目前,几13基于使用在肝脏内选择性代谢的标记底物的C呼气试验可用于无创评估肝细胞功能。在用于定量评估肝功能的各种底物中13麦撒西丁呼气试验(MBT)已证明是最有希望的[
6-
8]。13麦撒西丁,非那西丁的衍生物,经历O-去甲基化通过肝混合氧化酶系统对乙酰氨基酚和二氧化碳。与其他相比13c标记的底物,甲氧西丁代谢更快,迅速从血流中清除,安全,廉价[
9]。多项研究表明,MBT可靠地区分了健康对照者和已确定的肝硬化患者[
6,
10-
12]。然而,单独区分肝硬化患者和非肝硬化患者的价值有限,因为这可以通过常规临床方法可靠地进行。一种评估非肝硬化患者肝脏疾病进展的无创工具。,from chronic inflammation to fibrosis) and cirrhotic (from Child-Pugh grade A to C) patients would have greater utility in routine clinical practice. At present, many of the treatment/management algorithms for diseases such as the chronic viral hepatitis and nonalcoholic fatty liver disease require the confirmation of fibrosis/cirrhosis for either initiation or modification of therapy [
13,
14]。迄今为止,在各种档次的不同病因的慢性肝脏疾病的区分上MBT其精度有限的信息。
13C-MBT在禁食至少8小时后进行。基线呼吸样本被取来评估量13C存在在基线(国际标准比率= 0.1%)。的patients were then given 75 mg of13C Methacetin (99%13C, Cambridge Isotope Laboratories, Andover, Mass, USA) dissolved in 50 ml of tea to drink. Breath samples were obtained by slow expiration through a tube into a breath sample bag, after a deep inspiration. Breath samples were collected at ten-minute intervals for the first hour and at twenty-minute intervals for up to 120 minutes after substrate administration. All subjects were required to be at rest and without drinking and eating for the duration of the test. The 13CO2/12CO2 isotope ratio in the breath samples was analyzed by nondispersive isotope-selective infrared spectrometry (Wagner Analysentechnik, Bremen, Germany) [
16]。的
δ获得的值与所述基线
δ值。的百分比13计算呼出的C,假设CO2产生速率为5 mmol/min m2。将结果表示为施用剂量的累积百分比(%)13C恢复随着时间的推移,其对应于所施用的剂量13每小时C。
Mean cumulative recovery percentages (metabolic capacity) at both 40 and 120 minutes were compared between patients with various stages of liver disease (Table
2)。At 40 minutes of metabolic capacity, MBT values were significantly lower in patients with cirrhosis compared to those without (
0.25
±
0.22与
0.77
±
0.19,
P
<
。
0001)。MBT值分别为肝硬化的各个等级之间显著不同(表
2)。然而,在肝硬化的患者(
ñ
=
30.),在MBT值无差异显著具有和不具有纤维化例(间,注意到
0.72
±
0.17相对于0。80±0。25,
P
=
。
33)。对于120分钟的累积恢复百分比获得了类似的结果(表
2)。
累积氧化率的平均值13慢性肝病不同阶段的C-MBT在40和120分钟。
肝病阶段
ñ
射精。40 mins一个
平均差异(95% CI)
P
和120分钟。b
平均差异(95% CI)
P
纤维化
21
0.72±0.17
-0.07
.33
0.85±0.14
-0.09
厚
Nonfibrosis /炎症
9
0.80±0.25
(-0.24至0.08)
0.94±0.19
(−0.22到0.03)
硬化
47
0.25±0.22
−0.51
<。
0.43±0.26
−0.47
<。
Noncirrhosis
30.
0.77±0.19
(−0.61−0.41)
0.89±0.15
(-0.57 -0.36到)
注册会计师*肝硬化
12
0.45±0.18
−0.31
<。
0.64±0.19
−0.25
<。
noncirrhosis
29
0.76±1.89
(−0.44−0.18)
0.89±0.15
(-0.36 -0.13到)
CPB#肝硬化
15
0.26±0.17
−0.41
<。
0.46±0.23
−0.36
<。
注册会计师/ noncirrhosis
41
0.67±0.23
(−0.54−0.28)
0.82±0.20
(−0.49−0.24)
CPC* *肝硬化
21
0.12±0.19
−0.44
<。
0.28±0.22
−0.45
<。
非中共肝硬化
56
0.56±0.28
(−0.57−0.30)
0.72±0.26
(−0.57−0.31)
*儿童,#Child-Pugh分级B,和** Child-Pugh分级C.
一个正常范围:0.90 - -1.20。
b正常范围:0.80-1.10。
Discriminatory ability of the MBT was assessed based on the 40 minute cumulative recovery percentages (Table
3)。MBT能够很好地区分有无肝硬化患者(AUC 0.91, 95% CI = 0.82-0.99)和Child-Pugh C肝硬化患者(AUC 0.91, 95% CI = 0.82-0.99),如图所示
1。但对Child-Pugh A (AUC 0.47)的鉴别能力较差,对Child-Pugh B (AUC 0.69)和肝纤维化(AUC 0.67)的鉴别能力较差。后者如图所示
2。