacteria was significanly higher in PD group when compared with NC group (P=0.009). Despite the relatively low abundance, Akkermansia of Verrucomicrobia was significantly higher in PD group than in NC group (P=0.025). Conclusion: The structures of the fecal microbiota differ significantly between PD patients and healthy controls.

Regulating Charge Transfer of Lattice Oxygen in Single-Atom-Doped Titania for Hydrogen Evolution

Single-atom catalysts have attracted much attention. Reported herein is that regulating charge transfer of lattice oxygen atoms in serial single-atom-doped titania enables tunable hydrogen evolution reaction (HER) activity. First-principles calculations disclose that the activity of lattice oxygen for the HER can be regularly promoted by substituting its nearest metal atom, and doping-induced charge transfer plays an essential role. Besides, the realm of the charge transfer of the active site can be enlarged to the second nearest atom by creating oxygen vacancies, resulting in further optimization for the HER. Various single-atom-doped titania nanosheets were fabricated to validate the proposed model. Taking advantage of the localized charge transfer to the lattice atom is demonstrated to be feasible for realizing precise regulation of the electronic structures and thus catalytic activity of the nanosheets.

Multifunctional phototheranostic nanomedicine for cancer imaging and treatment

Cancer, as one of the most life-threatening diseases, shows a high fatality rate around the world. When improving the therapeutic efficacy of conventional cancer treatments, researchers also conduct extensive studies into alternative therapeutic approaches, which are safe, valid, and economical. Phototherapies, including photodynamic therapy (PDT) and photothermal therapy (PTT), are tumor-ablative and function-reserving oncologic interventions, showing strong potential in clinical cancer treatment. During phototherapies, the non-toxic phototherapeutic agents can be activated upon light irradiation to induce cell death without causing much damage to normal tissues. Besides, with the rapid development of nanotechnology in the past decades, phototheranostic nanomedicine also has attracted tremendous interests aiming to continuously refine their performance. Herein, we reviewed the recent progress of phototheranostic nanomedicine for improved cancer therapy. After a brief introduction of the therapeutic principles and related phototherapeutic agents for PDT and PTT, the existing works on developing of phototheranostic nanomedicine by mainly focusing on their categories and applications, particularly on phototherapy-synergized cancer immunotherapy, are comprehensively reviewed. More importantly, a brief conclusion and future challenges of phototheranostic nanomedicine from our point of view are delivered in the last part of this article.

Spin transport properties of 1,4,5,8-naphthalenetetracarboxylic dianhydride based molecular devices

Using density functional theory combined with the nonequilibrium Green's function method, spin-dependent transport properties of molecular devices consisting of the 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA) molecule anchored via C and O linkages to zigzag graphene nanoribbon (ZGNR) electrodes were systematically investigated. Calculation results showed that the two connection modes display a good spin transport performance in both parallel (P) and anti-parallel (AP) configurations. Particularly, oxygen connection significantly improves the spin filtration effect. These observations were validated by analyzing spin-resolved transmission spectra, band structures and spatial distribution of molecular orbitals within the bias window. Further comparison of the results of different models indicated that the linkage plays a crucial role in improving the spin transport properties for the proposed NTCDA-ZGNR system, giving them potential applications in high-performance multifunctional spintronic devices.

Retrospective Analysis on 1 900 Cases of Medical Malpractices

Abstract

Objective To study the change trend, distribution characteristics and causes of medical malpractices in 18 years, through retrospective analysis of 1 900 cases of medical malpractices, in order to provide guidance for the precaution and the treatment of medical malpractices. Methods A thousand and nine hundred medical malpractice cases that were accepted by Hunan Xiangya Judical Identification Center from 2000 to 2017 were collected. Statistical analysis on the caseloads, the clients, the department distributions, the levels of the hospital and the causes of medical malpractices, etc were conducted. Results The number of cases commissioned by third-party accreditation agencies for medical fault identification was on the rise; The clients of medical malpractices changed significantly in 18 years. Most of the medical malpractice cases occurred in secondary and tertiary hospitals, significantly more in surgery, obstetrics and gynecology. The occurrence of medical malpractices was related to the doctor's insufficient prediction of the severity of the disease and the possible complications, and failure to fully inform the relevant duty of care, etc. Conclusion China's medical malpractice solutions and medical fault identification procedures are gradually improving. Strengthening the medical malpractice precaution awareness of medical workers in surgery, obstetrics and gynecology will be conducive to resolution of medical malpractices.

First-principles study on screening doped TiO2(B) as an anode material with high conductivity and low lithium transport resistance for lithium-ion batteries

As a promising anode material, TiO₂(B) has attracted much attention in recent years due to its high power and capacity performances. First-principles calculations are performed here to reveal the electronic properties and the transport of lithium (Li) in the bulk TiO₂(B) with and without atomic doping. It is found that a 4-fold coordinated O atom has the lowest formation energy and the smallest bandgap and is the atom that most easily forms an O-vacancy (O_v). In this work, a series of p-type (N, P, As), n-type (F, Cl, Br), and isoelectronic (S, Se, Te) dopants in TiO₂(B) are studied. For n-type dopants, the substitution of the F atom has no significant effect on the electronic structure, which results in the lowest formation energy. This result demonstrates that the F atom can provide high intrinsic stability. Analysis of the insertion process of Li in doped TiO₂(B) shows that N-doping is the most competitive choice because it not only introduces a lower bandgap of TiO₂(B) but it also has the highest binding energy with Li. The advantage of N-doping is derived from the self-compensation effect. Also, three possible transport paths of Li in TiO₂(B) were studied via the CI-NEB method. The results show that the energy barrier of all diffusion paths of F doping is lower than that of pure TiO₂(B), where path 2 along the b-axis channel has the lowest energy (0.32 eV). This study is expected to shed some light on the electronic structures of TiO₂(B) and the transport properties of Li in it.

Inhibition of TRPA1 and IL-6 signal alleviates neuropathic pain following chemotherapeutic bortezomib

Bortezomib (BTZ) is used as a chemotherapeutic agent for the treatment of multiple myeloma. Nevertheless, one of the significant limiting complications of BTZ is painful peripheral neuropathy during BTZ therapy. Thus, in this study we examined signaling pathways of interleukin-6 (IL-6) and transient receptor potential ankyrin 1 (TRPA1) in the sensory nerves responsible for neuropathic pain induced by BTZ and further determined if influencing the pathways can improve neuropathic pain. ELISA and western blot analysis were used to examine the levels of IL-6, and IL-6 receptor (IL-6R), TRPA1 and p38-MAPK and JNK signal in the lumbar dorsal root ganglion. Behavioral test was performed to determine mechanical and cold sensitivity in a rat model. Our results showed that systemic injection of BTZ increased mechanical pain and cold sensitivity as compared with control animals. Data also showed that protein expression of TRPA1 and IL-6R was upregulated in the dorsal root ganglion of BTZ rats and blocking TRPA1 attenuated mechanical and cold sensitivity in control rats and BTZ rats. Notably, the inhibitory effect of blocking TRPA1 was smaller in BTZ rats than that in control rats. In addition, a blockade of IL-6 signal attenuated intracellular p38-MAPK and JNK in the sensory neuron. This also decreased TRPA1 expression and alleviated mechanical hyperalgesia and cold hypersensitivity in BTZ rats. In conclusion, we revealed specific signaling pathways leading to neuropathic pain induced by chemotherapeutic BTZ, including IL-6-TRPA1, suggesting that blocking these signals is beneficial to alleviate neuropathic pain during BTZ intervention.

Facile synthesis of a bismuth nanostructure with enhanced selectivity for electrochemical conversion of CO2 to formate

Electrochemically converting carbon dioxide (CO2) to formate offers a promising approach for energy conversion and storage. Bismuth is believed to be one of the promising candidates for CO2 electroreduction, but the poor selectivity and complexity of synthesis limit its real application on a large scale. In this work, a facile one-step-reduction method was developed to prepare a bismuth nanostructure in aqueous solution. Owing to its enhanced reactive sites and exposed crystal plane, the prepared Bi nanostructure exhibits excellent performance for CO2 electroreduction, which reaches the maximum faradaic efficiency for formate as high as 92% at a potential of -0.9 V versus a reversible hydrogen electrode. Additionally, the large current density and remarkable durability also reveal its high intrinsic CO2 electroreduction activity. The density functional theory calculation confirms that the formation of intermediate *OCHO that finally converts to formate is thermodynamically favorable on Bi high-index planes. We anticipate that such a facile synthesis strategy and excellent electrocatalytic performance of the Bi nanostructure will be easy to scale up, realizing its industrialization applications in CO2 electrochemical conversion.

Cellular and Acellular Assays for Measuring Oxidative Stress Induced by Ambient and Laboratory-Generated Aerosols

INTRODUCTION

Many studies have established associations between exposure to air pollution, or atmospheric particulate matter (PM), and adverse health effects. An increasing array of studies have suggested oxidative stress as a possible mechanism by which PM-induced health effects arise, and as a result, many chemical and cellular assays have been developed to study PM-induced oxidant production. Although significant progress has been made in recent years, there are still many gaps in this area of research that have not been addressed. Many prior studies have focused on the aerosol of primary origin (e.g., the aerosol emitted from combustion engines) although the aerosol formed from the oxidation of volatile species, secondary organic aerosol (SOA), has been shown to be the predominant type of aerosol even in urban areas. Current SOA health studies are limited in number, and as such, the health effects of SOA are poorly characterized. Also, there is a lack of perspective in terms of the relative toxicities of different SOA systems. Additionally, although chemical assays have identified some SOA constituents associated with adverse health endpoints, the applicability of these results to cellular responses has not been well established.

SPECIFIC AIMS

The overall objective of this study was to better understand the oxidative properties of different types and components of PM mixtures (especially SOA) through systematic laboratory chamber experiments and ambient field studies. The study had four specific aims.

1 To develop a cellular assay optimized for measuring reactive oxygen and nitrogen species (ROS/RNS) production resulting from PM exposure and to identify a robust parameter that could represent ROS/RNS levels for comparison with different endpoints.

2 To identify ambient PM components associated with ROS/RNS production and evaluate whether results from chemical assays represented cellular responses in terms of ROS/RNS production.

3 To investigate and provide perspective on the relative toxicities of SOA formed from common biogenic and anthropogenic precursors under different conditions (e.g., humidity, nitrogen oxides [NOx], and redox-active metals) and identify bulk aerosol properties associated with cellular responses.

4 To investigate the effects of photochemical aging on aerosol toxicity.

METHODS

Ambient PM samples were collected from urban and rural sites in the greater Atlanta area as part of the Southeastern Center for Air Pollution and Epidemiology (SCAPE) study between June 2012 and October 2013. The concentrations of water-soluble species (e.g., water-soluble organic carbon [WSOC], brown carbon [Br C], and metals) were characterized using a variety of instruments. Samples for this study were chosen to span the observed range of dithiothreitol (DTT) activities.

Laboratory studies were conducted in the Georgia Tech Environmental Chamber (GTEC) facility in order to generate SOA under well-controlled photooxidation conditions. Precursors of biogenic origin (isoprene, α-pinene, and β-caryophyllene) and anthropogenic origin (pentadecane, m-xylene, and naphthalene) were oxidized under various formation conditions (dry vs. humid, NOx, and ammonium sulfate vs. iron sulfate seed particles) to produce SOA of differing chemical composition and mass loading. For the naphthalene system, a series of experiments were conducted with different initial hydrocarbon concentrations to produce aerosols with various degree of oxidation. A suite of instruments was utilized to monitor gas- and particle-phase species. Bulk aerosol properties (e.g., O:C, H:C, and N:C ratios) were measured using a high-resolution time-of-flight aerosol mass spectrometer. Filter samples were collected for chemical oxidative potential and cellular measurements. For the naphthalene system, multiple filter samples were collected over the course of a single experiment to collect aerosols of different photochemical aging.

For all filter samples, chemical oxidative potentials were determined for water-soluble extracts using a semiautomated DTT assay system. Murine alveolar macrophages and neonatal rat ventricular myocytes were also exposed to PM samples extracted in cell culture medium to investigate cellular responses. ROS/RNS production was detected using the intracellular ROS/RNS probe, carboxy-2',7'-dichlorodihydrofluorescein diacetate (carboxy-H2DCFA), whereas cellular metabolic activity was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Finally, cytokine production, that is, secreted levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), were measured post-exposure using an enzyme-linked immunosorbent assay (ELISA). To identify PM constituents associated with oxidative properties, linear regressions between oxidative properties (cellular responses or DTT activity) and aerosol composition (metals, elemental ratios, etc.) were evaluated using Pearson's correlation coefficient, where the significance was determined using multiple imputation and evaluated using a 95% confidence interval.

RESULTS

We optimized several parameters for the ROS/RNS assay, including cell density (2 × 104 cells/well for macrophages and 3.33 × 104 cells/well for cardiomyocytes), probe concentration (10 µM), and sample incubation time (24 hours). Results from both ambient and laboratory-generated aerosols demonstrate that ROS/RNS production was highly dose-dependent and nonlinear with respect to PM dose. Of the dose-response metrics investigated in this study (maximum response, dose at which the response is 10% above the baseline [threshold], dose at which 50% of the response is attained [EC50], rate at which the maximum response is attained [Hill slope], and area under the dose-response curve [AUC]), we found that the AUC was the most robust parameter whose informativeness did not depend on dose range.

A positive, significant correlation was observed between ROS/RNS production as represented by AUC and chemical oxidative potential as measured by DTT for ambient samples collected in summer. Conversely, a relatively constant AUC was observed for ambient samples collected in winter regardless of the corresponding DTT activity. We also identified several PM constituents (WSOC, BrC, iron, and titanium) that were significantly correlated with AUC for summer samples. The strong correlation between organic species and ROS/RNS production highlights a need to understand the contribution of organic aerosols to PM-induced health effects. No significant correlations were observed for other ROS/RNS metrics or PM constituents, and no spatial trends were observed.

For laboratory-generated aerosol, precursor identity influenced oxidative potentials significantly, with isoprene and naphthalene SOA having the lowest and highest DTT activities, respectively. Both precursor identity and formation condition significantly influenced inflammatory responses induced by SOA exposure, and several response patterns were identified for SOA precursors whose photooxidation products share similar carbon-chain length and functionalities. The presence of iron sulfate seed particles did not have an apparent effect on oxidative potentials; however, a higher level of ROS/RNS production was observed for all SOA formed in the presence of iron sulfate compared with ammonium sulfate. We also identified a significant positive correlation between ROS/RNS production and average carbon oxidation state, a bulk aerosol property. It may therefore be possible to roughly estimate ROS/RNS production using this property, which is readily obtainable. This correlation may have significant implications as aerosols have an atmospheric lifetime of a week, during which average carbon oxidation state increases because of atmospheric photochemical aging. Our results suggest that aerosols might become more toxic as they age in the atmosphere. Finally, in the context of ambient samples, laboratory-generated SOA induced comparable or higher levels of ROS/RNS. Oxidative potentials for all laboratory SOA systems, with the exception of naphthalene (which was higher), were all comparable with oxidative potentials observed in ambient samples.