Effect of plant polyphenols on ischemia-reperfusion injury of the isolated rat heart and vessels.

In the present study, we investigated the potential protective effect of selected natural substances in a rat model of heart and mesenteric ischemia-reperfusion (I/R). Experiments were performed on isolated Langendorff-perfused rat hearts, subjected to 30-min global ischemia, followed by 30-min reperfusion. Arbutin, curcumin, rosmarinic acid and extract of Mentha x villosa were applied in the concentration of 1 × 10⁻5 mol/l 10 min before the onset of ischemia and during reperfusion, through the perfusion medium. Mesenteric ischemia was induced by clamping the superior mesenteric artery (SMA) for 60 min, subsequent reperfusion lasted 30 min. Production of reactive oxygen species (ROS) by SMA ex vivo was determined by luminol-enhanced chemiluminiscence (CL). The effect of the substances was tested after their incubation with tissue. Curcumin and extract of Mentha x villosa were found to be the most effective in reducing reperfusion-induced dysrhythmias--ventricular tachycardia and fibrillation. This effect was accompanied by bradycardic effect. The mesenteric I/R induced an increase in CL in vascular tissue which was dampened by substances tested. All substances tested were found to have antioxidant properties, as demonstrated by a reduction in ROS production in mesenteric vessels. This effect was confirmed in curcumin and extract of Mentha x villosa which reduced reperfusion dyshythmias.

Caffeic acid phenethyl ester prevents detrimental effects of remote ischemia-reperfusion injury on healing of colonic anastomoses.

PURPOSE: We aimed to investigate whether caffeic acid phenethyl ester (CAPE) prevents detrimental systemic effects of intestinal ischemia-reperfusion (IR) injury on colonic anastomotic wound healing. METHODS: This experimental study was conducted on 48 male Wistar albino rats. The rats were randomly allocated into four groups and a left colonic anastomosis was performed in all rats: (i) sham-operated group (n = 12), laparatomy without intestinal IR injury; (ii) sham + CAPE group (n = 12), identical to Group 1 except for CAPE treatment (10 µmol/kg, intravenously); (iii) intestinal IR group (n = 12), 60 min of superior mesenteric ischemia followed by reperfusion; and (iv) IR + CAPE-treated group (n = 12) (10 µmol/kg, intravenously, 30 min before the construction of colonic anastomosis). On the postoperative day 7, the rats were subjected to relaparotomy for in vivo measurement of the colonic anastomotic bursting pressure. A colonic segment including the anastomotic site was resected for histopathological evaluation and biochemical analyses. The plasma proinflammatory cytokine levels were measured. Body weight changes were examined. RESULTS: CAPE treatment significantly increased colonic anastomotic bursting pressures, and colonic anastomotic tissue hydroxyproline contents and antioxidant parameters (p < .05), and significantly decreased oxidative stress markers in colonic anastomotic tissues and plasma proinflammatory cytokine levels (p < .05). Histopathological scores were significantly better due to CAPE administration (p < .05). CONCLUSIONS: This study clearly showed that CAPE treatment prevented the delaying effects of remote IR injury on colonic anastomotic wound healing. Further clinical studies are required to determine whether CAPE has a useful role in the enhancement of gastrointestinal anastomotic wound healing during particular surgeries in which IR-induced organ injury occurs.

Changes in superior mesenteric artery blood flow after oral, enteral, and parenteral feeding in humans.

OBJECTIVE: Alterations in splanchnic blood flow cause gut ischemia and may predispose to gut-derived sepsis. Increases in superior mesenteric artery (SMA) blood flow occur follow the oral ingestion of food, but the effects of enteral nutrition (EN) on splanchnic perfusion are poorly defined and those of parenteral nutrition (PN) are unknown in humans. The aim of this study was to investigate changes in SMA flow in healthy controls and patients receiving adjuvant nutrition. DESIGN: Qualitative before-after study. SETTING: Intensive care and general wards at Scarborough Hospital, Scarborough, United Kingdom. PATIENTS: Fourteen healthy volunteers and 20 consecutive hemodynamically stable patients receiving adjuvant nutrition. INTERVENTIONS: Oral, EN, or PN after an overnight fast. MEASUREMENTS AND MAIN RESULTS: Duplex ultrasonography was used to assess SMA flow after an overnight fast. Subjects were then rescanned 3 hrs later after commencement of the appropriate test feed so that postprandial flows could be determined. Of the 20 patients recruited, 10 were receiving EN (120 kcal) and 10 PN (175 kcal). Of the 14 volunteers, three received no feed before their second scan (controls), six received an oral meal (530 kcal), and five received EN (120 kcal). Changes in SMA flow within groups were assessed. The control (fasting) volunteers showed no change between the two scans (p = 1.000). All subjects fed intraluminally demonstrated significant increases in postprandial SMA blood flow. Conversely, all patients fed parenterally showed decreased postprandial SMA flows with a median (interquartile range) fasting SMA flow of 14.5 (4.8-24.8) mL/sec, which decreased to 6.1 (2.4-9.2) mL/sec postprandially (p = 0.013). CONCLUSIONS: Splanchnic flow is modulated by the route of feeding. The clinical significance of these findings requires further investigation as they may be important in the management of the critically ill patient, particularly in those with cardiovascular instability or any patient predisposed to gut ischemia.

Doppler study of splanchnic hemodynamics in Hirschsprung's disease.

BACKGROUND: Doppler studies of splanchnic vessels have demonstrated alteration in blood flow in bowel obstruction and strangulation. The aim of this study was to evaluate hemodynamic changes in celiac artery (CA), superior mesenteric artery (SMA) and inferior mesenteric artery (IMA) using pulsed Doppler sonography (PDS) in Hirschsprung's disease. MATERIAL AND METHODS: Fasting splanchnic flowmetry of CA, SMA, and IMA arteries was performed using PDS preoperatively in 13 patients with Hirschsprung's disease and 13 healthy age- and sex-matched controls. Diagnostic workup for Hirschsprung's disease included a barium enema and a rectal biopsy. A primary transanal pull through was performed if the transition zone was at rectosigmoid or midsigmoid. Doppler studies were repeated on the 1st and 7th postoperative day under similar conditions. Mean flow velocity (V(mean)) and the pulsatility index (PI) of the three major vessels was measured. RESULTS: Patients with Hirschsprung's disease showed increased blood flow velocities in CA, SMA, and IMA (p < 0.001), an increased resistance to blood flow in IMA (p < 0.001) and a decreased resistance to blood flow in CA and SMA (p < 0.005 and p < 0.001, respectively). The blood flow velocity for IMA normalized after resection of the aganglionic segment (r = 0.41, p < 0.005, 95% CI: 45.4-52.7). CONCLUSIONS: Hirschsprung's diseaseis associated with alterations in splanchnic vessel hemodynamics which are reversible after corrective surgery. Doppler studies may play an important role in the assessment of bowel function after surgery.

Changes in mesenteric blood flow response to feeding: conventional versus fiber-optic phototherapy.

OBJECTIVE: To evaluate whether fiberoptic phototherapy influences the postprandial increase in mesenteric blood flow velocity similarly to conventional phototherapy in preterm infants. PATIENTS AND METHODS: With the use of Doppler color ultrasonography, blood flow velocity in the superior mesenteric artery was measured both preprandially and postprandially in 19 preterm infants during and after conventional phototherapy, and in 20 preterm infants during and after fiber-optic phototherapy. The mean arterial blood pressure/mean flow velocity ratio was calculated as an estimate of relative vascular resistance of the superior mesenteric artery. RESULTS: The study shows that conventional phototherapy blunts the postprandial mesenteric blood flow response to feeding in preterm infants. Furthermore, it shows that the postprandial increase in intestinal blood flow is not attenuated when fiber-optic phototherapy is administered, and that such postprandial increase of blood flow is significantly greater than in infants receiving conventional phototherapy. During and after fiber-optic phototherapy, a significant reduction in postprandial relative vascular resistance was found; such reduction was significantly greater than during conventional phototherapy. CONCLUSIONS: Fiber-optic phototherapy is preferable to conventional phototherapy for the treatment of hyperbilirubinemia in preterm infants because it does not affect the physiologic postprandial redistribution of blood flow from the periphery to the gastrointestinal system as does conventional phototherapy.