Background and purpose: Population‐based studies suggest that severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) vaccines may trigger immune‐mediated thrombotic thrombocytopenia (VITT) raising concerns for other autoimmune responses. The aim was to characterize neurological autoimmunity after SARS‐CoV‐2 vaccinations.Methods: In this single‐centre prospective case study patients with neurological autoimmunity in temporal association (≤6 weeks) with SARS‐CoV‐2 vaccinations and without other triggers are reported. Clinical, laboratory and imaging data were collected with a median follow‐up of 49 days.Results: In the study period 232,603 inhabitants from the main catchment area of our hospital (Rhein‐Neckar‐Kreis, county) received SARS‐CoV‐2 vaccinations. Twenty‐one cases (new onset n = 17, flares n = 4) diagnosed a median of 11 days (range 3–23) following SARS‐CoV‐2 vaccinations (BNT162b2 n = 12, ChAdOx1 n = 8, mRNA‐1273 n = 1) were identified. Cases included VITT with cerebral venous sinus thrombosis (n = 3), central nervous system demyelinating diseases (n = 8), inflammatory peripheral neuropathies (n = 4), myositis (n = 3), myasthenia (n = 1), limbic encephalitis (n = 1) and giant cell arteritis (n = 1). Patients were predominantly female (ratio 3.2:1) and the median age at diagnosis was 50 years (range 22–86). Therapy included administration of steroids (n = 15), intravenous immunoglobulins in patients with Guillain–Barré syndrome or VITT (n = 4), plasma exchange in cases unresponsive to steroids (n = 3) and anticoagulation in VITT. Outcomes were favourable with partial and complete remissions achieved in 71% and 24%, respectively. Two patients received their second vaccination without further aggravation of autoimmune symptoms under low‐dose immunosuppressants.Conclusions: In this study various neurological autoimmune disorders encountered following SARS‐CoV‐2 vaccinations are characterized. Given the assumed low incidence and mostly favourable outcome of autoimmune responses, the benefits of vaccinations outweigh the comparatively small risks.

Prior epidemiologic studies suggest inverse relations between diabetes and glioma risk, but the underlying mechanisms, including use of antidiabetic drugs, are unknown. We therefore performed a matched case-control analysis using the Clinical Practice Research Datalink (CPRD). We identified incident glioma cases diagnosed between 1995 and 2012 and matched each case with 10 controls on age, gender, calendar time, general practice, and years of active history in the CPRD. We performed conditional logistic regression to estimate odds ratios (ORs) with 95% CIs, adjusted for body mass index and smoking. We identified 2005 cases and 20 050 controls. Diabetes was associated with decreased risk of glioma (OR = 0.74; 95% CI = 0.60–0.93), particularly glioblastoma (OR = 0.69; 95% CI = 0.51–0.94). Glioblastoma risk reduction was markedly pronounced among diabetic men (OR = 0.60; 95% CI = 0.40–0.90), most apparently for those with diabetes of long-term duration (OR for >5 vs 0 y = 0.46; 95% CI = 0.26–0.82) or poor glycemic control (OR for HbA1c ≥8 vs <6.5% = 0.20; 95% CI = 0.06–0.70). In contrast, the effect of diabetes on glioblastoma risk was absent among women (OR = 0.85; 95% CI = 0.53–1.36). No significant associations with glioma were found for use of metformin (OR for ≥30 vs 0 prescriptions = 0.72; 95% CI = 0.38–1.39), sulfonylureas (OR = 0.71; 95% CI = 0.39–1.30), or insulin (OR = 0.79; 95% CI = 0.37–1.69). Antidiabetic treatment appears to be unrelated to glioma, but long-term diabetes duration and increased HbA1c both show decreased glioma risk. Stronger findings in men than women suggest low androgen levels concurrent with diabetes as a biologic mechanism.

Stattic and metformin inhibit brain tumor initiating cells by reducing STAT3-phosphorylation Stattic and metformin inhibit brain tumor initiating cells by reducing STAT3-phosphorylation

To this day, glioblastoma (GBM) remains an incurable brain tumor. Previous research has shown that metformin, an oral anti-diabetic drug, may decrease GBM cell proliferation and migration especially in brain tumor initiating cells (BTICs). As transforming growth factor β 2 (TGF-β₂) has been reported to promote high-grade glioma and is inhibited by metformin in other tumors, we explored whether metformin directly interferes with TGF-β₂-signaling. Functional investigation of proliferation and migration of primary BTICs after treatment with metformin+/−TGF-β₂ revealed that metformin doses as low as 0.01 mM metformin thrice a day were able to inhibit proliferation of susceptible cell lines, whereas migration was impacted only at higher doses. Known cellular mechanisms of metformin, such as increased lactate secretion, reduced oxygen consumption and activated AMPK-signaling, could be confirmed. However, TGF-β₂ and metformin did not act as functional antagonists, but both rather inhibited proliferation and/or migration, if significant effects were present. We did not observe a relevant influence of metformin on TGF-β₂ mRNA expression (qRT-PCR), TGF-β₂ protein expression (ELISA) or SMAD-signaling (Western blot). Therefore, it seems that metformin does not exert its inhibitory effects on GBM BTIC proliferation and migration by altering TGF-β₂-signaling. Nonetheless, as low doses of metformin are able to reduce proliferation of certain GBM cells, further exploration of predictors of BTICs' susceptibility to metformin appears justified.