Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, Munich, Germany.
Department of Nephrology, Hospital del Mar-IMIM, Barcelona, Spain.
Nephrol Dial Transplant. 2018 Aug 1;33(8):1292-1304. doi: 10.1093/ndt/gfx219.
Curing 'diabetic nephropathy' is considered an unmet medical need of high priority. We propose to question the concept of 'diabetic nephropathy' that implies diabetes as the predominant cause of kidney disease, which may not apply to the majority of type 2 diabetics approaching end-stage kidney disease. With the onset of diabetes, hyperglycaemia/sodium-glucose co-transporter-2-driven glomerular hyperfiltration promotes nephron hypertrophy, which, however, on its own, causes proteinuria not before a decade later, probably because podocyte hypertrophy can usually accommodate an increase in the filtration surface. In contrast, precedent chronic kidney disease (CKD), that is, few nephrons per body mass, e.g. due to poor nephron endowment from birth, obesity, pregnancy, or renal ageing or injury-related nephron loss, usually precedes the onset of type 2 diabetes. This applies in particular in older adults, and each on its own, but especially in combination, further aggravates single nephron hyperfiltration and glomerular hypertrophy. Whenever this additional hyperglycaemia-driven enlargement of the glomerular filtration surface exceeds the capacity of podocytes for hypertrophy, podocytes detachment leads to glomerulosclerosis and nephron loss, i.e. CKD progression. Animal models of 'diabetic nephropathy' based only on hyperglycaemia do not mimic this aspect and therefore poorly predict outcomes of clinical trials usually performed on elderly CKD patients with type 2 diabetes. Thus, we advocate the use of renal mass (nephron) ablation in type 2 diabetic animals to better mimic the pathophysiology of 'CKD with diabetes' in the target patient population and the use of the glomerular filtration rate as a primary endpoint to more reliably predict trial outcomes.
治愈“糖尿病肾病”被认为是高度优先的未满足的医学需求。我们建议对“糖尿病肾病”这一概念提出质疑,因为该概念暗示糖尿病是导致肾脏疾病的主要原因,但这可能不适用于大多数接近终末期肾病的 2 型糖尿病患者。随着糖尿病的发生,高血糖/钠-葡萄糖协同转运蛋白 2 驱动的肾小球高滤过会促进肾小球肥大,然而,仅靠肾小球肥大本身并不会导致蛋白尿,这要在 10 年后才会发生,可能是因为足细胞肥大通常可以适应滤过表面积的增加。相比之下,先前存在的慢性肾脏病(CKD),即每个身体质量单位的肾小球数量较少,例如由于出生时肾小球数量不足、肥胖、妊娠、肾脏老化或与损伤相关的肾小球丢失,通常先于 2 型糖尿病的发生。这尤其适用于老年人,而且每种情况单独发生,但尤其是在组合发生时,会进一步加重单个肾小球的高滤过和肾小球肥大。只要这种额外的高血糖驱动的肾小球滤过表面积的增大超过足细胞肥大的能力,足细胞就会脱落,导致肾小球硬化和肾小球丢失,即 CKD 进展。仅基于高血糖的“糖尿病肾病”动物模型无法模拟这一方面,因此无法很好地预测通常在伴有 2 型糖尿病的老年 CKD 患者中进行的临床试验的结果。因此,我们提倡在 2 型糖尿病动物中使用肾质量(肾小球)消融,以更好地模拟目标患者人群中“糖尿病伴 CKD”的病理生理学,并将肾小球滤过率作为主要终点,以更可靠地预测试验结果。