Assessment of neuron-specific enolase, S100B and malondialdehyde levels in serum and vitreous of patients with proliferative diabetic retinopathy

The role of innate immune system mediators in the development of retinal neurodegeneration in type 2 diabetes mellitus

Purpose. To detect the levels of transform growth factors-β (TGF- β1, TGF- β2, TGF- β3), interferon-ʏ (INF- ʏ), matrix metalloproteinase-9 (MMP-9) and S100B protein in blood serum of patients with type 2 diabetes mellitus (DM) and to reveal the connection of these factors with neurodegenerative changes in the retina. Material and methods. 30 patients, averagely aged 60.3, with type 2 DM and no signs of diabetic retinopathy (DR) (the main group) and 30 healthy individuals (control group) were examined using microperimetry and optical coherence tomography. A sandwich variance estimator of solid phase enzyme-linked immunosorbent assay was used to determine the levels of TGF- β 1, TGF- β2, TGF- β3, INF- ʏ, ММР-9 and S100B protein in blood serum of the subjects examined. Results. The patients with type 2 DM were found to experience an increased level of focal loss of retinal ganglion cells and a drop in the average photosensitivity of the retina. The main group also showed a reliable increase in the level of S100B protein and in the serum level of MMP-9 against the control, but no significant difference between the groups was found in the level of TIMP-1. The level of TGF- β2 was significantly higher in the main group, which also showed a deficiency of TGF- β3. No significant difference was found between the two groups in the levels of TGF- β1 or INF- ʏ. In contrast, a positive correlation was revealed between the levels of S100B, MMP-9 and the volume of focal loss of retinal ganglion cells. Conclusion. Patients with type 2 DM and signs of neurodegeneration of the retina reveal a higher activity of some cytokines and MMP-9. This may indicate an important role of neuroinflammation and dysfunction of the immune system in the retinal neurodegeneration process of DM patients. Further research of other cytokins is required to determine early and more sensitive markers of retinal neurodegeneration.

Astaxanthin Ameliorates Diabetic Retinopathy in Swiss Albino Mice via Inhibitory Processes of Neuron-Specific Enolase Activity

Retinopathy is one of the most common complications of diabetes mellitus. Diabetic retinopathy (DR) occurs due to microvascular damage in retinal tissues provoked by high blood sugar levels. The available drugs for DR are limited. Astaxanthin (AST) has anti-hypertensive, anti-obesity, and anti-diabetic properties. However, the therapeutic effect of AST on DR remains elusive. The present study is designed to investigate the effects of AST on DR via inhibition of neuron-specific enolase (NSE) activity. DR was induced by the administration of streptozotocin (STZ, 35 mg/kg: intraperitoneal; and 20 μL of STZ: intravitreal) in mice. AST (10 and 20 mg/kg) was administered orally (p.o.) for 21 days. The DR associated visual changes were assessed at different time intervals via optokinetic motor response (OMR) and penta-maze (PM) tests. Blood glucose level as well as retinal catalase, lactate dehydrogenase (LDH), & neuron-specific enolase (NSE) were estimated. The reference drug i.e., dexamethasone (DEX, 10 mg/kg; p.o.) was administered for 21 days. The administration of AST showed significant ameliorative potential in DR. Hence, AST can be used as a natural medicine for the management of DR due to its potential antioxidant, anti-diabetic, and NSE inhibitory properties.

Evaluation of serum neuron specific enolase levels among patients with primary and secondary burning mouth syndrome

INTRODUCTION

Burning mouth syndrome is a painful condition of the oral cavity with ambiguous pathogenesis and diagnosis. Neuron-specific enolase is increased in several conditions including peripheral neuropathy of diabetes, ophthalmopathies, spinal cord injuries and tumors. Evidence on association of burning mouth syndrome and neuron-specific enolase is limited.

AIM

This study aims to evaluate neuron-specific enolase levels in primary and secondary burning mouth syndrome patients and compare the levels of neuron-specific enolase with associated conditions in secondary burning mouth syndrome.

METHODS

One hundred and twenty-eight patients of more than 18 years of age with no gender predilection and having clinical symptoms of burning mouth syndrome and 135 healthy subjects were included. All the patients fulfilled Scala's criteria for the diagnosis of burning mouth syndrome, including "primary" (idiopathic) and "secondary" (resulting from identified precipitating factors) burning mouth syndrome patients. Blood samples were obtained from burning mouth syndrome patients. Serum neuron-specific enolase was evaluated using enzyme-linked immunosorbent assay. To compare means and standard deviations, among primary and secondary burning mouth syndrome, data was analysed with analysis of variance and multiple comparisons test.

RESULTS

The mean age of the study participants for burning mouth syndrome and healthy subjects was 53.30 and 51.6 years, respectively. Amongst the secondary burning mouth syndrome group, 32 (25%) of the patients had menopause, 15 (11.7%) had diabetes, eight (6.2%) of the patients had nutritional deficiency, seven (5.4%) had combined diabetes, menopause, and depression, six (4.6%) had combined diabetes and depression, four (3.1%) were diagnosed with Sjögren's syndrome. A minor percentage of 2.3% (three) had gastroesophageal reflux disease, while the remaining three (2.3%) patients in the secondary burning mouth syndrome group were on anti-depressants. There was a statistically significant increase in the levels of neuron-specific enolase in primary burning mouth syndrome as compared to the secondary burning mouth syndrome and healthy groups. Among the subgroups of secondary burning mouth syndrome, diabetic individuals showed a significant increase in neuron-specific enolase level when compared with other conditions in the secondary burning mouth syndrome patients.Discussion and conclusion: The raised serum neuron-specific enolase levels in patients suffering from primary burning mouth syndrome highlight a possible neuropathic mechanism. It was also increased in the sub-group of secondary burning mouth syndrome patients having diabetes. Although it cannot be ascertained whether the deranged values in the diabetic group were due to burning mouth syndrome or due to diabetes, the raised quantity of neuron-specific enolase in the primary burning mouth syndrome group is a reliable diagnostic indicator. Future studies on the assessment of neuron-specific enolase levels as a diagnostic tool for onset and management of primary and secondary burning mouth syndrome are recommended.

Low-Level Laser Therapy with 670 nm Alleviates Diabetic Retinopathy in an Experimental Model

Purpose:

To evaluate the effects of low-level laser therapy (LLLT) on the retina with diabetic retinopathy (DR).

Methods:

Eight Wistar rats were used as a control group, and 64 rats were injected intraperitoneally with 55 mg/kg of streptozotocin to induce diabetes and served as a diabetic group. After the establishment of the DR, the rats were separated into (a) 32 rats with DR; did not receive any treatment, (b) 32 rats with DR were exposed to 670 nm LLLT for 6 successive weeks (2 sessions/week). The retinal protein was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, total antioxidant capacity (TAC), hydrogen peroxide (H₂O₂), and histological examination.

Results:

LLLT improved retinal proteins such as neurofilament (NF) proteins (200 KDa, 160 KDa, and 86 KDa), neuron-specific enolase (NSE) (46 KDa). Moreover, the percentage changes in TAC were 46.8% (P < 0.001), 14.5% (P < 0.01), 4.8% and 1.6% (P > 0.05), and in H₂O_2, they were 30% (P < 0.001), 25% (P < 0.001), 20% (P < 0.01), and 5% (P > 0.05) after 1, 2, 4, and 6 weeks, compared with the control. DR displayed swelling and disorganization in the retinal ganglion cells (RGCs) and photoreceptors, congestion of the capillaries in the nerve fiber layer, thickening of the endothelial cells’ capillaries, and edema of the outer segment of the photoreceptors layer. The improvement of the retinal structure was achieved after LLLT.

Conclusion:

LLLT could modulate retinal proteins such as NSE and NFs, improve the RGCs, photoreceptors, and reduce the oxidative stress that originated in the retina from diabetes-induced DR.

The Role of Lipoxidation in the Pathogenesis of Diabetic Retinopathy

Lipids can undergo modification as a result of interaction with reactive oxygen species (ROS). For example, lipid peroxidation results in the production of a wide variety of highly reactive aldehyde species which can drive a range of disease-relevant responses in cells and tissues. Such lipid aldehydes react with nucleophilic groups on macromolecules including phospholipids, nucleic acids, and proteins which, in turn, leads to the formation of reversible or irreversible adducts known as advanced lipoxidation end products (ALEs). In the setting of diabetes, lipid peroxidation and ALE formation has been implicated in the pathogenesis of macro- and microvascular complications. As the most common diabetic complication, retinopathy is one of the leading causes of vision loss and blindness worldwide. Herein, we discuss diabetic retinopathy (DR) as a disease entity and review the current knowledge and experimental data supporting a role for lipid peroxidation and ALE formation in the onset and development of this condition. Potential therapeutic approaches to prevent lipid peroxidation and lipoxidation reactions in the diabetic retina are also considered, including the use of antioxidants, lipid aldehyde scavenging agents and pharmacological and gene therapy approaches for boosting endogenous aldehyde detoxification systems. It is concluded that further research in this area could lead to new strategies to halt the progression of DR before irreversible retinal damage and sight-threatening complications occur.

High Serum Neuron-Specific Enolase Level Is Associated with Mild Cognitive Impairment in Patients with Diabetic Retinopathy

PURPOSE

Diabetic retinopathy (DR) can increase the risk of mild cognitive impairment (MCI), which has been confirmed by previous researches. With the frequent occurrence of MCI in patients with DR, the early detection of MCI has become a research hot-spot. The aim of this study was to investigate the relationship between neuron-specific enolase (NSE) and MCI in patients with DR.

PATIENTS AND METHODS

A total of 124 patients with DR, including 56 MCI patients and 68 normal cognition patients, were recruited in this cross-sectional study. The demographic and clinical data of patients were collected through questionnaires. Serum NSE was measured using electrochemiluminescence immunoassay. The Minimum Mental State Examination (MMSE) scale was used to evaluate the cognitive function of the participants.

RESULTS

Compared with the normal cognition group, serum NSE levels and HbA1c levels in the MCI group were higher, while MMSE scores and educational level were lower (P<0.05). Serum NSE levels were significantly negatively correlated with MMSE total score, attention and calculation score, and language score (P<0.05). After adjusting for confounding factors, serum NSE still increased the MCI risk in DR patients (OR:1.606, 95CI%:1.264-2.041, P<0.001). The areas under the receiver operating characteristics (ROC) curves (AUC) of the crude model and the adjusted model were 0.75 and 0.73, respectively.

CONCLUSION

A high serum NSE level is an independent risk factor for MCI in DR patients. In addition, serum NSE is expected to be a potential biomarker in DR patients with MCI.