Confocal laser endomicroscopy reliably detects sepsis-related and treatment-associated changes in intestinal mucosal microcirculation

Dl-3-n-butylphthalide improves intestinal microcirculation disorders in septic rats by regulating the PI3K/AKT signaling pathway and autophagy

PURPOSE

Sepsis has complex pathophysiological mechanisms that bring new challenges in the treatment of sepsis at a time when the intestinal microcirculation in sepsis is receiving increasing attention. Dl-3-n-butylphthalide (NBP), which is a drug that can improve multiorgan ischemic diseases, is also worth examining to improve the intestinal microcirculation in sepsis.

METHODS

In this study, male Sprague-Dawley rats were divided into the sham group (n = 6), CLP group (n = 6), NBP group (n = 6) and NBP + LY294002 group (n = 6). The rat model of severe sepsis was established by cecal ligation and puncture (CLP). Abdominal wall incisions and sutures were performed in the first group, and CLP was performed in the latter three groups. Normal saline/NBP/NBP + LY294002 solution was injected intraperitoneally 2 h or 1 h before modeling. Hemodynamic data (blood pressure and heart rate) were recorded at 0, 2, 4 and 6 h. Sidestream dark field (SDF) imaging and the Medsoft System were used to observe the intestinal microcirculation of rats and obtain data at 0, 2, 4, and 6 h. Six hours after the model was established, the serum levels of TNF-α and IL-6 were measured to evaluate the level of systemic inflammation. Pathological damage to the small intestine was evaluated by electron microscopy and histological analysis. The expression levels of P-PI3K, PI3K, P-AKT, AKT, LC3 and p62 in the small intestine were analyzed by Western blotting. The expressions of P-PI3K, P-AKT, LC3 and P62 in small intestine were detected by immunohistochemical staining.

RESULTS

NBP improved intestinal microcirculation disturbances in septic rats, alleviated the systemic inflammatory response, reduced the destruction of the small intestinal mucosa and the disruption of microvascular endothelial cells, and alleviated autophagy in vascular endothelial cells. NBP increased the ratio of P-PI3K/total PI3K, P-AKT/total AKT, and P62/β-actin and decreased the ratio of LC3 II/LC3 I.

CONCLUSION

NBP ameliorated intestinal microcirculation disturbances and the destruction of small intestinal vascular endothelial cells in septic rats by activating the PI3K/Akt signaling pathway and regulating autophagy.

In vivo real-time assessment of the anastomotic blood supply in colorectal surgery using confocal laser endomicroscopy in an anastomotic model

BACKGROUND AND STUDY AIMS

Anastomotic ischemia can affect healing and eventually lead to anastomotic leakage, and confocal laser endomicroscopy (CLE) can offer detailed observations at the subcellular level. We aimed to evaluate the anastomotic microcirculation in different anastomotic perfusion models using CLE.

METHODS

Anastomotic perfusion models were established using twelve rabbits distributed into two groups: group A (good perfusion, n = 6) and group B (poor perfusion, n = 6). Afterward, intraoperative detection of anastomotic perfusion was carried out using CLE, and quantitative analysis of blood cells was performed. Rabbits that satisfied the criteria underwent a second exploratory operation and specimens were stained by hematoxylin and eosin.

RESULTS

Enhanced with fluorescein sodium, capillaries were obviously highlighted in group A, while few capillaries were viewed in group B. Delayed development of fluorescence occurred in group B. The average flow of blood cells was 37.0 ± 5.93 per minute in group A and 6.33 ± 2.16 per minute in group B (p < 0.001). In addition, during the second exploratory surgery, rabbits with inadequate anastomotic perfusion exhibited more serious intestinal adhesion and ischemia. Anastomotic leakage and abdominal infection occurred in all rabbits in group B.

CONCLUSION

CLE can realize real-time imaging of the anastomotic microcirculation and is a feasible technique for performing intraoperative evaluation in different anastomotic perfusion situations. This animal experiment provides the groundwork for future in vivo research in humans.

Assessments of microvascular function in organ systems

Microvascular disease plays critical roles in the dysfunction of all organ systems, and there are many methods available to assess the microvasculature. These methods can either assess the target organ directly or assess an easily accessible organ such as the skin or retina so that inferences can be extrapolated to the other systems and/or related diseases. Despite the abundance of exploratory research on some of these modalities and their possible applications, there is a general lack of clinical use. This deficiency is likely due to two main reasons: the need for standardization of protocols to establish a role in clinical practice or the lack of therapies targeted toward microvascular dysfunction. Also, there remain some questions to be answered about the coronary microvasculature, as it is complex, heterogeneous, and difficult to visualize in vivo even with advanced imaging technology. This review will discuss novel approaches that are being used to assess microvasculature health in several key organ systems, and evaluate their clinical utility and scope for further development.

Effects of Fluid Therapy on Mesenteric Microcirculation Using New Probe-Based Confocal Laser Endomicroscopy (Cellvizio®) in a Porcine Model of Endotoxic Shock

BACKGROUND

Microcirculatory alterations have been observed at the early phase of sepsis, although macrocirculation seems preserved. The aim of this study was to analyze the effect of crystalloid fluid therapy on mesenteric microcirculation, assessed by using the confocal laser endomicroscope Cellvizio®, in an endotoxic porcine model.

METHODS

It is a prospective endotoxic shock (lipopolysaccharide infusion) experimental trial. Piglets were divided into 3 groups: 6 in the sham group (no LPS injection, no fluid), 9 in the control group (LPS infusion, no fluid), and 6 in the crystalloids group (LPS infusion and fluid resuscitation with crystalloids). Fluid resuscitation consisted in a fluid bolus of 20 mL/kg 0.9% saline over 30 min followed by a 10 mL/kg/h fluid rate over 4 h. Mesenteric microcirculation was assessed using a confocal laser endomicroscope (Cellvizio®). Blood flow within capillaries was visually assessed according to the point of care microcirculation (POEM) score.

RESULTS

At baseline, the 3 groups were similar regarding hemodynamic, biological, and microcirculatory parameters. At T360, the POEM score significantly decreased in the control and crystalloids groups, whereas it remained unchanged in the sham group (respectively, 1.62 ± 1.06, 1.2 ± 0.45, and 5.0 ± 0, p = 0.011). There was no significant difference in cardiac output at T360 between the sham and crystalloids groups (3.1 ± 0.8 vs. 2.3 ± 0.6, p = 0.132) or between the control and crystalloids groups (2.0 ± 0.6 vs. 2.3 ± 0.6, p = 0.90).

CONCLUSION

There was no significant improvement of microcirculatory alterations after crystalloids resuscitation despite improvement in macrocirculatory parameters in early experimental sepsis.

Feasibility and effectiveness of endoscopic irreversible electroporation for the upper gastrointestinal tract: an experimental animal study

Irreversible electroporation (IRE) is a local non-thermal ablative technique currently used to treat solid tumors. Here, we investigated the clinical potency and safety of IRE with an endoscope in the upper gastrointestinal tract. Pigs were electroporated with recently designed endoscopic IRE catheters in the esophagus, stomach, and duodenum. Two successive strategies were introduced to optimize the electrical energy for the digestive tract. First, each organ was electroporated and the energy upscaled to confirm the upper limit energy inducing improper tissue results, including bleeding and perforation. Excluding the unacceptable energy from the first step, consecutive electroporations were performed with stepwise reductions in energy to identify the energy that damaged each layer. Inceptive research into inappropriate electrical intensity contributed to extensive hemorrhage and bowel perforation for each tissue above a certain energy threshold. However, experiments performed below the precluded energy accompanying hematoxylin and eosin staining and terminal deoxynucleotidyl transferase dUTP nick-end labeling assays showed that damaged mucosal area and depth significantly decreased with decreased energy. Relevant histopathology showed infiltration of inflammatory cells with pyknotic nuclei at the electroporated lesion. This investigation demonstrated the possibility of endoscopic IRE in mucosal dysplasia or early malignant tumors of the hollow viscus.

A Novel Technique to Improve Anastomotic Perfusion Prior to Esophageal Surgery: Hybrid Ischemic Preconditioning of the Stomach. Preclinical Efficacy Proof in a Porcine Survival Model

Simple Summary

Esophagectomy has a high rate of anastomotic complications thought to be caused by poor perfusion of the gastric graft, which is used to restore the continuity of the gastrointestinal tract. Ischemic gastric preconditioning (IGP), performed by partially destroying preoperatively the gastric vessels either by means of interventional radiology or surgically, might improve the gastric conduit perfusion. Both approaches have downsides. The timing, extent and mechanism of IGP remain unclear. A novel hybrid IGP method combining the advantages of the endovascular and surgical approach was introduced in this study. IGP improves unequivocally the mucosal and serosal blood-flow at the gastric conduit fundus by triggering new vessels formation. The proposed timing and extent of IGP were efficacious and might be easily applied to humans. This novel minimally invasive IGP technique might reduce the anastomotic leak rate of patients undergoing esophagectomy, thus improving their overall oncological outcome.

Abstract

Esophagectomy often presents anastomotic leaks (AL), due to tenuous perfusion of gastric conduit fundus (GCF). Hybrid (endovascular/surgical) ischemic gastric preconditioning (IGP), might improve GCF perfusion. Sixteen pigs undergoing IGP were randomized: (1) Max-IGP (n = 6): embolization of left gastric artery (LGA), right gastric artery (RGA), left gastroepiploic artery (LGEA), and laparoscopic division (LapD) of short gastric arteries (SGA); (2) Min-IGP (n = 5): LGA-embolization, SGA-LapD; (3) Sham (n = 5): angiography, laparoscopy. At day 21 gastric tubulation occurred and GCF perfusion was assessed as: (A) Serosal-tissue-oxygenation (StO₂) by hyperspectral-imaging; (B) Serosal time-to-peak (TTP) by fluorescence-imaging; (C) Mucosal functional-capillary-density-area (FCD-A) index by confocal-laser-endomicroscopy. Local capillary lactates (LCL) were sampled. Neovascularization was assessed (histology/immunohistochemistry). Sham presented lower StO₂ and FCD-A index (41 ± 10.6%; 0.03 ± 0.03 respectively) than min-IGP (66.2 ± 10.2%, p-value = 0.004; 0.22 ± 0.02, p-value < 0.0001 respectively) and max-IGP (63.8 ± 9.4%, p-value = 0.006; 0.2 ± 0.02, p-value < 0.0001 respectively). Sham had higher LCL (9.6 ± 4.8 mL/mol) than min-IGP (4 ± 3.1, p-value = 0.04) and max-IGP (3.4 ± 1.5, p-value = 0.02). For StO₂, FCD-A, LCL, max- and min-IGP did not differ. Sham had higher TTP (24.4 ± 4.9 s) than max-IGP (10 ± 1.5 s, p-value = 0.0008) and min-IGP (14 ± 1.7 s, non-significant). Max- and min-IGP did not differ. Neovascularization was confirmed in both IGP groups. Hybrid IGP improves GCF perfusion, potentially reducing post-esophagectomy AL.

Shedding light on fibered confocal fluorescence microscopy: Applications in biomedical imaging and therapies

Discoveries of major importance in life sciences and preclinical research are linked to the invention of microscopes that enable imaging of cells and their microstructures. Imaging technologies involving in vivo procedures using fluorescent dyes that permit labelling of cells have been developed over the last two decades. Fibered confocal fluorescence microscopy (FCFM) is an imaging technology equipped with fiber-optic probes to deliver light to organs and tissues of live animals. This enables not only in vivo detection of fluorescent signals and visualization of cells, but also the study of dynamic processes, such cell proliferation, apoptosis and angiogenesis, under physiological and pathological conditions. This will allow the diagnosis of diseased organs and tissues and the evaluation of the efficacy of new therapies in animal models of human diseases. The aim of this report is to shed light on FCFM and its potential medical applications and discusses some factors that compromise the reliability and reproducibility of monitoring biological processes by FCFM. This report also highlights the issues concerning animal experimentation and welfare, and the contributions of FCFM to the 3Rs principals, replacement, reduction and refinement.

Imbalanced mucosal microcirculation in the remission stage of ulcerative colitis using probe-based confocal laser endomicroscopy

Background

Microcirculatory disturbance is an important factor in the pathogenesis of Inflammatory Bowel Disease (IBD) but there have been few studies in this field. Confocal Laser Endomicroscopy (CLE) has been used over the last 10 years and has made it possible to explore the changes in microcirculation of the colonic mucosa.

Methods

We retrospectively selected patients who underwent probe-based Confocal Laser Endomicroscopy (pCLE) between 2014 and 2016. There were 7 patients with ulcerative colitis (UC) in clinical remission and 7 healthy subjects included in this study; all the UC patients’ medical data were reviewed. For each patient, three segments of the colon were examined using pCLE including the ascending, transverse/descending and sigmoid colon. In each segment, the representative pCLE images of the three sites were selected for analysis. Four indicators, including Mean Vessel Diameter (MVD), Diameter Standard Deviation (DSD), Functional Capillary Density-long (FCDL) and Functional Capillary Density-area (FCDA), were measured with a specially designed detection software algorithm. The four indicators were compared between UC patients and healthy subjects. According to the different blood flow patterns, three types of distribution were established: the Around (A), Cobweb (C) and Deficiency (D) type. The relationships between the recurrence and blood flow patterns of UC patients were analyzed.

Results

MVD, DSD, FCDL and FCDA were 10.62 ± 0.56 μm, 2.23 ± 0.26, 0.030 ± 0.019 μm and 0.289 ± 0.030 for the healthy subjects and 11.06 ± 1.10 μm, 2.68 ± 0.29, 0.026 ± 0.005 μm and 0.272 ± 0.034 for the UC patients, respectively. Compared with healthy subjects, DSD was significantly increased and FCDA was significantly decreased (P < 0.01 for both). There was no difference in MVD and FCDL between UC patients and healthy subjects. The type A and type C blood flows were observed in healthy subjects (66.67 and 33.33%, respectively) while type C appears more in UC patients (71.3%) and type D blood flow could only be found in UC patients (14.29%) P < 0.01. UC patients who showed Type D blood flow had a shorter recurrence interval.

Conclusions

Some local mucosal capillary density in UC patients was decreased, particularly in the inflammation-affected segment. The three mucosal blood flow patterns can be used as an indicator of mucosal healing.

Feasibility of real-time intestinal bloodstream evaluation using probe-based confocal laser endomicroscopy in a porcine intestinal ischemia model

BACKGROUND

Intestinal ischemia can lead to fatal complications if left unrecognized during surgery. The current techniques of intraoperative microvascular assessment remain subjective. Probe-based confocal laser endomicroscopy (pCLE) has the potential to objectively evaluate microvascular blood flow in real-time setting. The present study evaluated the technical feasibility of real-time intestinal bloodstream evaluation using pCLE in a porcine intestinal ischemia model.

METHODS

Seven pigs were used. The intestinal ischemia model was prepared by sequentially dividing the mesenteric blood vessels. The intestinal bloodstream was evaluated on its serosal surface using pCLE (Cellvizio 488 probe, Ultra Mini O) at every 1-cm segment from a vessel-preservation border (i.e., the cut end of the vessel). Images of the blood vessels and flow of red blood cells (RBCs) in each visualized vessel were semi-qualitatively assessed using a 3-scale scoring system. In addition, 25 surgeons blindly assessed the 10 movies recorded at 0, 1, 2, 3, and 5 cm from a vessel-preservation border using a 4-scale scoring system to confirm the consistency of the evaluation of the pCLE system.

RESULTS

Images of the blood vessels were successfully obtained from the cut end of the vessel to the segment 4 cm away. Good unidirectional flow of RBCs was observed from the cut end to the 2-cm segment, whereas the flow became bidirectional between 2 and 3 cm segments. Beyond 4 cm, no flow images were obtained. The specimen obtained from the segment beyond 4 cm showed remarkable mucosal color change, which was confirmed as a necrotic change histologically. The evaluations from the cut end of the vessel to the segment 1 cm away by surgeons were excellent or good and it was almost consistent.

CONCLUSIONS

Real-time bloodstream evaluation using pCLE is feasible and potentially effective for predicting intestinal ischemia during surgery.

Capillary Flow Rates in the Duodenum of Pediatric Ulcerative Colitis Patients Are Increased and Unrelated to Inflammation

BACKGROUND AND AIM

Inflammatory bowel diseases (IBD), including Crohn disease (CD) and ulcerative colitis (UC), are chronic pediatric disorders. Changes in vasculature are described in IBD, but these could be secondary to inflammation and the role in pathogenesis is poorly understood. Assessing circulatory changes in typically unaffected sites in IBD (eg, duodenum), when inflammation is absent, can identify vascular changes associated with pathogenesis. The aim of the study is to measure capillary flow rates in duodenal mucosa using probe-based confocal laser endomicroscopy (pCLE) during endoscopy in children with IBD.

METHODS

Images of villi with visible blood vessels obtained using pCLE were captured as video sequences. Capillary flow rate (mm/s) was calculated by dividing the distance travelled by blood cells by the duration of the sequence. Flow rates were correlated with various clinical parameters.

RESULTS

Forty-five patients (22 non-IBD, 14 CD, 9 UC) were included in the study. Duodenal capillary flow rates were significantly higher in UC patients (0.75 ± 0.07 mm/s) as compared to non-IBD (0.57 ± 0.03) and CD (0.65 ± 0.04). There was no correlation between serum hemoglobin and albumin, disease activity indices, serum inflammatory markers, and capillary flow rates in patients.

CONCLUSIONS

This pilot study shows, for the first time, increased capillary blood flow in the duodenum of UC patients that was unrelated to inflammatory markers or disease activity. Thus, early vascular changes can be assessed using pCLE during endoscopy.

Development of an advanced diagnostic concept for intestinal inflammation: molecular visualisation of nitric oxide in macrophages by functional poly(lactic-co-glycolic acid) microspheres

We here describe a new approach to visualise nitric oxide (NO) in living macrophages by fluorescent NO-sensitive microspheres based on poly(lactic-co-glycolic acid) (PLGA). PLGA microspheres loaded with NO550 dye were prepared through a modified solvent-evaporation method. Microparticles were characterized by a mean hydrodynamic diameter of 3000 nm, zeta potential of -26.000 ± 0.351 mV and a PDI of 0.828 ± 0.298. Under abiotic conditions, NO release was triggered through UV radiation (254 nm) of 10 mM sodium nitroprusside dehydrate (SNP). After incubation, AZO550 microspheres exhibited an about 8-fold increased emission at 550 nm compared to NO550 particles. For biotic NO release, RAW 264.7 murine macrophages were activated with lipopolysaccharide (LPS) of Salmonella typhimurium. After treatment with NO550 microparticles, only activated cells caused a green particle fluorescence and could be detected by laser scanning microscopy. NO release was confirmed indirectly with Griess reaction. Our functional NO550 particles enable a simple and early evaluation of inflammatory and immunological processes. Furthermore, our results on particle-based NO sensing and previous studies in targeting intestinal inflammation via (PLGA)-based microspheres demonstrate that an advanced concept for visualizing intestinal inflammation is tangible.

Early traditional Chinese medicine bundle therapy for the prevention of sepsis acute gastrointestinal injury in elderly patients with severe sepsis

This study aimed to study the effect of early traditional Chinese medicine bundle therapy on the prevention of sepsis-associated acute gastrointestinal injury (AGI). This was a multicenter, prospective, observational, non-randomized cohort study of 296 consecutive patients with severe sepsis during 2013/3 and 2014/11; 150 patients received standard treatments (controls) and 146 received traditional Chinese medicine bundle therapy (intervention group) (herbal decoction gavage based on syndrome differentiation, Chinese acupuncture, application of mirabilite, and defecation mixture). D-lactic acid, diamine oxidase, endotoxin, gastrin, motilin, and intra-abdominal pressure were measured. AGI was categorized into four levels. Compared with controls, D-lactic acid, diamine oxidase, endotoxin, gastrin, and intra-abdominal pressure in the intervention group were decreased, and motilin was increased on day 7. AGI incidence in the intervention group was lower than in controls. GIF scores of the intervention AGI II and III groups were lower than in controls. The APACHE II scores of the intervention AGI II, III, and IV groups were lower than in controls. Compared with controls, mechanical ventilation time and ICU stay in the intervention group were shorter, and 28-day overall and AGI-attributed mortality were lower. For elderly patients with severe sepsis, early traditional Chinese medicine bundle therapy could decrease AGI incidence and improve prognosis.

Functional testing in the diagnosis of chronic mesenteric ischemia

Chronic mesenteric ischemia (CMI) results from insufficient oxygen delivery or utilization to meet metabolic demand. Two main mechanisms may lead to mesenteric ischemia: occlusion in the arteries or veins of the gastrointestinal tract, or reduced blood flow from shock states or increased intra-abdominal pressure, so-called non-occlusive mesenteric ischemia. Severe stenoses in the three main mesenteric vessels as demonstrated with CT-angiography or MR-angiography are sufficient to proof mesenteric ischemia, for example in patients who present with weight loss, postprandial pain and diarrhea. Still in many clinical situations mesenteric ischemia is only one of many possible explanations. Especially in patients with a single vessel stenosis in the celiac artery or superior mesenteric artery with postprandial pain, mesenteric ischemia remains a diagnosis of probability or assumption without functional proof of actual ischemia. This review is aimed to provide an overview of all past, present and future ways to functionally proof CMI.

Role of hypoxia-inducible factor-1α in pathogenesis and disease evaluation of ulcerative colitis

The main aim of the present study was to measure hypoxia-inducible factor-1α (HIF-1α) in serum and colonic mucosa of ulcerative colitis (UC) patients and to analyze its role in the pathogenesis, disease activity and severity of UC. A total of 47 UC patients and 13 UC in remission patients were recruited for the present study. Ten healthy subjects were also included to serve as controls. HIF-1α in the serum was measured using ELISA. The citrate-microwave-SP immunohistochemical method was used to measure the expression of HIF-1α in colonic mucosa. The results showed that, HIF-1α in serum was notably higher in UC patients (73.21±28.65) than UC in remission patients (44.54±14.75) and controls (42.83±15.49). The difference between UC patients and UC in remission patients was significant (P<0.05). A correlation analysis revealed that, the HIF-1α level in serum was positively associated with disease activity, disease severity and endoscopic grade. The expression of HIF-1α in colonic mucosa of UC patients was (58.05±13.83) higher than that in UC in remission patients (3.00±2.72) and controls (3.04±2.69) and this difference was statistically significant (P<0.05). A positive correlation was identified between the expression of HIF-1α in colonic mucosa and the disease activity, severity and endoscopic grade. Thus, the present findings indicated that, HIF-1α is likely to play an important role in the pathogenesis of UC and may serve as a biomarker to evaluate disease activity and severity in UC patients.

Human colorectal mucosal microbiota correlates with its host niche physiology revealed by endomicroscopy

The human gut microbiota plays a pivotal role in the maintenance of health, but how the microbiota interacts with the host at the colorectal mucosa is poorly understood. We proposed that confocal laser endomicroscopy (CLE) might help to untangle this relationship by providing in vivo physiological information of the mucosa. We used CLE to evaluate the in vivo physiology of human colorectal mucosa, and the mucosal microbiota was quantified using 16 s rDNA pyrosequencing. The human mucosal microbiota agglomerated to three major clusters dominated by Prevotella, Bacteroides and Lactococcus. The mucosal microbiota clusters did not significantly correlate with the disease status or biopsy sites but closely correlated with the mucosal niche physiology, which was non-invasively revealed by CLE. Inflammation tilted two subnetworks within the mucosal microbiota. Infiltration of inflammatory cells significantly correlated with multiple components in the predicted metagenome, such as the VirD2 component of the type IV secretory pathway. Our data suggest that a close correlation exists between the mucosal microbiota and the colorectal mucosal physiology, and CLE is a clinically available tool that can be used to facilitate the study of the in vivo correlation between colorectal mucosal physiology and the mucosal microbiota.

Probe-based confocal laser endomicroscopy and fluorescence-based enhanced reality for real-time assessment of intestinal microcirculation in a porcine model of sigmoid ischemia

BACKGROUND AND AIM

Surgeons currently rely on visual clues to estimate the presence of sufficient vascularity for safe anastomosis. We aimed to assess the accuracy of endoluminal confocal laser endomicroscopy (CLE) and laparoscopic fluorescence-based enhanced reality (FLER), using near-infrared imaging and fluorescence from injected Indocyanine Green, to identify the transition from ischemic to vascular areas in a porcine model of mesenteric ischemia.

METHODS

Six pigs underwent 1-h sigmoid segmental ischemia. The ischemic area was evaluated by clinical assessment and FLER to determine presumed viable margins. For each sigmoid colon, 5 regions of interest (ROIs) were identified: ischemic (ROI 1), presumed viable margins ROI 2a (distal) and 2b (proximal), and vascular areas 3a (distal) and 3b (proximal). After injection of fluorescein, CLE scanning of the mucosa from the ischemic area toward viable margins was performed. Capillary blood samples were obtained by puncturing the serosa at the ROIs, and capillary lactates were measured with the EDGE(®) analyzer.

RESULTS

Capillary lactates were significantly higher at ROI 1 (4.91 mmol/L) when compared to resection margins (2.8 mmol/L; mean difference: 2.11; p < 0.05) identified by FLER. There was no significant difference in lactates between ROI1 and resection margins identified by clinical evaluation. In 50 % of cases, ROI 2aCLINIC-2bCLINIC were considered to match (<1 cm distance) with ROI 2aFLER-2bFLER. Confocal analysis revealed specific clues to identify the transition from ischemic to viable areas corresponding to those assessed by FLER in 11/12 cases versus 7/12 for those identified by clinical evaluation.

CONCLUSIONS

In this experimental model, FLER and CLE were more accurate than clinical evaluation to delineate bowel vascularization.