Cachectin activity in the serum of cachectic, tumor-bearing rats

Cachectin/tumor necrosis factor has been postulated to be a possible mediator of cancer cachexia. Using a sensitive bioassay, we attempted to detect circulating cachectin activity in the serum of sarcoma-bearing rats and to correlate levels with measurements of cachexia and the extent of disease. In addition, we resected the tumor to determine the time course of reversal of cachexia and the disappearance of cachectin activity in the serum. Circulating cachectin activity was not detectable in the serum of non-tumor-bearing rats or in tumor-bearing rats until 28 days after implantation. With evidence of food intake and body weight decline, cachectin activity became detectable in the serum and levels increased as cachexia and tumor burden increased. Serum cachectin activity levels correlated directly with tumor burden and inversely with food intake and body weight change. After resection of the tumor, food intake and body weight increased and serum cachectin activity became undetectable. Serum triglyceride levels were higher in cachectic tumor-bearing rats than in pair-fed non-tumor-bearing controls, and levels decreased after tumor resection as cachectin activity decreased. The results suggest that cachectin is a humoral mediator of cachexia in this rat-tumor model.     

Attenuated metabolic response to surgery in tumor-bearing rats

BACKGROUND: During cancer, proteins are chronically wasted, including proteins of the gut. Surgical stress acutely increases protein breakdown of the gut. Surgery in cancer patients may thus have a double effect on the gut and lead to exhaustion and functional loss of the gut. METHODS: Female Lewis rats (+/-200 g) were studied bearing a subcutaneous tumor or after sham implantation. Hysterectomy was performed in half of the rats as a standardized operative procedure. Postoperative protein kinetics of the gut were determined using a primed constant infusion of L-[2,6-(3)H]-phenylalanine. Gut function was assessed by testing its permeability for sugar probes lactulose and L-rhamnose. Villus height and crypt depth were measured and polyamine concentrations were measured as markers for mucosal proliferation and differentiation. RESULTS: In control rats, gut protein breakdown increased from 6 +/- 3 to 32 +/- 8 nmol phenylalanine x 100 g body wt x min after hysterectomy. This was accompanied by increased amino acid membrane transport rates and metabolic shunting. In tumor-bearing rats, increased protein breakdown in response to surgery was attenuated (8 +/- 4 vs 17 +/- 4 nmol x 100 g body wt x min). Surgery increased the lactulose/L-rhamnose recovery ratio, indicating increased gut permeability. In the presence of a tumor gut permeability also increased and it increased further after surgery. No changes in villus height or polyamine levels could explain the increased permeability of the gut. CONCLUSION: The study shows that a mild surgical trauma increases protein breakdown of the gut and simultaneously increases gut permeability. In the presence of a tumor the metabolic response to surgery is attenuated. Gut barrier loss was highest in the combined presence of cancer and the surgical insult.     

Detection of serum MMPs in tumor-bearing hamsters

Background/Purpose: Matrix metalloproteinases (MMPs) have been implicated as playing an important role in cancer invasion and metastasis. MMPs have been identified in various malignancies, including pancreatic duct adenocarcinomas. Methods: We investigated the circulating level of MMP-2 and MMP-9 in sera from Syrian golden hamsters into which hamster pancreatic duct adenocarcinoma tissues had been transplanted subcutaneously (HPDt hamsters). Northern blot analysis and gelatin zymographic analysis were performed to detect the expression of MMPs and that of tissue inhibitors of metalloproteinases (TIMPs) in HPDt hamsters. Results: Northern analysis revealed overexpression of MMP-2, MMP-9, and TIMP-2 mRNAs in subcutaneous tumors of HPDt hamsters as compared with normal pancreatic tissue. Sera from HPDt hamsters possessed significantly higher levels of serum MMP-2 and MMP-9 than control sera, as determined by gelatin zymographic analysis, and there was a significant correlation between tumor growth and serum MMP levels. Conclusions: These results indicate that overexpression of MMP mRNAs is involved in the progression of pancreatic duct adenocarcinomas, and that MMP protein expression in hamster sera is associated with the presence of pancreatic duct adenocarcinoma cells. The findings also suggest that serum MMPs could be useful markers for monitoring patients with pancreatic duct adenocarcinomas. Received: February 6, 2002 / Accepted: June 10, 2002 Offprint requests to: K. Iki     

Host and tumor responses to varying rates of nitrogen infusion in the tumor-bearing rat.

The influence of variations in nitrogen content of nutritional substrate available to the tumor-bearing (TB) host on tumor growth and host have not yet been completely defined. One hundred fifty-two growing Fischer 344 rats were either transplanted with a sarcoma (TB) or injected with saline (NTB, day 0), had aseptic placement of superior vena cava catheter (day 14), and were infused with total parenteral nutrition solutions (days 18-28). Isocaloric solutions (approximately 50 kcal/d) contained either 0%, 5%, 16%, 33%, 67%, 100%, 133%, or 167% of normal intake of an adequate amino acid mixture. Final tumor weight in the 5% group (23.4 +/- 3.0 g) was significantly less than tumor weights of all other groups (range: 33.3 +/- 3.3 to 42.6 +/- 11.3) (p less than 0.05). The carcasses of TB animals were slightly smaller than NTB animals but showed no major alterations in protein, fat, or water composition. This study suggests that the tumor can be starved selectively by strictly nutritional means with complex accompanying host carcass and organ changes.     

Elevated energy expenditure in hepatocytes from tumor-bearing rats

Mechanisms for the development of cancer cachexia are not well defined. Oxygen consumption and the capacity of the host liver to metabolize lactate were studied in isolated hepatocytes from sarcoma-bearing rats (TIH) and pair-fed controls (CH). Basal oxygen consumption (without exogenous substrate) is significantly increased by 65% in the TIH as compared to the CH. The addition of a physiologic concentration of lactate stimulated oxygen consumption over the already stimulated basal state by 13% in the TIH compared to 5% in the CH. When the hepatocytes are incubated with 1.5 mM of [U-14C]lactate, glucose production, lactate oxidation, and entry of lactate carbons into nonsecretory protein are significantly increased in the TIH. Associated with this stimulation is a significant decrease in lactate incorporation into glycogen and lipid in the TIH. This study suggests that the tumor-influenced liver utilizes lactate at an increased rate and its intermediary metabolism is directed toward energy utilization rather than energy storage. The enhanced metabolic processes in the tumor-influenced liver are associated with an increased oxygen consumption which may be a contributory factor to the negative energy balance, a characteristic of cancer cachexia.     

单已基甘氨酰二甲苯胺评估肝脏储备功能的实验研究

目的 通过检测大鼠肝损害不同阶段的血清单乙基甘氨酰二甲苯胺(MEGX),血清支链氨基酸/芳香氨基酸(BCAA/AAA)比值,探究能够敏感反映肝脏组织病理变化的肝储备功能指标.方法 将雄性Wistar大鼠40只分为实验组和对照组,实验组大鼠皮下注射60%四氯化碳橄榄油溶液,对照组则注射生理盐水橄榄油混合液,制备不同时期大鼠肝损害模型,分别在肝损害不同阶段检测血清MEGX,血清BCAA/AAA,常规肝功能,病理组织学检查.结果 随着肝细胞损害程度的加重,大鼠血清MEGX浓度逐级隆低,与肝组织病理学变化较相符;BCAA/AAA亦可反映肝损害的程度,但不及MEGX敏感;而常规肝功能试验与肝组织学变化不相符.结论 测定血清MEGX水平比检测血清BCAA/AAA能够更敏感的反映肝组织病理变化,是评估肝储备功能的较好指标.     

Survival time of tumor-bearing rats as related to operative stress and immunopotentiators

To investigate the mechanism of tumor growth enhancement induced by operative stress in rats, laparo-thoracotomy was performed on day 2 after tumor cell inoculation associated with administrations of various kinds of immunopotentiators. OK-432 (Streptococcal preparation), PS-K (extract from mycelium of Coriolus Versicolor), Lentinan (extract from Lentinus Edodus) and C. parvum were administered intravenously or intraperitoneally in the fractionated form prior to or after inoculation. In general, administration of each immunopotentiator, except for Lentinan, resulted in a recovery from the reduction in survival days after laparo-thoracotomy. In particular, OK-432 administration prior to inoculation showed a significant improvement.     

The importance of body language in relation to mental support

Paper presented at the Fourth Congress of the European Burns Association, Barcelona, Spain 1991     

Preoperative insulin reverses cachexia and decreases mortality in tumor-bearing rats

As a model of surgical stress in the cancer-bearing animal, we resected large flank sarcomas from cachectic rats under ether anesthesia and closed wounds primarily. The metabolic cost of tumor resection was measured using a long-term continuous indirect calorimeter. In the immediate postresection period energy balance decreased and host energy expenditure increased significantly (P less than 0.005). In animals with similar tumor weights, mortality following resection was determined by the degree of cachectic depletion. We then considered whether improvement of preoperative host nutritional status with insulin treatment might improve a subsequent surgical outcome. Insulin, when administered exogenously to cachectic tumor-bearing rats, has been shown to stimulate food intake and preserve host weight and does not stimulate tumor growth. When individual rats bearing a cachexia-producing flank sarcoma demonstrated a decline in food intake to less than 75% of predicted (approximately 25 days after tumor implantation), they were randomized to receive either daily injections of NPH insulin (2 units/100 g/day) for 5 days or no treatment for 5 days. Animals then underwent tumor resection and 14-day survival was measured. All resections were performed in an unbiased manner without the surgeon's knowledge of each rat's treatment status. In an experiment using 59 rats, insulin-treated rats had a threefold higher 5-day preoperative food intake and did not lose weight in the preoperative period, while untreated rats lost 17 g (P less than 0.001). Mortality in the insulin-treated group was 10% versus 28% in the untreated group.(ABSTRACT TRUNCATED AT 250 WORDS)     

Metabolic diagnosis in stone formers in relation to body mass index

It is known that several metabolic abnormalities that favor stone formation have a strong dependence on environmental and nutritional factors. The incidence and prevalence of kidney stone is increasing while there has been a parallel growth in the overweight/obesity rate, and epidemiologic studies have shown a significant association between overweight/obesity and increased nephrolithiasis risk. The aim of this study was to assess if metabolic abnormalities observed in stone patients differ in relation to their BMI. We evaluated 817 renal stone formers (459 men and 358 woman) in an outpatient setting. They were all studied with a standard protocol (two 24 h urine collections and serum parameters) and classified according to their BMI in normal, overweight and obese and according to age in <50 or >50 year old. In the whole population we found that 58.7% were either overweight or obese: 39.4% (n = 322) were OW and 19.3% (n = 158) were OB. The proportion of overweight was significantly higher among men than women. In women of all ages regardless of BMI, hypercalciuria was the most prevalent diagnosis. Hyperuricosuria increased its prevalence significantly only in overweight and obese women <50 years of age (p < 0.01). Hypercalciuria was the predominant diagnosis in normal weight men of both age groups. Hyperuricosuria was the most frequent abnormality in overweight and obese men followed by gouty diathesis and both increased their prevalence significantly from normal weight to obesity and in both age groups (p < 0.05 and <0.01). We conclude that the only abnormalities that increased their prevalence significantly with increasing BMI were hyperuricosuria and gouty diathesis, the first one in men of all ages and women under 50 years of age, while the second one only in men.     

Nutritional repletion of malnourished tumor-bearing and nontumor-bearing rats: Effects on body weight,liver, muscle,and tumor

Effects of nutritional repletion were evaluated in malnourished rats with either no tumor (NTB), small tumor burdens (TB), or large tumor burdens (TB). One hundred and four Sprague-Dawley rats were inoculated with Walker-256 carcinosarcoma and were fed regular diet (RD) for 5 days in Study A. At this time, one group was maintained on RD while the remaining rats were fed a high carbohydrate, protein-free diet (PFD). On Day 15, one PFD group was switched to RD; one PFD group continued on PFD. Eighty-nine NTB rats received an identical dietary protocol. Animals were killed on Days 15, 21, and 33. Mean food intake and carcass weight changes were similar in corresponding groups of TB and NTB rats in Study A. After Day 15, mean carcass weight and liver and muscle protein content increased rapidly in PFD → RD TB and NTB rats, becoming similar to the RD group by Day 33. By Day 33, mean tumor weights and mean total tumor protein content in the PFD group were significantly less than the RD or PFD → RD groups. In Study B, tumor-bearing animals were fed regular diet for 20 days after tumor inoculation to produce a larger tumor burden prior to nutritional depletion. Twelve rats were given PFD; six rats continued on the RD. On Day 30, one PFD group (n = 6) was switched to RD while the other PFD group (n = 6) continued on PFD. On Day 36, all rats were sacrificed. Mean carcass weight, liver, and muscle protein levels at sacrifice were significantly less in the PFD → RD group compared with the RD group, but mean serum protein levels were similar in the two groups. Animals co$tinued on PFD lost significant carcass weight, liver, and muscle protein. The presence of a small tumor (5% carcass weight) did not affect protein repletion in host liver or muscle when an adequate diet was provided, although tumor growth was increased. The presence of a larger tumor burden (>25% carcass weight) significantly inhibited host nutritional repletion.     

Role of insulin resistance in decreasing lipoprotein lipase activity in tumor-bearing rats

The role of insulin resistance in the tumor-induced decrease in tissue lipoprotein lipase (LPL) activity was studied in vivo and vitro in methylcholanthrene-induced sarcoma-bearing rats. Intraperitoneal (ip) injection of 2 U of regular insulin resulted in high-adipose LPL activity in control rats (CTR) of 122.0±42.4 U/mg tissue, but it had little effect on tumor-bearing rats (TBR), which showed a value of only 9.6±5.5 U/mg tissue (P=0.002). When adjusted for serum insulin concentrations, adipose LPL activity remained significantly different between the TBR and CTR at 0.19±0.17 and 0.78±0.29 U/mg tissue, respectively (P=0.02). Following the in vitro incubation with either 1.44 g/l glucose of 1×10^–8 U insulin of adipose tissue fragments obtained from the TBR and the CTR, measurable LPL activity was maintained in the tissue from the CTR for 2h but not in that from the TBR. These results suggest that the decreased LPL activities seen in the tumor-bearing state may be mediated by insulin resistance.     

Lipid kinetic alterations in tumor-bearing rats: reversal by tumor excision

Cancer cachexia is frequently accompanied by hyperlipidemia. To identify the mechanisms underlying this alteration in lipid metabolism, free fatty acid (FFA) and very low density lipoprotein-associated triacylglycerol (VLDL-TG) kinetics were determined in tumor-bearing (subcutaneously implanted methylcholanthrene-induced sarcoma) Fischer 344 rats. The animals were studied after chronic vascular catheterization, in an unanesthetized, undisturbed state, after 24 hr of fasting. They were separated into three groups: control (n = 5), tumor-bearing (n = 5, tumor burden = 10% body weight), and 7 days after tumor excision (n = 5). VLDL-TG and FFA kinetics were assessed by a constant infusion of [3H]palmitate-labeled VLDL-TG and [14C]palmitate bound to albumin, respectively. FFA rate of appearance (FFA-Ra) and clearance (FFA-Cl) and VLDL-TG rate of appearance (VLDL-TG-Ra) and clearance (VLDL-TG-Cl) were determined at steady state. We observed that the tumor-bearing rats had significantly increased FFA-Ra and VLDL-TG-Ra, decreased VLDL-CL, and maintained FFA-Cl, when compared to control. These alterations returned to normal levels after tumor excision. The results suggest that the hyperlipidemia observed in tumor-bearing rats is due to elevated lipolysis rate, maintained rate of plasma FFA clearance, increased triacylglycerol production and VLDL secretion by the liver, and decreased VLDL-TG clearance from plasma. These alterations were reversed 7 days following tumor excision.     

Effects of omega-3 fatty acid supplementation on tumor-bearing rats

BACKGROUND: Dietary fish oil (rich in omega-3 fatty acids: eicosapentaenoic acid and docosahexaenoic acid) suppresses synthesis and activity of proinflammatory cytokines that induce anorexia. We hypothesized that dietary fish oil reverses the feeding pattern of tumor anorexia, increasing food intake and retarding tumor growth. STUDY DESIGN: Thirty-two Fischer rats were placed in Automated Eater Meter cages and randomly divided into four groups: tumor bearing (TB) rats eating normal chow diet (TB-Chow); TB rats eating chow diet supplemented with omega-3 fatty acids (TB-omega-3FA); Controls, non-tumor bearing (NTB) rats eating normal chow (NTB-Chow); and NTB rats with omega-3 fatty acid supplementation (NTB-omega-3FA). Doses of 10(6) methylcholanthrene (MCA) sarcoma cells were subcutaneously injected in TB rats. Daily food intake, meal size (MZ), meal number (MN), body weight, and tumor volume were measured, and rats were euthanized at onset of anorexia. Data were statistically analyzed using analyses of variance (ANOVA) and t-tests. Data are reported as mean +/- SE. RESULTS: Tumor appeared significantly earlier in TB-Chow than in TB-omega-3FA rats (7.5 +/- 0.3 days versus 11.6 +/- 0.8 days, p < 0.05). Daily food intake declined significantly in TB-Chow versus TB-omega-3FA rats 18 days after tumor inoculation and, at onset of anorexia, was 9.41 +/- 1.77 g/day versus 13.32 +/- 0.81 g/day, p < 0.05. Food intake decreased initially by decrease in meal number (at day 15) followed by a decrease in meal size (at day 18). At onset of anorexia, meal size and meal number were significantly decreased in TB-Chow versus TB-omega-3FA rats (0.75 +/- 0.067 g/meal versus 1.05 +/- 0.08 g/meal, p < 0.05) and (9.5 +/- 1.32 versus 12.79 +/- 0.93 meals/day, p < 0.05), respectively. Tumor volume was significantly smaller in TB-omega-3FA versus TB-Chow rats (7.6 +/- 0.6 cm(3) versus 16.5 +/- 1.0 cm(3), p < 0.05), as was tumor weight (7.5 +/- 2.2 g versus 18.1 +/- 1.6 g, p < 0.05). CONCLUSIONS: In TB rats, omega-3FA improved food intake; restored normal eating pattern, delayed onset of anorexia, tumor appearance, and growth; and prevented body weight loss. Supplementation of omega-3 fatty acids has therapeutic potential in cancer anorexia.     

Changes in total body surface area and the distribution of skin surfaces in relation to body mass index

BackgroundA correct estimation of total burn surface area is important since it is used for determining fluid resuscitation volumes, nutritional estimates and hospital admission criteria. Wallace’s rule of nines is the most commonly used methods for this purpose. However, fat distribution is non-uniform and the total body surface area changes with obesity. The aim of this study was to determine if the rule of nines applies to all body mass index groups.MethodsA total of 217 individuals were included in the study. The patients were divided into 4 groups according to their BMI (18.5–25 kg/m² (60 persons)), 25–29.9 kg/m² (61 individuals)), 30–34.9 kg/m² (55 persons)), >35 kg/m² (41 persons)). Each patient underwent a complete duel-energy X-ray absorptiometry body scan to determine the surface area (cm²) of the various regions of the body.ResultsWe found no statistically significant variations between the Wallace body percentage distributions and our results in the men for all BMI ranges (head p = 0.331, arms p = 0.861, legs p = 0.282, trunk p = 0.696). In contrast, among women we found a statistically significant change in body surface area percentage distribution between the BMI groups and specific body regions (head p = 0.000, legs p = 0.000 and trunk p = 0.001).ConclusionThe Wallace rule of nines is a quick and acceptable method for estimating the total burn surface area percentage in men of all BMI ranges. However, for women, a more accurate method of burn area estimation is required as proposed by our BMI adjusted charts.