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Guo X, Friedman DS, Repka MX, Collins ME. Visual acuity and refractive findings in children prescribed glasses from a school-based vision program. J AAPOS 2021;Abstract
PURPOSE: We report visual acuity improvement and refractive profiles in children prescribed glasses by a school-based vision program (SBVP) in Baltimore, Maryland. METHODS: In this cross-sectional analysis, pre-kindergarten through 8th grade students who failed vision screening underwent an eye examination. Students prescribed glasses are included. Visual acuity improvement was the difference between presenting and best-corrected visual acuity based on noncycloplegic manifest refraction. Clinically significant refractive error (CSRE) was defined as ≥0.75 D myopia, ≥2.00 D hyperopia without strabismus, ≥1.00 D hyperopia with esodeviation, or ≥1.50 D astigmatism AND presenting visual acuity ≤20/40 or ≥2-line difference with the better-seeing eye ≤20/30. Characteristics associated with greater visual acuity improvement were explored. RESULTS: Of the 4,972 students, mean age was 9.4 ± 2.7 years; 77% were black, and 18% were Hispanic. Myopia, hyperopia, astigmatism, and CSRE were found in 65%, 24%, 60%, and 46% students, respectively. In the better-seeing eyes, 70% gained ≥2 lines. Of students with CSRE, improvement of at least 5 lines in the worse-seeing eye increased from 30.9% in pre-kindergarten and kindergarten to 77.3% in 7th and 8th grade (Ptrend < 0.001). Students with CSRE had a higher rate of gaining at least 2 lines' improvement in their worse-seeing eyes compared with those without (98.7% vs 80.6%). Older students as well as blacks and Hispanics were more likely to have improvement of at least 2 lines. CONCLUSIONS: Most students prescribed glasses from our SBVP had clinically significant visual deficits corrected.
Tomita Y, Qiu C, Bull E, Allen W, Kotoda Y, Talukdar S, Smith LEH, Fu Z. Müller glial responses compensate for degenerating photoreceptors in retinitis pigmentosa. Exp Mol Med 2021;Abstract
Photoreceptor degeneration caused by genetic defects leads to retinitis pigmentosa, a rare disease typically diagnosed in adolescents and young adults. In most cases, rod loss occurs first, followed by cone loss as well as altered function in cells connected to photoreceptors directly or indirectly. There remains a gap in our understanding of retinal cellular responses to photoreceptor abnormalities. Here, we utilized single-cell transcriptomics to investigate cellular responses in each major retinal cell type in retinitis pigmentosa model (P23H) mice vs. wild-type littermate mice. We found a significant decrease in the expression of genes associated with phototransduction, the inner/outer segment, photoreceptor cell cilium, and photoreceptor development in both rod and cone clusters, in line with the structural changes seen with immunohistochemistry. Accompanying this loss was a significant decrease in the expression of genes involved in metabolic pathways and energy production in both rods and cones. We found that in the Müller glia/astrocyte cluster, there was a significant increase in gene expression in pathways involving photoreceptor maintenance, while concomitant decreases were observed in rods and cones. Additionally, the expression of genes involved in mitochondrial localization and transport was increased in the Müller glia/astrocyte cluster. The Müller glial compensatory increase in the expression of genes downregulated in photoreceptors suggests that Müller glia adapt their transcriptome to support photoreceptors and could be thought of as general therapeutic targets to protect against retinal degeneration.
Olafsson J, Lai X, Landsend ECS, Olafsson S, Parissi E, Utheim ØA, Raeder S, Badian RA, Lagali N, Dartt DA, Utheim TP. TheraPearl Eye Mask and Blephasteam for the treatment of meibomian gland dysfunction: a randomized, comparative clinical trial. Sci Rep 2021;11(1):22386.Abstract
Meibomian gland dysfunction (MGD) is the most common cause of dry eye disease (DED). In this study, we aimed to compare the effects of eyelid warming treatment using either TheraPearl Eye Mask (Bausch & Lomb Inc., New York, USA) or Blephasteam (Spectrum Thea Pharmaceuticals LTD, Macclesfield, UK) in a Norwegian population with mild to moderate MGD-related DED. An open label, randomized comparative trial with seventy patients (49 females, 21 males; mean age 53.6 years). Patients were randomly assigned to treatment with Blephasteam (n = 37) or TheraPearl (n = 33). All received a hyaluronic acid based artificial tear substitute (Hylo-Comod, Ursapharm, Saarbrücken, Germany). Patients were examined at baseline, and at three and six months initiation of treatment. Treatment efficacy was primarily evaluated by fluorescein breakup time (FBUT) and Ocular Surface Disease Index (OSDI) scores. Other outcome measures included ocular surface staining (OSS), Schirmer's test, and meibomian quality and expressibility. Baseline parameter values did not differ between the groups. After six months of treatment, Blephasteam improved FBUT by 3.9 s (p < 0.01) and OSDI by 13.7 (p < 0.01), TheraPearl improved FBUT by 2.6 s (p < 0.01) and OSDI by 12.6 (p < 0.01). No difference between treatments was detected at 6 months (p = 0.11 for FBUT and p = 0.71 for OSDI), nor were there differences in the other tested parameters between the treatment groups. Blephasteam and TheraPearl are equally effective in treating mild to moderate MGD in a Norwegian population after 6-months of treatment.Clinicaltrials.gov ID: NCT03318874; Protocol ID: 2014/1983; First registration: 24/10/2017.
Betzler BK, Gunasekeran DV, Kempen J, Smith JR, McCluskey P, Nguyen QD, Pavesio C, Gupta V, Agrawal R. The Historical Evolution of Ocular Tuberculosis: Past, Present, and Future. Ocul Immunol Inflamm 2021;:1-7.Abstract
Ocular involvement is a rare manifestation of tuberculosis. Four key issues historically faced by clinicians when diagnosing and treating ocular tuberculosis - diagnostic uncertainty, naturally heterogeneous presentations, limitations of existing laboratory diagnostic tools, and non-uniform treatment guidelines - continue to test today's physicians. Unparalleled scientific and clinical developments over the past century have greatly expanded the knowledge surrounding this challenging ophthalmic condition. Experience with large volumes of cases at tuberculosis-endemic centres has led to recent growth in knowledge and physician experience, perhaps more so in developing countries. Looking forward, the role of diverse new technologies, including artificial intelligence and proteomics, will advance ocular tuberculosis research. Efforts have been made to address the lack of standardized nomenclature, diagnostic uncertainty, and unvalidated, geographically variable treatment guidelines.
Magno MS, Olafsson J, Beining M, Moschowits E, Lagali N, Wolffsohn JS, Craig JP, Dartt DA, Vehof J, Utheim TP. Chambered warm moist air eyelid warming devices - a review. Acta Ophthalmol 2021;Abstract
BACKGROUND: Eyelid warming is an important treatment for meibomian gland dysfunction (MGD). Specialized chambered devices, using warm moist air have been developed. PURPOSE: To critically evaluate the literature on the safety and efficacy of chambered warm moist air devices in MGD treatment and pinpoint areas of future research. METHODS: PubMed and Embase were searched on 06 June 2021. The search term was '(warm OR heat OR steam OR goggle OR spectacle OR moist air) AND (meibomian OR MGD OR blepharitis OR eyelid OR dry eye OR DED)'. All relevant articles with available English full text were included. RESULTS: Eighteen articles assessing the application of chambered warm moist air eyelid warming devices were identified. In single-application studies, steam-based eyelid warming increased the eyelid temperature and improved symptoms, lipid layer thickness, and tear film breakup time (TBUT). In treatment studies, the steam-based devices improved TBUT and symptom scores. However, in the only randomized controlled trial (RCT) comparing chambered steam-based heat to hot towel treatment, there was no difference between groups for the primary outcome measure; the proportion of subjects noting symptom improvement after 4 weeks. CONCLUSION: Currently available chambered warm moist air eyelid warming devices are safe and effective at raising eyelid temperature to therapeutic levels and improving signs and symptoms of dry eye. However, it is not clear if they provide a greater benefit than other eyelid warming therapies. Further well-conducted RCTs comparing moist and dry heat devices should be conducted on patients across the range of DED severities and subtype spectrum.
Sena DF, Kilian R, Liu S-H, Rizzo S, Virgili G. Pneumatic retinopexy versus scleral buckle for repairing simple rhegmatogenous retinal detachments. Cochrane Database Syst Rev 2021;11:CD008350.Abstract
BACKGROUND: A rhegmatogenous retinal detachment (RRD) is a separation of the neurosensory retina from the retinal pigment epithelium caused by a full-thickness break associated with vitreous traction. While pneumatic retinopexy (PR), scleral buckle (SB), and vitrectomy are all well-received surgical interventions for eyes with RRD, their relative effectiveness has remained controversial. OBJECTIVES: To assess the effectiveness and safety of PR versus SB or PR versus a combination treatment of SB and vitrectomy for people with RRD and to summarize any data on economic measures and quality of life. SEARCH METHODS: We searched CENTRAL; which contains the Cochrane Eyes and Vision Trials Register; 2021, Issue 3); Ovid MEDLINE; Ovid Embase; and four other databases on 11 March 2021. We used no date or language restrictions in the electronic searches for trials. SELECTION CRITERIA: We included all randomized or quasi-randomized controlled trials comparing the effectiveness of PR versus SB (with or without vitrectomy) for eyes with RRD. DATA COLLECTION AND ANALYSIS: After screening for eligibility, two review authors independently extracted study characteristics, methods, and outcomes. We followed systematic review standards as set by Cochrane. MAIN RESULTS: In this update, we identified and included one new randomized controlled trial. Together with two trials from the 2015 version of the review, we included three trials (276 eyes of 274 participants) comparing the effectiveness of PR versus SB. None compared PR versus a combined treatment of SB and vitrectomy.  Of the three trials, one was a small study (published in 1996) with 20 participants (20 eyes) enrolled in Ireland and followed for a mean of 16 months; the second (published in 1989) included 196 participants (198 eyes) in the US followed for at least six months, and the third (published in 2021) was conducted in Italy and enrolled 58 participants (58 eyes) with a follow-up of 12 months. Overall, poor reporting quality resulted in unclear or high risks of bias.  We found low-certainty evidence that PR may achieve retinal reattachment slightly less often than SB (risk ratio [RR] 0.91, 95% confidence interval [CI] 0.81 to 1.02; I2 = 0%; 3 studies, 276 eyes). Eyes undergoing PR may also display a higher risk of recurrent retinal detachment (low-certainty evidence), but the RR estimates were very imprecise (RR 1.70, 95% CI 0.97 to 2.98; I2 = 0%; 3 studies, 276 eyes). All three studies described the final visual acuity (VA) after the two procedures. However, the results were reported using different metrics and could not be combined. One study (196 participants) reported the proportion of eyes with a final VA of 20/40 or greater and favored PR (RR 1.31, 95% CI 1.04 to 1.65; low-certainty evidence), whereas in the 2021 study, both groups showed an improvement in final VA and there was no evidence of a difference between the two (mean difference [MD] -0.03, 95% CI -0.25 to 0.19; low-certainty evidence). No study reported data on quality of life or economic measures. Postoperative safety outcomes generally favored PR versus SB (low/very low-certainty evidence); however, there was considerable uncertainty regarding the risk of any operative ocular adverse events (RR 0.55 CI 0.28 to 1.11; 276 eyes), glaucoma (RR 0.31, 95% CI 0.01 to 7.46; 198 eyes), macular pucker (RR 0.65, 95% CI 0.20 to 2.11; 256 eyes), proliferative vitreoretinopathy (RR 0.94, 95% CI 0.30 to 2.96; 276 eyes), and persistent diplopia (RR 0.24, 95% CI 0.03 to 2.09; 256 eyes). Eyes undergoing PR experienced fewer postoperative cataract developments (RR 0.40, 95% CI 0.21 to 0.75; 153 eyes), choroidal detachments (RR 0.17, 95% CI 0.05 to 0.57; 198 eyes), and myopic shift (RR 0.03, 95% CI 0.01 to 0.10; 256 eyes). AUTHORS' CONCLUSIONS: The current update confirms the findings of the previous review. PR may result in lower rates of reattachment and higher rates of recurrence than SB, but carries a lower burden of postoperative complications. The effects of these two procedures on other functional outcomes and quality of life remain uncertain. The available evidence remains insufficient and of low quality.
Cai LZ, Lin J, Starr MR, Obeid A, Ryan EH, Ryan C, Forbes NJ, Arias D, Ammar MJ, Patel LG, Capone A, Emerson GG, Joseph DP, Eliott D, Gupta OP, Regillo CD, Hsu J, Yonekawa Y, Yonekawa Y. PRO score: predictive scoring system for visual outcomes after rhegmatogenous retinal detachment repair. Br J Ophthalmol 2021;Abstract
BACKGROUND/AIMS: To compare risk factors for poor visual outcomes in patients undergoing primary rhegmatogenous retinal detachment (RRD) repair and to develop a scoring system. METHODS: Analysis of the Primary Retinal detachment Outcomes (PRO) study, a multicentre interventional cohort of consecutive primary RRD surgeries performed in 2015. The main outcome measure was a poor visual outcome (Snellen VA ≤20/200). RESULTS: A total of 1178 cases were included. The mean preoperative and postoperative logMARs were 1.1±1.1 (20/250) and 0.5±0.7 (20/63), respectively. Multivariable logistic regression identified preoperative risk factors predictive of poor visual outcomes (≤20/200), including proliferative vitreoretinopathy (PVR) (OR 1.26; 95% CI 1.13 to 1.40), history of antivascular endothelial growth factor (VEGF) injections (1.38; 1.11 to 1.71), >1-week vision loss (1.17; 1.08 to 1.27), ocular comorbidities (1.18; 1.00 to 1.38), poor presenting VA (1.06 per initial logMAR unit; 1.02 to 1.10) and age >70 (1.13; 1.04 to 1.23). The data were split into training (75%) and validation (25%) and a scoring system was developed and validated. The risk for poor visual outcomes was 8% with a total score of 0, 17% with 1, 29% with 2, 47% with 3, and 71% with 4 or higher. CONCLUSIONS: Independent risk factors were compared for poor visual outcomes after RRD surgery, which included PVR, anti-VEGF injections, vision loss >1 week, ocular comorbidities, presenting VA and older age. The PRO score was developed to provide a scoring system that may be useful in clinical practice.
Yemanyi F, Bora K, Blomfield AK, Wang Z, Chen J. Wnt Signaling in Inner Blood-Retinal Barrier Maintenance. Int J Mol Sci 2021;22(21)Abstract
The retina is a light-sensing ocular tissue that sends information to the brain to enable vision. The blood-retinal barrier (BRB) contributes to maintaining homeostasis in the retinal microenvironment by selectively regulating flux of molecules between systemic circulation and the retina. Maintaining such physiological balance is fundamental to visual function by facilitating the delivery of nutrients and oxygen and for protection from blood-borne toxins. The inner BRB (iBRB), composed mostly of inner retinal vasculature, controls substance exchange mainly via transportation processes between (paracellular) and through (transcellular) the retinal microvascular endothelium. Disruption of iBRB, characterized by retinal edema, is observed in many eye diseases and disturbs the physiological quiescence in the retina's extracellular space, resulting in vision loss. Consequently, understanding the mechanisms of iBRB formation, maintenance, and breakdown is pivotal to discovering potential targets to restore function to compromised physiological barriers. These unraveled targets can also inform potential drug delivery strategies across the BRB and the blood-brain barrier into retinas and brain tissues, respectively. This review summarizes mechanistic insights into the development and maintenance of iBRB in health and disease, with a specific focus on the Wnt signaling pathway and its regulatory role in both paracellular and transcellular transport across the retinal vascular endothelium.
Woodward AM, Feeley MN, Rinaldi J, Argüeso P. CRISPR/Cas9 genome editing reveals an essential role for basigin in maintaining a nonkeratinized squamous epithelium in cornea. FASEB Bioadv 2021;3(11):897-908.Abstract
One of the primary functions of nonkeratinized stratified squamous epithelia is to protect underlying tissues against chemical, microbial, and mechanical insult. Basigin is a transmembrane matrix metalloproteinase inducer commonly overexpressed during epithelial wound repair and cancer but whose physiological significance in normal epithelial tissue has not been fully explored. Here we used a CRISPR/Cas9 system to study the effect of basigin loss in a human cornea model of squamous epithelial differentiation. We find that epithelial cell cultures lacking basigin change shape and fail to produce a flattened squamous layer on the apical surface. This process is associated with the abnormal expression of the transcription factor SPDEF and the decreased biosynthesis of MUC16 and involucrin necessary for maintaining apical barrier function and structural integrity, respectively. Expression analysis of genes encoding tight junction proteins identified a role for basigin in promoting physiological expression of occludin and members of the claudin family. Functionally, disruption of basigin expression led to increased epithelial cell permeability as evidenced by the decrease in transepithelial electrical resistance and increase in rose bengal flux. Overall, these results suggest that basigin plays a distinct role in maintaining the normal differentiation of stratified squamous human corneal epithelium and could have potential implications to therapies targeting basigin function.
Gárriz A, Aubry S, Wattiaux Q, Bair J, Mariano M, Hatzipetrou G, Bowman M, Morokuma J, Ortiz G, Hamrah P, Dartt DA, Zoukhri D. Role of the Phospholipase C Pathway and Calcium Mobilization in Oxytocin-Induced Contraction of Lacrimal Gland Myoepithelial Cells. Invest Ophthalmol Vis Sci 2021;62(14):25.Abstract
Purpose: We reported that oxytocin (OXT), added to freshly prepared lacrimal gland lobules, induced myoepithelial cell (MEC) contraction. In other systems, OXT activates phospholipase C (PLC) generating Inositol 1,4,5-trisphosphate (IP3) which increases intracellular calcium concentration ([Ca2+]i) causing contraction. The aim of the current study was to investigate the role of this pathway in OXT-induced contraction of MEC. Methods: Tear volume was measured using the cotton thread method. Lacrimal gland MEC were isolated and propagated from α-smooth muscle actin (SMA)-green fluorescent protein (GFP) mice, in which MEC express GFP making them easily identifiable. RNA and protein samples were prepared for RT-PCR and Western blotting for G protein expression. Changes in [Ca2+]i were measured in Fura-2 loaded MEC using a ratio imaging system. MEC contraction was monitored in real time and changes in cell size were quantified using ImageJ software. Results: OXT applied either topically to surgically exposed lacrimal glands or delivered subcutaneously resulted in increased tear volume. OXT stimulated lacrimal gland MEC contraction in a dose-dependent manner, with a maximum response at 10-7 M. MEC express the PLC coupling G proteins, Gαq and Gα11, and their activation by OXT resulted in a concentration-dependent increase in [Ca2+]i with a maximum response at 10-6 M. Furthermore, the activation of the IP3 receptor to increase [Ca2+]i is crucial for OXT-induced MEC contraction since blocking the IP3 receptor with 2-APB completely abrogated this response. Conclusions: We conclude that OXT uses the PLC/Ca2+ pathway to stimulate MEC contraction and increase lacrimal gland secretion.
Fonda SJ, Bursell S-E, Lewis DG, Clary D, Shahon D, Silva PS. Prevalence of Diabetic Eye Diseases in American Indians and Alaska Natives (AI/AN) as Identified by the Indian Health Service's National Teleophthalmology Program Using Ultrawide Field Imaging (UWFI). Ophthalmic Epidemiol 2021;:1-9.Abstract
PURPOSE: Estimates of diabetic eye disease in American Indian and Alaska Natives (AI/AN) vary over time, region, and methods. This article reports recent prevalence of diabetic retinopathy (DR) and diabetic macular edema (DME) in AI/AN served by the Indian Health Services' (IHS) teleophthalmology program, as identified using ultrawide field imaging (UWFI). METHODS: This was a retrospective analysis of 2016-2019 clinical data (n = 53,900). UWF images were acquired by certified imagers using a validated protocol, and graded by licensed, certified optometrists supervised by an ophthalmologist. Graders evaluated the extent/severity of retinal lesions in comparison to standard photographs. DR lesions predominantly in any peripheral field were considered "predominantly peripheral lesions" (PPL). The analyses calculated prevalence of any DR, any DME, DR and DME severity, sight-threatening disease, and PPL. RESULTS: Patients averaged 56 years of age with a 68 mmol/mol A1c and 55% had had diabetes for 5+ years. Prevalence of any DR, any DME, and sight-threatening disease was 28.6%, 3.0%, and 3.0%. In patients with mild nonproliferative DR, PPL was seen in 25.3%. PPL suggested a more severe level of DR in 8.7% of patients. DR increased with age. DME decreased with age. Males and patients in the Nashville IHS area had more diabetic eye disease. CONCLUSION: AI/AN have a high burden of diabetes and its complications. The IHS is resource-constrained, making accurate disease estimates necessary for resource allocation and budget justifications to Congress. These data update the estimates of diabetic eye disease in Indian Country and suggest that UWFI identifies early DR.
Sharifi S, Islam MM, Sharifi H, Islam R, Koza D, Reyes-Ortega F, Alba-Molina D, Nilsson PH, Dohlman CH, Mollnes TE, Chodosh J, Gonzalez-Andrades M. Tuning gelatin-based hydrogel towards bioadhesive ocular tissue engineering applications. Bioact Mater 2021;6(11):3947-3961.Abstract
Gelatin based adhesives have been used in the last decades in different biomedical applications due to the excellent biocompatibility, easy processability, transparency, non-toxicity, and reasonable mechanical properties to mimic the extracellular matrix (ECM). Gelatin adhesives can be easily tuned to gain different viscoelastic and mechanical properties that facilitate its ocular application. We herein grafted glycidyl methacrylate on the gelatin backbone with a simple chemical modification of the precursor, utilizing epoxide ring-opening reactions and visible light-crosslinking. This chemical modification allows the obtaining of an elastic protein-based hydrogel (GELGYM) with excellent biomimetic properties, approaching those of the native tissue. GELGYM can be modulated to be stretched up to 4 times its initial length and withstand high tensile stresses up to 1.95 MPa with compressive strains as high as 80% compared to Gelatin-methacryloyl (GeIMA), the most studied derivative of gelatin used as a bioadhesive. GELGYM is also highly biocompatible and supports cellular adhesion, proliferation, and migration in both 2 and 3-dimensional cell-cultures. These characteristics along with its super adhesion to biological tissues such as cornea, aorta, heart, muscle, kidney, liver, and spleen suggest widespread applications of this hydrogel in many biomedical areas such as transplantation, tissue adhesive, wound dressing, bioprinting, and drug and cell delivery.
Yu Z, Efstathiou NE, Correa VSMC, Chen XH, Ishihara K, Iesato Y, Narimatsu T, Ntentakis D, Chen Y, Vavvas DG. Receptor interacting protein 3 kinase, not 1 kinase, through MLKL-mediated necroptosis is involved in UVA-induced corneal endothelium cell death. Cell Death Discov 2021;7(1):366.Abstract
Ultraviolet (UV) is one of the most energetic radiations in the solar spectrum that can result in various tissue injury disorders. Previous studies demonstrated that UVA, which represents 95% of incident photovoltaic radiation, induces corneal endothelial cells (CECs) death. Programmed cell death (PCD) has been implicated in numerous ophthalmologic diseases. Here, we investigated receptor-interacting protein 3 kinase (RIPK3), a key signaling molecule of PCD, in UVA-induced injury using a short-term corneal endothelium (CE) culture model. UVA irradiation activated RIPK3 and mediated necroptosis both in mouse CE and primary human CECs (pHCECs). UVA irradiation was associated with upregulation of key necroptotic molecules (DAI, TRIF, and MLKL) that lie downstream of RIPK3. Moreover, RIPK3 inhibition or silencing in primary corneal endothelial cells suppresses UVA-induced cell death, along with downregulation of MLKL in pHCECs. In addition, genetic inhibition or knockout of RIPK3 in mice (RIPK3K51A and RIPK3-/- mice) similarly attenuates cell death and the levels of necroptosis in ex vivo UVA irradiation experiments. In conclusion, these results identify RIPK3, not RIPK1, as a critical regulator of UVA-induced cell death in CE and indicate its potential as a future protective target.
Greiner JV, Glonek T. Intracellular ATP Concentration and Implication for Cellular Evolution. Biology (Basel) 2021;10(11)Abstract
Crystalline lens and striated muscle exist at opposite ends of the metabolic spectrum. Lens is a metabolically quiescent tissue, whereas striated muscle is a mechanically dynamic tissue with high-energy requirements, yet both tissues contain millimolar levels of ATP (>2.3 mM), far exceeding their underlying metabolic needs. We explored intracellular concentrations of ATP across multiple cells, tissues, species, and domains to provide context for interpreting lens/striated muscle data. Our database revealed that high intracellular ATP concentrations are ubiquitous across diverse life forms including species existing from the Precambrian Era, suggesting an ancient highly conserved role for ATP, independent of its widely accepted view as primarily "metabolic currency". Our findings reinforce suggestions that the primordial function of ATP was non-metabolic in nature, serving instead to prevent protein aggregation.
Kuang L, Ross AE, Kanu LN, Romanowski EG, Kowalski RP, Kohane DS, Ciolino JB. A novel, sensitive, and widely accessible besifloxacin quantification method by HPLC-fluorescence: Application to an ocular pharmacokinetic study. J Chromatogr B Analyt Technol Biomed Life Sci 2021;1185:123010.Abstract
Besifloxacin has been embraced for the treatment of ocular bacterial infections. While LC-MS/MS has been used in investigating BSF pharmacokinetics, those costly instruments are not universally available and have complicated requirements for operation and maintenance. Additionally, pharmacokinetics of besifloxacin in dose-intense regimens are still unknown. Herein, a new quantification method was developed employing the widely accessible HPLC with fluorescence detection and applied to an ocular pharmacokinetic study with an intense regimen. Biosamples were pre-treated using protein precipitation. Chromatographic separation was achieved on a C18 column using mobile phase of 0.1% trifluoroacetic acid and acetonitrile. To address the weak fluorescence issue of besifloxacin, effects of detection parameters, elution pattern, pH of mobile phase, and reconstitution solvents were investigated. The method was fully validated per US-FDA guidelines and demonstrated precision (<13%), accuracy (91-112%), lower limit of quantification (5 ng/mL), linearity over clinically relevant concentrations (R2 > 0.999), matrix-effects (93-105%), recoveries (95-106%), and excellent selectivity. The method showed agreement with agar disk diffusion assays for in vitro screening and comparable in vivo performance to LC-MS/MS (Deming Regression, y = 1.010x + 0.123, r = 0.997; Bland-Altman analysis, mean difference was -6.3%; n = 21). Pharmacokinetic parameters suggested superior surface-retentive properties of besifloxacin. Maximum concentrations were 1412 ± 1910 and 0.15 ± 0.12 μg/mL; area under the curve was 1,637 and 1.08 µg·h/g; and half-life was 4.9 and 4.1 h; and pharmacokinetic-to-pharmacodynamic ratios were ≥ 409 and ≤ 17.8 against ocular pathogens in tears and aqueous humor, respectively. This readily available method is sensitive for biosamples and practical for routine use, facilitating besifloxacin therapy development.

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