Hepatic cytokine response can be modulated using the Kupffer cell blocker gadolinium chloride in obstructive jaundice

INTRODUCTION

Depletion of Kupffer cells by gadolinium chloride (GdCl(3)) reduces the systemic response during sepsis. The study aim was to investigate the effect of this depletion on hepatic proinflammatory cytokine response to portal endotoxaemia.

METHODS

Sixteen Wistar rats were randomised to receive either saline IV (n = 8) or GdCl(3) (10 mg/kg IV, n = 8) six days after bile duct ligation (BDL). 24 h later the animals were perfused for 2 h, using isolated hepatic perfusion. Aliquots of effluent perfusate were collected at 20-min intervals for cytokine analysis. Sections of liver were sampled and the hepatic Kupffer cell number of each group was measured using ED1 immunohistochemistry.

RESULTS

Pre-treatment with GdCl(3) resulted in significantly reduced serum bilirubin concentrations but significantly elevated serum ALP and AST levels compared to the control group. It was also associated with a significant reduction in Kupffer cell numbers and a corresponding significant reduction in hepatic TNFα and IL-6 production in response to portal endotoxaemia.

CONCLUSIONS

Pre-treatment with GdCl(3) in jaundiced animals reduced Kupffer cell numbers, attenuated liver enzyme abnormalities and reduced TNFα and IL-6 in response to portal endotoxaemia. Hepatic Kupffer cells, therefore, play a significant role in the development of an exaggerated inflammatory response in obstructive jaundice.

Anti-endotoxin Hyperimmune Globulin Attenuates Portal Cytokinaemia, Phagocytic Cell Priming, and Acute Lung Injury after Lower Limb Ischaemia-reperfusion Injury

OBJECTIVES

Acute limb ischaemia is a common and often lethal clinical event. Reperfusion of an ischaemic limb has been shown to induce a remote gut injury associated with transmigration of endotoxin into the portal and systemic circulation, which in turn has been implicated in the conversion of the sterile inflammatory response to a sepsis syndrome, after lower torso ischaemia-reperfusion injury. This study tests the hypothesis that an anti-endotoxin hyperimmune globulin attenuates ischaemia-reperfusion (I/R) associated sepsis syndrome.

DESIGN

Prospective, randomised placebo controlled trial, animal experiment.

MATERIALS AND METHODS

Experimental porcine model, bilateral hind limb I/R injury, randomised to receive anti-endotoxin hyperimmune globulin or placebo.

RESULTS

Bilateral hind limb I/R injury significantly increased intestinal mucosal acidosis, portal endotoxaemia, plasma cytokine (TNF-alpha, IL-6, IL-8) concentrations, circulating phagocytic cell priming and pulmonary leukosequestration, oedema, and capillary-alveolar protein leak. Conversely, pigs treated with anti-endotoxin hyperimmune globulin (IgG) 20mg/kg at onset of reperfusion had significantly reduced portal endotoxaemia, early circulating phagocytic cell priming, plasma cytokinaemia and attenuation of acute lung injury.

CONCLUSIONS

Endotoxin translocation across a hyperpermeable gut barrier, phagocytic cell priming and cytokinaemia are key events of limb I/R injury induced systemic inflammation and acute lung injury. This study shows that an anti-endotoxin hyperimmune globulin attenuates portal endotoxaemia, which may reduce early phagocytic cell activation, cytokinaemia and ultimately acute lung injury.

The probiotic bacterium Lactobacillus plantarum species 299 reduces intestinal permeability in experimental biliary obstruction

AIMS

Extrahepatic biliary obstruction is associated with the failure of intestinal barrier function, allowing bacteria and other substances from the intestine to enter the circulation and initiate a systemic inflammatory response, causing impairment of organ function. Probiotic bacteria have been shown to have beneficial effects on intestinal barrier function in other conditions, but their effects have never been studied in biliary obstruction.

METHODS AND RESULTS

This study examined the effects of enteral administration of Lactobacillus plantarum species 299 (LP299) in oatmeal fibre compared with sterile oatmeal fibre in water or water alone in an animal model of biliary obstruction. Administration of LP299 was associated with reduced intestinal permeability compared with sterile oatmeal alone (0.262 +/- 0.105%vs 0.537 +/- 0.037%, P=0.019, percentage excretion of (14)Carbon), but there was no evidence of reduced endotoxin exposure or blunting of the systemic inflammatory response. Animals receiving sterile oatmeal fibre alone also failed to develop the hyperpermeability after biliary obstruction seen in animals receiving water only (0.512+/- 0.05%vs 0.788 +/- 0.18%), suggesting that oatmeal itself may have some beneficial effects on intestinal barrier function.

CONCLUSION

Enteral administration of the probiotic bacterium LP299 reduces intestinal hyperpermeability associated with experimental biliary obstruction.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides insight to direct further work into the modulation of intestinal barrier function by probiotic bacteria.

Glutamine improves intestinal barrier function in experimental biliary obstruction

OBJECTIVE

To determine the effects of enteral administration of glutamine on intestinal barrier function in experimental biliary obstruction.

BACKGROUND

Extrahepatic biliary obstruction is associated with the failure of intestinal barrier function, allowing bacteria and other substances from the intestine to enter the circulation and initiate a systemic inflammatory response, causing impairment of multiple organs. The amino acid glutamine has been shown to improve intestinal barrier function in other conditions, but its effects in biliary obstruction have not been fully examined.

METHODS

This study examined the effects of enteral administration of glutamine on intestinal permeability and on bacterial translocation from the intestine in a rodent model of biliary obstruction.

RESULTS

Glutamine was shown to reduce intestinal permeability measured as percentage excretion of 14C 7 days after biliary obstruction (0.35+/-0.03 vs. 0.56+/-0.085% in controls, p=0.028), and glutamine administration was also associated with a decreased incidence of bacterial translocation to extra-intestinal sites (p=0.03). Radiolabelled bacterial studies also demonstrated reduced translocation of bacterial fragments to extra-intestinal sites in glutamine-treated animals (p=0.01). There was also some evidence of decreased exposure to endotoxin, reduced systemic inflammation and increased bacterial killing by the immune system in glutamine-treated animals.

CONCLUSIONS

Glutamine modulates intestinal permeability and reduces bacterial translocation in an animal model of experimental biliary obstruction and may increase bacterial killing by the immune system.

Metallothionein crypt-restricted immunopositivity indices (MTCRII) correlate with aberrant crypt foci (ACF) in mouse colon

Metallothionein (MT) crypt-restricted immunopositivity indices (MTCRII) are colonic crypt stem cell mutation markers that may be induced early and in abundance after mutagen treatment. Metallothionein is the endogenous reporter gene for MTCRII, but is not typically implicated in the classical pathway of colorectal tumorigenesis. Hence, the oncological relevance of MTCRII is unclear. This study tests the hypothesis that MTCRII induced by N-methyl-N-nitrosourea (MNU) and lambda carrageenan (lambdaCgN) associate with aberrant crypt foci (ACF) in mouse colon. Undegraded lambdaCgN and MNU were tested alone and in combination against MTCRII and ACF in Balb/c mice, at 20 weeks after the start of treatment. MTCRII were unaffected by lambdaCgN alone. Combined lambdaCgN/MNU treatments induced greater MTCRII (P < 0.01) as well as greater number (P < 0.001) and crypt multiplicity (P < 0.01) of ACF than MNU alone. MTCRII were approximately 10-fold more numerous than ACF, although linear correlations were observed between these parameters (r = 0.732; P < 0.01). MTCRII are induced by lambdaCgN/MNU interactions in sufficient numbers to provide statistical power from relatively small sample sizes and correlate with ACF formation. MTCRII could thus provide the basis for a novel medium-term murine bioassay relevant to early-stage colorectal tumorigenesis.

Patterns of bacterial translocation in experimental biliary obstruction

INTRODUCTION

Biliary obstruction is associated with impaired intestinal barrier function and translocation of enteric bacteria to the systemic circulation. Traditional live culture techniques may overlook translocation of dead bacterial fragments that stimulate the inflammatory response. The aim of this study was to estimate the extent and pattern of bacterial translocation in experimental biliary obstruction.

MATERIALS AND METHODS

Thirty 9-week-old male Wistar rats were randomized to undergo bile duct ligation (BDL, n = 20) or sham operation (n = 10). Seven days after operation, each animal received 1 ml of (111)indium-oxyquinolone-labeled Escherichia coli p.o. Samples of liver, spleen, mesenteric lymph nodes, and lung were harvested 4 h later and analyzed for live bacteria and (111)indium activity.

RESULTS

There was significantly more live bacterial translocation detected in BDL animals than in sham-operated animals (P = 0.00008, chi(2)). Labeled bacterial fragments were detected in all locations sampled in all animals. Sham-operated animals had significantly more labeled bacterial fragments detected in the liver (P = 0.0001) and the spleen (P = 0.03) than the BDL animals. The mean total bacterial survival in the BDL group was 30 +/- 13% and 0% in the sham operated group.

CONCLUSION

These results demonstrate that non-viable bacterial fragments are present in sterile extra-intestinal sites in normal animals and that translocation of live bacteria is markedly increased in experimental biliary obstruction. These results also suggest that failure of bacterial killing is an important factor facilitating bacterial translocation in the presence of established biliary obstruction.

Ischaemic preconditioning before lower limb ischaemia–reperfusion protects against acute lung injury

Background

Ischaemic preconditioning (IPC) of skeletal muscle, by exposing it to repeated brief periods of ischaemia and reperfusion (I-R) before a subsequent longer ischaemic period, protects against local damage on reperfusion. In a large animal model of hindlimb I-R it was hypothesized that hindlimb IPC would attenuate the systemic inflammatory response syndrome and prevent acute lung injury associated with limb reperfusion injury.

Methods

Anaesthetized ventilated swine (six per group) were used throughout. After midline laparotomy, animals were randomized to the following three groups: bilateral external iliac artery occlusion for 120 min, followed by reperfusion for 180 min (I-R group); IPC (three cycles of 5 min ischaemia, then 5 min reperfusion of both external iliac arteries) followed by bilateral external iliac artery occlusion for 120 min and reperfusion for 180 min (I-R + IPC group); or laparotomy alone (control group). Acute lung injury was assessed by invasive pulmonary artery pressure (PAP) measurement, arterial to alveolar (A-a) oxygen gradient, lung tissue wet: dry weight ratio, and lung myeloperoxidase (MPO) concentration.

Results

Conclusion

Lower limb I-R induces systemic inflammation and acutely impairs oxygen transport associated with lung neutrophil sequestration. IPC attenuates acute pulmonary hypertension, impairment of oxygen transport, oedema and leucosequestration in planned lower limb I-R.

Bactericidal/permeability-increasing protein attenuates systemic inflammation and acute lung injury in porcine lower limb ischemia-reperfusion injury

OBJECTIVE

To investigate the role of recombinant bactericidal/permeability-increasing protein (rBPI21) in the attenuation of the sepsis syndrome and acute lung injury associated with lower limb ischemia-reperfusion (I/R) injury.

SUMMARY BACKGROUND DATA

Gut-derived endotoxin has been implicated in the conversion of the sterile inflammatory response to a lethal sepsis syndrome after lower torso I/R injury. rBPI21 is a novel antiendotoxin therapy with proven benefit in sepsis.

METHODS

Anesthetized ventilated swine underwent midline laparotomy and bilateral external iliac artery occlusion for 2 hours followed by 2.5 hours of reperfusion. Two groups (n = 6 per group) were randomized to receive, by intravenous infusion over 30 minutes, at the start of reperfusion, either thaumatin, a control-protein preparation, at 2 mg/kg body weight, or rBPI21 at 2 mg/kg body weight. A control group (n = 6) underwent laparotomy without further treatment and was administered thaumatin at 2 mg/kg body weight after 2 hours of anesthesia. Blood from a carotid artery cannula was taken every half-hour for arterial blood gas analysis. Plasma was separated and stored at -70 degrees C for later determination of plasma tumor necrosis factor (TNF)-alpha, interleukin (IL)-6 by bioassay, and IL-8 by enzyme-linked immunosorbent assay (ELISA), as a markers of systemic inflammation. Plasma endotoxin concentration was measured using ELISA. Lung tissue wet-to-dry weight ratio and myeloperoxidase concentration were used as markers of edema and neutrophil sequestration, respectively. Bronchoalveolar lavage protein concentration was measured by the bicinclinoic acid method as a measure of capillary-alveolar protein leak. The alveolar-arterial gradient was measured; a large gradient indicated impaired oxygen transport and hence lung injury.

RESULTS

Bilateral hind limb I/R injury increased significantly intestinal mucosal acidosis, intestinal permeability, portal endotoxemia, plasma IL-6 concentrations, circulating phagocytic cell priming and pulmonary leukosequestration, edema, capillary-alveolar protein leak, and impaired gas exchange. Conversely, pigs treated with rBPI21 2 mg/kg at the onset of reperfusion had significantly reduced intestinal mucosal acidosis, portal endotoxin concentrations, and circulating phagocytic cell priming and had significantly less pulmonary edema, leukosequestration, and respiratory failure.

CONCLUSIONS

Endotoxin transmigration across a hyperpermeable gut barrier, phagocytic cell priming, and cytokinemia are key events of I/R injury, sepsis, and pulmonary dysfunction. This study shows that rBPI21 ameliorates these adverse effects and may provide a novel therapeutic approach for prevention of I/R-associated sepsis syndrome.

Gut mucosal injury is attenuated by recombinant bactericidal/permeability-increasing protein in hind limb ischemia-reperfusion injury

Lower limb ischemia-reperfusion injury (IRI) is associated with increased gut permeability to endotoxin, which not only directly damages enterocytes but also stimulates a systemic inflammatory response syndrome (SIRS), compounding gut injury. Recombinant bactericidal/permeability-increasing protein (rBPI21) is a novel anti-endotoxin therapy with proven benefit in sepsis. Its potential role in modulating remote gut injury in hind limb IRI was studied. Male Wistar rats were chosen for a prospective randomized control trial (n = 10 per group). The control group and two groups undergoing 3 hr bilateral hind limb ischemia with 2 hr reperfusion (I/R) were randomized to receive intravenously either control protein thaumatin at 2 mg/kg or rBPI21 at 2 mg/kg, respectively. Quantitative morphometric assessment of the small bowel was used as a measure of gut injury and, using an ex vivo everted gut sac model, translocation of 14C-labeled polyethylene glycol (PEG) was used as a measure of gut permeability. Our results indicate that hind limb IRI is associated with remote gut mucosal injury and increased permeability to macromolecules. rBPI21 anti-endotoxin therapy modulates remote gut injury associated with lower limb IRI in this model.

Recombinant bactericidal/permeability-increasing protein attenuates the systemic inflammatory response syndrome in lower limb ischemia-reperfusion injury

OBJECTIVES

Hind limb ischemia-reperfusion (I/R) injury increases gut permeability, and resultant endotoxemia is associated with an amplified systemic inflammatory response syndrome leading to multiple organ dysfunction syndrome. We studied the potential role of recombinant bactericidal/permeability-increasing protein (rBPI(21) ), a novel antiendotoxin therapy, in modulating endotoxin-enhanced systemic inflammatory response syndrome in hind limb I/R injury.

METHODS

In this prospective, randomized, controlled, experimental animal study, 48 male Wistar rats, weighing 300 to 350 g, were randomized to a control group (sham) and five groups undergoing 3 hours bilateral hind limb ischemia with 2 hours reperfusion (I/R) (n = 8 per group). The control and untreated I/R groups received thaumatin, a control-protein preparation, at 2 mg/kg. Treatment groups were administered rBPI(21) intravenously at 1, 2, or 4 mg/kg body weight at the beginning of reperfusion; an additional group was administered rBPI(21) intravenously at 2 mg/kg after 1 hour of reperfusion. Plasma interleukin-6 concentration was estimated by bioassay as a measure of systemic inflammation. Plasma endotoxin concentration was determined by use of an amebocyte lysate chromogenic assay. Crossreactive immunoglobulin G and M antibodies to the highly conserved inner core region of endotoxin were measured by use of an enzyme-linked immunosorbent assay. The lung tissue wet-to-dry weight ratio and myeloperoxidase concentration were used as markers of edema and neutrophil sequestration, respectively.

RESULTS

I/R provoked highly significant elevation in plasma interleukin-6 concentrations (1351.20 pg/mL [860.16 - 1886.40 pg/mL]) compared with controls (125.32 pg/mL [87.76-157.52 pg/mL; P <.0001]), but treatment with rBPI(21) 2 mg/kg at onset of reperfusion (715.89 pg/mL [573.36-847.76 pg/mL]) significantly decreased interleukin-6 response compared with the nontreatment group ( P <.016). I/R increased plasma endotoxin concentrations significantly (21.52 pg/mL [6.20-48.23 pg/mL]), compared with control animals (0.90 pg/mL [0.00-2.30 pg/mL; P <.0001]), and treatment with rBPI(21) 4 mg/kg at reperfusion significantly decreased endotoxemia (1.30 pg/mL [1.20-2.20 pg/mL]), compared with the untreated group ( P <.001). The lung tissue myeloperoxidase level was significantly increased in the untreated I/R group (208.18% [128.79%-221.81%]), compared with in controls (62.00% [40.45%-80.92%; P <.0001]), and attenuated in those treated with rBPI(21) 2 mg/kg (129.54% [90.49%-145.78%; P <.05]). Data represent median and interquartile range, comparisons made with the nonparametric Mann-Whitney U test.

CONCLUSIONS

These findings show that hind limb ischemia-reperfusion injury is associated with endotoxemia, elevations in plasma interleukin-6, and pulmonary leukosequestration. Treatment with rBPI(21) after ischemia reduces endotoxemia, the interleukin-6 response, and attenuates pulmonary leukosequestration in response to hind limb reperfusion injury.

Circulating neutrophil priming and systemic inflammation in limb ischaemia-reperfusion injury

BACKGROUND

Recruitment and activation of neutrophils is a key step in the development of local and systemic injury in lower limb ischaemia-reperfusion. We hypothesis that increased circulating neutrophil priming is responsible for systemic inflammation.

METHODS

Anaesthetised ventilated swine (n = 6 per group) underwent mid-line laparotomy and were randomised to control group or bilateral external iliac artery occlusion for two hours followed by two and a half hours reperfusion (I/R group). Using luminol, respiratory burst activity was assayed with a BioOrbit Luminometer to detect whole blood chemiluminescence (CL) by stimulation with phorbol 1,2-myristate 1,3-acetate (PMA) in the absence or presence of tumour necrosis factor (TNF) respectively. PMN priming is expressed as the ratio of whole blood CL in the presence of TNF to that without. We measured plasma interleukin(IL)-6 and tumour necrosis factor alpha by bioassay as a measure of systemic inflammation. The alveolar-arterial (A-a) gradient was measured using the formula [(A-a)gradient = fraction inspired O2 x 710-(arterial pCO2/0.8)-arterial pO2], it is a measure of lung function, a large gradient being indicative of impaired oxygen transport and hence lung injury.

RESULTS

Lower limb I/R caused significantly greater PMN priming, 0.83 +/- 0.14, compared to control group, 0.22 +/- 0.04, (p < 0.001). Plasma IL-6, a reliable indicator of systemic inflammation, was significantly increased in I/R group after two and a half hours of reperfusion, 1295.0 (833.9-2073.0) pg/L, compared to control, 382.9 (367.4-568.3) pg/L, (p < 0.005). Plasma tumour necrosis factor alpha was significantly elevated after one hour of reperfusion in the I/R group, 86.8 (48.7-106.6) pg/ml, compared to the control group, 32.7 (0.9-42.8) pg/ml, (p < 0.01). (A-a) gradient was significantly increased after IRI, 407.97 +/- 53.13, compared to the control, 183.19 +/- 45.75, (p < 0.005). Mean pulmonary artery pressure was significantly greater after IRI, 38.80 +/- 4.87 mmHg, compared to control, 27.86 +/- 1.92 mmHg, (p < 0.005). Data represents mean +/- standard error mean or median (interquartile range), statistical comparisons using one-way Anova with Student's "t"-test and Kruskall-Wallis Anova with the Mann-Whitney U test.

CONCLUSIONS

Priming of neutrophils increases their circulating respiratory burst activity and ability to induce tissue injury. Systemic PMN priming during hind limb ischaemia-reperfusion injury is associated with the systemic inflammatory response syndrome.

Probiotic therapy fails to improve gut permeability in a hapten model of colitis

BACKGROUND

Studies in clinical and experimental inflammatory bowel disease (IBD) have shown disturbances in intestinal bacterial flora with an increase in potentially pathogenic and a decrease in protective organisms. It was hypothesized that Lactobacillus plantarum species 299 (LP299), a probiotic, would ameliorate colitis and improve intestinal permeability in experimental colitis. This study investigated the effect of LP299 in the trinitrobenzenesulfonic acid/ethanol (TNBS/E) rat model of colitis.

METHODS

Twelve week old male Wistar rats were randomized to receive rectal instillates of either TNBS/E (n = 48) or saline (n = 16). For the next 7 days the animals were gavaged with 2.5 ml of oat fibre suspension containing 10(9) colony forming units (CFU) of LP299 (LP299/OF), oat fibre suspension alone (OF) or no treatment. At the end of the experiment rats received radiolabelled polyethylene glycol and urine was collected for 24 h to assess permeability. Animals were then anaesthetized and colons were harvested for colon macroscopic scoring (CMS).

RESULTS

TNBS/E per rectum resulted in a greater CMS (P < 0.001) and gut permeability (P = 0.006) than saline. Administration of LP299/OF or oat fibre alone did not result in a reduction in CMS or gut permeability when compared to colitic controls.

CONCLUSIONS

LP299/OF, when administered after TNBS instillation, does not reduce the severity of colitis or improve gut permeability in this hapten model of colitis.

Interleukin 10-deficient colitis: new similarities to human inflammatory bowel disease

BACKGROUND

Interleukin (IL) 10 is a potent anti-inflammatory cytokine. Disruption of the IL-10 gene in C57/Black6 mice results in enterocolitis in the presence of intestinal bacteria. This study investigated gut mucosal barrier function sequentially during the development of colitis in this model.

METHODS

Animals were bred in specific pathogen-free conditions and transferred to conventional housing at 4 weeks. Mice were evaluated at 6, 8, 10, 12, 14 and 15 weeks of age. Barrier function was assessed by measuring intestinal permeability and antibody response to systemic endotoxaemia (antibody to the core glycolipid region of lipopolysaccharide; EndoCAb). Colons were harvested and a histological injury score (HIS) was calculated.

RESULTS

The HIS increased progressively until 12 weeks, with an associated increase in intestinal permeability, and immunoglobulin (Ig) M and IgG EndoCAb. The HIS correlated positively with both intestinal permeability and IgM and IgG EndoCAb. Intestinal permeability showed a positive correlation with EndoCAb.

CONCLUSION

IL-10 knockout mice develop colitis with an associated disturbance in gut mucosal barrier function, as measured by increased permeability and endotoxaemia. The colitis found in the IL-10 knockout mouse shares these histological, physiological and biochemical features with human inflammatory bowel disease and is therefore suitable for therapeutic trials. A measure of endotoxaemia correlated directly with intestinal permeability in this model.

Cytokine profile in chronic cardiac failure

Elevated tumour necrosis factor alpha (TNF-alpha) has been demonstrated in chronic cardiac failure (CCF) and may relate to severity of CCF and development of cachexia. We measured TNF receptor p55 in addition to TNF-alpha in an attempt to improve the detection rate of TNF-alpha activation, and simultaneously measured interleukin 6 (IL-6), interleukin 8 (IL-8) and C-reactive protein. Thirty-four patients with CCF and 24 control subjects were studied. Only TNF receptor p55 [6.95 (0.77-42.3) vs. 5.52 (1.50-13.36) ng mL-1 (median (range)] and IL-6 [0.335 (0-9.79) vs. 0(0-14.71) pg mL-1) were significantly elevated in patients compared with control subjects (both P < 0.05). All inflammatory markers were more frequently elevated in patients, but none correlated with any of the clinical parameters studied. Reasons for inflammatory marker elevation in CCF are uncertain, but future studies should measure the p55 TNF receptor and IL-6 in addition to TNF-alpha, to improve detection of cytokine activity.

Effect of supplemental L-arginine in a chemical-induced model of colorectal cancer

L-Arginine inhibits the development of spontaneous, transplantable solid tumors and chemically induced mammary tumors. The aim of the present study was to investigate the effect of l-arginine on chemically induced colorectal cancer in male Wistar rats. Colorectal cancer was induced in all animals by weekly subcutaneous injections of the colonic procarcinogen 1,2-dimethylhydrazine (DMH) at a dosage of 20 mg/kg body weight. Arginine was given in a 1% solution of drinking water. Group I was the DMH control; group II, arginine for 22 weeks; group III, arginine for the first 10 weeks only. Lymphocyte function was evaluated by measuring the thymic lymphocyte proliferative response to the T cell mitogen phytohemagglutinin. The results show that tumor incidence and tumor burden (tumors/rat and tumors/tumor-bearing rat) were significantly reduced in both groups of animals receiving arginine compared to DMH controls (p < 0.05). The tumor areas and volumes were also reduced in both arginine groups (p < 0.05). Thymic lymphocyte stimulation indices were significantly increased by arginine supplementation (p < 0.05). These results would be in keeping with the reduction in colorectal tumor production due to a "nonspecific" stimulation of the host immune system by L-arginine.

Can thymidine kinase levels in breast tumors predict disease recurrence?

BACKGROUND

Our previous study of thymidine kinase (TK) levels in the serum of breast cancer patients demonstrated a statistically significant positive correlation with cancer stage. In postsurgical follow-up studies of 20 patients with primary breast cancer, total serum TK levels rose with disease recurrence and continued to rise with disease progression but decreased with treatment response.

PURPOSE

This study was designed to examine whether TK levels in primary breast tumors can be used to predict recurrence and to establish the relationship between TK levels and estrogen receptor (ER) status and recurrence.

METHODS

Eighty-six patients with breast cancer were entered in this study. Tumors were assessed for ER status and TK levels, and the patients had follow-up for recurrence over a period of 41 months. By calculating the percent of TK activity in the presence of adenosine triphosphate (ATP) or cytidine triphosphate (CTP), we estimated the relative contributions of TK isozymes TK1 and TK2 to total TK activity.

RESULTS

Total TK (TK1 plus TK2) levels in tumors were significantly (P < .001) elevated in patients who subsequently had recurrence compared with levels in those who did not. Calculations of the percent of TK activity in the presence of ATP or CTP showed that this elevation was due to increased TK1 isozyme levels. ER-negative (ER-) patients had significantly (P < .001) increased TK1 levels relative to those in ER-positive (ER+) patients. ER- patients with recurrence had significantly (P < .001) elevated total tumor TK levels compared with levels in those who did not have recurrence, and calculation of percent of TK activity with ATP or CTP indicated elevated TK1 levels. A similar pattern of increased levels of total tumor TK and TK1 was observed in ER+ patients with recurrence.

CONCLUSIONS

The results indicate that total tumor TK levels were significantly higher in breast cancer patients who subsequently had recurrence than levels in those who did not. This finding appears to be largely caused by higher levels of TK1.

IMPLICATIONS

Higher TK1 levels in tumors in patients who subsequently had disease recurrence almost certainly indicate a high rate of proliferation in such tumors at the time of excision. It appears that TK is a potentially useful marker in the management of breast cancer. With measurement of levels of TK, particularly TK1, in breast tumors and serum, it may be possible to predict recurrence of breast cancer.

Breast tumour thymidine kinase levels and disease recurrence

Thymidine kinase (TK) exists in two forms, TK1 and TK2. TK levels and oestrogen receptor status (OR) were measured in tumours from 86 patients with operable breast cancer and the patients were monitored for recurrence over 24 months. During the monitored period, 13 patients showed recurrence. These patients also exhibited higher total TK levels per mg tumour (P < 0.01) and higher TK1 levels (P < 0.001) than those who did not show recurrence. TK1 levels relative to TK2 were significantly higher (P < 0.05) in OR-negative tumours (n = 29) than in OR-positive tumours (n = 57). OR-negative (n = 9) and OR-positive (n = 4) patients who recurred had significantly higher TK1 levels relative to TK2 than did those who not recur (n = 20 and n = 53, respectively). These preliminary results indicate that breast tumour TK levels may have value in determining prognosis.

The prognostic significance of marrow micrometastases in women with early breast cancer

Twenty-five patients with early breast cancer (T0-T2, N0-N1, M0) have been studied prospectively to determine the relationship between marrow micrometastases, disease-free interval and survival. Marrow specimens were aspirated from three sites immediately prior to breast surgery. An immunocytochemical technique using monoclonal antibody LICR.LON.M8.4 was employed to detect micrometastases. The minimum follow-up was 38 months. Twelve of the 25 patients (48%) had micrometastatic lesions in their marrow at presentation. Four of these patients developed distal recurrence during follow-up, causing death in two of them. Five of the 13 patients with no evidence of micrometastases developed distant recurrence and four of them have died. There was no correlation between the state of the marrow and the development of metastatic disease, although axillary lymph node status, disease stage and tumour volume correlated significantly with outcome (all P less than 0.025). Micrometastatic lesions appear to be common in the marrow of patients with early breast cancer. We have been unable to demonstrate that they have prognostic significance.

Development and reversibility of T lymphocyte dysfunction in experimental obstructive jaundice

This study evaluates the effect of experimental biliary obstruction by bile duct ligation (BDL) and biliary drainage on cell-mediated immunity in Wistar rats. Immune status has been assessed by a mitogen stimulation test of T lymphocytes with phytohaemagglutinin. Animals were followed for up to 35 days after BDL. Regression analysis showed a significant negative correlation between lymphocyte function and the period of jaundice (correlation coefficient -0.57, P less than 0.001). Following BDL for 21 days, groups of animals had internal biliary drainage for 7, 14 and 28 days, and external drainage for 14 days. Compared with obstructed animals, 14 days internal drainage was required to improve lymphocyte function (P less than 0.05). Animals which had 14 days of external drainage had significantly lower lymphocyte stimulation than internal drainage animals (P less than 0.05). The results demonstrate that obstructive jaundice produces a progressive reduction of T lymphocyte function. This can be reversed by biliary drainage, internal drainage being more effective than external drainage.

Assessment of ornithine decarboxylase activity in rectal mucosa as a marker for colorectal adenomas and carcinomas

We have investigated the role of ornithine decarboxylase activity in rectal mucosa as a marker for colorectal neoplasia. Biopsies of normal rectal mucosa were taken from 18 patients with adenomas greater than 1 cm diameter, 11 with carcinomas and 16 controls. The mean ornithine decarboxylase activity in normal rectal mucosa of adenoma patients, 6.52 nmol CO2 released h-1 (mg cell protein)-1, was significantly lower than that in controls, 16.8, P = 0.006. The difference in rectal ornithine decarboxylase activities between cancer patients, 3.58, and controls was also significant, P = 0.001. These preliminary results suggest that ornithine decarboxylase may be a useful marker in screening for colorectal neoplasia.