2 型糖尿病および糖尿病性腎症患者における唾液および血清シスタチン SA 濃度に関する研究

Salivary and serum cystatin SA levels in patients with type 2 diabetes mellitus or diabetic nephropathy.

抄録

目的:

2型糖尿病および糖尿病性腎症のスクリーニングおよび診断に有用と考えられる唾液バイオマーカーを検討する。

OBJECTIVE: To investigate putative salivary biomarkers for screening and diagnosis of type 2 diabetes mellitus and diabetic nephropathy.

デザイン:

2型糖尿病患者29名、糖尿病性腎症患者20名、非糖尿病性腎症患者8名、健常者25名から唾液および血清サンプルを収集した。まず、性・年齢をマッチさせた健常者6名と2型糖尿病患者6名の無刺激唾液サンプルをプールし、二次元ゲル電気泳動後、質量分析を行った。さらに、2型糖尿病患者の唾液中のシスタチンSAのタンパク質発現を、酵素結合免疫吸着法（ELISA）を用いて唾液および血清中で調べた。

DESIGN: Saliva and serum samples were collected from 29 patients with type 2 diabetes, 20 patients with diabetic nephropathy, eight patients with non-diabetic induced nephropathy, and 25 healthy subjects. Initially, pooled unstimulated saliva samples from six sex- and age-matched healthy subjects and six patients with type 2 diabetes were subjected to two-dimensional gel electrophoresis, followed by mass spectrometry. Protein expression of cystatin SA in the saliva of patients with type 2 diabetes was further examined in saliva and serum using enzyme-linked immunosorbent assay (ELISA).

結果:

二次元ゲル電気泳動法により、2型糖尿病患者の唾液中シスタチンSAの発現量が増加していることを明らかにした。ELISA法では、2型糖尿病患者の唾液中シスタチンSA濃度は健常者と比較して弱い上昇傾向を示した。歯周病の状態によって患者を層別化し，年齢，性別，HbA，推定糸球体濾過量（eGFR），歯の本数を調整した線形回帰分析では，唾液中のシスタチンSA濃度とPeriodontal Screening and Recording（PSR）指標（β＝0.297，p＜0.05）が関連することが明らかとなった．血清シスタチンSA値は、年齢、性別、HbA、歯の数、PSR指数で調整した場合、eGFRと負の相関があった（β=-0.534、p< 0.0001）。

RESULTS: Two-dimensional gel electrophoresis revealed upregulation of salivary cystatin SA in patients with type 2 diabetes. ELISA showed a weak trend of increasing salivary cystatin SA levels in patients with type 2 diabetes, compared with those levels in healthy subjects. When patients were stratified according to periodontal status, linear regression analyses revealed that salivary cystatin SA levels were associated with Periodontal Screening and Recording (PSR) index (β = 0.297, p <  0.05) when the analysis was adjusted for age, sex, HbA, estimated glomerular filtration rate (eGFR), and number of teeth. Serum cystatin SA levels were negatively associated with eGFR (β = -0.534, p <  0.0001) when the analysis was adjusted for age, sex, HbA, number of teeth, and PSR index.

結論:

唾液中シスタチン SA は歯周病重症度と関連し，さらに血清中シスタチン SA 濃度は腎機能を反映する可能性が示唆された．

CONCLUSIONS: Salivary cystatin SA was associated with periodontal disease severity; moreover, serum cystatin SA levels could reflect kidney function.