Laparoscopic versus open adhesiolysis for adhesive small bowel obstruction (LASSO): an international, multicentre, randomised, open-label trial

BACKGROUND

Although laparoscopic adhesiolysis for adhesive small bowel obstruction is being done more frequently, it is not widely accepted due to the lack of supporting evidence of its superiority over an open approach and concerns regarding its benefits. We aimed to investigate whether laparoscopic adhesiolysis was a superior treatment for adhesive small bowel obstruction compared with an open approach in terms of length of postoperative hospital stay and morbidity.

METHODS

In this international, multicentre, parallel, open-label trial, we randomly assigned patients (1:1) aged 18-95 years who had adhesive small bowel obstruction that had not resolved with conservative management to have either open or laparoscopic adhesiolysis. The study was done in five academic university hospitals and three community (central) hospitals in two countries (Finland [n=3 academic university hospitals; n=3 community hospitals] and Italy [n=2 academic university hospitals]). We included only patients with high likelihood of a single adhesive band in the trial; additionally, patients who had an anaesthesiological contraindication, were pregnant, living in institutionalised care, or who had a hospital stay of more than 1 week before the surgical consultation were excluded from the trial. The randomisation sequence was generated using block randomisation, with randomly varied block sizes and stratified according to centre. The primary outcome was postoperative length of hospital stay assessed at time of discharge in the modified intention-to-treat population.

FINDINGS

Between July 18, 2013, and April 9, 2018, 566 patients were assessed for eligibility, of whom 104 patients were randomly assigned to the open surgery group (n=51) or to the laparoscopy group (n=53). Of these patients, 100 were included in the modified intention-to-treat analyses (49 in the open surgery group; 51 in the laparoscopy group). The postoperative length of hospital stay for open surgery group was on average 1·3 days longer than that in the laparoscopy group (geometric mean 5·5 days [range 2-19] vs 4·2 days [range 1 -20]; ratio of geometric means 1·31 [95% CI 1·06-1·61]; p=0·013). 21 (43%) patients in the open surgery group and 16 (31%) patients in the laparoscopy group had postoperative complications (Clavien-Dindo any grade) within 30 days (odds ratio 0·61 [95% CI 0·27-1·38]; p=0·23). One patient died in each group within 30 days.

INTERPRETATION

Laparoscopic adhesiolysis provides quicker recovery in selected patients with adhesive small bowel obstruction than open adhesiolysis.

FUNDING

Vatsatautien Tutkimussäätiö Foundation, Mary and Georg Ehrnrooth's Foundation, Martti I Turunen Foundation, and governmental (Finland) competitive research funds (EVO/VTR/TYH).

Laparoscopic versus open adhesiolysis for small bowel obstruction - a multicenter, prospective, randomized, controlled trial

Background

Laparoscopic adhesiolysis is emerging as an alternative for open surgery in adhesive small bowel obstruction. Retrospective studies suggest that laparoscopic approach shortens hospital stay and reduces complications in these patients. However, no prospective, randomized, controlled trials comparing laparoscopy to open surgery have been published.

Methods/Design

This is a multicenter, prospective, open label, randomized, controlled trial comparing laparoscopic adhesiolysis to open surgery in patients with computed-tomography diagnosed adhesive small bowel obstruction that is not resolving with conservative management. The primary study endpoint is the length of postoperative hospital stay in days.

Sample size was estimated based on preliminary retrospective cohort, which suggested that 102 patients would provide 80% power to detect a difference of 2.5 days in the length of postoperative hospital stay with significance level of 0.05. Secondary endpoints include passage of stool, commencement of enteral nutrition, 30-day mortality, complications, postoperative pain, and the length of sick leave. Tertiary endpoints consist of the rate of ventral hernia and the recurrence of small bowel obstruction during long-term follow-up. Long-term follow-up by letter or telephone interview will take place at 1, 5, and 10 years.

Discussion

To the best of our knowledge, this trial is the first one aiming to provide level Ib evidence to assess the use of laparoscopy in the treatment of adhesive small bowel obstruction.

Trial registration

ClinicalTrials.gov identifier: NCT01867528. Date of registration May 26th 2013.

Preoperative assessment and treatment of appendiceal mucocele complicated by acute torsion: a case report

Background

Mucus-producing tumours of the appendix or mucoceles can, if left untreated, lead to dissemination of its contents into the peritoneal cavity causing substantial morbidity to the patient. Symptoms for complicated mucoceles can mimic those of acute appendicitis and the final diagnosis is most likely made intraoperatively. We here present a case that is, to our knowledge, one of only ten described in the literature and the first to characterize torsion of an appendiceal mucocele with abdominal magnetic resonance imaging.

Case presentation

The patient, a 34-year-old Caucasian female presented at the emergency department with acute abdominal pain in the right lower quadrant. Initial diagnostic work-up including ultrasonography and abdominal magnetic resonance imaging showed a large tubular mass at the base of the appendix with indirect signs of torsion. A laparoscopic appendectomy was performed the following day where the finding was confirmed. The patient went on to have an uneventful recovery and was discharged from the hospital on the first postoperative day.

Conclusions

Magnetic resonance imaging is a useful tool in identifying unknown lesions of the appendix and should be considered the primary imaging modality in especially younger patients requiring diagnostic imaging. In this case the preoperative imaging findings aided in choosing the correct timing and treatment option for the patient.

Vascular endothelial growth factor-B induces myocardium-specific angiogenesis and arteriogenesis via vascular endothelial growth factor receptor-1- and neuropilin receptor-1-dependent mechanisms

BACKGROUND

New revascularization therapies are urgently needed for patients with severe coronary heart disease who lack conventional treatment options.

METHODS AND RESULTS

We describe a new proangiogenic approach for these no-option patients using adenoviral (Ad) intramyocardial vascular endothelial growth factor (VEGF)-B186 gene transfer, which induces myocardium-specific angiogenesis and arteriogenesis in pigs and rabbits. After acute infarction, AdVEGF-B186 increased blood vessel area, perfusion, ejection fraction, and collateral artery formation and induced changes toward an ischemia-resistant myocardial phenotype. Soluble VEGF receptor-1 and soluble neuropilin receptor-1 reduced the effects of AdVEGF-B186, whereas neither soluble VEGF receptor-2 nor inhibition of nitric oxide production had this result. The effects of AdVEGF-B186 involved activation of neuropilin receptor-1, which is highly expressed in the myocardium, via recruitment of G-protein-alpha interacting protein, terminus C (GIPC) and upregulation of G-protein-alpha interacting protein. AdVEGF-B186 also induced an antiapoptotic gene expression profile in cardiomyocytes and had metabolic effects by inducing expression of fatty acid transport protein-4 and lipid and glycogen accumulation in the myocardium.

CONCLUSIONS

VEGF-B186 displayed strikingly distinct effects compared with other VEGFs. These effects may be mediated at least in part via a G-protein signaling pathway. Tissue-specificity, high efficiency in ischemic myocardium, and induction of arteriogenesis and antiapoptotic and metabolic effects make AdVEGF-B186 a promising candidate for the treatment of myocardial ischemia.

Reevaluation of the role of VEGF-B suggests a restricted role in the revascularization of the ischemic myocardium

OBJECTIVE

The endogenous role of the VEGF family member vascular endothelial growth factor-B (VEGF-B) in pathological angiogenesis remains unclear.

METHODS AND RESULTS

We studied the role of VEGF-B in various models of pathological angiogenesis using mice lacking VEGF-B (VEGF-B(-/-)) or overexpressing VEGF-B(167). After occlusion of the left coronary artery, VEGF-B deficiency impaired vessel growth in the ischemic myocardium whereas, in wild-type mice, VEGF-B(167) overexpression enhanced revascularization of the infarct and ischemic border zone. By contrast, VEGF-B deficiency did not affect vessel growth in the wounded skin, hypoxic lung, ischemic retina, or ischemic limb. Moreover, VEGF-B(167) overexpression failed to enhance vascular growth in the skin or ischemic limb.

CONCLUSIONS

VEGF-B appears to have a relatively restricted angiogenic activity in the ischemic heart. These insights might offer novel therapeutic opportunities.

The biology of vascular endothelial growth factors

The discovery of the vascular endothelial growth factor (VEGF) family members VEGF, VEGF-B, placental growth factor (PlGF), VEGF-C and VEGF-D and their receptors VEGFR-1, -2 and -3 has provided tools for studying the vascular system in development as well as in diseases ranging from ischemic heart disease to cancer. VEGF has been established as the prime angiogenic molecule during development, adult physiology and pathology. PlGF may primarily mediate arteriogenesis, the formation of collateral arteries from preexisting arterioles, with potential future therapeutic use in for example occlusive atherosclerotic disease. VEGF-C and VEGF-D are primarily lymphangiogenic factors, but they can also induce angiogenesis in some conditions. While many studies have addressed the role of angiogenesis and the blood vasculature in human physiology, the lymphatic vascular system has until recently attracted very little attention. In this review, we will discuss recent advances in angiogenesis research and provide an overview of the molecular players involved in lymphangiogenesis.

Vascular endothelial growth factor-C: a growth factor for lymphatic and blood vascular endothelial cells

The endothelial cells lining all vessels of the circulatory system have been recognized as key players in a variety of physiological and pathological settings. They act as regulators of vascular tone via the inducible nitric oxide system and in angiogenesis, the formation of blood vessels de novo. Aberrant regulation of endothelial cells contributes to tumor formation, atherosclerosis, and diseases such as psoriasis and rheumatoid arthritis. Among the most recently discovered growth factors for endothelial cells are newly isolated members of the platelet-derived growth factor/vascular endothelial growth factor (VEGF) family, VEGF-B, VEGF-C, and VEGF-D. VEGF-C is the ligand for the receptor tyrosine kinase VEGFR-3 (also known as Flt4), which is expressed predominantly in lymphatic endothelium of adult tissues, but a proteolytically processed form of VEGF-C can also activate VEGFR-2 of blood vessels. The lymphatic vessels have been known since the 17th century, but their specific roles in health and disease are still poorly understood. With the discovery of VEGF-C and its cognate receptor VEGFR-3, the regulation and functions of this important component of the circulatory system can be investigated.

Lymphangiogenic gene therapy with minimal blood vascular side effects

Recent work from many laboratories has demonstrated that the vascular endothelial growth factor-C/VEGF-D/VEGFR-3 signaling pathway is crucial for lymphangiogenesis, and that mutations of the Vegfr3 gene are associated with hereditary lymphedema. Furthermore, VEGF-C gene transfer to the skin of mice with lymphedema induced a regeneration of the cutaneous lymphatic vessel network. However, as is the case with VEGF, high levels of VEGF-C cause blood vessel growth and leakiness, resulting in tissue edema. To avoid these blood vascular side effects of VEGF-C, we constructed a viral vector for a VEGFR-3-specific mutant form of VEGF-C (VEGF-C156S) for lymphedema gene therapy. We demonstrate that VEGF-C156S potently induces lymphangiogenesis in transgenic mouse embryos, and when applied via viral gene transfer, in normal and lymphedema mice. Importantly, adenoviral VEGF-C156S lacked the blood vascular side effects of VEGF and VEGF-C adenoviruses. In particular, in the lymphedema mice functional cutaneous lymphatic vessels of normal caliber and morphology were detected after long-term expression of VEGF-C156S via an adeno associated virus. These results have important implications for the development of gene therapy for human lymphedema.

Adenoviral VEGF-C overexpression induces blood vessel enlargement, tortuosity, and leakiness but no sprouting angiogenesis in the skin or mucous membranes

Vascular endothelial growth factors (VEGFs) and their receptors (VEGFRs) are important regulators of blood and lymphatic vessel growth and vascular permeability. The VEGF-C/VEGFR-3 signaling pathway is crucial for lymphangiogenesis, and heterozygous inactivating missense mutations of the VEGFR-3 gene are associated with hereditary lymphedema. However, VEGF-C can have potent effects on blood vessels because its receptor VEGFR-3 is expressed in certain blood vessels and because the fully processed form of VEGF-C also binds to the VEGFR-2 of blood vessels. To characterize the in vivo effects of VEGF-C on blood and lymphatic vessels, we have overexpressed VEGF-C via adenovirus- and adeno-associated virus-mediated transfection in the skin and respiratory tract of athymic nude mice. This resulted in dose-dependent enlargement and tortuosity of veins, which, along with the collecting lymphatic vessels were found to express VEGFR-2. Expression of angiopoietin 1 blocked the increased leakiness of the blood vessels induced by VEGF-C whereas vessel enlargement and lymphangiogenesis were not affected. However, angiogenic sprouting of new blood vessels was not observed in response to AdVEGF-C or AAV-VEGF-C. These results show that virally produced VEGF-C induces blood vessel changes, including vascular leak, but its angiogenic potency is much reduced compared with VEGF in normal skin.

Expression of vascular endothelial growth factor receptor 3 in blood and lymphatic vessels of lung adenocarcinoma

Vascular endothelial growth factor receptor 3 (VEGFR-3) has been proposed as a marker for lymphatic endothelial cells. This study investigated the expression of VEGFR-3 in the tumour vessels of lung adenocarcinoma and evaluated whether VEGFR-3 staining was useful for identifying lymphatic vessels within the tumour stroma. It also explored whether active growth of lymphatic vessels occurred in lung adenocarcinoma. Formalin-fixed, paraffin-embedded specimens obtained from 60 cases of lung adenocarcinoma, including five cases of pure bronchiolo-alveolar carcinoma (BAC) without stromal, vascular, and pleural invasion, were examined. No VEGFR-3-positive vessels were observed in pure BAC, but varying numbers of VEGFR-3-positive vessels were found in 39 of 55 (70.9%) invasive adenocarcinomas. A comparison of serial sections stained for VEGFR-3, CD31, and laminin-1 showed that most of the VEGFR-3-positive vessels appeared to be blood vessels (CD31-positive, laminin-1-positive), but some had the characteristics of lymphatic vessels (variable staining for CD31, little or no staining for laminin-1). VEGFR-3 staining highlighted lymphatic invasion by cancer cells; this invasion could not be detected by CD31 or haematoxylin and eosin (H&E) staining. Active growth of lymphatic vessels (as indicated by nuclear Ki-67 labelling of the endothelium) was observed in five tumours, four of which showed a high level of lymphatic invasion by cancer cells. It was concluded that VEGFR-3 immunostaining did not discriminate clearly between vascular and lymphatic endothelial cells, since expression of VEGFR-3 can be up-regulated in tumour blood vessels. However, VEGFR-3 staining combined with laminin-1 and CD31 staining would be useful for identifying lymphatic vessels and their invasion by tumour cells in a more objective way. Finally, proliferation of lymphatic endothelial cells may occur in association with lymphatic invasion by cancer cells.

Adenoviral expression of vascular endothelial growth factor-C induces lymphangiogenesis in the skin

The growth of blood and lymphatic vasculature is mediated in part by secreted polypeptides of the vascular endothelial growth factor (VEGF) family. The prototype VEGF binds VEGF receptor (VEGFR)-1 and VEGFR-2 and is angiogenic, whereas VEGF-C, which binds to VEGFR-2 and VEGFR-3, is either angiogenic or lymphangiogenic in different assays. We used an adenoviral gene transfer approach to compare the effects of these growth factors in adult mice. Recombinant adenoviruses encoding human VEGF-C or VEGF were injected subcutaneously into C57Bl6 mice or into the ears of nude mice. Immunohistochemical analysis showed that VEGF-C upregulated VEGFR-2 and VEGFR-3 expression and VEGF upregulated VEGFR-2 expression at 4 days after injection. After 2 weeks, histochemical and immunohistochemical analysis, including staining for the lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1), the vascular endothelial marker platelet-endothelial cell adhesion molecule-1 (PECAM-1), and the proliferating cell nuclear antigen (PCNA) revealed that VEGF-C induced mainly lymphangiogenesis in contrast to VEGF, which induced only angiogenesis. These results have significant implications in the planning of gene therapy using these growth factors.

Intravascular adenovirus-mediated VEGF-C gene transfer reduces neointima formation in balloon-denuded rabbit aorta

BACKGROUND

Gene transfer to the vessel wall may provide new possibilities for the treatment of vascular disorders, such as postangioplasty restenosis. In this study, we analyzed the effects of adenovirus-mediated vascular endothelial growth factor (VEGF)-C gene transfer on neointima formation after endothelial denudation in rabbits. For comparison, a second group was treated with VEGF-A adenovirus and a third group with lacZ adenovirus. Clinical-grade adenoviruses were used for the study.

METHODS AND RESULTS

Aortas of cholesterol-fed New Zealand White rabbits were balloon-denuded, and gene transfer was performed 3 days later. Animals were euthanized 2 and 4 weeks after the gene transfer, and intima/media ratio (I/M), histology, and cell proliferation were analyzed. Two weeks after the gene transfer, I/M in the lacZ-transfected control group was 0. 57+/-0.04. VEGF-C gene transfer reduced I/M to 0.38+/-0.02 (P:<0.05 versus lacZ group). I/M in VEGF-A-treated animals was 0.49+/-0.17 (P:=NS). The tendency that both VEGF groups had smaller I/M persisted at the 4-week time point, when the lacZ group had an I/M of 0.73+/-0.16, the VEGF-C group 0.44+/-0.14, and the VEGF-A group 0. 63+/-0.21 (P:=NS). Expression of VEGF receptors 1, 2, and 3 was detected in the vessel wall by immunocytochemistry and in situ hybridization. As an additional control, the effect of adenovirus on cell proliferation was analyzed by performing gene transfer to intact aorta without endothelial denudation. No differences were seen in smooth muscle cell proliferation or I/M between lacZ adenovirus and 0.9% saline-treated animals.

CONCLUSIONS

Adenovirus-mediated VEGF-C gene transfer may be useful for the treatment of postangioplasty restenosis and vessel wall thickening after vascular manipulations.

Vascular endothelial growth factors VEGF-B and VEGF-C are expressed in human tumors

The growth of solid tumors is dependent on angiogenesis, the formation of new blood vessels. Vascular endothelial growth factor (VEGF) is a secreted endothelial-cell-specific mitogen. We have recently characterized two novel endothelial growth factors with structural homology to VEGF and named them VEGF-B and VEGF-C. To further define the roles of VEGF-B and VEGF-C, we have studied their expression in a variety of human tumors, both malignant and benign. VEGF-B mRNA was detected in most of the tumor samples studied, and the mRNA and the protein product were localized to tumor cells. Endothelial cells of tumor vessels were also immunoreactive for VEGF-B, probably representing the binding sites of the VEGF-B polypeptide secreted by adjacent tumor cells. VEGF-C mRNA was detected in approximately one-half of the cancers analyzed. Via in situ hybridization, VEGF-C mRNA was also localized to tumor cells. All lymphomas studied contained low levels of VEGF-C mRNA, possibly reflecting the cell-specific pattern of expression of the VEGF-C gene in the corresponding normal cells. The expression of VEGF-C is associated with the development of lymphatic vessels, and VEGF-C could be an important factor regulating the mutual paracrine relationships between tumor cells and lymphatic endothelial cells. Furthermore, VEGF-C and VEGF-B can, similarly to VEGF, be involved in tumor angiogenesis.

Proinflammatory cytokines regulate expression of the lymphatic endothelial mitogen vascular endothelial growth factor-C

Vascular endothelial growth factor (VEGF) is a prime regulator of normal and pathological angiogenesis. Three related endothelial cell growth factors, VEGF-B, VEGF-C, and VEGF-D were recently cloned. We have here studied the regulation of VEGF-C, a lymphatic endothelial growth factor, by angiogenic proinflammatory cytokines. Interleukin (IL)-1beta induced a concentration- and a time-dependent increase in VEGF-C, but not in VEGF-B, mRNA steady-state levels in human lung fibroblasts. The increase in VEGF-C mRNA levels was mainly due to increased transcription rather than elevated mRNA stability as detected by the nuclear run-on method and by following mRNA decay in the presence of an inhibitor of transcription, respectively. In contrast, angiopoietin-1 mRNA, encoding the ligand for the endothelial-specific Tek/Tie-2 receptor, was down-regulated by IL-1beta. Tumor necrosis factor-alpha and IL-1alpha also elevated VEGF-C mRNA steady-state levels, whereas the IL-1 receptor antagonist and dexamethasone inhibited the effect of IL-1beta. Experiments with cycloheximide indicated that the effect of IL-1beta was independent of protein synthesis. Hypoxia, which is an important inducer of VEGF expression, had no effect on VEGF-B or VEGF-C mRNA levels. IL-1beta and tumor necrosis factor-alpha also stimulated the production of VEGF-C protein by the fibroblasts. Cytokines and growth factors have previously been shown to down-regulate VEGF receptors in vascular endothelial cells. We found that the mRNA for the VEGF- and VEGF-C-binding VEGFR-2 (KDR/Flk-1) was stimulated by IL-1beta in human umbilical vein endothelial cells, whereas the mRNA levels of VEGFR-1 (Flt-1) and VEGFR-3 (Flt-4) were not altered. Our data suggest that in addition to VEGF, VEGF-C may also serve as an endothelial stimulus at sites of cytokine activation. In particular, these results raise the possibility that certain proinflammatory cytokines regulate the lymphatic vessels indirectly via VEGF-C.

Comparison of VEGF, VEGF-B, VEGF-C and Ang-1 mRNA regulation by serum, growth factors, oncoproteins and hypoxia

The vascular endothelial growth factor (VEGF) family has recently been expanded by the isolation of two additional growth factors, VEGF-B and VEGF-C. Here we compare the regulation of steady-state levels of VEGF, VEGF-B and VEGF-C mRNAs in cultured cells by a variety of stimuli implicated in angiogenesis and endothelial cell physiology. Hypoxia, Ras oncoprotein and mutant p53 tumor suppressor, which are potent inducers of VEGF mRNA did not increase VEGF-B or VEGF-C mRNA levels. Serum and its component growth factors, platelet-derived growth factor (PDGF) and epidermal growth factor (EGF) as well as transforming growth factor-beta (TGF-beta) and the tumor promoter phorbol myristate 12,13-acetate (PMA) stimulated VEGF-C, but not VEGF-B mRNA expression. Interestingly, these growth factors and hypoxia simultaneously downregulated the mRNA of another endothelial cell specific ligand, angiopoietin-1. Serum induction of VEGF-C mRNA occurred independently of protein synthesis; with an increase of the mRNA half-life from 3.5 h to 5.5-6 h, whereas VEGF-B mRNA was very stable (T 1/2>8 h). Our results reveal that the three VEGF genes are regulated in a strikingly different manner, suggesting that they serve distinct, although perhaps overlapping functions in vivo.