Sequential changes in insulin-like growth factor 1, plasma proteins, and total body protein in severe sepsis and multiple injury

Does hypometabolism constrain innate immune defense?

Many animals routinely make energetic trade-offs to adjust to environmental demands and these trade-offs often have significant implications for survival. For example, environmental hypoxia is commonly experienced by many organisms and is an energetically challenging condition because reduced oxygen availability constrains aerobic energy production, which can be lethal. Many hypoxia-tolerant species downregulate metabolic demands when oxygen is limited; however, certain physiological functions are obligatory and must be maintained despite the need to conserve energy in hypoxia. Of particular interest is immunity (including both constitutive and induced immune functions) because mounting an immune response is among the most energetically expensive physiological processes but maintaining immune function is critical for survival in most environments. Intriguingly, physiological responses to hypoxia and pathogens share key molecular regulators such as hypoxia-inducible factor-1α, through which hypoxia can directly activate an immune response. This raises an interesting question: do hypoxia-tolerant species mount an immune response during periods of hypoxia-induced hypometabolism? Unfortunately, surprisingly few studies have examined interactions between immunity and hypometabolism in such species. Therefore, in this review, we consider mechanistic interactions between metabolism and immunity, as well as energetic trade-offs between these two systems, in hypoxia-tolerant animals but also in other models of hypometabolism, including neonates and hibernators. Specifically, we explore the hypothesis that such species have blunted immune responses in hypometabolic conditions and/or use alternative immune pathways when in a hypometabolic state. Evidence to date suggests that hypoxia-tolerant animals do maintain immunity in low oxygen conditions, but that the sensitivity of immune responses may be blunted.

Changes in serum prealbumin as a marker for nitrogen balance in surgical oncology patients

BACKGROUND

Serum prealbumin has long been used as a marker of nutritional status. However, prealbumin is a negative acute phase reactant influenced by several non-nutritional-related factors including surgery, infection, and cancer. An increasing prealbumin has been correlated with a positive nitrogen balance in general surgery patients receiving parenteral nutrition (PN) with 88% specificity and 70% sensitivity. To date, no trial has evaluated the effect of concurrent cancer and surgery on the value of prealbumin in predicting nitrogen balance.

METHODS

This study is a concurrent retrospective design of post-operative patients (≥ 19 years of age) identified by the nutrition support service who received PN for ≥ 5 days, had a baseline and follow-up serum prealbumin and C-reactive Protein (CRP) measured, as well as a 24-h urinary urea nitrogen (UUN) performed between days 5-10 of PN. Exclusion criteria include anuric renal failure, Child-Pugh Class C liver failure, pregnancy, and corticosteroid use. Prealbumin was correlated to nitrogen balance, measuring sensitivity, specificity, and negative and positive predictive values. Information was collected regarding patient demographics and presence or absence of metastatic cancer.

RESULTS

Thirty patients were identified and evaluated for this study from December 1st, 2010 to July 15th, 2011. Patients included in the study had a mean age of 57 years old (range 20-82), 53% male, with a mean weight of 84 kg (range 42-140) and body mass index (BMI) of 29 kg/m2 (range 14.9-56.8). The mean daily caloric dose of PN per actual body weight was 21 kcal/kg (range 10-34) and the mean daily protein dose was 1.4 g/kg (range 1-2). Forty seven percent of patients were obese (BMI > 30 kg/m2) and were prescribed high-protein hypocaloric PN. The most common indication for PN was post-operative ileus (23/30 patients). 24-h urine collection for UUN was performed on average of day 8 after PN initiation (range 5-10 days). Nitrogen balance as calculated from 24-h UUN was positive in 17/30 patients. A positive prealbumin change of greater than 2.8 mg/dL was found to have a statistically significant association with positive nitrogen balance (p = 0.02). At the cut off level of positive 2.8 mg/dL, the likelihood of a positive nitrogen balance had a sensitivity of 82% (95% confidence interval (CI) 64-100%); specificity of 62% (95% CI 35-88%); positive predictive value of 74% (95% CI 54-93%); negative predictive value of 73% (95% CI 46-99%). No absolute value for prealbumin level (e.g., > 20  mg/dL) was found to be a significant predictor of positive nitrogen balance. CRP levels at initiation of PN were significantly elevated with a mean level of 147 mg/dL.

CONCLUSION

These results indicate a positive change in serum prealbumin (> 2.8 mg/dL) has sufficient sensitivity (82%) to predict positive changes in nitrogen balance in the surgical oncology population. However, the low specificity (62%) makes it less useful in predicting a negative nitrogen balance. Absolute prealbumin levels were greatly affected by inflammation, as evidenced by CRP levels, and single values were not useful in predicting positive nitrogen balance.

CLINICAL RELEVANCY

Positive changes in serum prealbumin levels have previously been associated with a positive nitrogen balance (NB) in surgical patients receiving parenteral nutrition (PN); however, it is unclear if this is true in oncologic surgery patients. This study highlights how changing levels of serum prealbumin and C-reactive protein correlates to NB for cancer patients in the post-operative period requiring PN. Changes in prealbumin levels from baseline showed sufficient sensitivity, but not specificity to utilize routinely for predicting NB in this population.

TGF – beta 2 enriched formula as oral nutritional supplement in patients hospitalized for COVID-19: A preliminary observational study

BACKGROUND: SARS-COV 2 turned in a global epidemic since January 2020. It is able to directly stimulate the release of proinflammatory cytokines (cytokine storm) and, affecting enterocytis, dysregulates intestinal permeability likewise Inflammatory Bowel Diseases. According to Guidelines, nutritional support in COVID-19 patients is relevant in a perspective of a fast recovery. Aim of this study is to propose in SARS-COV2 patients an early nutritional support using a polymeric - TGF-beta2 containing formula, with immunoregulatory properties specific for bowel disease, evaluating its effects on systemic inflammation and protein energy malnutrition. METHODS: COVID-19 patients hospitalized in Santa Maria Hospital of Terni and in Madonna delle Grazie Hospital of Matera (March - December 2020) were enrolled. The protocol consists in supplying 150 gr of nutritional formula powder (750 kcal/day). Values of serum prealbumin, transferrin, C-reactive protein and Lymphocyte count were collected at baseline and every week. Data were compared to a untreated sample of inpatients. RESULTS: TGF-beta2 containing formula use seems to be associated to a lower needing and longer time free from steroid therapy, increasing of prealbumin and transferrin values and overall with a better outcome in exposed patients; higher values of serum prealbumin seemed to be associated with lower CRP. It does not induce gastrointestinal discomfort or worsen gastrointestinal symptoms. CONCLUSIONS: TGF-beta2 containing formula represents a valid nutritional support in COVID-19, preventing sarcopenia associated to hypercatabolic status and modulating inflammatory response probably thanks to specific properties of its nutritional components. This is only a preliminary observation: further investigations are on-going, involving several Italian Centers.

Urinary Proteomic Signature in Acute Decompensated Heart Failure: Advances into Molecular Pathophysiology

Acute decompensated heart failure (ADHF) is a life-threatening clinical syndrome involving multi-organ function deterioration. ADHF results from multifaceted, dysregulated pathways that remain poorly understood. Better characterization of proteins associated with heart failure decompensation is needed to gain understanding of the disease pathophysiology and support a more accurate disease phenotyping. In this study, we used an untargeted mass spectrometry (MS) proteomic approach to identify the differential urine protein signature in ADHF patients and examine its pathophysiological link to disease evolution. Urine samples were collected at hospital admission and compared with a group of healthy subjects by two-dimensional electrophoresis coupled to MALDI-TOF/TOF mass spectrometry. A differential pattern of 26 proteins (>1.5-fold change, p < 0.005), mostly of hepatic origin, was identified. The top four biological pathways (p < 0.0001; in silico analysis) were associated to the differential ADHF proteome including retinol metabolism and transport, immune response/inflammation, extracellular matrix organization, and platelet degranulation. Transthyretin (TTR) was the protein most widely represented among them. Quantitative analysis by ELISA of TTR and its binding protein, retinol-binding protein 4 (RBP4), validated the proteomic results. ROC analysis evidenced that combining RBP4 and TTR urine levels highly discriminated ADHF patients with renal dysfunction (AUC: 0.826, p < 0.001) and significantly predicted poor disease evolution over 18-month follow-up. In conclusion, the MS proteomic approach enabled identification of a specific urine protein signature in ADHF at hospitalization, highlighting changes in hepatic proteins such as TTR and RBP4.

Caloric adequacy of parenteral nutrition and its influence on the clinical outcome of hospitalised patients

Background: The adaptation of Parenteral Nutrition (PN) to actual energy requirements of hospitalised patients is essential, since excessive and insufficient nutritional intake have been associated with poor clinical outcomes. Aim: To evaluate the adaptation of prescribed PN to the estimated nutritional requirements using three predictive equations and the influence of excessive/insufficient nutrient intake on patient clinical outcomes (nutritional parameters, metabolic and infectious complications). Methods: Prospective, observational study in hospitalised patients nutritionally assessed. Data was collected the first and fifth/sixth day of PN with clinical (infection, length of hospital stay), biochemical (visceral proteins, cholesterol, glucose, triglycerides, lymphocytes, CRP) and anthropometric parameters (skin folds, height, weight). Theoretical requirements were calculated using Harris-Benedict (HB), Mifflin-St Jeor (MF) and 25 Kcal/Kg/day formulas. The HB formula was used to compare estimated and provided requirements. Results: A total of 94 patients (mean: 72 ± 13.7 years old) were included with initial mean weight and height of 69.2 Kg and 162.8 cm, respectively (mean BMI: 26.1 Kg/m²). No statistically significant differences were found between the actual (1620 Kcal/day) and estimated caloric mean calculated with HB (1643 Kcal/day) and MF (1628 Kcal/day). When comparing with the caloric estimation, 31.9% of patients were underfed, while 14.9% were overfed. Intergroup analysis demonstrated significant variations in albumin, prealbumin, glucose, cholesterol, triglycerides and MUAC, with a significant increase of hyperglycaemia (+37.86; p < 0.05) and hypertriglyceridemia (+63.10; p < 0.05), being higher in overfed patients. Conclusion: In our study, inadequate nutrient intake was associated with a higher degree of hyperglycaemia and hypertriglyceridemia, without positive impact on anthropometric parameters.

Associations of serum transthyretin with triglyceride in non-obese elderly Japanese women independently of insulin resistance, HDL cholesterol, and adiponectin

Objective

Studies are limited on the association between serum transthyretin (TTR), a negative acute phase reactant, and triglyceride (TG).

Research design and methods

TG, TTR, and insulin resistance-related cardiometabolic variables were measured in 159 fasting and 185 nonfasting community-dwelling elderly women aged 50-96 years. Pearson correlation analysis and then stepwise multiple regression analyses were performed to further identify the most significant variables contributing to the variation of fasting and nonfasting TG.

Results

Multiple regression analysis for fasting TG as a dependent variable revealed that TTR (standardized β: 0.299) and HDL cholesterol (standardized β: -0.545) emerged as determinants of TG independently of percentage of body fat, homeostasis model assessment insulin resistance, serum leptin and adiponectin, and plasminogen activator inhibitor-1 (PAI-1) (R ² = 0.36). For nonfasting TG, HDL cholesterol (standardized β: - 0.461), TTR (standardized β: 0.231), nonfasting insulin, a marker of insulin resistance, (standardized β: 0.202), and PAI-1 (standardized β: 0.187) emerged as determinants independently of percentage of body fat, nonfasting glucose, serum leptin and adiponectin, and high-sensitivity C-reactive protein (R ² = 0.45).

Conclusions

Fasting and nonfasting TG showed positive association with TTR in community-dwelling elderly non-obese women independently of insulin resistance, HDL cholesterol, and adiponectin. These findings may provide a clue as to a physiological function of circulating TTR in human: an influence factor of TG-rich lipoproteins in the circulation.

The Use of Visceral Proteins as Nutrition Markers: An ASPEN Position Paper

Serum albumin and prealbumin, well-known visceral proteins, have traditionally been considered useful biochemical laboratory values in a nutrition assessment. However, recent literature disputes this contention. The aim of this document is to clarify that these proteins characterize inflammation rather than describe nutrition status or protein-energy malnutrition. Both critical illness and chronic illness are characterized by inflammation and, as such, hepatic reprioritization of protein synthesis occurs, resulting in lower serum concentrations of albumin and prealbumin. In addition, the redistribution of serum proteins occurs because of an increase in capillary permeability. There is an association between inflammation and malnutrition, however, not between malnutrition and visceral-protein levels. These proteins correlate well with patients' risk for adverse outcomes rather than with protein-energy malnutrition. Therefore, serum albumin and prealbumin should not serve as proxy measures of total body protein or total muscle mass and should not be used as nutrition markers. This paper has been approved by the American Society for Parenteral and Enteral Nutrition Board of Directors.

Nutrients and Porphyria: An Intriguing Crosstalk

Porphyria refers to a group of fascinating diseases from a metabolic and nutritional standpoint as it provides an example of how metabolic manipulation can be used for therapeutic purposes. It is characterized by defects in heme synthesis, particularly in the erythrocytes and liver. Specific enzymes involved in heme biosynthesis directly depend on adequate levels of vitamins and minerals in the tissues. Moreover, micronutrients that are required for producing succinyl CoA and other intermediates in the Krebs (TCA) cycle are indirectly necessary for heme metabolism. This review summarizes articles that describe the nutritional status, supplements intake, and dietary practices of patients affected by porphyria, paying special attention to the therapeutic use of nutrients that may help or hinder this group of diseases.

Non-islet Cell Hypoglycemia: Case Series and Review of the Literature

Non-islet cell hypoglycemia (NICH) is hypoglycemia due to the overproduction of insulin-like growth factor-2 (IGF-2) and its precursors which can activate the insulin receptor. Typically, large mesenchymal and epithelial tumors can cause NICH. Diagnosis is confirmed by finding an elevated IGF-2/IGF-1 ratio. The mainstay of treatment is surgical excision. Glucocorticoids may be used in cases where surgery is not possible. We present two cases of NICH with different outcomes. A 33-year-old male patient admitted with altered mental. He was found walking naked outside his house. Laboratory assessment revealed severe hypoglycemia. Further evaluation showed low levels of insulin, C-peptide, and beta-hydroxybutyrate along with an elevated IGF-2/IGF-1 ratio confirming the diagnosis of NICH. Computed tomography (CT) of the abdomen showed a massive tumor of the liver consistent with hepatocellular carcinoma. Since the patient refused surgery, he was started on prednisone however the hypoglycemia persisted. A 54-year-old female patient with a history of type 2 diabetes mellitus (DM) admitted with recent onset hypoglycemia. Despite stopping her insulin, she continued to have hypoglycemia necessitating the administration of high concentrations of intravenous dextrose. Further evaluation showed low levels of insulin, C-peptide, and beta-hydroxybutyrate along with an elevated IGF-2/IGF-1 ratio consistent with the diagnosis of NICH. CT abdomen showed a 24 cm tumor near the uterus. The pathology was consistent with a gastrointestinal stromal tumor (GIST). After surgical excision of the tumor, the hypoglycemia resolved.

Development of a Physiologically Based Pharmacokinetic Modelling Approach to Predict the Pharmacokinetics of Vancomycin in Critically Ill Septic Patients

BACKGROUND AND OBJECTIVES

Sepsis is characterised by an excessive release of inflammatory mediators substantially affecting body composition and physiology, which can be further affected by intensive care management. Consequently, drug pharmacokinetics can be substantially altered. This study aimed to extend a whole-body physiologically based pharmacokinetic (PBPK) model for healthy adults based on disease-related physiological changes of critically ill septic patients and to evaluate the accuracy of this PBPK model using vancomycin as a clinically relevant drug.

METHODS

The literature was searched for relevant information on physiological changes in critically ill patients with sepsis, severe sepsis and septic shock. Consolidated information was incorporated into a validated PBPK vancomycin model for healthy adults. In addition, the model was further individualised based on patient data from a study including ten septic patients treated with intravenous vancomycin. Models were evaluated comparing predicted concentrations with observed patient concentration-time data.

RESULTS

The literature-based PBPK model correctly predicted pharmacokinetic changes and observed plasma concentrations especially for the distribution phase as a result of a consideration of interstitial water accumulation. Incorporation of disease-related changes improved the model prediction from 55 to 88% within a threshold of 30% variability of predicted vs. observed concentrations. In particular, the consideration of individualised creatinine clearance data, which were highly variable in this patient population, had an influence on model performance.

CONCLUSION

PBPK modelling incorporating literature data and individual patient data is able to correctly predict vancomycin pharmacokinetics in septic patients. This study therefore provides essential key parameters for further development of PBPK models and dose optimisation strategies in critically ill patients with sepsis.

Elevated serum adiponectin and tumor necrosis factor-α and decreased transthyretin in Japanese elderly women with low grip strength and preserved muscle mass and insulin sensitivity

OBJECTIVE

To determine if adiponectin levels are associated with low grip strength among the elderly independently of insulin resistance and inflammation.

RESEARCH DESIGN AND METHODS

Cross-sectional associations were analyzed by logistic regression between low grip strength and body composition, elevated serum adiponectin (≥20 mg/L), and biomarkers of nutritious stasis, insulin resistance and inflammation in 179 community-living Japanese women. Sarcopenia was evaluated using the Asian criteria.

RESULTS

No women had sarcopenia. In bivariate analyses, low grip strength (n=68) was positively associated with age, log tumor necrosis factor-α (TNF-α) and hyperadiponectinemia (n=37) and inversely with body weight, height, skeletal muscle mass, serum albumin, transthyretin (TTR), fat mass, serum zinc and hemoglobin (all p<0.01). In a fully adjusted model, TTR (0.90: 0.83-0.98, p=0.01) in addition to age (p=0.007), height (p=0.004) and skeletal muscle mass (p=0.008) emerged as independent determinants of low grip strength. When TTR was removed from the full model, TNF-α was associated with low grip strength (7.7; 1.3-45.8, p=0.02). Mean waist circumference and high-density lipoprotein cholesterol did not differ between women with and without low grip strength and were within the respective normal range. Women with hyperadiponectinemia had higher percentage of women with low grip strength and lower grip strength (both p<0.01).

CONCLUSIONS

Hyperadiponectinemia and elevated TNF-α in addition to decreased TTR, a biomarker of age-related catabolic states, were found in community-living Japanese elderly women with low grip strength and preserved muscle mass and insulin sensitivity.

Monitoring Nutrition in Critical Illness: What Can We Use?

BACKGROUND

Nutrition monitoring in the context of critical care presents unique challenges. Traditionally used anthropometric and biochemical markers may be difficult to obtain or confounded by factors such as fluid status and the inflammatory response. A previous survey identified 15 parameters in common use, all of which have confounding influences during critical illness.

MATERIALS AND METHODS

A literature search was conducted to assess current use of commonly used nutrition-monitoring parameters and to explore other possible methods that might be more useful. More than 1000 journal articles were reviewed to identify indicators of nutrition status or nutrition progress that have been used in ICU studies. The most recent 200 articles were examined to quantify the number of occurrences for each indicator. Each parameter was rated for availability and feasibility in the ICU.

RESULTS

There were 53 parameters found, including the 15 already identified as commonly used; 27 were used in ≥3 recent studies. Less-well-established nutrition indicators with potential for use in the ICU (moderate or high feasibility and availability) included ultrasound measurement of arm or leg muscle thickness, fatigue scoring with the Chalder scale, urinary creatinine assay, and serum insulin-like growth factor 1 level. None of these was among the commonly used indicators in recent studies.

CONCLUSION

This study identifies commonly used nutrition-monitoring parameters and discusses their feasibility and availability in the critical care setting. Further investigation of nutrition indicators in ICU is needed, ideally as part of a randomized trial to reduce the effect of the many possible confounding factors.

Alteration of Transthyretin Microheterogeneity in Serum of Multiple Trauma Patients

Transthyretin (TTR) which exists in various isoforms, is a valid marker for acute phase response and subclinical malnutrition. The aim of the study was to investigate the relationship between inflammation, oxidative stress and the occurrence of changes in microheterogeneity of TTR.

A prospective, observational study at a level-I trauma center of a large urban medical university was performed. Patients were severely injured (n = 18; injury severity score (ISS): 34–66), and were observed within the first 24 hours of admittance and over the following days until day 20 after injury. 20 healthy subjects, matched by age and sex, were used as controls.

TTR was enriched by immunoprecipitation. Microheterogeneity of TTR was determined by linear matrix assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS). Four major mass signals were observed for TTR representing native, S-cysteinylated, S-cysteinglycinylated and S-glutathionylated TTR. In the course of their ICU stay, 14 of the 18 patients showed a transient change in microheterogeneity in favour of the S-cysteinglycinylated form of TTR (p < 0.05 vs. controls). The occurrence of this variant was not associated with the severity of trauma or the intensity of the acute-phase response, but was associated with oxidative stress as evidenced by Trolox.

Our results demonstrate that changes in microheterogeneity of TTR occur in a substantial number of ICU trauma patients. The diagnostic values of these changes remains to be elucidated. It is speculated that TTR modification may well be the mechanism underlying the morphological manifestation of amyloidose or Alzheimer's diseases in patients surviving multiple trauma.

It takes two to tango: Phagocyte and lymphocyte numbers in a small mammalian hibernator

Immunity is energetically costly and competes for resources with other physiological body functions, which may result in trade-offs that impair fitness during demanding situations. Endocrine mediators, particularly stress hormones, play a central role in these relationships and directly impact leukocyte differentials. To determine the effects of external stressors, energetic restraints and competing physiological functions on immune parameters and their relevance for fitness, we investigated leukocyte profiles during the active season of a small obligate hibernator, the edible dormouse (Glis glis), in five different study sites in south-western Germany. The highly synchronized yearly cycle of this species and the close adaptation of its life history to the irregular abundance of food resources provide a natural experiment to elucidate mechanisms underlying variations in fitness parameters. In contrast to previous studies on hibernators, that showed an immediate recovery of all leukocyte subtypes upon emergence, our study revealed that hibernation results in depleted phagocyte (neutrophils and monocytes) stores that recovered only slowly. As the phenomenon of low phagocyte counts was even more pronounced at the beginning of a low food year and primarily immature neutrophils were present in the blood upon emergence, preparatory mechanisms seem to determine the regeneration of phagocytes before hibernation is terminated. Surprisingly, the recovery of phagocytes thereafter took several weeks, presumably due to energetic restrictions. This impaired first line of defense coincides with lowest survival probabilities during the annual cycle of our study species. Reduced survival could furthermore be linked to drastic increases in the P/L ratio (phagocytes/lymphocytes), an indicator of physiological stress, during reproduction. On the other hand, moderate augmentations in the P/L ratio occurred during periods of low food availability and were associated with increased survival, but reproductive failure. In this case, the stress response probably represents an adaptive reaction that contributes to survival by activating energy resources. In contrast to our expectation, we could not detect an amplification of stress through high population densities. Summarized, results of our study clearly reveal that the leukocyte picture of active edible dormice responds sensitively to physiological conditions associated with hibernation, reproductive activity and food availability and can be linked to fitness parameters such as survival. Thus edible dormice represent an excellent model organism to investigate regulatory mechanisms of the immune system under natural conditions.

Protein requirements, morbidity and mortality in critically ill patients: fundamentals and applications

Recent evidence suggests that a negative protein balance secondary to severe disease is associated with increased morbidity. A loss of total body protein is inevitable in this scenario, even with an aggressive nutritional approach, primarily due to the catabolism of skeletal muscle fibers. The ubiquitin-proteasome system is the primary metabolic and biochemical mechanism involved in this process; paradoxically, this system consumes adenosine triphosphate as its energy source. It is possible that a neutral protein balance in these clinical situations is important for improving outcomes and achieving the caloric goals estimated or measured by indirect calorimetry. Recent studies have suggested that the use of higher protein concentrations in nutritional therapy for critically ill patients may help to reduce mortality. The purpose of this study was to review some of the nutrition therapy principles related to protein metabolism, evaluate the main assertions of the guidelines of specialty societies and review the recent studies that address these issues using critical insights from the authors' clinical experience.

Nutritional care of the obese adult burn patient: a U.K. Survey and literature review

Obesity is an emerging healthcare problem and affects an increasing number of burn patients worldwide. An email survey questionnaire was constructed and distributed among the 16 U.K. burn services providing adult inpatient facilities to investigate nutritional practices in obese thermally injured patients. Responses received from all dieticians invited to participate in the study were analyzed, and a relevant literature review of key aspects of nutritional care is presented. The majority of services believe that obese patients warrant a different nutritional approach with specific emphasis to avoid overfeeding. The most common algebraic formulae used to calculate calorific requirements include the Schofield, Henry, and modified Penn State equations. Indirect calorimetry despite being considered the "criterion standard" tool to calculate energy requirements is not currently used by any of the U.K. burn services. Gastric/enteral nutrition is initiated within 24 hours of admission in the services surveyed, and a variety of different practices were noted in terms of fasting protocols before procedures requiring general anesthesia/sedation. Hypocaloric regimens for obese patients are not supported by the majority of U.K. facilities, given the limited evidence base supporting their use. The results of this survey outline the wide diversity of dietetic practices adopted in the care of obese burn patients and reveal the need for further study to determine optimal nutritional strategies.

Tumors, IGF-2, and hypoglycemia: insights from the clinic, the laboratory, and the historical archive

Tumors of mesenchymal and epithelial origin produce IGF-2, which activates pathways in the tumors. In a minority of patients, the tumors (hepatomas, fibromas, and fibrosarcomas are the most common among many) release into the circulation enough IGF-2-related peptides to mimic the fasting hypoglycemia characteristic of patients with insulin-producing islet-cell tumors. Rarely, markedly elevated IGF-2 levels produce somatic changes suggestive of acromegaly. Typically, the elevated IGF-2 levels are associated with suppressed plasma levels of insulin, IGF-1, and GH. Complicating the pathophysiology are the IGF binding proteins (IGFBPs) that can bind IGF-2 and IGF-1, modifying hormone metabolism and action. IGFBP concentrations are often altered in the presence of these tumors. At the cellular level, the 3 hormone-related ligands, IGF-2, IGF-1, and insulin, all bind to 4 (or more) types of IGF-1 receptor (IGF-1R) and insulin receptor (IR). Each receptor has its own characteristic affinity for each ligand, a tyrosine kinase, and overlapping profiles of action in the target cells. The IGF-2R, in addition to binding mannose-6-phosphate-containing proteins, provides an IGF-2 degradation pathway. Recent evidence suggests IGF-2R involvement also in signal transduction. Surgery, the treatment of choice, can produce a cure. For patients not cured by surgery, multiple therapies exist, for the tumor and for hypoglycemia. Potential future therapeutic approaches are sketched. From 1910 to 1930, hypoglycemia, insulin, insulinomas, and non-islet-cell tumors were recognized. The latter third of the century witnessed the emergence of the immunoassay for insulin; the IGFs, their binding proteins, and assays to measure them; and receptors for the insulin-related peptides as well as the intracellular pathways beyond the receptor. In closing, we replace non-islet-cell tumor hypoglycemia, an outdated and misleading label, with IGF-2-oma, self-explanatory and consistent with names of other hormone-secreting tumors.

Perioperative nutritional support: immunonutrition, probiotics, and anabolic steroids

Nutritional support in surgical patients has evolved from simple provision of adequate calories to retard loss of lean body mass to the provision of specific nutrients in an attempt to manipulate metabolic and immune responses. Although still limited, the current understanding of this complex subject indicates that the type, route, amount, and composition of nutritional support provided to patients can affect their outcome. Further studies are, however, needed to better characterize the exact nutritional support that is most beneficial for a specific disease state and a specific patient.

IGF-1 and atherothrombosis: relevance to pathophysiology and therapy

IGF-1 (insulin-like growth factor-1) plays a unique role in the cell protection of multiple systems, where its fine-tuned signal transduction helps to preserve tissues from hypoxia, ischaemia and oxidative stress, thus mediating functional homoeostatic adjustments. In contrast, its deprivation results in apoptosis and dysfunction. Many prospective epidemiological surveys have associated low IGF-1 levels with late mortality, MI (myocardial infarction), HF (heart failure) and diabetes. Interventional studies suggest that IGF-1 has anti-atherogenic actions, owing to its multifaceted impact on cardiovascular risk factors and diseases. The metabolic ability of IGF-1 in coupling vasodilation with improved function plays a key role in these actions. The endothelial-protective, anti-platelet and anti-thrombotic activities of IGF-1 exert critical effects in preventing both vascular damage and mechanisms that lead to unstable coronary plaques and syndromes. The pro-survival and anti-inflammatory short-term properties of IGF-1 appear to reduce infarct size and improve LV (left ventricular) remodelling after MI. An immune-modulatory ability, which is able to suppress 'friendly fire' and autoreactivity, is a proposed important additional mechanism explaining the anti-thrombotic and anti-remodelling activities of IGF-1. The concern of cancer risk raised by long-term therapy with IGF-1, however, deserves further study. In the present review, we discuss the large body of published evidence and review data on rhIGF-1 (recombinant human IGF-1) administration in cardiovascular disease and diabetes, with a focus on dosage and safety issues. Perhaps the time has come for the regenerative properties of IGF-1 to be assessed as a new pharmacological tool in cardiovascular medicine.

Role of two nutritional hepatic markers (insulin-like growth factor 1 and transthyretin) in the clinical assessment and follow-up of acute intermittent porphyria patients

OBJECTIVE

Acute intermittent porphyria (AIP) is caused by a deficiency of hydroxymethylbilane synthase. Clinical manifestations are abdominal pain and neurovisceral symptoms, accompanied by overproduction of heme-precursors in the liver, which frequently remains long-lasting in AIP patients. We tested the hypothesis that this condition may be associated with alterations of hepatic proteins known to be either increased or decreased in serum according to diverse pathological conditions including malnutrition, inflammation or liver disease.

DESIGN

Serum proteins were analyzed in 26 biochemically active AIP patients that were classified according to the EPI (European Porphyria Initiative) guidelines as follows: (i) patients who presented a single acute attack having remained so far free of clinical symptoms; (ii) patients who present recurrent attacks or chronic symptoms associated with exacerbations of AIP.

RESULTS

Most of the serum proteins were within normal limits, however insulin-like growth factor 1 (IGF-1) was decreased in 53.8% of AIP patients (z-score = -2.86 +/- 0.37) and transthyretin (prealbumin) was found significantly decreased in 38.5% of them. The IGF-1 z-score was lower in group B versus group A patients (-2.66 vs. -1.43; P = 0.024). The coincident decrease of both IGF-1 and transthyretin was associated with worsening of the clinical condition.

CONCLUSIONS

This first study in humans suggests that the clinical expression AIP is associated with a state of under-nutrition and/or with hepatic inflammation due to the sustained accumulation of heme-precursors. We propose the use of both IGF-1 and transthyretin as biomarkers of disease morbidity/severity for the clinical follow-up of AIP patients.

Nutritional assessment: its role in the provision of nutritional support

Generalised undernutrition is common in hospital patients and in the community. It is frequently unrecognised and is associated with a range of adverse consequences that contribute to increased morbidity and mortality. The National Institute for Health and Clinical Excellence recommends that all individuals engaging with healthcare or admitted to residential homes in the community should be screened for undernutrition. Laboratory investigations have little place in the diagnosis of undernutrition: this is primarily a clinical process. In particular, the measurement of serum albumin concentration, though widely promulgated in the past as an index of nutritional status, is worthless for this purpose. Laboratory investigations are, however, of importance: to diagnose specific nutritional deficiencies (eg, of trace elements) and to monitor the provision of nutritional support, to detect metabolic complications and to assess its adequacy (for which the measurement of serum prealbumin concentrations, particularly in conjunction with measurements of C-reactive protein, may be of value).

Clinical indications for plasma protein assays: transthyretin (prealbumin) in inflammation and malnutrition

A large number of circumstances are associated with reduced serum concentrations of transthyretin (TTR), or prealbumin. The most common of these is the acute phase response, which may be due to inflammation, malignancy, trauma, or many other disorders. Some studies have shown a decrease in hospital stay with nutritional therapy based on TTR concentrations, but many recent studies have shown that concentrations of albumin, transferrin, and transthyretin correlate with severity of the underlying disease rather than with anthropometric indicators of hypo- or malnutrition. There are few if any conditions in which the concentration of this protein by itself is more helpful in diagnosis, prognosis, or follow up than are other clinical findings. In the majority of cases, the serum concentration of C-reactive protein is adequate for detection and monitoring of acute phase responses and for prognosis. Although over diagnosis and treatment of presumed protein energy malnutrition is probably not detrimental to most patients, the failure to detect other causes of decreased concentrations (such as serious bacterial infections or malignancy) of the so-called visceral or hepatic proteins could possibly result in increased morbidity or even mortality. In addition to these caveats, assays for TTR have a relatively high level of uncertainty ("imprecision"). Clinical evaluation--history and physical examination--should remain the mainstay of nutritional assessment.

Number and proliferative capacity of human mesenchymal stem cells are modulated positively in multiple trauma patients and negatively in atrophic nonunions

Mesenchymal stem cells (MSCs) participate in regenerative osteogenesis by generating bone-forming cells. To examine the proliferative capacity of MSC populations from bone marrow and their relationship to trauma severity (multiple trauma, monofracture, atrophic nonunion), we quantified colony properties of human MSCs in vitro. Serum levels of mediators associated with bone formation were also assessed. Fifty-five individuals were enrolled in this study (13 multiple trauma patients, 15 patients with monofracture, 20 patients with atrophic nonunions, 7 healthy volunteers). The colony forming unit-fibroblast (CFU-F) assay was used to quantify total colony number, mean cell density per colony, and mean colony area. MSC phenotype was established using flow cytometry and osteogenic differentiation. MSCs obtained from multiple-trauma patients yielded the highest reservoir. Significant differences in colony numbers of MSCs in female subjects were found between multiple-trauma patients (mean +/- SD 48 +/- 21 CFU-F/culture) and healthy volunteers (18.7 +/- 3.3 CFU-F/culture, P < 0.05), patients with monotrauma (15 +/- 10 CFU-F/culture, P < 0.05), and patients with atrophic nonunions (6.3 +/- 4.1 CFU-F/culture, P < 0.05). In male participants, significant differences were found between patients with nonunions (14 +/- 14 CFU-F/culture) and healthy volunteers (54 +/- 17 CFU-F/culture, P < 0.05) as well as multiple-trauma patients (59 +/- 25 CFU-F/culture, P < 0.05). The highest proliferative capacity (cell density) was seen in multiple-trauma patients. These data suggest that trauma severity and gender affect the reservoir and proliferation capacity of bone marrow-derived MSCs.

Nutritional gain versus financial gain: The role of metabolic carts in the surgical ICU

BACKGROUND

Adequate nutritional replacement of critically ill and injured patients is of paramount importance, as it decreases infectious morbidity and mortality. However, multiple methods of determining nutritional requirements exist, including mathematical formulas, weight based calculations, and the use of metabolic cart measurements, the latter of which is associated with significant labor and equipment costs. We hypothesized that metabolic cart measurements, despite increasing the cost of care, would more accurately determine nutritional requirements in a critically ill population than formulaic or weight-based calculations.

METHODS

Consecutive metabolic cart measurements were prospectively obtained on 59 critically ill surgery and trauma patients, and compared with predicted values as determined by the Harris-Benedict equation and weight-based calculations. Comparison was made to actual resting energy expenditure data acquired via indirect calorimetry data obtained from serial metabolic carts.

RESULTS

There were 59 patients who formed the study population, with 37% of the population having two or more metabolic cart readings (total number of cart readings was 106). There was no statistically significant difference between the metabolic cart results, the predicted resting energy expenditure as calculated by the Harris-Benedict equation adjusted with a factor of 1.5, and a weight based calculation at 30 kcal/kg adjusted body weight. Metabolic requirements were stable over time (4-48 days) without significant variation. Nutritional parameters, as evaluated by the visceral proteins prealbumin and transferrin significantly increased with time in injured patients.

CONCLUSIONS

Either 30 kcal/kg adjusted body weight or the resting energy expenditure calculated from the Harris-Benedict equation multiplied by 1.5 adequately predicts the nutritional requirements of critically ill surgery and trauma patients. The addition of metabolic cart data does not provide any additional information in the determination of caloric needs in the critically ill and injured patient. In this population, omission of metabolic cart data would have saved 33,000 dollars without adversely affecting patient outcome.

Prealbumin serum concentrations as a useful tool in the assessment of malnutrition in hospitalized patients

BACKGROUND

Protein-energy malnutrition (PEM) is a common condition among patients admitted to hospitals, and it is associated with a worse prognosis and increased mortality. Although several screening systems have been developed, PEM is still poorly recognized, and there is no consensus on which test is more reliable and feasible in clinical practice. Prealbumin (PAB) is a potential useful PEM marker because its serum concentrations are closely related to early changes in nutritional status.

METHODS

We studied PEM prevalence and PAB serum concentrations in 108 hospitalized patients. The Detailed Nutritional Assessment (DNA) was used as the reference method to determine PEM. PAB performance was compared with that of 2 other methods, the Subjective Global Assessment (SGA) and the Prognostic Inflammatory and Nutritional Index score (PINI).

RESULTS

According to the DNA reference method, 41% of patients were classified with mild malnutrition and 19% with severe malnutrition. PAB showed the best concordance with the standard DNA method (concordance index, 76.8%) and a good sensitivity/specificity profile (83.1%/76.7%) compared with SGA and PINI.

CONCLUSIONS

We conclude that PAB could represent a feasible and reliable tool in the evaluation of malnutrition, especially in settings where it is difficult to obtain a more detailed and comprehensive nutritional assessment such as the DNA.

Surrogate nutrition markers, malnutrition, and adequacy of nutrition support

Surrogate nutrition markers are used to assess adequacy of nourishment and to define malnutrition despite evidence that fails to link nourishment, surrogate markers, and outcomes. Markers such as serum levels of albumin, prealbumin, transferrin, and IGF-1 and delayed hypersensitivity and total lymphocyte count may be valid to help stratify risk. However, it is not appropriate to consider these as markers of adequacy of nourishment in the sick patient.

The impact of parenteral nutrition on the body composition of patients with acute pancreatitis

BACKGROUND

Nutrition support by the enteral route is now the preferred modality in patients with severe acute pancreatitis. Parenteral nutrition is now required to supplement enteral nutrition when the latter is not able to provide the full nutritional requirement. We report the changes in body composition, plasma proteins, and resting energy expenditure (REE) during 14 days of parenteral nutrition (PN) in patients with acute pancreatitis.

METHODS

Total body protein (TBP), total body water (TBW), and total body fat (TBF) were measured by neutron activation analysis and tritium dilution before and after PN. Fat-free mass (FFM) was derived as the difference between body weight and TBF. REE was measured by indirect calorimetry. Protein index (PI) was the ratio of measured TBP to TBP, calculated from healthy volunteers.

RESULTS

Fifteen patients with acute pancreatitis (11 men, 4 women; median age 56, range 30-80 years) were studied. Thirteen patients had severe acute pancreatitis (Atlanta criteria), and 1 patient died. The gains in body weight (1.05 +/- 0.77 kg), TBW (0.49 +/- 0.87 kg), TBP (0.20 +/- 0.22 kg), FFM (0.73 +/- 0.92 kg), TBF (0.32 +/- 0.95 kg), and REE (146 +/- 90 kcal/d) after 14 days of PN were not significant. Plasma prealbumin increased by 46.5% (p = .020). When patients (n = 6) with intercurrent sepsis and recent surgery were excluded, there were significant increases in TBP (0.65 +/- 0.17 kg, p = .005) and PI (0.060 +/- 0.011, p = .0006).

CONCLUSIONS

Body composition is preserved in acute pancreatitis during 14 days of PN. In patients without sepsis or recent surgery, PN is able to significantly increase body protein stores.

Hepatic proteins and nutrition assessment

Serum hepatic protein (albumin, transferrin, and prealbumin) levels have historically been linked in clinical practice to nutritional status. This paradigm can be traced to two conventional categories of malnutrition: kwashiorkor and marasmus. Explanations for both of these conditions evolved before knowledge of the inflammatory processes of acute and chronic illness were known. Substantial literature on the inflammatory process and its effects on hepatic protein metabolism has replaced previous reports suggesting that nutritional status and protein intake are the significant correlates with serum hepatic protein levels. Compelling evidence suggests that serum hepatic protein levels correlate with morbidity and mortality. Thus, serum hepatic protein levels are useful indicators of severity of illness. They help identify those who are the most likely to develop malnutrition, even if well nourished prior to trauma or the onset of illness. Furthermore, hepatic protein levels do not accurately measure nutritional repletion. Low serum levels indicate that a patient is very ill and probably requires aggressive and closely monitored medical nutrition therapy.

The role of visceral proteins in the nutritional assessment of intensive care unit patients

PURPOSE OF REVIEW

This review analyses the recently published literature focusing on nutritional assessment in intensive care unit patients. The metabolic response to nutritional intervention is difficult to evaluate in critically ill patients whose body weight is influenced largely by massive fluid administration or losses. Visceral protein plasma levels have been proposed for this purpose, because they reflect hepatic synthesis in response to nutrient supply. However, in acute inflammatory states, liver activity is converted to the synthesis of acute-phase response proteins, resulting in a dramatic drop in visceral proteins, despite nutritional support.

RECENT FINDINGS

The data regarding visceral protein levels were examined in relation to nutritional supplementation, and compared with other nutritional parameters and clinical outcomes. Transthyretin and retinol-binding protein levels seem to be the most sensitive to nutritional intervention. They are also the earliest to rise at the decrease of acute-phase protein levels, therefore representing a good index of the reversing reprioritization of hepatic protein synthesis. An inconsistent relationship was found between visceral protein plasma levels and clinical outcome in intensive care unit patients, probably because of the difficulty in demonstrating clearly a beneficial effect of nutritional supplementation in highly catabolic conditions.

SUMMARY

In the acute stage of critical illness, the bi-weekly measurement of transthyretin together with acute-phase response protein plasma levels seems to be a 'window' on the metabolic condition (anabolism versus catabolism). However, only in the presence of stable inflammatory parameters do transthyretin levels reflect the adequacy of nutritional coverage.

Exercise, diet, and childhood obesity: the GH-IGF-I connection

The recent "obesity epidemic" among children and adolescents is a major public health concern. The mechanisms responsible for the increased incidence of childhood obesity are not yet well understood. The absence of a clear mechanism makes treating the obese child or adolescent a difficult task, and standardized therapeutic approaches simply do not yet exist. Metabolic derangements associated with obesity may contribute to the difficulty in treatment. Observed abnormalities in the growth hormone (GH)-insulin-like growth factor-I (IGF-I) axis in obese adults and the impact of exercise on the GH-IGF-I system are of particular relevance to the growing obese child. In this review, we focus on the interacting mechanisms of diet and exercise through specific hormonal mediators and their contribution to the current obesity epidemic. An improved understanding of these mechanisms may be helpful in creating effective treatment programs for children with obesity.

Growth hormone/insulin-like growth factors axis in children undergoing cardiac surgery

OBJECTIVES

To describe the sequential changes in the growth hormone (GH)/insulin-like growth factors axis and their relationship with nitrogen balance in children following cardiac surgery.

DESIGN

Prospective, descriptive study.

SETTING

Pediatric intensive care unit of a university hospital.

PATIENTS

Twenty three postoperative cardiac surgical patients after bypass.

INTERVENTIONS

Blood and urine samples were taken on days 1, 2, and 7 of pediatric intensive care unit admission. An intraanesthesia, presurgery sample was also obtained.

MEASUREMENTS AND MAIN RESULTS

Serum concentrations of insulin, insulin growth factor-I (IGF-I), insulin growth factor binding proteins 1 and 3 (IGFBP-1 and IGFBP-3), growth hormone binding protein (GHBP), and urinary concentrations of GH and free cortisol (UFC) were measured on days 1, 2, and 7 of the study period. C-reactive protein and prealbumin, were also measured in blood samples as conventional markers of inflammatory or nutritional status. Pediatric Risk of Mortality II score and UFC were used as indicators of acute stress. The nitrogen balance and urinary nitrogen urea excretion were used as markers of catabolic state. Urinary concentrations of GH were high from days 1 to 7. Plasma concentrations of IGF-I and GHBP were low and remained low throughout the study period. IGFBP-3 levels were below normal but without reaching statistical significance. The IGFBP-1 levels were initially high but descended progressively toward normal values. Urinary nitrogen urea production was persistently elevated and was associated with a negative nitrogen balance. No relationship was found between nitrogen balance and IGF-I, prealbumin, or C-reactive protein.

CONCLUSIONS

A GH-resistant state is observed in postoperative children following cardiac surgery. Stress response is characterized by an elevation of growth hormone secretion that is not followed by the corresponding increment in IGF-I and IGFBP-3 concentrations. These hormonal changes may be permissive for the catabolic state of these patients. IGF-I and IGFBP-1 and -3 are not related to either nitrogen balance or urinary nitrogen urea excretion.

Fitness, training, and the growth hormone-->insulin-like growth factor I axis in prepubertal girls

We recently demonstrated that a brief endurance type training program led to increases in thigh muscle mass and peak oxygen uptake (VO(2)) in prepubertal girls. In this study, we examined the effect of training on the GH-->insulin-like growth factor I (GH-->IGF-I) axis, a system known to be involved both in the process of growth and development and in the response to exercise. Healthy girls (mean age 9.17 +/- 0.10 yr old) volunteered for the study and were randomized to control (n = 20) and training groups (n = 19) for 5 weeks. Peak VO(2), thigh muscle volume, and blood samples [for IGF-I, IGF-binding proteins (IGFBP)-1 to -6, and GHBP] were measured. At baseline, IGF-I was significantly correlated with both peak VO(2) (r = 0.44, P < 0.02) and muscle volume (r = 0.58, P < 0.004). IGFBP-1 was negatively correlated with muscle volume (r = -0.71, P < 0.0001), as was IGFBP-2. IGFBP-4 and -5 were significantly correlated with muscle volume. We found a threshold value of body mass index percentile (by age) of about 71, above which systematic changes in GHBP, IGFBP-1, and peak VO(2) per kilogram were noted, suggesting decreases in the following: 1) GH function, 2) insulin sensitivity, and 3) fitness. Following the training intervention, IGF-I increased in control (19.4 +/- 9.6%, P < 0.05) but not trained subjects, and both IGFBP-3 and GHBP decreased in the training group (-4.2 +/- 3.1% and -9.9 +/- 3.8%, respectively, P < 0.05). Fitness in prepubertal girls is associated with an activated GH-->IGF-I axis, but, paradoxically, early in a training program, children first pass through what appears to be a neuroendocrine state more consistent with catabolism.

Serum leptin levels are higher but are not independently associated with severity or mortality in the multiple organ dysfunction/systemic inflammatory response syndrome: a matched case control and a longitudinal study

OBJECTIVE

Hypercatabolism and immune dysfunction are closely associated with the development of systemic inflammatory response--multiple organ dysfunction (SIRS/MODS) in critical illness. It remains unclear however, whether leptin, an adipocyte-derived hormone whose levels are influenced by several cytokines and which regulates immune function, food-intake and energy expenditure is independently related to the development of and/or severity and mortality from SIRS/MODS.

DESIGN AND PATIENTS

To assess the role of leptin in SIRS/MODS we performed a matched case control and a longitudinal study (14 days) in 35 critically ill patients with SIRS/MODS and 35 matched controls.

RESULTS

Baseline leptin levels were positively associated with body mass index (BMI) and TNF-alpha (P < 0.01) in patients and with IGF-1 and IL-6 levels (P < 0.05) in controls. Furthermore, leptin levels exhibited a progressive increase from the first to the last day of the study and although baseline levels were not different, peak leptin levels as well as leptin levels on the last day of the study were significantly higher in cases than in controls (P < 0.05). TNF-alpha levels, IL-6 and cortisol levels were also higher, whereas IGF-1 levels were lower in cases (P < 0.05). To assess whether leptin levels are independently associated with SIRS/MODS we performed multivariate logistic regression analysis which revealed that leptin up-regulation in cases is mediated by elevated TNF-alpha and cortisol levels. Finally, there was no independent association between leptin and survival in this group of critically ill patients.

CONCLUSION

We conclude that cytokines and cortisol upregulate leptin levels, which may contribute to the development of the hypercatabolism, wasting and immune dysfunction but leptin levels are not independently associated with severity or mortality of patients with systemic inflammatory response-multiple organ dysfunction.

Effect of exercise on cytokines and growth mediators in prepubertal children

Many of the anabolic effects of exercise are mediated through insulin-like growth factor-I (IGF-I), but in adolescents, brief exercise training leads to reductions, rather than the expected increase, in circulating IGF-I. Certain cytokines--interleukin-(IL) 1beta (IL-1beta), IL-6 (IL-6), and tumor necrosis factor-alpha--are increased by exercise in adults and are known to inhibit IGF-I. To test the hypothesis that these cytokines might play a role in the adaptation to exercise, we measured the acute effects of exercise on selected cytokines and growth factors in 17 healthy 8- to 11-y-old children (4 females). Designed to mimic patterns and intensity of exercise found in the real lives of American children, the exercise protocol consisted of a 1.5-h soccer practice (of which about 40 min constituted of vigorous exercise). Pre- and postexercise urine and saliva samples were obtained in all subjects and both blood and urine in nine subjects. The exercise led to significant increases in circulating tumor necrosis factor-alpha (18 +/- 7%, p < 0.05) and IL-6 (125 +/- 35%, p < 0.01) as well as a significant increase in the antiinflammatory cytokine IL-1 receptor antagonist (33 +/- 10%, p < 0.01). Urine levels of IL-6 were also substantially increased by exercise (440 +/- 137%, p < 0.0001). Circulating levels of IGF-I were reduced to a small but significant degree (-6.4 +/- 3.2%, p < 0.05), although IGF-binding protein-1 (known to inhibit IGF-I) was substantially increased (156 +/- 40%, p < 0.001). Cytokines are systemically increased after relatively brief exercise in healthy children. This increase may alter critical anabolic agents such as IGF-I and its binding proteins.

Controlled study of early postoperative parenteral nutrition in children

BACKGROUND/PURPOSE

Nutritional support of surgical patients has improved in recent years because of the possibility of modulating catabolism and anabolism, thus enhancing the immune response and repair processes. The objective of this study was to evaluate metabolic effects of early parenteral nutrition (PN) after major surgery.

METHODS

The authors studied 63 children aged 4 to 14 years with diffuse peritonitis caused by perforated-suppurative appendicitis. They were assigned randomly to a study group (SG, n = 31), which received PN for 5 days, starting 24 to 48 hours after surgery or to a control group (CG, n = 32), that received standard treatment (fluids). Weight, C-reactive protein (CRP), albumin, prealbumin, glycemia, nitrogen balance (NB), and insulinlike growth factor (IGF-I), were evaluated on postoperative days 1, 4, and 6.

RESULTS

Early nutritional support was associated with a significant improvement in NB and IGF-I (Repeat measures analysis of variance IGF-I, P<.001 and NB P<.01).

CONCLUSIONS

The authors conclude that early parenteral nutrition has a positive effect on the anabolic response as shown by improved NB and higher IGF-I levels in pediatric patients after major surgery.

Nutritional, respiratory, and psychological effects of recombinant human growth hormone in patients undergoing abdominal aortic aneurysm repair

BACKGROUND

Recombinant human growth hormone (rhGH) has been shown to have powerful anabolic effects and to reduce or even prevent nitrogen catabolism in stressed patients. The effects of rhGH on functional parameters are less clearly defined. The aim of this study was to assess the effects of perioperative rhGH on nutritional markers, skeletal muscle function, and psychological well-being in patients undergoing infrarenal, abdominal aortic aneurysm repair.

METHODS

Thirty-three patients undergoing elective infrarenal abdominal aortic aneurysm repair were randomized to one of three groups: (1) control (n = 12): placebo for 6 days before and after surgery; (2) preop + postop (n = 10): rhGH (Genotropin; Pharmacia Ltd, Uppsala, Sweden) 0.3 IU/kg/d for 6 days before and after surgery; and (3) postop (n = 11): placebo for 6 days before and rhGH 0.3 IU/kg/d for 6 days after surgery. Patients were assessed on days -7 and -1 before surgery and days 7, 14, and 60 after surgery.

RESULTS

Administration of rhGH resulted in increased insulin-like growth factor 1 levels, the increase being significantly more marked in the group given rhGH preoperatively. Preoperative and postoperative rhGH reduced the postoperative decrease in both serum transferrin and grip strength at day 7 by 30% and 70%, respectively. Postoperative respiratory function and arterial oxygenation also were improved, with significant differences in arterial oxygenation between rhGH-treated and untreated groups. No difference in mood was seen between groups after surgery, nor was there any difference between subjective assessment of fatigue scores between groups.

CONCLUSIONS

This pilot study indicates that rhGH administered preoperatively has beneficial effects on skeletal muscle and respiratory function and may be more useful than postoperative rhGH administration alone.

Insulin-like growth factor-1 (IGF-1) and growth hormone (GH) in immunity and inflammation

In recent years many efforts have been undertaken to elucidate the complex interactions between mediators of the endocrine system and the immune system. The main effector of growth hormone (GH) is insulin-like growth factor-1 (IGF-1), an endocrine mediator of growth and development under physiological conditions. Besides this important function, IGF-1 also plays a prominent role in the regulation of immunity and inflammation. This article will address the involvement of IGF-1 in innate as well as acquired immunity and host-defense. We also discuss the role of IGF-1 in the course of inflammatory disorders, including sepsis and sepsis-induced catabolism as well as degenerative arthritis. Based on recent insights, we finally examine the pathophysiological background, potential pitfalls and perspectives of IGF-1 suppletion therapy in these conditions.

Nutrition support in patients with multiple organ failure

The problem with any attempt to feed patients in multiple organ failure is that, because of an ongoing inflammatory process, the conventional techniques of supplying energy and protein do not maintain lean tissue mass. In addition, the conventional markers of nutritional status, both anthropometric (body mass and composition, arm circumference, etc.) and visceral protein (albumin, prealbumin) as well as immunological markers (delayed reactive skin hypersenstivity to common antigens and lymphocyte counts) are confounded by fluid retention (5-15 l) and the metabolic response to the illness. Recent research has focussed on the nature and origin of this inflammatory response, the problems of trying to feed an individual undergoing such a response, the details of the protein breakdown observed in sepsis and multiple organ failure and methods of modifying the response favourably.

Postoperative nutrition in surgery for major trauma

Research in the area of the nutritional support of trauma patients has continued to focus on a few main areas: the effect that the route, timing and type of feeding has on patient outcome, nutritional assessment and mucosal immunity. This year a nutritional conference has released a paper, summarizing the current state of research in this area, that generated some controversy.