A community-based strategy to eliminate hepatitis C among people who inject drugs in Vietnam.

Background: Towards hepatitis C elimination among people who inject drugs (PWID), we assessed the effectiveness of a strategy consisting of a community-based respondent-driven sampling (RDS) as wide screening, a simplified and integrated hospital-based care, and prevention of reinfection supported by community-based organisations (CBO), in Hai Phong, Vietnam. Methods: Adults who injected heroin were enrolled in a RDS survey implemented in two CBO premises. Rapid HIV and HCV tests were done on site, and blood was taken for HCV RNA testing. Those with detectable HCV RNA were referred with CBO support to three public hospitals for 12-week sofosbuvir/daclatasvir, plus ribavirin for patients with cirrhosis. Participants were followed-up 12 weeks post-treatment (SVR12) and 48 weeks after enrolment. The primary endpoint was the rate of undetectable HCV RNA participants at 48 weeks. Findings: Among the 1444 RDS survey participants, 875 had hepatitis C. Their median age was 41 years (IQR 36-47), 96% were males, 36% were HIV-coinfected. Overall, 686 (78.4%) started sofosbuvir/daclatasvirs, and 629 of the 647 (97.2%) patients tested at SVR12 were cured. At week 48 (581/608) 95.6% had undetectable HCV RNA, representing 66.4% of all PWID identified with hepatitis C. The reinfection rate after SVR12 was 4/100 person-years (95% CI: 2-7). Interpretation: Our strategy, involving CBO and addressing all steps from wide HCV screening to prevention of reinfection, stands as a promising approach to eliminate HCV among PWID in low and middle-income countries. Funding: France ANRS|MIE (#ANRS12380). The RDS survey was implemented with grants from the NIDA (#R01DA041978) and ANRS|MIE (#ANRS12353).

A community-based intervention to decrease the prevalence of HIV viremia among people who inject drugs in Vietnam.

Background: In most low-to-middle-income countries, HIV control at the population level among people who inject drugs (PWID) remains a major challenge. We aimed to demonstrate that an innovative intervention can identify HIV-positive PWID in the community who are not treated efficiently, and get them treated efficiently. Methods: Between 2016 and 2020, we implemented an intervention consisting of mass HIV screening of PWID using three annual respondent-driven sampling surveys (RDSS) and a post-intervention evaluation RDSS in community-based organisation (CBO) sites, coupled with peer support to facilitate/improve access to antiretroviral and methadone therapy in Haiphong, Vietnam. The primary outcome was the proportion of identified uncontrolled HIV-positive PWID who achieved viral control. We also estimated the potential effect of the intervention on the proportion of PWID with HIV RNA >1000 copies/mL among all PWID during the study period. Findings: Over the three RDSS, 3150 different PWID were screened, i.e. two-thirds of the estimated population size. They all injected heroin, their median age was of 39 years, 95% were male, 26.5% were HIV-infected, and 78.6% of the latter had HIV RNA ≤1000 copies/mL. Among the 177 PWID identified with an unsuppressed viral load, 73 (41.2%) achieved viral suppression at the final visit. HIV viremia decreased from 7.2% at baseline to 2.9% at the final RDSS (p<0.001). Up to 42% of this observed reduction may be explained by the intervention, in the absence of any external intervention targeting PWID during the study period. Interpretation: Mass community-based screening using RDSS coupled with CBO support is a powerful tool to rapidly identify untreated HIV-positive PWID and (re)link them to care. Funding: NIDA (USA) and ANRS (France).

Multicenter study on the genetics of glomerular diseases among southeast and south Asians: Deciphering Diversities - Renal Asian Genetics Network (DRAGoN).

Multinational studies have reported monogenic etiologies in 25%-30% of children with steroid-resistant nephrotic syndrome. Such large studies are lacking in Asia. We established Deciphering Diversities: Renal Asian Genetics Network (DRAGoN) and aimed to describe the genetic and clinical spectrums in Asians. We prospectively studied a cohort of 183 probands with suspected genetic glomerulopathies from South and Southeast Asia, of whom 17% had positive family history. Using multi-gene panel sequencing, we detected pathogenic variants in 26 (14%) probands, of whom one-third had COL4A4 or COL4A5 variants (n = 9, 5%). Of those with COL4A5 defects, only 25% had features suggestive of Alport syndrome. Besides traditional predictors for genetic disease (positive family history and extrarenal malformations), we identified novel predictors, namely older age (6.2 vs. 2.4 years; p = 0.001), hematuria (OR 5.6; 95% CI 2.1-14.8; p < 0.001), and proteinuria in the absence of nephrotic syndrome (OR 4.6; 95% CI 1.8-11.8; p = 0.001) at first manifestation. Among patients who first presented with proteinuria without nephrotic syndrome, the genetic diagnostic rates were >60% when a second risk factor (positive family history or extrarenal manifestation) co-existed. The genetic spectrum of glomerulopathies appears different in Asia. Collagen IV genes may be included in sequencing panels even when suggestive clinical features are absent.

How has the COVID-19 epidemic affected the risk behaviors of people who inject drugs in a city with high harm reduction service coverage in Vietnam? A qualitative investigation.

INTRODUCTION: The COVID-19 outbreak disproportionally affects vulnerable populations including people who inject drugs (PWID). Social distancing and stay-at-home orders might result in a lack of access to medical and social services, poorer mental health, and financial precariousness, and thus, increases in HIV and HCV risk behaviors. This article explores how the HIV/HCV risk behaviors of PWID in Haiphong, a city with high harm reduction service coverage in Vietnam, changed during the early phase of the COVID-19 pandemic, and what shaped such changes, using the risk environment framework. METHOD: We conducted three focus group discussions with peer outreach workers in May 2020 at the very end of the first lockdown, and 30 in-depth interviews with PWID between September and October 2020, after the second wave of infection in Vietnam. Discussions and interviews centered on the impact of the COVID-19 pandemic on their lives, and how their drug use and sexual behaviors changed as a result of the pandemic. RESULTS: The national shutdown of nonessential businesses due to the COVID-19 epidemic caused substantial economic challenges to participants, who mostly were in a precarious financial situation before the start of the epidemic. Unsafe injection is no longer an issue among our sample of PWID in Haiphong thanks to a combination of different factors, including high awareness of injection-related HIV/HCV risk and the availability of methadone treatment. However, group methamphetamine use as a means to cope with the boredom and stress related to COVID-19 was common during the lockdown. Sharing of smoking equipment was a standard practice. Female sex workers, especially those who were active heroin users, suffered most from COVID-related financial pressure and may have engaged in unsafe sex. CONCLUSION: While unsafe drug injection might no longer be an issue, group methamphetamine use and unsafe sex were the two most worrisome HIV/HCV risk behaviors of PWID in Haiphong during the social distancing and lockdown periods. These elevated risks could continue beyond the enforced lockdown periods, given PWID in general, and PWID who are also sex workers in particular, have been disproportionately affected during the global crisis.

Determinants of lamina cribrosa depth in healthy Asian eyes: the Singapore Epidemiology Eye Study.

AIM: To investigate the determinants of lamina cribrosa depth (LCD) in healthy eyes of Chinese and Indian Singaporean adults. METHODS: The optic nerve head (ONH) of the right eye of 1396 subjects (628 Chinese and 768 Indian subjects) was imaged with optical coherence tomography (OCT, Spectralis, Heidelberg, Germany). LCD was defined as the distance from the Bruch's membrane opening (LCD-BMO) or the peripapillary sclera (LCD-PPS) reference plane to the laminar surface. A linear regression model was used to evaluate the relationship between the LCD and its determinants. RESULTS: Both LCDs were significantly different between the two races (LCD-BMO: 421.95 (95% CI 365.32 to 491.79) µm in Chinese vs 430.39 (367.46-509.81) µm in Indians, p=0.021; and LCD-PPS: 353.34 (300.98-421.45) µm in Chinese vs 376.76 (313.39-459.78) µm in Indians, p<0.001). In the multivariable regression analysis, the LCD-PPS of the whole cohort was independently associated with females (ß=-31.93, p<0.001), Indians subjects (ß=21.39, p=0.004) (Chinese as the reference), axial length (Axl) (ß=-6.68, p=0.032), retinal nerve fibre layer thickness (RNFL) (ß=0.71, p=0.019), choroidal thickness (ChT) (ß=0.41, p<0.001), vertical cup disc ratio (VCDR) (ß=24.42, p<0.001) and disc size (ß=-60.75, p=0.001). For every 1 year older in age, the LCD-PPS was deeper on average by 1.95 µm in Chinese subjects (p=0.01) but there was no association in Indians subjects (p=0.851). CONCLUSIONS: The LCD was influenced by age, gender, race, Axl, RNFL, ChT, VCDR and disc size. This normative LCD database may facilitate a more accurate assessment of ONH cupping using OCT in Asian populations.

Systemic hypertension associated retinal microvascular changes can be detected with optical coherence tomography angiography.

A major complication of hypertension is microvascular damage and capillary rarefaction is a known complication of hypertensive end-organ damage which confers a higher risk of systemic disease such as stroke and cardiovascular events. Our aim was to study the effect of hypertension on the retinal microvasculature using non-invasive optical coherence tomography angiography (OCTA). We performed a case-control study of 94 eyes of 94 participants with systemic hypertension and 46 normal control eyes from the Singapore Chinese Eye Study using a standardized protocol to collect data on past medical history of hypertension, including the number and type of hypertensive medications and assessed mean arterial pressure. Retinal vascular parameters were measured in all eyes using OCTA. In the multivariate analysis adjusting for confounders, compared to controls, eyes of hypertensive patients showed a decrease in the macular vessel density at the level of the superficial [OR 0.02; 95% CI, 0 to 0.64; P 0.027] and deep venous plexuses [OR 0.03; 95% CI, 0 to 0.41; P 0.009] and an increase in the deep foveal avascular zone. This shows that hypertension is associated with reduced retinal vessel density and an increased foveal avascular zone, especially in the deep venous plexus, as seen on OCTA and there is a potential role in using OCTA as a clinical tool to monitor hypertensive damage and identifying at risk patients.

Compensation of retinal nerve fibre layer thickness as assessed using optical coherence tomography based on anatomical confounders.

BACKGROUND/AIMS: To compensate the retinal nerve fibre layer (RNFL) thickness assessed by spectral-domain optical coherence tomography (SD-OCT) for anatomical confounders. METHODS: The Singapore Epidemiology of Eye Diseases is a population-based study, where 2698 eyes (1076 Chinese, 704 Malays and 918 Indians) with high-quality SD-OCT images from individuals without eye diseases were identified. Optic disc and macular cube scans were registered to determine the distance between fovea and optic disc centres (fovea distance) and their respective angle (fovea angle). Retinal vessels were segmented in the projection images and used to calculate the circumpapillary retinal vessel density profile. Compensated RNFL thickness was generated based on optic disc (ratio, orientation and area), fovea (distance and angle), retinal vessel density, refractive error and age. Linear regression models were used to investigate the effects of clinical factors on RNFL thickness. RESULTS: Retinal vessel density reduced significantly with increasing age (1487±214 µm in 40-49, 1458±208 µm in 50-59, 1429±223 µm in 60-69 and 1415±233 µm in ≥70). Compensation reduced the variability of RNFL thickness, where the effect was greatest for Chinese (10.9%; p<0.001), followed by Malays (6.6%; p=0.075) and then Indians (4.3%; p=0.192). Compensation reduced the age-related RNFL decline by 55% in all participants (ß=-3.32 µm vs ß=-1.50 µm/10 years; p<0.001). Nearly 62% of the individuals who were initially classified as having abnormally thin RNFL (outside the 99% normal limits) were later reclassified as having normal RNFL. CONCLUSIONS: RNFL thickness compensated for anatomical parameters reduced the variability of measurements and may improve glaucoma detection, which needs to be confirmed in future studies.

Six-year incidence and progression of diabetic retinopathy in Indian adults: the Singapore Indian Eye study.

AIMS: Diabetes is a major public health problem in migrants and ethnic minorities worldwide. We determined the incidence and risk factors of diabetic retinopathy (DR) in migrant Indians living in Singapore. METHODS: We included data from 759 Indian adults with diabetes, who participated in the baseline (aged 40-80 years, 2007-2009) and 6-year follow-up 2012-2015 of the Singapore Indian Eye Study. Retinal photographs were graded for the presence and severity of DR using modified Airlie House Classification. Incidence was assessed in participants who were free of DR at baseline visit (n=501), while progression in those with DR but free of proliferative DR at baseline visit (n=189). Risk factors included demographic, lifestyle, socioeconomic, family history, genes, duration of diabetes, glycaemic control, insulin use, ocular and clinical factors. RESULTS: The 6-year age-standardised DR incidence and progression were 21.89% and 33.45%, respectively. HbA1c (risk ratio (RR) 1.41, 95% CI 1.28 to 1.55 per unit increase), current smoking (RR 1.63, 95% CI 1.02 to 2.62) and insulin use (RR 2.63, 95% CI 1.44 to 4.82) were associated with higher incidence, whereas estimated cerebrospinal fluid pressure (RR 0.90, 95% CI 0.82 to 0.98) and body mass index (BMI) (RR 0.74, 95% CI 0.60 to 0.93) were associated with lower incidence of DR. Higher HbA1c (RR 1.26, 95% CI 1.13 to 1.42), BMI (RR 1.26, 95% CI 1.02 to 1.56) and estimated cerebrospinal fluid pressure (RR 1.11, 95% CI 1.02 to 1.21) were associated with DR progression. The population attributable risk of HbA1c >8% was 41.29% and 49.63% for DR incidence and progression. CONCLUSION: DR incidence and progression in migrant Indians living in Singapore was more than double that reported in Indians living in urban India. Consistent with past studies, poor glycaemic control was an important predictor for incidence and progression of DR.

Racial differences and determinants of macular thickness profiles in multiethnic Asian population: the Singapore Epidemiology of Eye Diseases Study.

AIM: To evaluate racial differences, and ocular and systemic determinants of macular thickness (MT), measured by spectral-domain optical coherence tomography (SD-OCT) in a normal multiethnic Asian population. METHOD: MT was measured from a 6×6 mm2 central macular area using the Cirrus high-definition OCT (HD-OCT) (Carl Zeiss Meditec, Dublin, CA). The associations between ocular and systemic factors with MT were evaluated using linear regression analyses with generalised estimating equation models to account for intereye correlation. RESULTS: 7447 healthy eyes (2577 Chinese, 2072 Malays and 2798 Indians) of 4510 subjects were included. Multivariable analysis showed that older age (per decade, ß=-4.39), female gender (ß=-5.74), diabetes (ß=-1.10), chronic kidney disease (CKD) (ß=-3.21), longer axial length (per mm, ß=-2.34), flatter corneal curvature (per mm, ß=-1.79) and presence of cataract (ß=-0.94) were associated with thinner overall average MT (OMT) (all p≤0.026); higher total cholesterol (ß=0.44; p=0.010) was associated with thicker OMT. All these factors were also associated with thinner central subfield MT (CSMT) (all p≤0.001), except for cataract, total cholesterol and CKD. Meanwhile, longer axial length (ß=2.51; p<0.001) was associated with thicker CSMT. OMT (mean±SD) was thickest in Chinese (279.9±12.5 µm), followed by Malays (276.5±13.7 µm) and Indians (272.4±13.1 µm), with p≤0.003 for all interethnic comparisons. Similar trend was observed for CSMT. CONCLUSION: There are interethnic differences in MT profile among Asians, particularly between Chinese and Indians. Ocular and systemic factors affect MT measurements as well. This Asian-specific information may be incorporated into existing clinical interpretation of macular OCT scans to aid in improving the diagnostic and monitoring accuracy of macular diseases among Asians.

The Effect of Testing Reliability on Visual Field Sensitivity in Normal Eyes: The Singapore Chinese Eye Study.

PURPOSE: To quantitatively determine how the reliability indices in standard automated perimetry (SAP) affect the global indices of visual field (VF) results in nonglaucomatous eyes. DESIGN: Observational, cross-sectional study. PARTICIPANTS: A total of 830 adults aged 40 to 80 years, without visual impairment, glaucoma, significant cataract, and major eye diseases, were selected from the population-based Singapore Chinese Eye Study (SCES). METHODS: Study participants underwent a comprehensive and standardized ocular examination and VF assessment using a Humphrey Field Analyzer II (Carl Zeiss Meditec, Inc., Dublin, CA). The effects of the test reliability, as indicated by the false-negative (FN), false-positive (FP), and fixation loss (FL) rates, on global indices, as indicated by the mean deviation (MD) and pattern standard deviation (PSD), were analyzed with multivariable regression models. MAIN OUTCOME MEASURES: The MD and PSD. RESULTS: A total of 1828 VF results from 1235 normal eyes of 830 study subjects were included in the analyses. The multivariable regression analyses adjusted for age, gender, best-corrected visual acuity, and test duration showed that at lower frequencies of false answers (<15%), FNs decreased the MD (ß [change in decibels {dB} per 5% increment in false answers] = -0.71 dB; P < 0.001), whereas FPs increased the MD (ß = 0.65 dB; P < 0.001). At higher frequencies (≥15%), the false answers influenced the MD to a greater extent, where the ß for the associations with FN and FP rates was -1.15 and 1.26 dB, respectively (both P < 0.001). We also found that when FN rate was <15%, higher FN rate increased the PSD (ß = 0.51 dB; P < 0.001), and the effect was slightly larger when FN rate was ≥15% (ß = 0.71 dB; P < 0.001). The effect of FPs on PSD was observed only when FP rate was <15% (ß = -0.22 dB; P < 0.001). The FL had no associations with the MD, and had minimal effects on the PSD. CONCLUSIONS: We quantified the effect of unreliable responses on the MD and PSD in SAP. Our study may allow clinicians to estimate how VF results are affected by varying degrees of unreliability, instead of relying on cutoff values for reliability indices.

Forging links between human mental retardation-associated CNVs and mouse gene knockout models.

Rare copy number variants (CNVs) are frequently associated with common neurological disorders such as mental retardation (MR; learning disability), autism, and schizophrenia. CNV screening in clinical practice is limited because pathological CNVs cannot be distinguished routinely from benign CNVs, and because genes underlying patients' phenotypes remain largely unknown. Here, we present a novel, statistically robust approach that forges links between 148 MR-associated CNVs and phenotypes from approximately 5,000 mouse gene knockout experiments. These CNVs were found to be significantly enriched in two classes of genes, those whose mouse orthologues, when disrupted, result in either abnormal axon or dopaminergic neuron morphologies. Additional enrichments highlighted correspondences between relevant mouse phenotypes and secondary presentations such as brain abnormality, cleft palate, and seizures. The strength of these phenotype enrichments (>100% increases) greatly exceeded molecular annotations (<30% increases) and allowed the identification of 78 genes that may contribute to MR and associated phenotypes. This study is the first to demonstrate how the power of mouse knockout data can be systematically exploited to better understand genetically heterogeneous neurological disorders.

Reduced purifying selection prevails over positive selection in human copy number variant evolution.

Copy number variation is a dominant contributor to genomic variation and may frequently underlie an individual's variable susceptibilities to disease. Here we question our previous proposition that copy number variants (CNVs) are often retained in the human population because of their adaptive benefit. We show that genic biases of CNVs are best explained, not by positive selection, but by reduced efficiency of selection in eliminating deleterious changes from the human population. Of four CNV data sets examined, three exhibit significant increases in protein evolutionary rates. These increases appear to be attributable to the frequent coincidence of CNVs with segmental duplications (SDs) that recombine infrequently. Furthermore, human orthologs of mouse genes, which, when disrupted, result in pre- or postnatal lethality, are unusually depleted in CNVs. Together, these findings support a model of reduced purifying selection (Hill-Robertson interference) within copy number variable regions that are enriched in nonessential genes, allowing both the fixation of slightly deleterious substitutions and increased drift of CNV alleles. Additionally, all four CNV sets exhibited increased rates of interspecies chromosomal rearrangement and nucleotide substitution and an increased gene density. We observe that sequences with high G+C contents are most prone to copy number variation. In particular, frequently duplicated human SD sequence, or CNVs that are large and/or observed frequently, tend to be elevated in G+C content. In contrast, SD sequences that appear fixed in the human population lie more frequently within low G+C sequence. These findings provide an overarching view of how CNVs arise and segregate in the human population.

Genome-wide prediction of matrix attachment regions that increase gene expression in mammalian cells.

Gene transfer in eukaryotic cells and organisms suffers from epigenetic effects that result in low or unstable transgene expression and high clonal variability. Use of epigenetic regulators such as matrix attachment regions (MARs) is a promising approach to alleviate such unwanted effects. Dissection of a known MAR allowed the identification of sequence motifs that mediate elevated transgene expression. Bioinformatics analysis implied that these motifs adopt a curved DNA structure that positions nucleosomes and binds specific transcription factors. From these observations, we computed putative MARs from the human genome. Cloning of several predicted MARs indicated that they are much more potent than the previously known element, boosting the expression of recombinant proteins from cultured cells as well as mediating high and sustained expression in mice. Thus we computationally identified potent epigenetic regulators, opening new strategies toward high and stable transgene expression for research, therapeutic production or gene-based therapies.

Bias of selection on human copy-number variants.

Although large-scale copy-number variation is an important contributor to conspecific genomic diversity, whether these variants frequently contribute to human phenotype differences remains unknown. If they have few functional consequences, then copy-number variants (CNVs) might be expected both to be distributed uniformly throughout the human genome and to encode genes that are characteristic of the genome as a whole. We find that human CNVs are significantly overrepresented close to telomeres and centromeres and in simple tandem repeat sequences. Additionally, human CNVs were observed to be unusually enriched in those protein-coding genes that have experienced significantly elevated synonymous and nonsynonymous nucleotide substitution rates, estimated between single human and mouse orthologues. CNV genes encode disproportionately large numbers of secreted, olfactory, and immunity proteins, although they contain fewer than expected genes associated with Mendelian disease. Despite mouse CNVs also exhibiting a significant elevation in synonymous substitution rates, in most other respects they do not differ significantly from the genomic background. Nevertheless, they encode proteins that are depleted in olfactory function, and they exhibit significantly decreased amino acid sequence divergence. Natural selection appears to have acted discriminately among human CNV genes. The significant overabundance, within human CNVs, of genes associated with olfaction, immunity, protein secretion, and elevated coding sequence divergence, indicates that a subset may have been retained in the human population due to the adaptive benefit of increased gene dosage. By contrast, the functional characteristics of mouse CNVs either suggest that advantageous gene copies have been depleted during recent selective breeding of laboratory mouse strains or suggest that they were preferentially fixed as a consequence of the larger effective population size of wild mice. It thus appears that CNV differences among mouse strains do not provide an appropriate model for large-scale sequence variations in the human population.