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Nutrient induced thermogenesis (NIT) during the course of polytraumatized patients
0.23
NUTRIENT 1NDUCED THERMOGENESIS IN CELL CULTURES. L. TeJmar-Kolar, J. Nittinger, P. Ftirst, (Inst. Biol. Chem. & N&r., Univ. of Hohenheim, Stuttgart, FRG)
S. Engel,
Microcalorimetry is a new approach to characterize the metabolic activity by direct, continuous and sensitive measurement of the heat production (HP) in cultured cells. The present study was directed to examine the effect of certain energy substrates on nutrient induced thermogenesis in relation to cellular growth and the glycolytic pathway. Microcalorimetry was performed by using an LKB Therm0 Activity Monitor. Peltier elements are sandwiched between the measuring vessel (containing the sample) and tempered heat sinks create a detectable voltage proportional to the temperature difference which is monitored. Previous studies in MOLT 4 suspension culture revealed a high sensitivity of -0.1 uW (lo-'Co) at -10' cell, the reproducibility being 11.6%. In the present study HP was measured over 72 hours in monolayer anaerobic culture of human embryonal lung fibroblasts (IMR-90) cultured in Dulbecco's MEM normally containing suitable amounts of glucose (Gl, lg/l) and glutamine (Gln, 0.58 g/l). In certain experiments Gl was replaced with fructose (Fr) and sorbitol (So) and Gln was alternatively omitted from the medium. The normal course of cellular HP in presence of Gl and Gln at expected cellular growth results in an increase of HP/culture from 6 uW to 9 uW over 72 h, while the HP/cell decreases from 20 pW to 10 pW. Replacement of Gl with Fr or So failed to promote cellular growth and the overall HP declined to about 2-3 uW/culture at completion, while HP/cell reveals similar extent as the normal culture (-1DpW). Since only minute amounts of Fr or So is consumed there are inconsequential lactate production and maintained pH. Presumably normal pH in the medium facilitates effective glycogen utilization throughout the study, thereby explaining the maintained HP. Omission of Gln results in a total dissipation of 2 culture; cellular growth is ceased and HP exhibit very low values (-2.5 uW) throughout the study. Most importantly without Gln the glycolytic pathway is apparently inhibited, thus no Gl is consumed and lactate produced. Microcalorimetry seems to serve as a valuable tool to explicate enzyme dependant substrate utilization in face of their thermogenic behaviour. Gln might be considered as an essential nutrient in cell cultures.
NUTRIENT 0.24
A. LEPAPE, P.Y. CARRY, Service
de
INDUCED THERMOGENESI~
(NIT) DURING THE COURSE OF POLYTRAIJMATIZED PATIENTS. J.P. PERDRIX, J.M. GROZEL, v. BANSSILLON.
Reanimation,
Centre
Hospitalier
Lyon-Sud,
France
It has been suggested that NIT in acutely injured patients may be superior in acute phase compared to control. The purpose of the present study is to investigate a possible difference in polytraumatized patients between acute phase (phase A) and recovery phase (phase 8) after a glucose load. Methods : 6 polytraumatized patients were studied. Energy expenditure (EE) was measured continuously (Engstrcm Metabolic Computer) during 3 consecutive periods : fasting state (REE), a 3 hr-continous glucose infusion of 1.5 REE (TO-T1801 and another 3 hrs fasting (T180-T360). Glucose, fatty acid and lactate were determined in serial blood samples, as well as insulin, C-peptid and catecholamines. Leg glb-ose, fatty acid, lactate and 02 A-V differences were mesured (dye dilution method). The same measurements were repeated in recovery phase. Data are mean T S.D. Differences were tested by paired t-teat. Results : REE was inferior in phase B compared to phase A (p < 0.01) confirming the acute nature of phase A. NIT was comparable in the two phases at any time period. For instance at T180, EE was increased of 5.7 % z 3 (A) vs 5.6 % T 1.7 (B), N.S. The
proportion of glucose oxydized compared to the total infused glucose was not different between the two phases (63 % T 38 (A) vs 76 % : 27 (B)-N'S!. 5.2 + 7.9 g ;lucyse was uptaken by the leg during the 6 hrs of the study in the phase A against 7.5 - 3.8 in the phase B, without significative difference. No difference 'was seen between blood hormones during the two phases. In conclusion, in spite of previously published results, N:T In a limited number of PolYtraUmatlZed patients has been found identical In acute an4 recovery nhase.
22
NUTRIENT 1NDUCED THERMOGENESIS IN CELL CULTURES. L. TeJmar-Kolar, J. Nittinger, P. Ftirst, (Inst. Biol. Chem. & N&r., Univ. of Hohenheim, Stuttgart, FRG)
S. Engel,
Microcalorimetry is a new approach to characterize the metabolic activity by direct, continuous and sensitive measurement of the heat production (HP) in cultured cells. The present study was directed to examine the effect of certain energy substrates on nutrient induced thermogenesis in relation to cellular growth and the glycolytic pathway. Microcalorimetry was performed by using an LKB Therm0 Activity Monitor. Peltier elements are sandwiched between the measuring vessel (containing the sample) and tempered heat sinks create a detectable voltage proportional to the temperature difference which is monitored. Previous studies in MOLT 4 suspension culture revealed a high sensitivity of -0.1 uW (lo-'Co) at -10' cell, the reproducibility being 11.6%. In the present study HP was measured over 72 hours in monolayer anaerobic culture of human embryonal lung fibroblasts (IMR-90) cultured in Dulbecco's MEM normally containing suitable amounts of glucose (Gl, lg/l) and glutamine (Gln, 0.58 g/l). In certain experiments Gl was replaced with fructose (Fr) and sorbitol (So) and Gln was alternatively omitted from the medium. The normal course of cellular HP in presence of Gl and Gln at expected cellular growth results in an increase of HP/culture from 6 uW to 9 uW over 72 h, while the HP/cell decreases from 20 pW to 10 pW. Replacement of Gl with Fr or So failed to promote cellular growth and the overall HP declined to about 2-3 uW/culture at completion, while HP/cell reveals similar extent as the normal culture (-1DpW). Since only minute amounts of Fr or So is consumed there are inconsequential lactate production and maintained pH. Presumably normal pH in the medium facilitates effective glycogen utilization throughout the study, thereby explaining the maintained HP. Omission of Gln results in a total dissipation of 2 culture; cellular growth is ceased and HP exhibit very low values (-2.5 uW) throughout the study. Most importantly without Gln the glycolytic pathway is apparently inhibited, thus no Gl is consumed and lactate produced. Microcalorimetry seems to serve as a valuable tool to explicate enzyme dependant substrate utilization in face of their thermogenic behaviour. Gln might be considered as an essential nutrient in cell cultures.
NUTRIENT 0.24
A. LEPAPE, P.Y. CARRY, Service
de
INDUCED THERMOGENESI~
(NIT) DURING THE COURSE OF POLYTRAIJMATIZED PATIENTS. J.P. PERDRIX, J.M. GROZEL, v. BANSSILLON.
Reanimation,
Centre
Hospitalier
Lyon-Sud,
France
It has been suggested that NIT in acutely injured patients may be superior in acute phase compared to control. The purpose of the present study is to investigate a possible difference in polytraumatized patients between acute phase (phase A) and recovery phase (phase 8) after a glucose load. Methods : 6 polytraumatized patients were studied. Energy expenditure (EE) was measured continuously (Engstrcm Metabolic Computer) during 3 consecutive periods : fasting state (REE), a 3 hr-continous glucose infusion of 1.5 REE (TO-T1801 and another 3 hrs fasting (T180-T360). Glucose, fatty acid and lactate were determined in serial blood samples, as well as insulin, C-peptid and catecholamines. Leg glb-ose, fatty acid, lactate and 02 A-V differences were mesured (dye dilution method). The same measurements were repeated in recovery phase. Data are mean T S.D. Differences were tested by paired t-teat. Results : REE was inferior in phase B compared to phase A (p < 0.01) confirming the acute nature of phase A. NIT was comparable in the two phases at any time period. For instance at T180, EE was increased of 5.7 % z 3 (A) vs 5.6 % T 1.7 (B), N.S. The
proportion of glucose oxydized compared to the total infused glucose was not different between the two phases (63 % T 38 (A) vs 76 % : 27 (B)-N'S!. 5.2 + 7.9 g ;lucyse was uptaken by the leg during the 6 hrs of the study in the phase A against 7.5 - 3.8 in the phase B, without significative difference. No difference 'was seen between blood hormones during the two phases. In conclusion, in spite of previously published results, N:T In a limited number of PolYtraUmatlZed patients has been found identical In acute an4 recovery nhase.
22