Secretion of salivary statherin is compromised in uncontrolled diabetic patients

• A major salivary protein, statherin, was evaluated in diabetic and healthy subjects.
• Statherin levels in parotid saliva (PS) were reduced in type 2 diabetics.
• PS statherin levels were negatively correlated with HbA1c & fasting glucose levels.
• Diabetic patients have higher decayed, missing, and filled teeth (DMFT) scores.
• This is the first study to show decreased statherin in saliva of type 2 diabetics.

BackgroundStatherin is an important salivary protein for maintaining oral health. The purpose of the current study was to determine if differences in statherin levels exist between diabetic and healthy subjects.MethodsA total of 48 diabetic and healthy controls were randomly selected from a community-based database. Diabetic subjects (n = 24) had fasting glucose levels > 180 mg/dL, while controls (n = 24) had levels < 110 mg/dL. Parotid saliva (PS) and sublingual/submandibular saliva (SS) were collected and salivary flow rates determined. Salivary statherin levels were determined by densitometry of Western blots. Blood hemoglobin A1c (HbA1c) and total protein in saliva were also obtained.ResultsSS, but not PS, salivary flow rate and total protein in diabetics were significantly less than those in healthy controls (p = 0.021 & p < 0.001 respectively). Correlation analysis revealed the existence of a negative correlation between PS statherin levels and HbA1c (p = 0.012) and fasting glucose (p = 0.021) levels, while no such correlation was found for SS statherin levels. When statherin levels were normalized to total salivary protein, the proportion of PS statherin, but not SS statherin, in diabetics was significantly less than that in controls (p = 0.032). In contrast, the amount of statherin secretion in SS, but not PS, was significantly decreased in diabetics compared to controls (p = 0.016).Conclusions and general significanceThe results show that synthesis and secretion of statherin is reduced in diabetics and this reduction is salivary gland specific. As compromised salivary statherin secretion leads to increased oral health risk, this study indicates that routine oral health assessment of these patients is warranted.