[Drug-resistant gene polymorphisms in Plasmodium falciparum isolated from Bioko Island, Equatorial Guinea in 2018 and 2019]

OBJECTIVE

To investigate the genetic polymorphisms of Plasmodium falciparum multidrug resistance protein 1 (PfMDR1), chloroquine resistance transporter (PfCRT) and Kelch 13 (PfK13) genes in Bioko Island, Equatorial Guinea, so as to provide insights into the development of the malaria control strategy in local areas.

METHODS

A total of 85 peripheral blood samples were collected from patients with Plasmodium falciparum infections in Bioko Island, Equatorial Guinea in 2018 and 2019, and genomic DNA was extracted. The PfMDR1, PfCRT and PfK13 genes were amplified using a nested PCR assay. The amplification products were sequenced, and the gene sequences were aligned.

RESULTS

There were no mutations associated with artemisinin resistance in PfK13 gene in Bioko Island, Equatorial Guinea, while drug-resistant mutations were detected in PfMDR1 and PfCRT genes, and the proportions of PfMDR1_N86Y, PfMDR1_Y184F and PfCRT_K76T mutations were 35.29% (30/85), 72.94% (62/85) and 24.71% (21/85), respectively.

CONCLUSIONS

There are mutations in PfMDR1, PfCRT and PfK13 genes in P. falciparum isolates from Bioko Island, Equatorial Guinea.

P–412 Low serum hCG levels adjusted for the hCG trigger dose in fresh cycles may be associated with a poor clinical pregnancy rate of FET cycles

Study question

Is there any association between serum human chorionic gonadotropin (hCG) levels after trigger at previous fresh cycles and pregnancy outcomes of frozen-thawed embryo transfer (FET) cycles?

Summary answer

Low adjusted serum hCG level after hCG trigger at fresh cycles is negatively associated with clinical pregnancy rates (CPR) of hormone replacement treatment-FET (HRT-FET). What is known already: Literature showed that low serum hCG levels after the same dose of hCG trigger was associated with reduced pregnancy outcomes of the fresh cycles. However, the relationship between hCG levels after trigger at fresh cycles and pregnancy outcomes of FET cycles remains unknown.

Study design, size, duration

This matched retrospective study was conducted at a Reproductive Medicine Center between 2016 and 2018. Subjects performing HRT-FET cycles, whose previous fresh cycles used a bolus of hCG alone or a bolus of GnRHa combined with hCG for trigger were included. A total of 186 HRT-FET cycles with complete data was included for the final analysis.

Participants/materials, setting, methods

The study population was grouped into women with intramuscular injection of hCG prior to secretory transformation (hCG group, n = 93) and a comparison group (control group, n = 93) of women without hCG addition matched for patients’ age and duration of infertility. At the previous fresh cycles, serum hCG levels were measured 12 hours later after hCG trigger (defined as the “hCG+12 h” timepoint), and were adjusted for doses (defined as adjusted hCG levels). Main results and the role of chance: For patients achieving clinical pregnancy, the adjusted hCG level significantly increased (P < 0.05). Meanwhile, the ROC curve also showed a significantly predictive value of adjusted serum hCG levels at the “hCG+12 h” timepoint for CPR in HRT- FET cycles (AUC=0.626, 95%CI: 0.512–0.740) and the optimal hCG threshold proposed by ROC for CPR was 46.31 mIU/mL with sensitivity of 71.4% and specificity of 56.9%. For all patients, the CPR in hCG group was significantly higher than that in control group (61.3% vs. 44.1%). Furthermore, all cycles were then divided into four groups based on the injection of hCG prior to secretory transformation in HRT-FET cycles and this cut-off value of hCG levels at the “hCG+12 h” timepoint. For patients with adjusted hCG levels ≤46.31 mIU/mL, the CPR was significantly improved in hCG group compared with control group (61.1% vs. 29.3%). But for patients with adjusted hCG levels >46.31 mIU/mL, no statistically significant difference was observed between the hCG and control group (61.4% vs. 55.8%).

Limitations, reasons for caution

Although the results achieved statistically significant, the sample size was relatively small, which limits our ability to draw a definitive conclusion. The reason of the small sample size may be that to reduce the risk of OHSS, doctors would give preference to trigger with GnRH agonist in our center.

Wider implications of the findings: Adjusted serum hCG levels might represent a potential factor to guide adequate support in the subsequent HRT-FET cycles. Meanwhile, for patients with low adjusted serum hCG levels, intramuscular hCG injection prior to secretory transformation may be a good compensation way to rescue pregnancy impair in the subsequent HRT-FET cycles.

Trial registration number

N/A.

An epidermal patch for the simultaneous monitoring of haemodynamic and metabolic biomarkers

Monitoring the effects of daily activities on the physiological responses of the body calls for wearable devices that can simultaneously track metabolic and haemodynamic parameters. Here we describe a non-invasive skin-worn device for the simultaneous monitoring of blood pressure and heart rate via ultrasonic transducers and of multiple biomarkers via electrochemical sensors. We optimized the integrated device so that it provides mechanical resiliency and flexibility while conforming to curved skin surfaces, and to ensure reliable sensing of glucose in interstitial fluid and of lactate, caffeine and alcohol in sweat, without crosstalk between the individual sensors. In human volunteers, the device captured physiological effects of food intake and exercise, in particular the production of glucose after food digestion, the consumption of glucose via glycolysis, and increases in blood pressure and heart rate compensating for oxygen depletion and lactate generation. Continuous and simultaneous acoustic and electrochemical sensing via integrated wearable devices should enrich the understanding of the body's response to daily activities, and could facilitate the early prediction of abnormal physiological changes.

[Study of B10 cells in the pathogenesis of the interaction between chronic obstructive pulmonary disease and periodontal disease]

Objective: To determine the ratio of ingerleukin(IL)-10 secreting regulatory B cells (B10 cells) and the levels of IL-10 in peripheral blood of periodontitis patients with or without chronic obstructive pulmonary disease (COPD), and to explore the function of B10 cells in the pathogenesis of the interaction between COPD and periodontitis. Methods: Forty-five periodontitis patients and healthy people were recruited and divided into three groups: COPD group, COPD+periodontitis group and health controls with 15 people in each group. Peripheral blood samples were collected to determine the B10 population. Another group of 93 periodontitis patients and healthy people were also collected and divided into the same 3 groups with 31 people in each group. Peripheral blood samples were collected to determine the cytokine IL-10. Results: After stimulation with lipopolysaccharide (LPS)+phorbol-12-myristate13-acetate+ionomycin+brefeldin A (PIB) for 5 h, the ratio of B10 in COPD+periodontitis group [(0.44±0.11)%] was significantly lower than that in the control group [(0.63±0.14)%] and periodontitis group [(0.62±0.13)%] (P<0.01), respectively. The ratio of B10 cells showed no significant difference between periodontitis group and healthy control group (P>0.05). After stimulation with LPS+PIB for 48 h, the ratio of B10 cells in COPD+periodontitis group [(7.59±1.33)%] was significantly lower than that in the periodontitis group [(10.14±2.02)%] and the healthy controls [(11.80±1.71)%] (P<0.01), respectively. The ratio of B10 cells in periodontitis group was significantly lower than that in the healthy controls (P<0.05). The levels of IL-10 in periodontitis group [(2.55±0.61) ng/L] and COPD+periodontitis group [(1.95±0.45) ng/L] were significantly lower than that in the control group [(3.96±1.15) ng/L] (P<0.01) respectively. Moreover, the level of IL-10 in COPD+periodontitis group was significantly lower than that in the periodontitis group (P<0.01). Conclusions: The dysfunction of immune system caused by the decreased proportion of B10 cells might be involved in the pathological process of COPD promoted by periodontitis.

[Protein Disulfide Bonds Detected by Tagging with High Molecular Weight Maleimide Derivative]

Disulfide bridges are essential for maintaining the structure and function of proteins. Traditionally, studies of the disulfide bonds require expensive equipment and high purity of the protein sample, therefore, the development of simpler techniques is warranted. Here, were present a novel protocol for the detection of disulfide bonds in proteins, which is based on the labeling reduced disulfide bridges with a high molecular weight (HMW) maleimide derivative. After irreversible blocking of free thiol groups of proteins, the labeling of new thiols released from disulfide bridges with a high-molecular-weight (HMW) maleimide derivative is performed. To confirm localization of cysteines involved in the formation of disulfide bonds, cysteine mutagenesis was conducted. For validation, aquaporin 5 (AQP5) and transient receptor potential cation channel subfamily V member 4 (TRPV4) proteins were tagged with FLAG (DYKDDDDK) on N-termini. Increase in MW of the target proteins from immunoblot indicated the presence of disulfide bonds. No bands with increased MW were detected in AQP5, while TPRV4 cysteines at disulfide bridges-constituting positions 639, 645, 652, 660, 770 were detected and confirmed by cysteine mutagenesis. These data indicate that the proposed technique is feasible and effective for the detection of protein disulfide bonds.

AB0251 INCREASED ACCUMULATION OF ERYTHROCYTE METHOTREXATE POLYGLUTAMATES DURING EARLY PHASE SUBCUTANEOUS VERSUS ORAL METHOTREXATE TREATMENT OF RHEUMATOID ARTHRITIS PATIENTS

Background:

Optimal dosing of methotrexate (MTX) for individual rheumatoid arthritis (RA) patients to achieve adequate disease control is an ongoing challenge. Assessment of erythrocyte MTX-polyglutamates (PGs) levels has been employed as a tool to monitor clinical response of RA patients in the first 3-12 months of treatment and MTX-PG2-4 and total MTX-PGs were associated with a lower DAS28 over 9 months.1 However, data from earlier time points, MTX-PG6 and per route of administration are unavailable.

Objectives:

To investigate the pharmacokinetics and -dynamics of erythrocyte MTX-PG accumulation in RA patients receiving oral or subcutaneous MTX in the early phase (1, 2, and 3 months) of MTX treatment initiation.

Methods:

In a clinical prospective cohort study (MeMo study (NTR7149)), newly diagnosed RA patients were administered oral (n=24) or subcutaneous (n=22) MTX, mostly according to the COBRA-light schedule (start 10 mg MTX, increased to 25 mg MTX in 8 weeks). At 1, 2, and 3 months after start of therapy, blood was collected and individual MTX-PGs (MTX-PG1 – MTX-PG6) were analyzed in erythrocytes at a minimal detection limit of 1 nmol/L, using a validated UHPLC-MS/MS method with labeled internal standards.1 Dosing, concomitant treatments and DAS28-ESR assessments were in conformity with clinical practice. Adverse events were recorded.

Results:

46 consecutive patients were included in this study; 76% female, mean age: 57.8 years, BMI: 25.8, 20% smokers, mean baseline DAS28-ESR: 3.5. Notwithstanding marked interpatient variability, patients starting subcutaneous MTX had accumulated significantly higher (approximately 2-fold) long chain MTX-PGs (MTX-PG4-6) when compared to patients in the oral MTX group at 1 and 2 months (Figure 1A, Table 1). Similarly, MTX-PG1-6 and MTX-PG3 accumulation were higher in subcutaneous MTX-users at month 1 (p=0.022 and p=0.011) compared to the oral group (median 68.6 nmol/L (IQR:40.5) vs 51.9 (55.6) and 17.4 (11.1) vs 11.2 (15.6), respectively (Figure 1B, Table 1).

Table 1.

Linear regression of MTX-PG levels and administration route, corrected for age, baseline DAS28, smoking, BMI, eGFR and MTX dose.

monthß (P-value)1ß (P-value)2ß (P-value)3MTX-PG1-61.65 (0.022)1.51 (0.073)1.30 (0.233)MTX-PG1,21.13 (0.599)1.19 (0.470)1.12 (0.623)MTX-PG31.75 (0.011)1.51 (0.071)1.19 (0.439)MTX-PG4-61.97 (0.036)2.04 (0.033)1.55 (0.136)

Mean MTX dose at baseline was 10.5mg (SD 1.5) for both groups, 15.4 (4.4) and 16.8 (1.8) at 1 month and 22.8 (3.9) and 22.4 (5.2) at 2 months for oral and subcutaneous use respectively.

DAS28 decreased with 1.6 in the oral group and 1.1 in the subcutaneous group (p=0.382). With and without corrections for age, baseline DAS28, eGFR, MTX dose (1 month before sampling), smoking and BMI, no significant relation between MTX-PG concentrations and DAS28 was observed during the first 3 months of treatment.

43 patients reported any side effect, mostly headache and dizziness, which was similar in both groups and uncorrelated with MTX-PG levels.

No association was found between MTX-PG1 levels and number of days between timing of blood withdrawal and last administration.

Figure 1.

Erythrocyte long chain MTX-PG(A) and total MTX-PG(B) accumulation in RA patients of the first 3 months of oral(C) or subcutaneous(D) MTX administration. At 3 months, 18 patients using oral and 18 patients using subcutaneous MTX were still continuing MTX treatment. Medians and IQR are depicted.

Conclusion:

This study shows the feasibility of measuring erythrocyte MTX-PGs early on in the treatment of RA patients with MTX and demonstrated significantly higher accumulation of MTX-PGs following subcutaneous versus oral MTX administration. Early phase erythrocyte MTX-PG analyses may hold potential for positioning in optimizing individual patient MTX dose scheduling.

References:

[1]de Rotte MC, et al. Methotrexate polyglutamates in erythrocytes are associated with lower disease activity in patients with rheumatoid arthritis. Ann Rheum Dis 2015(74):408-14.

Acknowledgements:

We would like to thank all participating patients and Pfizer (grant 53233663 / WI230458).

Disclosure of Interests:

Renske Hebing Grant/research support from: Pfizer, Ittai Muller: None declared, Marry Lin: None declared, Sohaila Mahmoud: None declared, Sandra Heil: None declared, WIllem Lems: None declared, Michael Nurmohamed: None declared, Robert De Jonge: None declared, Gerrit Jansen: None declared

OP0021 IDENTIFICATION OF DIFFERENTIALLY EXPRESSED GENES IN EARLY RHEUMATOID ARTHRITIS PATIENTS RESPONDING TO TOCILIZUMAB

Background:

Tocilizumab (TCZ) is a monoclonal antibody that binds to the interleukin 6 receptor (IL-6R), inhibiting IL-6R signal transduction to downstream inflammatory mediators. TCZ has shown to be effective as monotherapy in early rheumatoid arthritis (RA) patients (1). However, approximately one third of patients inadequately respond to therapy and the biological mechanisms underlying lack of efficacy for TCZ remain elusive (1). Here we report gene expression differences, in both whole blood and peripheral blood mononuclear cells (PBMC) RNA samples between early RA patients, categorized by clinical TCZ response (reaching DAS28 < 3.2 at 6 months). These findings could lead to identification of predictive biomarkers for TCZ response and improve RA treatment strategies.

Objectives:

To identify potential baseline gene expression markers for TCZ response in early RA patients using an RNA-sequencing approach.

Methods:

Two cohorts of RA patients were included and blood was collected at baseline, before initiating TCZ treatment (8 mg/kg every 4 weeks, intravenously). DAS28-ESR scores were calculated at baseline and clinical response to TCZ was defined as DAS28 < 3.2 at 6 months of treatment. In the first cohort (n=21 patients, previously treated with DMARDs), RNA-sequencing (RNA-seq) was performed on baseline whole blood PAXgene RNA (Illumina TruSeq mRNA Stranded) and differential gene expression (DGE) profiles were measured between responders (n=14) and non-responders (n=7). For external replication, in a second cohort (n=95 therapy-naïve patients receiving TCZ monotherapy), RNA-seq was conducted on baseline PBMC RNA (SMARTer Stranded Total RNA-Seq Kit, Takara Bio) from the 2-year, multicenter, double-blind, placebo-controlled, randomized U-Act-Early trial (ClinicalTrials.gov identifier: NCT01034137) and DGE was analyzed between 84 responders and 11 non-responders.

Results:

Whole blood DGE analysis showed two significantly higher expressed genes in TCZ non-responders (False Discovery Rate, FDR < 0.05): urotensin 2 (UTS2) and caveolin-1 (CAV1). Subsequent analysis of U-Act-Early PBMC DGE showed nine differentially expressed genes (FDR < 0.05) of which expression in clinical TCZ non-responders was significantly higher for eight genes (MTCOP12, ZNF774, UTS2, SLC4A1, FECH, IFIT1B, AHSP, and SPTB) and significantly lower for one gene (TND2P28M). Both analyses were corrected for baseline DAS28-ESR, age and gender. Expression of UTS2, with a proposed function in regulatory T-cells (2), was significantly higher in TCZ non-responders in both cohorts. Furthermore, gene ontology enrichment analysis revealed no distinct gene ontology or IL-6 related pathway(s) that were significantly different between TCZ-responders and non-responders.

Conclusion:

Several genes are differentially expressed at baseline between responders and non-responders to TCZ therapy at 6 months. Most notably, UTS2 expression is significantly higher in TCZ non-responders in both whole blood as well as PBMC cohorts. UTS2 could be a promising target for further analyses as a potential predictive biomarker for TCZ response in RA patients in combination with clinical parameters (3).

References:

[1]Bijlsma JWJ, Welsing PMJ, Woodworth TG, et al. Early rheumatoid arthritis treated with tocilizumab, methotrexate, or their combination (U-Act-Early): a multicentre, randomised, double-blind, double-dummy, strategy trial. Lancet. 2016;388(10042):343-55.

[2]Bhairavabhotla R, Kim YC, Glass DD, et al. Transcriptome profiling of human FoxP3+ regulatory T cells. Human Immunology. 2016;77(2):201-13.

[3]Gosselt HR, Verhoeven MMA, Bulatovic-Calasan M, et al. Complex machine-learning algorithms and multivariable logistic regression on par in the prediction of insufficient clinical response to methotrexate in rheumatoid arthritis. Journal of Personalized Medicine. 2021;11(1).

Disclosure of Interests:

None declared

A self-sustainable wearable multi-modular E-textile bioenergy microgrid system

Despite the fast development of various energy harvesting and storage devices, their judicious integration into efficient, autonomous, and sustainable wearable systems has not been widely explored. Here, we introduce the concept and design principles of e-textile microgrids by demonstrating a multi-module bioenergy microgrid system. Unlike earlier hybrid wearable systems, the presented e-textile microgrid relies solely on human activity to work synergistically, harvesting biochemical and biomechanical energy using sweat-based biofuel cells and triboelectric generators, and regulating the harvested energy via supercapacitors for high-power output. Through energy budgeting, the e-textile system can efficiently power liquid crystal displays continuously or a sweat sensor-electrochromic display system in pulsed sessions, with half the booting time and triple the runtime in a 10-min exercise session. Implementing "compatible form factors, commensurate performance, and complementary functionality" design principles, the flexible, textile-based bioenergy microgrid offers attractive prospects for the design and operation of efficient, sustainable, and autonomous wearable systems.

Dose-response relationship between serum fibroblast growth factor 21 and liver fat content in non-alcoholic fatty liver disease

BACKGROUND & AIM

Although serum fibroblast growth factor 21 (FGF21) levels are associated with liver fat content in non-alcoholic liver fat disease (NAFLD), the precise nature of the association remains undetermined. Therefore, this study aimed to explore the potential dose-response relationship between FGF21 and liver fat content in NAFLD.

METHODS

For this exploratory study from a randomized trial, 220 NAFLD patients with central obesity were recruited via community-based screening and randomly assigned to either control, moderate or vigorous-moderate exercise groups for 12 months. After this exercise intervention, patients were followed-up for a further 12 months. Serum FGF21 levels were measured by ELISA. Intrahepatic triglyceride (IHTG) content was determined by proton magnetic resonance spectroscopy.

RESULTS

Of the 220 patients, 149 (67.7%) were female; mean age was 53.9 ± 7.1 years and mean BMI was 28.0 ± 2.9 kg/m² for all patients. Baseline IHGT increased gradually (P = 0.029 for trend) according to baseline serum FGF21 quartiles 1, 2, 3 and 4 (212.3, 358.9, 538.7 and 793.5 pg/mL, respectively). On grouping the distribution of serum FGF21 level changes into quartiles at month 12, the relative IHTG loss increased as serum FGF21 levels were reduced (P = 0.004 for trend). A similar trend was observed at month 24 (P = 0.006 for trend). Multivariate linear regression analysis revealed that changes in serum FGF21 levels were independently associated with changes in IHTG at both month 12 [β (SE), 0.136 (0.118); P = 0.048] and month 24 [β (SE), 0.152 (0.139); P = 0.041]. Using restricted cubic spline regression, changes in serum FGF21 were strongly and positively associated with their corresponding relative IHTG loss at both month 12 and follow-up (P_overall = 0.017, P_non-linear = 0.044 and P_overall = 0.020, P_non-linear = 0.361, respectively, for dose-response).

CONCLUSION

Serum FGF21 is strongly associated with liver fat content in a dose-response manner in centrally obese NAFLD patients. These findings support the use of serum FGF21 as a biomarker of liver fat content in NAFLD.