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Low serum leptin levels in crohn disease
GASTROENTEROLOGY Vol. 114, No. 4
A946 AGAABSTRACTS • G3875 THE FORMATION OF A NOVEL CLASS Ib'gp180 COMPLEX ON THE SURFACE OF INTESTINAL EPITHELIAL CELLS TRIGGERS A SIGNALING CASCADE RESULTING IN THE ACTIVATION OF CD8+ SUPPRESSOR T CELLS. N.A. Campbell, S. Balk*, R. Blumberg** and L. Mayer. Division of Clinical Immunology, Mount Sinai Medical Center, New York, NY; *Beth Israel Hospital, Boston, MA; and the **Brigham & Women's Hospital, Boston, MA. Previous studies have shown that intestinal epithelial cells are capable of acting as APCs selectively activating CD8+ suppressor T cells. This activation appears to be mediated by a novel complex consisting of the class Ib molecule CDld and an associated epithelial cell surface glycoprotein, gplS0. We have postulated that this complex is recognized by the TCR:CD8 co-receptor complex on suppressor T cells and serves to induce their activation. Since gpl80 binds to any CD8 molecule, we wanted to determine whether IECs are targeting a selected subpopulation of "pre-suppressor" cells or whether the CDld:gpl80 complex was transducing a specific signal that promoted suppressor cell generation. To accomplish this, we dissected the signaling pathway activated following IEC:T cell co-cultures. Previous studies had shown that both CD8-associated p561ck and TCR-associated p59fyn were activated in these co-cultures. A two-fold experiment was performed: initially, the ability of IECs to activate both lck and fyn was studied in T cell:IEC co-cultures; then, the ability to recruit the protein tyrosine kinase ZAP70 and the proto-oncogenic substrate vav to both fyn and lck was investigated. Both CD8-associated Ick and TCR-associated fyn were activated by IECs. This activation resulted in the recruitment of zeta chain, ZAP70 and vav to fyn while lck associated with ZAP70 and vav. These experiments were then repeated in the presence or absence of an anti-CDld mAb, D5 or an antigpl80 mAb, B9. Activation of fyn but not lck was blocked by D5 while B9 inhibited IEC-induced activation of lck but not fyn. Furthermore, D5 inhibited the ability of ZAP70, zeta and vav to recruit to fyn but not to lck. Conversely, B9 appeared to inhibit the ability of both ZAP70 and vav to be recruited to lck but not fyn. Lastly, MAP kinase was activated in these co-cultures as well, suggesting that the signaling pathway was similar to that of CTLs. These data suggest that the activation of suppressor T ceils is not accomplished through a unique signaling cascade but rather through a similar cascade to cytolytic T cells. This suggests that T cells are committed at an earlier developmental stage to become either suppressor or cytolytic T cells. G3876
EFFECT OF DISEASE LOCALIZATION ON BODY COMPOSITION AND ENERGY METABOLISM IN CROHN'S DISEASE. E. Canristo. Rome, Italy; G. Mingrone, Rome, Italy; G. Addolorato, Rome, Italy; M. Manco, Rome, Italy; A.V. Green, Rome, Italy; G. Gasbarrini, Rome, Italy. Crohn's disease (CD) patients in clinical remission had a low body weight and increased utilization of lipids as energy substrate than ulcerative colitis patients. The aim of this study was to evaluate whether is disease p e r se or disease localization (ileal, ileo-colonic or colonic) to determine these metabolic features of CD. inactive Crohn's disease (CD). Thirty patients with biopsy-proven CD (18 males; age: 34 _+8.0 yrs; BMI: 21.9-+ 2.3 kg/m 2) in clinical remission (SCDAI<3) not receiving steroid therapy or nutritional support were enrolled in the study. Thirty healthy volunteers, matched for age (32-+ 7.5 yrs), sex (18 males) and height (169 ± 7.6 cm) were used as a control group. All patients had a clinical examination and blood samples were collected for the determination of inflammation indexes. Body composition was assessed by both anthropometry and bioimpedance and indirect calorimetry was performed to measure energy expenditure and substrate oxidation rates. Twenty-four-hour urine for the determination of nitrogen excretion and a 7-day food diary were also collected. CD had a lower body weight than both controls (58.1 kg, range 41.5-71.0 vs 66.4 kg, range 57.0-76.0; p<0.001) and UC (58.1 kg, range 41.5-71.0 vs 69.6 kg, range 50.5-94.0; p<0.001). Fat-free mass (FFM) did not differ between the groups, while fat mass was significantly lower in CD than in UC (P<0.05) and controls (p<0.001). Normalising the basal metabolic rate by FFM, a higher value was found in CD compared with controls (151 ± 12.0 kJ/kg vs 136 -+ 9.8 kJ/kg; p<0.01) and significance was reached for every subgroup of patients. The non-protein respiratory quotient value was significantly lower (p<0.01) in each CD subgroup compared to controls (ileal: 0.78 ± 0.03, ileocolonic: 0.79 + 0.04 and colonic: 0.80-+ 0.03, controls: 0.84 -+ 0.03). In conclusion, this study showed that, almost in the inactive form, is CD p e r se, rather than disease localization, to be characterized by peculiar metabolic features, as decreased fat mass content and higher lipid utilization. These findings should represent an important factor to be taken into account in the nutritional management of CD patients, as they frequently showed malnutrition and weight loss also in the remission phase of the disease activity. This work was funded by Ricerca in Medicina, Bologna, Italy.
G3877
EVALUATION OF THE STEROID RESISTANCE IN CROHN'S DISEASE PATIENTS. E. Canristo. Rome, Italy; G. Mingrone, Rome, Italy; M. Pugeat, Lyon, France, A. De Gaetano, Rome, Italy; A. Giancaterini, Rome, Italy; A. V. Green, Rome, Italy; G. Gasbarrini, Rome, Italy. A partial or complete steroid resistance, whose cause is not yet clarified, has been documented in many patients with long-standing Crohn's disease (CD). The primary aim of this study was to evaluate the number and affinity of serum protein steroid-binding sites in steroid-resistant Crohn's patients. A secondary goal was to measure insulin sensitivity, an indirect index of steroid effectiveness, in these patients. Eight male steroid-resistant patients with active ileal CD (CDAI<150) and 6 male healthy volunteers, matched for age (30--. 4.5 yrs) and height (170 -+6.7 cm) were studied. Corticosteroid Binding Globulin (CBG) binding capacity and affinity for cortisol were measured. The binding of cortisol to normal human serum and to serum of patients with CD was also determined. Whole body glucose uptake and oxidation were assessed by euglycemic hyperinsulinemic clamp and indirect calorimetry. Crohn's patients showed a significantly greater capacity of serum albumin for cortisol than controls (by about 40%, or about 0.15 moles per mole). Conversely, the binding of cortisol to CBG did not show significant differences between groups. Glucose uptake was higher in Crohn's patients than in normal controls (8.82 -+ 2.50 vs 7.01 - 2.24 mg/kgFFM/min; p=0.036). Basal serum Non-Esterified Fatty Acid (NEFA) levels were lower in patients than in controls (459.64-+69.95 vs 1026.48+ 112.58 laM; p= 0.002). The observed increase in albumin binding might limit the bioactivity of cortisol in Crohn's patients and contribute to the decreased effectiveness and weaker side effects of glucocorticoid therapy in these patients. The increased number of cortisol binding sites on albumin from patients with CD might be correlated with the significant decrease in serum NEFA, which may compete with steroids for the same sites. This work was funded by Ricerea in Medicina, Bologna, Italy. G3878
LOW SERUM LEPTIN LEVELS IN CROHN DISEASE, E. Canristo. Rome, Italy; A. V. Green, Rome, Italy; G. Mingrone, Rome, Italy; *A. Pietrobelli, New York, NY; *J. Wang, New York, NY; *S.B. Heymsfield, New York, NY; G. Gasbarrini, Rome, Italy. Malnutrition and fat mass reduction are typical features of Crohn's disease patients (CD). Leptin, a protein encoded by the ob gene, regulates food intake and correlates with body fat. This study aimed to evaluate body composition, serum leptin concentration, energy balance in 23 ileal CD (13 males, age 31 _+ 10.2 yrs, height: 169-+7.6 cm) in clinical remission (CDAI<150) and not receiving steroid therapy, comparing them with a group of 20 healthy subjects matched for sex (12 males), age (32 -+ 10 yrs), and height (168 -+7.6 cm). Body composition was assessed by the isotopic diluition technique. Serum leptin concentration was determined by specific radioimmunoassay. Blood samples were drawn upon admission for the determination of inflammatory indexes and 24-h urinary nitrogen excretion was determined. Basal metabolic rate (BMR) and substrate oxidation rate were measured by indirect calorimetry and a seven-day food diary was collected. CD patients showed reduced body weight and fat mass (FM, kg and %), but similar fatfree mass (FFM, kg and %) compared with controls. Serum leptin concentration was significantly lower in CD than controls, correlating in both groups only to FM (kg) (CD: R=0.35; p<0.01; controls: R=0.33; p<0.01) and FM (%) (CD: R=0.45;p<0.01; controls: R=0.39; p<0.01). No difference in BMR and energy intake waS found between groups. CD patients showed a lower non-protein RQ value compared to control subjects (0.78 - 0.03 vs 0.84 -+0.04; p<0.01), indicating a preferential lipid oxidation rate in these patients. Body BMI Fat mass Serumleptin EI weight(kg) (kg/m2) (%) (ng/ml) (kJ/day) CD (n=20) 61.1_+8.7" 21.3±2.0" 20.0±5.84* 4.4(h:2.29"* 7940a:840 Controls(n=20) 66.8_+8.1 23.5_+1.5 25.3_+6.72 9.66+_5.20 7690-+953 CD: Crohn'sdisease;El: Energyintake. *: p < 0.05; ** p < 0.(301 vs. controls. CD patients in clinical remission had a low body weight and fat mass and an enhanced utilization of lipids as fuel substrate than control subjects. Low serum leptin levels in these patients seemed to be related to reduced fat mass rather than to body weight or energy intake. This work was funded by Ricerca in Medicina, Bologna, Italy. • G3879 BODY COMPOSITION AND MECHANISMS OF WEIGHT GAIN IN HIV-INFECTED MALNOURISHED PATIENTS TREATED WITH INDINAVIR. Carbonnel F, Maslo C, Beaugerie L, Aussel C, Gobert JG, Girard PM, Gendre JP, Rozenbaum W et Cosnes J. Services de Gastroentrrologie-Nutrition et Maladies Infectieuses, Hrpital Rothschild; Laboratoire de Biochimie, Hrpital Saint Antoine; Laboratoire de Coprologie Fonctionnelle, H6pital de La Salp~tri~re, Paris. Introduction. The objectives of this study were : a) study the effect of indinavir on body composition of HIV-infected malnourished patients; b) assess the mechanisms of body weight gain. Methods. 16 malnourished
A946 AGAABSTRACTS • G3875 THE FORMATION OF A NOVEL CLASS Ib'gp180 COMPLEX ON THE SURFACE OF INTESTINAL EPITHELIAL CELLS TRIGGERS A SIGNALING CASCADE RESULTING IN THE ACTIVATION OF CD8+ SUPPRESSOR T CELLS. N.A. Campbell, S. Balk*, R. Blumberg** and L. Mayer. Division of Clinical Immunology, Mount Sinai Medical Center, New York, NY; *Beth Israel Hospital, Boston, MA; and the **Brigham & Women's Hospital, Boston, MA. Previous studies have shown that intestinal epithelial cells are capable of acting as APCs selectively activating CD8+ suppressor T cells. This activation appears to be mediated by a novel complex consisting of the class Ib molecule CDld and an associated epithelial cell surface glycoprotein, gplS0. We have postulated that this complex is recognized by the TCR:CD8 co-receptor complex on suppressor T cells and serves to induce their activation. Since gpl80 binds to any CD8 molecule, we wanted to determine whether IECs are targeting a selected subpopulation of "pre-suppressor" cells or whether the CDld:gpl80 complex was transducing a specific signal that promoted suppressor cell generation. To accomplish this, we dissected the signaling pathway activated following IEC:T cell co-cultures. Previous studies had shown that both CD8-associated p561ck and TCR-associated p59fyn were activated in these co-cultures. A two-fold experiment was performed: initially, the ability of IECs to activate both lck and fyn was studied in T cell:IEC co-cultures; then, the ability to recruit the protein tyrosine kinase ZAP70 and the proto-oncogenic substrate vav to both fyn and lck was investigated. Both CD8-associated Ick and TCR-associated fyn were activated by IECs. This activation resulted in the recruitment of zeta chain, ZAP70 and vav to fyn while lck associated with ZAP70 and vav. These experiments were then repeated in the presence or absence of an anti-CDld mAb, D5 or an antigpl80 mAb, B9. Activation of fyn but not lck was blocked by D5 while B9 inhibited IEC-induced activation of lck but not fyn. Furthermore, D5 inhibited the ability of ZAP70, zeta and vav to recruit to fyn but not to lck. Conversely, B9 appeared to inhibit the ability of both ZAP70 and vav to be recruited to lck but not fyn. Lastly, MAP kinase was activated in these co-cultures as well, suggesting that the signaling pathway was similar to that of CTLs. These data suggest that the activation of suppressor T ceils is not accomplished through a unique signaling cascade but rather through a similar cascade to cytolytic T cells. This suggests that T cells are committed at an earlier developmental stage to become either suppressor or cytolytic T cells. G3876
EFFECT OF DISEASE LOCALIZATION ON BODY COMPOSITION AND ENERGY METABOLISM IN CROHN'S DISEASE. E. Canristo. Rome, Italy; G. Mingrone, Rome, Italy; G. Addolorato, Rome, Italy; M. Manco, Rome, Italy; A.V. Green, Rome, Italy; G. Gasbarrini, Rome, Italy. Crohn's disease (CD) patients in clinical remission had a low body weight and increased utilization of lipids as energy substrate than ulcerative colitis patients. The aim of this study was to evaluate whether is disease p e r se or disease localization (ileal, ileo-colonic or colonic) to determine these metabolic features of CD. inactive Crohn's disease (CD). Thirty patients with biopsy-proven CD (18 males; age: 34 _+8.0 yrs; BMI: 21.9-+ 2.3 kg/m 2) in clinical remission (SCDAI<3) not receiving steroid therapy or nutritional support were enrolled in the study. Thirty healthy volunteers, matched for age (32-+ 7.5 yrs), sex (18 males) and height (169 ± 7.6 cm) were used as a control group. All patients had a clinical examination and blood samples were collected for the determination of inflammation indexes. Body composition was assessed by both anthropometry and bioimpedance and indirect calorimetry was performed to measure energy expenditure and substrate oxidation rates. Twenty-four-hour urine for the determination of nitrogen excretion and a 7-day food diary were also collected. CD had a lower body weight than both controls (58.1 kg, range 41.5-71.0 vs 66.4 kg, range 57.0-76.0; p<0.001) and UC (58.1 kg, range 41.5-71.0 vs 69.6 kg, range 50.5-94.0; p<0.001). Fat-free mass (FFM) did not differ between the groups, while fat mass was significantly lower in CD than in UC (P<0.05) and controls (p<0.001). Normalising the basal metabolic rate by FFM, a higher value was found in CD compared with controls (151 ± 12.0 kJ/kg vs 136 -+ 9.8 kJ/kg; p<0.01) and significance was reached for every subgroup of patients. The non-protein respiratory quotient value was significantly lower (p<0.01) in each CD subgroup compared to controls (ileal: 0.78 ± 0.03, ileocolonic: 0.79 + 0.04 and colonic: 0.80-+ 0.03, controls: 0.84 -+ 0.03). In conclusion, this study showed that, almost in the inactive form, is CD p e r se, rather than disease localization, to be characterized by peculiar metabolic features, as decreased fat mass content and higher lipid utilization. These findings should represent an important factor to be taken into account in the nutritional management of CD patients, as they frequently showed malnutrition and weight loss also in the remission phase of the disease activity. This work was funded by Ricerca in Medicina, Bologna, Italy.
G3877
EVALUATION OF THE STEROID RESISTANCE IN CROHN'S DISEASE PATIENTS. E. Canristo. Rome, Italy; G. Mingrone, Rome, Italy; M. Pugeat, Lyon, France, A. De Gaetano, Rome, Italy; A. Giancaterini, Rome, Italy; A. V. Green, Rome, Italy; G. Gasbarrini, Rome, Italy. A partial or complete steroid resistance, whose cause is not yet clarified, has been documented in many patients with long-standing Crohn's disease (CD). The primary aim of this study was to evaluate the number and affinity of serum protein steroid-binding sites in steroid-resistant Crohn's patients. A secondary goal was to measure insulin sensitivity, an indirect index of steroid effectiveness, in these patients. Eight male steroid-resistant patients with active ileal CD (CDAI<150) and 6 male healthy volunteers, matched for age (30--. 4.5 yrs) and height (170 -+6.7 cm) were studied. Corticosteroid Binding Globulin (CBG) binding capacity and affinity for cortisol were measured. The binding of cortisol to normal human serum and to serum of patients with CD was also determined. Whole body glucose uptake and oxidation were assessed by euglycemic hyperinsulinemic clamp and indirect calorimetry. Crohn's patients showed a significantly greater capacity of serum albumin for cortisol than controls (by about 40%, or about 0.15 moles per mole). Conversely, the binding of cortisol to CBG did not show significant differences between groups. Glucose uptake was higher in Crohn's patients than in normal controls (8.82 -+ 2.50 vs 7.01 - 2.24 mg/kgFFM/min; p=0.036). Basal serum Non-Esterified Fatty Acid (NEFA) levels were lower in patients than in controls (459.64-+69.95 vs 1026.48+ 112.58 laM; p= 0.002). The observed increase in albumin binding might limit the bioactivity of cortisol in Crohn's patients and contribute to the decreased effectiveness and weaker side effects of glucocorticoid therapy in these patients. The increased number of cortisol binding sites on albumin from patients with CD might be correlated with the significant decrease in serum NEFA, which may compete with steroids for the same sites. This work was funded by Ricerea in Medicina, Bologna, Italy. G3878
LOW SERUM LEPTIN LEVELS IN CROHN DISEASE, E. Canristo. Rome, Italy; A. V. Green, Rome, Italy; G. Mingrone, Rome, Italy; *A. Pietrobelli, New York, NY; *J. Wang, New York, NY; *S.B. Heymsfield, New York, NY; G. Gasbarrini, Rome, Italy. Malnutrition and fat mass reduction are typical features of Crohn's disease patients (CD). Leptin, a protein encoded by the ob gene, regulates food intake and correlates with body fat. This study aimed to evaluate body composition, serum leptin concentration, energy balance in 23 ileal CD (13 males, age 31 _+ 10.2 yrs, height: 169-+7.6 cm) in clinical remission (CDAI<150) and not receiving steroid therapy, comparing them with a group of 20 healthy subjects matched for sex (12 males), age (32 -+ 10 yrs), and height (168 -+7.6 cm). Body composition was assessed by the isotopic diluition technique. Serum leptin concentration was determined by specific radioimmunoassay. Blood samples were drawn upon admission for the determination of inflammatory indexes and 24-h urinary nitrogen excretion was determined. Basal metabolic rate (BMR) and substrate oxidation rate were measured by indirect calorimetry and a seven-day food diary was collected. CD patients showed reduced body weight and fat mass (FM, kg and %), but similar fatfree mass (FFM, kg and %) compared with controls. Serum leptin concentration was significantly lower in CD than controls, correlating in both groups only to FM (kg) (CD: R=0.35; p<0.01; controls: R=0.33; p<0.01) and FM (%) (CD: R=0.45;p<0.01; controls: R=0.39; p<0.01). No difference in BMR and energy intake waS found between groups. CD patients showed a lower non-protein RQ value compared to control subjects (0.78 - 0.03 vs 0.84 -+0.04; p<0.01), indicating a preferential lipid oxidation rate in these patients. Body BMI Fat mass Serumleptin EI weight(kg) (kg/m2) (%) (ng/ml) (kJ/day) CD (n=20) 61.1_+8.7" 21.3±2.0" 20.0±5.84* 4.4(h:2.29"* 7940a:840 Controls(n=20) 66.8_+8.1 23.5_+1.5 25.3_+6.72 9.66+_5.20 7690-+953 CD: Crohn'sdisease;El: Energyintake. *: p < 0.05; ** p < 0.(301 vs. controls. CD patients in clinical remission had a low body weight and fat mass and an enhanced utilization of lipids as fuel substrate than control subjects. Low serum leptin levels in these patients seemed to be related to reduced fat mass rather than to body weight or energy intake. This work was funded by Ricerca in Medicina, Bologna, Italy. • G3879 BODY COMPOSITION AND MECHANISMS OF WEIGHT GAIN IN HIV-INFECTED MALNOURISHED PATIENTS TREATED WITH INDINAVIR. Carbonnel F, Maslo C, Beaugerie L, Aussel C, Gobert JG, Girard PM, Gendre JP, Rozenbaum W et Cosnes J. Services de Gastroentrrologie-Nutrition et Maladies Infectieuses, Hrpital Rothschild; Laboratoire de Biochimie, Hrpital Saint Antoine; Laboratoire de Coprologie Fonctionnelle, H6pital de La Salp~tri~re, Paris. Introduction. The objectives of this study were : a) study the effect of indinavir on body composition of HIV-infected malnourished patients; b) assess the mechanisms of body weight gain. Methods. 16 malnourished