Evaluation of Aqueous Humor DEL-1 and IL-17 Levels in Diabetic Cataract Patients

Developmental Endothelial Locus-1 (DEL-1) is a molecule related to endothelial cells and is a protein involved in intercellular interactions. It is generally associated with the development and function of endothelial cells lining the inner surface of the vessel. It plays an important role in the regulation of inflammation, the development of vessels and the organization of endothelial cells. It has also been shown to be associated with some types of cancer. It may also be effective in tissue regeneration and healing of injuries.

IL-17 (Interleukin-17) is a group of cytokines that play an important role in the immune system. There are several subtypes of IL-17, the best known and most researched being IL-17A. It regulates the body's immune response to certain infections. It is an important cytokine that initiates and supports the inflammation process. IL-17 plays an important role in the pathogenesis of various autoimmune and inflammatory diseases.

DEL-1 and IL-17 are two different molecules that act on inflammation and immune responses. DEL-1 helps regulate inflammation by protecting vascular health, while IL-17 can accelerate the course of diseases by increasing inflammation.

Diabetes is a systemic disease associated with oxidative stress and chronic inflammation. Retinopathy, cataract and glaucoma diseases develop due to diabetes. DEL-1 is a protein involved in the maintenance of vascular homeostasis and regulation of inflammation. Since diabetic patients have chronic inflammation and microvascular dysfunction, changes in DEL-1 levels may provide important clues to the pathophysiology

• Observational Study Procedure (Other): No intervention was administered. This was a prospective observational case-control study. Participants underwent routine ophthalmologic examinations and aqueous humor sampling during cataract surgery.

Primary outcomes

• DEL-1 and IL-17 Levels [During cataract surgery, at the time of aqueous humor collection]: Aqueous humor DEL-1 and IL-17 concentrations were measured quantitatively using ELISA and are reported in pg/mL.

Secondary outcomes

• HbA1c [Preoperative, before cataract surgery]: Blood HbA1c concentrations were measured in all study participants and are reported as percentage (%).
• Association Between Aqueous Humor DEL-1 and IL-17 Levels [During cataract surgery, at the time of aqueous humor collection]: Spearman correlation analyses were performed to evaluate the association between aqueous humor DEL-1 and IL-17 concentrations separately for the Diabetic Cataract Group and the Control Group. Spearman's correlation coefficients (rho) are reported for each study arm.
• Association of Biomarker Levels With HbA1c [Perioperative, based on the most recent HbA1c measurement available before cataract surgery]: Spearman correlation analyses were performed separately for the Diabetic Cataract Group and the Control Group to evaluate the associations between aqueous humor DEL-1 and IL-17 concentrations and HbA1c. Spearman's correlation coefficients (rho) are reported for each study arm.
• Association Between Demographic Variables and DEL-1/IL-17 Levels [During cataract surgery, at the time of aqueous humor collection]: Spearman correlation analyses were performed to evaluate the associations between demographic variables and aqueous humor DEL-1 and IL-17 concentrations separately for the Diabetic Cataract Group and the Control Group. Correlation coefficients are reported for each study arm.

Sex: All, ages: 50 Years to 80 Years, accepts healthy volunteers

Inclusion Criteria:

* Cataract diagnosed and surgery planned
* Patients without any other ocular pathology other than cataract.
* Type 2 DM for at least 5 years in the diabetic group

Exclusion Criteria:

* Patients with previous intraocular surgery
* Those with inflammatory eye diseases (e.g. uveitis)
* Those with autoimmune diseases or systemic inflammatory diseases
* Those receiving local or systemic steroid therapy
* Those with severe systemic disease (e.g. advanced renal failure, malignancy)

Participant flow

Outcome results

• DEL-1 and IL-17 Levels (Primary), Mean, pg/mL: Diabetic Cataract Group 0.27 +/- 0.21; Control Group 0.36 +/- 0.3
• HbA1c (Secondary), Mean, percentage: Diabetic Cataract Group 7.32 +/- 1.22; Control Group 5.26 +/- 0.47
• Association Between Aqueous Humor DEL-1 and IL-17 Levels (Secondary), Number, Correlation coefficient: Diabetic Cataract Group 0.157; Control Group (Non-Diabetic Cataract) 0.423
• Association of Biomarker Levels With HbA1c (Secondary), Number, Correlation coefficient: Diabetic Cataract Group 0.149; Control Group (Non-Diabetic Cataract) 0.321
• Association Between Demographic Variables and DEL-1/IL-17 Levels (Secondary), Number, Correlation coefficient: Diabetic Cataract Group -0.038; Control Group (Non-Diabetic Cataract) -0.269

Adverse events

Time frame: Deaths and Adverse Events were not collected as part of this observational biomarker study

Limitations and caveats: This study had a relatively small sample size and was limited to patients undergoing cataract surgery at a single center, which may affect the generalizability of the findings. Additionally, the cross-sectional design precludes assessment of causality or long-term dynamics of DEL-1 and IL-17 levels. The absence of patients with diabetic retinopathy limits the ability to evaluate the role of these markers in advanced ocular inflammation.

• Results publication: Dogruya S, Sagkan RI. Levels of DEL-1 and IL-17 in the aqueous humor of cataract patients with diabetes without diabetic retinopathy. Int Ophthalmol. 2026 Jun 25;46(1):270. doi: 10.1007/s10792-026-04142-3. PMID 42347979

• Study Protocol and Statistical Analysis Plan (PDF, 2026-07-20)