Augmented Corneal Nerve Fiber Branching in Painful Compared With Painless Diabetic Neuropathy

AbstractContextThe factors that determine the development of diabetic sensorimotor polyneuropathy (DSPN) as a painful or painless entity are unknown.ObjectiveWe hypothesized that corneal nerve pathology could be more pronounced in painful DSPN, indicating predominant small nerve fiber damage.Design and MethodsIn this cross-sectional study, we assessed 53 patients with painful DSPN, 63 with painless DSPN, and 46 glucose-tolerant volunteers by corneal confocal microscopy (CCM), nerve conduction (NC), and quantitative sensory testing. DSPN was diagnosed according to modified Toronto Consensus criteria. A cutoff at 4 points on the 11-point rating scale was used to differentiate between painful and painless DSPN.ResultsAfter adjustment for age, sex, body mass index, and smoking, corneal nerve fiber density, corneal nerve fiber length, and corneal nerve branch density (CNBD) were reduced in both DSPN types compared with the control group (P < 0.05). Only CNBD differed between the groups; it was greater in patients with painful DSPN compared with those with painless DSPN [55.8 (SD, 29.9) vs 43.8 (SD, 28.3) branches/mm2; P < 0.05]. Several CCM measures were associated with NC and cold perception threshold in patients with painless DSPN (P < 0.05) but not those with painful DSPN.ConclusionDespite a similarly pronounced peripheral nerve dysfunction and corneal nerve fiber loss in patients with painful and painless DSPN, corneal nerve branching was enhanced in those with painful DSPN, pointing to some susceptibility of corneal nerve fibers toward regeneration in this entity, albeit possibly not to a sufficient degree.

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Corneal nerve fiber loss relates to cognitive impairment in patients with Parkinson’s disease

npj Parkinson s Disease ◽

10.1038/s41531-021-00225-3 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Ning-Ning Che ◽

Qiu-Huan Jiang ◽

Guan-Xiao Ding ◽

Si-Yuan Chen ◽

Zhen-Xiang Zhao ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Cognitive Impairment ◽

Cognitive Function ◽

Nerve Fiber ◽

Rating Scale ◽

Motor Dysfunction ◽

Control Group ◽

Corneal Confocal Microscopy ◽

Corneal Nerve

AbstractCognitive impairment in Parkinson’s disease (PD) adversely influences quality of life. There is currently no available biomarker to predict cognitive decline in PD. Corneal confocal microscopy (CCM) has been used as a non-invasive tool for quantifying small nerve damage in PD. The present study investigated whether corneal nerve measures were associated with cognitive function in PD. Patients with PD were classified into those with normal cognitive function (PD-CN), mild cognitive impairment (PD-MCI), and dementia (PDD). Corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), and corneal nerve fiber length (CNFL) were quantified with CCM and compared with a control group. Sixty-five PD patients and thirty controls were studied. CNFD was decreased and CNBD was increased in PD patients compared to controls (P < 0.05). CNBD and CNBD/CNFD ratio was higher in PD-CN compared to controls. CNFD was positively correlated with the Montreal cognitive assessment (MoCA) score (r = 0.683, P < 0.001), but negatively associated with unified Parkinson disease rating scale (UPDRS)-part III (r = −0.481, P < 0.001) and total UPDRS scores (r = −0.401, P = 0.001) in PD patients. There was no correlation between CNFD and Levodopa equivalent daily dose (LEDD) (r = 0.176, P = 0.161). CNFD, CNBD, CNFL, and CNBD/CNFD ratio was lower with increasing Hoehn and Yahr stage. PD patients show evidence of corneal nerve loss compared with controls and corneal nerve parameters are associated with the severity of cognitive and motor dysfunction in PD. CCM could serve as an objective in vivo ophthalmic imaging technique to assess neurodegeneration in PD.

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Early detection of diabetic neuropathy by investigating CNFL and IENFD in thy1-YFP mice

Journal of Endocrinology ◽

10.1530/joe-16-0284 ◽

2016 ◽

Vol 231 (2) ◽

pp. 147-157 ◽

Cited By ~ 8

Author(s):

Janine Leckelt ◽

Pedro Guimarães ◽

Annett Kott ◽

Alfredo Ruggeri ◽

Oliver Stachs ◽

...

Keyword(s):

Diabetic Neuropathy ◽

Nerve Fiber ◽

Blood Glucose Concentration ◽

Ex Vivo ◽

Surrogate Marker ◽

Nerve Fibers ◽

Fiber Density ◽

Corneal Confocal Microscopy ◽

Intraepidermal Nerve Fiber Density ◽

Corneal Nerve

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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Corneal Nerve Loss in Patients With TIA and Acute Ischemic Stroke in Relation To Circulating Markers of Inflammation and Vascular Integrity

10.21203/rs.3.rs-301595/v2 ◽

2021 ◽

Author(s):

Adnan Khan ◽

Aijaz Parray ◽

Naveed Akhtar ◽

Abdelali Agouni ◽

Saadat Kamran ◽

...

Keyword(s):

Ischemic Stroke ◽

Cerebrovascular Disease ◽

Acute Ischemic Stroke ◽

Nerve Fiber ◽

Fiber Density ◽

Nerve Branch ◽

Vascular Integrity ◽

Markers Of Inflammation ◽

Corneal Confocal Microscopy ◽

Corneal Nerve

Abstract Background Vascular and inflammatory mechanisms are implicated in the development of cerebrovascular disease and corneal nerve loss occurs in patients with transient ischemic attack (TIA) and acute ischemic stroke (AIS). We have assessed whether serum markers of inflammation and vascular integrity are associated with the severity of corneal nerve loss in patients with TIA and AIS. Methods Corneal confocal microscopy (CCM) was performed to quantify corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), corneal nerve fiber length (CNFL) in 105 patients with TIA or AIS and age matched control subjects (n=56). Circulating levels of IL-6, MMP-2, MMP-9, E-Selectin, P-Selectin and VEGF were quantified in patients within 48 hours of presentation with a TIA or AIS. Results CNFL (P=0.000, P=0.000), CNFD (P=0.122, P=0.000) and CNBD (P=0.002, P=0.000) were reduced in patients with TIA and AIS compared to controls, respectively with no difference between patients with AIS and TIA. The NIHSS Score (P=0.000), IL-6 (P=0.011) and E-Selectin (P=0.032) were higher in patients with AIS compared to TIA with no difference in MMP-2 (P=0.636), MMP-9 (P=0.098), P-Selectin (P=0.395) and VEGF (P=0.831). CNFL (r=0.218, P=0.026) and CNFD (r=0.230, P=0.019) correlated with IL-6 and multiple regression analysis showed a positive association of CNFL and CNFD with IL-6 (P=0.041, P=0.043). Conclusions Patients with TIA and stroke have evidence of corneal nerve loss and elevated IL6 and E-selectin levels. Larger longitudinal studies are required to determine the association between inflammatory and vascular markers and corneal nerve fiber loss in patients with cerebrovascular disease.

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Corneal Confocal Microscopy to Image Small Nerve Fiber Degeneration: Ophthalmology Meets Neurology

Frontiers in Pain Research ◽

10.3389/fpain.2021.725363 ◽

2021 ◽

Vol 2 ◽

Author(s):

Ioannis N. Petropoulos ◽

Gulfidan Bitirgen ◽

Maryam Ferdousi ◽

Alise Kalteniece ◽

Shazli Azmi ◽

...

Keyword(s):

Confocal Microscopy ◽

Diabetic Neuropathy ◽

Nerve Fiber ◽

Clinical Intervention ◽

Nerve Fibers ◽

Fiber Density ◽

Corneal Confocal Microscopy ◽

Intraepidermal Nerve Fiber Density ◽

Corneal Nerve ◽

Small Nerve

Neuropathic pain has multiple etiologies, but a major feature is small fiber dysfunction or damage. Corneal confocal microscopy (CCM) is a rapid non-invasive ophthalmic imaging technique that can image small nerve fibers in the cornea and has been utilized to show small nerve fiber loss in patients with diabetic and other neuropathies. CCM has comparable diagnostic utility to intraepidermal nerve fiber density for diabetic neuropathy, fibromyalgia and amyloid neuropathy and predicts the development of diabetic neuropathy. Moreover, in clinical intervention trials of patients with diabetic and sarcoid neuropathy, corneal nerve regeneration occurs early and precedes an improvement in symptoms and neurophysiology. Corneal nerve fiber loss also occurs and is associated with disease progression in multiple sclerosis, Parkinson's disease and dementia. We conclude that corneal confocal microscopy has good diagnostic and prognostic capability and fulfills the FDA criteria as a surrogate end point for clinical trials in peripheral and central neurodegenerative diseases.

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Corneal nerve loss in patients with TIA and acute ischemic stroke in relation to circulating markers of inflammation and vascular integrity

10.21203/rs.3.rs-301595/v1 ◽

2021 ◽

Author(s):

Adnan Khan ◽

Aijaz Parray ◽

Naveed Akhtar ◽

Abdelali Agouni ◽

Saadat Kamran ◽

...

Keyword(s):

Ischemic Stroke ◽

Cerebrovascular Disease ◽

Acute Ischemic Stroke ◽

Nerve Fiber ◽

Fiber Density ◽

Nerve Branch ◽

Vascular Integrity ◽

Markers Of Inflammation ◽

Corneal Confocal Microscopy ◽

Corneal Nerve

Abstract Background Vascular and inflammatory mechanisms are implicated in the development of cerebrovascular disease and corneal nerve loss occurs in patients with transient ischemic attack (TIA) and acute ischemic stroke (AIS). We have assessed whether serum markers of inflammation and vascular integrity are associated with the severity of corneal nerve loss in patients with TIA and AIS. Methods Corneal confocal microscopy (CCM) was performed to quantify corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), corneal nerve fiber length (CNFL) in 105 patients with TIA or AIS and age matched control subjects (n = 56). Circulating levels of IL-6, MMP-2, MMP-9, E-Selectin, P-Selectin and VEGF were quantified in patients within 48 hours of presentation with a TIA or AIS. Results CNFL (P = 0.000, P = 0.000), CNFD (P = 0.122, P = 0.000) and CNBD (P = 0.002, P = 0.000) were reduced in patients with TIA and AIS compared to controls, respectively with no difference between patients with AIS and TIA. The NIHSS Score (P = 0.000), IL-6 (P = 0.011) and E-Selectin (P = 0.032) were higher in patients with AIS compared to TIA with no difference in MMP-2 (P = 0.636), MMP-9 (P = 0.098), P-Selectin (P = 0.395) and VEGF (P = 0.831). CNFL (r = 0.218, P = 0.026) and CNFD (r = 0.230, P = 0.019) correlated with IL-6 and multiple regression analysis showed a positive association of CNFL and CNFD with IL-6 (P = 0.041, P = 0.043). Conclusions Patients with TIA and stroke have evidence of corneal nerve loss and elevated IL6 and E-selectin levels. Larger longitudinal studies are required to determine the association between inflammatory and vascular markers and corneal nerve fiber loss in patients with cerebrovascular disease.

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Corneal Nerve Fiber Loss Relates to Cognitive Impairment in Patients with Parkinson’s Disease

10.21203/rs.3.rs-112941/v1 ◽

2020 ◽

Author(s):

Ning-Ning Che ◽

Qiu-Huan Jiang ◽

Guan-Xiao Ding ◽

Si-Yuan Chen ◽

Zhen-Xiang Zhao ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Cognitive Impairment ◽

Cognitive Function ◽

Nerve Fiber ◽

Rating Scale ◽

Motor Dysfunction ◽

Control Group ◽

Corneal Confocal Microscopy ◽

Corneal Nerve

Abstract Background Cognitive impairment in Parkinson’s disease (PD) adversely influences quality of life. There is currently no available biomarker to predict cognitive decline in PD. PD involves both the central and peripheral nervous system and especially small fiber damage occurs in PD. Corneal confocal microscopy (CCM) has been used as a non-invasive tool for quantifying small nerve fibre damage in PD. The present study investigated whether corneal nerve measures were associated with cognitive function in PD. Methods Patients with PD were classified into those with normal cognitive function (PD-CN), mild cognitive impairment (PD-MCI), and dementia (PDD). Corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD) and corneal nerve fiber length (CNFL) were quantified with CCM and compared with a control group.Results Sixty-five PD patients (44.62% male; mean age 64.60±6.95 years; mean disease duration 4.63±2.53 years) and 30 controls (53.33% male; mean age 62.43±6.16 years) were studied. CNFD was decreased and CNBD was increased in PD patients compared to controls ( P <0.05). CNFD decreased progressively with decline in cognitive function in PD patients. CNBD and CNBD/CNFD ratio was higher in PD-CN compared to controls but decreased with worsening cognitive function in PD-MCI and PDD patients. CNFD correlated with the Montreal cognitive assessment (MoCA) score ( r =0.683, P <0.0001), unified Parkinson disease rating scale (UPDRS)-part III ( r =-0.481, P <0.0001) and total UPDRS scores ( r =-0.401, P <0.0001) in PD patients. CNFD, CNBD, CNFL were lower and CNBD/CNFD ratio was higher with increasing Hoehn and Yahr stage. There was no correlation between CNFD and Levodopa equivalent daily dose (LEDD) ( r =0.176, P =0.161). CNFD, CNBD and CNFL could discriminate between PD-MCI and PD-CN with an area under the curve (AUC) of 82.85%, 67.47%, and 78.74%, respectively. CNFD, CNBD and CNFL could discriminate between PDD and PD-CN with an AUC of 96.67%, 90.12% and 84.44%. A combination of all three CCM parameters further increased the AUC value. Conclusions PD patients show evidence of corneal nerve loss compared with controls and corneal nerve parameters are associated with the severity of cognitive and motor dysfunction in PD. CCM could serve as an objective in vivo ophthalmic imaging technique to assess neurodegeneration in PD.

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Assessment and comparison of the morphology and function of the corneal sub-basal nerve plexus in type-1 diabetes mellitus patients and in healthy subjects

Modeling and Artificial Intelligence in Ophthalmology ◽

10.35119/maio.v1i1.14 ◽

2016 ◽

Vol 1 (1) ◽

pp. 51-63

Author(s):

Irmante Derkac ◽

Ingrida Januleviciene ◽

Kirwan Asselineau ◽

Dzilda Velickiene

Keyword(s):

Nerve Fiber ◽

Healthy Subjects ◽

Nerve Fibers ◽

Corneal Sensitivity ◽

Fiber Density ◽

Corneal Confocal Microscopy ◽

Corneal Nerve ◽

Type 1 Dm ◽

Nerve Fiber Density

Aim/purpose: It is believed that small nerve bundles are damaged in the earliest stages of neuropathy caused by diabetes mellitus (DM). Our goal was to evaluate and compare anatomical characteristics of corneal nerve fibers and corneal sensitivity in type-1 DM patients and in healthy control subjects.Design: A prospective, masked, controlled cross-sectional clinical study.Method: Thirty patients with type-1 DM and ten non-diabetic healthy subjects underwent a corneal confocal microscopy to evaluate the corneal sub-basal nerve fibers (density, number of nerves and branches, total nerve length) and contact corneal esthesiometry.Results: Diabetic patients had significantly lower corneal nerve fiber density density (14.32 ± 5.87 vs. 19.71 ± 5.59 mm/mm2; p = 0.023 ) nerve branches number (4.57 ± 3,91 vs. 9.90 ± 5.8 n°/image; p = 0.006) , nerve fiber length (2.28 ± 0.94 vs. 3.13 ± 0.89 mm; p = 0.032) and corneal sensitivity (1.13 ± 0.29 vs. 0.98 ± 0.058 gr/mm2 p = 0.02), as compared with controls. A negative correlation was found between corneal nerve fiber length, corneal nerve number, corneal nerve fiber density and disease duration (p < 0.05).Conclusion: Corneal confocal microscopy and corneal sensitivity evaluation are noninvasive techniques helping to detect early changes in the sub-basal nerve plexus characteristic for diabetic neuropathy (DN) in patients with type-1 DM. Further studies are required to investigate the role of corneal neuropathy assessment using these novel techniques as a toll to detect early DN.

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Corneal nerve quantification predicts the severity of symptoms in sarcoidosis patients with painful neuropathy

TECHNOLOGY ◽

10.1142/s2339547813500039 ◽

2013 ◽

Vol 01 (01) ◽

pp. 20-26 ◽

Cited By ~ 6

Author(s):

M. Brines ◽

M. Swartjes ◽

M.R. Tannemaat ◽

A. Dunne ◽

M. van Velzen ◽

...

Keyword(s):

Nerve Fiber ◽

Adult Population ◽

Brief Pain Inventory ◽

The United States ◽

Fiber Density ◽

Painful Neuropathy ◽

Small Fiber ◽

Corneal Confocal Microscopy ◽

Fiber Number ◽

Corneal Nerve

Small fiber neuropathy (SFN) is a debilitating condition characterized by chronic pain as well as sensory and autonomic dysfunction. SFN is an increasingly recognized component of a large number of diseases, including sarcoidosis. Although affecting an estimated 2–3% of the adult population in the United States, it often remains undiagnosed. Skin biopsy for evaluating intra-epidermal nerve fiber density (IENFD) and more recently corneal confocal microscopy (CCM) have been used to identify small fiber damage in patients with neuropathy. We demonstrate a significant reduction in IENFD, corneal nerve fiber number and length, with no change in the number of branches in patients with painful sarcoid neuropathy. Moreover, unlike IENFD, corneal nerve fiber number and length inversely correlate with the degree to which pain interferes with activities of daily living as assessed by the Brief Pain Inventory questionnaire. CCM thus constitutes an accurate, non-invasive assessment technique to aid in the diagnosis of SFN, as well as an objective marker of symptoms in patients with painful sarcoid neuropathy.

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Corneal confocal microscopy demonstrates axonal loss in different courses of multiple sclerosis

Scientific Reports ◽

10.1038/s41598-021-01226-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ioannis N. Petropoulos ◽

Kathryn C. Fitzgerald ◽

Jonathan Oakley ◽

Georgios Ponirakis ◽

Adnan Khan ◽

...

Keyword(s):

Multiple Sclerosis ◽

Confocal Microscopy ◽

Nerve Fiber ◽

Clinically Isolated Syndrome ◽

Axonal Loss ◽

Fiber Density ◽

Corneal Confocal Microscopy ◽

Segmentation Methods ◽

Relapsing Remitting ◽

Corneal Nerve

AbstractAxonal loss is the main determinant of disease progression in multiple sclerosis (MS). This study aimed to assess the utility of corneal confocal microscopy (CCM) in detecting corneal axonal loss in different courses of MS. The results were confirmed by two independent segmentation methods. 72 subjects (144 eyes) [(clinically isolated syndrome (n = 9); relapsing–remitting MS (n = 20); secondary-progressive MS (n = 22); and age-matched, healthy controls (n = 21)] underwent CCM and assessment of their disability status. Two independent algorithms (ACCMetrics; and Voxeleron deepNerve) were used to quantify corneal nerve fiber density (CNFD) (ACCMetrics only), corneal nerve fiber length (CNFL) and corneal nerve fractal dimension (CNFrD). Data are expressed as mean ± standard deviation with 95% confidence interval (CI). Compared to controls, patients with MS had significantly lower CNFD (34.76 ± 5.57 vs. 19.85 ± 6.75 fibers/mm2, 95% CI − 18.24 to − 11.59, P < .0001), CNFL [for ACCMetrics: 19.75 ± 2.39 vs. 12.40 ± 3.30 mm/mm2, 95% CI − 8.94 to − 5.77, P < .0001; for deepNerve: 21.98 ± 2.76 vs. 14.40 ± 4.17 mm/mm2, 95% CI − 9.55 to − 5.6, P < .0001] and CNFrD [for ACCMetrics: 1.52 ± 0.02 vs. 1.45 ± 0.04, 95% CI − 0.09 to − 0.05, P < .0001; for deepNerve: 1.29 ± 0.03 vs. 1.19 ± 0.07, 95% − 0.13 to − 0.07, P < .0001]. Corneal nerve parameters were comparably reduced in different courses of MS. There was excellent reproducibility between the algorithms. Significant corneal axonal loss is detected in different courses of MS including patients with clinically isolated syndrome.

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Corneal confocal microscopy compared with quantitative sensory testing and nerve conduction for diagnosing and stratifying the severity of diabetic peripheral neuropathy

BMJ Open Diabetes Research & Care ◽

10.1136/bmjdrc-2020-001801 ◽

2020 ◽

Vol 8 (2) ◽

pp. e001801

Author(s):

Maryam Ferdousi ◽

Alise Kalteniece ◽

Shazli Azmi ◽

Ioannis N Petropoulos ◽

Anne Worthington ◽

...

Keyword(s):

Diabetic Neuropathy ◽

Nerve Fiber ◽

Nerve Conduction ◽

Fiber Length ◽

Quantitative Sensory Testing ◽

Sensory Testing ◽

Perception Threshold ◽

Corneal Confocal Microscopy ◽

Corneal Nerve ◽

Vibration Perception

IntroductionDiabetic neuropathy can be diagnosed and assessed using a number of techniques including corneal confocal microscopy (CCM).Research design and methodsWe 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).ResultsVibration 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%).ConclusionThis 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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