The global prevalence of premature ovarian insufficiency: a systematic review and meta-analysis

OBJECTIVE

The objective of this review was to answer the global prevalence of premature ovarian insufficiency (POI), and explore the associated factors including etiopathology and regions with POI.

METHODS

The search was conducted on reports from a total of eight databases that comprised Chinese National Knowledge Infrastructure (CNKI), Wanfang, China BioMedical Literature Database (CBM), PubMed, the Cochrane Library, Embase, Web of Science and Ovid MEDLINE^® between 1946 and 2021. To analyze the source of heterogeneity, we performed subgroup analysis based on different etiologies and regions. Meta-analysis was carried out by Stata14.0 software.

RESULTS

The results showed that the global overall prevalence of POI among women was 3.5%. By subgroup analysis, the prevalence of POI among women with iatrogenic etiology was 11.2%, followed by autoimmunity (10.5%); the prevalence of POI by region was 11.3% at the highest in North America followed by South America (5.4%); and the prevalence of POI was 5.3% in a developing country, higher than 3.1% in a developed country. The trend of prevalence of POI over the past 20 years was on the rise (although p > 0.05).

CONCLUSION

We recommend that health and medical institutions strengthen public health awareness, achieve health-education goals related to POI and increase women's awareness of and attention to POI.

Chemical Constituents and Hypoglycemic Mechanisms of Dendrobium nobile in Treatment of Type 2 Diabetic Rats by UPLC-ESI-Q-Orbitrap, Network Pharmacology and In Vivo Experimental Verification

This study aimed to systematically explore the chemical constituents of D. nobile and its hypoglycemic effect by UPLC-ESI-Q-Orbitrap, network pharmacology and in vivo experiment. The chemical constituents of D. nobile were qualitatively analyzed, and the hypoglycemic compounds were quickly identified. Network pharmacological analysis and molecular docking technique were applied to assist in the elucidation of the hypoglycemic mechanisms of D. nobile. A type 2 diabetic mellitus (T2DM) rat model was established using the HFD and STZ method for in vivo experimental verification, and these T2DM rats were treated with D. nobile extract and D. nobile polysaccharide for two months by gavage. The results showed that a total of 39 chemical constituents of D. nobile, including alkaloids, bibenzyls, phenanthrenes and other types of compounds, were identified. D. nobile extract and D. nobile polysaccharide could significantly ameliorate the body weight, hyperglycemia, insulin resistance, dyslipidemia and morphological impairment of the liver and pancreas in the T2DM rats. α-Linolenic acid, dihydroconiferyl dihydro-p-coumarate, naringenin, trans-N-feruloyltyramine, gigantol, moscatilin, 4-O-methylpinosylvic acid, venlafaxine, nordendrobin and tristin were regarded as the key hypoglycemic compounds of D. nobile, along with the hypoglycemic effect on the PI3K-AKT signaling pathway, the insulin signaling pathway, the FOXO signaling pathway, the improvement of insulin resistance and the AGE-RAGE signaling pathway. The Western blotting experiment results confirmed that D. nobile activated the PI3K/AKT pathway and insulin signaling pathway, promoted glycogen synthesis via regulating the expression of glycogen synthase kinase 3 beta (GSK-3β) and glucose transporter 4 (GLUT4), and inhibited liver gluconeogenesis by regulating the expression of phosphoenolpyruvate carboxykinase (PEPCK) and glucose 6 phosphatase (G6pase) in the liver. The results suggested that the hypoglycemic mechanism of D. nobile might be associated with liver glycogen synthesis and gluconeogenesis, contributing to improving insulin resistance and abnormal glucose metabolism in the T2DM rats.

A composite serum biomarker index for the diagnosis of systemic sclerosis interstitial lung disease: a multicentre, observational, cohort study

OBJECTIVE

In patients with systemic sclerosis (SSc), we investigated composite serum biomarker panels for the diagnosis and risk-stratification of SSc-associated interstitial lung disease (SSc-ILD).

METHODS

Twenty-eight biomarkers were analysed in 640 participants: 259 with SSc-ILD and 179 SSc-controls without ILD (Australian Scleroderma Cohort Study), 172 idiopathic pulmonary fibrosis (IPF)-controls (Australian IPF Registry), and 30 healthy controls. A composite index was developed from biomarkers associated with ILD in multivariable analysis derived at empirical thresholds. Performance of the index to identify ILD, and specifically SSc-ILD, and its association with lung function, radiological extent, health-related quality of life (HRQoL) were evaluated in derivation and validation cohorts. Biomarkers to distinguish SSc-ILD from IPF-controls were identified.

RESULTS

A composite biomarker index, comprising SP-D, Ca15-3 and ICAM-1, was strongly associated with SSc-ILD diagnosis, independent of age, sex, smoking and lung function (index=3: pooled adjusted OR 12.72, 95%CI 4.59-35.21, p<0.001). The composite index strengthened the performance of individual biomarkers for SSc-ILD identification. In SSc patients, a higher index was associated with worse baseline disease severity (index=3 relative to index=0: adjusted absolute change in FVC% ^- 17.84% and DLCO% ^- 20.16%, both p<0.001).

CONCLUSION

A composite serum biomarker index, comprising SP-D, Ca15-3 and ICAM-1 may improve the identification and risk-stratification of ILD in SSc patients at baseline.

Assessing the Readiness for Implementing the World Health Organization's ICOPE Approach in Hong Kong: Perspectives from Social Care and Policy Stakeholders

Although integrated care has been considered a key strategy in reforming health systems around the world, it seems hard to realise in practice, particularly in the part of medical social integration. Worse still, little is known about the capacity of social care professionals who implement it, or their perceived roles and responsibilities, as well as the barriers and facilitators that stakeholders from the health and social sectors identify as factors affecting the ICOPE implementation process. Therefore, the present study was performed to probe into these issues. Data were collected from an online survey based on the WHO ICOPE scorecard (N = 34), and focus groups with policy makers, managers, health and social care professionals (N = 47). Inductive analyses were performed in accordance with the service and system levels within the WHO ICOPE implementation framework. While the findings from the scorecard survey highlight the gap in actualizing the ICOPE approach within the existing social services and care structures, we found support for a model of integrated care underpinned by the WHO ICOPE approach. Factors that may hinder and facilitate ICOPE implementation include workforce capacity-building, coordinated networks and partnerships, and financial mechanisms. This finding can help inform subsequent actions that further support health and social care advancement and collaboration, and the implementation of the ICOPE approach.

A Dyadic Cooking-Based Intervention for Improving Subjective Health and Well-Being of Older Adults with Subjective Cognitive Decline and Their Caregivers: A Randomized Controlled Trial

OBJECTIVES

Evidence on the effectiveness of cooking activities as a well-being promotion intervention for older adults with subjective cognitive decline (SCD) and their caregivers is scarce. In view of this, a randomized controlled trial was conducted to examine whether a dyadic cooking-based intervention can improve the subjective health and well-being of older adults with SCD and their caregivers, as well as the cooking competence of the former group.

DESIGN

Randomized controlled trial.

SETTING

Community.

PARTICIPANTS

Sixty pairs of community-dwelling older adults aged 60 years or above with SCD (mean age = 78.4 years) and their caregivers (mean age = 65.3 years) were randomly assigned to the intervention group (N = 30 pairs) and the wait-list control group (N = 30 pairs).

INTERVENTION

The intervention was an innovative 5-week (two hours per week) dyadic cooking-based intervention employing procedural learning methods specifically adapted for older adults with SCD.

MEASUREMENTS

The outcome measures included 1) a well-being index composed by four indicators: life satisfaction, feeling of happiness, sense of purpose and meaning in life, and perceived health, and 2) cooking competence.

RESULTS

For both older adults with SCD and their caregivers, the increases in the well-being index were significantly greater in the intervention group than in the control group (β = 0.508, 95% CI [0.036, 0.980]). For older adults with SCD, the increases in the cooking competence score were significantly greater in the intervention group than in the control group (β = 1.629, 95% CI [0.165, 3.071]).

CONCLUSION

The dyadic cooking-based intervention resulted in improvements in the cooking competence and well-being of older adults with SCD, as well as the well-being of caregivers.

Trajectories of Intrinsic Capacity: Determinants and Associations with Disability

OBJECTIVES

Intrinsic capacity (IC) declines progressively with age, thereby increasing the risk of disability. However, it is less known whether IC trajectories are associated with disability. This study aims to identify the different patterns of IC trajectories in older people, and examine their determinants and associations with Instrumental Activities of Daily Living (IADL).

DESIGN

Cohort study.

SETTING

Community centres in different regions in Hong Kong.

PARTICIPANTS AND MEASUREMENTS

Longitudinal data from community-dwelling older people aged 60 years or above (n = 1371) collected between 2016 and 2021 was analysed. Their mean age was 74.5 years, and 78.7% of them were female. Repeated measurements of a set of 14 self-reported items were used to generate IC scores at four time points using a bi-factor model. Latent class growth analysis was performed to identify classes with distinct IC trajectories. The association between class membership and IADL disability was then examined using logistic regression.

RESULTS

Three distinct IC trajectories were identified. The 1st class included those with the highest level of baseline IC and the least declining trajectory, whereas the 3rd class was composed by those with the lowest level of baseline IC and the most declining trajectory. Older age, female gender, lower perceived financial adequacy, living in public or subsidized housing, and chronic diseases were associated with the 3rd class. After adjusting for demographic factors, socioeconomic status, and the number of chronic diseases, the 1st class was more likely to preserve IADL when compared against the 2nd class, with OR being 3.179 (95% CI: 2.152-4.793), whereas for the 3rd class, the OR was 0.253 (95% CI: 0.178-0.359).

CONCLUSION

Monitoring IC trajectories is of relevance to clinical practice, as it helps shift the focus from treating acute episodes of illness to preserving the functional ability of older people.

Moving towards the ICOPE Approach: Evaluation of Community-Based Intervention Activities on Improving Intrinsic Capacity

OBJECTIVES

Different types of community-based intervention activities may have differential effects in improving the intrinsic capacity (IC) of older people. This study aims to (i) identify subgroups of older people based on their IC impairments, (ii) examine the differential associations between different types of activity participations and change in IC across subgroups, and (iii) assess whether the activity participation patterns of older people align with the way that would benefit them the most.

METHODS

Participants were community-dwelling older people aged 60 years or above. They were screened for IC impairments at baseline, and their participation records of different types (cognitive, physical, nutritional, mental, and social) of intervention activities were collected for one year. An aggregated IC score was created based on four IC domains including cognitive (self-rated memory), locomotor (self-rated difficulties in walking), vitality (self-rated weight loss), and psychological (subjective well-being). Cluster analysis was used to group homogenous participants. Mixed-effects regression was used to examine the associations between activity counts (i.e., number of sessions participated) and change in IC. Activity participation patterns were also compared across subgroups.

RESULTS

Data were obtained from 7,357 participants (mean age = 74.72 years). Four clusters were identified, including those who were relatively robust (cluster 1, N = 4,380, 59.5%), those who had cognitive decline (cluster 2, N = 2,134, 29.0%), those who had impaired mobility and vitality (cluster 3, N = 319, 4.3%), and those with poor psychological well-being (cluster 4, N = 524, 7.1%). Overall, activity count was associated with IC improvement (β = 0.073, 95% CI [0.037, 0.108]). However, as regards the cluster-specific results, different types of activities were associated with IC improvement for different specific clusters. For instance, cognitive activity count was associated with IC improvement only for cluster 2 (β = 0.491, 95% CI [0.258, 0.732]). Notably, none of the activity types were associated with IC improvement for cluster 1. Regarding the activity participation patterns, there were no significant differences across the four clusters (Wilk's Λ = 0.997, F = 1.400, p = .138).

CONCLUSIONS AND IMPLICATIONS

IC improvement depended on the activity types and IC status of older people. In view of this, a people-centred and targeted approach should be adopted to maximize the overall benefits of intervention activities.

DOP76 No durable impact of COVID-19 on disease activity and microbiome composition in patients with IBD

Background

Although patients with inflammatory bowel disease (IBD) reported an increased frequency of gastrointestinal (GI) symptoms following infection, the durable impact of COVID-19 on underlying IBD is not well defined.

Methods

In 118 IBD patients with COVID-19, clinical and endoscopic IBD activity, laboratory markers (ESR, CRP, hemoglobin (Hb), fecal calprotectin(FCP)), and medication utilization was assessed up to 6 months post-infection and compared to during infection or up to 6 months prior to infection. Active disease was defined by a Harvey Bradshaw Index > 4, Mayo Score ≥2, SES-CD ≥2, Mayo endoscopic score ≥1. 16S rRNA analysis was used to evaluate microbiome composition in a subset of 12 patients before and after COVID-19.

Results

Although upper respiratory (86.6%) and new GI symptoms (39.1%) were common in patients with IBD, there was no significant change in IBD clinical disease activity (Pre vs. Post-COVID-19 HBI: 4.7 vs. 4.9; partial Mayo: 3.0 vs. 2.1), endoscopic evaluation (Pre vs. Post-COVID-19 SES-CD: 7.2 vs. 8.9, Mayo endoscopic score: 1.5 vs. 1.7), or laboratory markers (Pre vs. Post-COVID-19 CRP: 1.2 vs. 1.3; ESR: 25 vs. 26; Hb 12.8 vs. 13.2; FCP: 388 vs. 250) up to 7 months post-COVID-19 compared to the 6 months prior to infection (Table 1). Overall active disease was present in 60% of the cohort prior to COVID-19 and 55% and 59% during and post-COVID-19, respectively. More subjects (8.5%) reported a delay in medical therapy during COVID-19, but there were no differences in the need for corticosteroids, a change in medical therapy, or IBD-related surgery or hospitalization during or post-COVID-19 compared to the prior 6 months. Microbiome composition stratified by underlying IBD disease activity, but did not show significant change post-COVID-19 (Figure 1).

Conclusion

COVID-19 showed no durable impact on clinical IBD disease activity or microbiome composition supporting guidelines for continued maintenance care.

Skin protective and regenerative effects of RM191A, a novel superoxide dismutase mimetic

Superoxide dismutase (SOD) is known to be protective against oxidative stress-mediated skin dysfunction. Here we explore the potential therapeutic activities of RM191A, a novel SOD mimetic, on skin. RM191A is a water-soluble dimeric copper (Cu²⁺-Cu³⁺)-centred polyglycine coordination complex. It displays 10-fold higher superoxide quenching activity compared to SOD as well as significant antioxidant, anti-inflammatory and immunomodulatory activities through beneficial modulation of several significant inflammatory cytokines in vitro and in vivo.

We tested the therapeutic potential of RM191A in a topical gel using a human skin explant model and observed that it significantly inhibits UV-induced DNA damage in the epidermis and dermis, including cyclobutane pyrimidine dimers (CPD), 8-oxo-guanine (8-oxoG) and 8-nitroguanine (8NGO). RM191A topical gel is found to be non-toxic, non-teratogenic and readily distributed in the body of mice. Moreover, it significantly accelerates excisional wound healing, reduces 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation and attenuates age-associated oxidative stress in skin, demonstrating both skin regenerative and geroprotective properties of RM191A.

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RM191A is a Cu³⁺ containing coordination complex with 10-fold higher superoxide quenching activity compared to superoxide dismutase.

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RM191A exhibits potent antioxidant, anti-inflammatory and immunomodulatory properties in vitro and in vivo.

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RM191A protects human skin explants against UV-induced oxidative stress and DNA damage.

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RM191A is non-toxic, non-teratogenic and readily bioavailable in mice.

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RM191A promotes wound healing, and attenuates TPA-induced inflammation as well as age-associated oxidative stress in mouse skin.

The combination of orlistat, lonidamine and 6-diazo-5-oxo-L-norleucine induces a quiescent energetic phenotype and limits substrate flexibility in colon cancer cells

Cancer upregulates glycolysis, glutaminolysis and lipogenesis, and induces a catabolic state in patients. The concurrent inhibition of both tumor anabolism and host catabolism, and the energetic consequences of such an approach, have not previously been fully investigated. In the present study, CT26.WT murine colon cancer cells were treated with the combination of anti-anabolic drugs orlistat, lonidamine and 6-diazo-5-oxo-L-norleucine (DON; OLD scheme), which are inhibitors of the de novo synthesis of fatty acids, glycolysis and glutaminolysis, respectively. In addition, the effects of OLD scheme sumplemented with the combination of anti-catabolic compounds, namely growth hormone, insulin and indomethacin (GII scheme), were also evaluated. The effects of the compounds used in combination on CT26.WT cell viability, clonogenicity and energetic metabolism were assessed in vitro. The results demonstrated that the anti-anabolic approach reduced cell viability, clonogenicity and cell cycle progression, and increased apoptosis. These effects were associated with decreased oxidative phosphorylation, glycolysis and fuel flexibility. Furthermore, the anti-catabolic scheme, alone or supplemented with anti-anabolic compounds, did not favor tumor growth. These findings indicated that the simultaneous pharmacological inhibition of tumor anabolism and host catabolism exhibits antitumor effects that should be further evaluated.

Seeded droplet microfluidic system for small molecule crystallization

A microfluidic approach to seeded crystallization has been demonstrated using abacavir hemisulfate, a nucleoside analog reverse transcriptase inhibitor, in droplet reactors to control polymorphism and produce particles with a low particle size distribution. Two techniques are introduced: (1) the first technique involves an emulsion system consisting of a dispersed phase solvent and a continuous phase, which holds slight solubility of the dispersed phase solvent. The dispersed phase contains both a dissolved active pharmaceutical ingredient (API) and seeds of the desired polymorph. While the continuous phase enables solvent extraction, the negligible solubility of the API allows for growth of seeds inside droplets via extraction and subsequent API saturation. This technique demonstrates the ability to crystallize the API in spherical agglomerates via slow extraction of droplets. (2) The second technique utilizes a combined dispersed phase by joining in-flow a seed suspension stream with a supersaturated active pharmaceutical ingredient (API) stream. The combined dispersed phase is emulsified in a continuous phase for which the dispersed phase solvent and the API are both insoluble - droplets are incubated at temperatures below their saturation limit to induce crystal growth. Decreasing the concentration of seeds in its input stream resulted in a decreased number of crystals per droplet, increase in crystal size, and decrease in PSD. Temperature cycling was utilized as a proof of concept to demonstrate the ability to reduce the number of seeds per droplet where the optimal goal is to obtain a single seed per droplet for all droplets. Utilizing this approach in conjunction with the ability to produce monodispersed droplet reactors allows for enhanced control of particle size distribution (PSD) by precisely controlling the available mass for each individual seed crystal. The development of this technique as a proof-of-concept for crystallization can be expanded to manufacturing scales in a continuous manner using parallelized droplet generators and flow reactors to precisely control the temperature and crystal growth kinetics of individual droplets.

Sorption of radiolabelled glyphosate on biochar aged in contrasting soils

Glyphosate mobility from terrestrial to aquatic environments has raised concerns about it. Utilizing soil's inherent properties along with sorption properties of aged biochar, we hypothesized that selective application of biochar would be more effective in economic terms for glyphosate sorption on contrasting soils. To test this hypothesis, batch experiments and liquid scintillation counting for 14 C labeled glyphosate were used. The sorption behavior of glyphosate was examined in four contrasting Australian soil types (Oxisol, Vertisol, Entisol, and Inceptisol) amended with aged biochar to determine glyphosate concentrations by measuring 14 C activity using liquid scintillation counting. Freundlich parameters were calculated for soil-soil/biochar combinations. The pattern of glyphosate sorption was Oxisol > Vertisol > Entisol > Inceptisol. Oxisol adsorbed approximately five times more glyphosate compared with Inceptisol. Oxisol soil system adsorbed maximum amount of glyphosate principally due to the presence of iron-aluminum oxides exhibiting variable charges which got increased due to the presence of aged biochar. Considering all the soil/soil-biochar systems, Inceptisol soil system showed the least adsorption of glyphosate. A significant contribution of char was observed only in the Entisol soil system and the finding is valuable as char can be applied in Entisol soil systems to control glyphosate mobility.

Abstract 113: Thoracic Aortic Aneurysms Associated With Bicuspid Aortic Valve Have Altered MicroRNA Expression

Bicuspid aortic valve (BAV) is the most common congenital heart malformation, affecting 1-2% of the population. BAV is caused by fusion of two of the three aortic valve leaflets in the heart during foetal development. Progressive dilatation of the thoracic aorta, resulting in aneurysm (TAA), develops in approximately 50% of individuals with BAV, and can be fatal. The cause of BAV-TAA is undetermined, however, current understanding suggests that it is a complex interplay between genetic susceptibility and the abnormal haemodynamic stress generated by the malformed valve. Changes in the expression of post-transcriptional genetic modifiers, such as microRNA (miRNA), can alter protein expression and disrupt normal tissue function, contributing to disease. miRNA are also viable therapeutic targets with demonstrated success in disease treatment. We hypothesised that there is altered expression of miRNA in BAV-TAA tissue that contributes to TAA development. Total RNA was isolated from aortic tissue of 11 patients with BAV-TAA (Age 54 ± 12 years; M:F 10:1), and 6 normal controls with no aortic disease (Age 35 ± 18 years; M:F 4:2). RNA was reverse transcribed with primers for 818 different miRNA and qPCR was performed using Taqman® OpenArray® Human miRNA Panels. A significant difference in miRNA expression was defined as a >±2 fold change (p<0.05) compared to control. In BAV-TAA tissue, miR-214, miR-497, miR-22, miR-151-3p and miR-24 were significantly decreased. These miRNA have been previously implicated in the regulation of biological pathways relevant to BAV-TAA, including vascular smooth muscle cell (VSMC) injury and apoptosis, oxidative and shear stress, vascular relaxation, VSMC phenotype and TGF-beta signalling. Therefore, these miRNA may contribute to BAV-TAA pathogenesis, either as part of a compromised genetic background, or in relation to haemodynamic stress arising from BAV. This study has identified a novel expression profile of miRNA in BAV-TAA, and provides promising candidates for further exploration and treatment.

An endophenotype approach to the genetics of alcohol dependence: a genome wide association study of fast beta EEG in families of African ancestry

Fast beta (20-28 Hz) electroencephalogram (EEG) oscillatory activity may be a useful endophenotype for studying the genetics of disorders characterized by neural hyperexcitability, including substance use disorders (SUDs). However, the genetic underpinnings of fast beta EEG have not previously been studied in a population of African-American ancestry (AA). In a sample of 2382 AA individuals from 482 families drawn from the Collaborative Study on the Genetics of Alcoholism (COGA), we performed a genome-wide association study (GWAS) on resting-state fast beta EEG power. To further characterize our genetic findings, we examined the functional and clinical/behavioral significance of GWAS variants. Ten correlated single-nucleotide polymorphisms (SNPs) (r²>0.9) located in an intergenic region on chromosome 3q26 were associated with fast beta EEG power at P<5 × 10^-8. The most significantly associated SNP, rs11720469 (β: -0.124; P<4.5 × 10^-9), is also an expression quantitative trait locus for BCHE (butyrylcholinesterase), expressed in thalamus tissue. Four of the genome-wide SNPs were also associated with Diagnostic and Statistical Manual of Mental Disorders Alcohol Dependence in COGA AA families, and two (rs13093097, rs7428372) were replicated in an independent AA sample (Gelernter et al.). Analyses in the AA adolescent/young adult (offspring from COGA families) subsample indicated association of rs11720469 with heavy episodic drinking (frequency of consuming 5+ drinks within 24 h). Converging findings presented in this study provide support for the role of genetic variants within 3q26 in neural and behavioral disinhibition. These novel genetic findings highlight the importance of including AA populations in genetics research on SUDs and the utility of the endophenotype approach in enhancing our understanding of mechanisms underlying addiction susceptibility.

Specialized Information Processing Deficits and Distinct Metabolomic Profiles Following TM-Domain Disruption of Nrg1

Although there is considerable genetic and pathologic evidence for an association between neuregulin 1 (NRG1) dysregulation and schizophrenia, the underlying molecular and cellular mechanisms remain unclear. Mutant mice containing disruption of the transmembrane (TM) domain of the NRG1 gene constitute a heuristic model for dysregulation of NRG1-ErbB4 signaling in schizophrenia. The present study focused on hitherto uncharacterized information processing phenotypes in this mutant line. Using a mass spectrometry-based metabolomics approach, we also quantified levels of unique metabolites in brain. Across 2 different sites and protocols, Nrg1 mutants demonstrated deficits in prepulse inhibition, a measure of sensorimotor gating, that is, disrupted in schizophrenia; these deficits were partially reversed by acute treatment with second, but not first-, generation antipsychotic drugs. However, Nrg1 mutants did not show a specific deficit in latent inhibition, a measure of selective attention that is also disrupted in schizophrenia. In contrast, in a "what-where-when" object recognition memory task, Nrg1 mutants displayed sex-specific (males only) disruption of "what-when" performance, indicative of impaired temporal aspects of episodic memory. Differential metabolomic profiling revealed that these behavioral phenotypes were accompanied, most prominently, by alterations in lipid metabolism pathways. This study is the first to associate these novel physiological mechanisms, previously independently identified as being abnormal in schizophrenia, with disruption of NRG1 function. These data suggest novel mechanisms by which compromised neuregulin function from birth might lead to schizophrenia-relevant behavioral changes in adulthood.

[Intratympanic steroid intervention as initial therapy for sudden sensorineural hearing loss: a systematic review of reviews]

Objective:The aim of this overview is to evaluate the relevant systematic reviews and Meta-analysis that focus on intratympanic steroid intervention as initial therapy for sudden sensorineural hearing loss.Method:The literature search was based on the published systematic reviews and Meta analysis. According to the include and exclude critera, the important data was extracted. Quality assessment was rigorously performed using the 11-item Assessment of Multiple Systematic Reviews (AMSTAR) and main outcome indicators of literature evidence quality were evaluated by Grading of Recommendations, Assessment, Development and Evaluation (GRADE).Result:Sixteen related systemic reviews and Meta-analysis (6 Chinese literatures and 10 English literatures) published during 2009-2016 were included; AMSTAR score was 4 to 9 points,14 studies was medium quality and 2 was high quality. However, the clinical evidence was controversial and there is no consensus regarding the efficacy of intratympanic steroid therapy for sudden sensorineural hearing loss.Conclusion:As an initial treatment, there is no sufficient high quality evidence to recommend the ITS therapy. There is a need for further systematic reviews that adhere to strict scientific methods.

rs9939609 FTO genotype associations with FTO methylation level influences body mass and telomere length in an Australian rural population

BACKGROUND

The fat mass- and obesity-associated (FTO) gene influences energy homeostasis in humans. Although the obesity-related variant, rs9939609 has been replicated across a number of cohort studies, there remains significant variance and a low to modest association. Telomere length is another commonly reported obesity risk factor. We hypothesize understanding the associations between FTO rs9939609 with FTO methylation and telomere length will provide a more accurate assessment of obesity risk.

METHODS

Overall, 942 participants free of diabetes or pre-diabetes were included in the retrospective study. Leukocyte genomic DNA was analyzed for rs9939609 genotyping, FTO gene methylation and leukocyte telomere length (LTL) measurement.

RESULTS

In general linear models, rs9939609 AA genotypes were associated with increased fat percentage (3.15%, P=0.001), fat mass (4.16 kg, P=0.001), body mass index (BMI) (1.38, P=0.006) and waist circumference (3.35 cm, P=0.006), but not with FTO methylation or LTL in this overall population. However, when participants were stratified into higher and lower FTO methylation groups, the AA genotype possesses a 2.04-fold increased obesity risk in comparison to TT genotype (95%CI, 1.07-3.89, P=0.031) in participants with a higher FTO methylation level, but this association was absent in the lower FTO methylation sub-group. Moreover, AT and AA genotype carriers were associated with shorter LTL compared to TT carriers (P=0.020 and P=0.111, respectively) in the higher FTO methylation level group. However, this association was absent in the lower methylation group. Furthermore, FTO gene methylation level was significantly associated with LTL in the 942 samples (P=0.017).

CONCLUSIONS

FTO rs9939609 is associated with obesity risk and LTL in this study, where this association is only observed at higher, but not lower, FTO methylation levels of participants. Our data suggest association of multiple factors, including FTO methylation level, may be involved in one of several mechanisms underlying the commonly reported obesity risk of this FTO polymorphism.

Epistatic and Independent Effects on Schizophrenia-Related Phenotypes Following Co-disruption of the Risk Factors Neuregulin-1 × DISC1

Few studies have addressed likely gene × gene (ie, epistatic) interactions in mediating risk for schizophrenia. Using a preclinical genetic approach, we investigated whether simultaneous disruption of the risk factors Neuregulin-1 (NRG1) and Disrupted-in-schizophrenia 1 (DISC1) would produce a disease-relevant phenotypic profile different from that observed following disruption to either gene alone. NRG1 heterozygotes exhibited hyperactivity and disruption to prepulse inhibition, both reversed by antipsychotic treatment, and accompanied by reduced striatal dopamine D2 receptor protein expression, impaired social cognition, and altered glutamatergic synaptic protein expression in selected brain areas. Single gene DISC1 mutants demonstrated a disruption in social cognition and nest-building, altered brain 5-hydroxytryptamine levels and hippocampal ErbB4 expression, and decreased cortical expression of the schizophrenia-associated microRNA miR-29b. Co-disruption of DISC1 and NRG1, indicative of epistasis, evoked an impairment in sociability and enhanced self-grooming, accompanied by changes in hypothalamic oxytocin/vasopressin gene expression. The findings indicate specific behavioral correlates and underlying cellular pathways downstream of main effects of DNA variation in the schizophrenia-associated genes NRG1 and DISC1.

Measuring the Impact of Hepatitis A Virus in Chinese Cities: A Life Table Approach

The infection of hepatitis A virus is an important public health problem in China. In 1990, a survey on seroprevalence of anti-hepatitis A was conducted in eight large cities of population size between one to four million. The results were used to analyze the impact of hepatitis A. In our study, we used life table techniques to determine the impact that the hepatitis A virus (HAV) has on these eight cities by computing the expected years of life with anti-hepatitis A virus. We compared the results from our approach with those from a previous method. The expected years of life with anti-hepatitis A virus were 53.82, 54.65, 44.26, 53.89, 46.18, 55.77, 55.31 and 49.89 for the eight cities (Xi'an, Huhehaote, Chongqing, Nanjing, Jinan, Ha'erbin, Fuzhou and Nanchang), respectively. The hepatitis A virus had the greatest impact in Ha'erbin in northeastern China; whereas, the impact was lowest in Chongqing in southwestern China. However, based on the previous indicator, Chongqing was ranked the highest among these cities. Through our comparative study of the methods, our approach provides a better measure on the burden of the disease than the previous method. It also identifies subgroups of the population where the disease has its greatest impact on the population. Asia Pac J Public Health 2003; 15(2): 94-98.

Slow and steady cell shrinkage reduces osmotic stress in bovine and murine oocyte and zygote vitrification

STUDY QUESTION

Does the use of a new cryoprotectant agent (CPA) exchange protocol designed to minimize osmotic stress improve oocyte or zygote vitrification by reducing sublethal cryodamage?

SUMMARY ANSWER

The use of a new CPA exchange protocol made possible by automated microfluidics improved oocyte and zygote vitrification with superior morphology as indicated by a smoother cell surface, higher sphericity, higher cytoplasmic lipid retention, less cytoplasmic leakage and higher developmental competence compared with conventional methods.

WHAT IS KNOWN ALREADY

The use of more 'steps' of CPA exposure during the vitrification protocol increases cryosurvival and development in the bovine model. However, such an attempt to eliminate osmotic stress is limited by the practicality of performing numerous precise pipetting steps in a short amount of time.

STUDY DESIGN, SIZE, DURATION

Murine meiotically competent germinal vesicle intact oocytes and zygotes were harvested from the antral follicles in ovaries and ampulla, respectively. Bovine ovaries were obtained from a local abattoir at random stages of the estrous cycle. A total of 110 murine oocytes, 802 murine zygotes and 52 bovine oocytes were used in this study.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Microfluidic devices were fabricated using conventional photo- and soft-lithography. CPAs used were 7.5% ethylene glycol (EG) and 7.5% dimethyl sulfoxide (DMSO) for equilibration solution and 15% EG, 15% DMSO and 0.5 M sucrose for vitrification solution. End-point analyses include mathematical modeling using Kedem-Katchalsky equations, morphometrics assessed by conventional and confocal microscopy, cytoplasmic lipid quantification by nile red staining, cytoplasmic leakage quantification by fluorescent dextran intercalation and developmental competence analysis by 96 h embryo culture and blastomere quantification.

MAIN RESULTS AND THE ROLE OF CHANCE

The automated microfluidics protocol decreased the shrinkage rate of the oocyte and zygote by 13.8 times over its manual pipetting alternative. Oocytes and zygotes with a lower shrinkage rate during CPA exposure experienced less osmotic stress resulting in better morphology, higher cell quality and improved developmental competence. This microfluidic procedure resulted in murine zygotes with a significantly smoother cell surface (P < 0.001), more spherical cellular morphology (P < 0.001), increased cytoplasmic lipid retention in vitrified and warmed bovine oocytes (P < 0.01), decreased membrane perforations and cytoplasmic leakage in CPA-exposed murine zygotes (P < 0.05) and improved developmental competence of vitrified and warmed murine zygotes (P < 0.05) than CPA exposure using the current clinically used manual pipetting method.

LIMITATIONS, REASONS FOR CAUTION

It is necessary to design the microfluidic device to be more user-friendly for widespread use.

WIDER IMPLICATIONS OF THE FINDINGS

The theory and approach of eliminating osmotic stress by decreasing shrinkage rate is complementary to the prevalent osmotic stress theory in cryobiology which focuses on a minimum cell volume at which the cells shrink. The auto-microfluidic protocol described here has immediate applications for improving animal and human oocyte, zygote and embryo cryopreservation. On a fundamental level, the clear demonstration that at the same minimum cell volume, cell shrinkage rate affects sublethal damage should be broadly useful for cryobiology.

STUDY FUNDING/COMPETING INTERESTS

This project was funded by the National Institutes of Health and the University of Michigan Reproductive Sciences Program. The authors declare no conflicts of interest.

Genetic variant predicts bevacizumab-induced hypertension in ECOG-5103 and ECOG-2100

BACKGROUND

Bevacizumab has broad anti-tumour activity, but substantial risk of hypertension. No reliable markers are available for predicting bevacizumab-induced hypertension.

METHODS

A genome-wide association study (GWAS) was performed in the phase III bevacizumab-based adjuvant breast cancer trial, ECOG-5103, to evaluate for an association between genotypes and hypertension. GWAS was conducted in those who had experienced systolic blood pressure (SBP) >160 mm Hg during therapy using binary analysis and a cumulative dose model for the total exposure of bevacizumab. Common toxicity criteria (CTC) grade 3-5 hypertension was also assessed. Candidate SNP validation was performed in the randomised phase III trial, ECOG-2100.

RESULTS

When using the phenotype of SBP>160 mm Hg, the most significant association in SV2C (rs6453204) approached and met genome-wide significance in the binary model (P=6.0 × 10(-8); OR=3.3) and in the cumulative dose model (P=4.7 × 10(-8); HR=2.2), respectively. Similar associations with rs6453204 were seen for CTC grade 3-5 hypertension but did not meet genome-wide significance. Validation study from ECOG-2100 demonstrated a statistically significant association between this SNP and grade 3/4 hypertension using the binary model (P-value=0.037; OR=2.4).

CONCLUSIONS

A genetic variant in SV2C predicted clinically relevant bevacizumab-induced hypertension in two independent, randomised phase III trials.

Phenotypic effects of maternal immune activation and early postnatal milieu in mice mutant for the schizophrenia risk gene neuregulin-1

Risk of schizophrenia is likely to involve gene × environment (G × E) interactions. Neuregulin 1 (NRG1) is a schizophrenia risk gene, hence any interaction with environmental adversity, such as maternal infection, may provide further insights into the basis of the disease. This study examined the individual and combined effects of prenatal immune activation with polyriboinosinic-polyribocytidilic acid (Poly I:C) and disruption of the schizophrenia risk gene NRG1 on the expression of behavioral phenotypes related to schizophrenia. NRG1 heterozygous (NRG1 HET) mutant breeding pairs were time-mated. Pregnant dams received a single injection (5mg/kg i.p.) of Poly I:C or vehicle on gestation day 9 (GD9). Offspring were then cross-fostered to vehicle-treated or Poly I:C-treated dams. Expression of schizophrenia-related behavioral endophenotypes was assessed at adolescence and in adulthood. Combining NRG1 disruption and prenatal environmental insult (Poly I:C) caused developmental stage-specific deficits in social behavior, spatial working memory and prepulse inhibition (PPI). However, combining Poly I:C and cross-fostering produced a number of behavioral deficits in the open field, social behavior and PPI. This became more complex by combining NRG1 deletion with both Poly I:C exposure and cross-fostering, which had a robust effect on PPI. These findings suggest that concepts of G × E interaction in risk of schizophrenia should be elaborated to multiple interactions that involve individual genes interacting with diverse biological and psychosocial environmental factors over early life, to differentially influence particular domains of psychopathology, sometimes over specific stages of development.

Differential placental gene expression in term pregnancies affected by fetal growth restriction and macrosomia

INTRODUCTION

Extremes of fetal growth are associated with increased perinatal mortality and morbidity and a higher prevalence of cardiovascular disease, obesity and diabetes in later life. We aimed to identify changes in placental gene expression in pregnancies with evidence of growth dysfunction and candidate genes that may be used to identify abnormal patterns of growth prior to delivery.

METHODS

Growth-restricted (n = 4), macrosomic (n = 6) and normal term (n = 5) placentas were selected from a banked series (n = 200) collected immediately after caesarean section. RNA was extracted prior to microarray analysis using Affymetrix HG-U219 arrays to determine variation in gene expression. Genes of interest were confirmed using qRT-PCR.

RESULTS

338 genes in the growth-restricted and 41 genes in the macrosomic group were identified to be significantly dysregulated (>2-fold change; p < 0.05). CPXM2 and CLDN1 were upregulated and TXNDC5 and LRP2 downregulated in fetal growth restriction. In macrosomia, PHLDB2 and CLDN1 were upregulated and LEP and GCH1 were downregulated.

DISCUSSION

Dysfunctional growth is associated with differential placental gene expression and affects genes with a whole spectrum of developmental and cellular functions. Better elucidation of these pathways may allow the development of biomarkers to identify growth abnormalities and effective prenatal intervention.

Effects of newly developed chemotherapy regimens, comorbidities, chemotherapy-related toxicities on the changing patterns of the leading causes of death in elderly patients with colorectal cancer

BACKGROUND

Abundant evidences have shown that newly developed chemotherapy regimens improved 5-year survival rate of colorectal cancer (CRC) patients over the past two decades. However, their impact on risk of death from leading causes among elderly patients is still poorly understood.

PATIENTS AND METHODS

A retrospective cohort study of 69 718 elderly CRC patients with their first primary tumors in 1992-2009, identified from the 12 areas of Surveillance, Epidemiology, and End Results-Medicare linked database with their Medicare claims up to 2010. Multivariate Cox regression models were used to assess the effect of newly developed chemotherapy regimens, comorbidities, and chemotherapy related toxicities on cause-specific death and their temporal patterns among elderly CRC patients.

RESULTS

The leading causes of death among CRC patients were CRC, circulation disorders, and secondary cancers, which accounted for 51.4%, 25%, and 4.6% of all-cause death, respectively. Patients diagnosed in more recent diagnostic time periods were significantly less likely to die of CRC [period 2: 5-year hazard ratio = 0.94, 95% confidence interval (CI) 0.90-0.97; period 3: 0.86, 0.83-0.90], circulation disorders (period 2: 0.94, 0.88-1.00; period 3: 0.80, 0.75-0.87), and more likely to die of secondary cancer (period 3: 1.42, 1.20-1.68) compared with those diagnosed in period 1. Charlson comorbidities index and the selected pre-existing comorbidities were significantly associated with increased 5-year risk of death from all three leading causes. Both hematological and gastric toxicity were associated with reduced risk of death from CRC and circulation disorders. The association between diagnostic time period and risk reduction in death from CRC depended on chemotherapy treatment (P < 0.0001). Subgroup analyses showed that the chemotherapy-dependent significant risk reduction was seen in patients with stage II-III CRC, patients without comorbidities, and patients without toxicities (P < 0.0001 for all).

CONCLUSION

The newly developed chemotherapy regimens were associated with the decreased risk of mortality from CRC.

Expression and characterization of a soluble VEGF receptor 2 protein

Objective

To clone and express a truncated, soluble vascular endothelial growth factor receptor 2 (sVEGFR2) possessing the combined-functional domains 1–3 and 5 in eukaryotic cells and to test the inhibitory effects of full length VEGFR2 in vivo.

Results

pCMV6-trunctated-rVegfr2 (6100 bp) was successfully cloned. The transfection experiments showed that either pCMV6-truncated-rat-Vegfr2 (pCMV6-truncated-rVegfr2) or pCMV6-rVegfr2 inhibited the expression of intracellular green fluorescent protein, which is usually used as an exogenous transfected reporter gene to determine the transfected efficiency. An analysis of the transfected cells revealed that the amount of full-length VEGFR2 protein in the pCMV6-truncated-rVegfr2 transfected cells was 20% lower than that in the negative control (non-transfected HEK 293 cells). The differences in test results between the transfected and negative control groups were greatest from 24–30 h after transfection; this period was therefore chosen as optimal for collecting culture supernatants. This analysis was highly sensitive for detecting the amount of sVEGFR2 protein expressed and secreted by the cells, and the sVEGFR2 protein content was found to increase by approximately 26% in the transfected cells compared to that in the negative control cells (68.2% ± 1.7% vs. 41.9% ± 2.9%, P = 0.000) and by 18% compared to the negative control cells (68.2% ± 1.7% vs. 50.0% ± 0.5%, P = 0.003). Propidium iodide and Hoechst staining indicated no significant change in the number of HEK293 cells undergoing apoptosis 6 days after pCMV6-trucated-Vegfr2 transfection, compared to the negative control. Soluble VEGFR2 produced by pCMV6-truncated-rVegfr2 inhibited full-length VEGFR2 protein expression in the cell membrane.

Conclusions

This study employed a eukaryotic system to express sVEGFR2. The use of transient transfection technology greatly improved transfect efficiency. Recombinant sVEGFR2 inhibited the effect of endogenous full-length VEGFR2 but was not cytotoxic.

Enrichment of ovarian cancer stem-like cells is associated with epithelial to mesenchymal transition through an miRNA-activated AKT pathway

OBJECTIVES

Evidence has indicated that ovarian epithelial cancer-type cells under serum-free culture conditions can form spheroid cells and exhibit characteristics expected of cancer stem-like cells (CSCs). However, the mechanism by which differentiated ovarian cancer cells acquire stem-cell properties during CSC enrichment has needed to be elucidated. Recent studies have demonstrated that induction of epithelial to mesenchymal transition (EMT) can generate CSCs and be associated with tumour aggressiveness and metastasis.

MATERIALS AND METHODS

Ovarian epithelial cancer cell lines, SKOV3 and HO8920, were cultured for spheroid cells and adherent cells. CSC enrichment was investigated using MTT assay, flow cytometery and qRT-PCR and expression level of PI3K/AKT pathway components was analysed by western blotting.

RESULTS

Compared to adherent cells, the spheroid cells expressed mesenchymal markers highly and exhibited significantly more motility; we also observed increases in phosphate AKT1 levels in the spheroid cells. Moreover, transfection of miR-20a or miR-200c led to corresponding reduction in endogenous PTEN protein, while AKT1 and phosphate AKT1 levels were upregulated in miRNAs-transfected cells. Finally, PI3K/AKT pathway inhibitor LY294002 reduced expressions of mesenchymal markers and stem-cell gene activity in spheroid cells, enhancing sensitivity of spheroid cells to paclitaxel treatment.

CONCLUSIONS

Our findings demonstrate that EMT contributed to enrichment of ovarian CSCs in vitro, making EMT targeting in epithelial ovarian cancer a novel therapeutic option.

KLF5 strengthens drug resistance of ovarian cancer stem-like cells by regulating survivin expression

OBJECTIVES

Ovarian cancer stem-like cells (CSCs), which can form non-adherent sphere cells in a stem-cell selection culture system, exhibit stemness and drug resistance to chemotherapeutics, which are properties not observed in differentiated cells. Recent studies have demonstrated that Kruppel-like factor 5 (KLF5) is involved in cell proliferation and mediates cell survival and tumourigenesis. Here, we investigated the role of KLF5 and its downstream target survivin, in strengthening drug resistance of ovarian CSCs.

MATERIALS AND METHODS

Ovarian cancer cell line SKOV3 was cultured under serum-free conditions and differentiating conditions to promote formation of sphere cells and differentiated cells, respectively. siRNA-KLF5 was used to knock down KLF5, and survivin expression vector was used to overexpress survivin. Cells were further analysed by qPCR, immunofluorescence staining and western blotting. Chromatin immunoprecipitation (ChIP) assay and electrophoretic mobility shift assay (EMSA) were performed to investigate the relationship between KLF5 and survivin expression. Drug resistance was examined by MTT and apoptosis assays.

RESULTS

KLF5 was highly expressed in the ovarian cancer cell line SKOV3 sphere cells, accompanied by elevated survivin expression. Silencing KLF5 by small interfering RNA in sphere cells down-regulated survivin expression, which also sensitized the sphere cells to apoptosis induced by chemotherapeutic drugs (cisplatin or paclitaxel). Furthermore, ChIP assay, survivin overexpression and EMSA results indicated that KLF5 controlled survivin expression by directly binding the surivin promoter in the cells.

CONCLUSIONS

The KLF5-mediated signalling pathway is a potential target for elimination of ovarian CSCs.

Thinking big by thinking small: application of microfluidic technology to improve ART

In Vitro Fertilization (IVF) laboratories often carry a penchant to resist change while in the pursuit of maintaining consistency in laboratory conditions. However, implementation of new technology is often critical to expand scientific discoveries and to improve upon prior successes to advance the field. Microfluidic platforms represent a technology that has the potential to revolutionize the fundamental processes of IVF. While the focus of microfluidic application in IVF has centered on embryo culture, the innovative platforms carry tremendous potential to improve other procedural steps and represents a possible paradigm shift in how we handle gametes and embryos. The following review will highlight application of various microfluidic platforms in IVF for use in maturation, manipulation, culture, cryopreservation and non-invasive quality assessment; pointing out new insights gained into functions of sperm, oocytes and embryos. Platform design and function will also be discussed, focusing on limitations, advancements and future refinements that can further aid in their clinical implementation.

Imaging of highly malignant osteosarcoma with iodine-123-vascular endothelial growth factor

OBJECTIVE

Vascular endothelial growth factor (VEGF) is an important angiogenic factor, and its receptors have been shown to be overexpressed in various human carcinomas. In this study, we investigated the role of scanning with iodine-123 ((123)I)-labelled VEGF(165) in patients with highly malignant osteosarcoma.

METHODS

Two patients (a 15-year-old female and a 14-year-old male) with osteosarcoma were injected with 140 MBq [<130 pmol (<5 µg) VEGF(165) per patient] of (123)I-VEGF(165). Dynamic acquisition was initiated immediately after administration and carried out until 30 min after injection. Whole-body images were done in anterior and posterior views at various time points. All patients underwent single-photon emission tomography imaging.

RESULTS

(123)I-VEGF(165) scans were positive in these patients. Sequential images clearly showed increased (123)I-VEGF(165) activity in osteosarcoma lesions. The tumour lesions were still visualized in whole-body images and single-photon emission tomography examinations 2 h after injection. Intravenous injection of (123)I-VEGF(165) did not cause any side effects.

CONCLUSION

Our results suggest that (123)I-VEGF(165) receptor scintigraphy may be useful for the visualization of highly malignant osteosarcoma and/or metastasis and the angiogenic activity of the tumour.

miR-21, miR-17 and miR-19a induced by phosphatase of regenerating liver-3 promote the proliferation and metastasis of colon cancer

Background:

Phosphatase of regenerating liver-3 (PRL-3) is an oncogene known to promote tumour metastasis, especially in colorectal cancer (CRC). Here, we demonstrate that the miR-21, miR-17 and miR-19a expressions induced by PRL-3 are involved in the proliferation and metastasis of colon cancer.

Methods:

Microarray analysis and quantitative reverse-transcription polymerase chain reactions (qRT–PCR) were used to investigate the changes in miRNA expression due to the overexpression of PRL-3. Transwell chamber invasion assays, CCK-8 proliferation assays and RNA interference assays were used to explore the effects of PRL-3 on miR-21, miR-17 and miR-19a expression in colon cancer cells. Immunohistochemistry and qRT–PCR were performed in colon cancer tissues to evaluate the expression of PRL-3, signal transducer and activator of transcription 3 (STAT3), miR-21, miR-17 and miR-19a.

Results:

Our study demonstrated that the overexpression of PRL-3 in colon cancer cells induced the expression of miR-21, miR-17 and miR-19a by activating STAT3. Subsequently, these microRNAs contributed to the increased proliferation and invasiveness of the colon cancer cells. Positive correlations between PRL-3 and these microRNAs were also observed in matched primary colon cancer tissues and metastatic lesions.

Conclusion:

miR-21, miR-17 and miR-19a induced by PRL-3 contribute to the proliferation and invasion of colon cancer.

Disease modeling by gene targeting using microRNAs

Zebrafish have proved to be a popular species for the modeling of human disease. In this context, there is a need to move beyond chemical-based mutagenesis and develop tools that target genes that are orthologous to those that are implicated in human heritable diseases. Targeting can take the form of creating mutations that are nonsense or mis-sense, or to mimic haploinsufficiency through the regulated expression of RNA effector molecules. In terms of the latter, we describe here the development and investigation of microRNA (miRNA)-based directed gene silencing methods in zebrafish. Unlike small interfering RNAs (siRNAs), miRNA-based methods offer temporal and spatial regulation of gene silencing. Proof-of-concept experiments demonstrate the efficacy of the method in zebrafish embryos, which provide the foundation for developing disease models using miRNA-based gene-targeting.