Diabetes mellitus or Type 2 diabetes (T2D) is a metabolic disorder characterized by chronic hyperglycaemia . Dermatological complications are common in diabetic subjects, with about 30% of patients experiencing cutaneous involvement such as acanthosis nigricans, necrobiosis lipoidica, diabetic dermopathy, etc. . These complications could be a result of hyperglycaemia and decreased insulin or could be associated with specific chronic complications of the disease as well as antidiabetic drugs treatment or secondary endocrine and metabolic disorders [2, 3]. The disturbed epidermal barrier function in diabetic subjects frequently increases the susceptibility to bacterial and fungal infections, which could occur less frequently in healthy people. Specific skin disorders such as necrobiosis lipoidica diabeticorum, scleroderma adultorum, acanthosis nigricans, are the result of diabetic vasculopathy and neuropathy .
Higher perceived age on the face has also been associated with high serum glucose levels . High levels of glucose in diabetes can react by nonenzymatic Maillard reactions with proteins to form unstable, highly reactive proteins with carbohydrate adduct [5, 6]. These products are termed advanced glycation end products (AGEs) and are known to crosslink collagen .
Although the AGEs formation is associated with normal ageing , their progression may be accelerated in diabetic subjects because of their elevated blood sugar [8, 9]. Furthermore, excessive AGEs are associated with the pathogenesis of microvascular and macrovascular complications, which affect organs in the nervous system, the heart, the kidneys, and small blood vessels .
Several studies have demonstrated that elevated skin autofluorescence (SAF) reflects skin AGEs and can be used as biomarkers of diabetes [11, 12, 13, 14]. Additionally, SAF highly correlates with diabetic complications, and it is a predictive factor for diabetic retinopathy and nephropathy [13, 14, 15]. Both SAF and loss of skin elasticity increase with age, suggesting an implication of AGEs in the cutaneous alterations observed with ageing . However, the direct contribution of glycation to the loss of skin elasticity is not yet clearly demonstrated.
In China, with the rapid economic growth and urbanization, lifestyle changed significantly. Over the past 40 years, the prevalence of diabetes in China has increased from less than 1 to 12.8% in 2018, and the prevalence of prediabetes is 35.2%, making it the country with the largest number of diabetes cases in the world . Additionally, the national survey in China also showed that a large proportion of diabetes was undiagnosed and that patients with newly diagnosed diabetes accounted for 60% of the total diabetic population . Consequently, it is striking that diabetic nephropathy among those with T2D has become one of the most important public health crises in China, and there is an urgent need to assess the epidemiological characteristics and risk factors of diabetic nephropathy in T2D in China to implement effective interventions .
Having specific and simpler methods such as SAF will be useful in measuring AGEs formation and its rapid progression due to elevated blood sugar levels in diabetic subjects to prevent further microvascular and macrovascular complications.
This is a report of the findings from a study, regarding the potential influence of T2D in dermatological complications and skin ageing associated with AGEs determined by SAF in a Chinese population.