van Gooitzen Dam

Bone marrow-derived myofibroblasts contribute functionally to scar formation after myocardial infarction.

Myofibroblasts play a major role in scar formation during wound healing after myocardial infarction (MI). Their origin has been thought to be interstitial cardiac fibroblasts. However, the bone marrow (BM) can be a source of myofibroblasts in a number of organs after injury. We have studied the temporal, quantitative and functional role of BM‐derived (BMD) myofibroblasts in myocardial scar formation. MI was induced by permanent coronary artery ligation in mice reconstituted with EGFP or pro‐Col1A2 transgenic BM. In the latter, luciferase and β‐galactosidase transgene expression mirrors that of the endogenous pro‐collagen 1A2 gene, which allows for functional assessment of the recruited cells. After MI, α‐SMA‐positive myofibroblasts and collagen I gradually increased in the infarct area until day 14 and remained constant afterwards. Numerous EGFP‐positive BMD cells were present during the first week post‐MI, and gradually decreased afterwards until day 28. Peak numbers of BMD myofibroblasts, co‐expressing EGFP and α‐SMA, were found on day 7 post‐MI. An average of 21% of the BMD cells in the infarct area were myofibroblasts. These cells constituted up to 24% of all myofibroblasts present. By in vivo IVIS® imaging, BMD myofibroblasts were found to be active for collagen I production and their presence was confined to the infarct area. These results show that BMD myofibroblasts participate actively in scar formation after MI. Copyright

Sentinel node mapping with indocyanine green (ICG) and infrared ray detection in early gastric cancer: An accurate method that enables a limited lymphadenectomy

AIM This study compares lymphatic mapping in early gastric cancer with ICG and infrared ray electronic endoscopy (IREE) to ICG alone. It examines the optimal method for intra-operative detection of metastases and shows long term follow up results. METHODS 212 patients underwent the SN procedure with IREE and peritumoural ICG injection. Evaluated parameters were detection of sentinel nodes with IREE versus ICG alone, intra-operative detection rate of lymph node (LN) metastasis with node picking versus lymphatic basin dissection (LBD) and lymphatic drainage patterns. RESULTS 34 patients had LN metastases. The SN identification rate and sensitivity for IREE versus ICG alone were 99.5 versus 85.8% and 97.0 versus 48.4% respectively. Intra-operative accuracy for detecting LN metastasis was 50% with node picking versus 92.3% with LBD. LN metastases were always in the SN basin. Lymphatic invasion and T-stage were risk factors for nodal metastases. Two patients showed recurrent disease. Both had a tumour with signet cell differentiation. One patient had a T3 tumour, the other patient had a tumour with a diameter of 85 mm. CONCLUSION The SN procedure with IREE can detect the SN and is better than ICG alone. LBD of the SN basin is required for accurate intra-operative diagnosis of metastases. LBD dissection based on IREE is a safe method of nodal dissection in patients with T1 or limited T2 tumours.

Advanced carotid plaque imaging.

Treatment of carotid artery stenosis by endarterectomy or stenting can significantly reduce stroke risk. In clinical practice, indication for surgery or stenting is primarily based on the degree of stenosis, but there is growing awareness that pathophysiological features within a vulnerable plaque play a key role in predicting stroke risk. Important molecular processes associated with plaque vulnerability are inflammation, lipid accumulation, proteolysis, apoptosis, angiogenesis and thrombosis. The rapidly emerging field of molecular and functional imaging strategies allows identification of pathophysiological processes in carotid artery stenosis. We aimed to review the literature regarding the current most promising advanced imaging techniques in carotid artery disease. Various advanced imaging methods are available, such as high-resolution magnetic resonance imaging (HR-MRI), single photon emission computed tomography (SPECT), positron emission tomography (PET) and near-infrared fluorescence (NIRF). Radionuclide and fluorescent tracers that identify inflammation, apoptosis and proteolysis, such as FDG, MMP probes and Annexin A5, are promising. A combination of activity of molecular processes and detailed anatomic information can be obtained, providing a powerful tool in the identification of the vulnerable plaque. With these developments, we are entering a new era of imaging techniques in the selection of patients for carotid surgery.

Optical innovations in surgery.

In the past decade, there has been a major drive towards clinical translation of optical and, in particular, fluorescence imaging in surgery. In surgical oncology, radical surgery is characterized by the absence of positive resection margins, a critical factor in improving prognosis. Fluorescence imaging provides the surgeon with reliable and real‐time intraoperative feedback to identify surgical targets, including positive tumour margins. It also may enable decisions on the possibility of intraoperative adjuvant treatment, such as brachytherapy, chemotherapy or emerging targeted photodynamic therapy (photoimmunotherapy).

Intraoperative assessment of microperfusion with visible light spectroscopy for prediction of anastomotic leakage in colorectal anastomoses

Purpose  Anastomotic leakage is associated with increased morbidity and mortality. However, there is no accurate tool to predict its occurrence. We evaluated the predictive value of visible light spectroscopy (VLS), a novel method to measure tissue oxygenation [saturated O2 (StO2)], for anastomotic leakage of the colon and the rectum.

Real-time near infrared fluorescence (NIRF) intra-operative imaging in ovarian cancer using an αvβ3-integrin targeted agent

BACKGROUND In ovarian cancer, optimal cytoreductive surgery is of the utmost importance for long-term survival. The ability to visualize minuscule tumor deposits is important to ensure complete resection of the tumor. The purpose of our study was to estimate the in vivo sensitivity, specificity and diagnostic accuracy of an intra-operative fluorescence imaging system combined with an α(v)β(3)-integrin targeted near-infrared fluorescent probe. METHOD Tumor bearing mice were injected intravenously with a fluorescent probe targeting α(v)β(3) integrins. Fluorescent spots and non-fluorescent tissue were identified and resected. Standard histopathology and fluorescence microscopy were used as gold-standard for tumor detection. RESULTS Fifty-eight samples excised with support of intra-operative image-guided surgery were analyzed. The mean target to background ratio was 2.2 (SD 0.5). The calculated sensitivity of the imaging system was 95%, and the specificity was 88% with a diagnostic accuracy of 96.5%. CONCLUSION Near-infrared image-guided surgery in this model has a high diagnostic accuracy and a fair target to background ratio that supports the development towards clinical translation of α(v)β(3)-integrin targeted imaging.

Safety Measures During Cholecystectomy: Results of a Nationwide Survey

BackgroundThis study aimed to identify safety measures practiced by Dutch surgeons during laparoscopic cholecystectomy.MethodAn electronic questionnaire was sent to all members of the Dutch Society of Surgery with a registered e-mail address.ResultsThe response rate was 40.4% and 453 responses were analyzed. The distribution of the respondents with regard to type of hospital was similar to that in the general population of Dutch surgeons. The critical view of safety (CVS) technique is used by 97.6% of the surgeons. It is documented by 92.6%, mostly in the operation report (80.0%), but often augmented by photography (42.7%) or video (30.2%). If the CVS is not obtained, 50.9% of surgeons convert to the open approach, 39.1% continue laparoscopically, and 10.0% perform additional imaging studies. Of Dutch surgeons, 53.2% never perform intraoperative cholangiography (IOC), 41.3% perform it incidentally, and only 2.6% perform it routinely. A total of 105 bile duct injuries (BDIs) were reported in 14,387 cholecystectomies (0.73%). The self-reported major BDI rate (involving the common bile duct) was 0.13%, but these figures need to be confirmed in other studies.ConclusionThe CVS approach in laparoscopic cholecystectomy is embraced by virtually all Dutch surgeons. The course of action when CVS is not obtained varies. IOC seems to be an endangered skill as over half the Dutch surgeons never perform it and the rest perform it only incidentally.

Intraoperative Assessment of Microperfusion with Visible Light Spectroscopy in Esophageal and Colorectal Anastomoses

Background: We evaluated the technical feasibility and stability of measurements using visible light spectroscopy to measure microvascular oxygen saturation (StO2) in gastrointestinal anastomoses. Methods: In consecutive esophageal (n = 14) or colorectal (n = 30) resections, during which an uncomplicated anastomosis was performed, measurements of serosal StO2 were performed during the procedure. Results: In esophageal resections, median (± standard error) StO2 was stable before and after anastomosis in the proximal esophagus (before: 66.0 ± 4.6, after: 68.3 ± 6.0%) and the gastric conduit (before: 70.6 ± 8.6, after: 69.8 ± 8.0%). Mean colorectal StO2 before and after anastomosis increased in the proximal part (71.3 ± 8.4 to 76.6 ± 8.2%; p < 0.005). Mean StO2 in the distal part remained stable (72.4 ± 6.6 to 74.8 ± 6.7%). Conclusions: Visible light spectroscopy is a feasible and fast method for intraoperative assessment of microperfusion of the serosa in esophageal and colorectal anastomosis. Future clinical studies will define its role in the prediction of anastomotic leakage.

A validated web-based nomogram for predicting positive surgical margins following breast-conserving surgery as a preoperative tool for clinical decision-making

BACKGROUND Breast-conserving therapy, consisting of lumpectomy and adjuvant radiotherapy, is considered standard treatment for early-stage breast cancer. One of the most important risk factors of local recurrence is the presence of positive surgical margins following lumpectomy. We aimed to develop and validate a predictive model (nomogram) to predict for positive margins following the first attempt at lumpectomy as a preoperative tool for clinical decision-making. METHODS Patients with clinical T1-2N0-1Mx-0 histology-proven invasive breast carcinoma who underwent BCT throughout the North-East region of The Netherlands between June 2008 and July 2009 were selected from the Netherlands Cancer Registry (n = 1185). Results from multivariate logistic regression analyses served as the basis for development of the nomogram. Nomogram calibration and discrimination were assessed graphically and by calculation of a concordance index, respectively. Nomogram performance was validated on an external independent dataset (n = 331) from the University Medical Center Groningen. RESULTS The final multivariate regression model included clinical, radiological, and pathological variables. Concordance indices were calculated of 0.70 (95% CI: 0.66-0.74) and 0.69 (95% CI: 0.63-0.76) for the modeling and the validation group, respectively. Calibration of the model was considered adequate in both groups. A nomogram was developed as a graphical representation of the model. Moreover, a web-based application (http://www.breastconservation.com) was build to facilitate the use of our nomogram in a clinical setting. CONCLUSION We developed and validated a nomogram that enables estimation of the preoperative risk of positive margins in breast-conserving surgery. Our nomogram provides a valuable tool for identifying high-risk patients who might benefit from preoperative MRI and/or oncoplastic surgery.

Expression of EpCAM is up-regulated during regeneration of renal epithelia†

The human epithelial cell adhesion molecule (hEpCAM) is involved in epithelial morphogenesis and repair of epithelial tissues. We hypothesized that changes in hEpCAM expression in vivo correlate with regeneration of renal epithelia after ischaemia/reperfusion injury (IRi). Unilateral IRi was performed on kidneys of hEpCAM transgenic mice. Changes in hEpCAM expression were investigated by quantitative RT‐PCR in renal cortex and medulla dissected by laser dissection microscopy and expression patterns of hEpCAM in regenerating kidneys were assessed by immunohistochemistry. The mechanism of hEpCAM promoter activation was investigated in vitro, by real‐time bioluminescent imaging in HK‐2 cells and in primary tubular epithelial cells (PTECs) subjected to hypoxia and reoxygenation. In vivo, the transcription of the human epcam gene significantly increased in the renal cortex during tubular re‐epithelialization (p < 0.01). Moreover, the number of tubuli that expressed hEpCAM protein more than doubled in the renal cortex during regeneration. De novo expression of hEpCAM was detected in the S1 segments of proximal tubuli. Under hypoxic conditions in vitro, activity of the hEpCAM promoter was up‐regulated two‐fold in the HK‐2 proximal epithelial cell line. Moreover, both in primary proximal epithelial cells and in HK‐2 cells, hEpCAM protein expression was increased after hypoxia and reoxygenation. The significant up‐regulation of hEpCAM during post‐ischaemic renal regeneration in vivo and during in vitro hypoxia indicates that hEpCAM expression is associated with renal regeneration. Copyright