De novo biosynthesis of anthocyanins in Saccharomyces cerevisiae using metabolic pathway synthases from blueberry.

BACKGROUND: Anthocyanins are water-soluble flavonoids in plants, which give plants bright colors and are widely used as food coloring agents, nutrients, and cosmetic additives. There are several limitations for traditional techniques of collecting anthocyanins from plant tissues, including species, origin, season, and technology. The benefits of using engineering microbial production of natural products include ease of use, controllability, and high efficiency. RESULTS: In this study, ten genes encoding enzymes involved in the anthocyanin biosynthetic pathway were successfully cloned from anthocyanin-rich plant materials blueberry fruit and purple round eggplant rind. The Yeast Fab Assembly technology was utilized to construct the transcriptional units of these genes under different promoters. The transcriptional units of PAL and C4H, 4CL and CHS were fused and inserted into Chr. XVI and IV of yeast strain JDY52 respectively using homologous recombination to gain Strain A. The fragments containing the transcriptional units of CHI and F3H, F3'H and DFR were inserted into Chr. III and XVI to gain Strain B1. Strain B2 has the transcriptional units of ANS and 3GT in Chr. IV. Several anthocyanidins, including cyanidin, peonidin, pelargonidin, petunidin, and malvidin, were detected by LC-MS/MS following the predicted outcomes of the de novo biosynthesis of anthocyanins in S. cerevisiae using a multi-strain co-culture technique. CONCLUSIONS: We propose a novel concept for advancing the heterologous de novo anthocyanin biosynthetic pathway, as well as fundamental information and a theoretical framework for the ensuing optimization of the microbial synthesis of anthocyanins.

Engineered IscB-ωRNA system with expanded target range for base editing.

As the evolutionary ancestor of Cas9 nuclease, IscB proteins serve as compact RNA-guided DNA endonucleases and nickases, making them strong candidates for base editing. Nevertheless, the narrow targeting scope limits the application of IscB systems; thus, it is necessary to find more IscBs that recognize different target-adjacent motifs (TAMs). Here, we identified 10 of 19 uncharacterized IscB proteins from uncultured microbes with activity in mammalian cells. Through protein and ωRNA engineering, we further enhanced the activity of IscB ortholog IscB.m16 and expanded its TAM scope from MRNRAA to NNNGNA, resulting in a variant named IscB.m16*. By fusing the deaminase domains with IscB.m16* nickase, we generated IscB.m16*-derived base editors that exhibited robust base-editing efficiency in mammalian cells and effectively restored Duchenne muscular dystrophy proteins in diseased mice through single adeno-associated virus delivery. Thus, this study establishes a set of compact base-editing tools for basic research and therapeutic applications.

CRISPR-CasRx-mediated disruption of Aqp1/Adrb2/Rock1/Rock2 genes reduces intraocular pressure and retinal ganglion cell damage in mice.

Glaucoma affects approximately 80 million individuals worldwide, a condition for which current treatment options are inadequate. The primary risk factor for glaucoma is elevated intraocular pressure. Intraocular pressure is determined by the balance between the secretion and outflow of aqueous humor. Here we show that using the RNA interference tool CasRx based on shH10 adenovirus-associated virus can reduce the expression of the aqueous humor circulation related genes Rock1 and Rock2, as well as aquaporin 1 and ß2 adrenergic receptor in female mice. This significantly reduced intraocular pressure in female mice and provided protection to the retina ganglion cells, ultimately delaying disease progression. In addition, we elucidated the mechanisms by which the knockdown of Rock1 and Rock2, or aquaporin 1 and ß2 adrenergic receptor in female mice, reduces the intraocular pressure and secures the retina ganglion cells by single-cell sequencing.

Innovative Nanotechnology in Drug Delivery Systems for Advanced Treatment of Posterior Segment Ocular Diseases.

Funduscopic diseases, including diabetic retinopathy (DR) and age-related macular degeneration (AMD), significantly impact global visual health, leading to impaired vision and irreversible blindness. Delivering drugs to the posterior segment of the eye remains a challenge due to the presence of multiple physiological and anatomical barriers. Conventional drug delivery methods often prove ineffective and may cause side effects. Nanomaterials, characterized by their small size, large surface area, tunable properties, and biocompatibility, enhance the permeability, stability, and targeting of drugs. Ocular nanomaterials encompass a wide range, including lipid nanomaterials, polymer nanomaterials, metal nanomaterials, carbon nanomaterials, quantum dot nanomaterials, and so on. These innovative materials, often combined with hydrogels and exosomes, are engineered to address multiple mechanisms, including macrophage polarization, reactive oxygen species (ROS) scavenging, and anti-vascular endothelial growth factor (VEGF). Compared to conventional modalities, nanomedicines achieve regulated and sustained delivery, reduced administration frequency, prolonged drug action, and minimized side effects. This study delves into the obstacles encountered in drug delivery to the posterior segment and highlights the progress facilitated by nanomedicine. Prospectively, these findings pave the way for next-generation ocular drug delivery systems and deeper clinical research, aiming to refine treatments, alleviate the burden on patients, and ultimately improve visual health globally.

METTL1-modulated LSM14A facilitates proliferation and migration in glioblastoma via the stabilization of DDX5.

Glioblastoma (GBM) is characterized by aggressive growth, invasiveness, and poor prognosis. Elucidating the molecular mechanisms underlying GBM is crucial. This study explores the role of Sm-like protein 14 homolog A (LSM14A) in GBM. Bioinformatics and clinical tissue samples analysis demonstrated that overexpression of LSM14A in GBM correlates with poorer prognosis. CCK8, EdU, colony formation, and transwell assays revealed that LSM14A promotes proliferation, migration, and invasion in GBM in vitro. In vivo mouse xenograft models confirmed the results of the in vitro experiments. The mechanism of LSM14A modulating GBM cell proliferation was investigated using mass spectrometry, co-immunoprecipitation (coIP), protein half-life, and methylated RNA immunoprecipitation (MeRIP) analyses. The findings indicate that during the G1/S phase, LSM14A stabilizes DDX5 in the cytoplasm, regulating CDK4 and P21 levels. Furthermore, METTL1 modulates LSM14A expression via mRNA m7G methylation. Altogether, our work highlights the METTL1-LSM14A-DDX5 pathway as a potential therapeutic target in GBM.

Construction of Anthocyanin Biosynthesis System Using Chalcone as a Substrate in Lactococcus lactis NZ9000.

Anthocyanins are high-value natural compounds, but to date, their production still mainly relies on extraction from plants. A five-step metabolic pathway was constructed in probiotic Lactococcus lactis NZ9000 for rapid, stable, and glycosylated anthocyanin biosynthesis using chalcone as a substrate. The genes were cloned from anthocyanin-rich blueberry: chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), anthocyanin synthase (ANS), and UDPG-flavonoid 3-O-glycosyltransferase (3GT). Using HR, the polysaccharide pellicle (PSP) segment of the cell wall polysaccharide synthesis (cwps) gene cluster from L. lactis NZ9000 was cloned into vector p15A-Cm-repDE. Then, CHI and F3H were placed sequentially under the control of NZProm 3 of this gene cluster in the vector, which was transformed into L. lactis NZ9000 to obtain Strain A. Furthermore, Strain B was constructed by placing F3H-DFR-ANS and 3GT under NZProm 2 and 3, respectively. Using LC-MS/MS analysis, several types of anthocyanins, including callistephin chloride, oenin chloride, malvidin O-hexoside, malvidin 3,5-diglucoside, and pelargonidin 3-O-malonyl-malonylhexoside, increased in the supernatant of the co-culture of Strains A and B compared to that of L. lactis NZ9000. This is the first time that a five-step metabolic pathway has been developed for anthocyanin biosynthesis in probiotic L. lactis NZ9000. This work lays the groundwork for novel anthocyanin production by a process involving the placement of several biosynthesis genes under the control of a gene cluster.

Development of graphitic carbon nitride quantum dots-based oxygen self-sufficient platforms for enhanced corneal crosslinking.

Keratoconus, a disorder characterized by corneal thinning and weakening, results in vision loss. Corneal crosslinking (CXL) can halt the progression of keratoconus. The development of accelerated corneal crosslinking (A-CXL) protocols to shorten the treatment time has been hampered by the rapid depletion of stromal oxygen when higher UVA intensities are used, resulting in a reduced cross-linking effect. It is therefore imperative to develop better methods to increase the oxygen concentration within the corneal stroma during the A-CXL process. Photocatalytic oxygen-generating nanomaterials are promising candidates to solve the hypoxia problem during A-CXL. Biocompatible graphitic carbon nitride (g-C3N4) quantum dots (QDs)-based oxygen self-sufficient platforms including g-C3N4 QDs and riboflavin/g-C3N4 QDs composites (RF@g-C3N4 QDs) have been developed in this study. Both display excellent photocatalytic oxygen generation ability, high reactive oxygen species (ROS) yield, and excellent biosafety. More importantly, the A-CXL effect of the g-C3N4 QDs or RF@g-C3N4 QDs composite on male New Zealand white rabbits is better than that of the riboflavin 5'-phosphate sodium (RF) A-CXL protocol under the same conditions, indicating excellent strengthening of the cornea after A-CXL treatments. These lead us to suggest the potential application of g-C3N4 QDs in A-CXL for corneal ectasias and other corneal diseases.

Comprehensive appraisal of lung function in young COPD patients: a single center observational study.

PURPOSE: The present study aimed to investigate the clinical characteristics and lung function impairment in young people diagnosed with chronic obstructive pulmonary disease (COPD). PATIENTS AND METHODS: We retrospectively enrolled patients with COPD who underwent symptom assessment and comprehensive pulmonary function tests at the First Affiliated Hospital of Guangzhou Medical University between August 2017 and March 2022. The patients were categorized into two groups based on age: a young COPD group (aged 20-50 years) and an old COPD group (aged > 50 years). RESULTS: A total of 1282 patients with COPD were included in the study, with 76 young COPD patients and 1206 old COPD patients. Young COPD patients exhibited a higher likelihood of being asymptomatic, lower rates of smoking, and a lower smoking index compared to old COPD patients. Although young COPD patients had higher median post-bronchodilator forced expiratory volume in 1 s (post-BD FEV1) (1.4 vs.1.2 L, P = 0.019), diffusing capacity of the lung for carbon monoxide (DLCO) (7.2 vs. 4.6, P<0.001), and a lower median residual volume to total lung capacity ratio (RV/TLC) compared to their older counterparts, there were no differences observed in severity distribution by GOLD categories or the proportion of lung hyperinflation (RV/TLC%pred > 120%) between two groups. Surprisingly, the prevalence of reduced DLCO was found to be 71.1% in young COPD, although lower than in old COPD (85.2%). CONCLUSION: Young COPD showed fewer respiratory symptoms, yet displayed a similar severity distribution by GOLD categories. Furthermore, a majority of them demonstrated lung hyperinflation and reduced DLCO. These results underscore the importance of a comprehensive assessment of lung function in young COPD patients.

Nano-enabled regulation of DNA damage in tumor cells to enhance neoantigen-based pancreatic cancer immunotherapy.

Low-expression antigens, especially neoantigens, pose a significant challenge in immunotherapy for low immunogenicity pancreatic cancer. Increasing the tumor mutation burden is crucial to enhance the expression of tumor antigens and improve tumor immunogenicity. However, the incomplete intervention in DNA stability hampers effective elevation of the tumor mutation burden, thus reducing the probability of neoantigen. To address this issue, we have developed a novel nano-regulator that intervenes in the DNA stability of tumor cells, thereby enhancing tumor mutations. This nano-regulator comprises metal-organic frameworks (MOFs) encapsulating DNA damage agent doxorubicin and DNA damage repair inhibitor siRNA-ATR, enabling simultaneous induction of DNA mutations and inhibition of their repair. Importantly, this regulator, named as MOFDOX&siATR, can modulate the tumor gene expression profile, induce the production of neoantigens of Atp8b1, and enhance the immunogenicity of pancreatic cancer. The characteristics of DNA stability intervention by MOFDOX&siATR hold promise for augmenting the immune response in low immunogenic tumors, making it a potential nanomedicine for the treatment of pancreatic cancer.

Biointerface-Engineered Hybrid Nanovesicles for Targeted Reprogramming of Tumor Microenvironment.

The tumor microenvironment (TME) of typical tumor types such as triple-negative breast cancer is featured by hypoxia and immunosuppression with abundant tumor-associated macrophages (TAMs), which also emerge as potential therapeutic targets for antitumor therapy. M1-like macrophage-derived exosomes (M1-Exos) have emerged as a promising tumor therapeutic candidate for their tumor-targeting and macrophage-polarization capabilities. However, the limited drug-loading efficiency and stability of M1-Exos have hindered their effectiveness in antitumor applications. Here, a hybrid nanovesicle is developed by integrating M1-Exos with AS1411 aptamer-conjugated liposomes (AApt-Lips), termed M1E/AALs. The obtained M1E/AALs are loaded with perfluorotributylamine (PFTBA) and IR780, as P-I, to construct P-I@M1E/AALs for reprogramming TME by alleviating tumor hypoxia and engineering TAMs. P-I@M1E/AAL-mediated tumor therapy enhances the in situ generation of reactive oxygen species, repolarizes TAMs toward an antitumor phenotype, and promotes the infiltration of T lymphocytes. The synergistic antitumor therapy based on P-I@M1E/AALs significantly suppresses tumor growth and prolongs the survival of 4T1-tumor-bearing mice. By integrating multiple treatment modalities, P-I@M1E/AAL nanoplatform demonstrates a promising therapeutic approach for overcoming hypoxic and immunosuppressive TME by targeted TAM reprogramming and enhanced tumor photodynamic immunotherapy. This study highlights an innovative TAM-engineering hybrid nanovesicle platform for the treatment of tumors characterized by hypoxic and immunosuppressive TME.

Assessing the effectiveness of inhalation therapy in patients with chronic airway diseases: A new digital measurement.

BACKGROUND: This study aimed to evaluate the effectiveness of inhalation therapy in patients with chronic airway diseases via the use of a new multiparametric inhalation assessment device. METHODS: A multiparametric inhalation evaluation device (PF810, UBREATH, Zhejiang, China) that could simulate common inhalation devices with 6 different levels (0-V) of resistance was used in this study. The device was considered suitable if the three parameters of peak inspiratory flow rate (PIFR), effective inspiratory time (EIT), and breath-hold time (BHT) after inspiration met the minimum requirements. RESULTS: A total of 4,559 tests were performed. The qualification rates of 0-V resistance gear from low to high were 3.38 % (I), 8.42 % (0), 15.31 % (II), 16.71 % (III), 20.27 % (IV), and 46.91 % (V). The COPD patients in the 3 experimental groups had the lowest percentages of isolates classified as resistant 0, III, and V, which were 5.65 %, 11.93 %, and 40.43 %, respectively. The lowest percentage was 39.67 % (V) for insufficient EIT and 18.40 % (V) for BHT less than 5 s after inspiration. The results of 149 subjects who had used the inhalation device showed that the VIE and EIT at 0 levels were significantly greater than those before training (Z= -5.651, -5.646, P < 0.001). The VIE and EIT at I-III and V significantly increased after training (all P < 0.05). CONCLUSIONS: Patients using portable inhaler devices do not always inhale with adequate flow patterns. The multiparametric inhalation assessment device may be useful in outpatient settings.

Recent advances in corneal neovascularization imaging.

Corneal neovascularization (CoNV) is a vision-threatening ocular disease commonly secondary to infectious, inflammatory, and traumatic etiologies. Slit lamp photography, in vivo confocal microscopy, angiography, and optical coherence tomography angiography (OCTA) are the primary diagnostic tools utilized in clinical practice to evaluate the vasculature of the ocular surface. However, there is currently a dearth of comprehensive literature that reviews the advancements in imaging technology for CoNV administration. Initially designed for retinal vascular imaging, OCTA has now been expanded to the anterior segment and has shown promising potential for imaging the conjunctiva, cornea, and iris. This expansion allows for the quantitative monitoring of the structural and functional changes associated with CoNV. In this review, we emphasize the impact of algorithm optimization in anterior segment-optical coherence tomography angiography (AS-OCTA) on the diagnostic efficacy of CoNV. Through the analysis of existing literature, animal model assessments are further reported to investigate its pathological mechanism and exhibit remarkable therapeutic interventions. In conclusion, AS-OCTA holds broad prospects and extensive potential for clinical diagnostics and research applications in CoNV.

Prevalence, Medicaid use and mortality risk of low FEV1 in adults aged 20-35 years old in the USA: evidence from a population-based retrospective cohort study.

BACKGROUND: The prevalence, Medicaid use and mortality risk associated with low forced expiratory volume in 1 s (FEV1) among young adults aged 20-35 years are not well understood, despite its potential implications for the development of chronic pulmonary disease and overall prognosis. METHODS: A retrospective cohort study was conducted among young adults aged 20-35 years old, using data from the National Health and Nutrition Examination Survey, National Death Index and Centers for Medicare & Medicaid Services. Participants were categorised into a low FEV1 group (pre-bronchodilator FEV1%pred <80%) and a normal FEV1 group (FEV1%pred ≥80%). Weighted logistic regression analysis was employed to identify the risk factors associated with low FEV1, while Cox proportional hazard models were used to calculate the hazard ratio (HR) for Medicaid use and the all-cause mortality between the two groups. RESULTS: A total of 5346 participants aged 20-35 were included in the study, with 329 in the low FEV1 group and 5017 in the normal group. The weighted prevalence of low FEV1 among young adults was 7.1% (95% CI 6.0 to 8.2). Low body mass index (OR=3.06, 95% CI 1.79 to 5.24), doctor-diagnosed asthma (OR=2.25, 1.28 to 3.93), and wheezing or whistling (OR=1.57, 1.06 to 2.33) were identified as independent risk factors for low FEV1. Over a 15-year follow-up, individuals in the low FEV1 group exhibited a higher likelihood of Medicaid use compared with those in the normal group (HR=1.73, 1.07 to 2.79). However, there was no statistically significant increase in the risk of all-cause mortality over a 30-year follow-up period (HR=1.48, 1.00 to 2.19). CONCLUSIONS: A considerable portion of young adults demonstrated low FEV1 levels, a characteristic that was associated with a higher risk of Medicaid use over a long-term follow-up, yet not linked to an augmented risk of all-cause mortality.

Enantioselective synthesis of chiral α,α-dialkyl indoles and related azoles by cobalt-catalyzed hydroalkylation and regioselectivity switch.

General, catalytic and enantioselective construction of chiral α,α-dialkyl indoles represents an important yet challenging objective to be developed. Herein we describe a cobalt catalyzed enantioselective anti-Markovnikov alkene hydroalkylation via the remote stereocontrol for the synthesis of α,α-dialkyl indoles and other N-heterocycles. This asymmetric C(sp3)-C(sp3) coupling features high flexibility in introducing a diverse set of alkyl groups at the α-position of chiral N-heterocycles. The utility of this methodology has been demonstrated by late-stage functionalization of drug molecules, asymmetric synthesis of bioactive molecules, natural products and functional materials, and identification of a class of molecules exhibiting anti-apoptosis activities in UVB-irradiated HaCaT cells. Ligands play a vital role in controlling the reaction regioselectivity. Changing the ligand from bi-dentate L6 to tridentate L12 enables CoH-catalyzed Markovnikov hydroalkylation. Mechanistic studies disclose that the anti-Markovnikov hydroalkylation involves a migratory insertion process while the Markovnikov hydroalkylation involves a MHAT process.

Evaluation of the Agreement Between a New Pyramid Wavefront Sensor Aberrometer and Scheiner-Smirnov Aberrometers.

PURPOSE: To assess agreement between a new aberrometer (Osiris-T; CSO) employing pyramid wavefront sensor technique and Scheiner-Smirnov aberrometer (OPD-Scan III; Nidek) on measuring ocular, corneal, and internal aberrations in healthy participants. METHODS: The measurements were conducted three times consecutively by an experienced examiner. The total root mean square (RMS) aberrations, higher order aberration RMS, coma Z3±1, trefoil Z3±3, spherical aberration Z40, and astigmatism II Z4±2 up to 7th order were exported in both 4-and 6-mm pupil zones. The parameters between the two devices were statistically compared using the paired t-test, and the differences assessed with Bland-Altman plots and 95% limits of agreement. RESULTS: This prospective study included 70 right eyes of 70 healthy participants with an average age of 25.94 ± 6.59 years (range: 18 to 47 years). The mean difference in the two devices ranged from 0.01 µm for astigmatism II Z4±2 to 0.63 µm for total RMS in 4 mm and from 0.01 to 1.41 µm in 6-mm pupil size. The Bland-Altman analysis of ocular, corneal, and internal aberrations indicated high agreement between the two devices and the maximum absolute values for 95% limits of agreement ranged from 0.03 to 1.06 µm for 4-mm pupil diameters and 0.12 to 1.13 µm for 6-mm pupil diameters. CONCLUSIONS: The newly developed pyramid wavefront sensor technique aberrometer demonstrated a high agreement with a Scheiner-Smirnov aberrometer when measuring ocular, corneal, and internal aberrations in healthy participants. Thus, the two aberrometers may be considered interchangeable for clinical applications. [J Refract Surg. 2024;40(4):e218-e228.].

Rapid Rescue of Goose Astrovirus Genome via Red/ET Assembly.

The host-specific infection of Avian Astrovirus (AAstVs) has posed significant challenges to the poultry industry, resulting in substantial economic losses. However, few reports exist on the functional consequences of genome diversity, cross-species infectivity and mechanisms governing virus replication of AAstVs, making it difficult to develop measures to control astrovirus transmission. Reverse genetics technique can be used to study the function of viruses at the molecular level, as well as investigating pathogenic mechanisms and guide vaccine development and disease treatment. Herein, the reverse genetics technique of goose astrovirus GAstV/JS2019 strain was developed based on use of a reconstructed vector including CMV promotor, hammerhead ribozyme (HamRz), hepatitis delta virus ribozyme (HdvRz), and SV40 tail, then the cloned viral genome fragments were connected using Red/ET recombineering. The recombinant rGAstV-JS2019 was readily rescued by transfected the infectious clone plasmid into LMH cells. Importantly, the rescued rGAstV/JS2019 exhibited similar growth kinetics comparable to those of the parental GAstV/JS2019 isolate in cultured cells. Our research results provide an alternative and more effective reverse genetic tool for a detailed understanding of viral replication, pathogenic mechanisms, and molecular mechanisms of evolution.

Genome Editing VEGFA Prevents Corneal Neovascularization In Vivo.

Corneal neovascularization (CNV) is a common clinical finding seen in a range of eye diseases. Current therapeutic approaches to treat corneal angiogenesis, in which vascular endothelial growth factor (VEGF) A plays a central role, can cause a variety of adverse side effects. The technology of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 can edit VEGFA gene to suppress its expression. CRISPR offers a novel opportunity to treat CNV. This study shows that depletion of VEGFA with a novel CRISPR/Cas9 system inhibits proliferation, migration, and tube formation of human umbilical vein endothelial cells (HUVECs) in vitro. Importantly, subconjunctival injection of this dual AAV-SpCas9/sgRNA-VEGFA system is demonstrated which blocks suture-induced expression of VEGFA, CD31, and α-smooth muscle actin as well as corneal neovascularization in mice. This study has established a strong foundation for the treatment of corneal neovascularization via a gene editing approach for the first time.

Combining small airway parameters with conventional parameters obtained during spirometry to diagnose airflow obstruction: A cross-sectional study.

BACKGROUND AND OBJECTIVE: The use of small airway parameters generated by spirometry, namely forced expiratory flow between 25% and 75% of forced vital capacity (FVC) (FEF25%-75%) and forced expiratory flow at 50% and 75% of FVC (FEF50% and FEF75%, respectively), is widely discussed. We evaluated the importance of these spirometric parameters in a large Chinese population. METHODS: We conducted a cross-sectional observational study in which spirometry and bronchodilator responsiveness (BDR) data were collected in a healthcare centre from May 2021 to August 2022 and in a tertiary hospital from January 2017 to March 2022. Discordance was assessed between the classification of test results by the large airway parameters of forced expiratory volume in 1 second (FEV1) and FEV1/FVC ratio and by the small airway parameters of FEF25%-75%, FEF75% and FEF50%. The predictive power of Z-scores of spirometric parameters for airflow limitation and BDR was assessed using receiver operating characteristic curves. RESULTS: Our study included 26,658 people. Among people with a normal FVC (n = 14,688), 3.7%, 4.5% and 3.6% of cases exhibited normal FEV1/FVC ratio but impaired FEF25%-75%, FEF75% and FEF50%, respectively, while 6.8%-7.0% of people exhibited normal FEV1 but impaired FEF25%-75%, FEF75% and FEF50%. Using the Z-scores of combining both large and small airway parameters in spirometry showed the best area under the curve for predicting airflow limitation (0.90; 95% CI 0.87-0.94) and predicting BDR (0.72; 95% CI 0.71-0.73). CONCLUSION: It is important to consider both large and small airway parameters in spirometry to avoid missing a diagnosis of airflow obstruction.

Repeatability of Epithelium Thickness Measured by an AS-OCT in Different Grades of Keratoconus and Compared to AS-OCT/Placido Topography.

PURPOSE: To compare agreement of corneal epithelium thickness (ET) between AS-OCT system (RTVue, Optovue) and AS-OCT/Placido topographer (MS-39, CSO) in eyes with different stages of keratoconus (KC), and to assess the repeatability of RTVue AS-OCT. DESIGN: Prospective reliability analysis. METHODS: KC eyes were classified into forme fruste KC (FFKC), mild, moderate, and severe KC. Agreement was evaluated with Bland-Altman plots and 95% limits of agreement (LoA). The repeatability of RTVue was assessed via within-subject standard deviation (Sw), test-retest variability (TRT), coefficient of variation (CoV), and intraclass correlation coefficient (ICC). RESULTS: A total of 119 KC eyes were enrolled, with 21 being FFKC, 26 mild, 39 moderate, and 34 severe. The 95% LoA ranged between -5.9 and 4.8 µm for center epithelium thickness (CET), between -5.7 and 8.2 µm for thinnest epithelium thickness (TET). At 1-mm measuring points, the 95% LoA of superior, inferior, nasal, and temporal were -4.2 to 4.7 µm, -5.2 to 6.0 µm, -7.9 to 10.2 µm, and -11.2 to 6.0 µm. At 3-mm measuring points, the corresponding values were -2.8 to 9.3 µm, -2.0 to 13.0 µm, -4.6 to 9.6 µm, and -6.3 to 9.7 µm, indicating that the 2 instruments were not interchangeable without adjustment. Despite that the repeatability of RTVue measurements in KC patients were acceptable, repeatability decreased gradually with the peripheralization of the measurement points. CONCLUSIONS: The 2 OCT-based devices, RTVue and MS-39, do not provide interchangeable measurements of epithelium thickness in KC patients. Repeatability decreases in cases of more severe KC, emphasizing the importance of grading before clinical examination to avoid diagnostic errors.