A multi-ancestry GWAS of Fuchs corneal dystrophy highlights the contributions of laminins, collagen, and endothelial cell regulation

Fuchs endothelial corneal dystrophy (FECD) is a leading indication for corneal transplantation, but its molecular etiology remains poorly understood. We performed genome-wide association studies (GWAS) of FECD in the Million Veteran Program followed by multi-ancestry meta-analysis with the previous largest FECD GWAS, for a total of 3970 cases and 333,794 controls. We confirm the previous four loci, and identify eight novel loci: SSBP3, THSD7A, LAMB1, PIDD1, RORA, HS3ST3B1, LAMA5, and COL18A1. We further confirm the TCF4 locus in GWAS for admixed African and Hispanic/Latino ancestries and show an enrichment of European-ancestry haplotypes at TCF4 in FECD cases. Among the novel associations are low frequency missense variants in laminin genes LAMA5 and LAMB1 which, together with previously reported LAMC1, form laminin-511 (LM511). AlphaFold 2 protein modeling, validated through homology, suggests that mutations at LAMA5 and LAMB1 may destabilize LM511 by altering inter-domain interactions or extracellular matrix binding. Finally, phenome-wide association scans and colocalization analyses suggest that the TCF4 CTG18.1 trinucleotide repeat expansion leads to dysregulation of ion transport in the corneal endothelium and has pleiotropic effects on renal function.

Editorial Commentary: Biocomposite Implant Combined With Local Human Recombinant Parathyroid Hormone Enhances the Histological Quality and Biomechanical Strength of Rotator Cuff Repairs

Rates of rotator cuff repair retear remain unacceptably high and are frequently the source of diminished shoulder function and patient dissatisfaction. Endocrinopathies have been implicated in these processes. Parathyroid hormone (PTH) activates chondrogenesis and angiogenesis at the enthesis and prevents fatty infiltration and atrophy in rotator cuff musculature. These facts have spurred interest in the therapeutic benefits of PTH as a means to enhance tendon healing and strengthen the bone in and around tendon repairs. New research demonstrates that recombinant human PTH delivered locally through a process of coupling it to a bioengineered scaffold "sheath" may be beneficial. The growth factor, encased within polycaprolactone (PCL), is slowly released as the PCL degrades to extend drug delivery time. The augmentation of rotator cuff repairs with this biocomposite material improves short-term structural tissue integrity and promotes the formation of more organized and stronger tendon-to-bone interface in a rabbit model.

Analysis of the Caribbean Neurosurgery Workforce: Scope of Practice, Challenges, and Ways Forward

BACKGROUND

The neurosurgical workforce in the Caribbean and surrounding countries is largely unknown due to the diversity in cultural, linguistic, political, financial disparities, and colonial history between the countries. About 45 neurosurgeons serve 16 million people in the Caribbean Community and Common Market, a trade alliance including most Caribbean nations. We aimed to understand the current scope of neurosurgical workforce in this region while highlighting any system challenges and potential solutions for upscaling the workforce.

METHODS

We surveyed neurosurgeons within Caribbean countries and surrounding countries online using qualitative and quantitative methods via Qualtrics.

RESULTS

Of the 38 countries within the Caribbean and surrounding countries, 26 (68%) were surveyed and of which 18 (69%) replied. In total, 172 regional neurosurgeons were identified, of which 61 (35%) replied-with a majority of general neurosurgeons (56%). Remarkably, the majority of countries failed to meet the threshold workforce density for safe health care-either expressed by full-time equivalent neurosurgeons or neurosurgical centers (see table). Most neurosurgical practices confirmed receiving or sending medical referrals. If so, most referrals took longer than 8 hours without significant difference regarding the destination. Lastly, challenges confronting neurosurgical advancement were found in the following: technology and equipment (40%), trained personnel (31%), hospital or medical center infrastructure (14%), neurosurgical education, and training (44%).

CONCLUSIONS

To our knowledge, this is the first qualitative and quantitative study exploring the current status of the neurosurgical workforce within the Caribbean and surrounding countries. Identifying resources and challenges can contribute to improving regionalized neurosurgical care.

Shared genetic basis informs the roles of polyunsaturated fatty acids in brain disorders

The neural tissue is rich in polyunsaturated fatty acids (PUFAs), components that are indispensable for the proper functioning of neurons, such as neurotransmission. PUFA nutritional deficiency and imbalance have been linked to a variety of chronic brain disorders, including major depressive disorder (MDD), anxiety, and anorexia. However, the effects of PUFAs on brain disorders remain inconclusive, and the extent of their shared genetic determinants is largely unknown. Here, we used genome-wide association summary statistics to systematically examine the shared genetic basis between six phenotypes of circulating PUFAs (N = 114,999) and 20 brain disorders (N = 9,725-762,917), infer their potential causal relationships, identify colocalized regions, and pinpoint shared genetic variants. Genetic correlation and polygenic overlap analyses revealed a widespread shared genetic basis for 77 trait pairs between six PUFA phenotypes and 16 brain disorders. Two-sample Mendelian randomization analysis indicated potential causal relationships for 16 pairs of PUFAs and brain disorders, including alcohol consumption, bipolar disorder (BIP), and MDD. Colocalization analysis identified 40 shared loci (13 unique) among six PUFAs and ten brain disorders. Twenty-two unique variants were statistically inferred as candidate shared causal variants, including rs1260326 (GCKR), rs174564 (FADS2) and rs4818766 (ADARB1). These findings reveal a widespread shared genetic basis between PUFAs and brain disorders, pinpoint specific shared variants, and provide support for the potential effects of PUFAs on certain brain disorders, especially MDD, BIP, and alcohol consumption.

Multi-ancestry GWAS of Fuchs corneal dystrophy highlights roles of laminins, collagen, and endothelial cell regulation

Fuchs endothelial corneal dystrophy (FECD) is a leading indication for corneal transplantation, but its molecular pathophysiology remains poorly understood. We performed genome-wide association studies (GWAS) of FECD in the Million Veteran Program (MVP) and meta-analyzed with the previous largest FECD GWAS, finding twelve significant loci (eight novel). We further confirmed the TCF4 locus in admixed African and Hispanic/Latino ancestries, and found an enrichment of European-ancestry haplotypes at TCF4 in FECD cases. Among the novel associations are low frequency missense variants in laminin genes LAMA5 and LAMB1 which, together with previously reported LAMC1, form laminin-511 (LM511). AlphaFold 2 protein modeling suggests that mutations at LAMA5 and LAMB1 may destabilize LM511 by altering inter-domain interactions or extracellular matrix binding. Finally, phenome-wide association scans and co-localization analyses suggest that the TCF4 CTG18.1 trinucleotide repeat expansion leads to dysregulation of ion transport in the corneal endothelium and has pleiotropic effects on renal function.

Correction: Genome-wide association study of fish oil supplementation on lipid traits in 81,246 individuals reveals new gene-diet interaction loci

[This corrects the article DOI: 10.1371/journal.pgen.1009431.].

Whole-exome sequencing study identifies four novel gene loci associated with diabetic kidney disease

Diabetic kidney disease (DKD) is recognized as an important public health challenge. However, its genomic mechanisms are poorly understood. To identify rare variants for DKD, we conducted a whole-exome sequencing (WES) study leveraging large cohorts well-phenotyped for chronic kidney disease and diabetes. Our two-stage WES study included 4372 European and African ancestry participants from the Chronic Renal Insufficiency Cohort and Atherosclerosis Risk in Communities studies (stage 1) and 11 487 multi-ancestry Trans-Omics for Precision Medicine participants (stage 2). Generalized linear mixed models, which accounted for genetic relatedness and adjusted for age, sex and ancestry, were used to test associations between single variants and DKD. Gene-based aggregate rare variant analyses were conducted using an optimized sequence kernel association test implemented within our mixed model framework. We identified four novel exome-wide significant DKD-related loci through initiating diabetes. In single-variant analyses, participants carrying a rare, in-frame insertion in the DIS3L2 gene (rs141560952) exhibited a 193-fold increased odds [95% confidence interval (CI): 33.6, 1105] of DKD compared with noncarriers (P = 3.59 × 10-9). Likewise, each copy of a low-frequency KRT6B splice-site variant (rs425827) conferred a 5.31-fold higher odds (95% CI: 3.06, 9.21) of DKD (P = 2.72 × 10-9). Aggregate gene-based analyses further identified ERAP2 (P = 4.03 × 10-8) and NPEPPS (P = 1.51 × 10-7), which are both expressed in the kidney and implicated in renin-angiotensin-aldosterone system modulated immune response. In the largest WES study of DKD, we identified novel rare variant loci attaining exome-wide significance. These findings provide new insights into the molecular mechanisms underlying DKD.

Combined hyperspectral imaging, monolayer stress microscopy, and S8 image analysis approaches for simultaneously interrogating cellular signals and biomechanics

Second messenger signals, e.g., Ca2+ and cyclic nucleotides, orchestrate a wide range of cellular events. The methods by which second messenger signals determine specific physiological responses are complex. Recent studies point to the importance of temporal and spatial encoding in determining signal specificity. Studies also indicate the importance of mechanical stimuli, substrate stiffness, and mechanical responses - the "mechanosome" - in regulating physiology. Hence, approaches that probe both chemical and mechanical signals are needed. Here, we report preliminary efforts to combine hyperspectral imaging for second messenger signal measurements, monolayer stress microscopy for mechanical force measurements, and S8 analysis software for quantifying localized signals - specifically, Ca2+ dynamics and mechanical forces in human airway smooth muscle cells (HASMCs). HASMCs were prepared as confluent monolayers on 11 kPa gels with embedded fluorescent microparticles that serve as fiducial markers as well as smaller microparticles to measure deformation (strain). Imaging was performed using a custom excitation-scanning hyperspectral microscope. Hyperspectral images were unmixed to identify signals from cellular fluorescent labels (e.g., CAL 590-AM) and fluorescent microparticles. Images were analyzed to quantify localized force dynamics through monolayer stress microscopy. S8 software was used to identify, track, and quantify spatially-localized Ca2+ activity. Results indicate that localized and transient cellular signals and forces can be quantified and mapped within cell populations. Importantly, these results establish a method for simultaneous interrogation of cellular signals and mechanical forces that may play synergistic roles in regulating downstream cellular physiology in confluent monolayers. This work was supported by NIH P01HL066299, R01HL137030, R01HL058506, and NSF MRI1725937. Drs. Leavesley and Rich disclose financial interest in a university start-up company, SpectraCyte LLC, to commercialize spectral imaging technologies.

Aging, prevalence and risk factors of MRI-visible enlarged perivascular spaces

BACKGROUND AND PURPOSE

Cerebral small vessel disease (CSVD) increases with age and is associated with stroke and cognitive decline. Enlarged Perivascular Spaces (ePVS) is an emerging marker of CSVD, but its prevalence over the life span remain unclear. We characterized the age and sex-specific prevalence of ePVS and relation to age-specific risk factors, in a large community-based sample.

METHODS

We included 3,710 Framingham Heart Study participants with available brain MRI (average age 61.4±14.6, 46% men). ePVS burden was rated in the centrum semiovale (CSO) and basal ganglia (BG) regions. Individual vascular risk factors were related to ePVS burden in the CSO, BG, and mixed CSO-BG regions using multivariable adjusted ordinal logistic regression analysis.

RESULTS

Severe ePVS prevalence increased with age in men and women, and paralleled increase in vascular risk factors, and prevention treatment use. Older age, hypertension (and resulting higher treatment use), higher systolic and diastolic blood pressure, and smoking were associated with higher burden of ePVS in the CSO, BG and mixed regions.

CONCLUSIONS

Our observations reinforce the hypothesis that ePVS may be a marker of aging-driven brain vascular pathologies, and its association with vascular risk factors support their role as CSVD imaging biomarker.

Better Understanding of the Metamorphosis of Pregnancy (BUMP): protocol for a digital feasibility study in women from preconception to postpartum

The Better Understanding the Metamorphosis of Pregnancy (BUMP) study is a longitudinal feasibility study aimed to gain a deeper understanding of the pre-pregnancy and pregnancy symptom experience using digital tools. The present paper describes the protocol for the BUMP study. Over 1000 participants are being recruited through a patient provider-platform and through other channels in the United States (US). Participants in a preconception cohort (BUMP-C) are followed for 6 months, or until conception, while participants in a pregnancy cohort (BUMP) are followed into their fourth trimester. Participants are provided with a smart ring, a smartwatch (BUMP only), and a smart scale (BUMP only) alongside cohort-specific study apps. Participant centric engagement strategies are used that aim to co-design the digital approach with participants while providing knowledge and support. The BUMP study is intended to lay the foundational work for a larger study to determine whether participant co-designed digital tools can be used to detect, track and return multimodal symptoms during the perinatal window to inform individual level symptom trajectories.

Restricted Intimal Ca2+ Signaling Associated With Cardiovascular Disease

Endothelial dysfunction is a key feature of cardiovascular disease (CVD) including atherosclerosis. Impaired endothelial signaling leads to plaque formation, vascular wall remodeling and widespread cardiovascular dysregulation. The specific changes along the vascular intima associated with atherosclerosis, including the vulnerable circulation downstream of the flow obstruction, remain poorly understood. Previous findings from animal models suggest that preservation of a distinct Ca2+ signaling profile along the arterial endothelial network is crucial for maintaining vasculature homeostasis and preventing arterial disease. Ca2+ signaling in the intact human artery intima has not been well characterized. Here, we employed confocal imaging and a custom analysis algorithm to assess the spatially and temporally dynamic Ca2+ signaling profiles of human peripheral arteries isolated from the amputated legs of patients with advanced CVD (peripheral artery disease and/or diabetes) or patients who had lost limbs due to non-cardiovascular trauma. In all tibial artery branches (0.5-5 mm diameter) assessed, the intima consistently elicited a broad range of basal Ca2+ signals ranging from isolated focal transients to broad waves. Arteries from patients with existing CVD displayed a restricted intimal Ca2+ signaling pattern characterized by diminished event amplitude and area. Stimulation of type-4 vanilloid transient receptor potential channels (TRPV4) amplified endothelial Ca2+ signals; however, these signals remained smaller and spatially confined in arteries from patients with CVD verses those without CVD. Our findings reveal a characteristic underlying basal Ca2+ signaling pattern within the intima of human peripheral arteries and suggest a distinct truncation of the inherent Ca2+ profile with CVD.

Gene electrotransfer of FGF2 enhances collagen scaffold biocompatibility

Tendon injuries are a common athletic injury that have been increasing in prevalence. While there are current clinical treatments for tendon injuries, they have relatively long recovery times and often do not restore native function of the tendon. In the current study, gene electrotransfer (GET) parameters for delivery to the skin were optimized with monophasic and biphasic pulses with reporter and effector genes towards optimizing underlying tendon healing. Tissue twitching and damage, as well as gene expression and distribution were evaluated. Bioprinted collagen scaffolds, mimicking healthy tendon structure were then implanted subcutaneously for biocompatibility and angiogenesis analyses when combined with GET to accelerate healing. GET of human fibroblast FGF2 significantly increased angiogenesis and biocompatibility of the bioprinted implants when compared to implant only sites. The combination of bioprinted collagen fibers and angiogenic GET therapy may lead to better graft biocompatibility in tendon repair.

Cardioporation enhances myocardial gene expression in rat heart

Damage from myocardial infarction (MI) and subsequent heart failure are serious public health concerns. Current clinical treatments and therapies to treat MI damage largely do not address the regeneration of cardiomyocytes. In a previous study, we established that it is possible to promote regeneration of cardiac muscle with vascular endothelial growth factor B gene delivery directly to the ischemic myocardium. In the current study we aim to optimize cardioporation parameters to increase expression efficiency by varying electrode configuration, applied voltage, pulse length, and plasmid vector size. By using a surface monopolar electrode, optimized pulsing conditions and reducing vector size, we were able to prevent ventricular fibrillation, increase survival, reduce tissue damage, and significantly increase gene expression levels.

Genetically predicted circulating levels of copper and zinc are associated with osteoarthritis but not with rheumatoid arthritis

OBJECTIVE

Osteoarthritis (OA) and rheumatoid arthritis (RA) are both debilitating diseases that cause significant morbidity and disability globally. This study aims to investigate the causal effects of varying blood levels of five minerals -- iron, zinc, copper, calcium, and magnesium, on OA and RA.

DESIGN

We performed two-sample Mendelian randomization (MR) analyses to assess the associations of five circulating minerals with OA and RA. Single nucleotide polymorphisms (SNPs) serving as genetic instruments for the circulating mineral levels were selected from large genome-wide association studies of European-descent individuals. The associations of these SNPs with OA and RA were evaluated in UK Biobank participants. Multiple sensitivity analyses were applied to detect and correct for the presence of pleiotropy.

RESULTS

Genetically determined copper and zinc status were associated with OA, but not with RA. Per standard deviation (SD) increment in copper increases the risk of OA (OR = 1.07, 95% CI: 1.02-1.13) and one of its subtypes, localized OA (OR = 1.08, 95% CI: 1.03-1.15). Per SD increment in zinc is positively associated with risks of OA (OR = 1.07, 95% CI: 1.01-1.13), generalized OA (OR = 1.18, 95% CI: 1.05-1.31), and unspecified OA (OR = 1.21, 95% CI: 1.11-1.31). Additionally, per SD increment in calcium decreases the risk of localized OA (OR = 0.83, 95% CI: 0.69-0.98).

CONCLUSIONS

Genetically high zinc and copper status were positively associated with OA, but not with RA. Given the modifiable nature of circulating mineral status, these findings warrant further investigation for OA prevention strategies.

Genetic Variants Modifying the Triglycerides-Lowering Effect of Fish Oil Supplementation: A Genome-Wide Interaction Study

Objectives

To identify genetic variants that modify the effect of fish oil supplementation on blood lipids, including low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol, and triglycerides.

Methods

We performed a genome-wide interaction study in 73,962 participants of European ancestry from the UK Biobank. Candidate associations were evaluated in a replication study with 7,284 participants from the Atherosclerosis Risk in Communities (ARIC) Study. Meta-analysis was further performed across the two cohorts.

Results

Four novel interaction loci were identified at genome-wide significance in meta-analysis. The lead variant in the GJB6-GJB2-GJA3 gene cluster, rs112803755 (A > G; minor allele frequency = 0.041), shows an interaction effect but not the main effect, suggesting that it would not have been discovered in a typical association study. Fish oil supplementation is associated with a decreased blood level of triglycerides in individuals carrying the minor allele, but with an increased level in homozygotes of the major allele. This locus is significantly associated with higher GJB2 expression of connexin 26 in adipose tissue, while connexin activity is known to change upon exposure to omega-3 fatty acids. Significant interaction effects were also found in three other loci in the genes SLC12A3 (HDL-C), ABCA6 (LDL-C), and MLXIPL (LDL-C), but highly significant main effects are also present.

Conclusions

Our study identifies novel interaction effects for four genetic loci and highlights genetic variants in the GJB6-GJB2-GJA3 gene cluster, which modify the effects of fish oil supplementation on lowering blood triglycerides. These findings highlight the need and possibility for personalized nutrition.

Funding Sources

The University of Georgia Research Foundation

Shared and Unique Clinical Effects of Five Circulating Minerals: A Comparative Phenome-Wide Mendelian-Randomization Study

Objectives

To disentangle the shared and unique causal clinical effects of five circulating minerals – iron, zinc, copper, calcium, and magnesium.

Methods

Genetic instruments for circulating minerals were curated from existing genome-wide association studies. Candidate clinical outcomes were identified with a phenome-wide association study (PheWAS) between these genetic instruments and 853 phenotypes in 310,999 individuals from the UK Biobank. Two-sample Mendelian Randomization (MR) analyses were performed to evaluate the causal associations between genetically predicted circulating mineral levels and candidate clinical outcomes. Multiple sensitivity tests were applied to detect and correct for the presence of horizontal pleiotropy.

Results

Iron and copper were found to share the most clinical outcomes. Genetically predicted higher blood levels of iron and copper are associated with lower risks of iron deficiency anemia and lipid metabolism disorders, including hyperlipidemia and hypercholesterolemia. Consistently, they are also associated with lower blood levels of total cholesterol and low-density lipoprotein cholesterol. On the other hand, osteoarthrosis (OA) and its subcategories are associated with the most minerals, including zinc, copper, and calcium. Genetically predicted higher blood levels of zinc and copper are associated with increased risk of OA, while calcium exhibits protective effects. Another five shared clinical effects were identified. For instance, zinc and magnesium are associated with a higher risk of bacterial infection; calcium and magnesium increase the risk of renal colic; iron increases while calcium decreases the risk of varicose veins. Unique clinical effects of each blood mineral were also pinpointed, such as iron enhancing the risk of glossitis and acquired foot deformities.

Conclusions

Our comparative PheWAS-MR study of five circulating minerals comprehensively characterized their shared and unique clinical effects, highlighting the causal roles of specific minerals in hyperlipidemia and OA. Our findings emphasize managing blood minerals, probably through dietary adjustments, for disease prevention.

Funding Sources

United States Department of Agriculture; National Institute of Food and Agriculture Hatch Funds; Allen Foundation Inc.; University of Georgia Research Foundation.

Abstract MP08: Whole Exome Sequencing Study Identified A Novel Variant For Kidney Function And Progression Of Chronic Kidney Disease

Introduction: Most genetic variants for chronic kidney disease (CKD) have been identified in non-coding regions, with functional roles that are difficult to interpret.

Hypothesis: A whole exome sequencing study focusing on coding variants will reveal novel mechanisms of kidney function and CKD.

Methods: We performed whole exome sequencing analyses of cystatin C among 29,789 UK Biobank (UKB) participants with further confirmation among 4,297 white and 607 African American participants of the Health and Retirement Study (HRS). Conditional analyses for loci achieving exome-wide significance ( P <3.5х10 -7 ) were conducted in UKB using both the exome (n=29,789) and imputed GWAS data (n=295,122). Genomic findings were tested for relevance to baseline estimated glomerular filtration rate (eGFR) and stringently adjudicated CKD progression events among participants of the Chronic Renal Insufficiency Cohort (CRIC) by race and smoking status, using a base model and a full model ( Table ).

Results: We identified a common missense variant, CST9 rs2983640, in a previously reported locus ( CST3 intron rs13038305), of which the minor G allele was associated with lower serum cystatin C level (UKB: beta=-0.03 mg/L, P =7.64х10 -92 ; HRS whites: beta=-0.05 mg/L, P =4.71х10 -6 ; HRS African Americans: beta=-0.03 mg/L, P =0.64; and multi-ethnic meta-analysis beta=-0.03 mg/L, P =2.46х10 -91 ). After controlling for the CST3 variant, the G allele was associated with higher cystatin C level (UKB exome: beta=0.003 mg/L, P =0.04; UKB GWAS: beta=0.003 mg/L, P =1.47х10 -10 ). Similar associations were identified in white CRIC participants (direct effect: beta=-0.05 mg/L, P =0.005; conditional effect: beta=0.004 mg/L, P =0.86). The CST9 rs2983640 G allele was associated with lower baseline eGFR (base model beta=-0.33 ml/min/1.73 m 2 , P =1.98х10 -6 ) and higher hazard of developing CKD progression independent of the reported CST3 variant ( Table ).

Conclusions: We identified a novel missense variant influencing cystatin C level and CKD progression.

Monopolar gene electrotransfer enhances plasmid DNA delivery to skin

A novel monopolar electroporation system and methodologies were developed for in vivo electroporation intended for potential clinical applications such as gene therapy. We hypothesized that an asymmetric anode/cathode electrode applicator geometry could produce favorable electric fields for electroporation, without the typical drawback associated with traditional needle and parallel plate geometries. Three monopolar electrode applicator prototypes were built and tested for gene delivery of reporter genes to the skin in a guinea pig model. Gene expression was evaluated in terms of kinetics over time and expression distribution within the treatment site. Different pulsing parameters, including pulse amplitude, pulse duration, and pulse number were evaluated. Monopolar gene electrotransfer significantly enhanced gene expression compared to controls over the course of 21 days. Gene expression distribution was observed throughout the full thickness of the epidermis, as well as notable expression in the deeper layers of the skin, including the dermis, and the underlying striated muscle without any damage at the treatment site, which is a substantial improvement over previously reported expression confined to the epidermis only. Expression distribution observed is consistent with the electric field distribution model, indicating that our novel electrode geometry results in targeted electroporation and gene transfer. This is important, as it may facilitate translation of many electroporation-based clinical therapies including gene therapies, IRE, and ECT.

The effects of recombinant human insulin-like growth factor-1/insulin-like growth factor binding protein-3 administration on lipid and carbohydrate metabolism in recreational athletes

OBJECTIVE

Previous studies suggested that recombinant human IGF-1 (rhIGF-1) administration affects carbohydrate and lipid metabolism in healthy people and in people with diabetes. This study aimed to determine the effects of rhIGF-1/rhIGF binding protein-3 (rhIGFBP-3) administration on glucose homeostasis and lipid metabolism in healthy recreational athletes.

DESIGN AND SETTING

Randomized, double-blind, placebo-controlled rhIGF-1/rhIGFBP-3 administration study at Southampton General Hospital, UK.

PARTICIPANTS

56 recreational athletes (30 men, 26 women).

METHODS

Participants were randomly assigned to receive placebo, low-dose rhIGF-1/rhIGFBP-3 (30 mg/day) or high-dose rhIGF-1/rhIGFBP-3 (60 mg/day) for 28 days. The following variables were measured before and immediately after the treatment period: fasting lipids, glucose, insulin, C-peptide and glycated haemoglobin. The homeostatic model assessment (HOMA-IR) was used to estimate insulin sensitivity and indirect calorimetry to assess substrate oxidation rates. The general linear model approach was used to compare treatment group changes with the placebo group.

RESULTS

Compared with the placebo group, there was a significant reduction in fasting triglycerides in participants treated with high-dose rhIGF-1/rhIGFBP-3 (p = .030), but not in the low-dose group (p = .390). In women, but not in men, there were significant increases in total cholesterol (p = .003), HDL cholesterol (p = .001) and LDL cholesterol (p = .008). These lipid changes were associated with reduced fasting insulin (p = .010), C-peptide (p = .001) and HOMA-IR (p = .018) in women and reduced C-peptide (p = .046) in men.

CONCLUSIONS

rhIGF-1/rhIGFBP-3 administration for 28 days reduced insulin concentration, improved insulin sensitivity and had significant effects on lipid profile including decreased fasting triglycerides.

A216 CLINICAL MANIFESTATIONS OF LYSOSOMAL ACID LIPASE DEFICIENCY (LAL-D): THE INTERNATIONAL LAL-D REGISTRY

Background

Lysosomal acid lipase deficiency (LAL-D) is a rare, autosomal recessive disease caused by pathogenic variants in the LIPA gene. Lysosomal accumulation of cholesteryl esters and triglycerides leads to cirrhosis and dyslipidemia across a clinical spectrum, and affect both infants and children/adults.

Aims

An international registry (NCT01633489; Alexion Pharmaceuticals, Inc.; 2013–ongoing) was established to better understand the natural history of lysosomal acid lipase deficiency (LAL-D) and to evaluate long-term treatment outcomes.

Methods

Baseline findings for patients enrolled through July 1, 2019 are presented. Of 190 patients enrolled, 35 were excluded from this analysis (LIPA carrier, deceased at enrollment, unconfirmed LAL-D diagnosis); 155 patients with confirmed LAL-D diagnosis were included (12 infants, 143 children/adults). LAL enzyme activity analysis was performed for 145/154 patients (94%) and genetic testing for 128/154 patients (83%).

Results

Of 105 children/adults with reported LIPA mutations, 39 were homozygous and 34 were compound heterozygous for the common LIPA mutation E8SJM (c.894G&gt;A); 6 infants with reported LIPA mutations were homozygotes and 2 were compound heterozygotes. Of the 155 patients, 62% were &lt;18 years, 52% were male, and 85% were white. Median (range) age at clinical onset was 0.2 years (0.0–0.7) among infants and 6.0 years (0.0–41.3) among 133 children/adults with data; median (range) age at diagnosis was 0.2 years (−0.1 to 1.2) among infants and 10.8 years (0.2–53.6) among 135 children/adults with data. Manifestations that raised suspicion of LAL-D were reported in 149/155 patients. Infants (12 with data) presented predominantly with hepatomegaly (75%), splenomegaly (58%), nausea/vomiting (58%), and diarrhea (50%), and 50% had a known family history of LAL-D. Children/adults (n=143) presented predominantly with elevated alanine aminotransferase levels (67%), hepatomegaly (66%), and elevated aspartate aminotransferase levels (65%). Of 74 children/adults with baseline liver biopsy, 58% had microvesicular steatosis, 16% had micro- and macrovesicular steatosis, and 32% had lobular inflammation. Of the 155 patients, 6% had a medical history of cirrhosis. Analyses exploring the genotype-phenotype relationship will be presented.

Conclusions

Registry data of &gt;150 LAL-D patients demonstrate early symptom onset, variable clinical manifestations, and a significant diagnostic delay in children/adults.

Funding Agencies

Alexion Pharmaceuticals, Inc.

Genome-wide association study of fish oil supplementation on lipid traits in 81,246 individuals reveals new gene-diet interaction loci

Fish oil supplementation is widely used for reducing serum triglycerides (TAGs) but has mixed effects on other circulating cardiovascular biomarkers. Many genetic polymorphisms have been associated with blood lipids, including high- and low-density-lipoprotein cholesterol (HDL-C, LDL-C), total cholesterol, and TAGs. Here, the gene-diet interaction effects of fish oil supplementation on these lipids were analyzed in a discovery cohort of up to 73,962 UK Biobank participants, using a 1-degree-of-freedom (1df) test for interaction effects and a 2-degrees-of-freedom (2df) test to jointly analyze interaction and main effects. Associations with P < 1×10-6 in either test (26,157; 18,300 unique variants) were advanced to replication in up to 7,284 participants from the Atherosclerosis Risk in Communities (ARIC) Study. Replicated associations reaching 1df P < 0.05 (2,175; 1,763 unique variants) were used in meta-analyses. We found 13 replicated and 159 non-replicated (UK Biobank only) loci with significant 2df joint tests that were predominantly driven by main effects and have been previously reported. Four novel interaction loci were identified with 1df P < 5×10-8 in meta-analysis. The lead variant in the GJB6-GJB2-GJA3 gene cluster, rs112803755 (A>G; minor allele frequency = 0.041), shows exclusively interaction effects. The minor allele is significantly associated with decreased TAGs in individuals with fish oil supplementation, but with increased TAGs in those without supplementation. This locus is significantly associated with higher GJB2 expression of connexin 26 in adipose tissue; connexin activity is known to change upon exposure to omega-3 fatty acids. Significant interaction effects were also found in three other loci in the genes SLC12A3 (HDL-C), ABCA6 (LDL-C), and MLXIPL (LDL-C), but highly significant main effects are also present. Our study identifies novel gene-diet interaction effects for four genetic loci, whose effects on blood lipids are modified by fish oil supplementation. These findings highlight the need and possibility for personalized nutrition.

An open label, randomised controlled trial of rifapentine versus rifampicin based short course regimens for the treatment of latent tuberculosis in England: the HALT LTBI pilot study

BACKGROUND

Ending the global tuberculosis (TB) epidemic requires a focus on treating individuals with latent TB infection (LTBI) to prevent future cases. Promising trials of shorter regimens have shown them to be effective as preventative TB treatment, however there is a paucity of data on self-administered treatment completion rates. This pilot trial assessed treatment completion, adherence, safety and the feasibility of treating LTBI in the UK using a weekly rifapentine and isoniazid regimen versus daily rifampicin and isoniazid, both self-administered for 12 weeks.

METHODS

An open label, randomised, multi-site pilot trial was conducted in London, UK, between March 2015 and January 2017. Adults between 16 and 65 years with LTBI at two TB clinics who were eligible for and agreed to preventative therapy were consented and randomised 1:1 to receive either a weekly combination of rifapentine/isoniazid ('intervention') or a daily combination of rifampicin/isoniazid ('standard'), with both regimens taken for twelve weeks; treatment was self-administered in both arms. The primary outcome, completion of treatment, was self-reported, defined as taking more than 90% of prescribed doses and corroborated by pill counts and urine testing. Adverse events were recorded.

RESULTS

Fifty-two patients were successfully enrolled. In the intervention arm 21 of 27 patients completed treatment (77.8, 95% confidence interval [CI] 57.7-91.4), compared with 19 of 25 (76.0%, CI 54.9-90.6) in the standard of care arm. There was a similar adverse effect profile between the two arms.

CONCLUSION

In this pilot trial, treatment completion was comparable between the weekly rifapentine/isoniazid and the daily rifampicin/isoniazid regimens. Additionally, the adverse event profile was similar between the two arms. We conclude that it is safe and feasible to undertake a fully powered trial to determine whether self-administered weekly treatment is superior/non-inferior compared to current treatment.

TRIAL REGISTRATION

The trial was funded by the NIHR, UK and registered with ISRCTN ( 26/02/2013-No.04379941 ).

SETD1 and NF-κB Regulate Periodontal Inflammation through H3K4 Trimethylation

The inflammatory response to periodontal pathogens is dynamically controlled by the chromatin state on inflammatory gene promoters. In the present study, we have focused on the effect of the methyltransferase SETD1B on histone H3 lysine K4 (H3K4) histone trimethylation on inflammatory gene promoters. Experiments were based on 3 model systems: 1) an in vitro periodontal ligament (PDL) cell culture model for the study of SETD1 function as it relates to histone methylation and inflammatory gene expression using Porphyromonas gingivalis lipopolysaccharide (LPS) as a pathogen, 2) a subcutaneous implantation model to determine the relationship between SETD1 and nuclear factor κB (NF-κB) through its activation inhibitor BOT-64, and 3) a mouse periodontitis model to test whether the NF-κB activation inhibitor BOT-64 reverses the inflammatory tissue destruction associated with periodontal disease. In our PDL progenitor cell culture model, P. gingivalis LPS increased H3K4me3 histone methylation on IL-1β, IL-6, and MMP2 gene promoters, while SETD1B inhibition decreased H3K4me3 enrichment and inflammatory gene expression in LPS-treated PDL cells. LPS also increased SETD1 nuclear localization in a p65-dependent fashion and the nuclear translocation of p65 as mediated through SETD1, suggestive of a synergistic effect between SETD1 and p65 in the modulation of inflammation. Confirming the role of SETD1 in p65-mediated periodontal inflammation, BOT-64 reduced the number of SETD1-positive cells in inflamed periodontal tissues, restored periodontal tissue integrity, and enhanced osteogenesis in a periodontal inflammation model in vivo. Together, these results have established the histone lysine methyltransferase SETD1 as a key factor in the opening of the chromatin on inflammatory gene promoters through histone H3K4 trimethylation. Our studies also confirmed the role of BOT-64 as a potent molecular therapeutic for the restoration of periodontal health through the inhibition of NF-κB activity and the amelioration of SETD1-induced chromatin relaxation.

Histone Methylation: Achilles Heel and Powerful Mediator of Periodontal Homeostasis

The packaging of DNA around nucleosomes exerts dynamic control over eukaryotic gene expression either by granting access to the transcriptional machinery in an open chromatin state or by silencing transcription via chromatin compaction. Histone methylation modification affects chromatin through the addition of methyl groups to lysine or arginine residues of histones H3 and H4 by means of histone methyl transferases or histone demethylases. Changes in histone methylation state modulate periodontal gene expression and have profound effects on periodontal development, health, and therapy. At the onset of periodontal development, progenitor cell populations such as dental follicle cells are characterized by an open H3K4me3 chromatin mark on RUNX2, MSX2, and DLX5 gene promoters. During further development, periodontal progenitor differentiation undergoes a global switch from the H3K4me3 active methyl mark to the H3K27me3 repressive mark. When compared with dental pulp cells, periodontal neural crest lineage differentiation is characterized by repressive H3K9me3 and H3K27me3 marks on typical dentinogenesis-related genes. Inflammatory conditions as they occur during periodontal disease result in unique histone methylation signatures in affected cell populations, including repressive H3K9me3 and H3K27me3 histone marks on extracellular matrix gene promoters and active H3K4me3 marks on interleukin, defensin, and chemokine gene promoters, facilitating a rapid inflammatory response to microbial pathogens. The inflammation-induced repression of chromatin on extracellular matrix gene promoters presents a therapeutic opportunity for the application of histone methylation inhibitors capable of inhibiting suppressive trimethylation marks. Furthermore, inhibition of chromatin coregulators through interference with key inflammatory mediators such as NF-kB by means of methyltransferase inhibitors provides another avenue to halt the exacerbation of the inflammatory response in periodontal tissues. In conclusion, histone methylation dynamics play an intricate role in the fine-tuning of chromatin states during periodontal development and harbor yet-to-be-realized potential for the treatment of periodontal disease.

The Causal Effects of Blood Iron and Copper on Lipid Metabolism Diseases: Evidence from Phenome-Wide Mendelian Randomization Study

Blood levels of iron and copper, even within their normal ranges, have been associated with a wide range of clinical outcomes. The available epidemiological evidence for these associations is often inconsistent and suffers from confounding and reverse causation. This study aims to examine the causal clinical effects of blood iron and copper with Mendelian randomization (MR) analyses. Genetic instruments for the blood levels of iron and copper were curated from existing genome-wide association studies. Candidate clinical outcomes were identified based on a phenome-wide association study (PheWAS) between these genetic instruments and a wide range of phenotypes in 310,999 unrelated individuals of European ancestry from the UK Biobank. All signals passing stringent correction for multiple testing were followed by MR analyses, with replication in independent data sources where possible. We found that genetically predicted higher blood levels of iron and copper are both associated with lower risks of iron deficiency anemia (odds ratio (OR) = 0.75, 95% confidence interval (CI): 0.67-0.85, p = 1.90 × 10-6 for iron; OR = 0.88, 95% CI: 0.78-0.98, p = 0.032 for copper), lipid metabolism disorders, and its two subcategories, hyperlipidemia (OR = 0.90, 95% CI: 0.85-0.96, p = 6.44 × 10-4; OR = 0.92, 95% CI: 0.87-0.98, p = 5.51 × 10-3) and hypercholesterolemia (OR = 0.90, 95% CI: 0.84-0.95, p = 5.34 × 10-4; OR = 0.93, 95% CI: 0.89-0.99, p = 0.022). Consistently, they are also associated with lower blood levels of total cholesterol and low-density lipoprotein cholesterol. Multiple sensitivity tests were applied to assess the presence of pleiotropy and the robustness of causal estimates. Regardless of the approaches, consistent evidence was obtained. Moreover, the unique clinical effects of each blood mineral were identified. Notably, genetically predicated higher blood iron is associated with an enhanced risk of varicose veins (OR = 1.28, 95% CI: 1.15-1.42, p = 4.34 × 10-6), while blood copper is positively associated with the risk of osteoarthrosis (OR = 1.07, 95% CI: 1.02-1.13, p = 0.010). Sex-stratified MR analysis further revealed some degree of sex differences in their clinical effects. Our comparative PheWAS-MR study of iron and copper comprehensively characterized their shared and unique clinical effects, highlighting their potential causal roles in hyperlipidemia and hypercholesterolemia. Given the modifiable nature of blood mineral status and the potential for clinical intervention, these findings warrant further investigation.

RIFM fragrance ingredient safety assessment, ethyl (E)hex-3-enoate, CAS registry number 26553-46-8

The existing information supports the use of this material as described in this safety assessment. Ethyl (E)hex-3-enoate was evaluated for genotoxicity, repeated dose toxicity, reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, and environmental safety. Data from read-across analog methyl 3-hexenoate (CAS # 2396-78-3) show that ethyl (E)hex-3-enoate is not expected to be genotoxic. The repeated dose, reproductive, and local respiratory toxicity endpoints were evaluated using the Threshold of Toxicological Concern (TTC) for a Cramer Class I material, and the exposure to ethyl (E)hex-3-enoate is below the TTC (0.03 mg/kg/day, 0.03 mg/kg/day, and 1.4 mg/day, respectively). The skin sensitization endpoint was completed using Dermal Sensitization Threshold (DST) for non-reactive materials (900 μg/cm²); exposure is below the DST. The phototoxicity/photoallergenicity endpoints were evaluated based on ultraviolet (UV) spectra; ethyl (E)hex-3-enoate is not expected to be phototoxic/photoallergenic. The environmental endpoints were evaluated; ethyl (E)hex-3-enoate was found not to be persistent, bioaccumulative, and toxic (PBT) as per the International Fragrance Association (IFRA) Environmental Standards, and its risk quotients, based on its current Volume of Use in Europe and North America (i.e., Predicted Environmental Concentration/Predicted No Effect Concentration [PEC/PNEC]), are <1.

RIFM fragrance ingredient safety assessment, 2-acetylthiazole, CAS Registry Number 24295-03-2

The existing information supports the use of this material as described in this safety assessment. 2-Acetylthiazole was evaluated for genotoxicity, repeated dose toxicity, reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, and environmental safety. Data show that 2-acetylthiazole is not genotoxic. The skin sensitization endpoint was completed using the dermal sensitization threshold (DST) for non-reactive materials (900 μg/cm²); exposure is below the DST. The repeated dose, reproductive, and local respiratory toxicity endpoints were evaluated using the threshold of toxicological concern (TTC) for a Cramer Class II material, and the exposure to 2-acetylthiazole is below the TTC (0.009 mg/kg/day, 0.009 mg/kg/day, and 0.47 mg/day, respectively). The phototoxicity/photoallergenicity endpoints were evaluated based on UV spectra; 2-acetylthiazole is not expected to be phototoxic/photoallergenic. The environmental endpoints were evaluated, 2-acetylthiazole was found not to be persistent, bioaccumulative, and toxic (PBT) as per the International Fragrance Association (IFRA) Environmental Standards, and its risk quotients, based on its current Volume of Use in Europe and North America (i.e., Predicted Environmental Concentration/Predicted No Effect Concentration [PEC/PNEC]) are <1.

RIFM fragrance ingredient safety assessment, 3-(4-methyl-3-pentenyl)-3-cyclohexene-1-carbonitrile, CAS registry number 68084-04-8

The existing information supports the use of this material as described in this safety assessment. 3-(4-Methyl-3-pentenyl)-3-cyclohexene-1-carbonitrile was evaluated for genotoxicity, repeated dose toxicity, reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, and environmental safety. Data show that 3-(4-methyl-3-pentenyl)-3-cyclohexene-1-carbonitrile is not genotoxic. Data show that there are no safety concerns for 3-(4-methyl-3-pentenyl)-3-cyclohexene-1-carbonitrile for skin sensitization under the current declared levels of use. The repeated dose, reproductive, and local respiratory toxicity endpoints were evaluated using the threshold of toxicological concern (TTC) for a Cramer Class III material, and the exposure to 3-(4-methyl-3-pentenyl)-3-cyclohexene-1-carbonitrile is below the TTC (0.0015 mg/kg/day, 0.0015 mg/kg/day, and 0.47 mg/day, respectively). The phototoxicity/photoallergenicity endpoints were evaluated based on UV spectra; 3-(4-methyl-3-pentenyl)-3-cyclohexene-1-carbonitrile is not expected to be phototoxic/photoallergenic. The environmental endpoints were evaluated, 3-(4-methyl-3-pentenyl)-3-cyclohexene-1-carbonitrile was found not to be persistent, bioaccumulative, and toxic (PBT) as per the International Fragrance Association (IFRA) Environmental Standards, and its risk quotients, based on its current Volume of Use in Europe and North America (i.e., Predicted Environmental Concentration/Predicted No Effect Concentration [PEC/PNEC]) are <1.

RIFM fragrance ingredient safety assessment, ethyl 3-methylthiopropionate, CAS Registry Number 13327-56-5

The existing information supports the use of this material as described in this safety assessment. Ethyl 3-methylthiopropionate was evaluated for genotoxicity, repeated dose toxicity, reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, and environmental safety. Data from read-across analog methyl 3-methylthiopropionate (CAS # 13532-18-8) show that ethyl 3-methylthiopropionate is not expected to be genotoxic. The repeated dose, reproductive, and local respiratory toxicity endpoints were evaluated using the Threshold of Toxicological Concern (TTC) for a Cramer Class I material, and the exposure to ethyl 3-methylthiopropionate is below the TTC (0.03 mg/kg/day, 0.03 mg/kg/day, and 1.4 mg/day, respectively). The skin sensitization endpoint was completed using the Dermal Sensitization Threshold (DST) for non-reactive materials (900 μg/cm²); exposure is below the DST. The phototoxicity/photoallergenicity endpoints were evaluated based on ultraviolet (UV) spectra; ethyl 3-methylthiopropionate is not expected to be phototoxic/photoallergenic. The environmental endpoints were evaluated; ethyl 3-methylthiopropionate was found not to be persistent, bioaccumulative, and toxic (PBT) as per the International Fragrance Association (IFRA) Environmental Standards, and its risk quotients, based on its current Volume of Use in Europe and North America (i.e., Predicted Environmental Concentration/Predicted No Effect Concentration [PEC/PNEC]), are <1.

Genomic Characterization of the Zinc Transcriptional Regulatory Element Reveals Potential Functional Roles of ZNF658

The zinc transcriptional regulatory element (ZTRE) is a newly reported binding motif for human zinc finger protein ZNF658, which alters gene expression in response to cellular zinc. The ZTRE has two nucleotide components-the palindromic flanking pairs and the bridging "N" bases between these flanks that range in number from 0 to 100. There are 12 pairs of ZTRE flanks (designated A-L). Three thousand five hundred twenty-five genes contain one or more ZTREs - 1000 to + 200 bp from their transcriptional start site (TSS). ZTRE-E is observed at a greater frequency, and ZTRE containing 25 bridging bases are less frequent, within - 200 bp from the TSS. The genes with ZTREs in this range are enriched in processes that may compensate zinc deficiency, while other genes with ZTREs outside this range are enriched in transcriptional activation processes. The division of ZTREs into two groups may imply a dual role of ZNF658, similar to the homologous yeast protein Zap1, via binding to low or high affinity sequences dependent upon cellular zinc. The KLF/Sp1-family binding motif is prevalent within the ZTRE "N" bridging bases, suggesting ZNF658 may compete with Sp1-like transactivators to suppress transcription.