The effect of spermidine on autoimmunity and beta cell function in NOD mice

Spermidine is a natural polyamine which was shown to prolong lifespan of organisms and to improve cardiac and cognitive function. Spermidine was also reported to reduce inflammation and modulate T-cells. Autophagy is one of the mechanisms that spermidine exerts its effect. Autophagy is vital for β-cell homeostasis and autophagy deficiency was reported to lead to exacerbated diabetes in mice. The effect of spermidine in type 1 diabetes pathogenesis remains to be elucidated. Therefore, we examined the effect of spermidine treatment in non-obese diabetic (NOD) mice, a mouse model for type 1 diabetes. NOD mice were given untreated or spermidine-treated water ad libitum from 4 weeks of age until diabetes onset or 35 weeks of age. We found that treatment with 10 mM spermidine led to higher diabetes incidence in NOD mice despite unchanged pancreatic insulitis. Spermidine modulated tissue polyamine levels and elevated signs of autophagy in pancreas. Spermidine led to increased proportion of pro-inflammatory T-cells in pancreatic lymph nodes (pLN) in diabetic mice. Spermidine elevated the proportion of regulatory T-cells in early onset mice, whereas it reduced the proportion of regulatory T-cells in late onset mice. In summary spermidine treatment led to higher diabetes incidence and elevated proportion of T-cells in pLN.

Asymptomatic cervical artery stenoses in Moscow

The risk of stroke related to asymptomatic carotid artery stenosis is known to be increased in high-grade or rapidly progressive stenosis. Information of the prevalence in the general population is required for the recommendation of screening methods to detect patients needing prophylactic treatment. We studied the prevalence and the grade of severity of extracranial carotid and vertebral artery obstructions by means of Doppler sonography in 529 asymptomatic Russians (m: 343, f: 186; 36-84 years, mean: 58.4 years) living in Moscow city. Internal carotid artery obstructions of more than 50% stenosis were present in 22 (= 4.2%) subjects, 8 of them (1.5%) had bilateral lesions. Appropriate abnormal findings in vertebral arteries were found in 11 (= 2.1%) subjects, in 1 of them bilaterally. Affection of both the carotid and the vertebral arteries was noted in 4(= 0.8%) individuals. There were no sexual differences. The risk factor which correlated most significantly with cervical arterial lesions was hypertension. Carotid lesions were also significantly associated with age and smoking, but not with diabetes or hyperlipoproteinemia. The prevalence of cervical artery stenoses was found to be lower than in western reports, which may be due to different technical equipment and different study design.

Cerebrovascular CO2 reactivity in migraine: assessment by transcranial Doppler ultrasound

Cerebrovascular reactivity to CO2 inhalation was studied by transcranial Doppler sonography in 30 patients with classic or common migraine and 39 healthy controls without clinical or ultrasonic signs of arteriosclerosis. Systolic and diastolic Doppler frequencies of the middle cerebral artery were plotted against end-tidal CO2 partial pressure; the reactivity index (I x R) was defined as relative frequency change during a PCO2 increase of 5 mmHg. In the normal subjects, I x R was 20.0 +/- 6.3 for systolic velocities, and 26.0 +/- 8.2 for diastolic values. Migraineurs during their headache-free interval had significantly higher I x R values on the affected side (mean: 41.6 systolic, 61.2 diastolic), compared with either controls (P less than 0.01) or the contralateral side (mean: 28.3 systolic, 30.8 diastolic; P less than 0.01). During the headache attack, CO2 reactivity was significantly lower than normal only for systolic velocities (mean: 8.3; P less than 0.05). Increased CO2 reactivity is thought to be one phenomenon of migraine. Transcranial Doppler CO2 testing of cerebrovascular reactivity is a reliable method that may be of interest for the diagnostic evaluation and management of migraine patients.