從體外數據到真實世界數據探討Canagliflozin 第二型鈉-葡萄糖轉運蛋白-2抑制劑對於肌少症相關表型的影響

Abstract

糖尿病的治療重點對於如何預防其他相關慢性併發症在臨床上也相當被重視。SGLT2抑制劑目前是第二型糖尿病藥物，其藥理機轉透過抑制腎臟近曲小管SGLT2運輸蛋白來降低葡萄糖的再吸收，使葡萄糖經由尿液的排泄量增加。肌少症除了在肌肉功能下降外，同時會伴隨身體活動的減少，使跌倒與骨折的風險增加，進而導致衰弱症的發生。然而現今探討使用SGLT2抑制劑患者與衰弱症或肌少症關係之文獻仍缺乏。因此，本研究目的欲探討使用SGLT2抑制劑的患者是否會增加罹患衰弱症或肌少症的風險。研究方法可分為三部分──細胞實驗、動物實驗，及臺大體系醫療整合資料庫資料作為臨床數據的回溯性世代研究。首先，以C2C12小鼠骨骼肌母細胞在臨床相關濃度下分析canagliflozin對骨骼肌的直接影響作用。我們藉由MTS assay以及trypan blue exclusion assay發現高濃度下的canagliflozin 50μM會抑制骨骼肌細胞增生。接著我們觀察SGLT2抑制劑是否會影響肌肉生成的過程，並發現第五天時處理canagliflozin組別MHC的表現有劑量依賴性的趨勢，進一步發現在臨床濃度下的canagliflozin跟dapagliflozin皆會使 Akt 蛋白表現顯著增加，而不影響 GLUT4及SGLT2的蛋白表現。動物實驗中，我們發現在第二型糖尿病疾病模式BKS.Cg-m +/+ Leprdb /J小鼠以每日管餵 canagliflozin後，OGTT以及PITT實驗中針對曲線下面積葡萄糖總量有顯著差異地下降，顯示canagliflozin主要透過改善葡萄糖的耐受性達到控制血糖的效果，同時發現餵食 8 週後的非糖尿病小鼠握力顯著大於控制組，但疾病用藥組中握力並未改變，顯示SGLT2抑制劑會提升非疾病組別的最大力量，此藥物可以改善疾病組的肌肉表現。藥物並不影響骨骼肌中Akt的表現，對於骨骼肌蛋白主要合成途徑並無顯著的影響，但經由增加磷酸化Foxo3a的表現來調控肌肉降解的相關途徑，顯示canagliflozin會藉由調控轉錄後修飾途徑進而減少骨骼肌萎縮之表現。最後，我們分析國立臺灣大學醫學院附設醫院門診臨床診斷第二型糖尿病且有服用SGLT2抑制劑的患者及對照組，探討其與肌少症及衰弱症之間的關係。我們發現，在糖尿病組別中使用SGLT2抑制劑相較於控制組，發生衰弱前期和骨骼肌相關疾病的風險較高。綜合上述，本篇研究提供臨床上使用SGLT2抑制劑對於骨骼肌影響之藥物安全性的觀點，針對第二型糖尿病患者建議須小心使用 SGLT2 抑制劑。

To date, type II diabetes treatment is important, since it can prevent chronic complications and acute complications, such as hyperosmolar hyperglycemic state. Currently, sodium-glucose cotransporter-2 inhibitors are a new type of drug therapy for type II diabetes. The mechanism of these drugs is to inhibit the reabsorption of filtered sugar and increase renal glucose excretion for blood sugar control. However, there are some controversies and concerns about whether SGLT2 inhibitors would cause sarcopenia or frailty in diabetic patients. Rare research has focused on the effects of SGLT2 inhibitors on skeletal muscle. Therefore, the purpose of this study is to investigate whether patients on SGLT2 inhibitors have an increased risk of sarcopenia or frailty. The methods were divided into three parts: in vitro, in vivo and a retrospective cohort study based on National Taiwan University Hospital-integrated Medical Database .C2C12 mouse skeletal myoblasts and myotubes were used to analyze the direct effect of canagliflozin on skeletal muscle at clinically relevant concentrations. Eight week old male BKS.Cgm+ +/+ Lepr db/J type II diabetic mice and the corresponding nondiabetic mice were fed 30 mg/kg canagliflozin or vehicle by daily oral gavage for eight weeks. We found that there was a significant decrease in the total amount of glucose for the area under the curve, indicating that canagliflozin controls blood sugar by improving glucose tolerance. In terms of muscle strength, canagliflozin increased maximal strength in the nondiabetic mice. In addition, for muscle performance, we found that canagliflozin could improve muscle performance in the diabetic mice. Next, we observed that canagliflozin did not affect the expression of Akt in skeletal muscle but regulated pathways of muscle degradation by increasing the expression of phosphorylated Foxo3a, which reduced the atrophy related transcription factors entering the nucleus. Canagliflozin reduced skeletal muscle atrophy by regulating post-translational modification. Finally, we included diabetic patients from the National Taiwan University Hospital and controls to examine the relationship between SGLT2 inhibitors and sarcopenia and frailty. SGLT2 inhibitors using in the diabetes population was associated with a higher risk of pre-frailty and skeletal muscle-related diseases compared with the control group. In conclusion, our study provided insight into the drug safety of canagliflozin on skeletal muscle. Patients with type II diabetes might use SGLT2 inhibitors with caution due to the concern about sarcopenia-related diseases.