Diverse perspectives on social determinants of multicultural adolescents: A focus group study

Background

As Korea transforms into a multicultural society, social vulnerability of the multicultural adolescents (MAs) puts them at risk for poor health and health disparities. However, there is shortage of evidence on social determinants of health (SDH), which refers to the circumstances of people from birth to death, which affects their health outcomes, for MAs. Thus, this study aims to explore the SDH of MAs from diverse stakeholders’ perspectives.

Methods

This qualitative study comprised 17 focus group interviews with 99 participants (MAs, peers, parents, teachers, neighbors, and community leaders), conducted from June to September 2020. The directed content analysis was conducted using the Minority Health and Health Disparities Research Framework with a high rigor level based on the four criteria of Lincoln and Guba’s trustworthiness.

Results

The participants addressed SDH of MAs in five domains: biological (vulnerability and mechanism); behavioral (health behavior, family/school/peer functioning, and policies and laws); physical/built environment (school/community environment); sociocultural environment (MAs'/parental sociodemographic, language proficiency, MAs'/parental acculturation, social network, and response to/interpersonal/local/societal structural discrimination); and health care system (insurance coverage, MAs'/parental health literacy, availability of services, and health care policies). However, limited SDH in biological and physical/built environment domains were identified.

Conclusions

SDH in sociocultural environment domain and interpersonal influence level were the most commonly addressed. Interpersonal discrimination of both MAs and parents were found to be the most important SDH. These findings suggest that future programs to enhance MAs’ health may be targeted toward reducing discrimination and involving their parents.

Key messages

• Sociocultural environment was found to be the most salient SDH domain to affect MAs’ health.

• SDH of MAs are linked to discrimination and their parents’ sociocultural aspects such as acculturation.

Deep-Learning-Based Stroke Screening Using Skeleton Data from Neurological Examination Videos

According to the Korea Institute for Health and Social Affairs, in 2017, the elderly, aged 65 or older, had an average of 2.7 chronic diseases per person. The concern for the medical welfare of the elderly is increasing due to a low birth rate, an aging population, and the lack of medical personnel. The demand for services that take user age, cognitive capacity, and difficulty into account is rising. As a result, there is an increased demand for smart healthcare systems that can lower hospital admissions and offer patients individualized care. This has motivated us to develop an AI system that can easily screen and manage neurological diseases through videos. As neurological diseases can be diagnosed by visual analysis to some extent, in this study, we set out to estimate the possibility of a person having a neurological disease from videos. Among neurological diseases, we focus on stroke because it is a common condition in the elderly population and results in high mortality and morbidity worldwide. The proposed method consists of three steps: (1) transforming neurological examination videos into landmark data, (2) converting the landmark data into recurrence plots, and (3) estimating the possibility of a stroke using deep neural networks. Major features, such as the hand, face, pupil, and body movements of a person are extracted from test videos taken under several neurological examination protocols using deep-learning-based landmark extractors. Sequences of these landmark data are then converted into recurrence plots, which can be interpreted as images. These images can be fed into convolutional neural networks to classify stroke using feature-fusion techniques. A case study of the application of a disease screening test to assess the capability of the proposed method is presented.

Trends in management of cardiovascular risk factors in young adults who go on to develop coronary artery disease

Background

Rates of premature coronary artery disease (CAD) have remained stagnant in many countries in the past two decades. While guidelines on cardiovascular prevention are evolving to improve risk assessment, more data are needed to evaluate changes in risk management in younger patients with high cardiovascular risk.

Purpose

To investigate the trends in pre-presentation prevalence and management of major cardiovascular risk factors (CVRFs) and predictors of initiation of lipid-lowering therapy (LLT) in patients with premature coronary artery disease.

Methods

In this retrospective cohort study, we identified women <55 years old and men <50 years old who presented with obstructive CAD (stenosis >50% or history of coronary revascularization) between 2000 and 2017. Data were collected from administrative databases and provincial cardiac information system and included demographics, all outpatient visits, hospitalizations, pharmacy dispenses in the period of 3 years prior to CAD, presentation characteristics, and results of invasive coronary angiography.

Results

In total, 14,470 patients (29.7% females) met the study criteria. During the study period, prevalence decreased for dyslipidemia and smoking and increased for hypertension, diabetes and obesity (Figure 1). Over 96.5% of patients were eligible for lipid screening 3 years prior to presentation with CAD, 93.5% had visits with primary care physicians, and 57.4% had visits with specialist physicians. Only 20.5% received LLT, with rates rising from 19% in the year 2000 to 24% in 2017 (p=0.023). Additionally, 38.1% of patients received medical treatment for other CVRFs. Figure 2 presents risk management and rates of LLT initiation in patients with five major CVRFs. In multivariable logistic regression analysis, LLT was more likely in patients with diabetes (odds ratio [OR] 3.04, 95% CI 2.74–3.36), hypertension (OR 1.44, 95% CI 1.30–1.58), chronic kidney disease (OR 1.79, 95% CI 1.44–2.23), and depression (OR 1.25, 95% CI 1.11–1.40). Later year of presentation (OR 1.04, 95% CI 1.03–1.05), older age at presentation (OR 1.03, 95% CI 1.02–1.04) and residing in urban areas vs rural (OR 1.36, 95% CI 1.16–1.58) were also positively associated with LLT. Male sex (OR 0.88, 95% CI 0.78–0.98) and smoking (OR 0.68, 95% CI 0.62–0.76) were associated with lower likelihood of treatment. Obesity, hypothyroidism, chronic inflammatory conditions, and malignancies were not significantly associated with LLT.

Conclusion

Despite the rising prevalence of CVRFs, high eligibility for lipid screening, and availability of care, rates of LLT initiation in patients who go on to develop premature CAD remain very low, representing a major missed opportunity for cardiovascular disease prevention. Many of the major CVRFs and risk enhancers endorsed in current guidelines were not associated with treatment initiation, suggesting that new approaches may be required to increase appropriate use LLT in these patients.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): St. Pauls Hospital Foundation, Vancouver, BC, CanadaVancouver General Hospital Foundation, Vancouver, BC, Canada

Association of usual walking with mortality in oldest old adults aged 85 years and older: a nationwide senior cohort study

Background

Current guidelines recommend moderate to vigorous intensity physical activity (MVPA) for health benefit in adults. However, it is difficult to meet the recommended minimum MVPA in “oldest old” aged over 85. Although walking is simple and easy exercise for oldest old, research on the association between walking and mortality in oldest old are lacking.

Purpose

To investigate the association between walking and the risk of all-cause and cardiovascular mortality among older adults aged 85 years and older.

Methods

7047 participants aged 85 or older underwent the Korean National Health Screening Program, including self-administered questionnaire for physical activity. Reported frequency per week of walking for at least 30 minutes increment was used to classify hours of walking per week. We computed multivariable-adjusted hazard ratios for walking and mutually adjusted for MVPA in relation to all-cause and cardiovascular mortality.

Results

The proportions of participants who engaged in walking, moderate- and vigorous-intensity physical activity were 42.5% (2996/7047), 14.7% (1037/7047) and 11.0% (773/7047), respectively. Only 7.6% (538/7047) of participants met the guidelines recommended minimum MVPA. Compared to inactive individuals, those who walked at least 1 hour per week had lower all-cause (HR 0.60 [95% CI, 0.50–0.74]) and cardiovascular mortality risk (HR 0.61 [95% CI, 0.42–0.89]). Walking 1 hour per week was still significant associated with reduction of risk for all-cause (HR 0.50 [95% CI, 0.40–0.61]) and cardiovascular mortality (HR 0.46 [95% CI, 0.30–0.70]) among participants who reported only walking without any MVPA.

Conclusions

1 hour a week of walking might be of benefit for all-cause and cardiovascular mortality in aged over 85 years, even without MVPA. Promoting walking may be a way to help oldest old avoid inactivity and encourage an active lifestyle for all-cause and cardiovascular mortality risk reduction.

Funding Acknowledgement

Type of funding sources: None.

Pathogenic variants damage cell compositions and single cell transcription in cardiomyopathies

 

Pathogenic variants in genes that cause dilated (DCM) and arrhythmogenic cardiomyopathies (ACM) convey high risks for the development of heart failure (HF) through unknown mechanisms. Using single nucleus RNA sequencing (snRNAseq), we characterized the transcriptome of 880,000 nuclei from 18 control and 61 failing, non-ischemic human hearts with pathogenic variants in DCM and ACM genes or idiopathic disease. We performed genotype-stratified analyses of the ventricular cell lineages and transcriptional states. The resultant DCM and ACM ventricular cell atlas demonstrated distinct right and left ventricular responses, highlighting genotype-associated pathways, intercellular interactions, and differential gene expression at single cell resolution. Together these data illuminate both shared and distinct cellular and molecular architectures of human HF and suggest novel candidate therapeutic targets.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Chan Zuckerberg FoundationLeducq Foundation

Alleviation of AF related symptoms following acute conversion of recent-onset, symptomatic atrial fibrillation to sinus rhythm with flecainide acetate oral inhalation solution

Introduction

Pharmacological restoration of sinus rhythm (SR) in patients with symptomatic atrial fibrillation (AF) is expected to be accompanied by prompt alleviation of symptoms to avoid the need for electrical cardioversion (ECV) and/or hospitalization. The feasibility and safety of acute cardioversion of recent-onset (≤48 hours) symptomatic AF to SR with flecainide acetate oral inhalation (FlecIH) solution was shown in the Phase 2, open-label INSTANT trial. We examined symptoms, heart rate, time to discharge and need for ECV reported among patients in the INSTANT trial whose AF was successfully converted to SR (“conversion group”; N=25) versus those whose AF did not convert to SR (“no conversion group”; N=29).

Methods

Conversion success was determined using 12-lead Holter monitoring during a 90-minute observation period. Patients in the no conversion group were offered alternative treatment per the investigator discretion. Symptoms, vital signs, time to discharge, and the need for ECV were evaluated through Day 5.

Results

Data from 54 patients (33.3% female) with a mean age of 62.1 years and a mean BMI of 26.8 kg/m2 were analyzed. All patients reported at least one AF-related symptoms at baseline (palpitations=85%; dizziness=35%; shortness of breath=37%; chest discomfort=39%) and 83.3% presented with AF symptoms ≤24 hours in duration. At 90 minutes, 80.0% of the conversion group were asymptomatic compared to 37.9% of the no conversion group (p<0.001). Mean (SD) ventricular rate at 90 minutes was 70.6 (12.5) bpm in the conversion group compared to 100.4 (29.4) bpm in the no conversion group (p<0.001). Median time to discharge was 2.3 (IQR: 0.75) hours for the conversion group compared to 3.6 (IQR: 1.02) hours for the no conversion group (p=0.001). By Day 5, 23 (79.3%) patients in the no conversion group had undergone ECV; no patients in the conversion group experienced AF recurrence by Day 5 (0% required ECV; p<0.001).

Conclusions

Conversion of recent onset AF to SR with inhaled flecainide was associated with a reduction in symptoms, normalization of heart rate, rapid hospital discharge and avoidance of ECV during a 5-day follow-up period.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): InCarda Therapeutics

The efficacy of immune checkpoint inhibitors in elderly patients: a meta-analysis and meta-regression

Background

Immune checkpoint inhibitor (ICI) therapy has improved patient survival in advanced cancers; however, the efficacy of ICIs in elderly patients is still elusive. This study assessed the efficacy of ICIs in elderly patients with advanced cancer in terms of overall survival (OS) and progression-free survival (PFS).

Materials and methods

We carried out a systematic review and identified 30 head-to-head phase II/III randomized controlled trials that compared immunotherapy with the standard of care in advanced solid tumor patients. The data on patients younger or over 65 years of age were indexed from PubMed-Medline, Embase, and Scopus and obtained for meta-analysis. The subgroup analyses were stratified by primary tumor type, line of treatment, or type of immunotherapy, and a meta-regression analysis was carried out after adjusting for all other variables.

Results

The study included 17 476 patients, comprising 58% (10 119) younger (<65 years old) and 42% (7357) elderly (≥65 years old) patients. The hazard ratio (HR) for OS was 0.77 [95% confidence interval (CI) 0.70-0.85] and 0.77 (95% CI 0.70-0.85) in the younger and elderly groups, respectively, suggesting similar efficacies of ICIs in these two age groups. The subgroup analyses revealed no significant relationship between age and treatment outcomes, except for the PFS benefit in younger patients with melanoma than in elderly patients (HR 0.44 in younger patients versus 0.65 in elderly patients, P = 0.04). These results were further supported by meta-regression analysis, which showed no statistically significant difference in OS (P = 0.954) and PFS (P = 0.555) between the two age groups.

Conclusions

The findings suggest that age-associated impairments of the immune system did not affect the efficacy of ICIs in elderly patients compared to younger patients. Therefore, the choice of ICIs for elderly patients can be considered, regardless of chronological age.

•

We evaluated the efficacy of ICI in 17 476 patients, comprising 58% younger and 42% elderly patients.

•

Meta-analysis resulted in the comparable efficacy of ICI between younger and older age groups.

•

Further, meta-regression analysis showed no significant difference in OS and PFS.

•

Our study suggests that chronological age does not lead to immunosenescence in response to ICI in immune-oncology.

Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion.

O049 FRAX score assessment of long term follow up thyroid cancer patients

Introduction

Thyroid stimulating hormone (TSH) suppression with Levothyroxine (LT4) following thyroid cancer surgery is recommended in some patients under long term follow up. However, LT4 may cause reduced bone mineral density. We aimed to assess patients in our long-term thyroid cancer follow up clinic for risk to bone health.

Methods

We conducted a review of all patients in the thyroid cancer follow-up clinic and calculation of FRAX score for those that are &gt;40 years old who are followed up in the Endocrine Surgical Service of NUH. Subsequently patients were categorised into risk groups according to the Osteoporosis Group Guideline (2017) and managed accordingly.

Results

78 patients were identified and had ongoing follow up. 23 patients were excluded as they were &lt;40 years old. 10 patients did not want to participate in the study. 45 patients were assessed with the FRAX score. There were 31 female and 14 male patients, mean age 60.8 (±12.3) years. The mean follow up was 75.0 (±78.9) months. 11% (five patients) were found to require treatment for Osteoporosis without a bone mineral density (BMD) scan, 38% (17 patients) were recommended to assess their BMD, 4% had borderline risk to measure BMD, and 47% required lifestyle and dietary modification.

Conclusion

Thyroid cancer patients aged 40 and above represent a cohort in whom osteoporosis is a substantial risk and warrant assessment with a FRAX score.

Take-home message

Thyroid cancer patients aged 40 and above represent a cohort in whom osteoporosis is a substantial risk and warrant assessment with a FRAX score.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

The natural history of low-risk non-muscle-invasive bladder cancer: a collaborative multi-centre study

BACKGROUND

International guidelines vary in terms of their definition and recommendation for management of low-risk non-muscle-invasive bladder cancer (LRNMIBC). The ideal management for this large subset of bladder cancer patient remains unclear.

OBJECTIVE

To evaluate long-term outcomes of patients with LRNMIBC. As a secondary objective, to assess for intergroup heterogeneity in disease-specific outcomes between G1 and G2LG diseases.

METHODS

A multi-centre, retrospective study of patients who met the 2015 NICE definition of LRNMIBC. Timeline of diagnosis ranged from 01/01/2012 to 30/06/2016.

RESULTS

A total 390 patients had available follow-up data (G1: 142, G2LG: 249). Over a median follow-up time of 36 months (IQR 25-50), 29.2% of the patients developed a recurrence. G2LG patients were statistically more likely to develop a recurrence (G1: 26.8%, G2LG: 33.7%, p < 0.05). 51.8% of recurrences occurred after 1 year of surveillance. Progression to high-grade disease occurred in 1.8% (n = 7, G1: 3, G2LG: 4) and a further 1.0% (n = 4, G1:3, G2LG: 1) of patients developed muscle-invasive bladder cancer (MIBC).

CONCLUSION

The majority of recurrences occurred after 1 year of surveillance. The risk of disease progression was low; however, this was observed in a cohort of patients with regular cystoscopic follow-up. The risk may be higher if patients were pre-maturely discharged. If a 5-year surveillance programme were to be followed, 96.5% of recurrences would be captured. Lastly, there appears to be intergroup heterogeneity within LRNMIBC with G2LG patients having a statistically higher risk of recurrence compared to G1.

POS0641 A RANDOMISED PHASE I PHARMACOKINETIC STUDY COMPARING HIGH-CONCENTRATION, LOW-VOLUME, AND CITRATE-FREE SB5 (40 MG/0.4 ML) WITH PRIOR SB5 FORMULATION, AND ADALIMUMAB BIOSIMILAR, IN HEALTHY MALE SUBJECTS

Background

SB5, an adalimumab (ADL) biosimilar, was developed in a low-concentration (40 mg/0.8 mL, SB5-LC) aligned with the reference ADL product. Pharmacokinetics (PK) equivalence of SB5 and reference ADL was demonstrated in a Phase I study conducted in healthy subjects1. Equivalent efficacy and comparable safety between 40 mg/0.8 mL SB5 and 40 mg/0.8 mL reference ADL were demonstrated in a Phase III study conducted in patients with rheumatoid arthritis2. High-concentration, low-volume, citrate-free SB5 (40 mg/0.4 mL, SB5-HC) has been developed as a part of life cycle management in line with the reference ADL formulation.

Objectives

To compare the PK, safety, and tolerability of the newly developed SB5-HC (40 mg/0.4 mL) to prior SB5-LC (40 mg/0.8 mL) in healthy male subjects.

Methods

This study was a randomised, single-blind, two-arm, parallel group, single-dose study in healthy male subjects. Subjects were randomised in a ratio of 1:1 to receive a single dose of either SB5-HC or SB5-LC by subcutaneous injection on Day 1 and then observed for 57 days during which the PK, safety, and immunogenicity were evaluated. The serum concentration of ADL was measured using an enzyme-linked immunosorbent assay. The primary PK parameters were area under the concentration-time curve from time zero to infinity (AUCinf) and maximum serum concentration (Cmax). Equivalence for the primary PK parameters was to be concluded if the 90% confidence intervals (CIs) for the ratio of geometric least squares means (LSMeans) of the treatment groups compared were completely contained within the pre-defined equivalence margin of 0.80 to 1.25 using an analysis of variance.

Results

Of 188 randomised subjects, 187 subjects were analysed as PK Analysis Set (PKS) (n=93 in SB5-HC and n=94 in SB5-LC). One subject was excluded from the PKS in SB5-HC group (major protocol deviation for not being withdrawn in the event of confirmed COVID-19). The geometric LSMeans ratios for the comparison of SB5-HC and SB5-LC for AUCinf and Cmax were 0.920 and 0.984, respectively, and the corresponding 90% CIs were within the pre-defined equivalence margin of 0.80 to 1.25 (Table 1), indicating the two treatment groups are bioequivalent. There were no deaths, serious adverse events or discontinuation of the study due to treatment-emergent adverse events (TEAEs) during the study. The proportions of subjects who experienced TEAEs were comparable between the two treatment groups (44.7% in SB5-HC vs 51.1% in SB5-LC). The most frequent TEAEs were headache (10.6% in SB5-HC vs 12.8% in SB5-LC).

Table 1.

Comparison of Primary PK Parameters between the Treatments

PK ParameterTreatmentGeometric LSMeanRatio90% CIAUCinf (h·μg/mL)SB5-HC2616.10.9200.8262; 1.0239SB5-LC2844.3Cmax (μg/mL)SB5-HC4.10.9840.9126; 1.0604SB5-LC4.1

Conclusion

This study demonstrated PK equivalence between SB5-HC and SB5-LC in healthy subjects. Both SB5-HC and SB5-LC were generally well tolerated with similar safety profiles.

References

[1]Shin D et al. J Clin Pharm Ther. 2017 Dec;42(6):672-678.

[2]Weinblatt ME et al. Arthritis Rheumatol. 2018 Jun;70(6):832-840.

Disclosure of Interests

None declared

POS0451 DEFICIENCY OF PPM1A IN MACROPHAGE AGGRAVATES PRISTANE-INDUCED LUPUS-LIKE DISEASE

Background

Protein phosphatase Mg2+/Mn2+-dependent 1A (PPM1A) is a phosphatase which regulates various intracellular cell signaling pathways including inflammation. We previously suggested that the inflammatory signal decreased the PPM1A protein level in macrophage and this reduction had correlation with the chronic inflammatory bone disease, implying the possible role of PPM1A in inflammatory responses of macrophage.

Objectives

In this study, we aim to elucidate the potential role of PPM1A in macrophage to regulate inflammatory response during the disease progression of systemic lupus erythematosus.

Methods

We generated macrophage-specific conditional gene-knockout (PPM1Afl/fl;LysM-Cre) mice and developed a lupus-like disease with immune complex glomerulonephritis in these PPM1Afl/fl;LysM-Cre mice by intraperitoneal pristane injection. Mouse serum was collected every 4 weeks after pristane injection. Serum anti-dsDNA IgG, anti-ssDNA IgG, interleukin-17 (IL-17) and tumor necrosis factor-α (TNF-α) was quantified by ELISA. After 41 weeks from pristane injection, histological changes in the kidney, spleen, and lung tissues were observed. To analyze M1/M2 polarization in vitro, LysM-Cre and PPM1Afl/fl;LysM-Cre mouse bone marrow-derived macrophages were cultured with lipopolysaccharide (LPS)/interferon-γ (IFN-γ) or interleukin-4 (IL-4) to check M1 or M2 related genes.

Results

We found that macrophages of PPM1Afl/fl;LysM-Cre mice displayed different gene expression with LPS stimulation especially in M1/M2 related genes through the RNA-seq analysis and showed a decrease in both M1 and M2 polarization induced by LPS/IFN-γ or IL-4 stimulation. Notably, we found that PPM1Afl/fl;LysM-Cre mice with pristane injection showed a significant increase of anti-ssDNA IgG compared to LysM-Cre mice. PPM1Afl/fl;LysM-Cre mice showed severe lupus-like phenotypes such as global glomerular enlargement indicated by endocapillary proliferation and glomerular cellularity in kidney and lung inflammation accompanied by fibrosis, compared to LysM-Cre mouse by pristane injection. Together, serum IL-17 and TNF-α, which are proinflammatory cytokines, were increased in PPM1Afl/fl;LysM-Cre after pristane injection. These results indicate that PPM1A depletion in macrophage deteriorates inflammation and contributes to the tissue damage in a lupus-like disease.

Conclusion

Our findings suggest that the deficiency of PPM1A in macrophages impairs M1/M2 macrophage polarization leading to an immune imbalance in lupus-like disease model, providing a potential link between the loss of function of PPM1A in macrophages and its molecular target for treatment of systemic lupus erythematosus.

References

[1]Kwon, O. C., Choi, B., Lee, E. J., Park, J. E., Lee, E. J., Kim, E. Y., Kim, S. M., Shin, M. K., Kim, T. H., Hong, S., Lee, C. K., Yoo, B., Robinson, W. H., Kim, Y. G., & Chang, E. J. (2020). Negative Regulation of Osteoclast Commitment by Intracellular Protein Phosphatase Magnesium-Dependent 1A. Arthritis & rheumatology (Hoboken, N.J.), 72(5), 750–760. https://doi.org/10.1002/art.41180

[2]Smith, S. R., Schaaf, K., Rajabalee, N., Wagner, F., Duverger, A., Kutsch, O., & Sun, J. (2018). The phosphatase PPM1A controls monocyte-to-macrophage differentiation. Scientific reports, 8(1), 902. https://doi.org/10.1038/s41598-017-18832-7

Disclosure of Interests

None declared.