Factors predicting a successful outcome after pharmacologic bowel compensation.

OBJECTIVES: The authors determined those factors that predict a successful outcome in patients who receive pharmacologic agents to promote bowel absorption after massive intestinal resection. SUMMARY BACKGROUND DATA: Patients with the short bowel syndrome are maintained on long-term total parenteral nutrition (TPN) or more frequently considered for intestinal transplantation as part of their treatment program. The authors have administered a combination of trophic agents and a specialized diet to further enhance intestinal compensation and optimize nutrient absorption in patients with intestinal failure. METHODS: Forty-five TPN-dependent adults with a jejunal-ileal remnant < or = 50 cm and a portion of colon in continuity were treated with growth hormone, glutamine, and a modified diet for 4 weeks and observed for an average of 1.8 years. RESULTS: The average age of the patients was 43 years, the average jejunal-ileal length was 23 cm, and the average length of time the patient received TPN was 4.3 years. After 4 weeks of therapy, 26 (58%) were free of TPN support. Predictors of a favorable response included greater bowel length, lower body weight, and greater bowel length-body weight ratio. At follow-up, the percentage of patients who were not receiving TPN had fallen to 40%. CONCLUSIONS: Approximately half of a group of patients, thought to have absorptive surface area inadequate to be independent of TPN support, can maintain themselves on enteral feedings after this intestinal rehabilitation program. Because of the risk, costs, and alterations in lifestyle associated with long-term TPN or intestinal transplantation or both, it seems prudent to consider a program of bowel rehabilitation with an individual patient before embarking on another therapeutic plan.     

A single dose of endotoxin increases intestinal permeability in healthy humans

To investigate the effects of endotoxin on gut barrier function, we performed paired studies of intestinal permeability in healthy humans (N = 12) receiving intravenous Escherichia coli endotoxin (4 ng/kg) or 0.9% saline solution. Two nonmetabolizable sugars, lactulose and mannitol, which are standard permeability markers, were administered orally, 30 minutes before and 120 minutes after the test injection. The 12-hour urinary excretion of these substances after endotoxin/saline solution administration was used to quantitate intestinal permeability. After endotoxin administration systemic absorption and excretion of lactulose increased almost two-fold (mean +/- SEM, 263 +/- 36 mumol per 12 hours vs 145 +/- 19 mumol per 12 hours during saline studies). Similar but less marked alterations in mannitol absorption and excretion occurred after endotoxin injection (5.7 +/- 0.3 mmol per 12 hours vs 4.9 +/- 0.3 mmol per 12 hours). When individual 12-hour lactulose excretion after endotoxin administration was related to the magnitude of systemic responses, a significant relationship occurred between lactulose excretion and elaboration of norepinephrine and between lactulose excretion and minimum white blood cell count. These data suggest that a brief exposure to circulating endotoxin increases the permeability of the normal gut. These observations are consistent with the hypothesis that during critical illness, prolonged or repeated exposure to systemic endotoxins or associated cytokines may significantly compromise the integrity of the gastrointestinal mucosal barrier.     

Posttraumatic skeletal muscle proteolysis: The role of the hormonal environment

To investigate the role of hormones as mediators of net skeletal muscle proteolysis following injury, healthy normal male volunteers received a continuous 76-hour infusion of the 3 stress hormones: hydrocortisone, glucagon, and epinephrine. As a control, each subject received a saline infusion during another 4-day period. Ten paired studies were conducted. Diets were constant and matched on both occasions. Triple hormone infusion achieved hormone concentrations similar to those seen following mild-moderate injury. After 72 hours of infusion, skeletal muscle intracellular glutamine concentrations were lower in the hormone studies than in the control group (N=4). Free amino acid concentrations in arterial whole blood and forearm amino acid efflux were little affected by hormonal infusion. Thus, alteration of the hormonal environment by the triple hormone infusion was not a sufficient stimulus to induce all of the changes in skeletal muscle proteolysis observed in critical illness. Since studies utilizing neurohormonal blockade have shown diminished net muscle proteolysis, the stress hormones appear to be necessary but not sufficient for the protein catabolic response to injury.

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Resumen Con el propósito de investigar el papel de las hormonas como agentes mediadores de la proteolisis muscular neta que se presenta en el trauma y en otros estados críticos, se administró una infusión de las 3 hormonas del estrés, hidrocortisona, glucagón, y epinefrina, a voluntarios sanos por períodos continuos de 76 horas. Como control, cada individuo recibió una infusión de solución salina durante otro período de 4 días. Se condujeron 10 estudios apareados, con dietas constantes y similares en ambas ocasiones. La infusión triple de hormonas produjo concentraciones sanguíneas hormonales similares a las observadas en pacientes con trauma leve-moderado. A las 72 horas de la infusión las concentraciones intracelulares de glutamina en el mÚsculo esquelético aparecieron menores que en los estudios de control (N=4). Las concentraciones de aminoácidos libres en la sangre arterial y el flujo de salida de aminoácidos en el antebrazo resultaron mínimamente afectados por la infusión hormonal. Por lo tanto, la alteración del medio hormonal producida por infusión triple de hormonas no representa un estímulo suficiente para inducir la totalidad de las alteraciones en la proteolisis del mÚsculo esquelético que se observa en la enfermedad crítica. Puesto que los estudios con bloqueo neurohumoral han demostrado una disminución en la proteolisis muscular neta, las hormonas del estrés parecen ser necesarias, pero no suficientes de por sí, para la respuesta catabólica a la injuria biológica.

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Résumé Pour étudier le rôle des hormones dans la protéolyse posttraumatique de muscle squelettique, des volontaires de sexe mâle en bonne santé ont été perfusés pendant 76 heures avec les 3 hormones de stress: hydrocortisone, glucagon, et adrénaline. En contrôle, chaque patient a reÇu une perfusion de sérum physiologique pendant quatre jours. Dix études appariées ont été faites. Pendant les deux études, l'alimentation était la mÊme et constante. La perfusion des 3 hormones a provoqué une concentration semblable à celle qu'on observe après un traumatisme moyen. Après 72 heures, le taux de glutamine dans les muscles squelettiques était plus bas dans l'étude hormonale que dans l'étude contrôle (N=4). La concentration en acides aminés libres dans le sang artériel et notamment l'arrivée de sang dans l'avant-bras n'étaient que peu influencées par la perfusion hormonale. Ainsi, la perfusion avec augmentation de la concentration des 3 hormones de stress ne suffisait pas pour provoquer la protéolyse musculaire squelettique que l'on observe lors des maladies graves. Puisque d'autres études ont montré que le blocage neurohormonal diminue nettement la protéolyse musculaire, les hormones de stress semblent donc nécessaires mais non suffisantes dans la réponse catabolique protéinique au traumatisme.

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Supported by the National Institutes of Health Trauma Center Grant P50-GM 29327-03 and Clinical Research Center Grant no. 290-9299.     

Hyperphospholipasemia A2 in human volunteers challenged with intravenous endotoxin

Phospholipase A₂ (PLA₂) activity was measured in the serum of 23 individuals infused intravenously with endotoxin (EN) at a dose of 4 ng/kg body weight. A marked increase in PLA₂ was noted 3 h after EN challenge (mean 828 ± 513 units/ml), reached its maximum at 24 h after the challenge (mean 2667 ± 2442 units/ ml), and was still evident at 48 h (mean 763 ± 366 units/ml). In contrast, TNF levels were maximal (mean 712 ± 375 pg/ml) 90 min after the EN challenge and subsided to very low values (5 ± 5 pg/ml) 5 h after the challenge. There was a positive correlation between the maximum response of TNF and that of PLA₂ (r = 0.82,P < 0.01). Administration of ibuprofen or pentoxifylline did not alter the PLA₂ response. EN challenge did not affect serum pancreatic PLA₂ concentration or that of the lysosomal cationic enzyme, lysozyme. Neutralizing antibody against human recombinant (synovial type) PLA₂ completely abolished PLA₂ activity in the sera tested. We conclude that EN infusions cause marked intravascular release of nonpancreatic secretory PLA₂ and that the magnitude of this response seems to be related to the prior generation of TNF.     

Novel scavenger receptor gene is differentially expressed in the embryonic and adult mouse testis.

In an effort to understand the mechanisms that underpin gonadal differentiation at the time of sex determination, we identified a cDNA encoding a putative novel testis expressed scavenger receptor, Tesr. Based on its domain structure, we hypothesize that the function of Tesr is similar to that of other scavenger receptors that play roles in phagocytosis of apoptotic cells, cell-cell adhesion, and defense. Tesr mRNA was detected in fetal mouse gonads of both sexes at 11.5 days post coitum (dpc). From 12.0 dpc, Tesr expression rapidly decreased in the female and was maintained in the male. Expression was seen in embryonic mouse sites other than the testis, such as in brain, eye, head, heart, neural arch, and cartilage primordium. Tesr expression in the newborn testis was faint to undetectable, but it increased from 2 days postpartum (dpp) until 15 dpp and was found in a subset of interstitial cells and in germ and Sertoli cells. Tesr mRNA in the adult mouse testis was observed in Sertoli cells, spermatogonia, spermatocytes, round spermatids, and in a subset of interstitial cells. We conclude that Tesr is differentially expressed in the male vs. female embryonic gonad and is expressed in both the ovary and the testes postnatally after 2 dpp.     

Both inflammatory and endocrine mediators stimulate host responses to sepsis

Host responses to sepsis and trauma are complex and their mediators are not well understood. To examine the roles of "endocrine" and "inflammatory" mediators, we studied healthy volunteers in four experimental groups: continuous 72-hour infusion of normal saline; continuous 72-hour infusion of hydrocortisone, glucagon, and epinephrine; daily intramuscular injection of the inflammatory agent etiocholanolone; and combined etiocholanolone injection--hormone infusion. In this model hypermetabolism, hyperglycemia, hyper-insulinemia, insulin resistance, negative nitrogen balance, and accelerated protein flux were mediated predominantly by infusion of the counterregulatory hormones. Etiocholanolone injection resulted in fever, acute-phase--protein synthesis, and hypoferremia. Leukocyte, temperature, and C-reactive--protein responses reflected major interactions between these stimuli. Both inflammatory and endocrine mediators are necessary for the complete manifestation of host responses to critical illness.     

Therapy which enhances surgical recovery: the potential for multimodality, fast-track surgery in the 21st century

Hospital stay will be greatly reduced following major operations in the years to come. Already, minimally invasive procedures, selected anesthetic techniques and the use of appropriate pharmaceutical agents have reduced postoperative hospitalization. However, surgeons and their anesthesiology colleagues have combined many of these therapies in a multimodality approach, which has greatly shortened surgical convalescence following major surgery. The literature reports that patients can be discharged following recovery in 48 hours following a partial colectomy, in 1-2 days following pneumonectomy and in 4-5 days following knee or hip replacement operations. This multimodality approach appears to greatly reduce postoperative stress. Postoperative hospitalization will continue to be reduced throughout the coming century.     

Metabolic Response to Severe Surgical Illness: Overview

Severe surgical illness results in metabolic responses that mobilize substrate (amino acids and fatty acids) from body stores to support vital organs, enhance resistance to infection, and ensure wound healing. Central to this process is the redistribution of body protein, which moves from skeletal muscle to support the central viscera. If unsupported, this protein-wasting state could result in prolonged convalescence, diminished immunity, and poor wound healing. Present evidence suggests that the central nervous system plays a major role in regulating this protein catabolic response. Infusing exceedingly small quantities of the proinflammatory cytokines into the brain can mimic injury responses, and central cytokine blockade may be one therapeutic approach to attenuating these responses safely in the future. Additional evidence also demonstrates that the function of the hypothalamus and anterior pituitary is dampened during the later stages of severe surgical illness, and the possibility of hormonal replacement therapy needs to be explored.     

Short Bowel Syndrome

Abstract The short bowel syndrome is a symptom complex that occurs in adults who have less than 200 cm of jejunum-ileum remaining after intestinal resection. Similar symptoms are observed in infants and children following massive bowel resection or congenital anomalies and in individuals with longer segments of intestine with severe mucosal disease. Initial care should focus on a thorough excision of nonviable bowel, an exact measurement of the remaining viable bowel, placing all intestine in continuity at the initial or subsequent operation, and controlling initial food intake. With time, adaptation of the remnant intestine occurs, and absorptive function may be maximized by enhancing the enteral diet and minimizing parenteral nutrition. Growth factors and specialized nutrients may also enhance this process. Intestinal transplantation should be considered in selected individuals with the short bowel syndrome who fail intestinal rehabilitation protocols. E-pub: 31 October 2000     

Innate immunity of surfactant protein A and D in urinary tract infection with uropathogenic Escherichia coli

Objective To investigate the role of surfactant protein (SP) - A and SP - D in urinary tract infection mouse model, and evaluate the effects of SP-A and SP-D absence on urinary tract infection. Methods SP-A and SP-D double knockout (SP-A/D KO) mice were made. SP-A/D KO and wild-type (WT) C57BL/6 female mice were used for this study. The expression of SP-A and SP-D in kidney was detected by immunohistochemistry (IHC). The levels of p - p38 and p38 protein in kidneys were measured by Western blotting. Uropathogenic Escherichia coli or buffer was delivered into the bladder of female mice. At 24 and 48 h after inoculation, CFU of Escherichia coli in the kidney and urine of the treated and control mice were measured. Histological, cellular and molecular analysis were performed by several methods of H/E staining, IHC and Western blotting. The effects of SP-A and SP-D on bacterial growth were studied in vitro. Results SP-A and SP-D in kidney were located in the proximal tubules and collecting tubules. Compared with WT mice, infected SP - A/D KO mice with UPEC had higher CFU in kidneys and urine at 24 h and 48 h, increased inflammatory cells infiltration in kidneys（P＜0.05）. Compared with WT mice, SP - A/D KO mice had higher p38 MAPK phosphorylation levels in kidneys（P＜0.05）. Growth of Escherichia coli was greatly inhibited by both SP-A and SP-D（P＜0.05）. Conclusions Both SP-A and SP-D are expressed in kidney. SP-A and SP-D can attenuate UTI induced by UPEC which may be through inhibiting bacterial growth and modulating renal inflammation.