Alcohol dehydrogenase: a potential new marker for diagnosis of intestinal ischemia using rat as a model

Abstract

Aim: Intestinal ischemia (Ii) is an abdominal emergency due to blockade of the superior mesenteric artery resulting in 60-100% mortality if diagnosed late. Changes in several biochemical parameters such as D (-)-lactate, Creatinine kinase isoenzymes and lactate dehydrogenase suggested for early diagnosis, lack specificity and sensitivity. Therefore a biochemical parameter with greater sensitivity needs to be identified.

Methods: Wistar male rats were randomly assigned into two groups; control sham operated (n = 24) and ischemic test (n = 24) group. Superior mesenteric arterial occlusion was performed in the ischemic test group for 1 h. Alcohol dehydrogenase (ADH) was estimated in blood from portal vein, right ventricle of heart, dorsal aorta (DA) and inferior vena cava (IVC). The Serum glutamic acid pyruvate transaminase (SGPT) was also estimated in blood from portal vein and right ventricle of heart.

Results: A significant increase (P<0.001) in the levels of ADH in both portal blood as well as heart blood of the test group (232.72+/-99.45 EU and 250.85+/-95.14 EU, respectively) as compared to the control group (46.39+/-21.69 EU and 65.38+/-30.55 EU, respectively) were observed. Similarly, increased levels of ADH were observed in blood samples withdrawn from DA and IVC in test animals (319.52+/-80.14 EU and 363.90+/-120.68 EU, respectively) as compared to the control group (67.68+/-63.22 EU and 72.50+/-58.45 EU, respectively). However, in test animals there was significant increase in SGPT in portal blood (P = 0.054) without much increase in heart blood.

Conclusion: Significant increase in the levels of ADH in portal and heart blood within 1 h of SMA occlusion without increase in SGPT in heart blood, suggests that the origin of ADH is from ischemic intestine and not from liver. Similarly, raised ADH levels were found in DA and IVC as well. IVC blood does represent peripheral blood sample. A raised level of ADH in test animals confirms it to be a potential marker in the early diagnosis of Ii.

Figure 1

Alcohol Dehydrogenase Assay By Skursky et al (A) and SGPT Assay (B) performed in heart blood and portal blood of 1 h ischemic test and sham operated control group. A: Alcohol dehydrogenase assay performed by Skursky et al method. CH and TH represent the blood withdrawn from heart of control group and test group, respectively. CP and TP represent the blood withdrawn from portal vein of control group and test group, respectively. DAC and DAT represent the dorsal aorta blood sample from control and test group, respectively while IVCC and IVCT represent the blood sample from inferior vena cava of control and test group, respectively. The EU expressed in terms of micromoles of NDMA reduced per min/L of serum; B: SGPT assay. CH and TH represent the blood withdrawn from heart of control group and 1 h ischemic test group, respectively. CP and TP represent the blood withdrawn from portal vein of control group and 1 h ischemic test group, respectively.

Figure 2

Kinetic assay of Alcohol dehydrogenase from serum carried out at 30 °C. (B) Showing practically no auto-reduction of NDMA in the absence of serum, (C) reduction of NDMA in the presence of serum drawn from the heart of control animal after 1 h of sham operation, (T) reduction of NDMA in presence of serum drawn from the heart of test animal after 1 h SMA occlusion.

Figure 3

Histology of intestine from rats. A: C- control sham operated group; 0 grade injury i.e. no damage to villi and crypts; B: t-test one-hour intestinal ischemic group; Total villous loss with some crypts involved; stroma normal. Vessels are patent (i.e. grade 3 injury).