Dietary supplementation with a specific combination of high protein, leucine, and fish oil improves muscle function and daily activity in tumour-bearing cachectic mice

Abstract

Cancer cachexia is characterised by metabolic alterations leading to loss of adipose tissue and lean body mass and directly compromises physical performance and the quality of life of cancer patients. In a murine cancer cachectic model, the effects of dietary supplementation with a specific combination of high protein, leucine and fish oil on weight loss, muscle function and physical activity were investigated. Male CD2F1 mice, 6-7 weeks old, were divided into body weight-matched groups: (1) control, (2) tumour-bearing, and (3) tumour-bearing receiving experimental diets. Tumours were induced by s.c. inoculation with murine colon adenocarcinoma (C26) cells. Food intake, body mass, tumour size and 24 h-activity were monitored. Then, 20 days after tumour/vehicle inoculation, the animals were killed and muscle function was tested ex vivo. Tumour-bearing mice showed reduced carcass, muscle and fat mass compared with controls. EDL muscle performance and total daily activity were impaired in the tumour-bearing mice. Addition of single nutrients resulted in no or modest effects. However, supplementation of the diet with the all-in combination of high protein, leucine and fish oil significantly reduced loss of carcass, muscle and fat mass (loss in mass 45, 52 and 65% of TB-con, respectively (P<0.02)) and improved muscle performance (loss of max force reduced to 55-64% of TB-con (P<0.05)). Moreover, total daily activity normalised after intervention with the specific nutritional combination (50% of the reduction in activity of TB-con (P<0.05)). In conclusion, a nutritional combination of high protein, leucine and fish oil reduced cachectic symptoms and improved functional performance in cancer cachectic mice. Comparison of the nutritional combination with its individual modules revealed additive effects of the single components provided.

Figure 1

Differences in muscle and fat mass at day 20 after interventions with single or combined nutritional components (Experiment A). (A) muscle Tibialis Anterior mass and (B) Epididymal fat mass. Con=mice receiving control diet A (AIN93), TB-con=tumour-bearing mice receiving control diet A (AIN93), hpr=high protein, leu=leucine, fo=fish oil. Data are means±s.e.m.; ^*significantly different from TB-con (P<0.02) (k=5, α=10%) (For more details about statistics, see the Materials and Methods section).

Figure 2

The effect of the specific nutritional combination on skeletal muscle function: force frequency curve (ex vivo experiment B). CON=mice receiving control diet B, TB-CON=tumour-bearing mice receiving control diet B, TB-SNC=tumour-bearing mice receiving the specific nutritional combination. Data are means±s.e.m.; data were significantly different from TB-CON when P<0.05 (k=2, α=10%). (A) Maximal contraction force (complete curves significantly different from each other P<0.01). (B) Maximal contraction velocity (complete curves significantly different from each other P<0.01). (C) Maximal relaxation velocity (complete curves significantly different from each other P<0.01). (D) CT90: time needed for contraction from 10 to 90% of maximal force (CON significantly different from TB-CON for range 83–176 Hz; TB-SNC significantly different from TB-CON for range 83–100 Hz).

Figure 3

The effect of the specific nutritional combination on skeletal muscle function during exercise (ex vivo experiment B). CON=mice receiving control diet B, TB-CON=tumour-bearing mice receiving control diet B, TB-SNC=tumour-bearing receiving the specific nutritional combination. Data as means±s.e.m.; data were significantly different from TB-CON when P<0.05, k=2, α=10%). (A) Maximal contraction force (both curves are significantly different from TB-CON till repeat 70). (B) Maximal contraction force corrected for muscle mass (CON is significantly different from TB-CON for repeats 30–50; TB-SNC not significant different from TB-CON). (C) Maximal contraction velocity (both curves significantly different from TB-CON till repeat 70). (D) Maximal contraction velocity corrected for muscle mass (CON significantly different from TB-CON for the first 30 repeats (except for repeat 5 (P=0.06)); TB-SNC significantly different from TB-CON for the first 10 repeats).

Figure 4

Daily activity (in vivo experiment B). (A) Total daily activity as % of daily activity on day 2 for all groups. A significant time × group interaction was observed (P<0.01). (B) Total activity in the dark as percentage of daily activity on day 2 for all groups. (C) Total activity in the light as percentage of daily activity on day 2 for all groups. (A–C): ^*P<0.05 vs TB-CON. (D) Actogram, representing percentages of daily activity during the light period from 7–19 h (white shaded areas) and during the dark period from 19–7 h (grey shaded areas) on days 1–19 (vertical) for all groups separately.