Glucose-mediated de novo lipogenesis in photoreceptors drives early diabetic retinopathy.

Diabetic retinopathy (DR) is an increasingly frequent cause of blindness across populations; however, the events that initiate pathophysiology of DR remain elusive. Strong preclinical and clinical evidence suggests that abnormalities in retinal lipid metabolism caused by diabetes may account for the origin of this disease. A major arm of lipid metabolism, de novo biosynthesis, is driven by elevation in available glucose, a common thread binding all forms of vision loss in diabetes. Therefore, we hypothesized that aberrant retinal lipid biogenesis is an important promoter of early DR. In murine models, we observed elevations of diabetes-associated retinal de novo lipogenesis ∼70% over control levels. This shift was primarily because of activation of fatty acid synthase (FAS), a rate-limiting enzyme in the biogenic pathway. Activation of FAS was driven by canonical glucose-mediated disinhibition of acetyl-CoA carboxylase, a major upstream regulatory enzyme. Mutant mice expressing gain-of-function FAS demonstrated increased vulnerability to DR, whereas those with FAS deletion in rod photoreceptors maintained preserved visual responses upon induction of diabetes. Excess retinal de novo lipogenesis-either because of diabetes or because of FAS gain of function-was associated with modestly increased levels of palmitate-containing phosphatidylcholine species in synaptic membranes, a finding with as yet uncertain significance. These findings implicate glucose-dependent increases in photoreceptor de novo lipogenesis in the early pathogenesis of DR, although the mechanism of deleterious action of this pathway remains unclear.

Bacillus coagulans-associated severe necrotizing scleral infection.

Purpose: We describe a case of severe scleritis possibly caused by Bacillus coagulans. Observations: Conventional laboratory evaluation was inconclusive. The associated organism was identified with metagenomic RNA deep sequencing (MDS). The infection resolved with trimethoprim-sulfamethoxazole treatment. Conclusions: This case demonstrates the utility of unbiased, high-throughput sequencing for infectious scleritis.

The effect of short-term preoperative nutritional intervention for cleft surgery eligibility.

BACKGROUND: Children with orofacial clefts are highly susceptible to malnutrition, with severe malnutrition restricting their eligibility to receive safe surgery. Ready-to-use therapeutic foods (RUTF) are an effective treatment for malnutrition; however, the effectiveness has not been demonstrated in this patient population prior to surgery. We studied the effectiveness of short-term RUTF use in transitioning children with malnutrition, who were initially ineligible for surgery, into surgical candidates. METHODS: A cohort of patients from Ghana, Honduras, Malawi, Madagascar, Nicaragua, and Venezuela enrolled in a nutrition program were followed by Operation Smile from June 2017 to January 2020. Age, weight, and length/height were tracked at each visit. Patients were included until they were sufficiently nourished (Z > = -1) with a secondary outcome of receiving surgery. The study was part of a collaborative program between Operation Smile (NGO), Birdsong Peanuts (peanut shellers and distributors), and MANA Nutrition (RUTF producer). RESULTS: A total of 556 patients were recruited between June 2017 and January 2020. At baseline 28.2% (n = 157) of patients were diagnosed with severe, 21.0% (n = 117) moderate, and 50.7% (n = 282) mild malnutrition. 324 (58.3%) presented for at least one return visit. Of those, 207 (63.7%) reached optimal nutrition status. By visit two, the mean z-score increased from -2.5 (moderate) to -1.7 (mild) (p < 0·001). The mean time to attain optimal nutrition was 6 weeks. There was a significant difference in the proportion of patients who improved by country(p < 0.001). CONCLUSION: Malnutrition prevents many children with orofacial clefts in low- and middle-income countries from receiving surgical care even when provided for free. This creates an even larger disparity in access to surgery. In an average of 6 weeks with an approximate cost of $25 USD per patient, RUTF transitioned over 60% of patients into nutritionally eligible surgical candidates, making it an effective, short-term preoperative nutritional intervention. Through unique partnerships, the expansion of cost-effective, large-scale nutrition programs can play a pivotal role in ensuring those at the highest risk of living with unrepaired orofacial clefts receive timely and safe surgical care.

The role of smoke from cooking indoors over an open flame and parental smoking on the risk of cleft lip and palate: A case- control study in 7 low-resource countries.

BACKGROUND: Cleft is one of the most common birth defects globally and the lack of access to surgery means millions are living untreated. Smoke exposure from cooking occurs infrequently in developed countries but represents a high-proportion of smoke exposure in less-developed regions. We aimed to study if smoke exposure from cooking is associated with an increased risk in cleft, while accounting for other smoke sources. METHODS: We conducted a population-sampled case-control study of children with cleft lip and/or palate and healthy newborns from Vietnam, Philippines, Honduras, Nicaragua, Morocco, Congo, and Madagascar. Multivariable regression models were used to assess associations between maternal cooking during pregnancy, parental smoking, and household tobacco smoke with cleft. RESULTS: 2137 cases and 2014 controls recruited between 2012-2017 were included. While maternal smoking was uncommon (<1%), 58.3% case and 36.1% control mothers cooked over an open fire inside. Children whose mothers reported cook smoke exposure were 49% (95% confidence interval (CI) = 1.2-1.8) more likely to have a child with a cleft. This was consistent in five of seven countries. No significant associations were found for any other smoke exposure. CONCLUSIONS: Our finding of maternal cook smoke and cleft in low-resource countries, similar to maternal tobacco smoke in high-resource countries, may reflect a common etiology. This relationship was present across geographically diverse countries with variable socioeconomic statuses and access to care. Exposures specific to low-resource settings must be considered to develop public health strategies that address the populations at increased risk of living with cleft and inform the mechanisms leading to cleft development.

A Synonymous Exonic Splice Silencer Variant in IRF6 as a Novel and Cryptic Cause of Non-Syndromic Cleft Lip and Palate.

Missense, nonsense, splice site and regulatory region variants in interferon regulatory factor 6 (IRF6) have been shown to contribute to both syndromic and non-syndromic forms of cleft lip and/or palate (CL/P). We report the diagnostic evaluation of a complex multigeneration family of Honduran ancestry with a pedigree structure consistent with autosomal-dominant inheritance with both incomplete penetrance and variable expressivity. The proband's grandmother bore children with two partners and CL/P segregates on both sides of each lineage. Through whole-exome sequencing of five members of the family, we identified a single shared synonymous variant, located in the middle of exon 7 of IRF6 (p.Ser307Ser; g.209963979 G>A; c.921C>T). The variant was shown to segregate in the seven affected individuals and through three unaffected obligate carriers, spanning both sides of this pedigree. This variant is very rare, only being found in three (all of Latino ancestry) of 251,352 alleles in the gnomAD database. While the variant did not create a splice acceptor/donor site, in silico analysis predicted it to impact an exonic splice silencer element and the binding of major splice regulatory factors. In vitro splice assays supported this by revealing multiple abnormal splicing events, estimated to impact >60% of allelic transcripts. Sequencing of the alternate splice products demonstrated the unmasking of a cryptic splice site six nucleotides 5' of the variant, as well as variable utilization of cryptic splice sites in intron 6. The ectopic expression of different splice regulatory proteins altered the proportion of abnormal splicing events seen in the splice assay, although the alteration was dependent on the splice factor. Importantly, each alternatively spliced mRNA is predicted to result in a frame shift and prematurely truncated IRF6 protein. This is the first study to identify a synonymous variant as a likely cause of NS-CL/P and highlights the care that should be taken by laboratories when considering and interpreting variants.

Structural and Functional Associations of Macular Microcirculation in the Ganglion Cell-Inner Plexiform Layer in Glaucoma Using Optical Coherence Tomography Angiography.

PURPOSE: To quantify retinal microvasculature within the macular ganglion cell-inner plexiform layer (GCIPL) in primary open-angle glaucoma (POAG) and normal eyes, determine association of vessel parameters with structural and functional measures, and report diagnostic accuracy of vessel parameters. METHODS: POAG and normal patients underwent 6×6 mm macula scans [Angioplex optical coherence tomography angiography (OCTA); Cirrus HD-OCT 5000]; and Humphrey Field Analyzer II-i 24-2 visual field (VF). Prototype software performed semiautomatic segmentation to create GCIPL en face images, and quantified vessel area density (VAD), vessel skeleton density (VSD), and vessel complexity index (VCI) for the macula (globally, hemifields, and 6 focal sectors). Linear regression assessed association of OCTA parameters with VF mean deviation (MD) and GCIPL thickness globally and focally. RESULTS: A total of 34 POAG and 21 normal eyes were studied. VAD, VSD, and VCI were reduced in POAG versus normal (0.463 vs. 0.486, P=0.00029; 0.230 vs. 0.219, P=0.0014; 1.15 vs. 1.09, P=0.0044, respectively), with a trend of worsening with increased POAG severity. Reduced global VF MD was associated with reduced VAD and VCI, controlling for age and intereye correlation (P=0.0060, 0.0080; R=0.205, 0.211). Both superior and inferior hemifield MD were associated with corresponding VAD, VSD, and VCI (all P<0.007; R ranged from 0.12 to 0.29). Global GCIPL thickness was not associated with global OCTA parameters, and only inferior sector GCIPL thickness was associated with corresponding VAD, VSD, and VCI (P<0.05; R ranged from 0.15 to 0.16). Area under curves for VAD, VSD, and VCI were fair to good (0.83, 0.79, 0.82; respectively; P<0.0001). CONCLUSIONS: Glaucomatous eyes had reduced GCIPL microcirculation. OCTA parameters had stronger associations with functional rather than structural measures of glaucoma. This observation deserves further study.

Peripapillary microvasculature in the retinal nerve fiber layer in glaucoma by optical coherence tomography angiography: focal structural and functional correlations and diagnostic performance.

PURPOSE: To quantify peripapillary microvasculature within the retinal nerve fiber layer (RNFL) in primary open-angle glaucoma (POAG) and normal eyes, determine association of perfusion parameters with structural and functional measures, and report diagnostic accuracy of perfusion parameters. PATIENTS AND METHODS: POAG and normal patients underwent 6×6 mm2 optic nerve head scans (Angioplex optical coherence tomography angiography [OCTA]; Cirrus HD-OCT 5000) and Humphrey Field Analyzer II-i 24-2 visual field (VF) testing. Prototype software performed semiautomatic segmentation to create RNFL en face images and quantified vessel area density (VAD), vessel skeleton density (VSD), and vessel complexity index (VCI) in the optic nerve head globally and focally. Generalized estimating equations models assessed association of OCTA parameters with VF mean deviation (MD) and RNFL thickness. RESULTS: Thirty-eight POAG and 17 normal eyes were studied. Global VAD, VSD, and VCI were reduced in mild POAG vs normal (P<0.02) and moderate-severe vs mild POAG (P<0.04). Stepwise focal reductions across disease stage were demonstrated for OCTA parameters in the inferior hemisphere (P<0.05); reduction in OCTA parameters in mild POAG vs normal was demonstrated in inferior and superior quadrants (P<0.05). Reduced global VF MD was associated with reduced VAD, VSD, and VCI (P=0.0007, 0.0013, <0.0001; R 2=0.449, 0.312, 0.399, respectively), and global RNFL thickness was associated with VAD, VSD, and VCI (P<0.0001; R 2=0.499, 0.524, 0.542), superior and inferior hemifield MD were associated with corresponding VAD, VSD, and VCI (P≤0.001; R 2 from 0.208 to 0.513). RNFL thickness in all quadrants was associated with corresponding OCTA parameters (P<0.05; R 2 from 0.213 to 0.394), except temporal VAD and VCI. Area under curves for VAD, VSD, and VCI demonstrated good diagnostic ability (0.868, 0.855, 0.868; P<0.0001). CONCLUSION: Glaucomatous eyes showed stepwise reductions in RNFL microcirculation across severity; focal reductions in the inferior hemisphere and inferior and superior quadrants were most significant. OCTA parameters had stronger associations with structural rather than functional measures of glaucoma.

Utility of optical coherence tomography angiography in detecting glaucomatous damage in a uveitic patient with disc congestion: A case report.

PURPOSE: To report a case of uveitic glaucoma with a congested optic disc where optical coherence tomography angiography (OCT-A) provided diagnostic utility in assessing glaucomatous damage but optical coherence tomography (OCT) alone had limited utility. OBSERVATIONS: We report a case of a 33-year-old Caucasian female referred to the USC Roski Eye Institute for uncontrolled intraocular pressure (IOP) in the left eye. She was managed by an outside provider for 6 months, where her IOP ranged from 28 to 42 mm Hg in the left eye on maximally tolerated medical therapy. Her clinical exam was consistent with Herpes family trabeculitis, optic nerve congestion, and possible glaucomatous damage. Initial evaluation of the optic nerve by standard modalities (fundus exam and OCT) was limited by optic nerve congestion; however, OCT-A showed peripapillary hypoperfusion, as commonly observed in glaucomatous eyes. She underwent aqueous shunt implantation for elevated IOPs poorly controlled by medications. CONCLUSIONS AND IMPORTANCE: OCT-A can be a useful tool in the evaluation of glaucoma in instances where disc congestion masks both nerve excavation and retinal nerve fiber thinning normally seen on exam and on standard OCT of the optic nerve.