JOURNAL

OF SURGICAL

Total Intravenous IVAN

23, 279-288

RESEARCH

(1977)

Hyperalimentation and Hydroxyurea in Hepatoma-Bearing Rats1

L. CAMERON,

PH.D. AND WAID ROGERS,M.D.,

Chemotherapy PH.D.

Departments of Anatomy and Surgery, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78284 Submitted for publication

Total parenteral feeding or intravenous hyperalimentation (IVH) is attracting considerable attention as a nutritional adjunct during cancer chemotherapy [5, 6, 11, 15171. Often cancer patients are cachectic and suffering from starvation to the point that they are considered as a “poor risk” for receiving cancer chemotherapy [5, 11, 151. Recently, a number of reports suggest that combining IVH with chemotherapy not only improves nutritional status, but also increases the patient’s “tolerance” to chemotherapy [3, 5, 6, 11, 15-171. It has been previously demonstrated in this laboratory [3] that growth of rat hepatomas is stimulated by IVH. Also, Steiger et al. [17] reported an increase in mammary tumor growth in rats undergoing IVH. These studies suggest that this nutritional manipulation might make cell cycle-specific chemotherapeutic drugs more effective. As yet there are no statistically significant data available to support this proposition. Clinical evaluation of combined IVH and chemotherapy on cancer patients has indicated good tumor response, but no evidence of tumor growth enhancement [6]. The present study combines IVH and hydroxyurea (HU) chemotherapy in hepatomabearing rats, allowing reliable measurements of such parameters as: (i) body weight; (ii) tumor regression rate; (iii) food and water balance; (iv) tissue pathology; and (v) survival time. Such information can ’ Supported by a grant from the Public Health Service, National Cancer Institute, CA16831

October 27, 1976

be used to determine and manipulate factors which optimize the advantages of combined IVH and cancer chemotherapy. METHODS AND MATERIALS

The techniques and feeding solutions for total IVH in unrestrained rats have been detailed elsewhere [2, 4, 181. Hydroxyurea (HU) employed as the chemotherapeutic agent was made up fresh for each injection: HU was dissolved in warm lactated Ringer solution (1 g/ml) for intraperitoneal injection at 0.75 mg/g of body weight. Both syringe and solution were maintained at 37°C during the injections to keep the HU from crystallizing out of solution. Sevenweek-old male BUF rats were inoculated with the Morris #7777 hepatoma as previously described [3]. All animals were housed individually in metabolic cages 23 days after tumor inoculation. Thirty-six hepatoma-bearing rats were randomized into three equal experimental groups of 12. These included: (i) HU and IVH, (ii) HU and an oral liquid diet ad libitum, and (iii) no chemotherapy and solid food ad libitum. This latter group of rats served chiefly as a source of normal tissues for histological comparison with the two groups of rats treated with HU. On day 27 after tumor inoculation Groups (i) and (ii) were changed from solid food to liquid food ad iibitum. On day 29 Group (i) was begun on IVH as the only source of nutrition. Daily measurements were made of body weight, fluid intake and output, and the

279 Copyright 0 1977 by Academic Ress. Inc. All rights of reproduct~~~ in any form reserved.

ISSN 0022-4804

280

JOURNAL

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RESEARCH:

length and width of each tumor. The crosssectional area of tumors was calculated using the formula for an ellipse and the tumor weight was estimated as reported earlier [3]. Tumors and normal tissues were removed from rats at the time of death (in the case of HU-treated rats specimens were either taken within 30 min of death or, if more than 30 min intervened, the tissues were not used for histopathology). The tissues were fixed for later histologic preparation with a slight modification (3% instead of 10% paraformaldehyde solution) of the procedure of Winbom and Seelig [ 191. Two of the rats in the solid food group were injected with HU, sacrificed 6 hr later, and their tissues were prepared for histol%Y. Statistical differences between values from the different groups were determined by the Student’s t test. RESULTS Tumor Growth, Survival, and Body Weight

Fluid Balance,

The growth and regression of tumor size in response to HU in rats fed by continuous IVH and in rats fed orally ad libitum is shown in Fig. 1. Both groups of rats were given one injection of 0.75 mg of HU per gram of body weight every 6 hr beginning 31 days after tumor inoculation. This figure shows that HU treatment caused a regression in tumor size in both groups of rats. The figure also illustrates that the largest decrease in tumor size occurred between 24 and 48 hr after the start of HU treatment. Possible differences in tumor regression between the two groups were assessed by comparing the maximum percentage decrease in tumor size occurring during the first 36 hr of HU treatment for each hepatoma. On the average, there was a 17.5 t 2.8% tumor weight regression in the rats given liquid diet ad lib. and a 36.6 _t 6.1% regression in tumor weight in the intravenously fed rats. These values are signifi-

VOL. 23, NO. 4, OCTOBER

1977

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Fro. 1. Mean growth and regression of hepatoma size in IVH (i.v. fed) and liquid diet (oral fed) rats before and after the start of HU treatments. The time at which the IVH was begun is indicated by the word surgery on the figure. The solid line represents the best expohential fit to the data before the start of HU treatment. The standard error of the mean is indicated for each data point.

cantly different (P < 0.02) and indicate that the HU-induced tumor regression was greater in rats undergoing continuous IVH than in those offered a liquid diet ad lib. Comparison of survival time after the beginning of HU treatment shows that the rats given IVH survived an average of 47.0 r 2.87 hr whereas the rats given liquid diet ad lib. survived an average of 57.2 + 2.14 hr. This difference is significant (P = 0.01 and shows that in this model combined HU treatment and IVH significantly shortened survival time in tumor-bearing rats when compared to those on an ab lib. liquid diet. Our results from the fluid balance studies may shed some light on the reason for a difference in survival in these two groups. Figure 2 graphs the mean daily liquid food intake in milliliters before and after the start of HU treatment for hepatomabearing rats given either IVH or liquid diet per OS and ad lib. The figure also graphs the mean daily urine output in milliliters.

CAMERON

AND ROGERS: HYPERALIMENTATION

AND CHEMOTHERAPY

281

Food intake is controlled entirely by the pump infusion rate in the intravenously fed rats and was increased along a gradient during the first 3 days. The other group of rats was allowed free access to the same liquid diet. There were no significant differences in food intake prior to the time Group (if was placed on intravenous infusion; however, a significant difference in food intake was apparent by 24 hr after intravenous infusion started. Clearly the intravenously fed rats have a much higher intake of food than the orally fed rats and this difference is maintained throughout the remainder of the experiment. Mean daily urine output is not significantly different between the groups of rats until 1 day after the start of intravenous infusion. Just as the mean daily food intake increases due to intravenous infusion, the mean urine output also increases until the v 4 start of HU treatment. The start of HU treatment is followed by a marked decrease in urine output in the IVH rats. This decrease in urine output in the IVH rats continues until reaching a level not significantly difIVFED ferent than that of the orally fed rats by 2 days after the start of HU treatment. b ORAL FED To get more complete information on fluid balance differences we calculated the l NS NS

Total intravenous hyperalimentation and hydroxyurea chemotherapy in hepatoma-bearing rats.

JOURNAL OF SURGICAL Total Intravenous IVAN 23, 279-288 RESEARCH (1977) Hyperalimentation and Hydroxyurea in Hepatoma-Bearing Rats1 L. CAMERON,...
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