Thijs Hendriks

Cytokine patterns in patients after major vascular surgery, hemorrhagic shock, and severe blunt trauma. Relation with subsequent adult respiratory distress syndrome and multiple organ failure.

ObjectiveThis study investigates the course of serum cytokine levels in patients with multiple trauma, patients with a ruptured abdominal aortic aneurysm (AAA), and patients undergoing elective AAA repair and the relationship of these cytokines to the development of adult respiratory distress syndrome (ARDS) and multiple organ failure (MOF). Summary Background DataSevere tissue trauma, hemorrhagic shock, and ischemia-reperfusion injury are pathophysiologic mechanisms that may result in an excessive uncontrolled activation of inflammatory cells and mediators. This inflammatory response is thought to play a key role in the development of (remote) cell and organ dysfunction, which is the basis of ARDS and MOF. MethodsThe study concerns 28 patients with multiple trauma, 20 patients admitted in shock because of a ruptured AAA, and 18 patients undergoing elective AAA repair. Arterial blood was serially sampled from admission (or at the start of elective operation) to day 13 in the intensive care unit, and the serum concentrations of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 were determined. ResultsTwenty-two patients died, 15 within 48 hours and 7 after several weeks, as a result of ARDS/MOF. At hospital admission and after 6 hours, these nonsurvivors had significantly higher plasma TNF-α and IL-1β levels than did the survivors. At the same measuring points, TNF-α and IL-1β were significantly more elevated in patients with ruptured AAA than in traumatized patients. However, IL-6 was significantly higher in the traumatized patients. In 10 patients, ARDS/MOF developed, and 41 had an uncomplicated course in this respect. Those with ARDS/MOF exhibited significantly different cytokine patterns in the early postinjury phase. TNF-α and IL-1β levels were higher mainly on the first day of admission; IL-6 concentrations were significantly elevated in patients with ARDS/MOF from the second day onward. The latter cytokine showed a good correlation with the daily MOF score during the whole 2-week observation paeriod. ConclusionsIn the early postinjury phase, higher concentrations of these cytokines are associated; not only with an increased mortality rate, but also with an increased risk for subsequent ARDS and MOF. These data therefore support the concept that these syndromes are caused by an overwhelming autodestructive inflammatory response.

Healing of experimental intestinal anastomoses

Anastomotic dehiscence remains a major complication in surgery of the large bowel, and studies on the healing sequence of experimental anastomoses are necessary to define underlying mechanisms and find ways to improve surgical outcome, particularly in high-risk situations. For the quantitative description of anastomotic repair, both mechanical and biochemical parameters are employed, each with their own limitations. Mechanical parameters, either bursting pressure or breaking strength, only reflect growing anastomotic strength as long as disruption occurs within the anastomotic area, which is less than one week after surgery for the bursting pressure and probably up to two weeks for the breaking strength. The biochemical description of anastomotic repair has been limited to the behavior of collagen, as represented by its rather unique constituent amino acid hydroxyproline. Conclusions based on collagen concentrations—per unit weight—should be considered with caution since they may change as a consequence of changes in noncollagenous substances. In this respect, collagen content, per unit length, is probably a better parameter to describe anastomotic collagen levels. Few investigations have addressed the quality of collagen (e.g.,crosslinking or type). Since, at this time, no distinct correlations have been demonstrated between development of mechanical strength or occurrence of leakage and collagen levels in the healing anastomosis, attention should not be restricted to a description of the quantity of collagen present: the quality of anastomotic collagen should be investigated, perhaps even more so.

Tissue levels of active matrix metalloproteinase-2 and -9 in colorectal cancer.

The bioactivity of matrix metalloproteinases was studied in tissues from colorectal cancer patients by means of both quantitative gelatin zymography and a fluorometric activity assay. Next to paired samples of tumour tissue and distant normal mucosa (n=73), transitional tissue was analysed from a limited (n=33) number of patients. Broad-spectrum matrix metalloproteinase activity and both the active and latent forms of the gelatinases matrix metalloproteinase-2 and -9 were higher in tumour than in normal mucosa. The ratios between active and latent forms of matrix metalloproteinase-2 and -9 were highest in tumour tissue and normal mucosa, respectively. Matrix metalloproteinase-2 levels, both active and latent forms, correlated inversely with stage of disease, the tumours without synchronous distant metastases containing significantly (P=0.005) more active matrix metalloproteinase-2 than the others. At much lower levels of activity, the same trend was observed in distant normal mucosa. The level of latent form of matrix metalloproteinase-9 in tumour depended on tumour location. Neither the active form of matrix metalloproteinase-9 nor broad-spectrum matrix metalloproteinase activity in tumour tissue did correlate with any of the clinicopathological parameters investigated. The results demonstrate explicit differences between the activity of matrix metalloproteinase-2 and -9, indicating different roles for both gelatinases in tumour progression. Such data are necessary in order to develop rational anti-cancer therapies based on inhibition of specific matrix metalloproteinases.

Zymosan-induced generalized inflammation: experimental studies into mechanisms leading to multiple organ dysfunction syndrome.

Patients suffering from multiple organ dysfunction syndrome (MODS) comprise a heterogeneous population, which complicates research in its pathogenesis. Elucidation of the mechanisms involved in the development of MODS will ultimately necessitate the collection of tissue samples and the performance of invasive procedures. These requirements greatly reduce the possibilities for research in human subjects. Therefore, an animal model for MODS is a necessary and valuable tool. In the mid 1980s, the zymosan-induced generalized inflammation (ZIGI) model was introduced. Intraperitoneal injection of zymosan in mice or rats leads, in the course of 1 to 2 weeks, to increasing organ damage and dysfunction. The ZIGI model has been recognized as the one that best resembles human MODS and it has been used widely to study systemic inflammation in relation to organ failure. This review describes the ZIGI model and gives an overview of the results obtained.

Biologic grafts for ventral hernia repair: a systematic review

BACKGROUND Biologic grafts hold promise of a durable repair for ventral hernias with the potential for fewer complications than synthetic mesh. This systematic review was performed to evaluate the effectiveness and safety of biologic grafts for ventral hernia repair. METHODS MEDLINE, Embase, and Cochrane Central Register of Controlled Trials were searched for studies on biologic grafts for the repair of ventral hernias. Outcomes are presented as weighted pooled proportions. RESULTS Twenty-five retrospective studies were included. Recurrence depended on wound class, with an overall rate of 13.8% (95% confidence interval [CI], 7.6-21.3). The recurrence rate in contaminated/dirty repairs was 23.1% (95% CI, 11.3-37.6). Abdominal wall laxity occurred in 10.5% (95% CI, 3.7-20.3) of patients. The surgical morbidity rate was 46.3% (95% CI, 33.3-59.6). Infection occurred in 15.9% (95% CI, 9.8-23.2) of patients but only led to graft removal in 4.9% of cases. CONCLUSIONS No randomized trials are available to properly evaluate biologic grafts for ventral hernia repair. The current evidence suggests that biologic grafts perform similarly to other surgical options. Biologic grafts are associated with a high salvage rate when faced with infection.

Microscopic analysis of anastomotic healing in the intestine of normal and diabetic rats.

PURPOSE: The mechanisms that cause diabetes to impair the development of anastomotic strength in the intestine are poorly understood. We investigated whether short-term uncontrolled diabetes causes alterations in microscopic aspects of anastomoses from the ileum and colon. METHODS: Eighteen Wistar rats were rendered diabetic one week before operation by intravenous streptozotocin injection (50 mg/kg), resulting in nonfasting blood glucose levels of approximately 20 mmol/l. Another 18 age-matched rats were used as controls with a normal blood glucose range of 5 to 7 mmol/l. All rats underwent resection and anastomosis of both the ileum and colon. Animals were killed at one, three, or seven days after operation. Cellular and architectural parameters of anastomotic healing were scored in hematoxylin and eosin-stained sections. Anastomotic collagen content was analyzed by image analysis in picrosirius red-stained sections. RESULTS: Anastomotic necrosis, edema, and epithelial recovery were not affected by diabetes. In diabetic rats, the number of polymorphonuclear cells and macrophages was significantly (P=0.025 and 0.0002, respectively) increased in ileal anastomoses one and three days after operation. In colonic anastomoses, the number of polymorphonuclear cells was increased at one (P=0.001) and seven (P=0.014) days after operation. Repair of the submucosal-muscular layer in colonic anastomoses from diabetic rats was impaired seven days after surgery (P=0.0071), but in ileal anastomoses no difference was found. In the anastomotic area, collagen deposition at postoperative Days 1, 3, and 7 remained unaffected by diabetes. CONCLUSION: Experimental diabetes leads to alterations in cellular components involved in the early phase of repair of intestinal anastomoses but not to a reduced accumulation of wound collagen.

Matrix metalloproteinase 2 and 9 activity in patients with colorectal cancer liver metastasis.

Matrix metalloproteinases (MMPs) have been reported to play an important role in tumour cell invasion and metastasis. The bioactivity of MMPs in liver metastasis from colorectal cancer was investigated and correlated with clinicopathological variables.

Wound healing in the intestinal wall

The healing of both rabbit ileal and colonic infected anastomoses has been investigated. Infection was induced by implanting a capsule with human fecal material in the anastomotic area. Infection did result in lowered bursting pressures, which effect was most pronounced in ileum seven days postoperatively. In general, the average hydroxyproline levels in and around infected anastomoses were lower than the hydroxyproline concentrations measured around noninfected anastomoses. This difference was most significant in the segment proximal to the ileal anastomosis seven days after operation, in the segment distal to the colonic anastomosis three days after operation, and in the segment proximal to the colonic anastomosis seven days after operation. It is concluded that infection interferes with the early stages of the healing sequence in rabbit intestinal anastomoses, profoundly affecting collagen metabolism. Our work does not support recent publications that report an unchanged or even increased wound strength under infected conditions.

Inflammatory cytokines in an experimental model for the multiple organ dysfunction syndrome

OBJECTIVE To investigate the alterations in circulating pro-inflammatory cytokines and cytokine production by peritoneal macrophages during the development of multiple organ dysfunction syndrome. DESIGN Prospective, controlled laboratory study on zymosan-induced generalized inflammation in mice. Single intraperitoneal administration of zymosan induces, over a 12-day period, a triphasic illness in mice; the third phase, from day 6 onward, resembles multiple organ dysfunction syndrome. SETTING Animal research laboratory. SUBJECTS C57BL/6CRW mice received a single intraperitoneal dose of zymosan on day 0, and standard numbers of animals were killed at different time points up until day 12. MEASUREMENTS AND MAIN RESULTS Plasma concentrations of interleukin (IL)-1 alpha and IL-1 beta, IL-6, and tumor necrosis factor (TNF)-alpha were measured from 3 hrs to 12 days after administration of zymosan. At the same time points, both lipopolysaccharide-stimulated and unstimulated production of these cytokines by peritoneal macrophages were measured in vitro. Plasma TNF and IL-6 concentrations transiently increased during the first 24 hrs after administration of zymosan. After 8 days, a prominent peak of biologically inactive TNF was observed. Both unstimulated and lipopolysaccharide-stimulated cytokine production by peritoneal cells showed profound changes during the experimental period. CONCLUSIONS These findings seem to confirm our hypothesis that the macrophages are in a continuously activated state and altered in their function, when the animals develop multiple organ dysfunction syndrome. Further studies are needed to elucidate what happens with these cytokines at the tissue level, to better understand the pathophysiology of multiple organ dysfunction syndrome.

Blood Transfusion Impairs the Healing of Experimental Intestinal Anastomoses

Blood transfusions are reported to impair the cell-mediated immune response. Because both T lymphocyte and macrophage function are important for wound repair, the authors investigated the effect of blood transfusions on anastomotic repair. Lewis rats underwent resection of both ileum and colon, followed by the construction of either an everted or an inverted end-to-end anastomosis. Immediately after operation, they received either 3 mL saline intravenously, or 3 mL heparinized blood from Lewis or Brown Norway donors. The animals were killed 3 or 7 days after operation, and anastomotic strength was assessed by measuring the bursting pressure. Anastomotic abscesses and generalized peritonitis were not found in the control group. Blood transfusions, particularly allogeneic, significantly increased the incidence of these septic complications. Three days after operation, anastomotic strength was significantly reduced in both Lewis and Brown Norway transfused groups. For instance, average bursting pressures (± standard deviation [SD]) of inverted ileal anastomoses were 79 ± 13 mmHg in the control group and 46 ± 14 and 21 ± 12 mmHg in the Lewis and Brown Norway transfused groups, respectively. Seven days after operation, the rupture site was found significantly more often within the anastomotic line in the animals that had received blood transfusions. The authors conclude that blood transfusions impair the healing of experimental intestinal anastomoses and increase susceptibility to intra-abdominal sepsis.