Endocrine Abstracts

Background and aims: Cerebrovascular reactivity (CVR) impairment was reported as a marker of cerebral microangiopathy in long-term type 1 diabetes (DM1). Indices of cerebral blood flow might serve as an indicator of early microangiopathic complications. The aim of this study was to evaluate CVR in patients with DM1 and diabetic nephropathy. Research design and methods: Study has been reviewed by the Local Ethics Committee. The study has been performed in accordance with ethical standards laid down in the Helsinki Declaration. Peak systolic blood flow velocity (S) in the middle cerebral artery (MCA) before (S1) and after (S2) compression of the ipsilateral common carotid artery (CCA) and the index of vasomotor reactivity (VMRr=(S2–S1)×100/S1) were measured with transcranial duplex sonography in 41 patients (age 28.9±6.2 years, duration of DM1 15±4 years, HbA₁c 8.9±1,8%) with DM1, without history of cerebrovascular events, and 22 healthy control subjects (age 26.3±4.2 years). The study included patients with normoalbuminuria AER in the morning urine <20 mg/l (n=22); microalbuminuria AER<199 mg/l (n=12); macroalbuminuria AER ≥200 mg/l (n=7). A decrease of glomerular filtration rate (GFR) of 45–59 ml/min per 1.73 m² was noted in 6 patients, in 35 patients with GFR≥60 ml/min per 1.73 m². Statistical analysis was performed with SPSS 22,0 for Windows, P<0.05.

Results: There was statistically significant decrease of VMRr in patients with DM1 compared with control group (P=0.01) (U-test). S in the MCA before compression of the CCA was not different in the study groups. S had statistically significant decrease after compression in the group of patients with GFR 45–59 ml/min per 1.73 m² compared with the group of patients with GFR≥60 ml/min per 1.73 m² (P=0.008) (U-test). S after compression was higher in patients with macroalbuminuria compared with normoalbuminuria (P=0.019)(P-test). There was not statistically significant difference depending on HbA₁c level, duration of DM1, age, hypertension, smoking, presence and severity of diabetic retinopathy.

Conclusion: The CVR was reduced in patients with DM1. In patients with diabetic nephropathy (macroalbuminuria or GFR<60 ml/min per 1.73 m²), the ability of the MCA to change diameter under the influence of mechanical factor is reduced that leads to a disruption in the ability of the cerebral circulation to compensate a hemodynamic deficit. Diabetic nephropathy can indicate the severity of cerebral microangiopathy in patients with DM1.