Effects of bariatric surgery on functional connectivity of the reward and default mode network: A pre-registered analysis

Obesity imposes serious health risks and involves alterations in resting‐state functional connectivity of brain networks involved in eating behavior. Bariatric surgery is an effective treatment, but its effects on functional connectivity are still under debate. In this pre‐registered study, we aimed to determine the effects of bariatric surgery on major resting‐state brain networks (reward and default mode network) in a longitudinal controlled design. Thirty‐three bariatric surgery patients and 15 obese waiting‐list control patients underwent magnetic resonance imaging at baseline, after 6 and 12 months. We conducted a pre‐registered whole‐brain time‐by‐group interaction analysis, and a time‐by‐group interaction analysis on within‐network connectivity. In exploratory analyses, we investigated the effects of weight loss and head motion. Bariatric surgery compared to waiting did not significantly affect functional connectivity of the reward network and the default mode network (FWE‐corrected p > .05), neither whole‐brain nor within‐network. In exploratory analyses, surgery‐related BMI decrease (FWE‐corrected p = .041) and higher average head motion (FWE‐corrected p = .021) resulted in significantly stronger connectivity of the reward network with medial posterior frontal regions. This pre‐registered well‐controlled study did not support a strong effect of bariatric surgery, compared to waiting, on major resting‐state brain networks after 6 months. Exploratory analyses indicated that head motion might have confounded the effects. Data pooling and more rigorous control of within‐scanner head motion during data acquisition are needed to substantiate effects of bariatric surgery on brain organization.

EGF and BMPs Govern Differentiation and Patterning in Human Gastric Glands

BACKGROUND & AIMS

The homeostasis of the gastrointestinal epithelium relies on cell regeneration and differentiation into distinct lineages organized inside glands and crypts. Regeneration depends on Wnt/β-catenin pathway activation, but to understand homeostasis and its dysregulation in disease, we need to identify the signaling microenvironment governing cell differentiation. By using gastric glands as a model, we have identified the signals inducing differentiation of surface mucus-, zymogen-, and gastric acid-producing cells.

METHODS

We generated mucosoid cultures from the human stomach and exposed them to different growth factors to obtain cells with features of differentiated foveolar, chief, and parietal cells. We localized the source of the growth factors in the tissue of origin.

RESULTS

We show that epidermal growth factor is the major fate determinant distinguishing the surface and inner part of human gastric glands. In combination with bone morphogenetic factor/Noggin signals, epidermal growth factor controls the differentiation of foveolar cells vs parietal or chief cells. We also show that epidermal growth factor is likely to underlie alteration of the gastric mucosa in the precancerous condition atrophic gastritis.

CONCLUSIONS

Use of our recently established mucosoid cultures in combination with analysis of the tissue of origin provided a robust strategy to understand differentiation and patterning of human tissue and allowed us to draw a new, detailed map of the signaling microenvironment in the human gastric glands.

Weight loss reduces head motion: Revisiting a major confound in neuroimaging

Head motion during magnetic resonance imaging (MRI) induces image artifacts that affect virtually every brain measure. In parallel, cross‐sectional observations indicate a correlation of head motion with age, psychiatric disease status and obesity, raising the possibility of a systematic artifact‐induced bias in neuroimaging outcomes in these conditions, due to the differences in head motion. Yet, a causal link between obesity and head motion has not been tested in an experimental design. Here, we show that a change in body mass index (BMI) (i.e., weight loss after bariatric surgery) systematically decreases head motion during MRI. In this setting, reduced imaging artifacts due to lower head motion might result in biased estimates of neural differences induced by changes in BMI. Overall, our finding urges the need to rigorously control for head motion during MRI to enable valid results of neuroimaging outcomes in populations that differ in head motion due to obesity or other conditions.

Bariatric Surgery and Brain Health-A Longitudinal Observational Study Investigating the Effect of Surgery on Cognitive Function and Gray Matter Volume

Dietary modifications leading to weight loss have been suggested as a means to improve brain health. In morbid obesity, bariatric surgery (BARS)-including different procedures, such as vertical sleeve gastrectomy (VSG), gastric banding (GB), or Roux-en-Y gastric bypass (RYGB) surgery-is performed to induce rapid weight loss. Combining reduced food intake and malabsorption of nutrients, RYGB might be most effective, but requires life-long follow-up treatment. Here, we tested 40 patients before and six months after surgery (BARS group) using a neuropsychological test battery and compared them with a waiting list control group. Subsamples of both groups underwent structural MRI and were examined for differences between surgical procedures. No substantial differences between BARS and control group emerged with regard to cognition. However, larger gray matter volume in fronto-temporal brain areas accompanied by smaller volume in the ventral striatum was seen in the BARS group compared to controls. RYGB patients compared to patients with restrictive treatment alone (VSG/GB) had higher weight loss, but did not benefit more in cognitive outcomes. In sum, the data of our study suggest that BARS might lead to brain structure reorganization at long-term follow-up, while the type of surgical procedure does not differentially modulate cognitive performance.

Improvement in self-reported eating-related psychopathology and physical health-related quality of life after laparoscopic sleeve gastrectomy: A pre-post analysis and comparison with conservatively treated patients with obesity

OBJECTIVE

The present study examined the effects of laparoscopic sleeve gastrectomy (LSG) on self-reported eating-related psychopathology and health-related quality of life (HRQoL). Outcomes of the LSG group were compared with a group of conservatively treated (CT) patients, who underwent a 1-year multimodal weight reduction group program that included dietary advice, physical exercise, psychoeducation, cognitive-behavioral therapy, training in Jacobson's progressive muscle relaxation, and social group support. The setting was a multidisciplinary obesity center.

METHOD

A sample of 103 patients with obesity were investigated using the Eating Disorder Inventory and the Short Form Health Survey before and, on average, 19 (±5) months after weight loss intervention. Thereof, 63 patients (age 45.6±10.9years, 71.4% females) underwent LSG, and 40 patients (age 50.6±11.3years, 77.5% females) underwent the CT program. Patients were assigned to either the surgical or the nonsurgical intervention group following clinical guidelines and patient preference.

RESULTS

In the LSG group, excess weight loss (%EWL) was 53.0±24.0%, and body mass index (BMI) decreased from 51.5±8.1 to 38.0±7.7kg/m². In the CT group, %EWL was 13.9±27.1%, and BMI decreased from 40.3±6.7 to 38.0±7.2kg/m². Significant improvements in eating-related psychopathology were observed in both groups. Although both groups had a similar BMI after the respective interventions, LSG patients reported significantly greater body satisfaction and substantial improvement in perceived physical health from a lower baseline level than CT patients.

DISCUSSION

In the second follow-up year, LSG was associated with greater weight loss from a higher baseline weight, and greater improvements in self-reported eating-related psychopathology and physical HRQoL compared with conservative treatment.

Overexpression of COP9 signalosome subunits, CSN7A and CSN7B, exerts different effects on adipogenic differentiation

The COP9 signalosome (CSN) is an essential regulator of cullin‐RING‐ubiquitin (Ub) ligases (CRLs), which ubiquitinate important cellular regulators and target them for degradation by the Ub proteasome system (UPS). The CSN exhibits deneddylating activity localized on subunit CSN5, which removes the ubiquitin‐like protein Nedd8 from the cullins of CRLs. CSN‐mediated deneddylation is an important step in the process of CRL remodeling, in which new substrate recognition units are incorporated into Ub ligases to meet changed requirements for proteolysis in cells. For instance, extensive CRL remodeling occurs during adipogenic differentiation when new CRL3s are formed. Diversification of CSN complexes during evolution is most likely another adaptation to meet different cellular requirements. Best known CSN variants are formed by different CSN subunit isoforms. For instance, in plant cells, isoforms have been identified for the MPN‐domain subunits CSN5 (CSN5A and CSN5B) and CSN6 (CSN6A and CSN6B) which form four distinct CSN variants. In mammalian cells CSN^CSN7A and CSN^CSN7B variants are generated by CSN7 isoforms. We demonstrate that the two variants coexist in human LiSa‐2 cells and in mouse embryonic fibroblasts. During adipogenic differentiation of LiSa‐2 cells CSN7B increases in parallel with an elevation of the total CSN complex. Permanent overexpression of Flag‐CSN7B but not of Flag‐CSN7A accelerates adipogenesis in LiSa‐2 cells indicating a specific function of the CSN^CSN7B variant in stimulating adipogenesis. Silencing of CSN7A as well as of CSN7B in LiSa‐2 cells and in mouse embryonic fibroblasts (MEFs) reduces adipogenic differentiation demonstrating that both CSN^CSN7A and CSN^CSN7B variants are involved in the process.

Changes in self-reported eating patterns after laparoscopic sleeve gastrectomy: a pre-post analysis and comparison with conservatively treated patients with obesity

BACKGROUND

Patients with severe obesity need to adapt to surgically induced changes in their eating behaviors to maintain treatment success.

OBJECTIVES

This study examined the effects of laparoscopic sleeve gastrectomy (LSG) on weight loss and on 3 dimensions of eating behavior, namely, cognitive restraint, disinhibition, and hunger. Outcomes of the LSG group were compared with a group of conservatively treated (CT) patients, who underwent a 1-year multimodal weight-reduction group program that included dietary advice, physical exercise, psychoeducation, cognitive-behavioral therapy, training in Jacobson's progressive muscle relaxation, and social group support.

SETTING

The study setting was a multidisciplinary obesity center located in a university hospital.

METHODS

A sample of 102 patients with obesity were investigated using the Three-Factor Eating Questionnaire before and, on average, 19 (±5) months after weight loss intervention. Of the 102 patients, 62 (age 45.8±10.8 years, 71% females) underwent LSG, and 40 patients (age 50.6±11.3 years, 77.5% females) underwent the CT program. Patients were assigned to either the surgical or the nonsurgical intervention group following clinical guidelines and patient preference.

RESULTS

In the LSG group, total weight loss was 25.9±11.0%, excess weight loss was 52.8±24.1%, and body mass index decreased from 51.4±8.1 to 38.0±7.8 kg/m². In the CT group, total weight loss was 5.4±10.6%, excess weight loss was 13.9±27.1%, and body mass index decreased from 40.3±6.7 to 38.0±7.2 kg/m². Significant improvements in self-reported eating behaviors were observed in both groups, that is, an increased cognitive restraint of eating, a decreased disinhibition of eating control, and a reduced degree of perceived hunger. In contrast, whereas Three-Factor Eating Questionnaire scores before weight loss intervention did not differ between groups, LSG patients reported significantly greater reductions in disinhibition and hunger than CT patients did after weight loss intervention. In both groups, greater weight loss was associated with decreased hunger sensations.

CONCLUSION

In the second follow-up year, LSG was associated with greater weight loss and greater improvements in self-reported eating behaviors compared with conservative treatment.

A novel human gastric primary cell culture system for modelling Helicobacter pylori infection in vitro

BACKGROUND AND AIMS

Helicobacter pylori is the causative agent of gastric diseases and the main risk factor in the development of gastric adenocarcinoma. In vitro studies with this bacterial pathogen largely rely on the use of transformed cell lines as infection model. However, this approach is intrinsically artificial and especially inappropriate when it comes to investigating the mechanisms of cancerogenesis. Moreover, common cell lines are often defective in crucial signalling pathways relevant to infection and cancer. A long-lived primary cell system would be preferable in order to better approximate the human in vivo situation.

METHODS

Gastric glands were isolated from healthy human stomach tissue and grown in Matrigel containing media supplemented with various growth factors, developmental regulators and apoptosis inhibitors to generate long-lasting normal epithelial cell cultures.

RESULTS

Culture conditions were developed which support the formation and quasi-indefinite growth of three dimensional (3D) spheroids derived from various sites of the human stomach. Spheroids could be differentiated to gastric organoids after withdrawal of Wnt3A and R-spondin1 from the medium. The 3D cultures exhibit typical morphological features of human stomach tissue. Transfer of sheared spheroids into 2D culture led to the formation of dense planar cultures of polarised epithelial cells serving as a suitable in vitro model of H. pylori infection.

CONCLUSIONS

A robust and quasi-immortal 3D organoid model has been established, which is considered instrumental for future research aimed to understand the underlying mechanisms of infection, mucosal immunity and cancer of the human stomach.

Determinants of Weight Loss following Laparoscopic Sleeve Gastrectomy: The Role of Psychological Burden, Coping Style, and Motivation to Undergo Surgery

BACKGROUND

The amount of excess weight loss (%EWL) among obese patients after bariatric surgery varies greatly. However, reliable predictors have not been established yet. The present study evaluated the preoperative psychological burden, coping style, and motivation to lose weight as factors determining postoperative treatment success.

METHODS

The sample included 64 morbidly obese patients with a preoperative BMI of 51 ± 8 kg/m(2) who had undergone laparoscopic sleeve gastrectomy (LSG). Well-established questionnaires were applied before surgery to assess the psychological burden in terms of "perceived stress" (PSQ-20), "depression" (PHQ-9), "anxiety" (GAD-7), and "mental impairment" (ISR) as well as coping style (Brief COPE) and motivation to lose weight. %EWL as an indicator for treatment success was assessed on average 20 months after surgery.

RESULTS

Based on the %EWL distribution, patients were classified into three %EWL groups: low (14-39%), moderate (40-59%), and high (60-115%). LSG patients with high %EWL reported significantly more "active coping" behavior prior to surgery than patients with moderate and low %EWL. Patients' preoperative psychological burden and motivation to lose weight were not associated with %EWL.

CONCLUSION

An "active coping" style might be of predictive value for better weight loss outcomes in patients following LSG intervention.

[Procedure selection and technique of metabolic surgery]

Metabolic surgery is becoming an impressive therapeutic option for type 2 diabetes mellitus and other metabolic diseases. Compared to conservative therapy bariatric procedures, such as gastric bypass, sleeve gastrectomy, gastric banding and biliopancreatic diversion, seem to achieve significantly higher remission rates and improvements in blood glucose metabolism. Recent studies describe additional effect mechanisms which go beyond the assumed mechanisms of restriction and malabsorption. The results in the current literature suggest that gastric bypass and sleeve gastrectomy provide the best metabolic risk-benefit profiles. Gastric banding and biliopancreatic diversion can only be recommended in specific cases.

Ghrelin and NUCB2/nesfatin-1 are expressed in the same gastric cell and differentially correlated with body mass index in obese subjects

The orexigenic peptide ghrelin and the anorexigenic peptide nesfatin-1 are expressed by the same endocrine cell of the rat stomach, the X/A-like cell. However, data in humans are lacking, especially under conditions of obesity. We collected gastric tissue of obese patients undergoing sleeve gastrectomy and investigated the expression of nesfatin-1 and ghrelin in the gastric oxyntic mucosa by immunofluorescence. Nesfatin-1 immunoreactivity was detected in the human oxyntic mucosa in cells with an endocrine phenotype. A major portion of nesfatin-1 immunoreactive cells (78 %) co-localized with ghrelin indicating the occurrence in human X/A-like cells. In patients with very high body mass index (BMI 55-65 kg/m(2)), the number of nesfatin-1 immunoreactive cells/low-power field was significantly higher than in obese patients with lower BMI (40-50 kg/m(2), 118 ± 10 vs. 82 ± 11, p < 0.05). On the other hand, the number of ghrelin immunoreactive cells was significantly reduced in obese patients with higher compared to lower BMI (96 ± 12 vs. 204 ± 21, p < 0.01). Also the ghrelin-acylating enzyme ghrelin-O-acyltransferase decreased with increasing BMI. In conclusion, nesfatin-1 immunoreactivity is also co-localized with ghrelin in human gastric X/A-like cells giving rise to a dual role of this cell type with differential effects on stimulation and inhibition of appetite dependent on the peptide released. The expression of these two peptides is differentially regulated under obese conditions with an increase of nesfatin-1 and a decrease of ghrelin immunoreactivity with rising BMI pointing towards an adaptive change of expression that may counteract further body weight increase.

The COP9 signalosome, cullin 3 and Keap1 supercomplex regulates CHOP stability and adipogenesis

Obesity is one of the most serious health problems of the 21^st century. It is associated with highly increased risk of type 2 diabetes, high blood pressure, cardiovascular disease as well as several cancers. The expansion of the fat tissue needs the differentiation of preadipocytes to adipocytes, a process called adipogenesis. Dysfunction of adipogenesis is a hallmark of obesity and delineation of underlying mechanisms has high priority for identifying targets for pharmacological intervention. Here we investigate the impact of the COP9 signalosome (CSN), a regulator of cullin-RING ubiquitin ligases (CRLs), and of C/EBP homologous protein (CHOP) on the differentiation of LiSa-2 preadipocytes. CHOP induced by piceatannol or by permanent overexpression in LiSa-2 cells blocks adipocyte differentiation as characterized by inhibited fat droplet formation and vascular endothelial growth factor (VEGF) production. Knockdown of the CSN by permanent downregulation of CSN1 in LiSa-2 cells elevates CHOP and retards adipogenesis. The effect of the CSN knockdown on CHOP stability can be explained by the protection of the CRL component Keap1 by the CSN associated ubiquitin-specific protease 15 (USP15). Pulldowns and glycerol gradients reveal that CHOP interacts with a supercomplex consisting of the CSN, cullin 3 and Keap1. Transient knockdown of Keap1 increases CHOP steady state level and retards its degradation. We conclude that CHOP stability is controlled by a CSN-CRL3^Keap1 complex, which is crucial for adipogenesis. Our data show that CHOP is a distinguished target for pharmacological intervention of obesity.

Nissen versus Dor fundoplication for treatment of gastroesophageal reflux disease: a blinded randomized clinical trial

INTRODUCTION

Fundoplication techniques for treatment of gastroesophageal reflux are discussed concerning impairments and success. This randomized trial was conducted to compare Nissen's wrap and the anterior partial technique (Dor) concerning patients' quality of life (QoL) and functional data after a mid-term follow-up.

METHODS

In a 24-month period, 64 patients were equally randomized into group A (Nissen's fundoplication) and group B (180° anterior partial fundoplication). After a mean follow-up of 18 months, all patients were examined and interviewed using standardized QoL questionnaires (Gastrointestinal Quality of Life Index), Visick score, 24-hour pH-metry and esophageal manometry. Data of 57 patients (group A: 27, group B: 30) could be analyzed.

RESULTS

After partial fundoplication, 9 patients (30%) stated the operative results were worse than perfect. Only 2 patients (7%) evaluated the outcome after Nissen's fundoplication as unsuccessful (p = 0.04). However, postoperative Gastrointestinal Quality of Life Index showed no differences between groups (p = 0.5). Additionally, functional data were not different (DeMeester 10 vs. 12, p = 0.17, and lower esophageal sphincter pressure 13 vs. 12 mm Hg, p = 0.5).

CONCLUSION

The anterior partial fundoplication technique did not lead to disadvantages in postoperative QoL, physiological function and reflux control when compared to Nissen's approach in a mid-term follow-up.

[Demands of private gastroenterologists for collaborative treatment concepts with clinics. Results of a Germany-wide survey]

BACKGROUND

New demands and possibilities of collaboration between hospitals and private practices in Germany have appeared, now that the way has been opened legally. A poll was conducted to analyse the current status of collaboration between outpatient gastroenterologists and hospital surgical departments and to identify possible future collaborations.

MATERIALS AND METHODS

One thousand twenty-six private practices specialising in endoscopy were found by contacting the Association of Statutory Health Insurance Physicians and additional internet research. Of these, 50% were randomly selected (513 private practices) and contacted by mail with anonymous questionnaires about cooperation with their clinical partners. Two hundred three (39.6%) practices responded, of which 200 could be analysed.

RESULTS

Of all practices reached, 75% considered the cooperation with clinics very valuable or even exceptional. Still, almost half (46%) suggested necessary improvements in these collaborations. Around a third of all contacted colleagues were already involved in projects following integrated care models. In about 80% of all participants, the main interest in integrated models was specified to be common therapy planning.

CONCLUSION

The data analysis of this study shows a substantial interest of private-practice gastroenterologists in close collaboration with hospitals. It is now up to the hospitals to open contracts with their medical outpatient partners.

Einfluss des Pneumoperitoneums auf die Expression von E-Cadherin, CD44v6 und CD54 (ICAM-1) auf HT-29-Kolonkarzinomzellen

INTRODUCTION

The mechanism of potential tumor cell spread and growth during laparoscopy is poorly understood. Nevertheless, different experimental studies reported a stimulation of tumor cell growth and an increased metastatic potential of carcinoma cells using carbon dioxide as an insufflation medium. Adhesion molecules do play an important and regulatory function in the process of metastatic spread and invasion of cancer cells. Therefore we investigated the influence of CO2 and Helium insufflation on the in-vitro expression of E-Cadherin, CD44v6 and CD54 (ICAM-1) on HT-29 colon carcinoma cells.

METHODS

HT-29 carcinoma cells were exposed to either CO2 or helium insufflation. Expression of E-Cadherin, CD44v6 and CD54 (ICAM-1) on HT-29 colon carcinoma cells were measured 1, 12, 24, 48 and 96 h after CO2 and helium insufflation using flowcytometry (FACScan). Data were analyzed by Friedman-test.

RESULTS

HT-29 cell line showed a short decrease in E-Cadherin expression after CO2 exposure while helium insufflation had no influence. In contrasts to these findings the expression of CD44v6 and CD54 on HT-29 cells were not influenced significantly by either CO2 or helium.

CONCLUSION

CO2 seems only to have a minor influence on the expression of E-Cadherin while expression of other adhesion molecules did not change after CO2 incubation. The alternative gas helium did not cause any significant changes of the expression of either E-Cadherin, CD44v6 and CD54. Further investigations are needed to elucidate the changes of the metastatic potential of tumor cells after laparoscopic and open procedures.

Morphology of the rat peritoneum after carbon dioxide and helium pneumoperitoneum: a scanning electron microscopic study

BACKGROUND

Laparoscopic surgery for patients with cancer has been debated because of the susceptibility that laparoscopic incisions have shown for metastatic tumor growth. Structural damage of the mesothelial layer attributable to the pneumoperitoneum may facilitate intraabdominal tumor cell adhesion and growth. The influence of carbon dioxide (CO(2)) and helium pneumoperitoneum on the morphology of the peritoneum was examined.

METHODS

A total of 50 rats received colon carcinoma (DHB/TRb) cells intraperitoneally and CO(2) (n = 25) or helium (n = 25) pneumoperitoneum at 15 mmHg for 15 min. After different periods (2, 12, 24, 48, and 96 h), the rats were killed, and the peritoneum was examined by scanning electron microscopy. Control animals (n = 5) were without pneumoperitoneum.

RESULTS

The control animals and most of the rats with pneumoperitoneum showed no peritoneal alterations. In four animals of each group, inflammatory alterations of the peritoneum such as bulging and retraction of mesothelial cells were observed at different time points. Tumor cells adherent to the peritoneum were found in a total of six animals. Peritoneal carcinomatosis, tumor nodules, or infiltration of the peritoneum by tumor cells was not observed.

CONCLUSIONS

The study demonstrated that the morphologic integrity of the rat peritoneum is not disturbed when CO(2) or helium is used for insufflation combined with the intraperitoneal injection of carcinoma cells. Pneumoperitoneum therefore probably is not the condition causing peritoneal changes that favor intraperitoneal tumor growth.

Laparoscopic removal of ingested pin penetrating the gastric wall in an immunosuppressed patient

Foreign body ingestion is a well-recognized and relative common problem. Most foreign bodies pass spontaneously and uneventfully through the digestive tract. In some cases, however, the ingestion of foreign bodies is associated with a high risk of complications because of their size or shape or the hosts medical status. We report a case of successful laparoscopic removal of an accidentally ingested pin that was penetrating the anterior gastric wall in a immunosuppressed patient. After removal of the pin, the opening of the gastric wall was closed with an extracorporeal hand-suturing technique. The patient recovered uneventfully and was discharged in good health on the 5th day after the procedure. Laparoscopy should be considered the approach of choice for the removal of ingested foreign bodies when surgery is indicated.

Local and systemic chemotherapy with taurolidine and taurolidine/heparin in colon cancer-bearing rats undergoing laparotomy

Experimental studies in the therapy of malignant abdominal tumors have shown that different cytotoxic agents suppress the intraperitoneal tumor growth. Nevertheless, a general accepted approach to prevent tumor recurrences does not exist. Following subcutaneous and intraperitoneal injection of 10(4) colon adenocarcinoma cells (DHD/K12/TRb), the influences of both taurolidine or taurolidine/heparin on intraperitoneal and subcutaneous tumor growth was investigated in 105 rats undergoing midline laparotomy. The animals were randomized into 7 groups and operated on during 30 min. To investigate the intraperitoneal (local) influence of either taurolidine or heparin on tumor growth, the substances were applied intraperitoneally. Systemic and intraperitoneal effects were evaluated after intravenous injection of the substances. Both application forms were also combined to analyze synergistic effects. Tumor weights, as well as the incidence of abdominal wound metastases, were determined four weeks after the intervention. In order to evaluate the effects of the agents, blood was taken to determine the peripheral leukocytes counts. Intraperitoneal tumor growth in rats receiving intraperitoneal application of taurolidine (median 7.0 mg, P = 0.05) and of taurolidine/heparin (median 0 mg, P = 0.02) was significantly reduced when compared to the control group (median 185 mg). The simultaneous instillation of both agents also reduced the intraperitoneal tumor growth (median 4 mg, P = 0.04), while the intravenous injection of the substances caused no local effect. In contrast, the subcutaneous tumor growth did not differ among all groups. In all groups, abdominal wound recurrences were rare and did not differ. Independent of the agents and the application form, the operation itself caused a slight leukopenia shortly after the operation and a leukocytosis in the following course. Intraperitoneal therapy of either taurolidine or in combination with heparin inhibits local tumor growth and abdominal wound recurrences in rats undergoing midline laparotomy. Neither the intraperitoneal nor the intravenous application or the combination of the two agents influenced the subcutaneous tumor growth. The substances did not alter the changes of peripheral leukocytes.

Isolated amyloid tumor in the mediastinum: report of a case

Primary amyloidosis isolated in the mediastinum is rarely encountered in thoracic surgery and few such cases have been reported. We present a case of primary isolated hilar amyloidosis of the mediastinum to illustrate the difficulties in differentiating this disorder preoperatively from central bronchial carcinoma, carcinoid tumor, and mediastinal lymphoma. Usually, a definitive diagnosis can only be made by open biopsy during thoracoscopy or thoracotomy. In conclusion, amyloidosis should be considered in the differential diagnosis of patients when calcifications are found, bearing in mind that radiologic findings are inconclusive and transbronchial biopsy can be negative.

Influence of intraperitoneal and systemic application of taurolidine and taurolidine/heparin during laparoscopy on intraperitoneal and subcutaneous tumour growth in rats

BACKGROUND

Recent clinical and experimental studies investigated the problem and possible pathomechanisms of portsite metastases after laparoscopic resection of malignant tumours. A generally accepted approach to prevent these tumour implantations does not exist so far.

METHODS

After subcutaneous and intraperitoneal injection of 10(4) cells of colon adenocarcinoma (DHD/K12/TRb) the influences of either taurolidine or taurolidine/heparin on intraperitoneal and subcutaneous tumour growth were investigated in 105 rats undergoing laparoscopy with carbon dioxide. The animals were then randomised into seven groups. A pneumoperitoneum was established using carbon dioxide for 30 min (8 mmHg). Three incisions were used: median for the insufflation needle, and a right and left approach in the lower abdomen for trocars. To investigate the intraperitoneal (local) influence of either taurolidine and heparin on tumour growth the substances were instilled intraperitoneally. Systemic effects were expected when the substances were applied intravenously (iv). Synergistic influences were tested when both application forms were combined. The number and the weight of tumours as well as the incidence of abdominal wall and port-site metastases were determined four weeks after intervention. Blood was taken to evaluate the influences of taurolidine and heparin on systemic immunologic reactions: seven days before laparoscopy. two hours, two days. seven days, and four weeks after operation, and the peripheral lymphocytes were determined.

RESULTS

Intraperitoneal (ip) tumour weight in rats receiving taurolidine (median 7 mg) and taurolidine/heparin (0 mg) intraperitoneally was significantly reduced when compared to the control group (52 mg) (P = 0.001). There was no difference of subcutaneus tumour growth among the groups (P = 0.4). Trocar recurrences were decreased when taurolidine was applied ip (3115). ipiv (4/15), and ip in combination with heparin (4/15) in comparison to the control group (10/15). Immediately after intervention treated and untreated groups showed a peripheral lymphopenia.

CONCLUSIONS

The intraperitoneal therapy with taurolidine and the combination with heparin inhibits the intraperitoneal tumour growth and trocar recurrences. Neither the intraperitoneal nor the systemic application or the combination of taurolidine and heparin did reduce the subcutaneous tumour growth. The intervention caused a lymphopenia which was compensated on day two.

Immunomodulatory changes in patients with colorectal cancer

BACKGROUND AND AIMS

Solid tumors are frequently accompanied by a depressed cellular and humoral immunity. This study analyzed changes these factors in colorectal cancer patients.

PATIENTS AND METHODS

We compared cellular (leukocytes, lymphocytes, HLA-DR expression on monocytes) and humoral immune parameters (interleukin-6, interleukin-10, tumor necrosis factor alpha) in 40 patients with colorectal cancer and in 18 healthy controls.

RESULTS

Leukocytes were in the normal range in patients and controls. However, tumor patients showed significant lymphopenia in comparison to controls. HLA-DR antigen expression on CD14+ monocytes was reduced in the cancer patients while IL-6 and IL-10 plasma levels were increased. Patients with UICC stage III had IL-6 and IL-10 concentrations were significantly increased as well.

CONCLUSIONS

These findings suggest that colorectal tumor establishment and progression results in a malfunction of the immune system, and underline the importance of elucidating in detail the mechanisms of immune modulation in cancer patients.

Cellular and humoral inflammatory response after laparoscopic and conventional colorectal resections

BACKGROUND

Surgical trauma and anesthesia are known to cause transient postoperative suppression of the immune system. In randomized controlled trials, it has been shown that laparoscopic colorectal resections have short-term benefits not observed with conventional colorectal resections. We hypothesized that these benefits were due to the reduction in surgical trauma, leading to a diminished cytokine response and less depression of cell-mediated immunity after laparoscopy.

METHODS

In a prospective randomized trial, colorectal cancer patients without evidence of metastatic disease underwent either laparoscopic (n = 20) or conventional (n = 20) tumor resection. Postoperative immune function was assessed by measuring the white blood cell (WBC) count, the CD4+ and CD8+ lymphocytes, the CD4+/CD8+/ratio, and the HLA-DR expression of CD14+ monocytes. In addition, the production of interleukin-6 (IL = 6) and TNF-a were measured after ex vivo stimulation of mononuclear blood cells with lipopolysaccharide (LPS) and compared to the plasma levels of these cytokines. Postoperative mean levels of the immunologic parameters for the two groups were calculated and compared using the Mann-Whitney U test.

RESULTS

Preoperatively, there were no differences between the two groups in terms of patient characteristics or immunologic parameters. Although the postoperative peak concentrations of white blood cells were significant lower in the laparoscopic group than the conventional group (p < 0.05), there were no differences between the two groups in the subpopulation of lymphocytes (CD4+, CD8+). HLA-DR expression of CD14+ monocytes was lower in the conventional group on the 4th postoperative day (p < 0.05). The laparoscopic group showed higher values in cytokine production of mononuclear blood cells after LPS stimulation. Postoperative plasma peak concentrations of IL-6 and TNF-a were lower after laparoscopic resection.

CONCLUSION

Postoperative cell-mediated immunity was better preserved after laparoscopic than after conventional colorectal resection. Cellular cytokine production was preserved only in the laparoscopic group, while cytokine plasma levels were significantly higher in the conventional group. These findings may have important implications for the use of laparoscopic colorectal resection, especially in patients with malignant disease.

Cardiopulmonary changes during laparoscopy and vessel injury: comparison of CO2 and helium in an animal model

BACKGROUND

Injury of venous vessels during elevated intraperitoneal pressure is thought to cause possible fatal gas embolism, and helium may be dangerous because of its low solubility.

METHODS

Twenty pigs underwent laparoscopy with either CO2 (n=10) or helium (n=10) with a pressure of 15 mm Hg and standardized laceration (1 cm) of the vena cava inferior. After 30 s, the vena cava was clamped, closed endoscopically by a running suture and unclamped again. During the procedure changes of cardiac output (CO), heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), pulmonary artery pressure (PAP), pulmonary artery wedge pressure (PAWP), end tidal CO2 pressure (PETCO2), and arterial blood gas analyses (pH, pO2 and pCO2) were investigated.

RESULTS

No animal died during the experimental course (mean blood loss during laceration: CO2, 157+/-50 ml; helium, 173+/-83 ml). MAP and CO values showed a decrease after laceration of the vena cava in both groups that had already been completely compensated for before suturing. PETCO2 increased significantly after CO2 insufflation (P<0.01), while helium showed no effect. Laceration of the vena cava caused no significant changes in PETCO2 values in either group. Significant acidosis and an increase of pCO2 were only found in the CO2 group.

CONCLUSIONS

The incidence of gas embolism during laparoscopy and accidental vessel injury seems to be very low. With the exception of acidosis and an increase of PETCO2 in the CO2 group, there were no differences in cardiopulmonary function between insufflation of CO2 and helium.

The impact of laparoscopy with carbon dioxide versus helium on immunologic function and tumor growth in a rat model

BACKGROUND

The pathogenesis of port site recurrences after laparoscopic surgery for malignant disease is still unknown. Whether different gases used to establish pneumoperitoneum have an influence on immunologic function and therefore on promotion of tumor growth has not yet been investigated.

METHODS

Tumor growth of colon adenocarcinoma DHD/K12/TRb was evaluated in a rat model after insufflation either with CO2 (n = 25) or helium (n = 25) and in a control group (n = 25). Tumor growth was measured subcutaneously and intraperitoneally 5 weeks after insufflation. Beside tumor growth, immunologic changes (peripheral leukocyte subpopulations, plasma levels of TNFalpha and IL-10) were evaluated during the perioperative course in all animals.

RESULTS

Subcutaneous tumor growth was promoted by the CO2 (99 +/- 55 mg; p < 0.01) compared to the helium (40 +/- 41 mg) and control groups (36 +/- 33 mg). Total intraperitoneal tumor weight was 718 +/- 690 mg in the CO2 group compared to the helium (549 +/- 233 mg) and control groups (521 +/- 221 mg). While peripheral leukocyte subpopulations only differed between the laparoscopic groups and the control group during the perioperative course, TNFalpha plasma levels were significantly decreased and IL-10 plasma levels significantly increased in the CO2 group compared to the helium and control groups in the postoperative course.

CONCLUSION

The insufflation of CO2 promotes tumor growth compared to the helium and control groups in a rat model. In addition, increased tumor growth was associated with a significant increase in IL-10 and a decrease in TNFalpha plasma levels.

New therapeutic strategies to avoid intra- and extraperitoneal metastases during laparoscopy: results of a tumor model in the rat

BACKGROUND

Therapeutic strategies to prevent port site recurrences in laparoscopy surgery of malignancies have not been investigated until now.

METHODS

The effects of taurolidine, heparin, and povidone iodine on the growth of rat and human colon adenocarcinoma as well as gallbladder carcinoma were investigated in vitro. Furthermore, cytokine release of growth-stimulating IL-1beta by peritoneal macrophages was measured after incubation with carbon dioxide and additional incubation with the different agents. In the third experiment, prevention of intra- and extraperitoneal metastases by intraperitoneal instillation of the different agents during laparoscopy was investigated in a colon carcinoma model in the rat. Tumor cells were administered intraperitoneally in 100 rats, and pneumoperitoneum (8 mm Hg) was established over 30 min with carbon dioxide. Rats received either tumor cells, cells + heparin, cells + povidone iodine, cells + taurolidine, or cells + taurolidine + heparin.

RESULTS

In vitro, tumor cell growth decreased after incubation with taurolidine, taurolidine/heparin, and povidone iodine. Cytokine release was stimulated by incubation with carbon dioxide and could only be suppressed by incubation with taurolidine in vitro. In vivo, intraperitoneal tumor weight was lower in rats receiving heparin (251 +/- 153 mg) and povidone iodine (134 +/- 117 mg) compared to the control group (541 +/- 291 mg), but even less when taurolidine (79 +/- 82 mg) or taurolidine/heparin (18.3 +/- 30 mg) were instilled.

CONCLUSION

Heparin slightly inhibits intraperitoneal tumor growth in vivo, while povidone iodine and taurolidine cause a significant decrease in tumor cell growth in vitro as well as intraperitoneal tumor growth in vivo. Cytokine release of peritoneal macrophages is only suppressed by taurolidine. Total tumor take and trocar metastases are only suppressed by taurolidine and taurolidine/heparin.

Impact of laparoscopy with carbon dioxide versus helium on local and systemic inflammation in an animal model of peritonitis

Increased intraperitoneal pressure and insufflation of carbon dioxide during laparoscopy may cause sepsis by promoting systemic inflammation in patients with intra-abdominal inflammatory diseases. The influence of carbon dioxide and helium during laparoscopy on bacteremia, endotoxemia, the plasma concentration of tumor necrosis factor-alpha (TNF-alpha), TNF-alpha secretion ex vivo by peripheral blood mononuclear cells (PBMCs), and intraperitoneal abscess formation was investigated in an animal model. A standardized fecal inoculum was injected intraperitoneally, and rats underwent laparoscopy with either carbon dioxide (N = 20) or helium (N = 20) or no further manipulation (control group; N = 20). Bacteremia was significantly more common 1 hour after laparoscopy with CO2 than in animals receiving helium or the control group. Furthermore, helium use led to a significant decrease of bacteremia 1 week after intervention. Fecal inoculation caused significant leukocytopenia in all groups within 1 hour after intervention, with complete recovery only in the helium-treated group (p < 0.05). The TNF-alpha plasma concentration was significantly lower in the helium-treated group, and suppression of ex vivo production recovered only in the animals undergoing laparoscopy with helium (p < 0.05). The number of intraperitoneal abscesses was significantly lower after laparoscopy with helium (2+/-1.5) than after CO2 laparoscopy (6.3+/-5.1) or in the control group (5.2+/-4.8). Laparoscopy with CO2 increased systemic inflammation only slightly, while helium use was associated with a significant lower incidence of bacteremia and local and systemic inflammation compared with the control group.

[The influence of alanyl-glutamine on immunologic functions and morbidity in postoperative total parenteral nutrition. Preliminary results of a prospective randomized trial]

Glutamine seems to play an important role in metabolism and function of immunologic cells and therefore could also influence postoperative immunosuppression in surgical patients. Nevertheless, the influence of glutamine substitution in postoperative total parenteral nutrition on immunologic function and postoperative morbidity of patients is still unknown. Therefore, the impact of glutamine substitution on postoperative immunosuppression and incidence of complications was investigated in patients with surgical interventions on esophagus or stomach and total parenteral nutrition in a prospective randomized trial. To analyse the immunologic competence of the patients, the expression of CD-3, CD-4, and CD-8 on lymphocytes as well as the expression of HLA-DR and CD-14 on monocytes were evaluated before, 1, 2, 4, 7 days after surgery. Furthermore, plasma levels of IL-6 and IL-10 were analysed during the perioperative course. Actually, 34 patients have been included (with glutamine: n = 18 vs. without glutamine: n = 16) in the study. Patients with glutamine substitution showed non significantly decreased systemic inflammation (IL-6-plasma levels, leucocytosis) and significantly faster compensation of postoperative immunosuppression (HLA-DR-monocytes). Incidence of postoperative complications was decreased after glutamine substitution compared with the control group. Patients without postoperative complications showed no significant difference in postoperative immunosuppression. Although additional substitution of the amino acid glutamine might possibly decrease incidence of postoperative complications in patients with total parenteral nutrition a general advantage in postoperative immune function could not be demonstrated.

[Effect of alanyl-glutamine in postoperative total parenteral nutrition on postoperative immunosuppression and morbidity. Preliminary results of a prospective randomized study]

The impact of glutamine substitution on postoperative immunosuppression and morbidity was investigated in patients with surgical interventions and total parenteral nutrition in a prospective randomized trial. To analyze immune competence, the expression of CD3, CD4, and CD8 on lymphocytes and of HLA-DR and CD14 on monocytes as well as the plasma levels of IL-6 and IL-10 was evaluated before, 1, 2, 4, and 7 days after surgery. A total of 34 patients have been included (with glutamine: n = 18; without glutamine: n = 16). Patients with glutamine substitution showed decreased systemic inflammation, significant faster compensation for postoperative immunosuppression and a lower incidence of postoperative complications. Patients without postoperative complications showed no significant differences in postoperative immunosuppression.

[Perioperative immunomonitoring in stomach carcinoma--useful diagnostic supplementary test for detecting patients at risk for complications?]

Early detection of postoperative complications before clinical signs occur seems to be possible by perioperative immunologic monitoring. Patients with insufficiency of the anastomosis after gastrectomy showed a significant increase in anti-inflammatory cytocine IL-10 already 4 h after operation.

Experimental study of the effect of intra-abdominal pressure during laparoscopy on tumour growth and port site metastasis

BACKGROUND

The influence of raised intraperitoneal pressure during laparoscopy on tumour growth and port site metastasis is still unknown.

METHODS

Tumour growth of colonic adenocarcinoma DHD/K12/TRb was measured after laparoscopy with carbon dioxide at different pressures (0, 5, 10 and 15 mmHg) in a rat model. Cell kinetics were determined after incubation with carbon dioxide (0, 5, 10 and 15 mmHg) in vitro (n=60). Additionally, tumour growth was measured subcutaneously and intraperitoneally 4 weeks after laparoscopy at different intraperitoneal pressures (5, 10 and 15 mmHg) (n=100).

RESULTS

In vitro tumour growth decreased significantly after incubation with carbon dioxide at 10 and 15 mmHg compared with a pressure of 0 or 5 mmHg. In vivo, mean(s.d.) intraperitoneal tumour weight was significantly increased after laparoscopy at 5 mmHg (919(1085) mg) and at 10 mmHg (1274(1523) mg) (P< 0.05), but decreased again after laparoscopy with an intraperitoneal pressure of 15 mmHg (731(929) mg) compared with the control group (365(353) mg) (P=0.3). Mean(s.d.) subcutaneous tumour growth was promoted after laparoscopy at 5 mmHg (172(234) mg), at 10 mmHg (190(253) mg) and at 15 mmHg (178(194) mg) compared with controls (48(33) mg) (P < 0.05).

CONCLUSION

In vitro, raised intraperitoneal pressure leads to suppression of tumour growth. In vivo, intraperitoneal tumour growth is suppressed only by higher pressure (15 mmHg). Subcutaneous tumour growth is stimulated by carbon dioxide independently of the intraperitoneal pressure.

Increased systemic inflammation after laparotomy vs laparoscopy in an animal model of peritonitis

OBJECTIVE

To study the influence of laparotomy and laparoscopy on local and systemic inflammation in a rat model of peritonitis.

DESIGN

Bacteremia, peripheral leukocyte subpopulations, tumor necrosis factor alpha (TNF-alpha) plasma levels, and ex vivo secretion of peripheral blood mononuclear cells were investigated after laparotomy and laparoscopy in a prospective randomized experimental study.

SETTING

Surgical department of a university hospital.

ANIMALS

60 male inbred Wistar rats.

INTERVENTIONS

Standardized fecal inoculum was injected intraperitoneally and rats underwent laparotomy (n=20), laparoscopy (n=20), or no further manipulation (control group, n=20). Blood samples were obtained during the perioperative course to determine bacteremia, leukocytic subpopulations, TNF-alpha plasma levels, and ex vivo secretion. The number of intraperitoneal abscesses was determined in each animal after 1 week.

MAIN OUTCOME MEASURE

The hypothesis of the experiment was that laparoscopy with carbon dioxide leads to an increase of local and systemic inflammation in comparison with the laparotomy and control groups.

RESULTS

One hour after intervention, bacteremia was significantly higher in the laparotomy and laparoscopy groups compared with the control group (P=.01). Fecal inoculum caused significant monocytopenia and lymphocytopenia in all groups within 1 hour after intervention (P<.05), with complete recovery on day 2 only in the laparoscopy and control groups. Laparotomy caused a significant increase in TNF-alpha plasma levels and decrease of ex vivo production of TNF-alpha compared with the other 2 groups (P<.05).

CONCLUSIONS

Laparotomy and laparoscopy increased the incidence of bacteremia and systemic inflammation in this peritonitis model. The inflammatory response was significantly higher in the laparotomy group compared with the laparoscopy group.

[Effect of splenectomy on intra- and extraperitoneal tumor growth with reference to the immune system in a rat model]

In this model, splenectomy does not significantly influence the intra- and extraperitoneal tumor growth. Although the spleen accounts 25% of the cellular immune capacity, we found no difference in pro- or antiinflammatory cytokines but a significant increase of the white blood count after splenectomy compared with the control group. The influence of splenectomy on growth of intraperitoneal disseminated tumor cells must be investigated in further studies.

[Effect of intra-abdominal pressure in laparoscopy on intraperitoneal tumor growth and development of trocar metastases. An animal experiment study in the rat model]

The results of the study indicate that elevated pressure during gas incubation in vitro leads to suppression of tumor growth probably due to direct damage of the cells. In vivo, laparoscopy with carbon dioxide and slightly elevated intraperitoneal pressure (5 and 10 mmHg) leads to promotion of intraperitoneal tumor growth while higher pressure (15 mmHg) causes again suppression of intraperitoneal tumor growth. Subcutaneous tumor growth is stimulated by carbon dioxide insufflation in all groups with elevated intraperitoneal pressures. The hypothesis that elevated intraperitoneal pressure might influence the immune system of the tumor host and increase immune suppression after laparoscopy remains theoretically and has to be investigated in further studies.

[Peritoneal instillation of taurolidine and heparin for preventing intraperitoneal tumor growth and trocar metastases in laparoscopic operations in the rat model]

BACKGROUND

Although port-site metastases occur after laparoscopic surgery, there is no generally accepted approach to prevent tumor implantation so far.

METHODS

In order to prevent tumor metastases, the effect of taurolidine and heparin on the growth of colon adenocarcinoma DHD/K12/TRb was measured in vitro and in a rat model. After incubation of the cells with heparin, taurolidine or both substances, the cell kinetics were determined. In a second experiment, tumor cells were administered intraperitoneally in rats (n = 60) and pneumoperitoneum was established over 30 min. Rats were randomized into four groups (I: tumor cells; II: cells + heparin; III: cells + taurolidine; IV: cells + taurolidine + heparin).

RESULTS

While tumor cell growth was not influenced by heparin in vitro, growth decreased significantly after incubation with taurolidine and taurolidine/heparin. In vivo, intraperitoneal tumor weight was lower in rats receiving heparin (298 +/- 155 mg) and taurolidine (149 +/- 247 mg) than in the control group (596 +/- 278 mg). When the two substance were combined, tumor growth was even less (21.5 +/- 36 mg). Trocar metastases were only lower in rats receiving taurolidine or the combination of taurolidine and heparin.

CONCLUSION

In vivo, heparin inhibits intraperitoneal tumor growth only slightly, while taurolidine causes a significant decrease in tumor cell growth in vitro as well as intraperitoneal tumor growth and trocar metastases in vivo.

Inhibition of peritoneal tumor cell growth and implantation in laparoscopic surgery in a rat model

BACKGROUND

The pathogenesis of portsite recurrences after laparoscopic surgery is still unknown, and a generally accepted approach to prevent tumor implantation does not exist.

METHODS

The effect of taurolidine and heparin on growth of colon adenocarcinoma DHD/K12/TRb was measured in vitro and in vivo. After incubation of the cells with heparin or taurolidine or both substances, cell kinetics were determined. In a rat model (n = 60), tumor cells were administered intraperitoneally, and pneumoperitoneum was established over 30 minutes. Rats received tumor cells, tumor cells + heparin, tumor cells + taurolidine, or tumor cells + taurolidine + heparin.

RESULTS

In vitro, tumor cell growth decreased after incubation with taurolidine and taurolidine/heparin. In vivo, intraperitoneal tumor weight was lower in rats receiving heparin (298 +/- 155 mg) and taurolidine (149 +/- 247 mg) compared with the control group (596 +/- 278 mg) but even less when both substances were combined (21.5 +/- 36 mg).

CONCLUSION

Heparin inhibits intraperitoneal tumor growth in vivo slightly, while taurolidine causes significant decrease of tumor cell growth in vitro as well as tumor take and intraperitoneal tumor growth in vivo.

The influence of laparotomy and laparoscopy on tumor growth in a rat model

BACKGROUND

The effects of laparotomy and laparoscopy with different gases on subcutaneous and intraperitoneal tumor growth have not been evaluated yet.

METHODS

Tumor growth of colon adenocarcinoma DHD/K12/TRb was measured in rats after laparotomy, laparoscopy with CO2 or air, and in control group. Cell kinetics were determined after incubation with carbon dioxide or air in vitro and tumor growth was measured subcutaneously and intraperitoneally after surgery in vivo.

RESULTS

In vitro, tumor cell growth increased significantly after incubation with air and CO2. In vivo, intraperitoneal tumor weight was increased after laparotomy (1,203 +/- 780 mg) and after laparoscopy with air (1,085 +/- 891 mg) and with CO2 (718 +/- 690 mg) compared to control group (521 +/- 221 mg) (p < 0.05). Subcutaneous tumor growth was promoted after laparotomy (71 +/- 35 mg) and even more after laparoscopy with air (82 +/- 45 mg) and CO2 (99 +/- 55 mg) compared to control group (36 +/- 33 mg).

CONCLUSIONS

Insufflation of air and CO2 promote tumor growth in vitro. In vivo, intraperitoneal tumor growth seems to be promoted primarily by intraperitoneal air and subcutaneous tumor growth by CO2.

Does laparoscopy increase bacteremia and endotoxemia in a peritonitis model?

BACKGROUND

Laparoscopy is increasingly used in patients with intraabdominal bacterial infection although pneumoperitoneum may increase bacteremia by elevated intraabdominal pressure.

METHODS

The influence of laparotomy and laparoscopy on bacteremia, endotoxemia, and postoperative abscess formation was investigated in a rat model. Rats received intraperitoneally a standardized fecal inoculum and underwent laparotomy (n = 20), or laparoscopy (n = 20), or no further manipulation in the control group (n = 20).

RESULTS

Bacteremia and endotoxemia were higher after laparotomy and laparoscopy compared to the control group (p = 0.01) 1 h after intervention. One hour after intervention, aerobic and anaerobic bacterial species were detected in the laparotomy group while only anaerobic bacteria were found in the other two groups. Although bacteremia and endotoxemia did not differ among the three groups after 1 week, the mean number of intraperitoneal abscesses was significantly higher (p < 0.05) after laparotomy (n = 10) compared with laparoscopy (n = 6) and control group (n = 5).

CONCLUSION

Laparoscopy does not increase bacteremia and intraperitoneal abscess formation compared to laparotomy in an animal model of peritonitis.