^99mTC-MIBI Scintigraphy Earlier Lower Extremity Microvascular Perfusion And Taurine Intervention In Diabetic Peripheral Arterial Diseases

Diabetes is one of the most important chronic non-infectious diseases.The incidence of diabetes is increasing year by year.In 2010,the prevalence of diabetes in Chinese adults was 11.6%.Peripheral arterial disease?PAD?is an important complication of diabetes mellitus,a marker of systemic atherosclerosis,and a powerful predictor of cardiovascular disease.According to the specific diagnostic criteria currently used,the prevalence of PAD in people over 70 may be as high as 30%.However,although PAD is common and has serious consequences,it is often undetected and undertreated.Many PAD patients have almost no symptoms and cannot be effectively identified.At present,the detection method of PAD is mainly to evaluate the pathological changes of large vessels.There are some deficiencies in evaluating the extent and extent of tissue blood perfusion,especially in the early stage of diabetes.Therefore,it is necessary to establish an effective method to detect the blood perfusion of lower limb muscles and screen the early pathological changes of PAD.Hill function is a concentration-response function,which can be candidate for simulating tissue and cellular uptake of ^99mTc-MIBI dynamics.This study took a novel Hill function-based analysis of ^99mTc-MIBI scintigraphy data,to evaluate earlier lower extremity perfusion changes in diabetic patients.Early intervention for PAD patients can effectively reduce the incidence of PAD and prevent target organ damage.At present,some strategies for prevention and treatment of PAD have been used to intervene in the early and high-risk groups of PAD,including smoking cessation,exercise,weight loss,and the use of lipid-lowering drugs and antiplatelet drugs.Although these lifestyle interventions and drugs can prevent and treat PAD,poor compliance and side effects of antiplatelet drugs hinder their use in PAD patients.Therefore,there is an urgent need for safe and effective treatment to prevent the progress of PAD.The pathogenesis of PAD is complex.The platelets in diabetic patients are overactive,with increased activation,adhesion and aggregation.Platelet Ca²⁺influx is closely related to platelet function.Classical Transient Receptor Potential Channels?TRPCs?are a class of non-selective cationic channels on cell membranes.TRPC6,a member of TRPC6,has been proved to be up-regulated in diabetic patients and regulates platelet Ca²⁺influx through Inositol-1,4,5-trisphosphate?IP3?pathway.Taurine is one of the conditionally essential amino acids in mammals.Its synthesis is limited,but it can be supplemented from meat products and seafood.Taurine plays an important role in energy metabolism,antioxidation,endothelial cell function,nerve conduction and calcium homeostasis control.It has been found that taurine can promote vasodilation in hypertensive patients and reduce platelet aggregation and activation in diabetic patients.Whether taurine can improve vascular function and reduce platelet activation in diabetic patients remains unclear.Therefore,we further explored earlier lower extremity perfusion changes of PAD,the effect of taurine on vascular function in diabetic patients and the specific mechanism of reducing platelet Ca²⁺influx.Materials and methods:This study is divided into three parts,the first part of the study recruited 88 volunteers?30 healthy controls,34 diabetics and 24 patients with diabetes mellitus and PAD?and used^99mTc-MIBI imaging.In the second part,200 volunteers with type 2 diabetes mellitus,normal blood glucose and abnormal glucose regulation were randomly assigned to taurine group?100 cases?and placebo group?100 cases?.Taurine granules or placebo granules were given for 12 weeks respectively.The third parts of the clinical research program were discussed and approved by the Hospital Ethics Committee of The Third Military Medical University and registered in www.ClinicalTrials.gov with the uniue identifier NCT03410537.All volunteers were fully informed and signed the informed consent.Taurine granules or placebo granules were given for 12 weeks respectively.The third part included 43diabetic volunteers and 45 normal blood glucose volunteers.Diabetic subjects were randomly assigned to taurine group and placebo group for 12 weeks.1.Assessment of lower limb muscle perfusion in patients with diabetes mellitus:Using image analysis equipment,sequence images and time activity curves were created from^99mTc-MIBI imaging data.2.The effect of taurine intervention on blood pressure in diabetic patients.Use mercury sphygmomanometer to measure room blood pressure of volunteers during taurine intervention.3.Effects of taurine on vascular function in patients with diabetes mellitus:Carotid intima-media thickness,pulse wave velocity,endothelium-dependent vasodilation?FMD?and non-endothelium-dependent vasodilation?NMD?were measured before and after taurine intervention with vascular ultrasound and blood pressure pulse wave device.4.The effect of taurine intervention on platelet Ca²⁺in type 2 diabetes mellitus patients.Platelet was extracted from fresh peripheral blood of subjects before and after intervention.The changes of platelet free Ca²⁺were measured by Fura-2 AM/Ca²⁺fluorescence probe technique and fluorescence ratio meter.5.The mechanism of taurine intervention on platelet activation in patients with type 2diabetes mellitus.Platelet protein was extracted from fresh peripheral blood of subjects before and after intervention.The expression of TRPC6,SERCA2,SERCA3,STIM1 and CaMKII was detected by Western Blots.6.Effects of high glucose?25mmol/l?and sodium hydride?NaHS?on the expression of TRPC6,SERCA2,SERCA3,STIM1 and CaMKII in platelets.Result:1.Compared with normal subjects,the maximum ^99mTc-MIBI perfusion count was significantly decreased and the peak time of perfusion was prolonged in diabetic patients.2.Hill function parameters related to microvascular perfusion in lower extremities were in good agreement with the results of ABI and CTA.After lower limb interventional therapy,the parameters of calf muscle perfusion were significantly improved.3.Long-term taurine intervention significantly increased endothelium-dependent vasodilation and non-endothelium-dependent vasodilation in type 2 diabetic patients,but placebo intervention had no such effect.4.Long-term taurine intervention significantly decreased pulse wave velocity and carotid intima-media thickness in patients with type 2 diabetes mellitus,but placebo intervention had no such effect.5.Compared with baseline blood pressure,long-term taurine intervention significantly decreased the blood pressure in the diagnosis room of type 2 diabetes mellitus patients.6.The correlation between baseline plasma taurine level and blood pressure,vascular function and metabolic indicators.After long-term taurine intervention,the level of plasma taurine increased significantly,which was correlated with the decrease of systolic blood pressure,diastolic blood pressure and serum uric acid level.There was no correlation between placebo intervention and placebo intervention.7.The patients with type 2 diabetes mellitus were divided into subgroups according to their blood glucose values?normal blood glucose group and abnormal glucose regulation group?.The results of subgroup analysis showed that the effects of long-term taurine intervention on blood pressure,vascular function,blood pressure,body fat index and uric acid in normal blood glucose group and abnormal glucose regulation group mainly occ urred in the more significant normal blood glucose group and abnormal glucose regulation group.In patients with diabetes mellitus,hypertension and other risk factors,the improvement of taurine was gradually weakened.8.The expressions of TRPC6,SERCA2,TRPC6,SERCA3,STIM1 and CaMKII in platelets of diabetic patients were significantly higher than those of normal subjects.High glucose can up-regulate the expression of TRPC6,SERCA2,SERCA3,STIM1 and CaMKII in normal human platelets in a time-dependent and dose-dependent manner,and the effect of high glucose is time-dependent and dose-dependent.9.Long-term taurine intervention can reduce the expression of TRPC6,STIM1,SERCA2,SERCA3 and CaMKII in platelets of type 2 diabetes mellitus after taurine intervention.NaHS and NaHS can inhibit the increase of TRPC6,SERCA2,SERCA3,STIM1 and CaMKII expression in platelets mediated by high glucose.Conclusion:1.^99mTc-MIBI radionuclide imaging of lower extremity arteries of diabetic patients was performed in large samples at home and abroad.The results showed that the maximum perfusion rate of diabetic patients decreased in the early stage,while the peak time prolonged,suggesting the existence of blood supply disorders suggesting that diabetic patients have lower extremity blood supply disorders.In diabetic patients with lower extremity artery disease,the maximum perfusion rate and peak time were further prolonged.^99mTc-MIBI radionuclide imaging of lower extremity artery was consistent with the degree of lower extremity lesions assessed by ankle-brachial index?ABI?and CT angiography?CTA?,and it could effectively evaluate the efficacy of lower extremity interventional surgery.It provides a standardized diagnostic method for clinical radionuclide ima ging in detecting lower extremity vascular lesions in diabetic patients and evaluating the effect of interventional therapy.2.Long-term taurine intervention can reduce the systolic and diastolic blood pressure in diabetic patients.3.Long-term taurine intervention can significantly improve endothelium-dependent and non-endothelium-dependent vasodilation in type 2 diabetic patients.Long-term taurine intervention can significantly increase plasma taurine and methionine levels.4.High glucose-activated platelet TRPC6 promotes SOCE-mediated platelet Ca2+influx,up-regulates the expression of STIM1,SERCA2,SERCA3 and CaMKII proteins,and promotes platelet activation in diabetic patients.Long-term taurine intervention can inhibit the reduction of platelet Ca2+concentration by TRPC6 in type 2 diabetic patients.