Angiogenic imbalance in maternal and cord blood is associated with neonatal birth weight and head circumference in pregnancies with major fetal congenital heart defect

OBJECTIVES

To ascertain whether abnormalities in neonatal head circumference and/or body weight are associated with levels of angiogenic/antiangiogenic factors in the maternal and cord blood of pregnancies with a congenital heart defect (CHD) and to assess whether the specific type of CHD influences this association.

METHODS

This was a multicenter case-control study of women carrying a fetus with major CHD. Recruitment was carried out between June 2010 and July 2018 at four tertiary care hospitals in Spain. Maternal venous blood was drawn at study inclusion and at delivery. Cord blood samples were obtained at birth when possible. Placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1) and soluble endoglin (sEng) were measured in maternal and cord blood. Biomarker concentrations in the maternal blood were expressed as multiples of the median (MoM).

RESULTS

PlGF, sFlt-1 and sEng levels were measured in the maternal blood in 237 cases with CHD and 260 healthy controls, and in the cord blood in 150 cases and 56 controls. Compared with controls, median PlGF MoM in maternal blood was significantly lower in the CHD group (0.959 vs 1.022; P < 0.0001), while median sFlt-1/PlGF ratio MoM was significantly higher (1.032 vs 0.974; P = 0.0085) and no difference was observed in sEng MoM (0.981 vs 1.011; P = 0.4673). Levels of sFlt-1 and sEng were significantly higher in cord blood obtained from fetuses with CHD compared to controls (mean ± standard error of the mean, 447 ± 51 vs 264 ± 20 pg/mL; P = 0.0470 and 8.30 ± 0.92 vs 5.69 ± 0.34 ng/mL; P = 0.0430, respectively). Concentrations of sFlt-1 and the sFlt-1/PlGF ratio in the maternal blood at study inclusion were associated negatively with birth weight and head circumference in the CHD group. The type of CHD anomaly (valvular, conotruncal or left ventricular outflow tract obstruction) did not appear to alter these findings.

CONCLUSIONS

Pregnancies with fetal CHD have an antiangiogenic profile in maternal and cord blood. This imbalance is adversely associated with neonatal head circumference and birth weight. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

In Vivo Cerebral Imaging of Mutant Huntingtin Aggregates Using 11C-CHDI-180R PET in a Nonhuman Primate Model of Huntington Disease

Huntington disease (HD) is a neurodegenerative disorder caused by an expanded polyglutamine (CAG) trinucleotide expansion in the huntingtin (HTT) gene that encodes the mutant huntingtin protein (mHTT). Visualization and quantification of cerebral mHTT will provide a proxy for target engagement and a means to evaluate therapeutic interventions aimed at lowering mHTT in the brain. Here, we validated the novel radioligand 11C-labeled 6-(5-((5-methoxypyridin-2-yl)methoxy)benzo[d]oxazol-2-yl)-2-methylpyridazin-3(2H)-one (11C-CHDI-180R) using PET imaging to quantify cerebral mHTT aggregates in a macaque model of HD. Methods: Rhesus macaques received MRI-guided intrastriatal delivery of a mixture of AAV2 and AAV2.retro viral vectors expressing an HTT fragment bearing 85 CAG repeats (85Q, n = 5), a control HTT fragment bearing 10 CAG repeats (10Q, n = 4), or vector diluent only (phosphate-buffered saline, n = 5). Thirty months after surgery, 90-min dynamic PET/CT imaging was used to investigate 11C-CHDI-180R brain kinetics, along with serial blood sampling to measure input function and stability of the radioligand. The total volume of distribution was calculated using a 2-tissue-compartment model as well as Logan graphical analysis for regional quantification. Immunostaining for mHTT was performed to corroborate the in vivo findings. Results: 11C-CHDI-180R displayed good metabolic stability (51.4% ± 4.0% parent in plasma at 60 min after injection). Regional time-activity curves displayed rapid uptake and reversible binding, which were described by a 2-tissue-compartment model. Logan graphical analysis was associated with the 2-tissue-compartment model (r 2 = 0.96, P < 0.0001) and used to generate parametric volume of distribution maps. Compared with controls, animals administered the 85Q fragment exhibited significantly increased 11C-CHDI-180R binding in several cortical and subcortical brain regions (group effect, P < 0.0001). No difference in 11C-CHDI-180R binding was observed between buffer and 10Q animals. The presence of mHTT aggregates in the 85Q animals was confirmed histologically. Conclusion: We validated 11C-CHDI-180R as a radioligand to visualize and quantify mHTT aggregated species in a HD macaque model. These findings corroborate our previous work in rodent HD models and show that 11C-CHDI-180R is a promising tool to assess the mHTT aggregate load and the efficacy of therapeutic strategies.

IKBKB reduces huntingtin aggregation by phosphorylating serine 13 via a non-canonical IKK pathway

N-terminal phosphorylation at residues T3 and S13 is believed to have important beneficial implications for the biological and pathological properties of mutant huntingtin, where inhibitor of nuclear factor kappa B kinase subunit beta (IKBKB) was identified as a candidate regulator of huntingtin N-terminal phosphorylation. The paucity of mechanistic information on IKK pathways, together with the lack of sensitive methods to quantify endogenous huntingtin phosphorylation, prevented detailed study of the role of IKBKB in Huntington's disease. Using novel ultrasensitive assays, we demonstrate that IKBKB can regulate endogenous S13 huntingtin phosphorylation in a manner, dependent on its kinase activity and known regulators. We found that the ability of IKBKB to phosphorylate endogenous huntingtin S13 is mediated through a non-canonical interferon regulatory factor3-mediated IKK pathway, distinct from the established involvement of IKBKB in mutant huntingtin's pathological mechanisms mediated via the canonical pathway. Furthermore, increased huntingtin S13 phosphorylation by IKBKB resulted in decreased aggregation of mutant huntingtin in cells, again dependent on its kinase activity. These findings point to a non-canonical IKK pathway linking S13 huntingtin phosphorylation to the pathological properties of mutant huntingtin aggregation, thought to be significant to Huntington's disease.

Identification and Optimization of RNA-Splicing Modulators as Huntingtin Protein-Lowering Agents for the Treatment of Huntington's Disease

Huntington's disease (HD) is caused by an expanded CAG trinucleotide repeat in exon 1 of the huntingtin (HTT) gene. We report the design of a series of HTT pre-mRNA splicing modulators that lower huntingtin (HTT) protein, including the toxic mutant huntingtin (mHTT), by promoting insertion of a pseudoexon containing a premature termination codon at the exon 49-50 junction. The resulting transcript undergoes nonsense-mediated decay, leading to a reduction of HTT mRNA transcripts and protein levels. The starting benzamide core was modified to pyrazine amide and further optimized to give a potent, CNS-penetrant, and orally bioavailable HTT-splicing modulator 27. This compound reduced canonical splicing of the HTT RNA exon 49-50 and demonstrated significant HTT-lowering in both human HD stem cells and mouse BACHD models. Compound 27 is a structurally diverse HTT-splicing modulator that may help understand the mechanism of adverse effects such as peripheral neuropathy associated with branaplam.

Validation of LC-MS/MS methods for quantitative analysis of kynurenine pathway metabolites in human plasma and cerebrospinal fluid

Background: Dysregulation of the kynurenine metabolic pathway has been reported in several neurological conditions. Methods & results: Sensitive and selective LC-MS/MS methods have been validated for six kynurenine pathway metabolites in human cerebrospinal fluid and plasma. For each matrix, we validated three methods - one for the simultaneous determination of kynurenine, kynurenic acid, anthranilic acid and 3-hydroxy-kynurenine (four-analyte assay), one for quinolinic acid and one for tryptophan - using stable-isotopically labeled internal standards. The dynamic range and quantitation limits were based on endogenous concentrations for each analyte. Conclusion: The use of validated methods for kynurenine pathway metabolites in human cerebrospinal fluid and plasma will provide definitive information in neurological diseases.

Design and Evaluation of [18F]CHDI-650 as a Positron Emission Tomography Ligand to Image Mutant Huntingtin Aggregates

Therapeutic interventions are being developed for Huntington's disease (HD), a hallmark of which is mutant huntingtin protein (mHTT) aggregates. Following the advancement to human testing of two [¹¹C]-PET ligands for aggregated mHTT, attributes for further optimization were identified. We replaced the pyridazinone ring of CHDI-180 with a pyrimidine ring and minimized off-target binding using brain homogenate derived from Alzheimer's disease patients. The major in vivo metabolic pathway via aldehyde oxidase was blocked with a 2-methyl group on the pyrimidine ring. A strategically placed ring-nitrogen on the benzoxazole core ensured high free fraction in the brain without introducing efflux. Replacing a methoxy pendant with a fluoro-ethoxy group and introducing deuterium atoms suppressed oxidative defluorination and accumulation of [¹⁸F]-signal in bones. The resulting PET ligand, CHDI-650, shows a rapid brain uptake and washout profile in non-human primates and is now being advanced to human testing.

ODP109 PARATHYROID HORMONE AND 25 OH VITAMINA D IN PREGNANCY: DATA FROM AN ARGENTINEAN COHORT SUPPORTING SUPPLEMENTATION

 

Vitamin D (Vit D) deficiency has become a global health care issue, as it affects a great number of women during pregnancy and lactation. Vit D levels are critical during pregnancy, being the mother the only source of them for the developing fetus; an enzymatic system for conversion of 25OH VitD into 1-25(OH) 2 VitD is present in the placenta, thus reinforcing the importance of VitD during gestation. VitD deficiency has been associated with obstetric complications and adverse outcomes in offspring, affecting skeletal, immunological and respiratory systems. It is known that prenatal supplements available do not contain enough VitD to fulfil requirements. It is generally accepted that elevated PTH is an indicator of VitD deficiency, and Hysaj O et al (2021) showed that 25OH VitD is a statistically significant determinant of PTH levels in early and late pregnancy.

Aim

To evaluateVitD status and its relationship to parathyroid hormone (PTH) in a cohort of pregnant women representative of multiple Argentinian regions.

Subjects and Methods

Data from samples of 423 pregnant women in 1st and 2nd trimester were collected between 2016 and 2021. VitD was measured in different platforms: DiaSorin Liaison CLIA (n=184), Roche COBAS ECLIA (n=166), Abbott ARCHITECT CMIA (n=33), Biomérieux VIDAS ELFA (n=18) and Siemens CENTAUR CLIA (n=16). PTH (ng/L) was measured in 162 samples by SIEMENS IMMULITE CLIA and Roche COBAS ECLIA. As VitD is light-exposure dependent, we considered warm and high light-exposure season period from December to March and cold and low light season from April to September. VITD (ng/L) levels were classified as Deficient (<20), Insufficient (between 21 and 29) and Sufficient (>30) (Endocrine Society, 2014).

Results

From 423 data collected, 102 were excluded because of lacking information on VitD supplementation. From the remaining non supplemented 321 samples, 48% resulted insufficient, 30% deficient and 22% sufficient for VitD (groups comparison: p< 0. 05, Kruskal Wallis-Dunn test). The seasonal period and pregnancy trimester distributions didn't show significant differences. Similar results of VitD insufficiency were found in the major used platforms, regardless the seasonal period considered. PTH results expressed as median and interquartile range were (ng/L): 32. 0 (13.7-169. 0) in Deficient pregnancies (N=92), 23.7(13.3-88. 0) in Insufficient (n=50) and 18.7 (9.8-55.7) in Sufficient (n=20).

Conclusions

This study shows VitD inadequate levels in 78% in non-supplemented pregnancies, regardless season or measurement platform. Relative elevated levels of PTH were associated to pregnancies with VitD deficiency, evidenciating a regulatory role according to published data. To improve VitD status during pregnancy it would be advisable to pose new strategies for prenatal supplements developed by a multidisciplinary professional team.

Presentation: No date and time listed

Validation, kinetic modeling, and test-retest reproducibility of [18F]SynVesT-1 for PET imaging of synaptic vesicle glycoprotein 2A in mice

Alterations in synaptic vesicle glycoprotein 2 A (SV2A) have been associated with several neuropsychiatric and neurodegenerative disorders. Therefore, SV2A positron emission tomography (PET) imaging may provide a unique tool to investigate synaptic density dynamics during disease progression and after therapeutic intervention. This study aims to extensively characterize the novel radioligand [¹⁸F]SynVesT-1 for preclinical applications. In C57Bl/6J mice (n = 39), we assessed the plasma profile of [¹⁸F]SynVesT-1, validated the use of a noninvasive image-derived input function (IDIF) compared to an arterial input function (AIF), performed a blocking study with levetiracetam (50 and 200 mg/kg, i.p.) to verify the specificity towards SV2A, examined kinetic models for volume of distribution (V_T) quantification, and explored test-retest reproducibility of [¹⁸F]SynVesT-1 in the central nervous system (CNS). Plasma availability of [¹⁸F]SynVesT-1 decreased rapidly (13.4 ± 1.5% at 30 min post-injection). V_T based on AIF and IDIF showed excellent agreement (r² = 0.95, p < 0.0001) and could be reliably estimated with a 60-min acquisition. The blocking study resulted in a complete blockade with no suitable reference region. Test-retest analysis indicated good reproducibility (mean absolute variability <10%). In conclusion, [¹⁸F]SynVesT-1 is selective for SV2A with optimal kinetics representing a candidate tool to quantify CNS synaptic density non-invasively.

Developing HDAC4-Selective Protein Degraders To Investigate the Role of HDAC4 in Huntington's Disease Pathology

Huntington's disease (HD) is a lethal autosomal dominant neurodegenerative disorder resulting from a CAG repeat expansion in the huntingtin (HTT) gene. The product of translation of this gene is a highly aggregation-prone protein containing a polyglutamine tract >35 repeats (mHTT) that has been shown to colocalize with histone deacetylase 4 (HDAC4) in cytoplasmic inclusions in HD mouse models. Genetic reduction of HDAC4 in an HD mouse model resulted in delayed aggregation of mHTT, along with amelioration of neurological phenotypes and extended lifespan. To further investigate the role of HDAC4 in cellular models of HD, we have developed bifunctional degraders of the protein and report the first potent and selective degraders of HDAC4 that show an effect in multiple cell lines, including HD mouse model-derived cortical neurons. These degraders act via the ubiquitin-proteasomal pathway and selectively degrade HDAC4 over other class IIa HDAC isoforms (HDAC5, HDAC7, and HDAC9).

Identification of a Potent, Selective, and Brain-Penetrant Rho Kinase Inhibitor and its Activity in a Mouse Model of Huntington's Disease

The Rho kinase (ROCK) pathway is implicated in the pathogenesis of several conditions, including neurological diseases. In Huntington's disease (HD), ROCK is implicated in mutant huntingtin (HTT) aggregation and neurotoxicity, and members of the ROCK pathway are increased in HD mouse models and patients. To validate this mode of action as a potential treatment for HD, we sought a potent, selective, central nervous system (CNS)-penetrant ROCK inhibitor. Identifying a compound that could be dosed orally in mice with selectivity against other AGC kinases, including protein kinase G (PKG), whose inhibition could potentially activate the ROCK pathway, was paramount for the program. We describe the optimization of published ligands to identify a novel series of ROCK inhibitors based on a piperazine core. Morphing of the early series developed in-house by scaffold hopping enabled the identification of a compound exhibiting high potency and desired selectivity and demonstrating a robust pharmacodynamic (PD) effect by the inhibition of ROCK-mediated substrate (MYPT1) phosphorylation after oral dosing.

AB1339 MUSCLE ULTRASOUND FOR THE DIAGNOSIS OF SARCOPENIA IN RHEUMATOID ARTHRITIS (RA)

Background

Sarcopenia is a muscular disease characterized by a loss of muscle mass and function. The condition is associated with chronic diseases and ageing and predicts disability, hospitalization and death (1). Due to chronicity and disability produced by RA, it is convenient to see the relationship with sarcopenia.

Objectives

To assess the diagnostic utility of ultrasound (US) for sarcopenia.

Methods

Cases: Outpatients, 65 years old or more, with RA (ACR/EULAR 2010 criteria) from the rheumatology clinics of 4 Spanish University Hospitals were randomly selected consecutively from rheumatology consultation since May 2021 to September 2021. Controls: Control subjects without rheumatoid disease were selected from family members or friends of the cases, paired by age, gender and social status from May to September 2021.

Variable and measures:

The main evaluated outcome was sarcopenia as defined in 2019 by the European Working Group on Sarcopenia in Older People (EWGSOP). Crossectional Ultrasounds (US) of the third proximal forearm were evaluated for the perpendicular distance (milimetres) between superficial surface of subcutaneous celular tissue and the deep surface close to the ulnae with two different measures (66% and 75%).

Crossectional US images were also obtained of lower limbs, at an equidistant point between anterosuperior iliac spine and the upper border of the patella for measuring the distance between superficial surface of subcutaneous celular tissue and the deep interface of the femur with vastus medialis muscle with two different measures (50% and 75%).

Handheld dynamometer was used to measure the strength in upper limbs.

Body composition was evaluated using dual-energy X-ray densitometry.

Statistics: A descriptive analysis, chi square y T-student tests were done to compare the main characteristics and results between patients and controls. Correlations between forearm US and strength and between thigh US and total DEXA were calculated by Pearson’s test.

Results

76 patients and 76 controls were included in the study, 120 were women (78,9%), with media ± SD of age 74,7 ±6,98 of media and 32 (21,1%) were men, with age 70,1 ±3,78 of media. In comparation with controls, RA patients presented more frequency of sarcopenia (30 [19,53%] vs 6 [3,94%]; p=0,005) according to EWGSOP criteria.

From the point of view of ultrasound, RA patients presented less muscle mass in cubital forearm and thigh. Control group presented larger size of muscle (Table 1).

Table 1.

Results measirements case-control in milimeters

Control (m±ds)RA (m±ds)p-valorRight forearm 66% ulnar42,92±838,72±9,330,003Left forearm 66% ulnar41,17±8,9737,93±9,270,03Left forearm 75% cubital38,74±7,735,18±8,50,008Right Thigh 50% FR+VI30,9±7,4628,09±6,310,011Right Thigh 50%VI14,5±4,2613,08±4,270,042Right Thigh 50% FR15,26±3,613,5±3,280,002Right Thigh 50% area FR588±181,29481,49±140,560,001Lefth Thigh 50% FR+VI27,67±8,922,37±8,26<0,001

Ultrasound measurements in forearm which showed a positive correlation with strength were: right forearm: 66% ulnar (r=0,364, p=0,001), 75% ulnar (r=0,365, p=0,001); left forearm: 66% ulnar (r=0,348, p=0,002), 75% ulnar (r=0,337, p=0,003). In the other hand, ultrasound measurements in thigh which showed a positive correlation with DXA were: right thigh 50% femoral rectus (FR)-vastus intermedius (VI) (r=0,255, p=0,003), 50% VI (r=0,256,p=0,003), 50% FR (r=0,265, p=0,002), 50% area FR (r=0,280, p=0,003), 75% FR-VI (r=0,357,p<0,001), 75% VI (r=0,382,p<0,001), 75% FR (r=0,240, R2=0,006), 75% area FR (r=0,218,p=0,023); Left thigh: 50% FR-VI (r=0,251, p=0,004), 50% VI (r=0,293,p=0,001), 50% FR (r=0,214, p=0,015), 75% FR-VI (r=0,347,p<0,001), 75% VI (r=0,342, p<0,001), 75% FR (r=0,295, p=0,001).

Conclusion

Muscle Ultrasound is a useful diagnostic tool to detect sarcopenia. It can be cost-efficient and faster when compared with DEXA and the results correlate consistently with the strength in forearm. Patients with rheumatoid arthritis are in high risk of suffering sarcopenia and US could be used to control the evolution of this condition.

Disclosure of Interests

None declared

POS1556-HPR RECOMMENDATIONS FOR NURSES ON THE MANAGEMENT OF PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOUS: A DELPHI CONSENSUS

Background

Nurses play a key role in the management of Systemic Lupus Erythematosus (SLE) due to their close contact with the patient. Well-structured resources and specialized training are necessary to ensure comprehensive and quality care. However, no complete clinical practice guidelines for nurses have been developed for the management of SLE in Spain or Europe [1].

Objectives

In this context, the OpenReuma scientific society decided to promote the RECOMIENDAles project, the aim of which is to create consensus-based recommendations for the management of SLE patients by nurses in Spain.

Methods

Following a bibliographic review, the Delphi method [2] was followed to reach the consensus and a structured survey was sent to nurses with expertise in SLE. Two successive rounds were conducted. Consensus was established when at least 70% of the panelists agreed or disagreed on a topic.

The final questionnaire contained 90 items divided into 3 sections (Figure 1).

Results

In Spain, few nurses could be considered experts in SLE, hence the number of panelists was small: 25 nurses from different specialties (Rheumatology: 80%, Autoimmune Disease Units: 4%, Internal Medicine: 4%, and Day Hospital Services: 12%) with sufficient experience to ensure validated recommendations that could translate into practice. All the participants worked in public hospitals and had more than 2 years of experience treating SLE patients.

A high consensus was reached on the role and responsibilities that nurses should have in relation to SLE patient management. The main results are summarized in Table 1.

Table 1.

Summary of the main recommendations reached in the RECOMIENDAles Project.

RECOMMENDATIONS% of agreement (7 – 9 score)General recommendations•Multidisciplinary teams with at least one nurse trained in SLE100%•Participate throughout the SLE patient care process and have their own agenda of visits and content92%•Psychological and social worker support96%•Access to continuous training (SLE management, individual and group counselling and communication techniques)100%•Access to research projects96%Specific recommendationsDiagnosis:•Inform the patient about the diagnosis (manage expectations and resolve doubts and fears)100%•Provide contact channels with the service and reliable sources of information100%•Collaborate in the physical examination92%•Collaborate performing diagnostic tests76%Education:•Have a structured plan for patient education, engaging family and friends100%•Inform about the pathology (disease course, symptoms indicating aggravation, comorbidities)96%•Inform about healthy lifestyle habits (diet, hydration, exercise, rest patterns, photoprotection measures), avoiding toxic habits such as alcohol or smoking100%Treatment:•Play an active role in treatment training, including self-administration and adherence monitoring100%•Take part in the decision to introduce injectable therapy at home76%•Prepare a youth-adult therapeutic transition plan100%Follow-up:•Supervise patient condition to prevent comorbidities (diabetes, obesity, osteoporosis, cardiovascular problems)96%•Promote family planning measures100%•Monitor patient needs during the youth-adult transition96%

Conclusion

Despite the high consensus achieved, to bring these recommendations to fruition it is necessary to: 1) Reinforce the role and presence of the specialized nurse in multidisciplinary teams treating SLE patients; 2) Establish a specific training plan for nurses: accredited, subsidized and supported by the Scientific Societies; and 3) Create detailed clinical practice guidelines for the SLE nurse specialist.

References

[1]Urizar E, Antepara C, Urtaran-Laresgoiti M, Nuño-Solinís R. Servicios de Reumatología en España: Estado de situación. 2019.

[2]Dalkey NC. The Delphi Method: An Experimental Study of Group Opinion. Santa Monica Rand Corp [Internet]. RAND Corporation; 1969 [cited 2021 Nov 19]; Available from: https://www.rand.org/pubs/research_memoranda/RM5888.html

Acknowledgements

We would like to thank all the expert nurses who participated in the RECOMIENDAles Delphi Project, without whom this project would not have been possible: Ana Isabel Rodríguez Vargas (Canarias University Hospital, Santa Cruz de Tenerife); Carmen Domínguez Quesada (Virgen Macarena University Hospital, Seville); Coral Mouriño Rodríguez (do Meixoeiro Hospital, Pontevedra); Cristina Campins Reus (Manacor Hospital, Balearic Islands); Esther Vílchez Ocaña (Marítimo Torremolinos Hospital, Málaga); Idoya Piudo de Blas (Navarra Hospital Complex, Navarra); Isabel Pozo Jiménez (University Hospital of Jerez de la Frontera, Cádiz); Jenny de la Torre Aboki (General and University Hospital, Alicante); José María Martín Martín (Nuestra Señora de Candelaria University Hospital, Santa Cruz de Tenerife); Juan Crisostomo Vacas Pérez (Reina Sofía University Hospital, Murcia); Laura Cano García (Malaga Regional University Hospital, Malaga); Manuel Moreno Galeano (Virgen Macarena University Hospital, Seville); Maria Rodero López (San Carlos Clinical Hospital, Madrid); María Amparo Molina Tercero (University Hospital of Gran Canaria Dr. Negrin, Las Palmas de Gran Canaria); María del Carmen Herrero Manso (12 de Octubre University Hospital, Madrid), Maria Dolores Aragón Álvarez (San Cecilio University Hospital, Granada); María Isabel Castro López (University Hospital Complexo of Santiago, A Coruña); María Luisa Uriondo Martínez (A Coruña University Hospital, A Coruña); Marta Rodríguez Álvarez (Burgos University Hospital, Burgos); Noor Al-Mashhandani (Civil Hospital of Malaga, Malaga); Nuria Sapena Fortea (Barcelona Clinic Hospital, Barcelona); Patricia García Casado (Ramón y Cajal University Hospital, Madrid); Rosa Serrano Loro (Germans Tries i Pujol Hospital, Barcelona); Silvia García Díaz (Sant Joan Despí Moisès Broggi Hospital, Barcelona) and Susana Fernández Sánchez (Santa Creu and Sant Pau Hospital, Barcelona).

We would like to thank GSK for its financial support to this project. We would also like to thank Adelphi Targis S.L. for the logistical support provided to develop the project.

Disclosure of Interests

Laura Cano Garcia Consultant of: GSK, fees for her advice as a member of the Scientific Committee of the RECOMIENDAles Project., Carmen Dominguez Consultant of: GSK, fees for her advice as a member of the Scientific Committee of the RECOMIENDAles Project., Ana Isabel Rodriguez Vargas Consultant of: GSK, fees for her advice as a member of the Scientific Committee of the RECOMIENDAles Project., ELISA TRUJILLO MARTIN Consultant of: GSK, fees for her advice as a member of the Scientific Committee of the RECOMIENDAles Project., José Maria Martín Martín Consultant of: GSK, fees for his advice as a member of the Scientific Committee of the RECOMIENDAles Project.

AB0255 SARCOPENIA IN PATIENTS WITH RHEUMATOID ARTHRITIS OVER 65 YEARS OF AGE: PREVALENCE AND PREDISPOSING FACTORS

Background

Sarcopenia is a muscle disease which is characterized by loss of muscle mass and function. This condition is associated with chronic disease and ageing which predicts inability, hospitalization and death.

Objectives

Describe sarcopenia prevalence and risk factors in patients with reumathoid arthritis (RA) over 65 years of age.

Methods

Design:

A case-control study.

Subjects

Cases: Recruitment was performed by random sampling between patients over 65 years of age with RA (ACR/EULAR 2010 criteria) attended at 4 Spanish University Hospitals.

Controls: Recruitment of subjects without rheumatoid disease was performed asking for case patients who attended to medical center with a similar-age (age of range +/- 5 years) and same-gender person from same social or family environment.

Variables: The main variable was sarcopenia which was defined according to European Working Group on Sarcopenia in Older People (EWGSOP) 2019. Sarcopenia risk factors assessed were: economic status, malnutrition, measured with Mini Nutritional Assessment (MNA), dual-energy x-ray absorptiometry (DEXA) in spine and hip to osteoporose screening, toxic habits, comorbidities and Charlson index, physical activity measured with Global physical activity questionnaire (GPAQ) and Short Physical Performance Battery (SPPB).

Other variables were: haemoglobin, calcium, D and B12 vitamins, total proteins, albumin, C reactive protein, body mass index (BMI), polimedication, quality of life measured with EQ-5D and RA related factors, activity disease measured with DAS28, SDAI and CDAI; physical function measured with HAQ (Health assessment questionnaire) and global functional status according ACR criteria.

Statistical analysis:

Descriptive and multivariative analysis was performed to identify factors associated to sarcopenia in RA.

Results

76 patients and 76 controls were included in the study, 120 were women (78,9%), with media ± SD of age 74,7 ±6,98 of media and 32 (21,1%) were men, with age 70,1 ±3,78 of media. In comparation with controls, RA patients presented more frequency of sarcopenia (30 [19,53%] vs 6 [3,94%]; p=0,005). RA patients who presented sarcopenia, were upper average age (p=0,001), worse results in Short Physical Performance Battery (SPPB) (p=0,037), higher DAS28 (3,55 ± 1,09 vs 2,78 ± 1,05; p=0,017), higher score HAQ (1,18 ± 0,79 vs 1,69 ± 0,68; p=0,024), worse score in EQ5D (0,27 ± 0,28 vs. 0,54 ± 0,25; p=0,001) and Visual analogic scale VAS EQ5D (45,7 ± 17,4 vs. 56,9 ± 17,6; p=0,035).

By the way, RA patients presented lower levels of total proteins (p=0,018), worse results in MNA (p=0,001) and they performed less physical activity by GPAQ (p=0,011). Multivariative models (Table 1) identified as independent predictors of sarcopenia in RA: age (p=0,014), proteins levels (p=0,044) and disease activity measured by DAS28 (p=0,030). This model could explain 37% of sarcopenia in RA (R2=0,37).

Table 1.

Multivariativeanalysis (VD: Sarcopenia)

OR(IC)pAge, years1,213 (1,041-1,414)0,014Proteins (g/dL)0,185 (0,036-0,958)0,044DAS282,146(1,076-4,881)0,030

R2=0,37

Conclusion

Sarcopenia is more prevalence in over 65 years-old RA people. Older age and higher activity disease measured by DAS28 more risk of sarcopenia. Proteins levels have a protected association with sarcopenia.

Disclosure of Interests

None declared

AB1545-HPR MALNUTRITION IN PATIENTS WITH RHEUMATOID ARTHRITIS OVER 65 YEARS OF AGE

Background

Malnutrition is one of the most important geriatric syndrome and fragility factor in older people. In adittion to being a disease sign, its presence is related with increasing of morbility, longer hospitalizations, institucionalization and mortality due to concomitant diseases.

Objectives

Describe prevalence of malnutrition risk and associated factor in patients with rheumatoid arthritis (RA) over 65 years of age.

Methods

Design:

A case-controls study.

Participants:

Cases: Recruitment was performed by random sampling between patients over 65 years of age with RA (ACR/EULAR 2010 criteria) attended at 4 Spanish University Hospitals. Controls: Recruitment of subjects without rheumatoid disease was performed asking for case patients who attended to medical center with a similar-age (age of range +/- 5 years) and same-gender person from same social or family environment.

Variables y measures:

The main variable was malnutrition risk, measured by screening of Mini Nutritional Assessment.

Other variables were: presence of sarcopenia, defined according to European Working Group on Sarcopenia in Older People (EWGSOP) 2019, economic status, dual-energy x-ray absorptiometry (DEXA) in spine and hip to osteoporose screening, toxic habits, comorbidities and Charlson index, physical activity measured with Global physical activity questionnaire (GPAQ) and Short Physical Performance Battery (SPPB), haemoglobin, calcium, D and B12 vitamins, total proteins, albumin, C reactive protein, body mass index (BMI), polimedication, quality of life measured with EQ-5D and RA related factors, activity disease measured with DAS28, SDAI and CDAI; physical function measured with HAQ (Health assessment questionnaire) and global functional status according ACR criteria.

Statistical analysis: Descriptive and multivariative analysis was performed to identify factors associated to sarcopenia in RA.

Results

152 subjects were included in the study, 76 RA and 76 controls.More patients than controls with malnutrition risk were found, although there were no significative difference (24 [31,6%] vs 17 [22,4%]; p=0,136). More women with RA were included (78,9%), with media ± SD of age 74,7 ± 3,78., sarcopenia was presented in 9/24 (37,5%) and Charlson index was 3 points in 11/24 patients (45,8%) and 4 points in 8/24 patients (33,3%). According to the treatment, almost a 40%, no DMARDs were taken and neither 25% biological DMARD. 58,3 % of patients received corticosteroids and mayority of them (95,8%) were polimedicated. RA patients who presented desnutrition risk, in comparison with the rest of patients, had a media of upper age (p=0,007), more frequency of sarcopenia (p=0,006), right tricipital skinfold thickness (p=0,043). Also, higher values were found in activity index like physical function and quality of life: DAS28 (p=0,003), HAQ (p=0,044), Vitamin D (p=0,035), IPAQ (p=0,003), SPPB (p=0,018), EQ5D (p=0,01), VAS EQ5D (p=0,044), SDAI (p= 0,006), CDAI (p=0,008). In multivariative análisis, factors associated by independent way to malnutrition risk were age (OR [CI 95%], 1,148 [1,020-1,291]; p=0,022) and inflammatory disease by DAS28 (OR [CI 95%], 2,043 [1,198-3,483]; p=0,009) (R2=0,252).

Conclusion

Even though frequency of malnutrition was similar in cases and controls, in RA was associated with inflammatory activity and older age. It´s important monitoring malnutrition risk in this kind of patients to perform correct interventions to prevent and improve nutrition.

Disclosure of Interests

None declared

OP0213-HPR RECOMMENDATIONS FOR NURSES IN THE MANAGEMENT OF RA PATIENTS ON TREATMENT WITH JAKINIBS

Background

The number of new treatments available in rheumatology continues to increase. Kinase inhibitors, or jakinibs, pose an added challenge due to their variety and because they are oral. The most important role of the rheumatology nurse is patient education, especially on how to take the medication. The better the nurse understands the drugs, the better their practical recommendations and decisions will be and the better they will be able to respond to the patient. Guidelines or recommendations for inflammatory diseases do not usually include key practical details for nurses. It is our understanding that these points that will subsequently determine adherence and safety should be specially addressed in a specific document for nurses.

Objectives

To establish practical, evidence-based nursing recommendations for the management of people with RA undergoing treatment with jakinibs.

Methods

To reach an evidence-based consensus we used systematic review and Delphi survey. A multidisciplinary panel of experts was formed with 6 rheumatology nurses, 2 rheumatologists, 1 psychologist, 1 dietician-nutritionist and 1 patient on treatment with jakinibs. This panel met on 2 occasions and was kept informed at all times of the progress of the project through the Miro platform. At the preparatory meeting the scope and users, structure and PICOt questions were established (these included efficacy and adverse effects, infections, cardiovascular risk, surgery, vaccination, pregnancy and breastfeeding, interactions and switches between jakinibs).

The steering group made recommendations based on the issues raised at the first meeting. Only those that achieved 65% in favour were included as items in a Delphi survey. The Delphi survey was sent to all members of the society nurses and rheumatologists (n=60). Voting ranged from 0 to 10 (strongly disagree to strongly agree). Items with more than 75% agreement in the first round did not proceed to a second round.

Results

The Table 1 shows the recommendations with their level of evidence and level of agreement after the Delphi (n=40; 67%). One item with only 50% agreement was rejected and did not proceed to a second round.

Table 1.RecommendationLevel of evidenceDegree of agreementBefore starting treatment with a jakinib, it should be confirmed that the patient has no contraindications.5100%The patient’s efficacy and outcome expectations for the drug should be explored and those that need to be adjusted.585%It should be indicated that a double dose should not be taken if one is missed.4100%As with other DMARDs, the patient should be instructed that close management will follow.599%The use of contraception and discontinuation of the drug is recommended in case of gestational desire or unplanned pregnancy.396%It is recommended to explain the warning signs of infection: fever, blisters, burning pain in the ribs, itching when urinating, productive cough, diarrhoea, pus-filled wounds, phlegmon.1a100%It is recommended to instruct the patient on preventive measures for infectious diseases (dental and hand hygiene, HPV, social distance, etc.).1a89%Vaccination against common germs in immunocompromised persons and shingles with the current vaccine is recommended.1a93%CV risk factors should be monitored, and the patient trained for signs of thrombosis, HF or ischaemic heart disease.1a89%Close monitoring of elderly patients (CV risk, infections) is recommended.2100%Emphasis on adherence is recommended for jakinibs to be effective.3100%Before surgery, discontinuation of jakinib should be scheduled depending on the type of surgery and comorbidities.389%

Conclusion

These recommendations will allow a practical approach to the management of jakinibs by nurses and enjoy an adequate consensus among potential users.

Disclosure of Interests

José Maria Martín Martín Speakers bureau: Lilly, Consultant of: Lilly, Grant/research support from: Galapagos, Silvia García-Díaz Grant/research support from: Galapagos, Amparo Molina Grant/research support from: Galapagos, Carmen Dominguez Grant/research support from: Galapagos, Loreto Carmona: None declared, Laura Cano Garcia Grant/research support from: Galapagos

Development of a ligand for in vivo imaging of mutant huntingtin in Huntington's disease

Huntington's disease (HD) is a dominantly inherited neurodegenerative disorder caused by a CAG trinucleotide expansion in the huntingtin (HTT) gene that encodes the pathologic mutant HTT (mHTT) protein with an expanded polyglutamine (polyQ) tract. Whereas several therapeutic programs targeting mHTT expression have advanced to clinical evaluation, methods to visualize mHTT protein species in the living brain are lacking. Here, we demonstrate the development and characterization of a positron emission tomography (PET) imaging radioligand with high affinity and selectivity for mHTT aggregates. This small molecule radiolabeled with ¹¹C ([¹¹C]CHDI-180R) allowed noninvasive monitoring of mHTT pathology in the brain and could track region- and time-dependent suppression of mHTT in response to therapeutic interventions targeting mHTT expression in a rodent model. We further showed that in these animals, therapeutic agents that lowered mHTT in the striatum had a functional restorative effect that could be measured by preservation of striatal imaging markers, enabling a translational path to assess the functional effect of mHTT lowering.

Synaptic vesicle glycoprotein 2A is affected in the CNS of Huntington's Disease mice and post-mortem human HD brain

Synaptic dysfunction is a primary mechanism underlying Huntington's Disease (HD) progression. This study investigated changes in synaptic vesicle glycoprotein 2A (SV2A) density by means of ¹¹C-UCB-J microPET imaging in the central nervous system (CNS) of HD mice. METHODS: Dynamic ¹¹C-UCB-J microPET imaging was performed at clinically relevant disease stages (at 3, 7, 10, and 16 months, M) in the heterozygous knock-in Q175DN mouse model of HD and WT littermates (n = 16-18/genotype and time point). Cerebral ¹¹C-UCB-J analyses were performed to assess genotypic differences during pre-symptomatic (3M) and symptomatic (7-16M) disease stages. ¹¹C-UCB-J binding in the spinal cord was quantified at 16M. 3H-UCB-J autoradiography and SV2A immunofluorescence were performed post-mortem in mouse and human brain tissue. RESULTS: ¹¹C-UCB-J binding was declined in symptomatic heterozygous mice compared to WT littermates in parallel with disease progression (7M: p<0.01, 16M: p<0.0001). Specific ¹¹C-UCB-J binding was detectable in the spinal cord, with symptomatic heterozygous mice displaying a significant reduction (p<0.0001). 3H-UCB-J autoradiography and SV2A immunofluorescence corroborated the in vivo measurements demonstrating lowered SV2A in heterozygous mice (p<0.05). Finally, preliminary analysis of SV2A in post-mortem human brain suggested lower SV2A in HD gene carrier compared to nondemented control. CONCLUSION: ¹¹C-UCB-J PET detects SV2A deficits during symptomatic disease in heterozygous mice in both brain and spinal cord, offering a novel marker of synaptic integrity widely distributed in CNS. Upon clinical application, ¹¹C-UCB-J PET imaging yields promise for SV2A measurement in patients with HD during disease progression and following disease-modifying therapeutic strategies.

Pharmacokinetics and metabolic disposition of a potent and selective kynurenine monooxygenase inhibitor, CHDI-340246, in laboratory animals

The disposition of a novel kynurenine monooxygenase inhibitor, CHDI-340246, was investigated in vitro and in animals.In vitro, there was minimal metabolic turnover of CHDI-340246 in all species. The protein binding was higher in human plasma (99.7%) relative to other species.In all species, blood clearance was low (<20% of liver blood flow) and volume of distribution was small (<0.5 L/kg). The terminal half-life was longer in monkeys (9 hr) than in mice, rats, or dogs (1-2 hr). CHDI-340246 was orally bioavailable (>60%) in all species.In rats, [¹⁴C]CHDI-340246 showed wide distribution of radioactivity in all tissues except brain and testes. In rats, the parent drug was the major circulating moiety with minor amounts of a sulphate conjugate of an O-dealkylated metabolite. The elimination occurred via the urinary route and to a lesser extent by biliary route, but mostly as metabolites. In cynomolgus monkeys, the parent drug predominated in plasma with only trace amounts of metabolites detected.Acyl glucuronide conjugate of CHDI-340246 was not detected in plasma of rats or monkeys.Overall, the ADME profile of CHDI-340246 was favourable in rats and monkeys for potential evaluation of KMO inhibition in humans.

Pharmacological characterization of mutant huntingtin aggregate-directed PET imaging tracer candidates

Huntington’s disease (HD) is caused by a CAG trinucleotide repeat expansion in the first exon of the huntingtin (HTT) gene coding for the huntingtin (HTT) protein. The misfolding and consequential aggregation of CAG-expanded mutant HTT (mHTT) underpin HD pathology. Our interest in the life cycle of HTT led us to consider the development of high-affinity small-molecule binders of HTT oligomerized/amyloid-containing species that could serve as either cellular and in vivo imaging tools or potential therapeutic agents. We recently reported the development of PET tracers CHDI-180 and CHDI-626 as suitable for imaging mHTT aggregates, and here we present an in-depth pharmacological investigation of their binding characteristics. We have implemented an array of in vitro and ex vivo radiometric binding assays using recombinant HTT, brain homogenate-derived HTT aggregates, and brain sections from mouse HD models and humans post-mortem to investigate binding affinities and selectivity against other pathological proteins from indications such as Alzheimer’s disease and spinocerebellar ataxia 1. Radioligand binding assays and autoradiography studies using brain homogenates and tissue sections from HD mouse models showed that CHDI-180 and CHDI-626 specifically bind mHTT aggregates that accumulate with age and disease progression. Finally, we characterized CHDI-180 and CHDI-626 regarding their off-target selectivity and binding affinity to beta amyloid plaques in brain sections and homogenates from Alzheimer’s disease patients.

[11C]CHDI-626, a PET Tracer Candidate for Imaging Mutant Huntingtin Aggregates with Reduced Binding to AD Pathological Proteins

The expanded polyglutamine-containing mutant huntingtin (mHTT) protein is implicated in neuronal degeneration of medium spiny neurons in Huntington's disease (HD) for which multiple therapeutic approaches are currently being evaluated to eliminate or reduce mHTT. Development of effective and orthogonal biomarkers will ensure accurate assessment of the safety and efficacy of pharmacologic interventions. We have identified and optimized a class of ligands that bind to oligomerized/aggregated mHTT, which is a hallmark in the HD postmortem brain. These ligands are potentially useful imaging biomarkers for HD therapeutic development in both preclinical and clinical settings. We describe here the optimization of the benzo[4,5]imidazo[1,2-a]pyrimidine series that show selective binding to mHTT aggregates over Aβ- and/or tau-aggregates associated with Alzheimer's disease pathology. Compound [11C]-2 was selected as a clinical candidate based on its high free fraction in the brain, specific binding in the HD mouse model, and rapid brain uptake/washout in nonhuman primate positron emission tomography imaging studies.

In vitro and In vivo Assessment of Suitable Reference Region and Kinetic Modelling for the mGluR1 Radioligand [11C]ITDM in Mice

PURPOSE

This study aimed at investigating binding specificity, suitability of reference region-based kinetic modelling, and pharmacokinetics of the metabotropic glutamate receptor 1 (mGluR1) radioligand [¹¹C]ITDM in mice.

PROCEDURES

We performed in vivo blocking as well as displacement of [¹¹C]ITDM during positron emission tomography (PET) imaging using the specific mGluR1 antagonist YM-202074. Additionally, we assessed in vitro blocking of [³H]ITDM at two different doses of YM-202074. As an alternative to reference region models, we validated the use of a noninvasive image-derived input function (IDIF) compared to an arterial input function measured with an invasive arteriovenous (AV) shunt using a population-based curve for radiometabolite correction and characterized the pharmacokinetic modelling of [¹¹C]ITDM in the mouse brain. Finally, we also assessed semi-quantitative approaches.

RESULTS

In vivo blocking with YM-202074 resulted in a decreased [¹¹C]ITDM binding, ranging from - 35.8 ± 8.0 % in pons to - 65.8 ± 3.0 % in thalamus. Displacement was also markedly observed in all tested regions. In addition, in vitro [³H]ITDM binding could be blocked in a dose-dependent manner. The volume of distribution (V_T) based on the noninvasive IDIF (V_{T (IDIF)}) showed excellent agreement with the V_T values based on the metabolite-corrected plasma input function regardless of the metabolite correction (r² > 0.943, p < 0.0001). Two-tissue compartmental model (2TCM) was found to be the preferred model and showed optimal agreement with Logan plot (r² > 0.960, p < 0.0001). A minimum scan duration of 80 min was required for proper parameter estimation. SUV was not reliable (r² = 0.379, p = 0.0011), unlike the SUV ratio to the SUV of the input function, which showed to be a valid approach.

CONCLUSIONS

No suitable reference region could be identified for [¹¹C]ITDM as strongly supported by in vivo and in vitro evidence of specific binding in all brain regions. However, by applying appropriate kinetic models, [¹¹C]ITDM PET imaging represents a promising tool to visualize mGluR1 in the mouse brain.

POS0475 INTEGRATIVE CLINICAL, MOLECULAR AND COMPUTATIONAL ANALYSES ALLOW THE IDENTIFICATION OF DISTINCTIVE PHENOTYPES OF RHEUMATOID ARTHRITIS PATIENTS RELATED TO THE CLINICAL INVOLVEMENT AND THE RESPONSE TO TNF INHIBITORS

Background:

TNF inhibitors (TNFi) represent an extraordinary advance in the management of Rheumatoid Arthritis (RA). Despite their benefits, there is a percentage of patients (20–40%) that do not achieve clinical improvement. Therefore, it is necessary to search for new and easily accessible biomarkers predictive of therapeutic response that might guide precision medicine.

Objectives:

1. To explore changes in the molecular profile of RA patients following TNFi therapy in serum samples. 2. To search for new and reliable biomarkers predictive of TNFi response, based on clinical and molecular profiles of RA patients, by using machine learning algorithms.

Methods:

In a prospective multicenter study, 79 RA patients undergoing TNFi and 29 healthy donors (HD) were enrolled. Twenty-two RA patients were further included as a validation cohort. Serum samples were obtained before and after 6 months of treatment, and therapeutic efficacy was evaluated. Patients’ response was determined following EULAR response criteria. Serum inflammatory profile was analyzed by a multiplex immunoassay, along with oxidative and NETotic profiles, evaluated by commercial kits. A circulating miRNA array was also performed by next-generation sequencing. Clustering analysis was carried out to identify groups of patients with distinctive molecular signatures. Then, clinical and molecular changes induced by TNFi were delineated after 6 months of therapy. Finally, integrative clinical and molecular signatures as predictors of response were assessed at baseline by supervised machine learning methods, using regularized logistic regressions.

Results:

Inflammatory, oxidative stress and NETosis-derived biomolecules were found altered in RA patients versus HD, closely interconnected and associated with several deregulated miRNAs. This altered molecular profile at baseline allowed the unsupervised division of three clusters of RA patients with distinctive clinical phenotypes, further linked to TNFi effectiveness. Cluster 1 included RA patients with low levels of pro-inflammatory cytokines, associated with a medium-low disease activity score and good clinical response. Clusters 2-3 comprised patients with high levels of pro-inflammatory cytokines, associated with a high disease activity and a non-response rate of 30%.

After 6 months of therapy the molecular profile found altered in RA patients was reversed in responder patients, who achieved a molecular phenotype similar to HDs. However, non-responder patients’ molecular profile remained significantly deregulated, including alterations in inflammatory mediators (IL-6, L-8, TNFα, VEGF, IL-1RA, IL-5, IL-15, GMCSF, GCSF, FGFb), oxidative stress markers (LPO) and NETosis-derived products (Elastase), along with specific miRNAs (miR-199a-5p). These molecular changes further correlated with changes in disease activity score. Machine-learning algorithms identified clinical (Creatinine, IgM, Vitamin D, Swollen Joints, C4, Disease Duration and Tryglicerides) and molecular (Nucleosomes, IL-10, miR-106a-5p, IL-13, IL-12p70, IL-15 and LPO) signatures as potential predictors of response to TNFi treatment with high accuracy. Furthermore, the integration of both features in a combined model increased the predictive value of these signatures (AUC: 0.91). These results were further confirmed in an independent validation cohort.

Conclusion:

1. RA patients display distinctive altered molecular profiles directly linked to their clinical status and associated with TNFi effectiveness. 2. Clinical response was associated with a specific modulation of the inflammatory profile, the reestablishment of the altered oxidative status, the reduction of NETosis and the reversion of related altered miRNAs. 3. The integrative analysis of the clinical and molecular profiles using machine learning allows the identification of novel signatures as potential predictors of therapeutic response to TNFi therapy.

Disclosure of Interests:

None declared

Structure-Based Exploration of Selectivity for ATM Inhibitors in Huntington's Disease

Our group has recently shown that brain-penetrant ataxia telangiectasia-mutated (ATM) kinase inhibitors may have potential as novel therapeutics for the treatment of Huntington's disease (HD). However, the previously described pyranone-thioxanthenes (e.g., 4) failed to afford selectivity over a vacuolar protein sorting 34 (Vps34) kinase, an important kinase involved with autophagy. Given that impaired autophagy has been proposed as a pathogenic mechanism of neurodegenerative diseases such as HD, achieving selectivity over Vps34 became an important objective for our program. Here, we report the successful selectivity optimization of ATM over Vps34 by using X-ray crystal structures of a Vps34-ATM protein chimera where the Vps34 ATP-binding site was mutated to approximate that of an ATM kinase. The morpholino-pyridone and morpholino-pyrimidinone series that resulted as a consequence of this selectivity optimization process have high ATM potency and good oral bioavailability and have lower molecular weight, reduced lipophilicity, higher aqueous solubility, and greater synthetic tractability compared to the pyranone-thioxanthenes.

Evaluation of 5-(Trifluoromethyl)-1,2,4-oxadiazole-Based Class IIa HDAC Inhibitors for Huntington's Disease

Using an iterative structure-activity relationship driven approach, we identified a CNS-penetrant 5-(trifluoromethyl)-1,2,4-oxadiazole (TFMO, 12) with a pharmacokinetic profile suitable for probing class IIa histone deacetylase (HDAC) inhibition in vivo. Given the lack of understanding of endogenous class IIa HDAC substrates, we developed a surrogate readout to measure compound effects in vivo, by exploiting the >100-fold selectivity compound 12 exhibits over class I/IIb HDACs. We achieved adequate brain exposure with compound 12 in mice to estimate a class I/IIb deacetylation EC₅₀, using class I substrate H4K12 acetylation and global acetylation levels as a pharmacodynamic readout. We observed excellent correlation between the compound 12 in vivo pharmacodynamic response and in vitro class I/IIb cellular activity. Applying the same relationship to class IIa HDAC inhibition, we estimated the compound 12 dose required to inhibit class IIa HDAC activity, for use in preclinical models of Huntington's disease.

Kinetic Modelling and Test-Retest Reproducibility for the Dopamine D1R Radioligand [11C]SCH23390 in Healthy and Diseased Mice

Purpose

Our aim in this study was to compare different non-invasive pharmacokinetic models and assess test–retest reproducibility of the radioligand [¹¹C]SCH23390 for the quantification of dopamine D₁-like receptor (D₁R) in both wild-type (WT) mice and heterozygous (HET) Q175DN mice as Huntington’s disease (HD) model.

Procedures

Adult WT (n = 9) and HET (n = 14) mice underwent a 90-min [¹¹C]SCH23390 positron emission tomography (PET) scan followed by computed tomography (CT) to evaluate the pharmacokinetic modelling in healthy and diseased conditions. Additionally, 5 WT mice and 7 HET animals received a second [¹¹C]SCH23390 PET scan for test–retest reproducibility. Parallel assessment of the simplified reference tissue model (SRTM), the multilinear reference tissue model (MRTM) and the Logan reference tissue model (Logan Ref) using the striatum as a receptor-rich region and the cerebellum as a receptor-free (reference) region was performed to define the most suitable method for regional- and voxel-based quantification of the binding potential (BP_ND). Finally, standardised uptake value ratio (SUVR-1) was assessed as a potential simplified measurement.

Results

For all models, we measured a significant decline in dopamine D₁R density (e.g. SRTM = − 38.5 ± 5.0 %, p < 0.0001) in HET mice compared to WT littermates. Shortening the 90-min scan duration resulted in large underestimation of striatal BP_ND in both WT mice (SRTM 60 min: − 17.7 ± 2.8 %, p = 0.0078) and diseased HET (SRTM 60 min: − 13.1 ± 4.1 %, p = 0.0001). Striatal BP_ND measurements were very reproducible with an average test–retest variability below 5 % when using both MRTM and SRTM. Parametric BP_ND maps generated with SRTM were highly reliable, showing nearly perfect agreement to the regional analysis (r² = 0.99, p < 0.0001). Finally, SRTM provided the most accurate estimate for relative tracer delivery R₁ with both regional- and voxel-based analyses. SUVR-1 at different time intervals were not sufficiently reliable when compared to BP_ND (r² < 0.66).

Conclusions

Ninety-minute acquisition and the use of SRTM for pharmacokinetic modelling is recommended. [¹¹C]SCH23390 PET imaging demonstrates optimal characteristics for the study of dopamine D₁R density in models of psychiatric and neurological disorders as exemplified in the Q175DN mouse model of HD.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11307-020-01561-1.

Reduction of the Carbapenemase Inactivation Method (CIM) assay time by real-time PCR

Carbapenemase Inactivation Method (CIM) is a test to detect presence of the carbapenemase in Gram-negative bacteria. Determination of the carbapenemase production by inactivation of meropenem requires that a zone of control E. coli inhibition be measured approximately 6-24 h after plating. We have modified the CIM test by developing a rapid method which instead measures the growth of E. coli indicator strain ATCC 25922 using real-time PCR, referred to as a nucleic acid testing CIM (natCIM). Our natCIM, therefore reduces the detecting time from 6 to 24 h to approximately 4 h.

Optimization of linear and cyclic peptide inhibitors of KEAP1-NRF2 protein-protein interaction

Inhibition of KEAP1-NRF2 protein-protein interaction is considered a promising strategy to selectively and effectively activate NRF2, a transcription factor which is involved in several pathologies such as Huntington's disease (HD). A library of linear peptides based on the NRF2-binding motifs was generated on the nonapeptide lead Ac-LDEETGEFL-NH₂ spanning residues 76-84 of the Neh2 domain of NRF2 with the aim to replace E78, E79 and E82 with non-acidic amino acids. A deeper understanding of the features and accessibility of the T80 subpocket was also targeted by structure-based design. Approaches to improve cell permeability were investigated using both different classes of cyclic peptides and conjugation to cell-penetrating peptides. This insight will guide future design of macrocycles, peptido-mimetics and, most importantly, small neutral brain-penetrating molecules to evaluate whether NRF2 activators have utility in HD.

Imaging Mutant Huntingtin Aggregates: Development of a Potential PET Ligand

Mutant huntingtin (mHTT) protein carrying the elongated N-terminal polyglutamine (polyQ) tract misfolds and forms protein aggregates characteristic of Huntington's disease (HD) pathology. A high-affinity ligand specific for mHTT aggregates could serve as a positron emission tomography (PET) imaging biomarker for HD therapeutic development and disease progression. To identify such compounds with binding affinity for polyQ aggregates, we embarked on systematic structural activity studies; lead optimization of aggregate-binding affinity, unbound fractions in brain, permeability, and low efflux culminated in the discovery of compound 1, which exhibited target engagement in autoradiography (ARG) studies in brain slices from HD mouse models and postmortem human HD samples. PET imaging studies with ¹¹C-labeled 1 in both HD mice and WT nonhuman primates (NHPs) demonstrated that the right-hand-side labeled ligand [¹¹C]-1R (CHDI-180R) is a suitable PET tracer for imaging of mHTT aggregates. [¹¹C]-1R is now being advanced to human trials as a first-in-class HD PET radiotracer.

AB1355-HPR THE IMPACT OF A STRUCTURED TRAINING PROGRAMME FOR THE DETECTION OF SYNOVITIS WITH MUSCULOSKELETAL ULTRASOUND (MSUS) IN RHEUMATOLOGY NURSING

Background:

Objectives:

To analyse the effect of a teaching intervention for the technical performance of a reduced index of ultrasound synovitis by nurses without previous experience in musculoskeletal ultrasound (MSUS).

Methods:

Design: Quasi-experimental study of the before-after type. Protocol: The nurses received a theoretical-practical, face-to-face and intensive training of 8 hours, by an expert rheumatologist in musculoskeletal ultrasound (MSUS), to perform the Perricone index, which assesses the presence of grey-scale synovitis (GS) and quantifies the presence of a power-doppler (PD) signal semiquantitatively (0-3), in 6 joints (Wrists, 2nd Metacarpophalangeal (MCP) joints and knees). The theoretical knowledge acquired was assessed by an exam test type at the end of the training, and the technical skills were assessed by an ultrasound examination in patients with rheumatoid arthritis, immediately after the teaching session and at 18 months later. Variables: Illumination of the consultation, protection of privacy and unequivocal identification of the patient, technique (explorer ergonomics, bilateral comparison, use of both hands, measurement, marking and saving data), GS (probe position, centred image, cortical-cartilage-tendon display, depth, focus, frequency, gain), PD (probe pressure, PRF, position-width-depth of the box, focus, frequency, gain), synovial recesses (dorsal and palmar examination of the wrist, 2nd Metacarpophalangeal (MCP) joints and supra and parapatellar medial and lateral examination of the knees) and semi-quantitative gradation of synovitis in GS and PD. Statistical analysis: descriptive analysis, and in relation to the statistical significance tests for paired variables (pre and post teaching intervention) the McNemar test was used for dichotomous qualitative variables and McNemar-Bowker test for those of more than two categories.

Results:

5 nurses, 80% women, aged between 36 and 54 years participated. They adequately answered 100% of the 4-student test questions, and the remaining one matched 80% of them. The average time of baseline exploration was 45,2 ±3,8 minutes and the final time was 32,6 ± 3,5, improving the 5 students in an average of 12,6± 4,4 minutes. The technical aspects not performed correctly in the baseline ultrasound examination were the bilateral comparative, centred image, grey scale gain, measuring, correct anatomical image of the synovial recess of the wrist and position-width-depth of the Doppler box. An improvement was observed at 18 months in the unequivocal identification of the patient, adequate illumination of the consultation, bilateral comparison, correct anatomical acquisition of synovial recesses and the quantification of GS synovitis, but no statistically significant differences were observed, before and after the teaching intervention, in possible relation with the difficulty to use the ultrasound in their respective Rheumatology Units in clinical practice, but mainly because the aspects correctly performed in the baseline exploration were numerous.

Conclusion:

A formal training of rheumatology nurses in musculoskeletal ultrasound (MSUS) could be very useful, and cost-efficient, in the health care of patients with rheumatoid arthritis.

Disclosure of Interests:

None declared

SAT0043 SERUM BIOMOLECULES AS POTENTIAL BIOMARKERS OF CLINICAL EFFICACY AND PREDICTORS OF RESPONSE TO BIOLOGIC DISEASE MODIFYING ANTI-RHEUMATIC DRUGS IN RHEUMATOID ARTHRITIS PATIENTS

Objectives:

To evaluate the changes promoted in levels of circulating inflammatory mediators in RA patients in response to TNF-α inhibitors (TNFi) and anti-CD20 therapies, in order to identify biomarkers of clinical efficacy and potential predictors of therapeutic response to these drugs.

Methods:

In a prospective RA cohort multicenter study, we collected serum from RA patients with moderate or high disease activity prior and after 6 months of treatment with TNFi or rituximab (RTX), and analyzed levels of 27 proteins that constitute a multi-biomarker test of the inflammatory profile of these samples, using a multiplex immunoassay. Patients’ response was determined according to the EULAR response criteria (good/moderate/no). We compared basal levels of inflammatory molecules between the differential response patient groups and analyzed their discriminative ability. Logistic prediction models were created to assess the added value of potential inflammatory predictors.

Results:

Among 111 total RA patients, 50 of 85 (59%) patients in the TNFi group and 18 of 26 patients in the RTX group (69%) responded to the biologic treatment. High DAS28 or SDAI scores, or titers of auto-antibodies (RF or ACPA) at baseline were not predictive of response to any treatment. Instead, smoking habit and hyperlipidemia at baseline were predictors of a worse response to any of these bDMARDs.

Of the molecules analyzed by the multiplex assay, 14 inflammatory mediators showed a significant downregulation on patients’ responders to TNFi therapy. Moreover, the decline on 7 biomolecules was related to reduced DAS28. After RTX treatment, 15 inflammatory mediators were reduced in patients with good clinical response; downregulation in 4 of those biomolecules correlated with reduced DAS28.

In the search for predictors of response to each bDMARD, by using the MetaboAnalyst software, we could classify patients with distinctive therapeutic response based on the baseline levels of the inflammatory molecules analyzed. Receiver operating characteristic (ROC) analyses for those multiple biomarkers allowed us to further identify specific signatures of inflammatory biomolecules that may serve as predictors of response to each bDMARD therapy with high sensitivity and specificity. Thus, a signature of five molecules was identified as potential predictor of TNFi response [Vascular endothelial growth factor (VEGF), Eotaxin, RANTES, IL7 and IL-17]. Indeed, a signature including three highly expressed cytokines/chemokines in RA serum were identified as predictors of RTX response [interferon-inducible protein 10 (IP10), Eotaxin and monocyte chemotactic protein 1 (MCP-1)].

Conclusion:

The extensive analysis of serum inflammatory profile allowed to identify specific and distinctive signatures of biomolecules that, in coordination with known clinical and serological profiles, might predict the response of RA patients to TNFi or RTX treatments.

Acknowledgments :

Funded by Junta de Andalucía (PI-0285-2017), ISCIII, (PI18/00837 and RIER RD16/0012/0015) co-funded with FEDER

Disclosure of Interests:

María Luque-Tévar: None declared, Carlos Perez-Sanchez: None declared, Font Ugalde Pilar: None declared, Montserrat Romero-Gómez: None declared, Alejandra M. Patiño-Trives: None declared, Desiree Ruiz: None declared, Iván Arias de la Rosa: None declared, Maria del Carmen Abalos-Aguilera: None declared, Rafaela Ortega Castro: None declared, Alejandro Escudero Contreras: None declared, Carlos Rodríguez-Escalera Speakers bureau: Lilly, GSK, Novartis and Sanofi, José Javier Pérez Venegas: None declared, María Dolores Ruiz Montesinos: None declared, Carmen Dominguez: None declared, Carmen Romero Barco: None declared, Antonio Fernandez-Nebro: None declared, Natalia Mena-Vázquez: None declared, Jose Luis Marenco Speakers bureau: ABbvie, Pfzer, lilly, Julia Uceda: None declared, Mª Dolores Toledo-Coello: None declared, Nuria Barbarroja Puerto Grant/research support from: ROCHE and Pfizer., Speakers bureau: ROCHE and Celgene., Maria A Aguirre: None declared, Chary Lopez-Pedrera Grant/research support from: ROCHE and Pfizer., Eduardo Collantes-Estévez Grant/research support from: ROCHE and Pfizer., Speakers bureau: ROCHE, Lilly, Bristol and Celgene.

Validation and noninvasive kinetic modeling of [11C]UCB-J PET imaging in mice

Synaptic pathology is associated with several brain disorders, thus positron emission tomography (PET) imaging of synaptic vesicle glycoprotein 2A (SV2A) using the radioligand [¹¹C]UCB-J may provide a tool to measure synaptic alterations. Given the pivotal role of mouse models in understanding neuropsychiatric and neurodegenerative disorders, this study aims to validate and characterize [¹¹C]UCB-J in mice. We performed a blocking study to verify the specificity of the radiotracer to SV2A, examined kinetic models using an image-derived input function (IDIF) for quantification of the radiotracer, and investigated the in vivo metabolism. Regional TACs during baseline showed rapid uptake of [¹¹C]UCB-J into the brain. Pretreatment with levetiracetam confirmed target engagement in a dose-dependent manner. V_{T (IDIF)} values estimated with one- and two-tissue compartmental models (1TCM and 2TCM) were highly comparable (r=0.999, p < 0.0001), with 1TCM performing better than 2TCM for K_{1 (IDIF)}. A scan duration of 60 min was sufficient for reliable V_{T (IDIF)} and K_{1 (IDIF)} estimations. In vivo metabolism of [¹¹C]UCB-J was relatively rapid, with a parent fraction of 22.5 ± 4.2% at 15 min p.i. In conclusion, our findings show that [¹¹C]UCB-J selectively binds to SV2A with optimal kinetics in the mouse representing a promising tool to noninvasively quantify synaptic density in comparative or therapeutic studies in neuropsychiatric and neurodegenerative disorder models.

Combined Peptide and Small-Molecule Approach toward Nonacidic THIQ Inhibitors of the KEAP1/NRF2 Interaction

The NRF2-ARE pathway is an intrinsic mechanism of defense against oxidative stress. Inhibition of the interaction between NRF2 and its main negative regulator KEAP1 is an attractive strategy toward neuroprotective agents. We report here the identification of nonacidic tetrahydroisoquinolines (THIQs) that inhibit the KEAP1/NRF2 protein-protein interaction. Peptide SAR at one residue is utilized as a tool to probe structural changes within a specific pocket of the KEAP1 binding site. We used structural information from peptide screening at the P2 pocket, noncovalent small-molecules inhibitors, and the outcome from an explorative SAR at position 5 of THIQs to identify a series of neutral THIQ analogs that bind to KEAP1 in the low micromolar range. These analogs establish new H-bond interactions at the P3 and P2 pockets allowing the replacement of the carboxylic acid functionality by a neutral primary carboxamide. X-ray crystallographic studies reveal the novel binding mode of these molecules to KEAP1.

Elevated Type 1 Metabotropic Glutamate Receptor Availability in a Mouse Model of Huntington's Disease: a Longitudinal PET Study

Impairment of group I metabotropic glutamate receptors (mGluRs) results in altered glutamate signalling, which is associated with several neurological disorders including Huntington’s Disease (HD), an autosomal neurodegenerative disease. In this study, we assessed in vivo pathological changes in mGluR1 availability in the Q175DN mouse model of HD using longitudinal positron emission tomography (PET) imaging with the radioligand [¹¹C]ITDM. Ninety-minute dynamic PET imaging scans were performed in 22 heterozygous (HET) Q175DN mice and 22 wild-type (WT) littermates longitudinally at 6, 12, and 16 months of age. Analyses of regional volume of distribution with an image-derived input function (V_{T (IDIF)}) and voxel-wise parametric V_{T (IDIF)} maps were performed to assess differences between genotypes. Post-mortem evaluation at 16 months was done to support in vivo findings. [¹¹C]ITDM V_{T (IDIF)} quantification revealed higher mGluR1 availability in the brain of HET mice compared to WT littermates (e.g. cerebellum: + 15.0%, + 17.9%, and + 17.6% at 6, 12, and 16 months, respectively; p < 0.001). In addition, an age-related decline in [¹¹C]ITDM binding independent of genotype was observed between 6 and 12 months. Voxel-wise analysis of parametric maps and post-mortem quantifications confirmed the elevated mGluR1 availability in HET mice compared to WT littermates. In conclusion, in vivo measurement of mGluR1 availability using longitudinal [¹¹C]ITDM PET imaging demonstrated higher [¹¹C]ITDM binding in extra-striatal brain regions during the course of disease in the Q175DN mouse model.

Premature placental aging in term small-for-gestational-age and growth-restricted fetuses

OBJECTIVE

To perform a comprehensive assessment of the placental aging process in small term fetuses classified as being small-for-gestational age (SGA) or having fetal growth restriction (FGR) through analysis of senescence and apoptosis markers.

METHODS

This was a prospective nested case-control study of singleton pregnancies delivered at term, including 21 control pregnancies with normally grown fetuses and 36 with a small fetus classified as SGA (birth weight between the 3^rd and 9^th percentiles and normal fetoplacental Doppler; n = 18) or FGR (birth weight < 3^rd percentile and/or abnormal cerebroplacental ratio and/or uterine artery Doppler; n = 18). Telomerase activity, telomere length (quantified by comparing the amount of amplification product for the telomere sequence (T) to that of a single copy of the gene 36B4 (S)) and RNA expression of senescence (Sirtuins 1, 3 and 6) and apoptosis (p53, p21, BAX and Caspases 3 and 9) markers (analyzed using the 2^-ΔΔCt method) were determined in placental samples collected at birth and compared between the three groups.

RESULTS

Compared to pregnancies with a normally grown fetus, both SGA and FGR pregnancies presented signs of accelerated placental aging, including lower telomerase activity (mean ± SD, 12.8 ± 6.6% in controls vs 7.98 ± 4.2% in SGA vs 7.79 ± 4.6% in FGR; P = 0.008), shorter telomeres (mean ± SD T/S ratio, 1.20 ± 0.6 in controls vs 1.08 ± 0.9 in SGA vs 0.66 ± 0.5 in FGR; P = 0.047) and reduced Sirtuin-1 RNA expression (mean ± SD 2^-ΔΔCt , 1.55 ± 0.8 in controls vs 0.91 ± 0.8 in SGA vs 0.63 ± 0.5 in FGR; P = 0.001) together with increased p53 RNA expression (median (interquartile range) 2^-ΔΔCt , 1.07 (0.3-3.3) in controls vs 5.39 (0.6-15) in SGA vs 3.75 (0.9-7.8) in FGR; P = 0.040). FGR cases presented signs of apoptosis, with increased Caspase-3 RNA levels (median (interquartile range) 2^-ΔΔCt , 0.94 (0.7-1.7) in controls vs 3.98 (0.9-31) in FGR; P = 0.031) and Caspase-9 RNA levels (median (interquartile range) 2^-ΔΔCt , 1.21 (0.6-4.0) in controls vs 3.87 (1.5-9.0) in FGR; P = 0.037) compared with controls. In addition, Sirtuin-1 RNA expression, telomerase activity, telomere length and Caspase-3 activity showed significant linear trends across groups as severity of the condition increased.

CONCLUSIONS

Accelerated placental aging was observed in both clinical forms of late-onset fetal smallness (SGA and FGR), supporting a common pathophysiology and challenging the concept of SGA fetuses being constitutionally small. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

MR-based spatial normalization improves [18F]MNI-659 PET regional quantification and detectability of disease effect in the Q175 mouse model of Huntington's disease

The positron emission tomography (PET) tracer [¹⁸F]MNI-659, selective for phosphodiesterase 10A (PDE10A), is a promising tool to assess an early biomarker for Huntington’s disease (HD). In this study we investigated [¹⁸F]MNI-659 uptake in the Q175 mouse model of HD. Given the focal striatal distribution of PDE10A as well as the striatal atrophy occurring in HD, the spatial normalization approach applied during the processing could sensibly affect the accuracy of the regional quantification. We compared the use of a magnetic resonance images (MRI) template based on individual MRI over a PET and CT templates for regional quantification and spatial normalization of [¹⁸F]MNI-659 PET images. We performed [¹⁸F]MNI-659 PET imaging in six months old heterozygous (HET) Q175 mice and wild-type (WT) littermates, followed by X-ray computed tomography (CT) scan. In the same week, individual T₂-weighted MRI were acquired. Spatial normalization and regional quantification of the PET/CT images was performed on MRI, [¹⁸F]MNI-659 PET, or CT template and compared to binding potential (BP_ND) using volumes manually delineated on the individual MR images. Striatal volume was significantly reduced in HET mice (-7.7%, p<0.0001) compared to WT littermates. [¹⁸F]MNI-659 BP_ND in striatum of HET animals was significantly reduced (p<0.0001) when compared to WT littermates using all three templates. However, BP_ND values were significantly higher for HET mice using the PET template compared to the MRI and CT ones (p<0.0001), with an overestimation at lower activities. On the other hand, the CT template spatial normalization introduced larger variability reducing the effect size. The PET and CT template-based approaches resulted in a lower accuracy in BP_ND quantification with consequent decrease in the detectability of disease effect. This study demonstrates that for [¹⁸F]MNI-659 brain PET imaging in mice the use of an MRI-based spatial normalization is recommended to achieve accurate quantification and fully exploit the detectability of disease effect.

Noninvasive Relative Quantification of [11C]ABP688 PET Imaging in Mice Versus an Input Function Measured Over an Arteriovenous Shunt

Impairment of the metabotropic glutamate receptor 5 (mGluR5) has been implicated with various neurologic disorders. Although mGluR5 density can be quantified with the PET radiotracer [¹¹C]ABP688, the methods for reproducible quantification of [¹¹C]ABP688 PET imaging in mice have not been thoroughly investigated yet. Thus, this study aimed to assess and validate cerebellum as reference region for simplified reference tissue model (SRTM), investigate the feasibility of a noninvasive cardiac image-derived input function (IDIF) for relative quantification, to validate the use of a PET template instead of an MRI template for spatial normalization, and to determine the reproducibility and within-subject variability of [¹¹C]ABP688 PET imaging in mice. Blocking with the mGluR5 antagonist MPEP resulted in a reduction of [¹¹C]ABP688 binding of 41% in striatum (p < 0.0001), while no significant effect could be found in cerebellum (−4.8%, p > 0.99) indicating cerebellum as suitable reference region for mice. DVR-1 calculated using a noninvasive IDIF and an arteriovenous input function correlated significantly when considering the cerebellum as the reference region (striatum: DVR-1, r = 0.978, p < 0.0001). Additionally, strong correlations between binding potential calculated from SRTM (BP_ND) with DVR-1 based on IDIF (striatum: r = 0.980, p < 0.0001) and AV shunt (striatum: r = 0.987, p < 0.0001). BP_ND displayed higher discrimination power than V_T values in determining differences between wild-types and heterozygous Q175 mice, an animal model of Huntington's disease. Furthermore, we showed high agreement between PET- and MRI-based spatial normalization approaches (striatum: r = 0.989, p < 0.0001). Finally, both spatial normalization approaches did not reveal any significant bias between test-retest scans, with a relative difference below 5%. This study indicates that noninvasive quantification of [¹¹C]ABP688 PET imaging is reproducible and cerebellum can be used as reference region in mice.

Quantifying autophagy using novel LC3B and p62 TR-FRET assays

Autophagy is a cellular mechanism that can generate energy for cells or clear misfolded or aggregated proteins, and upregulating this process has been proposed as a therapeutic approach for neurodegenerative diseases. Here we describe a novel set of LC3B-II and p62 time-resolved fluorescence resonance energy transfer (TR-FRET) assays that can detect changes in autophagy in the absence of exogenous labels. Lipidated LC3 is a marker of autophagosomes, while p62 is a substrate of autophagy. These assays can be employed in high-throughput screens to identify novel autophagy upregulators, and can measure autophagy changes in cultured cells or tissues after genetic or pharmacological interventions. We also demonstrate that different cells exhibit varying autophagic responses to pharmacological interventions. Overall, it is clear that a battery of readouts is required to make conclusions about changes in autophagy.