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result(s) for
"Utheim, Tor P."
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Whole genome sequencing and characterization of Corynebacterium isolated from the healthy and dry eye ocular surface
by
Naqvi, Maria
,
Charnock, Colin
,
Utheim, Tor P.
in
Anti-Bacterial Agents - pharmacology
,
Antibiotics
,
Bacteria
2024
Background
The purpose of this study was to characterize
Corynebacterium
isolated from the ocular surface of dry eye disease patients and healthy controls. We aimed to investigate the pathogenic potential of these isolates in relation to ocular surface health. To this end, we performed whole genome sequencing in combination with biochemical, enzymatic, and antibiotic susceptibility tests. In addition, we employed deferred growth inhibition assays to examine how
Corynebacterium
isolates may impact the growth of potentially competing microorganisms including the ocular pathogens
Pseudomonas aeruginosa
and
Staphylococcus aureus
, as well as other
Corynebacterium
present on the eye.
Results
The 23 isolates were found to belong to 8 different species of
Corynebacterium
with genomes ranging from 2.12 mega base pairs in a novel
Corynebacterium
sp. to 2.65 mega base pairs in
C. bovis.
Whole genome sequencing revealed the presence of a range of antimicrobial targets present in all isolates. Pangenome analysis showed the presence of 516 core genes and that the pangenome is open. Phenotypic characterization showed variously urease, lipase, mucinase, protease and DNase activity in some isolates. Attention was particularly drawn to a potentially new or novel
Corynebacterium
species which had the smallest genome, and which produced a range of hydrolytic enzymes. Strikingly the isolate inhibited in vitro the growth of a range of possible pathogenic bacteria as well as other
Corynebacterium
isolates. The majority of
Corynebacterium
species included in this study did not seem to possess canonical pathogenic activity.
Conclusions
This study is the first reported genomic and biochemical characterization of ocular
Corynebacterium.
A number of potential virulence factors were identified which may have direct relevance for ocular health and contribute to the finding of our previous report on the ocular microbiome, where it was shown that DNA libraries were often dominated by members of this genus. Particularly interesting in this regard was the observation that some
Corynebacterium
, particularly new or novel
Corynebacterium
sp. can inhibit the growth of other ocular
Corynebacterium
as well as known pathogens of the eye.
Journal Article
TheraPearl Eye Mask and Blephasteam for the treatment of meibomian gland dysfunction: a randomized, comparative clinical trial
by
Lai, Xiaoran
,
Olafsson, Snorri
,
Dartt, Darlene A.
in
692/699/3161/3163
,
692/699/3161/3166
,
Clinical trials
2021
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.
Journal Article
Diagnostic Test Efficacy of Meibomian Gland Morphology and Function
by
Lagali, Neil S.
,
Dartt, Darlene A.
,
Chen, Xiangjun
in
692/1807/1482
,
692/699/3161/3166
,
Adolescent
2019
Meibomian gland dysfunction (MGD) is the leading cause of dry eye and proposed treatments are based on disease severity. Our purpose was to establish reliable morphologic measurements of meibomian glands for evaluating MGD severity. This retrospective, cross-sectional study included 100 MGD patients and 20 controls. The patients were classified into dry eye severity level (DESL) 1–4 based on symptoms and clinical parameters including tear-film breakup time, ocular staining and Schirmer I. The gland loss, length, thickness, density and distortion were analyzed. We compared the morphology between patients and controls; examined their correlations to meibum expressibility, quality, and DESL. Relative to controls, the gland thickness, density and distortion were elevated in patients (p < 0.001 for all tests). The area under the receiver operating characteristic curve was 0.98 (95% confidence interval [CI], 0.96–1.0) for gland loss, and 0.96 (CI 0.91–1.0) for gland distortion, with a cutoff value of six distorted glands yielding a sensitivity of 93% and specificity of 97% for MGD diagnosis. The gland distortion was negatively correlated to the meibum expressibility (r = −0.53; p < 0.001) and DESL (r = −0.22, p = 0.018). In conclusion, evaluation of meibomian gland loss and distortion are valuable complementary clinical parameters to assess MGD status.
Journal Article
Seasonal variations in presenting symptoms and signs of dry eye disease in Norway
by
Chen, Xiangjun
,
Utheim, Tor P.
,
Eidet, Jon Roger
in
692/700
,
692/700/139/1735
,
Air temperature
2022
The study investigated the seasonal variations of presenting symptoms and signs of dry eye disease (DED) in Norway. 652 consecutive DED patients examined between August 2012 and May 2015 in Oslo, Norway, were included. Presenting symptoms and signs were related to the season according to when each patient was examined. Weather report data from the examination day were compared with the presenting symptoms and signs. Oslo's mean seasonal temperatures during spring, summer, fall, and winter were 6.4 °C, 15.6 °C, 9.3 °C, and − 2.1 °C, respectively. Dry eye severity level and self-reported symptoms measured by the Ocular surface disease index questionnaire did not differ between seasons. Schirmer I was lower during summer than in other seasons (P < 0.01). The percentage of patients with a pathological tear meniscus height (< 0.2 mm) was higher during fall (P < 0.01) and lower during winter (P < 0.05) compared to the other seasons. Signs and symptoms of DED generally did not correlate with weather report data, although intraocular pressure was weakly associated with mean daily air temperature (r = − 0.22; P < 0.001). Neither dry eye severity level nor dry eye symptoms differ between seasons in Oslo, Norway. However, some parameters for assessing DED show seasonal variations (Schirmer I and tear meniscus height), which are essential to consider when examining patients with DED.
Journal Article
Simple limbal epithelial transplantation: Current status and future perspectives
by
Tønseth, Kim A.
,
Myklebust Ernø, Inger T.
,
Dartt, Darlene A.
in
Acuity
,
Advantages
,
Amniotic membrane
2020
Damage to limbal stem cells as a result of injury or disease can lead to limbal stem cell deficiency (LSCD). This disease is characterized by decreased vision that is often painful and may progress to blindness. Clinical features include inflammation, neovascularization, and persistent cornea epithelial defects. Successful strategies for treatment involve transplantation of grafts harvested from the limbus of the alternate healthy eye, called conjunctival‐limbal autograft (CLAU) and transplantation of limbal cell sheets cultured from limbal biopsies, termed cultured limbal epithelial transplantation (CLET). In 2012, Sangwan and colleagues presented simple limbal epithelial transplantation (SLET), a novel transplantation technique that combines the benefits of CLAU and CLET and avoids the challenges associated with both. In SLET a small biopsy from the limbus of the healthy eye is divided and distributed over human amniotic membrane, which is placed on the affected cornea. Outgrowth occurs from each small explant and a complete corneal epithelium is typically formed within 2 weeks. Advantages of SLET include reduced risk of iatrogenic LSCD occurring in the healthy cornea at harvest; direct transfer circumventing the need for cell culture; and the opportunity to perform biopsy harvest and transplantation in one operation. Success so far using SLET is comparable with CLAU and CLET. Of note, 336 of 404 (83%) operations using SLET resulted in restoration of the corneal epithelium, whereas visual acuity improved in 258 of the 373 (69%) reported cases. This review summarizes the results of 31 studies published on SLET since 2012. Progress, advantages, challenges, and suggestions for future studies are presented. This review examines work reporting simple limbal epithelial transplantation (SLET), an innovative technique that uses minimal limbal tissue from the healthy eye to regenerate the cornea in the limbal deficient diseased eye. SLET has the advantages of requiring only 2 mm × 2 mm of limbal tissue; harvest and transplantation is achieved in a single operation; and cell culture laboratories are unnecessary.
Journal Article
Coordinated collective migration and asymmetric cell division in confluent human keratinocytes without wounding
2018
Epithelial sheet spreading is a fundamental cellular process that must be coordinated with cell division and differentiation to restore tissue integrity. Here we use consecutive serum deprivation and re-stimulation to reconstruct biphasic collective migration and proliferation in cultured sheets of human keratinocytes. In this system, a burst of long-range coordinated locomotion is rapidly generated throughout the cell sheet in the absence of wound edges. Migrating cohorts reach correlation lengths of several millimeters and display dependencies on epidermal growth factor receptor-mediated signaling, self-propelled polarized migration, and a G
1
/G
0
cell cycle environment. The migration phase is temporally and spatially aligned with polarized cell divisions characterized by pre-mitotic nuclear migration to the cell front and asymmetric partitioning of nuclear promyelocytic leukemia bodies and lysosomes to opposite daughter cells. This study investigates underlying mechanisms contributing to the stark contrast between cells in a static quiescent state compared to the long-range coordinated collective migration seen in contact with blood serum.
Epithelial sheet migration requires polarized and coordinated cell movement. Here, the authors demonstrate serum-activated collective migration followed by polarized asymmetric cell divisions in otherwise quiescent human keratinocyte monolayers in the absence of wound edges.
Journal Article
Sex-based differences in conjunctival goblet cell responses to pro-inflammatory and pro-resolving mediators
by
Fjærvoll, Haakon K.
,
Dartt, Darlene A.
,
Wang, Nicholas H.
in
17β-Estradiol
,
631/80/86/1999
,
692/420/256/2515
2022
Many conjunctival inflammatory diseases differ between the sexes and altered conjunctival goblet cells (CGCs) response is often involved. Inflammation is initiated by the release of pro-inflammatory mediators and terminated by the biosynthesis of specialized pro-resolution mediators (SPMs). Herein, we determined the sex-based difference in the responses of CGCs to inflammatory stimuli or pro-resolving lipid SPMs and their interaction with sex hormones. GCs were cultured from pieces of human conjunctiva in RPMI media. CGCs were transferred 24 h before the start of experiments to phenol red-free and FBS-free media to minimize exogenous hormones. RT-PCR, immunofluorescence microscopy (IF), and Western Blot (WB) were performed to determine the presence of sex hormone receptors. Cellular response to pro-inflammatory stimuli or SPMs was studied by measuring the increase in intracellular [Ca
2+
] ([Ca
2+
]
i
) using fura 2/AM microscopy. Use of RT-PCR demonstrated estrogen receptor (ER) α in 4/5 males and 3/3 females; ERβ in 2/4 males and 2/3 females; and androgen receptors (AR) in 3/3 male and 3/3 female CGCs. Positive immunoreactivity by IF and protein expression by WB was detected using antibodies for the ERα and ERβ in 3/3 males and 3/3 females, while AR were only present in males. Significantly different Ca
2+
responses between sexes were found with carbachol only at 10
–3
M, but not with histamine or leukotriene (LT) B
4
at any concentration used. Incubation with dihydrotestosterone (DHT), estrone (E1), or estradiol (E2) at 10
–7
M for 30 min significantly inhibited the LTB
4
-stimulated [Ca
2+
]
i
increase in male and female CGCs. Incubation with DHT, E1, and E2 overnight significantly inhibited the LTB
4
response in females, while DHT and E2 significantly inhibited the LTB
4
response in males. The SPM lipoxin A
4
(LXA
4
) (10
–9
–10
−8
M), but not the resolvins D1 or D2, induced an [Ca
2+
]
i
increase that was significantly higher in males compared to females. We conclude that male and female CGCs showed differences in the expression of sex hormone receptors. Treatment with sex hormones altered pro-inflammatory mediator LTB
4
-induced response. Males compared to females have a higher response to the ω-6-fatty acid derived SPM LXA
4
, indicating males may terminate inflammation in conjunctival goblet cells faster than females.
Journal Article
Using machine learning model explanations to identify proteins related to severity of meibomian gland dysfunction
2023
Meibomian gland dysfunction is the most common cause of dry eye disease and leads to significantly reduced quality of life and social burdens. Because meibomian gland dysfunction results in impaired function of the tear film lipid layer, studying the expression of tear proteins might increase the understanding of the etiology of the condition. Machine learning is able to detect patterns in complex data. This study applied machine learning to classify levels of meibomian gland dysfunction from tear proteins. The aim was to investigate proteomic changes between groups with different severity levels of meibomian gland dysfunction, as opposed to only separating patients with and without this condition. An established feature importance method was used to identify the most important proteins for the resulting models. Moreover, a new method that can take the uncertainty of the models into account when creating explanations was proposed. By examining the identified proteins, potential biomarkers for meibomian gland dysfunction were discovered. The overall findings are largely confirmatory, indicating that the presented machine learning approaches are promising for detecting clinically relevant proteins. While this study provides valuable insights into proteomic changes associated with varying severity levels of meibomian gland dysfunction, it should be noted that it was conducted without a healthy control group. Future research could benefit from including such a comparison to further validate and extend the findings presented here.
Journal Article
Oral and ocular late effects in head and neck cancer patients treated with radiotherapy
by
Jensen, Janicke Liaaen
,
Herlofson, Bente Brokstad
,
Amdal, Cecilie Delphin
in
692/699/3017
,
692/699/3020
,
692/699/3020/3031
2021
A broader understanding of oral and ocular late effects in head and neck cancer (HNC) patients who underwent intensity-modulated radiotherapy (IMRT) may provide valuable information in follow-up and improve quality of life. Twenty-nine HNC patients treated at least 6 months earlier and 30 age-matched controls were recruited. After completing several questionnaires: Oral Health Impact Profile-14 (OHIP-14), Shortened Xerostomia Inventory (SXI), Ocular Surface Disease Index (OSDI) and McMonnies Dry Eye questionnaire (MDEQ), participants underwent oral and ocular examinations. Oral examination included clinical oral dryness score (CODS) and secretion rates of unstimulated and stimulated saliva (UWS, SWS). Ocular examination included tear film break-up time, Schirmer test and ocular surface staining. The patients had more problems related to dry mouth than controls based on CODS and SXI, and more complaints of dry eye disease based on OSDI and MDEQ. UWS and SWS rates and oral health related quality of life were significantly lower in the patient group. Subjective oral dryness (SXI) correlated significantly with subjective ocular dryness (OSDI and MDEQ). Our study demonstrates that HNC patients treated with IMRT experience late effects in terms of xerostomia and ocular dryness underlining the importance of interdisciplinary approach in the evaluation and follow-up of HNC patients.
Journal Article
The relationship between ocular and oral dryness in a cohort from the 65-year-old population in Norway
by
Jensen, Janicke Liaaen
,
Lai, Xiaoran
,
Chen, Xiangjun
in
692/308/174
,
692/699/3020
,
692/699/3161
2022
In the present study, the relationship between dry eyes and dry mouth was explored in 150 65-year-old subjects randomly selected from the general population in Oslo, Norway. The number of drugs, including xerogenic drugs, and current and previous systemic diseases were recorded. Ocular parameters recorded were the McMonnies Dry Eye Questionnaire, the Ocular Surface Disease Index, the Schirmer I Test, tear film break-up time and ocular surface staining. The oral parameters were xerostomia frequency, Summated Xerostomia Inventory, Clinical Oral Dryness Score, and unstimulated and stimulated whole saliva. The participants with current or previous systemic diseases had significantly more ocular and oral symptoms and significantly more oral clinical findings than the participants without a history of disease. Moreover, correlation and factor analyses demonstrated an association between subjective ocular and oral parameters. A significant correlation between the total number of drugs and the presence of ocular and oral symptoms was also noted. When the participants were categorized based on their ocular symptoms, poorer values were found for the oral parameters among the participants more troubled with dry eyes. The results in the present study call for increased awareness and an interdisciplinary approach in matters related to dry eyes and dry mouth.
Journal Article