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2.
Nature ; 540(7633): 395-399, 2016 12 14.
Article in English | MEDLINE | ID: mdl-27974754

ABSTRACT

Seahorses have a specialized morphology that includes a toothless tubular mouth, a body covered with bony plates, a male brood pouch, and the absence of caudal and pelvic fins. Here we report the sequencing and de novo assembly of the genome of the tiger tail seahorse, Hippocampus comes. Comparative genomic analysis identifies higher protein and nucleotide evolutionary rates in H. comes compared with other teleost fish genomes. We identified an astacin metalloprotease gene family that has undergone expansion and is highly expressed in the male brood pouch. We also find that the H. comes genome lacks enamel matrix protein-coding proline/glutamine-rich secretory calcium-binding phosphoprotein genes, which might have led to the loss of mineralized teeth. tbx4, a regulator of hindlimb development, is also not found in H. comes genome. Knockout of tbx4 in zebrafish showed a 'pelvic fin-loss' phenotype similar to that of seahorses.


Subject(s)
Biological Evolution , Fish Proteins/genetics , Genome/genetics , Smegmamorpha/anatomy & histology , Smegmamorpha/genetics , Animal Fins/anatomy & histology , Animal Fins/metabolism , Animals , Conserved Sequence/genetics , Fish Proteins/deficiency , Gene Deletion , Genomics , Hindlimb/anatomy & histology , Hindlimb/metabolism , Male , Molecular Sequence Annotation , Multigene Family/genetics , Mutation Rate , Phylogeny , Reproduction/physiology , T-Box Domain Proteins/deficiency , T-Box Domain Proteins/genetics , Time Factors , Zebrafish Proteins/deficiency , Zebrafish Proteins/genetics
3.
Ophthalmology ; 127(8): 1064-1076, 2020 08.
Article in English | MEDLINE | ID: mdl-32197910

ABSTRACT

PURPOSE: To examine the normative profile and determinants of macular ganglion cell-inner plexiform layer (GCIPL) thickness based on spectral-domain OCT (SD-OCT) in a nonglaucoma, multi-ethnic Asian population. DESIGN: Population-based, cross-sectional study. PARTICIPANTS: Ethnic Chinese, Malay, and Indian adults aged ≥40 years recruited from the Singapore Epidemiology of Eye Diseases Study. METHODS: All participants underwent standardized examinations. The GCIPL thickness was measured using Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA). Participants with glaucoma or poor-quality scans were excluded. Eye-specific data were used. Associations of ocular and systemic factors with GCIPL thickness parameters were investigated using multivariable linear regression with generalized estimating equation models to account for correlation between both eyes. MAIN OUTCOME MEASURES: GCIPL thickness. RESULTS: A total of 4464 participants (7520 eyes) consisting of 1625 Chinese, 1212 Malay, and 1627 Indian adults contributed to this analysis. Average GCIPL thickness was 82.6±6.1 µm in Chinese, 81.5±6.8 µm in Malays, and 78.0±6.9 µm in Indians (P < 0.001 by analysis of variance). The 5th percentile limit of average GCIPL thickness was 72 µm in Chinese, 70 µm in Malays, and 67 µm in Indians. In multivariable analysis adjusting for age, gender, axial length, presence of cataract, OCT signal strength, disc area, hypertension, diabetes, and hyperlipidemia, eyes of Indians were observed to have 3.43 µm thinner GCIPL on average compared with Chinese (P < 0.001) and 3.36 µm thinner GCIPL compared with Malays (P < 0.001). In addition, older age (per decade; ß = -2.51), female (ß = -1.57), longer axial length (per mm; ß = -1.54), and presence of chronic kidney disease (ß = -1.49) were significantly associated with thinner average GCIPL (all P ≤ 0.008). Larger optic disc area (per mm2; ß = 0.78; P < 0.001) was associated with thicker GCIPL. These factors were consistently observed to be significant for superior and inferior hemisphere GCIPL thickness. CONCLUSIONS: GCIPL thickness profiles were significantly thinner in Indians compared with Chinese and Malays. Our findings further highlight the need of a more refined, ethnic-specific normative database for GCIPL thickness, which in turn may improve the detection and diagnosis of glaucoma in Asians.


Subject(s)
Ethnicity , Glaucoma/ethnology , Population Surveillance , Retinal Ganglion Cells/pathology , Cross-Sectional Studies , Female , Glaucoma/diagnosis , Humans , Male , Middle Aged , Nerve Fibers , Optic Disk , Singapore/epidemiology , Tomography, Optical Coherence
4.
Nature ; 505(7482): 174-9, 2014 Jan 09.
Article in English | MEDLINE | ID: mdl-24402279

ABSTRACT

The emergence of jawed vertebrates (gnathostomes) from jawless vertebrates was accompanied by major morphological and physiological innovations, such as hinged jaws, paired fins and immunoglobulin-based adaptive immunity. Gnathostomes subsequently diverged into two groups, the cartilaginous fishes and the bony vertebrates. Here we report the whole-genome analysis of a cartilaginous fish, the elephant shark (Callorhinchus milii). We find that the C. milii genome is the slowest evolving of all known vertebrates, including the 'living fossil' coelacanth, and features extensive synteny conservation with tetrapod genomes, making it a good model for comparative analyses of gnathostome genomes. Our functional studies suggest that the lack of genes encoding secreted calcium-binding phosphoproteins in cartilaginous fishes explains the absence of bone in their endoskeleton. Furthermore, the adaptive immune system of cartilaginous fishes is unusual: it lacks the canonical CD4 co-receptor and most transcription factors, cytokines and cytokine receptors related to the CD4 lineage, despite the presence of polymorphic major histocompatibility complex class II molecules. It thus presents a new model for understanding the origin of adaptive immunity.


Subject(s)
Evolution, Molecular , Genome/genetics , Sharks/genetics , Animals , Calcium/metabolism , Cell Lineage/immunology , Fish Proteins/classification , Fish Proteins/genetics , Gene Deletion , Genomics , Immunity, Cellular/genetics , Molecular Sequence Annotation , Molecular Sequence Data , Osteogenesis/genetics , Phosphoproteins/genetics , Phosphoproteins/metabolism , Phylogeny , Protein Structure, Tertiary/genetics , Sharks/immunology , T-Lymphocytes/cytology , T-Lymphocytes/immunology , Time Factors , Vertebrates/classification , Vertebrates/genetics , Zebrafish/genetics , Zebrafish/growth & development
5.
Nature ; 513(7518): 375-381, 2014 Sep 18.
Article in English | MEDLINE | ID: mdl-25186727

ABSTRACT

Cichlid fishes are famous for large, diverse and replicated adaptive radiations in the Great Lakes of East Africa. To understand the molecular mechanisms underlying cichlid phenotypic diversity, we sequenced the genomes and transcriptomes of five lineages of African cichlids: the Nile tilapia (Oreochromis niloticus), an ancestral lineage with low diversity; and four members of the East African lineage: Neolamprologus brichardi/pulcher (older radiation, Lake Tanganyika), Metriaclima zebra (recent radiation, Lake Malawi), Pundamilia nyererei (very recent radiation, Lake Victoria), and Astatotilapia burtoni (riverine species around Lake Tanganyika). We found an excess of gene duplications in the East African lineage compared to tilapia and other teleosts, an abundance of non-coding element divergence, accelerated coding sequence evolution, expression divergence associated with transposable element insertions, and regulation by novel microRNAs. In addition, we analysed sequence data from sixty individuals representing six closely related species from Lake Victoria, and show genome-wide diversifying selection on coding and regulatory variants, some of which were recruited from ancient polymorphisms. We conclude that a number of molecular mechanisms shaped East African cichlid genomes, and that amassing of standing variation during periods of relaxed purifying selection may have been important in facilitating subsequent evolutionary diversification.


Subject(s)
Cichlids/classification , Cichlids/genetics , Evolution, Molecular , Genetic Speciation , Genome/genetics , Africa, Eastern , Animals , DNA Transposable Elements/genetics , Gene Duplication/genetics , Gene Expression Regulation/genetics , Genomics , Lakes , MicroRNAs/genetics , Phylogeny , Polymorphism, Genetic/genetics
6.
Clin Exp Ophthalmol ; 48(9): 1210-1218, 2020 12.
Article in English | MEDLINE | ID: mdl-32734654

ABSTRACT

IMPORTANCE: Evidence-based guidelines are essential for glaucoma screening to work effectively. BACKGROUND: To derive a vertical cup-to-disc ratio (VCDR) cut-off for glaucoma screening in a multi-ethnic Asian population. DESIGN: The Singapore Epidemiology of Eye Diseases (SEED) study is a population-based study conducted from 2004 to 2011 in a single tertiary care research institute. PARTICIPANTS: SEED comprised of 10 033 Chinese, Malay and Indian adults aged ≥40 (response rate 75.6%). After excluding participants with a history of glaucoma medication or surgery, 9673 participants were included for analysis. METHODS: A systematic eye examination, which included applanation tonometry, visual field testing, gonioscopy and dilated fundus examination was conducted. MAIN OUTCOME MEASURE: Diagnosis of glaucoma. RESULTS: The distribution of VCDR and VCDR asymmetry were relatively homogenous in this multi-ethnic Asian population, with a 97.5th percentile value of 0.67 and 0.17, respectively. In the absence of more definite signs of glaucoma, VCDR ≥0.60 and VCDR asymmetry ≥0.20 provided the best balance between sensitivity (95.1%) and specificity (90.9%) in detecting glaucoma. For larger optic disc (≥2.0 mm), VCDR ≥0.65 with VCDR asymmetry ≥0.20 provided the best balance between sensitivity (84.8%) and specificity (93.2%). CONCLUSION AND RELEVANCE: Overall, VCDR ≥0.60 with VCDR ≥0.20 asymmetry provides a good balance between sensitivity and specificity in detecting glaucoma. For larger optic disc, VCDR ≥0.65 should be considered instead to mitigate against false-referrals due to larger physiological disc cupping. Our findings may act as a reference to populations with similar VCDR distribution.


Subject(s)
Glaucoma , Optic Disk , Adult , Diagnostic Techniques, Ophthalmological , Humans , Intraocular Pressure , Tonometry, Ocular , Visual Field Tests
7.
Bioconjug Chem ; 29(7): 2176-2180, 2018 07 18.
Article in English | MEDLINE | ID: mdl-29944344

ABSTRACT

A new glucose-responsive insulin delivery system is fabricated using biomimetic peptide coacervates derived from the Humboldt squid (Dosidicus Gigas) beak. Both insulin and glucose oxidase are coencapsulated within coacervate microdroplets. The glucose oxidase quickly responds to increasing glucose levels to generate a local acidic environment, thereby rapidly triggering the dissociation of pH-sensitive coacervates to release the insulin cargo. The rate of insulin release is dependent on the glucose level, increases under hyperglycemic conditions, and decreases under normoglycemic conditions. This glucose responsiveness mimics pancreatic ß-cell function by releasing insulin according to glucose levels.


Subject(s)
Capsules/therapeutic use , Drug Delivery Systems/methods , Insulin/administration & dosage , Peptides/therapeutic use , Animals , Beak/chemistry , Capsules/chemistry , Decapodiformes , Delayed-Action Preparations/chemistry , Delayed-Action Preparations/pharmacokinetics , Glucose/metabolism , Glucose/pharmacology , Glucose Oxidase , Humans , Hydrogen-Ion Concentration , Peptides/drug effects
9.
Eye Vis (Lond) ; 11(1): 21, 2024 Jun 03.
Article in English | MEDLINE | ID: mdl-38831465

ABSTRACT

BACKGROUND: Myopia affects 1.4 billion individuals worldwide. Notably, there is increasing evidence that choroidal thickness plays an important role in myopia and risk of developing myopia-related conditions. With the advancements in artificial intelligence (AI), choroidal thickness segmentation can now be automated, offering inherent advantages such as better repeatability, reduced grader variability, and less reliance for manpower. Hence, we aimed to evaluate the agreement between AI-automated and manual segmented measurements of subfoveal choroidal thickness (SFCT) using two swept-source optical coherence tomography (OCT) systems. METHODS: Subjects aged ≥ 16 years, with myopia of ≥ 0.50 diopters in both eyes, were recruited from the Prospective Myopia Cohort Study in Singapore (PROMYSE). OCT scans were acquired using Triton DRI-OCT and PLEX Elite 9000. OCT images were segmented both automatically with an established SA-Net architecture and manually using a standard technique with adjudication by two independent graders. SFCT was subsequently determined based on the segmentation. The Bland-Altman plot and intraclass correlation coefficient (ICC) were used to evaluate the agreement. RESULTS: A total of 229 subjects (456 eyes) with mean [± standard deviation (SD)] age of 34.1 (10.4) years were included. The overall SFCT (mean ± SD) based on manual segmentation was 216.9 ± 82.7 µm with Triton DRI-OCT and 239.3 ± 84.3 µm with PLEX Elite 9000. ICC values demonstrated excellent agreement between AI-automated and manual segmented SFCT measurements (PLEX Elite 9000: ICC = 0.937, 95% CI: 0.922 to 0.949, P < 0.001; Triton DRI-OCT: ICC = 0.887, 95% CI: 0.608 to 0.950, P < 0.001). For PLEX Elite 9000, manual segmented measurements were generally thicker when compared to AI-automated segmented measurements, with a fixed bias of 6.3 µm (95% CI: 3.8 to 8.9, P < 0.001) and proportional bias of 0.120 (P < 0.001). On the other hand, manual segmented measurements were comparatively thinner than AI-automated segmented measurements for Triton DRI-OCT, with a fixed bias of - 26.7 µm (95% CI: - 29.7 to - 23.7, P < 0.001) and proportional bias of - 0.090 (P < 0.001). CONCLUSION: We observed an excellent agreement in choroidal segmentation measurements when comparing manual with AI-automated techniques, using images from two SS-OCT systems. Given its edge over manual segmentation, automated segmentation may potentially emerge as the primary method of choroidal thickness measurement in the future.

10.
Br J Ophthalmol ; 2023 Dec 11.
Article in English | MEDLINE | ID: mdl-38164563

ABSTRACT

BACKGROUND: Large language models (LLMs) are fast emerging as potent tools in healthcare, including ophthalmology. This systematic review offers a twofold contribution: it summarises current trends in ophthalmology-related LLM research and projects future directions for this burgeoning field. METHODS: We systematically searched across various databases (PubMed, Europe PMC, Scopus and Web of Science) for articles related to LLM use in ophthalmology, published between 1 January 2022 and 31 July 2023. Selected articles were summarised, and categorised by type (editorial, commentary, original research, etc) and their research focus (eg, evaluating ChatGPT's performance in ophthalmology examinations or clinical tasks). FINDINGS: We identified 32 articles meeting our criteria, published between January and July 2023, with a peak in June (n=12). Most were original research evaluating LLMs' proficiency in clinically related tasks (n=9). Studies demonstrated that ChatGPT-4.0 outperformed its predecessor, ChatGPT-3.5, in ophthalmology exams. Furthermore, ChatGPT excelled in constructing discharge notes (n=2), evaluating diagnoses (n=2) and answering general medical queries (n=6). However, it struggled with generating scientific articles or abstracts (n=3) and answering specific subdomain questions, especially those regarding specific treatment options (n=2). ChatGPT's performance relative to other LLMs (Google's Bard, Microsoft's Bing) varied by study design. Ethical concerns such as data hallucination (n=27), authorship (n=5) and data privacy (n=2) were frequently cited. INTERPRETATION: While LLMs hold transformative potential for healthcare and ophthalmology, concerns over accountability, accuracy and data security remain. Future research should focus on application programming interface integration, comparative assessments of popular LLMs, their ability to interpret image-based data and the establishment of standardised evaluation frameworks.

11.
Front Med (Lausanne) ; 10: 1235309, 2023.
Article in English | MEDLINE | ID: mdl-37928469

ABSTRACT

Introduction: Our study aimed to examine the relationship between cardiovascular diseases (CVD) with peripapillary retinal fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) thickness profiles in a large multi-ethnic Asian population study. Methods: 6,024 Asian subjects were analyzed in this study. All participants underwent standardized examinations, including spectral domain OCT imaging (Cirrus HD-OCT; Carl Zeiss Meditec). In total, 9,188 eyes were included for peripapillary RNFL analysis (2,417 Malays; 3,240 Indians; 3,531 Chinese), and 9,270 eyes (2,449 Malays, 3,271 Indians, 3,550 Chinese) for GCIPL analysis. History of CVD was defined as a self-reported clinical history of stroke, myocardial infarction, or angina. Multivariable linear regression models with generalized estimating equations were performed, adjusting for age, gender, ethnicity, diabetes, hypertension, hyperlipidaemia, chronic kidney disease, body mass index, current smoking status, and intraocular pressure. Results: We observed a significant association between CVD history and thinner average RNFL (ß = -1.63; 95% CI, -2.70 to -0.56; p = 0.003). This association was consistent for superior (ß = -1.79, 95% CI, -3.48 to -0.10; p = 0.038) and inferior RNFL quadrant (ß = -2.14, 95% CI, -3.96 to -0.32; p = 0.021). Of the CVD types, myocardial infarction particularly showed significant association with average (ß = -1.75, 95% CI, -3.08 to -0.42; p = 0.010), superior (ß = -2.22, 95% CI, -4.36 to -0.09; p = 0.041) and inferior (ß = -2.42, 95% CI, -4.64 to -0.20; p = 0.033) RNFL thinning. Among ethnic groups, the association between CVD and average RNFL was particularly prominent in Indian eyes (ß = -1.92, 95% CI, -3.52 to -0.33; p = 0.018). CVD was not significantly associated with average GCIPL thickness, albeit a consistent negative direction of association was observed (ß = -0.22, 95% CI, -1.15 to 0.71; p = 0.641). Discussion: In this large multi-ethnic Asian population study, we observed significant association between CVD history and RNFL thinning. This finding further validates the impact of impaired systemic circulation on RNFL thickness.

12.
iScience ; 26(11): 108163, 2023 Nov 17.
Article in English | MEDLINE | ID: mdl-37915603

ABSTRACT

In light of growing interest in using emerging large language models (LLMs) for self-diagnosis, we systematically assessed the performance of ChatGPT-3.5, ChatGPT-4.0, and Google Bard in delivering proficient responses to 37 common inquiries regarding ocular symptoms. Responses were masked, randomly shuffled, and then graded by three consultant-level ophthalmologists for accuracy (poor, borderline, good) and comprehensiveness. Additionally, we evaluated the self-awareness capabilities (ability to self-check and self-correct) of the LLM-Chatbots. 89.2% of ChatGPT-4.0 responses were 'good'-rated, outperforming ChatGPT-3.5 (59.5%) and Google Bard (40.5%) significantly (all p < 0.001). All three LLM-Chatbots showed optimal mean comprehensiveness scores as well (ranging from 4.6 to 4.7 out of 5). However, they exhibited subpar to moderate self-awareness capabilities. Our study underscores the potential of ChatGPT-4.0 in delivering accurate and comprehensive responses to ocular symptom inquiries. Future rigorous validation of their performance is crucial to ensure their reliability and appropriateness for actual clinical use.

13.
Ophthalmol Sci ; 3(4): 100392, 2023 Dec.
Article in English | MEDLINE | ID: mdl-38025163

ABSTRACT

Purpose: To examine the 6-year incidence of visual impairment (VI) and identify risk factors associated with VI in a multiethnic Asian population. Design: Prospective, population-based, cohort study. Participants: Adults aged ≥ 40 years were recruited from the Singapore Epidemiology of Eye Diseases cohort study at baseline. Eligible subjects were re-examined after 6 years. Subjects included in the final analysis had a mean age of 56.1 ± 8.9 years, and 2801 (50.5%) were female. Methods: All participants underwent standardized examination and interviewer-administered questionnaire at baseline. Incidences were standardized to the Singapore Population Census 2010. A Poisson binomial regression model was used to evaluate the associations between baseline factors and incident presenting VI. Main Outcome Measures: Incident presenting VI was assessed at the 6-year follow-up visit. Visual impairment (presenting visual acuity < 20/40), low vision (presenting visual acuity < 20/40 but ≥ 20/200), and blindness (presenting visual acuity < 20/200) were defined based on United States definition. Results: A total of 5551 subjects (2188 Chinese, 1837 Indians, and 1526 Malays) were evaluated, of whom 514 developed incident presenting VI over 6 years. Malays had a higher incidence of low vision and blindness (13.0%; 0.6%) than Indians (7.0%; 0.1%) and Chinese (7.7%; 0.2%). Among Malay individuals with VI at baseline, 52.8% remained visually impaired after 6 years, which was considerably higher than Chinese (32.4%) and Indians (37.2%). Older age (per decade; relative risk [RR] = 1.59), a history of cardiovascular disease (RR = 1.38), current smoking (RR = 1.31), smaller housing type (1- to 2-room public flat; RR = 2.01), and no formal education (RR = 1.63) at baseline were associated with a higher risk of incident VI (all P ≤ 0.027). Older age (> 60 years) contributed the highest population attributable risk to incident VI (27.1%), followed by lower monthly income (Singapore dollar < $2000; 26.4%) and smaller housing type (24.7%). Overall, undercorrected refractive error (49.1%) and cataract (82.6%) were leading causes for low vision and blindness, respectively. This was consistently observed across the 3 ethnicities. Conclusions: In this multiethnic Asian population, Malays had a higher VI incidence compared to Indians and Chinese. Leading causes of VI are mostly treatable, suggesting that more efforts are needed to further mitigate preventable visual loss. Financial Disclosures: The authors have no proprietary or commercial interest in any materials discussed in this article.

14.
EBioMedicine ; 95: 104770, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37625267

ABSTRACT

BACKGROUND: Large language models (LLMs) are garnering wide interest due to their human-like and contextually relevant responses. However, LLMs' accuracy across specific medical domains has yet been thoroughly evaluated. Myopia is a frequent topic which patients and parents commonly seek information online. Our study evaluated the performance of three LLMs namely ChatGPT-3.5, ChatGPT-4.0, and Google Bard, in delivering accurate responses to common myopia-related queries. METHODS: We curated thirty-one commonly asked myopia care-related questions, which were categorised into six domains-pathogenesis, risk factors, clinical presentation, diagnosis, treatment and prevention, and prognosis. Each question was posed to the LLMs, and their responses were independently graded by three consultant-level paediatric ophthalmologists on a three-point accuracy scale (poor, borderline, good). A majority consensus approach was used to determine the final rating for each response. 'Good' rated responses were further evaluated for comprehensiveness on a five-point scale. Conversely, 'poor' rated responses were further prompted for self-correction and then re-evaluated for accuracy. FINDINGS: ChatGPT-4.0 demonstrated superior accuracy, with 80.6% of responses rated as 'good', compared to 61.3% in ChatGPT-3.5 and 54.8% in Google Bard (Pearson's chi-squared test, all p ≤ 0.009). All three LLM-Chatbots showed high mean comprehensiveness scores (Google Bard: 4.35; ChatGPT-4.0: 4.23; ChatGPT-3.5: 4.11, out of a maximum score of 5). All LLM-Chatbots also demonstrated substantial self-correction capabilities: 66.7% (2 in 3) of ChatGPT-4.0's, 40% (2 in 5) of ChatGPT-3.5's, and 60% (3 in 5) of Google Bard's responses improved after self-correction. The LLM-Chatbots performed consistently across domains, except for 'treatment and prevention'. However, ChatGPT-4.0 still performed superiorly in this domain, receiving 70% 'good' ratings, compared to 40% in ChatGPT-3.5 and 45% in Google Bard (Pearson's chi-squared test, all p ≤ 0.001). INTERPRETATION: Our findings underscore the potential of LLMs, particularly ChatGPT-4.0, for delivering accurate and comprehensive responses to myopia-related queries. Continuous strategies and evaluations to improve LLMs' accuracy remain crucial. FUNDING: Dr Yih-Chung Tham was supported by the National Medical Research Council of Singapore (NMRC/MOH/HCSAINV21nov-0001).


Subject(s)
Benchmarking , Myopia , Humans , Child , Search Engine , Consensus , Language , Myopia/diagnosis , Myopia/epidemiology , Myopia/therapy
15.
Nat Chem ; 14(3): 274-283, 2022 03.
Article in English | MEDLINE | ID: mdl-35115657

ABSTRACT

Biomacromolecules are highly promising therapeutic modalities to treat various diseases. However, they suffer from poor cellular membrane permeability, limiting their access to intracellular targets. Strategies to overcome this challenge often employ nanoscale carriers that can get trapped in endosomal compartments. Here we report conjugated peptides that form pH- and redox-responsive coacervate microdroplets by liquid-liquid phase separation that readily cross the cell membrane. A wide range of macromolecules can be quickly recruited within the microdroplets, including small peptides, enzymes as large as 430 kDa and messenger RNAs (mRNAs). The therapeutic-loaded coacervates bypass classical endocytic pathways to enter the cytosol, where they undergo glutathione-mediated release of payload, the bioactivity of which is retained in the cell, while mRNAs exhibit a high transfection efficiency. These peptide coacervates represent a promising platform for the intracellular delivery of a large palette of macromolecular therapeutics that have potential for treating various pathologies (for example, cancers and metabolic diseases) or as carriers for mRNA-based vaccines.


Subject(s)
Endosomes , Peptides , Cytosol/metabolism , Endosomes/metabolism , Macromolecular Substances , Oxidation-Reduction , Peptides/metabolism
16.
Br J Ophthalmol ; 106(3): 381-387, 2022 03.
Article in English | MEDLINE | ID: mdl-33257306

ABSTRACT

AIMS: To evaluate the normative profiles for neuroretinal rim area (RA) in a multiethnic Asian population. METHODS: Subjects were recruited from the Singapore Epidemiology of Eye Diseases (2009-2015) study and underwent standardised examinations. RA measurements were performed using Cirrus high-definition optical coherence tomography (Carl Zeiss Meditec). Multivariable linear regression with generalised estimating equation model was used to evaluate the associations between demographic, systemic and ocular factors with RA. RESULTS: A total of 9394 eyes from 5116 subjects (1724 Chinese, 1463 Malay, 1929 Indian) were included in the final analysis. The mean (±SD) of RA was 1.28 (±0.23) mm2 for Chinese, 1.33 (±0.26) mm2 for Malays, and 1.23 (±0.23) mm2 for Indians. The 5th percentile value for RA was 0.94 mm2 for Chinese, 0.96 mm2 for Malay, and 0.89 mm2 for Indian. In multivariable analysis, following adjustment for age, gender, body mass index, diabetes mellitus, hyperlipidaemia, history of cataract surgery, axial length, intraocular pressure (IOP) and disc area, Indian eyes have smaller RA when compared with Malays (ß=-0.074; 95% CI -0.090 to -0.058; p<0.001) and Chinese (ß=-0.035; 95% CI -0.051 to -0.019; p<0.001), respectively. Additionally, older age (per decade, ß=-0.022), male gender (ß=-0.031), longer axial length (per mm, ß=-0.025), spherical equivalent (per negative dioptre, ß=-0.005), higher IOP (per mm Hg, ß=-0.009) were associated with smaller RA (all p≤0.004). CONCLUSION: In this multiethnic population-based study, we observed significantly smaller RA in Indian eyes, compared with Chinese and Malays. This indicates the need of a more refined ethnic-specific RA normative databases among Asians.


Subject(s)
Glaucoma , Optic Disk , Asian People , Glaucoma/epidemiology , Humans , Male , Singapore/epidemiology , Tomography, Optical Coherence/methods
17.
Sci Rep ; 11(1): 501, 2021 01 12.
Article in English | MEDLINE | ID: mdl-33436813

ABSTRACT

We evaluated the 6-year incidence and risk factors of pterygium in a multi-ethnic Asian population. Participants who attended the baseline visit of the Singapore Epidemiology of Eye Diseases Study (year 2004-2011) and returned six years later, were included in this study. Pterygium was diagnosed based on anterior segment photographs. Incident pterygium was defined as presence of pterygium at 6-year follow-up in either eye, among individuals without pterygium at baseline. Multivariable logistic regression models were used to determine factors associated with incident pterygium, adjusting for baseline age, gender, ethnicity, body mass index, occupation type, educational level, income status, smoking, alcohol consumption, presence of hypertension, diabetes and hyperlipidemia. The overall age-adjusted 6-year incidence of pterygium was 1.2% (95% confidence interval [CI] 1.0-1.6%); with Chinese (1.9%; 95% CI 1.4%-2.5%) having the highest incidence rate followed by Malays (1.4%; 95% CI 0.9%-2.1%) and Indians (0.3%; 95% CI 0.3-0.7%). In multivariable analysis, Chinese (compared with Indians; odds ratio [OR] = 4.21; 95% CI 2.12-9.35) and Malays (OR 3.22; 95% CI 1.52-7.45), male (OR 2.13; 95% CI 1.26-3.63), outdoor occupation (OR 2.33; 95% CI 1.16-4.38), and smoking (OR 0.41; 95% CI 0.16-0.87) were significantly associated with incident pterygium. Findings from this multi-ethnic Asian population provide useful information in identifying at-risk individuals for pterygium.


Subject(s)
Asian People/statistics & numerical data , Conjunctiva/abnormalities , Ethnicity/statistics & numerical data , Pterygium/epidemiology , Pterygium/pathology , Adult , Aged , Conjunctiva/pathology , Female , Humans , Incidence , Male , Middle Aged , Risk Factors , Singapore/epidemiology
18.
Br J Ophthalmol ; 105(5): 669-673, 2021 05.
Article in English | MEDLINE | ID: mdl-32675061

ABSTRACT

AIMS: To determine the association between albuminuria and primary open-angle glaucoma (POAG). METHODS: Participants of the Singapore Chinese Eye study were recruited and underwent standardised ocular and systemic examinations. Albuminuria was determined using urinary albumin-to-creatinine ratio (UACR, mg/g) based on random spot urinary albumin and creatinine measurements. POAG was defined using the International Society of Geographic and Epidemiological Ophthalmology classification. Multivariable logistic regression with generalised estimating equation model was used to evaluate the association between albuminuria and POAG, while accounting for correlation between eyes. RESULTS: A total of 3009 Chinese adults (5963 eyes), aged 40-80 years, were included in this study, of which, 52 subjects (75 eyes) had POAG. Higher UACR (per 50 mg/g increase) was independently associated with POAG (OR=1.04, 95% CI 1.01 to 1.07, p=0.003) following adjustment for age, gender, intraocular pressure, diabetes mellitus, hyperlipidaemia, hypertension, anti-hypertensive medication, history of cardiovascular disease, current smoking status, alcohol intake, body mass index and estimated glomerular filtration rate. Further stratification revealed that individuals with macroalbuminuria were 8.00 times likely to have POAG (95% CI 2.97 to 21.54, p<0.001), compared with those with normoalbuminuria. Microalbuminuria was not significantly associated with POAG (OR=0.49, 95% CI 0.19 to 1.29, p=0.150). The association between macroalbuminuria and POAG remained significant among individuals who were diabetic (OR=9.89, 95% CI 2.49 to 39.30, p=0.001) and hypertensive (OR=8.39, 95% CI 3.07 to 22.94, p<0.001). CONCLUSION: In this population-based study of Chinese adults, albuminuria was independently associated with POAG. Our findings provide further understanding on the pathogenesis of POAG and may potentially help to better identify individuals at risk of POAG.


Subject(s)
Albuminuria/etiology , Glaucoma, Open-Angle/complications , Glomerular Filtration Rate/physiology , Intraocular Pressure/physiology , Population Surveillance , Adult , Aged , Aged, 80 and over , Albuminuria/ethnology , Albuminuria/physiopathology , China/ethnology , Cross-Sectional Studies , Female , Glaucoma, Open-Angle/ethnology , Glaucoma, Open-Angle/physiopathology , Humans , Incidence , Male , Middle Aged , Risk Factors , Singapore/epidemiology , Visual Fields/physiology
19.
Acta Biomater ; 110: 221-230, 2020 07 01.
Article in English | MEDLINE | ID: mdl-32422317

ABSTRACT

Liver cancer is an aggressive malignancy associated with high levels of mortality and morbidity. Doxorubicin (Dox) is often used to slow down liver cancer progression; however its efficacy is limited, and its severe side effects prevent its routine use at therapeutic concentrations. We present a biomimetic peptide that coacervates into micro-droplets, within which both Dox and magnetic nanoparticles (MNPs) can be sequestered. These Dox-loaded Magnetic Coacervates (DMCs) can be used for thermo-chemotherapy, with the controlled release of Dox triggered by an external Alternating Magnetic Field (AMF). The DMCs are internalized by the cells via an energy-independent mechanism which is not based on endocytosis. Application of AMF generates a temperature of 45 °C within the DMCs, triggering their disassembly and the simultaneous release of Dox, thereby resulting in dual hyperthermia and chemotherapy for more efficient cancer therapy. In vitro studies conducted under AMF reveal that DMCs are cytocompatible and effective in inducing HepG2 liver cancer cell death. Thermo-chemotherapy treatment against HepG2 cells is also shown to be more effective compared to either hyperthermia or chemotherapy treatments alone. Thus, our novel peptide DMCs can open avenues in theranostic strategies against liver cancer through programmable, wireless, and remote control of Dox release. STATEMENT OF SIGNIFICANCE: Simultaneous administration of chemical and thermal therapy (thermo-chemotherapy) is more effective in inducing liver cancer cell death and improving survival rate. Thus, there is a keen interest in developing suitable carriers for thermo-chemotherapy. Coacervate micro-droplets display significant advantages, including high loading capacity, fast self-assembly in aqueous environments, and liquid-like behavior. However, they have not yet been explored as carriers for thermo-chemotherapy. Here, we demonstrate that peptide coacervate micro-droplets can co-encapsulate Dox and magnetic nanoparticles and cross the cell membrane. Applying an alternating magnetic field to cells containing drug-loaded coacervates triggers the release of Dox as well as the localized heating by magnetic hyperthermia, resulting in efficient liver cancer cell death by dual thermo-chemotherapy.


Subject(s)
Hyperthermia, Induced , Liver Neoplasms , Cell Line, Tumor , Doxorubicin/pharmacology , Humans , Hyperthermia , Liver Neoplasms/drug therapy , Peptides/pharmacology
20.
Cardiovasc Res ; 116(7): 1357-1371, 2020 06 01.
Article in English | MEDLINE | ID: mdl-31566660

ABSTRACT

AIMS: A robust inflammatory response to tissue injury is a necessary part of the repair process but the deposition of scar tissue is a direct downstream consequence of this response in many tissues including the heart. Adult zebrafish not only possess the capacity to regenerate lost cardiomyocytes but also to remodel and resolve an extracellular scar within tissues such as the heart, but this scar resolution process remains poorly understood. This study aims to characterize the scarring and inflammatory responses to cardiac damage in adult zebrafish in full and investigate the role of different inflammatory subsets specifically in scarring and scar removal. METHODS AND RESULTS: Using stable transgenic lines, whole organ imaging and genetic and pharmacological interventions, we demonstrate that multiple inflammatory cell lineages respond to cardiac injury in adult zebrafish. In particular, macrophage subsets (tnfα+ and tnfα-) play prominent roles with manipulation of different phenotypes suggesting that pro-inflammatory (tnfα+) macrophages promote scar deposition following cardiac injury whereas tnfα- macrophages facilitate scar removal during regeneration. Detailed analysis of these specific macrophage subsets reveals crucial roles for Csf1ra in promoting pro-inflammatory macrophage-mediated scar deposition. Additionally, the multifunctional cytokine Osteopontin (Opn) (spp1) is important for initial scar deposition but also for resolution of the inflammatory response and in late-stage ventricular collagen remodelling. CONCLUSIONS: This study demonstrates the importance of a correctly balanced inflammatory response to facilitate scar deposition during repair but also to allow subsequent scar resolution, and full cardiac regeneration, to occur. We have identified Opn as having both pro-fibrotic but also potentially pro-regenerative roles in the adult zebrafish heart, driving Collagen deposition but also controlling inflammatory cell resolution.


Subject(s)
Cell Lineage , Cicatrix/pathology , Heart Injuries/pathology , Macrophages/pathology , Myocardium/pathology , Ventricular Remodeling , Animals , Animals, Genetically Modified , Cicatrix/metabolism , Cicatrix/physiopathology , Collagen/metabolism , Disease Models, Animal , Gene Expression Regulation , Heart Injuries/metabolism , Heart Injuries/physiopathology , Macrophages/metabolism , Myocardium/metabolism , Osteopontin/genetics , Osteopontin/metabolism , Phenotype , Protein-Tyrosine Kinases/genetics , Protein-Tyrosine Kinases/metabolism , Receptor Protein-Tyrosine Kinases , Signal Transduction , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/metabolism , Zebrafish , Zebrafish Proteins/genetics , Zebrafish Proteins/metabolism
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