Background and Aim. The impact of Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition on glycemic indices in diabetes mellitus remains far from clear. We explored the effects of PCSK9 inhibition on glycemic indices in the diabetes rat model. Methods. To prepare the anti-PCSK9 vaccine, a peptide construct called Immunogenic Fused PCSK9-Tetanus (IFPT) was linked to the surface of nanoliposome carriers. Healthy rats received four subcutaneous injections of the vaccine at biweekly intervals. Two weeks after the last vaccination, anti-PCSK9 antibody titers, PCSK9 targeting, and inhibition of PCSK9–low-density lipoprotein receptor (LDLR) interaction were evaluated. After verification of antibody generation, the immunized rats were intraperitoneally treated with a single dose (45 mg/kg) of streptozotocin (STZ) to induce diabetes mellitus. The levels of fasting blood glucose (FBG) were measured, and the oral glucose tolerance test (OGTT) as well as the insulin tolerance test (ITT) were carried out to assess glycemic status. At the end of the study, the total cholesterol, low-density lipoprotein cholesterol (LDL-C), triglyceride, and high-density lipoprotein cholesterol concentrations were assayed. Histopathology examination of the liver and pancreas was also performed using the hematoxylin-eosin staining method. Results. The prepared nanoliposomal vaccine could strongly induce anti-PCSK9 antibodies in the vaccinated rats. Within one week following the STZ injection, the FBG level was lower in the vaccinated group vs. diabetic control group (49% (, )). In the OGTT, the injected rats showed improved glucose tolerance as reflected by the reduction of blood glucose levels over 180 min, compared with the diabetic controls. Moreover, the ITT demonstrated that, after the insulin injection, blood glucose concentration declined by 49.3% in the vaccinated group vs. diabetic control group. Expectedly, the vaccinated rats exhibited lower (-26.65%, ) plasma LDL-C levels compared with the diabetic controls. Histopathology examination of pancreas tissue demonstrated that the pancreatic islets of the vaccinated rats had a slight decline in the population of β-cells and few α-cells. Normal liver histology was also observed in the vaccinated rats. Conclusion. PCSK9 inhibition through the liposomal IFPT vaccine can improve the glucose and insulin tolerance impairments as well as the lipid profile in diabetes.

中文翻译：

---

PCSK9 免疫对糖尿病大鼠血糖指数的影响

背景和目的。前蛋白转化酶枯草杆菌蛋白酶/kexin 9 型 (PCSK9) 抑制对糖尿病血糖指数的影响仍远未明确。我们探讨了 PCSK9 抑制对糖尿病大鼠模型中血糖指数的影响。方法. 为了制备抗 PCSK9 疫苗，将一种称为免疫原性融合 PCSK9-破伤风 (IFPT) 的肽构建体连接到纳米脂质体载体的表面。健康大鼠每两周接受四次皮下注射疫苗。最后一次接种疫苗两周后，评估了抗 PCSK9 抗体滴度、PCSK9 靶向和 PCSK9-低密度脂蛋白受体 (LDLR) 相互作用的抑制。在验证抗体产生后，将免疫大鼠腹膜内注射单剂量（45 mg/kg）链脲佐菌素（STZ）以诱导糖尿病。测量空腹血糖（FBG）水平，并进行口服葡萄糖耐量试验（OGTT）和胰岛素耐量试验（ITT）评估血糖状态。在研究结束时，总胆固醇、测定了低密度脂蛋白胆固醇 (LDL-C)、甘油三酯和高密度脂蛋白胆固醇浓度。还使用苏木精-伊红染色法对肝脏和胰腺进行组织病理学检查。结果。制备的纳米脂质体疫苗可以在接种疫苗的大鼠体内强烈诱导抗 PCSK9 抗体。STZ 注射后 1 周内，接种组的 FBG 水平低于糖尿病对照组（49%（, ））。在 OGTT 中，与糖尿病对照组相比，注射的大鼠显示出改善的葡萄糖耐量，这反映在 180 分钟内血糖水平的降低。此外，ITT 表明，注射胰岛素后，接种组的血糖浓度与糖尿病对照组相比下降了 49.3%。预期，接种疫苗的大鼠表现出较低（-26.65%，)血浆 LDL-C 水平与糖尿病对照组相比。胰腺组织的组织病理学检查表明，接种疫苗的大鼠胰岛的β细胞数量略有下降， α细胞数量很少。在接种疫苗的大鼠中也观察到正常的肝脏组织学。结论。通过脂质体 IFPT 疫苗抑制 PCSK9 可以改善糖尿病患者的葡萄糖和胰岛素耐受性损伤以及血脂谱。