Dexmedetomidine protects against acute kidney injury through downregulating inflammatory reactions in endotoxemia rats

Approximately 42% of patients with sepsis undergo acute kidney injury (AKI), which evidently influences patient survival. However, effective therapy strategies are lacking, thus, the present study investigated the protective effects of dexmedetomidine (DEX), a highly selective α-2 adrenoceptor agonist, in rat sepsis models. Rat sepsis models were generated through lipopolysaccharide injection (LPS; 5 mg/kg) in the tail vein. Rats were pretreated with DEX (10 µg/kg) 10 min before LPS injection to observe its protective effects. Of note, a unique α-2-adrenergic receptor antagonist, yohimbine (YOH; 1 mg/kg, intraperitoneally), was also used to antagonize the protective effects of DEX 30 min before DEX exposure. Thirty-two male Sprague Dawley rats were randomly divided into the Sham, LPS, DEX + LPS and YOH + DEX + LPS groups (n=8/group). All the rats were sacrificed 4 h later to observe the pathological changes of renal tissue, including plasma creatinine (Cr), blood urea nitrogen (BUN), kidney injury molecule-1 (KIM-1) and high mobility group protein 1 (HMGB-1) expression. Interleukin 6 (IL-6), IL-18 and tumor necrosis factor α (TNF-α) were all determined to examine the mechanisms of LPS-induced AKI relative to inflammatory reaction. The results indicated that AKI induced by LPS was serious. Renal pathological injury, plasma Cr, BUN, IL-6, IL-18 and TNF-α were all evidently increased in varying degrees. KIM-1 and HMGB-1 expression was upregulated in the LPS group (P<0.05 vs. Sham group). However, when rats were pretreated with DEX, AKI induced by LPS was decreased significantly. Renal pathological injury, plasma Cr, BUN, IL-6, IL-18, TNF-α, and KIM-1 and HMGB-1 expression were all reduced (P<0.05 vs. LPS group). In addition, exposure of the α-2-adrenergic receptor antagonist, YOH, eliminated this reduction. In conclusion, DEX protected against sepsis-induced AKI through depressing the inflammatory reaction, mechanisms of which may be associated with α-2 receptors inhibition.

Variants of ADRA2A are associated with fasting glucose, blood pressure, body mass index and type 2 diabetes risk: meta-analysis of four prospective studies

AIMS/HYPOTHESIS

We quantified the effect of ADRA2A (encoding α-2 adrenergic receptor) variants on metabolic traits and type 2 diabetes risk, as reported in four studies.

METHODS

Genotype data for ADRA2A single nucleotide polymorphisms (SNPs) rs553668 and rs10885122 were analysed in >17,000 individuals (1,307 type 2 diabetes cases) with regard to metabolic traits and type 2 diabetes risk. Two studies (n = 9,437), genotyped using the Human Cardiovascular Disease BeadChip, provided 12 additional ADRA2A SNPs.

RESULTS

Rs553668 was associated with per allele effects on fasting glucose (0.03 mmol/l, p = 0.016) and type 2 diabetes risk (OR 1.17, 95% CI 1.04-1.31; p = 0.01). No significant association was observed with rs10885122. Of the 12 SNPs, several showed associations with metabolic traits. Overall, after variable selection, rs553668 was associated with type 2 diabetes risk (OR 1.38, 95% CI 1.09-1.73; p = 0.007). rs553668 (per allele difference 0.036 mmol/l, 95% CI 0.008-0.065) and rs17186196 (per allele difference 0.066 mmol/l, 95% CI 0.017-0.115) were independently associated with fasting glucose, and rs17186196 with fasting insulin and HOMA of insulin resistance (4.3%, 95% CI 0.6-8.1 and 4.9%, 95% CI 1.0-9.0, respectively, per allele). Per-allele effects of rs491589 on systolic and diastolic blood pressure were 1.19 mmHg (95% CI 0.43-1.95) and 0.61 mmHg (95% CI 0.11-1.10), respectively, and those of rs36022820 on BMI 0.58 kg/m(2) (95% CI 0.15-1.02).

CONCLUSIONS/INTERPRETATION

Multiple ADRA2A SNPs are associated with metabolic traits, blood pressure and type 2 diabetes risk. The α-2 adrenergic receptor should be revisited as a therapeutic target for reduction of the adverse consequences of metabolic trait disorders and type 2 diabetes.