Original Article
Change in tear protein profile in diabetic retinopathy with duration of diabetes

https://doi.org/10.1016/j.dsx.2014.09.019Get rights and content

Abstract

Aims

To study change in tear protein profile with duration of diabetes and severity of diabetic retinopathy (DR) in type 2 diabetes patients.

Materials and methods

Tear protein profile was ascertained by SDS PAGE method in 30 patients with DR (group A) and 37 patients without DR (group B).

Results

Six distinct bands of proteins were identified; these proteins are as follows: 91 kDa (P1), 66 kDa (P2), 60 kDa (P3), 30 kDa (P4), 18.4 kDa (P5) and 14.4 kDa (P6). Prevalence of P3 was significant (p = 0.036) in group A, especially in cases with diabetes ≤8 years compared with diabetes >8 years (p = 0.0107). In group B, P2 was significantly prevalent (p < 0.0013) in cases with diabetes ≤8 years compared to diabetes >8 years. Considering the changes in terms of duration of diabetes in general, patients with diabetes of ≤8 years, P3 was significantly prevalent in group A compared to group B (p = 0.004); and when the duration of diabetes is >8 years, P2 was found significantly more in group A compared to group B (p = 0.01). No significant difference in P3 (p = 0.025), P4 (p = 0.2877), P5 (p = 0.4801), P6 (p = 0.0985) was observed in mild to moderate NPDR group compared to severe NPDR to PDR group. P1 and P2 were present only in severe NPDR and PDR.

Conclusion

Variable protein expression was observed with duration of diabetes and severity of diabetic retinopathy.

Introduction

Tear is a biochemical mixture containing electrolytes, proteins, lipids, mucin and organic metabolites. Tear of normal adults contains 6 to 10 mg/ml of total proteins. Four major proteins are found consistently on gel slabs: lactoferrin, lysozyme and two tear specific proteins [1].

Up or down regulation of tear proteins may occur in diabetes mellitus (DM) and dry eye disease [2], [3]. Dry eye is common in DM and its severity has been shown to correlate with the severity of diabetic retinopathy (DR) [3], [4]. The tear protein profile in DM is different from that of healthy subjects and this alteration is correlated with the duration of the disease [5].

As duration of diabetes is also the most important risk factor for DR, tear protein profile in DR may also vary with disease duration. Identification of any change in protein profile may help in future in finding out noninvasive biomarker(s) for DR.

Aim of the study was to identify tear proteins in DM patients with and without DR and look for any association of the proteins with the duration of diabetes and severity of DR.

Section snippets

Method

The study population comprised of selected patients above 30 years of age with type 2 DM attending one tertiary referral Institute in Kolkata, India. They were invited to participate with written informed consent. The diagnosis of diabetes was based on previous biochemical reports or treatment history of diabetes. Patients with any ocular surface disease, dry eye (Schirmer test result <5 mm), scarring, acute ocular infection, blepharitis, contact lens wear during study were excluded. Consecutive

Result

In group A 14 (43.8%) were male and 18 (56.2%) were female. In group B 17 (45.9%) were male and 20 (54.1%) were female. Mean age was 55.1 ± 7.9 and 53.2 ± 8.3 years in groups A and B, respectively with no significant difference (p = 0.328).

Mean duration of diabetes in group A was 9.3 ± 2.3 years with a median of 8 years. Mean duration of diabetes was 4.9 ± 1.8 years in group B with a median of 3 years. There was significant difference in duration between two groups (p = 0.003).

Out of 30 eyes in group A, 12

Discussion

In this study, duration of diabetes was significantly more in patients with DR compared to those without DR as we compared the two age and sex matched groups.

This observation is consistent with the already known fact that duration is the most important risk factor for development of DR [4].

We observed that in the presence of 60 kDa (P3) protein in patients with lesser duration (≤8 years) and lower degree of retinopathy (mild and moderate NPDR) and the presence of 66 kDa (P2) protein in patients

Financial support

This paper was supported by short term student project of Indian Council of Medical Research.

Acknowledgements

Acknowledge Dr. D. Maji, MAE and Dr. B.P. Mukhopadhyay, MAE for help in statistical work. The study was funded by Indian Council of Medical Research in the form of grant for short term student project.

Conflict of interest: None.

References (16)

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