University of Guilan Caspian Journal of Environmental Sciences 1735-3033 24 2 2026 04 01 Morphological and histopathological features of distal tissue damage in diabetes mellitus 607 614 9638 10.22124/cjes.2026.9638 EN Raissa Utegaiyeva Department of Biology, Kazakh National Women׳s Pedagogical University, Almaty, Kazakhstan Raigul Shaikhynbekova Department of Normal Physiology with a course in Biophysics, Asfendiyarov Kazakh National Medical University, Almaty, Kazakhstan Zina Tungushbaeva Head of the Department of Molecular Biology, Kazakh-Russian Medical University, Almaty, Kazakhstan Gulnara Tashenova Department of Biology, Faculty of Natural Sciences and Geography, Abai Kazakh National Pedagogical University, Almaty, Kazakhstan Tolkyn Ukusheva Zhetysu University named after I.Zhansugurov, Taldykorgan, Kazakhstan Ainur Atabayeva Zhetysu University named after I.Zhansugurov, Taldykorgan, Kazakhstan Sarzhan Sharipova Department of Toxicological Chemistry, Asfendiyarov Kazakh National Medical University, Almaty, Kazakhstan Serik Abdreshov Laboratory of Physiology Lymphatic System, Institute of Genetics and Physiology SC MSHE RK and Kazakh National University, al -Farabi, Almaty, Kazakhstan Journal Article 2026 05 25 Diabetes mellitus frequently damages distal tissues, particularly in the lower limbs, yet the morphological and histopathological features of this damage have not been systematically described in the Kazakh population. To address this gap, we examined 47 distal tissue specimens collected between February and September 2025 from diabetic patients in Almaty and Astana, Kazakhstan. The specimens came from two sources: 34 surgical samples (debridement or amputation for foot ulcers or gangrene) and 13 post‑mortem biopsies from diabetic patients without active foot infection. Standard histological processing with H & E, PAS, Masson’s trichrome, and S‑100 stains was performed. Almost all specimens (95.7%) showed capillary basement membrane thickening, which was severe in 42.6% of cases. Perineural fibrosis occurred in 74.5% and nerve fibre loss in 78.7%. Epidermal thinning averaged 52.3 µm, well below the normal range, accompanied by hyperkeratosis (74.5%) and loss of rete ridges (80.9%). Surgical patients had significantly more severe changes than autopsy patients, especially in perineural fibrosis (grade 1.62 vs. 0.77, p < 0.001) and capillary thickening (grade 2.41 vs. 1.46, p < 0.001). Higher HbA1c correlated strongly with more severe capillary thickening (Spearman ρ = 0.62, p < 0.001), epidermal thinning (ρ = -0.48, p = 0.001), and perineural fibrosis (ρ = 0.54, p < 0.001). Over half of the patients (55.3%) had the complete triad of epidermal, vascular, and neural damage. These findings demonstrate that diabetic distal tissue pathology in Kazakhstan follows a progressive, HbA1c‑dependent pattern affecting multiple tissue compartments simultaneously. The histological severity gradient between surgical and autopsy groups suggests that microvascular and neural damage precedes clinical ulceration. Routine histopathological assessment of distal tissue could help identify high‑risk patients earlier and guide preventive strategies.

https://cjes.guilan.ac.ir/article_9638_d241ee05fcc2c5521c6f4489d8a786ec.pdf