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Badian RA, Lagali N. The inferocentral whorl region and its directional patterns in the corneal sub-basal nerve plexus: A review. Exp Eye Res 2024; 244:109926. [PMID: 38754688 DOI: 10.1016/j.exer.2024.109926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 04/03/2024] [Accepted: 05/12/2024] [Indexed: 05/18/2024]
Abstract
There has been a growing application of in vivo confocal microscopy (IVCM) in the examination of corneal microstructure, including different corneal layers and corneal nerve fibers in health and in pathological conditions. Corneal nerves forming the sub-basal nerve plexus (SBNP) beneath the corneal basal epithelial cell layer in particular have been intensively researched in health and disease as a marker for corneal neurophysioanatomical and degenerative changes. One intriguing feature in the SBNP that is found inferior to the corneal apex, is a whorl-like pattern (or vortex) of nerves, which represents an anatomical landmark. Evidence has indicated that the architecture of this 'whorl region' is dynamic, changing with time in healthy individuals but also in disease conditions such as in diabetic neuropathy and keratoconus. This review summarizes the known information regarding the characteristics and significance of the whorl region of nerves in the corneal SBNP, as a potential area of high relevance for future disease monitoring and diagnostics.
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Affiliation(s)
- Reza A Badian
- Department of Medical Biochemistry, Unit of Regenerative Medicine, Oslo University Hospital, Oslo, Norway.
| | - Neil Lagali
- Department of Ophthalmology, Sørlandet Hospital Arendal, Arendal, Norway; Department of Biomedical and Clinical Sciences, Faculty of Medicine, Linköping University, Linköping, Sweden.
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Khanna RK, Catanese S, Blasco H, Pisella PJ, Corcia P. Corneal nerves and amyotrophic lateral sclerosis: an in vivo corneal confocal imaging study. J Neurol 2024; 271:3370-3377. [PMID: 38498118 DOI: 10.1007/s00415-024-12282-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 02/25/2024] [Accepted: 02/26/2024] [Indexed: 03/20/2024]
Abstract
OBJECTIVES Amyotrophic lateral sclerosis (ALS) is a severe motor neuron disorder. Diagnosis is challenging due to its clinical heterogeneity and the absence of definitive diagnostic tools, leading to delays averaging between 9.1 and 27 months. In vivo corneal confocal microscopy, assessing the sub-basal nerve plexus of the cornea, has been proposed as a potential biomarker for ALS. We aimed to determine whether the assessment of corneal nerves using in vivo confocal microscopy can serve as an imaging biomarker for ALS. METHODS A single-centre prospective case-control study was conducted in France from September 2021 to March 2023 including patients with ALS according to the revised EI Escorial criteria. The corneal sub-basal nerve plexus was analysed using in vivo confocal microscopy. An automated algorithm (ACCMetrics) was used to evaluate corneal parameters: nerve fibre density, nerve branch density, nerve fibre length, nerve fibre area, nerve total branch density, nerve fibre width, and nerve fractal dimension. RESULTS Twenty-two patients with ALS and 30 controls were included. No significant differences were found between ALS and control groups for all corneal parameters (p > 0.05). Corneal sensitivity did not differ between groups, and no correlation was identified between corneal nerve parameters and ALS disease duration, severity and rate of progression (p > 0.05). CONCLUSIONS The present study does not support the use of in vivo corneal confocal microscopy as an early diagnostic or prognostic tool for ALS. Further research, especially longitudinal investigations, is needed to understand any potential corneal innervation changes as ALS progresses.
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Affiliation(s)
- Raoul K Khanna
- Department of Ophthalmology, Bretonneau University Hospital of Tours, 2 Boulevard Tonnellé, 37000, Tours, France.
- Université de Tours, INSERM, Imaging Brain & Neuropsychiatry iBraiN U1253, 37032, Tours, France.
| | - Sophie Catanese
- Department of Ophthalmology, Bretonneau University Hospital of Tours, 2 Boulevard Tonnellé, 37000, Tours, France
- Université de Tours, INSERM, Imaging Brain & Neuropsychiatry iBraiN U1253, 37032, Tours, France
| | - Hélène Blasco
- Université de Tours, INSERM, Imaging Brain & Neuropsychiatry iBraiN U1253, 37032, Tours, France
- Biochemistry and Molecular Biology Department, Bretonneau University Hospital of Tours, Tours, France
| | - Pierre-Jean Pisella
- Department of Ophthalmology, Bretonneau University Hospital of Tours, 2 Boulevard Tonnellé, 37000, Tours, France
| | - Philippe Corcia
- Université de Tours, INSERM, Imaging Brain & Neuropsychiatry iBraiN U1253, 37032, Tours, France
- Amyotrophic Lateral Sclerosis Centre, Department of Neurology, Bretonneau University Hospital of Tours, Tours, France
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Mvilongo C, Akono ME, Nkoudou D, Nanfack C, Nomo A, Dim R, Eballé AO. [Clinical profile of corneal sensitivity in diabetic patients: A case-control study]. J Fr Ophtalmol 2024; 47:104212. [PMID: 38788250 DOI: 10.1016/j.jfo.2024.104212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 02/10/2024] [Accepted: 03/26/2024] [Indexed: 05/26/2024]
Abstract
PURPOSE To evaluate the corneal sensitivity of black diabetic patients and identify factors associated with changes in corneal sensitivity. METHODOLOGY We conducted a cross-sectional comparative case-control study at the National Obesity Center of the Yaounde Central Hospital and the Djoungolo District Hospital from March 1 to July 31, 2022. Corneal sensitivity was measured using the Cochet-Bonnet esthesiometer in all diabetic patients over 18 years of age, matched for age and sex to a clinically healthy control population. Data were analyzed using SPSS version 23.0 software. A P-value of less than 5% was considered significant. RESULTS A total of 111 diabetic and 111 non-diabetic patients participated in the study. The mean age was 53.46±12.74 years for diabetics and 52.85±11.77 years for non-diabetics (P=0.901). The mean duration of diabetes was 6.4±5.30 years. Corneal sensitivity in diabetics was lower (44.56±9.59mm) compared to non-diabetics (53.59±6.30mm) with a statistically significant difference (P=0.000). Factors associated with decrease in corneal sensitivity in diabetics were duration of diabetes and poor glycemic control. CONCLUSION Decrease in corneal sensitivity related to diabetes is a complication to be systematically screened for during the ophthalmologic follow-up of diabetic patients.
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Affiliation(s)
- C Mvilongo
- Service d'ophtalmologie, hôpital Central de Yaoundé, Yaoundé, Cameroun; Faculté de médecine de l'université de Yaoundé I, Yaoundé, Cameroun.
| | - M E Akono
- Service d'ophtalmologie, hôpital Central de Yaoundé, Yaoundé, Cameroun; Faculté de médecine de l'université de Yaoundé I, Yaoundé, Cameroun
| | - D Nkoudou
- Faculté de médecine de l'université de Yaoundé I, Yaoundé, Cameroun
| | - C Nanfack
- Faculté de médecine de l'université de Yaoundé I, Yaoundé, Cameroun; Service d'ophtalmologie, hôpital gyneco-obstétrique et pédiatrique de Yaoundé, Yaoundé, Cameroun
| | - A Nomo
- Faculté de médecine de l'université de Yaoundé I, Yaoundé, Cameroun; Service d'ophtalmologie, hôpital gyneco-obstétrique et pédiatrique de Yaoundé, Yaoundé, Cameroun
| | - R Dim
- Faculté de médecine de l'université de Yaoundé I, Yaoundé, Cameroun
| | - A O Eballé
- Faculté de médecine de l'université de Yaoundé I, Yaoundé, Cameroun; Service d'ophtalmologie, hôpital de District de Djoungolo/Olembe, Yaoundé, Cameroun
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Li D, Jin X, Wang C, Zhang N, Jin D, Zhang H. Correlation Between Corneal Whorl-Like Nerve and Retinal Neurodegenerative Changes and Their Association With Microvessel Perfusion in Diabetes. Invest Ophthalmol Vis Sci 2023; 64:44. [PMID: 38019489 PMCID: PMC10691402 DOI: 10.1167/iovs.64.14.44] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 11/07/2023] [Indexed: 11/30/2023] Open
Abstract
Purpose The purpose of this study was to compare the evolution of changes in the corneal nerves, retinal nerves, and cells and blood vessels at a single time point in early diabetic retinopathy (DR). Methods Eighty participants (60 with diabetes and 20 nondiabetic controls) were examined. DR was graded according to the International Classification of Diabetic Retinopathy. Inferior whorl length (IWL), spiral orientation, central nerve fiber length (CNFL), retinal nerve fiber layer (RNFL) thickness, ganglion cell complex (GCC) layer thickness, global loss volume (GLV), focal loss volume (FLV) indices, superficial (sVD), and deep vessel densities (dVD) were examined. Results Compared with those of healthy controls, the IWL, CNFL, and FLV were decreased in the diabetic groups (P < 0.001). The IWL was significantly positively correlated with the RNFL and GCC thicknesses in the diabetic group (r = 0.248, P = 0.006 and r = 0.207, P = 0.023, respectively) and significantly negatively correlated with the FLV (r = -0.535, P < 0.001). The sVD was significantly positively correlated with the RNFL thickness (r = 0.314, P < 0.001) and negatively correlated with the GLV (r = -0.229, P = 0.012). Conclusions Our findings suggest a correlation between corneal whorl-like nerve plexus and retinal nerve changes in the early stages of DR and that the IWL of the cornea may be able to indicate the extent of DR. Retinal nerve changes are associated with retinal microvessel perfusion, and nerve changes may precede vessel lesions.
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Affiliation(s)
- Dongyu Li
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin City, Nangang District, Heilongjiang Province, China
| | - Xin Jin
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin City, Nangang District, Heilongjiang Province, China
| | - Chao Wang
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin City, Nangang District, Heilongjiang Province, China
| | - Nan Zhang
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin City, Nangang District, Heilongjiang Province, China
| | - Di Jin
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin City, Nangang District, Heilongjiang Province, China
| | - Hong Zhang
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin City, Nangang District, Heilongjiang Province, China
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Cosmo E, Midena G, Frizziero L, Bruno M, Cecere M, Midena E. Corneal Confocal Microscopy as a Quantitative Imaging Biomarker of Diabetic Peripheral Neuropathy: A Review. J Clin Med 2022; 11:jcm11175130. [PMID: 36079060 PMCID: PMC9457345 DOI: 10.3390/jcm11175130] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/26/2022] [Accepted: 08/29/2022] [Indexed: 11/16/2022] Open
Abstract
Distal symmetric polyneuropathy (DPN), particularly chronic sensorimotor DPN, represents one of the most frequent complications of diabetes, affecting 50% of diabetic patients and causing an enormous financial burden. Whilst diagnostic methods exist to detect and monitor this condition, they have significant limitations, mainly due to their high subjectivity, invasiveness, and non-repeatability. Corneal confocal microscopy (CCM) is an in vivo, non-invasive, and reproducible diagnostic technique for the study of all corneal layers including the sub-basal nerve plexus, which represents part of the peripheral nervous system. We reviewed the current literature on the use of CCM as an instrument in the assessment of diabetic patients, particularly focusing on its role in the study of sub-basal nerve plexus alterations as a marker of DPN. CCM has been demonstrated to be a valid in vivo tool to detect early sub-basal nerve plexus damage in adult and pediatric diabetic patients, correlating with the severity of DPN. Despite its great potential, CCM has still limited application in daily clinical practice, and more efforts still need to be made to allow the dissemination of this technique among doctors taking care of diabetic patients.
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Affiliation(s)
| | | | - Luisa Frizziero
- Department of Neuroscience-Ophthalmology, University of Padova, 35128 Padova, Italy
| | | | | | - Edoardo Midena
- IRCCS—Fondazione Bietti, 00198 Rome, Italy
- Department of Neuroscience-Ophthalmology, University of Padova, 35128 Padova, Italy
- Correspondence: ; Tel.: +39-049-821-2110
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Newlin Lew K, Arnold T, Cantelmo C, Jacque F, Posada-Quintero H, Luthra P, Chon KH. Diabetes Distal Peripheral Neuropathy: Subtypes and Diagnostic and Screening Technologies. J Diabetes Sci Technol 2022; 16:295-320. [PMID: 34994241 PMCID: PMC8861801 DOI: 10.1177/19322968211035375] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Diabetes distal symmetrical peripheral neuropathy (DSPN) is the most prevalent form of neuropathy in industrialized countries, substantially increasing risk for morbidity and pre-mature mortality. DSPN may manifest with small-fiber disease, large-fiber disease, or a combination of both. This review summarizes: (1) DSPN subtypes (small- and large-fiber disease) with attention to clinical signs and patient symptoms; and (2) technological diagnosis and screening for large- and small-fiber disease with inclusion of a comprehensive literature review of published studies from 2015-present (N = 66). Review findings, informed by the most up-to-date research, advance critical understanding of DSPN large- and small-fiber screening technologies, including those designed for point-of-care use in primary care and endocrinology practices.
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Affiliation(s)
- Kelley Newlin Lew
- School of Nursing, University of
Connecticut (UConn), Storrs, CT, USA
- Kelley Newlin Lew, School of Nursing,
University of Connecticut (UConn), 231 Glenbrook Road, Storrs, CT 06269, USA.
| | - Tracey Arnold
- School of Nursing, University of
Connecticut (UConn), Storrs, CT, USA
| | | | - Francky Jacque
- Hispanic Alliance of Southeastern
Connecticut, New London, CT, USA
| | - Hugo Posada-Quintero
- Biomedical Engineering Department,
University of Connecticut (UConn), Storrs, CT, USA
| | - Pooja Luthra
- Division of Endocrinology and
Metabolism, UConn Health, Farmington, CT, USA
| | - Ki H. Chon
- Biomedical Engineering Department,
University of Connecticut (UConn), Storrs, CT, USA
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Gad H, Petropoulos IN, Khan A, Ponirakis G, MacDonald R, Alam U, Malik RA. Corneal confocal microscopy for the diagnosis of diabetic peripheral neuropathy: A systematic review and meta-analysis. J Diabetes Investig 2022; 13:134-147. [PMID: 34351711 PMCID: PMC8756328 DOI: 10.1111/jdi.13643] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/12/2021] [Accepted: 07/15/2021] [Indexed: 01/01/2023] Open
Abstract
INTRODUCTION Corneal confocal microscopy (CCM) is a rapid non-invasive ophthalmic imaging technique that identifies corneal nerve fiber damage. Small studies suggest that CCM could be used to assess patients with diabetic peripheral neuropathy (DPN). AIM To undertake a systematic review and meta-analysis assessing the diagnostic utility of CCM for sub-clinical DPN (DPN- ) and established DPN (DPN+ ). DATA SOURCES Databases (PubMed, Embase, Central, ProQuest) were searched for studies using CCM in patients with diabetes up to April 2020. STUDY SELECTION Studies were included if they reported on at least one CCM parameter in patients with diabetes. DATA EXTRACTION Corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), corneal nerve fiber length (CNFL), and inferior whorl length (IWL) were compared between patients with diabetes with and without DPN and controls. Meta-analysis was undertaken using RevMan V.5.3. DATA SYNTHESIS Thirty-eight studies including ~4,000 participants were included in this meta-analysis. There were significant reductions in CNFD, CNBD, CNFL, and IWL in DPN- vs controls (P < 0.00001), DPN+ vs controls (P < 0.00001), and DPN+ vs DPN- (P < 0.00001). CONCLUSION This systematic review and meta-analysis shows that CCM detects small nerve fiber loss in subclinical and clinical DPN and concludes that CCM has good diagnostic utility in DPN.
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Affiliation(s)
- Hoda Gad
- Department of MedicineWeill Cornell Medicine‐QatarDohaQatar
| | | | - Adnan Khan
- Department of MedicineWeill Cornell Medicine‐QatarDohaQatar
| | | | | | - Uazman Alam
- Diabetes and Neuropathy ResearchDepartment of Eye and Vision Sciences and Pain Research InstituteInstitute of Ageing and Chronic DiseaseUniversity of Liverpool and Aintree University Hospital NHS Foundation TrustLiverpoolUK
- Department of Diabetes and EndocrinologyRoyal Liverpool and Broadgreen University NHS Hospital TrustLiverpoolUK
- Division of Endocrinology, Diabetes and GastroenterologyUniversity of ManchesterManchesterUK
| | - Rayaz A Malik
- Department of MedicineWeill Cornell Medicine‐QatarDohaQatar
- Institute of Cardiovascular MedicineUniversity of ManchesterManchesterUK
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Wide-field mosaics of the corneal subbasal nerve plexus in Parkinson's disease using in vivo confocal microscopy. Sci Data 2021; 8:306. [PMID: 34836991 PMCID: PMC8626466 DOI: 10.1038/s41597-021-01087-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 10/28/2021] [Indexed: 11/09/2022] Open
Abstract
In vivo confocal microscopy (IVCM) is a non-invasive imaging technique facilitating real-time acquisition of images from the live cornea and its layers with high resolution (1-2 µm) and high magnification (600 to 800-fold). IVCM is extensively used to examine the cornea at a cellular level, including the subbasal nerve plexus (SBNP). IVCM of the cornea has thus gained intense interest for probing ophthalmic and systemic diseases affecting peripheral nerves. One of the main drawbacks, however, is the small field of view of IVCM, preventing an overview of SBNP architecture and necessitating subjective image sampling of small areas of the SBNP for analysis. Here, we provide a high-quality dataset of the corneal SBNP reconstructed by automated mosaicking, with an average mosaic image size corresponding to 48 individual IVCM fields of view. The mosaic dataset represents a group of 42 individuals with Parkinson's disease (PD) with and without concurrent restless leg syndrome. Additionally, mosaics from a control group (n = 13) without PD are also provided, along with clinical data for all included participants.
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Takhar JS, Joye AS, Lopez SE, Marneris AG, Tsui E, Seitzman GD, Keenan JD, Gonzales JA. Validation of a Novel Confocal Microscopy Imaging Protocol With Assessment of Reproducibility and Comparison of Nerve Metrics in Dry Eye Disease Compared With Controls. Cornea 2021; 40:603-612. [PMID: 33038151 PMCID: PMC9830965 DOI: 10.1097/ico.0000000000002549] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/15/2020] [Indexed: 01/12/2023]
Abstract
PURPOSE The purposes of this study were to assess the reproducibility of a novel standardized technique for capturing corneal subbasal nerve plexus images with in vivo corneal confocal microscopy and to compare nerve metrics captured with this method in participants with dry eye and control participants. METHODS Cases and controls were recruited based on their International Statistical Classification of Diseases and Related Health Problems (ICD-10) diagnoses. Participants completed the following 3 ocular symptom questionnaires: the Ocular Surface Disease Index, Neuropathic Pain Symptom Inventory, and Dry Eye Questionnaire 5. A novel eye fixation-grid system was used to capture 30 standardized confocal microscopy images of the central cornea. Each participant was imaged twice by different operators. Seven quantitative nerve metrics were analyzed using automated software (ACCmetrics, Manchester, United Kingdom) for all 30 images and a 6-image subset. RESULTS Forty-seven participants were recruited (25 classified as dry eye and 22 controls). The most reproducible nerve metrics were corneal nerve fiber length [intraclass correlation (ICC) = 0.86], corneal nerve fiber area (ICC = 0.86), and fractal dimension (ICC = 0.90). Although differences were not statistically significant, all mean nerve metrics were lower in those with dry eye compared with controls. Questionnaire scores did not significantly correlate with nerve metrics. Reproducibility of nerve metrics was similar when comparing the entire 30-image montage to a central 6-image subset. CONCLUSIONS A standardized confocal imaging technique coupled with quantitative assessment of corneal nerves produced reproducible corneal nerve metrics even with different operators. No statistically significant differences in in vivo corneal confocal microscopy nerve metrics were observed between participants with dry eye and control participants.
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Affiliation(s)
- Jaskirat S. Takhar
- Francis I. Proctor Foundation, University of California, San Francisco, CA
- John A. Burns School of Medicine, University of Hawaii, Honolulu, HI
| | - Ashlin S. Joye
- Francis I. Proctor Foundation, University of California, San Francisco, CA
- Touro University College of Osteopathic Medicine, Vallejo, CA
| | - Sarah E. Lopez
- Francis I. Proctor Foundation, University of California, San Francisco, CA
- Department of Ophthalmology, University of California, San Francisco, CA
| | - Athanasios G. Marneris
- Francis I. Proctor Foundation, University of California, San Francisco, CA
- Department of Ophthalmology, University of California, San Francisco, CA
| | - Edmund Tsui
- Francis I. Proctor Foundation, University of California, San Francisco, CA
- Department of Ophthalmology, University of California, San Francisco, CA
| | - Gerami D. Seitzman
- Francis I. Proctor Foundation, University of California, San Francisco, CA
- Department of Ophthalmology, University of California, San Francisco, CA
| | - Jeremy D. Keenan
- Francis I. Proctor Foundation, University of California, San Francisco, CA
- Department of Ophthalmology, University of California, San Francisco, CA
| | - John A. Gonzales
- Francis I. Proctor Foundation, University of California, San Francisco, CA
- Department of Ophthalmology, University of California, San Francisco, CA
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Early Detection of Diabetic Peripheral Neuropathy: A Focus on Small Nerve Fibres. Diagnostics (Basel) 2021; 11:diagnostics11020165. [PMID: 33498918 PMCID: PMC7911433 DOI: 10.3390/diagnostics11020165] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 01/14/2021] [Accepted: 01/20/2021] [Indexed: 02/07/2023] Open
Abstract
Diabetic peripheral neuropathy (DPN) is the most common complication of both type 1 and 2 diabetes. As a result, neuropathic pain, diabetic foot ulcers and lower-limb amputations impact drastically on quality of life, contributing to the individual, societal, financial and healthcare burden of diabetes. DPN is diagnosed at a late, often pre-ulcerative stage due to a lack of early systematic screening and the endorsement of monofilament testing which identifies advanced neuropathy only. Compared to the success of the diabetic eye and kidney screening programmes there is clearly an unmet need for an objective reliable biomarker for the detection of early DPN. This article critically appraises research and clinical methods for the diagnosis or screening of early DPN. In brief, functional measures are subjective and are difficult to implement due to technical complexity. Moreover, skin biopsy is invasive, expensive and lacks diagnostic laboratory capacity. Indeed, point-of-care nerve conduction tests are convenient and easy to implement however questions are raised regarding their suitability for use in screening due to the lack of small nerve fibre evaluation. Corneal confocal microscopy (CCM) is a rapid, non-invasive, and reproducible technique to quantify small nerve fibre damage and repair which can be conducted alongside retinopathy screening. CCM identifies early sub-clinical DPN, predicts the development and allows staging of DPN severity. Automated quantification of CCM with AI has enabled enhanced unbiased quantification of small nerve fibres and potentially early diagnosis of DPN. Improved screening tools will prevent and reduce the burden of foot ulceration and amputations with the primary aim of reducing the prevalence of this common microvascular complication.
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Ferdousi M, Kalteniece A, Azmi S, Petropoulos IN, Worthington A, D'Onofrio L, Dhage S, Ponirakis G, Alam U, Marshall A, Faber CG, Lauria G, Soran H, Malik RA. Corneal confocal microscopy compared with quantitative sensory testing and nerve conduction for diagnosing and stratifying the severity of diabetic peripheral neuropathy. BMJ Open Diabetes Res Care 2020; 8:8/2/e001801. [PMID: 33355206 PMCID: PMC7754626 DOI: 10.1136/bmjdrc-2020-001801] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/28/2020] [Accepted: 11/21/2020] [Indexed: 12/11/2022] Open
Abstract
INTRODUCTION Diabetic neuropathy can be diagnosed and assessed using a number of techniques including corneal confocal microscopy (CCM). RESEARCH DESIGN AND METHODS We have undertaken quantitative sensory testing, nerve conduction studies and CCM in 143 patients with type 1 and type 2 diabetes without neuropathy (n=51), mild neuropathy (n=47) and moderate to severe neuropathy (n=45) and age-matched controls (n=30). RESULTS Vibration perception threshold (p<0.0001), warm perception threshold (WPT) (p<0.001), sural nerve conduction velocity (SNCV) (p<0.001), corneal nerve fiber density (CNFD) (p<0.0001), corneal nerve branch density (CNBD) (p<0.0001), corneal nerve fiber length (CNFL) (p=0.002), inferior whorl length (IWL) (p=0.0001) and average nerve fiber length (ANFL) (p=0.0001) showed a progressive abnormality with increasing severity of diabetic neuropathy. Receiver operating characteristic curve analysis for the diagnosis of diabetic neuropathy showed comparable performance in relation to the area under the curve (AUC) but differing sensitivities and specificities for vibration perception threshold (AUC 0.79, sensitivity 55%, specificity 90%), WPT (AUC 0.67, sensitivity 50%, specificity 76%), cold perception threshold (AUC 0.64, sensitivity 80%, specificity 47%), SNCV (AUC 0.70, sensitivity 76%, specificity 54%), CNFD (AUC 0.71, sensitivity 58%, specificity 83%), CNBD (AUC 0.70, sensitivity 69%, specificity 65%), CNFL (AUC 0.68, sensitivity 64%, specificity 67%), IWL (AUC 0.72, sensitivity 70%, specificity 65%) and ANFL (AUC 0.72, sensitivity 71%, specificity 66%). CONCLUSION This study shows that CCM identifies early and progressive corneal nerve loss at the inferior whorl and central cornea and has comparable utility with quantitative sensory testing and nerve conduction in the diagnosis of diabetic neuropathy.
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Affiliation(s)
- Maryam Ferdousi
- Division of Cardiovascular Sciences, Cardiac Centre, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Alise Kalteniece
- Division of Cardiovascular Sciences, Cardiac Centre, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Shazli Azmi
- Division of Cardiovascular Sciences, Cardiac Centre, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | | | - Anne Worthington
- Division of Cardiovascular Sciences, Cardiac Centre, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Luca D'Onofrio
- Department of Experimental Medicine, University of Rome La Sapienza, Roma, Lazio, Italy
| | - Shaishav Dhage
- Division of Cardiovascular Sciences, Cardiac Centre, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | | | - Uazman Alam
- Division of Cardiovascular Sciences, Cardiac Centre, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Andrew Marshall
- Division of Cardiovascular Sciences, Cardiac Centre, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Catharina G Faber
- Department of Neurology, Maastricht University, Maastricht, Limburg, The Netherlands
| | - Giuseppe Lauria
- Department of Clinical Neurosciences, Università di Milano - Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta, Milan, Italy
| | - Handrean Soran
- Division of Cardiovascular Sciences, Cardiac Centre, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
- University Department of Medicine, Central Manchester University Hospitals NHS Foundation Trust, Manchester, Greater Manchester, UK
| | - Rayaz A Malik
- Division of Cardiovascular Sciences, Cardiac Centre, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
- Research Division, Weill Cornell Medical College in Qatar, Doha, Qatar
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Yu H, Zhao S, Wang X, Han Y, Zhao J. Comparison of parameter agreement for characterization of corneal subbasal nerve plexus in the whorl-like region and central cornea using in vivo confocal microscopy. Int Ophthalmol 2020; 41:559-565. [PMID: 33165745 DOI: 10.1007/s10792-020-01607-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 10/01/2020] [Indexed: 11/29/2022]
Abstract
PURPOSE To compare the reliability of the whorl-like region with that of the central cornea for accurate assessment of corneal subbasal nerve plexus (SNP) by analyzing the parameter variability of these two anatomical regions in repeated measurements. METHODS Participants were scanned in the central cornea and whorl-like region with in vivo confocal microscopy on three occasions by two examiners within a time span of one week. Coefficients of repeatability (CoR), intra-class correlation coefficient (ICC), and Bland-Altman scatter plots with 95% limits of agreement (LOA) in the central cornea and whorl-like region were calculated, respectively, based on the nerve fiber length, then the inter-observer and intra-observer agreement were compared between these two anatomical regions. RESULTS The inter-observer ICC was 0.945, the inter-observer CoR was 0.052, the intra-observer ICC was 0.936, and the inter-observer CoR was 0.046, with narrow 95% LOA within 1 standard deviation in the whorl-like region, whereas the inter-observer ICC was 0.600, the inter-observer CoR was 0.207, the intra-observer ICC was 0.206, and the intra-observer CoR was 0.253, with 95% LOA nearly threefold wider than the standard deviation in the central cornea. CONCLUSIONS Nerve parameter in the whorl-like region showed higher inter-observer and intra-observer agreement than that of the central cornea. The whorl-like region is a more reliable site for accurate assessment of SNP.
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Affiliation(s)
- Hua Yu
- Tianjin Medical University Eye Hospital, Eye Institute and School of Optometry, No. 251 Fukang Road, Xiqing District, Tianjin, 300384, China.,Shanxi Eye Hospital, Taiyuan, China
| | - Shaozhen Zhao
- Tianjin Medical University Eye Hospital, Eye Institute and School of Optometry, No. 251 Fukang Road, Xiqing District, Tianjin, 300384, China.
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13
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Corneal nerves in diabetes-The role of the in vivo corneal confocal microscopy of the subbasal nerve plexus in the assessment of peripheral small fiber neuropathy. Surv Ophthalmol 2020; 66:493-513. [PMID: 32961210 DOI: 10.1016/j.survophthal.2020.09.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 09/10/2020] [Accepted: 09/14/2020] [Indexed: 02/06/2023]
Abstract
The cornea's intense innervation is responsible for corneal trophism and ocular surface hemostasis maintenance. Corneal diabetic neuropathy affects subbasal nerve plexus, with progressive alteration of nerves' morphology and density. The quantitative analysis of nerve fibers can be performed with in vivo corneal confocal microscopy considering the main parameters such as corneal nerve fibers length, corneal nerve fibers density, corneal nerve branching density, tortuosity coefficient, and beadings frequency. As the nerve examination permits the detection of early changes occurring in diabetes, the invivo corneal confocal microscopy becomes, over time, an important tool for diabetic polyneuropathy assessment and follow-up. In this review, we summarize the actual evidence about corneal nerve changes in diabetes and the relationship between the grade of alterations and the duration and severity of the disease. We aim at understanding how diabetes impacts corneal nerves and how it correlates with sensorimotor peripheral polyneuropathy and retinal complications. We also attempt to analyze the safety of the most common surgical procedures such as cataract and refractive surgery in diabetic patients and to highlight the specific risk factors. We believe that information about the corneal nerve fibers' condition obtained from the in vivo subbasal nerve plexus investigation may be crucial in monitoring peripheral small fiber polyneuropathy and that it will help with decision-making in ophthalmic surgery in diabetic patients.
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14
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Hargrave A, Courson JA, Pham V, Landry P, Magadi S, Shankar P, Hanlon S, Das A, Rumbaut RE, Smith CW, Burns AR. Corneal dysfunction precedes the onset of hyperglycemia in a mouse model of diet-induced obesity. PLoS One 2020; 15:e0238750. [PMID: 32886728 PMCID: PMC7473521 DOI: 10.1371/journal.pone.0238750] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 08/21/2020] [Indexed: 01/23/2023] Open
Abstract
PURPOSE The purpose of this study was to use a mouse model of diet-induced obesity to determine if corneal dysfunction begins prior to the onset of sustained hyperglycemia and if the dysfunction is ameliorated by diet reversal. METHODS Six-week-old male C57BL/6 mice were fed a high fat diet (HFD) or a normal diet (ND) for 5-15 weeks. Diet reversal (DiR) mice were fed a HFD for 5 weeks, followed by a ND for 5 or 10 weeks. Corneal sensitivity was determined using aesthesiometry. Corneal cytokine expression was analyzed using a 32-plex Luminex assay. Excised corneas were prepared for immunofluorescence microscopy to evaluate diet-induced changes and wound healing. For wounding studies, mice were fed a HFD or a ND for 10 days prior to receiving a central 2mm corneal abrasion. RESULTS After 10 days of HFD consumption, corneal sensitivity declined. By 10 weeks, expression of corneal inflammatory mediators increased and nerve density declined. While diet reversal restored nerve density and sensitivity, the corneas remained in a heightened inflammatory state. After 10 days on the HFD, corneal circadian rhythms (limbal neutrophil accumulation, epithelial cell division and Rev-erbα expression) were blunted. Similarly, leukocyte recruitment after wounding was dysregulated and accompanied by delays in wound closure and nerve recovery. CONCLUSION In the mouse, obesogenic diet consumption results in corneal dysfunction that precedes the onset of sustained hyperglycemia. Diet reversal only partially ameliorated this dysfunction, suggesting a HFD diet may have a lasting negative impact on corneal health that is resistant to dietary therapeutic intervention.
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Affiliation(s)
- Aubrey Hargrave
- College of Optometry, University of Houston, Houston, Texas, United States of America
| | - Justin A Courson
- College of Optometry, University of Houston, Houston, Texas, United States of America
| | - Vanna Pham
- College of Optometry, University of Houston, Houston, Texas, United States of America
| | - Paul Landry
- College of Optometry, University of Houston, Houston, Texas, United States of America
| | - Sri Magadi
- College of Optometry, University of Houston, Houston, Texas, United States of America
| | - Pooja Shankar
- College of Optometry, University of Houston, Houston, Texas, United States of America
| | - Sam Hanlon
- College of Optometry, University of Houston, Houston, Texas, United States of America
| | - Apoorva Das
- College of Optometry, University of Houston, Houston, Texas, United States of America
| | - Rolando E Rumbaut
- Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas, United States of America
- Center for Translational Research on Inflammatory Diseases (CTRID), Michael E. DeBakey Veterans Affairs Medical Center, Houston, Texas, United States of America
| | - C Wayne Smith
- Center for Translational Research on Inflammatory Diseases (CTRID), Michael E. DeBakey Veterans Affairs Medical Center, Houston, Texas, United States of America
| | - Alan R Burns
- College of Optometry, University of Houston, Houston, Texas, United States of America
- Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas, United States of America
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15
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Ferdousi M, Kalteniece A, Petropoulos I, Azmi S, Dhage S, Marshall A, Boulton AJM, Efron N, Faber CG, Lauria G, Soran H, Malik RA. Diabetic Neuropathy Is Characterized by Progressive Corneal Nerve Fiber Loss in the Central and Inferior Whorl Regions. Invest Ophthalmol Vis Sci 2020; 61:48. [PMID: 32232351 PMCID: PMC7401481 DOI: 10.1167/iovs.61.3.48] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Purpose We hypothesized that longitudinal changes in corneal nerve morphology would differ between the central cornea and inferior whorl in relation to other measures of diabetic neuropathy. Methods Thirty patients with diabetes (age: 54.08 ± 15.86, duration: 23.95 ± 14.2, HbA1c: 7.51 ± 1.37) and 19 age-matched healthy controls (age: 49.47 ± 13.25) underwent assessment of neuropathy disability score (NDS), vibration perception threshold (VPT), cold (CPT) and warm (WPT) perception thresholds, peroneal motor nerve conduction velocity (PMNCV), corneal nerve fiber density (CNFD), branch density (CNBD), fiber length (CNFL), inferior whorl length (IWL), and the average of CNFL and IWL (ANFL) at baseline and after 1 to 8 years. Results In patients with diabetes, between baseline and follow-up, there was a significant reduction in CNBD (57.72 ± 30.08 vs. 44.04 ± 23.69; P = 0.02), CNFL (21.77 ± 5.19 vs. 15.65 ± 4.7; P < 0.0001), IWL (24.69 ± 8.67 vs. 14.23 ± 6.13; P < 0.0001), ANFL (23.26 ± 5.53 vs. 15.09 ± 4.48; P < 0.0001), and WPT (43.56 ± 4.43 vs. 40.78 ± 4.93; P = 0.01), and an increase in VPT (12.9 ± 8.96 vs. 13.78 ± 8.99; P = 0.02). There was no significant change in CNFD (27.12 ± 8.2 vs. 25.43 ± 7.11; P = 0.2), NDS (3.38 ± 3.35 vs. 2.61 ± 2.8; P = 0.08), CPT (17.7 ± 10.59 vs. 22.45 ± 9.23; P = 0.06), or PMNCV (42.4 ± 4.21 vs. 42.16 ± 6.3; P = 0.2). Conclusions There is evidence of corneal nerve loss in patients with diabetes, particularly at the inferior whorl during follow-up.
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16
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Badian RA, Utheim TP, Lagali N. Region of interest and directional analysis of subbasal nerves in wide-area corneal nerve plexus mosaics in type 2 diabetes mellitus. Sci Rep 2020; 10:10802. [PMID: 32612112 PMCID: PMC7329902 DOI: 10.1038/s41598-020-67737-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 06/10/2020] [Indexed: 12/30/2022] Open
Abstract
In vivo confocal microscopy (IVCM) imaging of the corneal subbasal nerve plexus (SBNP) is a clinical imaging modality gaining popularity for the diagnosis and follow-up of corneal neuropathy in various conditions such as diabetes mellitus. There remain, however, major limitations to the method, hindering its widespread clinical use. Finding the same exact area of the central cornea to standardize image acquisition is difficult without a reference point. Alternatively, creating wide-area mosaics of the SBNP is resource-intensive and has not yet been developed for routine clinical use. Here, we investigated whether IVCM analysis of the corneal SBNP in a predetermined, anatomically standardized region of interest (ROI) could be applied as an equivalent substitution for wide-area SBNP mosaic generation and analysis. Furthermore, we investigated nerve patterns outside the central corneal region for a possible relationship to type 2 diabetes mellitus status using a publicly available dataset. We found that corneal nerve fibre length density (CNFL) based on the ROI underestimated the mosaic-based CNFL by an average of 34% in 90% of cases (150 eyes), and did not exhibit a significant reduction with diabetes, as seen in the full SBNP. Outside the central cornea, nerve orientation differed depending on the anatomic region (left, central or right superior plexus, P < 0.001). Moreover, in long-term type 2 diabetes mellitus (≥ 10 years, 28 subjects), nerve density in the left superior sector of the SBNP was decreased (P < 0.001) while that in the central superior SBNP increased (P = 0.01) relative to 35 age-matched healthy subjects with normal glucose tolerance. These results indicate that subbasal nerve degeneration in type 2 diabetes mellitus can vary according to anatomic location, and regions with potential diagnostic value outside the central SBNP may warrant further investigation.
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Affiliation(s)
- Reza A Badian
- Unit of Regenerative Medicine, Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway.
| | - Tor Paaske Utheim
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway.,Department of Ophthalmology, Sørlandet Hospital Arendal, Arendal, Norway
| | - Neil Lagali
- Department of Ophthalmology, Sørlandet Hospital Arendal, Arendal, Norway.,Department of Ophthalmology, Institute for Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
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17
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Tummanapalli SS, Issar T, Kwai N, Pisarcikova J, Poynten AM, Krishnan AV, Willcox MDP, Markoulli M. A Comparative Study on the Diagnostic Utility of Corneal Confocal Microscopy and Tear Neuromediator Levels in Diabetic Peripheral Neuropathy. Curr Eye Res 2019; 45:921-930. [DOI: 10.1080/02713683.2019.1705984] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
| | - Tushar Issar
- Prince of Wales Clinical School, University of New South Wales, Sydney, Australia
| | - Natalie Kwai
- Prince of Wales Clinical School, University of New South Wales, Sydney, Australia
| | - Jana Pisarcikova
- School of Optometry & Vision Science, University of New South Wales, Sydney, Australia
| | - Ann M. Poynten
- Department of Endocrinology, Prince of Wales Hospital, Sydney, Australia
| | - Arun V. Krishnan
- Prince of Wales Clinical School, University of New South Wales, Sydney, Australia
| | - Mark D. P. Willcox
- School of Optometry & Vision Science, University of New South Wales, Sydney, Australia
| | - Maria Markoulli
- School of Optometry & Vision Science, University of New South Wales, Sydney, Australia
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18
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Abstract
PURPOSE The purpose of this study was to establish an age-dependent normative range and factors affecting the migration rate of the corneal subbasal nerve plexus in a healthy control population. METHODS Corneal nerve migration rate was measured in 60 healthy participants grouped by age: A, aged 20 to 39 years (n = 20); B, 40 to 59 years (n = 20); and C, 60 to 79 years (n = 20). Laser-scanning corneal confocal microscopy was performed on the right eye of all participants at baseline and again after 3 weeks. Fully automated software was used to montage the frames. Distinctive nerve landmarks were manually reidentified between the two montages, and a software program was developed to measure the migration of these landmark points to determine corneal nerve migration rate in micrometers per week (μm/wk). RESULTS The mean ± SD age of all participants in the study was 47.5 ± 15.5 years; 62% of participants were male. The average corneal nerve migration rates of groups A, B, and C were 42.0 ± 14.0, 42.3 ± 15.5, and 42.0 ± 10.8 μm/wk, respectively (P = .99). There was no difference in corneal nerve migration rate between male (41.1 ± 13.5 μm/wk) and female (43.7 ± 13.2 μm/wk) participants (P = .47). There was no significant correlation between age (P = .97), smoking (P = .46), alcohol use (P = .61), and body mass index (P = .49, respectively) with corneal nerve migration rate. However, exercise frequency correlated significantly (P = .04) with corneal nerve migration rate. CONCLUSIONS Corneal nerve migration rate varies in healthy individuals and is not affected by age, sex, or body mass index but is related to physical activity.
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19
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Lyu Y, Zeng X, Li F, Zhao S. The effect of the duration of diabetes on dry eye and corneal nerves. Cont Lens Anterior Eye 2019; 42:380-385. [PMID: 31029535 DOI: 10.1016/j.clae.2019.02.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 01/09/2019] [Accepted: 02/19/2019] [Indexed: 01/26/2023]
Abstract
PURPOSE To investigate the relationship between the duration of type 2 diabetes mellitus (DM) and the ocular surface, and to address the question of why some people with lengthy DM duration are asymptomatic, whereas some people with shorter DM duration have pain or discomfort in their eyes. METHODS Eighty-seven eyes of 87 subjects with different durations of DM and 49 eyes of 49 subjects without DM underwent Schirmer I test, tear film break-up time, sodium fluorescein staining and tear meniscus height (TMH) measurement, and completed the Standardized Patient Evaluation of Eye Dryness (SPEED) questionnaire. Corneal structure and function were assessed with in vivo confocal corneal microscopy and with a corneal sensitivity esthesiometer. Both corneal nerve fiber length and inferior whorl length (IWL) were assessed as indices for neural structure. Age and gender were matched between groups. HbA1c levels >7.8% and proliferative diabetic retinopathy were exclusion criteria. RESULTS In the DM group, compared with the non-DM group, the SPEED score was significantly higher (p = 0.013), and corneal sensitivity and IWL were lower (p < 0.001). Schirmer I test, corneal sensitivity and IWL differed significantly between the group with DM duration >10 years and the non-DM (control) group (p = 0.021, p < 0.001, p < 0.001, respectively). Schirmer I test and IWL were significantly lower in the group with DM >10 years than in the group with DM ≤10 years (p = 0.023, p < 0.001, respectively). Corneal sensitivity was positively correlated with IWL regardless of diabetes status. CONCLUSIONS The lower SPEED score and asymptomatic feeling in people with a longer DM duration may be explained by the decreased IWL and reduced sensitivity.
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Affiliation(s)
- Ying Lyu
- Tianjin Medical University Eye Hospital, Tianjin Medical University Eye Institute &School of Optometry and Ophthalmology, Tianjin Medical University, Tianjin, 300384, China.
| | - Xiaoyu Zeng
- Tianjin Medical University Eye Hospital, Tianjin Medical University Eye Institute &School of Optometry and Ophthalmology, Tianjin Medical University, Tianjin, 300384, China.
| | - Fei Li
- Tianjin Medical University Eye Hospital, Tianjin Medical University Eye Institute &School of Optometry and Ophthalmology, Tianjin Medical University, Tianjin, 300384, China.
| | - Shaozhen Zhao
- Tianjin Medical University Eye Hospital, Tianjin Medical University Eye Institute &School of Optometry and Ophthalmology, Tianjin Medical University, Tianjin, 300384, China.
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20
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Implementation of a Quality Index for Improvement of Quantification of Corneal Nerves in Corneal Confocal Microscopy Images: A Multicenter Study. Cornea 2019; 38:921-926. [DOI: 10.1097/ico.0000000000001949] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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21
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Lv Y, Zhao S. What is the best strategy on detection of cornea neuropathy in people with diabetes? Recent advances in potential measurements. Diabetes Res Clin Pract 2018; 142:203-212. [PMID: 29596948 DOI: 10.1016/j.diabres.2018.03.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 02/24/2018] [Accepted: 03/06/2018] [Indexed: 12/15/2022]
Abstract
There are well-acknowledged clinical or pre-clinical measurements concerning diabetic peripheral neuropathy (DPN). The current gold standard for diagnosis of diabetic peripheral neuropathy is nerve conduction suitable for detecting large nerve fiber function and intraepidermal nerve fiber density assessment for small fiber damage evaluation [2]. The lack of a sensitive, non-invasive, and repeatable endpoint to measure changes in small nerve fibers is a major factor holding back clinical trials for the treatment of diabetic peripheral neuropathy. As cornea is the most densely innerved tissue, assessing corneal nerves' structure and function will be promising to predict and assess the degree of DPN. In the diabetic micro-environment, damaged corneal nerves lead to decreased corneal sensitivity, both of which resulting in abnormal tear function. According to this theory, the measurements of nerve structure, corneal sensitivity, tear secretion and tear components, to some extent, can reveal and assess the state of corneal neuropathy. This review focuses on summarizing the knowledge of the latest detective methods of diabetic corneal neuropathy, popular in use or possible to further in study and be applied into clinical practice.
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Affiliation(s)
- Ying Lv
- Tianjin Medical University Eye Hospital, Tianjin Medical University Eye Institute & School of Optometry and Ophthalmology, Tianjin Medical University, Tianjin 300384, China.
| | - Shaozhen Zhao
- Tianjin Medical University Eye Hospital, Tianjin Medical University Eye Institute & School of Optometry and Ophthalmology, Tianjin Medical University, Tianjin 300384, China.
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22
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Bikbova G, Oshitari T, Baba T, Bikbov M, Yamamoto S. Diabetic corneal neuropathy: clinical perspectives. Clin Ophthalmol 2018; 12:981-987. [PMID: 29872257 PMCID: PMC5973365 DOI: 10.2147/opth.s145266] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Diabetic keratopathy is characterized by impaired innervation of the cornea that leads to decreased sensitivity, with resultant difficulties with epithelial wound healing. These difficulties in wound healing put patients at risk for ocular complications such as surface irregularities, corneal infections, and stromal opacification. Pathological changes in corneal innervations in diabetic patients are an important early indicator of diabetic neuropathy. The decrease in corneal sensitivity is strongly correlated with the duration of diabetes as well as the severity of the neuropathy. This review presents recent findings in assessing the ocular surface as well as the recent therapeutic strategies for optimal management of individuals with diabetes who are susceptible to developing diabetic neuropathy.
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Affiliation(s)
- Guzel Bikbova
- Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Chiba, Japan.,Cornea and Refractive Surgery Department, Ufa Eye Research Institute, Ufa, Russia
| | - Toshiyuki Oshitari
- Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Takayuki Baba
- Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Mukharram Bikbov
- Cornea and Refractive Surgery Department, Ufa Eye Research Institute, Ufa, Russia
| | - Shuichi Yamamoto
- Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Chiba, Japan
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Kokot J, Wylęgała A, Wowra B, Wójcik Ł, Dobrowolski D, Wylęgała E. Corneal confocal sub-basal nerve plexus evaluation: a review. Acta Ophthalmol 2018; 96:232-242. [PMID: 28741902 DOI: 10.1111/aos.13518] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 06/01/2017] [Indexed: 12/12/2022]
Abstract
The aim of this study was to review the most recent data about corneal sub-basal nerve plexus (SNP) evaluated with the use of corneal confocal microscopy (CCM). For this purpose, an electronic search was conducted based on PubMed and Google Scholar and Web of Science databases from 2008 up to the end of 2016. Ninety-eight articles in English were cited, as well as abstracts in other languages, concerning the morphology and function of corneal SNP in various diseases. Changes in corneal SNP as a result of local treatment were also introduced. Figures with scans from confocal microscopy from our Department were included. The main conclusion of this review was that both corneal SNP diminishment and high tortuosity as well as low sensitivity are in principle related to the presence or level of pathology. In addition, increased nerve tortuosity may represent a morphological determinant of nerve regeneration. However, the presented literature shows that SNP changes are not characteristic for one unified corneal pathology; rather, they reflect the non-specific pathological process present in many diseases. Future studies should use automatized biometric software and also examine the effects of new treatments on SNP.
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Affiliation(s)
- Joanna Kokot
- Ophthalmology Department; Railway Hospital Katowice; II School of Medicine with the Division of Dentistry in Zabrze; Medical University of Silesia; Katowice Poland
| | - Adam Wylęgała
- Ophthalmology Department; Railway Hospital Katowice; II School of Medicine with the Division of Dentistry in Zabrze; Medical University of Silesia; Katowice Poland
| | - Bogumił Wowra
- Ophthalmology Department; Railway Hospital Katowice; II School of Medicine with the Division of Dentistry in Zabrze; Medical University of Silesia; Katowice Poland
| | - Łukasz Wójcik
- Ophthalmology Department; Railway Hospital Katowice; II School of Medicine with the Division of Dentistry in Zabrze; Medical University of Silesia; Katowice Poland
| | - Dariusz Dobrowolski
- Ophthalmology Department; Railway Hospital Katowice; II School of Medicine with the Division of Dentistry in Zabrze; Medical University of Silesia; Katowice Poland
| | - Edward Wylęgała
- Ophthalmology Department; Railway Hospital Katowice; II School of Medicine with the Division of Dentistry in Zabrze; Medical University of Silesia; Katowice Poland
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Wide-field corneal subbasal nerve plexus mosaics in age-controlled healthy and type 2 diabetes populations. Sci Data 2018; 5:180075. [PMID: 29688226 PMCID: PMC5914299 DOI: 10.1038/sdata.2018.75] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 03/14/2018] [Indexed: 12/12/2022] Open
Abstract
A dense nerve plexus in the clear outer window of the eye, the cornea, can be imaged in vivo to enable non-invasive monitoring of peripheral nerve degeneration in diabetes. However, a limited field of view of corneal nerves, operator-dependent image quality, and subjective image sampling methods have led to difficulty in establishing robust diagnostic measures relating to the progression of diabetes and its complications. Here, we use machine-based algorithms to provide wide-area mosaics of the cornea's subbasal nerve plexus (SBP) also accounting for depth (axial) fluctuation of the plexus. Degradation of the SBP with age has been mitigated as a confounding factor by providing a dataset comprising healthy and type 2 diabetes subjects of the same age. To maximize reuse, the dataset includes bilateral eye data, associated clinical parameters, and machine-generated SBP nerve density values obtained through automatic segmentation and nerve tracing algorithms. The dataset can be used to examine nerve degradation patterns to develop tools to non-invasively monitor diabetes progression while avoiding narrow-field imaging and image selection biases.
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25
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Greater corneal nerve loss at the inferior whorl is related to the presence of diabetic neuropathy and painful diabetic neuropathy. Sci Rep 2018; 8:3283. [PMID: 29459766 PMCID: PMC5818543 DOI: 10.1038/s41598-018-21643-z] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 02/07/2018] [Indexed: 02/06/2023] Open
Abstract
We assessed whether a measure of more distal corneal nerve fibre loss at the inferior whorl(IW) region is better than proximal measures of central corneal nerve damage in relation to the diagnosis of diabetic peripheral neuropathy(DPN), painful DPN and quality of life(QoL). Participants underwent detailed assessment of neuropathy, QoL using the SF36 questionnaire, pain visual analogue score(VAS), and corneal confocal microscopy(CCM). Corneal nerve fibre density (CNFD), branch density (CNBD) and length (CNFL) at the central cornea and inferior whorl length (IWL) and average(ANFL) and total(TNFL) nerve fibre length were compared in patients with and without DPN and between patients with and without painful DPN and in relation to QoL. All CCM parameters were significantly reduced, but IWL was reduced ~three-fold greater than CNFL in patients with and without DPN compared to controls. IWL(p = 0.001), ANFL(p = 0.01) and TNFL(p = 0.02) were significantly lower in patients with painful compared to painless DPN. The VAS score correlated with IWL(r = −0.36, P = 0.004), ANFL(r = −0.32, P = 0.01) and TNFL(r = −0.32, P = 0.01) and QoL correlated with CNFL(r = 0.35, P = 0.01) and IWL(r = 0.4, P = 0.004). Corneal nerve fibre damage is more prominent at the IW, lower in patients with painful compared to painless neuropathy and relates to their QoL. IWL may provide additional clinical utility for CCM in patients with DPN.
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27
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A systematic review on the impact of diabetes mellitus on the ocular surface. Nutr Diabetes 2017; 7:e251. [PMID: 28319106 PMCID: PMC5380897 DOI: 10.1038/nutd.2017.4] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 11/10/2016] [Accepted: 11/14/2016] [Indexed: 12/27/2022] Open
Abstract
Diabetes mellitus is associated with extensive morbidity and mortality in any human community. It is well understood that the burden of diabetes is attributed to chronic progressive damage in major end-organs, but it is underappreciated that the most superficial and transparent organ affected by diabetes is the cornea. Different corneal components (epithelium, nerves, immune cells and endothelium) underpin specific systemic complications of diabetes. Just as diabetic retinopathy is a marker of more generalized microvascular disease, corneal nerve changes can predict peripheral and autonomic neuropathy, providing a window of opportunity for early treatment. In addition, alterations of immune cells in corneas suggest an inflammatory component in diabetic complications. Furthermore, impaired corneal epithelial wound healing may also imply more widespread disease. The non-invasiveness and improvement in imaging technology facilitates the emergence of new screening tools. Systemic control of diabetes can improve ocular surface health, possibly aided by anti-inflammatory and vasoprotective agents.
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Ziegler D, Winter K, Strom A, Zhivov A, Allgeier S, Papanas N, Ziegler I, Brüggemann J, Ringel B, Peschel S, Köhler B, Stachs O, Guthoff RF, Roden M. Spatial analysis improves the detection of early corneal nerve fiber loss in patients with recently diagnosed type 2 diabetes. PLoS One 2017; 12:e0173832. [PMID: 28296936 PMCID: PMC5352008 DOI: 10.1371/journal.pone.0173832] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 02/27/2017] [Indexed: 12/15/2022] Open
Abstract
Corneal confocal microscopy (CCM) has revealed reduced corneal nerve fiber (CNF) length and density (CNFL, CNFD) in patients with diabetes, but the spatial pattern of CNF loss has not been studied. We aimed to determine whether spatial analysis of the distribution of corneal nerve branching points (CNBPs) may contribute to improving the detection of early CNF loss. We hypothesized that early CNF decline follows a clustered rather than random distribution pattern of CNBPs. CCM, nerve conduction studies (NCS), and quantitative sensory testing (QST) were performed in a cross-sectional study including 86 patients recently diagnosed with type 2 diabetes and 47 control subjects. In addition to CNFL, CNFD, and branch density (CNBD), CNBPs were analyzed using spatial point pattern analysis (SPPA) including 10 indices and functional statistics. Compared to controls, patients with diabetes showed lower CNBP density and higher nearest neighbor distances, and all SPPA parameters indicated increased clustering of CNBPs (all P<0.05). SPPA parameters were abnormally increased >97.5th percentile of controls in up to 23.5% of patients. When combining an individual SPPA parameter with CNFL, ≥1 of 2 indices were >99th or <1st percentile of controls in 28.6% of patients compared to 2.1% of controls, while for the conventional CNFL/CNFD/CNBD combination the corresponding rates were 16.3% vs 2.1%. SPPA parameters correlated with CNFL and several NCS and QST indices in the controls (all P<0.001), whereas in patients with diabetes these correlations were markedly weaker or lost. In conclusion, SPPA reveals increased clustering of early CNF loss and substantially improves its detection when combined with a conventional CCM measure in patients with recently diagnosed type 2 diabetes.
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Affiliation(s)
- Dan Ziegler
- Institute for Clinical Diabetology, German Diabetes Center at Heinrich Heine University, Leibniz Center for Diabetes Research, Düsseldorf, Germany
- Department of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
- * E-mail:
| | - Karsten Winter
- Institute of Anatomy, University of Leipzig, Leipzig, Germany
| | - Alexander Strom
- Institute for Clinical Diabetology, German Diabetes Center at Heinrich Heine University, Leibniz Center for Diabetes Research, Düsseldorf, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
| | - Andrey Zhivov
- Department of Ophthalmology, University of Rostock, Rostock, Germany
| | - Stephan Allgeier
- Institute for Applied Computer Science, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Nikolaos Papanas
- Institute for Clinical Diabetology, German Diabetes Center at Heinrich Heine University, Leibniz Center for Diabetes Research, Düsseldorf, Germany
| | - Iris Ziegler
- Institute for Clinical Diabetology, German Diabetes Center at Heinrich Heine University, Leibniz Center for Diabetes Research, Düsseldorf, Germany
| | - Jutta Brüggemann
- Institute for Clinical Diabetology, German Diabetes Center at Heinrich Heine University, Leibniz Center for Diabetes Research, Düsseldorf, Germany
| | - Bernd Ringel
- Institute for Clinical Diabetology, German Diabetes Center at Heinrich Heine University, Leibniz Center for Diabetes Research, Düsseldorf, Germany
| | - Sabine Peschel
- Department of Ophthalmology, University of Rostock, Rostock, Germany
| | - Bernd Köhler
- Institute for Applied Computer Science, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Oliver Stachs
- Department of Ophthalmology, University of Rostock, Rostock, Germany
| | - Rudolf F. Guthoff
- Department of Ophthalmology, University of Rostock, Rostock, Germany
| | - Michael Roden
- Institute for Clinical Diabetology, German Diabetes Center at Heinrich Heine University, Leibniz Center for Diabetes Research, Düsseldorf, Germany
- Department of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
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Cruzat A, Qazi Y, Hamrah P. In Vivo Confocal Microscopy of Corneal Nerves in Health and Disease. Ocul Surf 2017; 15:15-47. [PMID: 27771327 PMCID: PMC5512932 DOI: 10.1016/j.jtos.2016.09.004] [Citation(s) in RCA: 218] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 09/19/2016] [Accepted: 09/25/2016] [Indexed: 12/20/2022]
Abstract
In vivo confocal microscopy (IVCM) is becoming an indispensable tool for studying corneal physiology and disease. Enabling the dissection of corneal architecture at a cellular level, this technique offers fast and noninvasive in vivo imaging of the cornea with images comparable to those of ex vivo histochemical techniques. Corneal nerves bear substantial relevance to clinicians and scientists alike, given their pivotal roles in regulation of corneal sensation, maintenance of epithelial integrity, as well as proliferation and promotion of wound healing. Thus, IVCM offers a unique method to study corneal nerve alterations in a myriad of conditions, such as ocular and systemic diseases and following corneal surgery, without altering the tissue microenvironment. Of particular interest has been the correlation of corneal subbasal nerves to their function, which has been studied in normal eyes, contact lens wearers, and patients with keratoconus, infectious keratitis, corneal dystrophies, and neurotrophic keratopathy. Longitudinal studies have applied IVCM to investigate the effects of corneal surgery on nerves, demonstrating their regenerative capacity. IVCM is increasingly important in the diagnosis and management of systemic conditions such as peripheral diabetic neuropathy and, more recently, in ocular diseases. In this review, we outline the principles and applications of IVCM in the study of corneal nerves in various ocular and systemic diseases.
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Affiliation(s)
- Andrea Cruzat
- Cornea & Refractive Surgery Service, Department of Ophthalmology, Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, MA, USA; Department of Ophthalmology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Yureeda Qazi
- Cornea & Refractive Surgery Service, Department of Ophthalmology, Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Pedram Hamrah
- Cornea & Refractive Surgery Service, Department of Ophthalmology, Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, MA, USA; Boston Image Reading Center, Tufts Medical Center, Tufts University School of Medicine, Boston, MA; Cornea Service, New England Eye Center, Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA.
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Leckelt J, Guimarães P, Kott A, Ruggeri A, Stachs O, Baltrusch S. Early detection of diabetic neuropathy by investigating CNFL and IENFD in thy1-YFP mice. J Endocrinol 2016; 231:147-157. [PMID: 27601446 DOI: 10.1530/joe-16-0284] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 09/06/2016] [Indexed: 01/19/2023]
Abstract
Small fiber neuropathy is one of the most common and painful long-term complications of diabetes mellitus. Examination of the sub-basal corneal nerve plexus is a promising surrogate marker of diabetic neuropathy. To investigate the efficacy, reliability and reproducibility of in vivo corneal confocal microscopy (IVCCM), we used thy1-YFP mice, which express yellow fluorescence protein (YFP) in nerve fibers. 4 weeks after multiple low-dose injections of streptozotocin, thy1-YFP mice showed manifest diabetes. Subsequent application of insulin-releasing pellets for 8 weeks resulted in a significant reduction of blood glucose concentration and HbA1c, a significant increase in body weight and no further increase in advanced glycation end products (AGEs). IVCCM, carried out regularly over 12 weeks and analyzed both manually and automatically, revealed a significant loss of corneal nerve fiber length (CNFL) during diabetes manifestation and significant recovery after insulin therapy. Ex vivo analyses of CNFL by YFP-based microscopy confirmed the IVCCM results (with high sensitivity between manual and automated approaches) but demonstrated that the changes were restricted to the central cornea. Peripheral areas, not accessible by IVCCM in mice, remained virtually unaffected. Because parallel assessment of intraepidermal nerve fiber density revealed no changes, we conclude that IVCCM robustly captures early signs of diabetic neuropathy.
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Affiliation(s)
- Janine Leckelt
- Institute of Medical Biochemistry and Molecular BiologyUniversity of Rostock, Rostock, Germany
| | - Pedro Guimarães
- Department of Information EngineeringUniversity of Padua, Padua, Italy
| | - Annett Kott
- Institute of Medical Biochemistry and Molecular BiologyUniversity of Rostock, Rostock, Germany
| | - Alfredo Ruggeri
- Department of Information EngineeringUniversity of Padua, Padua, Italy
| | - Oliver Stachs
- Department of OphthalmologyUniversity of Rostock, Rostock, Germany
| | - Simone Baltrusch
- Institute of Medical Biochemistry and Molecular BiologyUniversity of Rostock, Rostock, Germany
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Repeatability of Measuring Corneal Nerve Migration Rate in Individuals With and Without Diabetes. Cornea 2016; 35:1355-61. [DOI: 10.1097/ico.0000000000000913] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Yorek MS, Obrosov A, Lu B, Gerard C, Kardon RH, Yorek MA. Effect of Inhibition or Deletion of Neutral Endopeptidase on Neuropathic Endpoints in High Fat Fed/Low Dose Streptozotocin-Treated Mice. J Neuropathol Exp Neurol 2016; 75:1072-1080. [PMID: 27634964 PMCID: PMC7714044 DOI: 10.1093/jnen/nlw083] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Previously we demonstrated that a vasopeptidase inhibitor of angiotensin converting enzyme and neutral endopeptidase (NEP), a protease that degrades vaso- and neuro-active peptides, improves neural function in diabetic rodent models. The purpose of this study was to determine whether inhibition or deletion of NEP provides protection from neuropathy caused by diabetes with an emphasis on morphology of corneal nerves as a primary endpoint. Diabetes, modeling type 2, was induced in C57Bl/6J and NEP deficient mice through a combination of a high fat diet and streptozotocin. To inhibit NEP activity, diabetic C57Bl/6J mice were treated with candoxatril using a prevention or intervention protocol. Twelve weeks after the induction of diabetes in C57Bl/6J mice, the existence of diabetic neuropathy was determined through multiple endpoints including decrease in corneal nerves in the epithelium and sub-epithelium layer. Treatment of diabetic C57Bl/6J mice with candoxatril improved diabetic peripheral neuropathy and protected corneal nerve morphology with the prevention protocol being more efficacious than intervention. Unlike C57Bl/6J, mice deficient in NEP were protected from the development of neuropathologic alterations and loss of corneal nerves upon induction of diabetes. These studies suggest that NEP contributes to the development of diabetic neuropathy and may be a treatable target.
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Affiliation(s)
- Matthew S Yorek
- From the Department of Veterans Affairs Iowa City Health Care System, Iowa City, IA(MSY, RHK, MAY), Department of Internal Medicine, University of Iowa, Iowa City, IA(AO, MAY), Department of Pediatrics and Medicine, Harvard Medical School, Ina Sue Perlmutter Laboratory, Children's Hospital, Boston, MA(BL), Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA(RHK), Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, IA(RHK, MAY) and Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA(MAY)
| | - Alexander Obrosov
- From the Department of Veterans Affairs Iowa City Health Care System, Iowa City, IA(MSY, RHK, MAY), Department of Internal Medicine, University of Iowa, Iowa City, IA(AO, MAY), Department of Pediatrics and Medicine, Harvard Medical School, Ina Sue Perlmutter Laboratory, Children's Hospital, Boston, MA(BL), Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA(RHK), Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, IA(RHK, MAY) and Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA(MAY)
| | - Bao Lu
- From the Department of Veterans Affairs Iowa City Health Care System, Iowa City, IA(MSY, RHK, MAY), Department of Internal Medicine, University of Iowa, Iowa City, IA(AO, MAY), Department of Pediatrics and Medicine, Harvard Medical School, Ina Sue Perlmutter Laboratory, Children's Hospital, Boston, MA(BL), Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA(RHK), Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, IA(RHK, MAY) and Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA(MAY)
| | - Craig Gerard
- From the Department of Veterans Affairs Iowa City Health Care System, Iowa City, IA(MSY, RHK, MAY), Department of Internal Medicine, University of Iowa, Iowa City, IA(AO, MAY), Department of Pediatrics and Medicine, Harvard Medical School, Ina Sue Perlmutter Laboratory, Children's Hospital, Boston, MA(BL), Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA(RHK), Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, IA(RHK, MAY) and Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA(MAY)
| | - Randy H Kardon
- From the Department of Veterans Affairs Iowa City Health Care System, Iowa City, IA(MSY, RHK, MAY), Department of Internal Medicine, University of Iowa, Iowa City, IA(AO, MAY), Department of Pediatrics and Medicine, Harvard Medical School, Ina Sue Perlmutter Laboratory, Children's Hospital, Boston, MA(BL), Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA(RHK), Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, IA(RHK, MAY) and Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA(MAY)
| | - Mark A Yorek
- From the Department of Veterans Affairs Iowa City Health Care System, Iowa City, IA(MSY, RHK, MAY), Department of Internal Medicine, University of Iowa, Iowa City, IA(AO, MAY), Department of Pediatrics and Medicine, Harvard Medical School, Ina Sue Perlmutter Laboratory, Children's Hospital, Boston, MA(BL), Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA(RHK), Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, IA(RHK, MAY) and Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA(MAY)
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