Serum Cathepsin G Levels and Their Relationship with Glycemic and Inflammatory Markers in Type 2 Diabetes Mellitus

Öz

Cathepsin G (CatG), a neutrophil-derived serine protease, contributes to inflammation and vascular remodeling. Dysregulated CatG activity has been implicated in autoimmune and metabolic disorders; however, its role in type 2 diabetes mellitus (T2DM) remains insufficiently characterized. This cross-sectional study investigated serum CatG levels in 76 patients with T2DM and 37 healthy controls. CatG levels were measured using ELISA, and metabolic and inflammatory indices—including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), systemic immune–inflammation index (SII), and triglyceride-to–high-density lipoprotein cholesterol ratio (TG/HDL)—were assessed. Serum CatG levels were significantly lower in patients with T2DM than in controls (685.6±480.8 vs. 995.4±721.9 pg/mL; p=0.011). In unadjusted analyses, T2DM was negatively associated with CatG levels (B=−309.8; p=0.008); however, this association was no longer statistically significant after adjustment for age, sex, waist circumference, and PLR (p=0.139), indicating attenuation of the crude between-group difference. These findings suggest that baseline demographic and anthropometric imbalances may partly contribute to the observed differences in CatG levels. Serum CatG levels were inversely correlated with HbA1c, fasting plasma glucose, and waist circumference, while no significant associations were observed with inflammatory indices. Despite evidence of low-grade inflammation in T2DM, CatG levels did not parallel NLR, PLR, or SII. Reduced serum CatG levels may therefore be associated with changes in the inflammatory milieu of chronic metabolic disorders rather than with a specific protective or adaptive mechanism. Overall, CatG provides descriptive insight into qualitative aspects of inflammation in long-standing diabetes and warrants further investigation in longitudinal studies.

Anahtar Kelimeler

• Katepsin G
• inflamasyon
• nötrofil proteaz
• tip 2 diyabetes mellitus

Tip 2 Diyabet Mellitus'ta Serum Katepsin G Düzeyleri ve Glisemik ve İnflamatuar Belirteçlerle İlişkisi

Öz

Kathepsin G (CatG), nötrofillerden köken alan bir serin proteaz olup inflamasyon ve vasküler yeniden şekillenme süreçlerine katkıda bulunur. CatG aktivitesindeki düzensizlikler otoimmün ve metabolik hastalıklarla ilişkilendirilmiş olmakla birlikte, tip 2 diyabetes mellitus (T2DM) bağlamındaki rolü yeterince aydınlatılmamıştır. Bu kesitsel çalışmada, 76 T2DM hastası ve 37 sağlıklı kontrolde serum CatG düzeyleri araştırılmıştır. CatG konsantrasyonları ELISA yöntemiyle ölçülmüş; nötrofil/lenfosit oranı (NLR), trombosit/lenfosit oranı (PLR), sistemik immün-inflamasyon indeksi (SII) ve trigliserid/yüksek yoğunluklu lipoprotein kolesterol oranı (TG/HDL) dâhil olmak üzere metabolik ve inflamatuvar indeksler değerlendirilmiştir. Serum CatG düzeyleri T2DM hastalarında kontrollere kıyasla anlamlı derecede daha düşük bulunmuştur (685,6±480,8 vs. 995,4±721,9 pg/mL; p=0,011). Düzeltilmemiş analizlerde T2DM ile CatG düzeyleri arasında negatif bir ilişki saptanmış (B=−309,8; p=0,008); ancak yaş, cinsiyet, bel çevresi ve PLR için düzeltme yapıldıktan sonra bu ilişki istatistiksel anlamlılığını kaybetmiştir (p=0,139). Bu bulgular, gruplar arasındaki ham farkın kısmen temel demografik ve antropometrik dengesizliklerden etkilenmiş olabileceğini düşündürmektedir. Serum CatG düzeyleri HbA1c, açlık plazma glukozu ve bel çevresi ile ters yönde ilişkili bulunurken, inflamatuvar indekslerle anlamlı bir ilişki saptanmamıştır. T2DM’de düşük dereceli inflamasyon yaygın olarak tanımlanmasına karşın, CatG düzeylerinin NLR, PLR veya SII ile paralellik göstermediği görülmüştür. Azalmış serum CatG düzeyleri, belirli bir koruyucu ya da adaptif mekanizmayı yansıtmaktan ziyade, kronik metabolik hastalıklarda gözlenen inflamatuvar ortamla ilişkili değişiklikleri yansıtıyor olabilir. Genel olarak CatG, uzun süreli diyabette inflamasyonun nitel yönlerine ilişkin tanımlayıcı bilgi sağlayabilir ve ileri, uzunlamasına çalışmalarla daha ayrıntılı olarak incelenmeyi gerektirir.

Anahtar Kelimeler

• Cathepsin G
• inflammation
• neutrophil protease
• type 2 diabetes mellitus

Kaynakça

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