Nutritional and metabolic support in patients undergoing bone marrow transplantation

Bone marrow transplantation (BMT) is a sophisticated procedure consisting of the administration of high-dose chemoradiotherapy followed by intravenous infusion of hemopoietic stem cells to reestablish marrow function when bone marrow is damaged or defective. BMT is used in the treatment of solid tumors, hematologic diseases, and autoimmune disorders. Artificial nutrition, total parenteral nutrition in particular, is provided to patients undergoing BMT to minimize the nutritional consequences of both the conditioning regimens (eg, mucositis of the gastrointestinal tract) and complications resulting from the procedure (eg, graft versus host disease and venoocclusive disease of the liver). Although artificial nutrition is now recognized as the standard of care for BMT patients, defined guidelines for the use of artificial nutrition in this clinical setting are lacking. During the past 2 decades, artificial nutrition in BMT patients has moved from simple supportive care to adjunctive therapy because of the possible benefits, not strictly nutritional, of specialized nutritional intervention. Although data exist documenting the beneficial role of special nutrients, such as lipids and glutamine, in the management of BMT recipients, the results obtained to date are controversial. The reasons for this controversy may reside in the heterogeneity of the patients studied and of the study designs. This review focuses on the need to correctly identify the different patterns of BMT to achieve reproducible and reliable data, which may in turn be used to devise precise guidelines for the use of specialized artificial nutrition in BMT patients.

Idiopathic AL amyloidosis and biclonal paraproteinemia: a case report and review of the literature

A case of 79 year-old man suffering from nephrotic syndrome, infiltrative cardiomyopathy and sensitive neuropathy of the lower limbs, associated with biclonal gammopathy (IgG K and IgA A), is described. There was a history of non-insulin dependent diabetes mellitus and of two lung nodules considered as benign lesions on the basis of cytologic, hematologic and instrumental examination. A rectal biopsy positive for amyloid deposition (Congo red histology and immunofluorescence study) led to the diagnosis of AL amyloidosis. Considering that the patient did not fulfill diagnostic criteria for lymphoproliferative diaseases (myeloma, lymphoma or Waldenström's macroglubulinemia), nor for secondary malignant paraproteinemia, a diagnosis of idiopathic AL amyloidosis with biclonal gammopathy was made. Very few cases of idiopathic AL amyloidosis with double component are reported in the literature. Our review suggests that idiopathic AL amyloidosis with biclonal gammopathy is similar to idiopathic AL amyloidosis with monoclonal paraproteinemia in terms of clinical features, response to therapy and prognosis. Further studies, however, are necessary to clarify the true incidence and the clinical features of idopathic AL amyloidosis associated with biclonal gammopathy.

Impaired nutritional status in common variable immunodeficiency patients correlates with reduced levels of serum IgA and of circulating CD4+ T lymphocytes

BACKGROUND

Common variable immunodeficiency (CVI) is a primary defect of the immune system. Infections, persistent diarrhoea and malabsorption may result in malnutrition, which may in turn contribute to increased morbidity. In this paper, the prevalence of malnutrition in CVI was evaluated.

PATIENTS AND METHODS

Forty CVI patients (20 male, 20 female, aged 17-75 years) underwent anthropometric measurements from which body mass index, arm fat and muscle area were calculated. Body mass index values < 18.5 and arm fat and muscle area values < 10th percentile were considered indicative of malnutrition. Patients were divided into four groups according to circulating CD4+ T cells (lower or greater than 300 microL(-1)) and serum immunoglobulin A (IgA) levels (detectable and undetectable).

RESULTS

Body mass index < 18.5, arm fat and muscle area < 10th percentile were observed in 23%, 58% and 44%, respectively, of patients. Lower values of body mass index, arm fat and muscle area were more frequent in patients with low CD4+ cells and undetectable IgA. Low arm fat values were more frequent in patients with diarrhoea (P = 0.03). Infectious episodes were more frequent in undetectable IgA than in detectable IgA patients (P = 0.04).

CONCLUSIONS

Anthropometric measurements revealed an increased rate of malnutrition in CVI patients, particularly in those with low CD4+ and undetectable IgA, suggesting that selected CVI subjects could be considered for standard or specialized nutritional support.

Increased muscle ubiquitin mRNA levels in gastric cancer patients

The intramuscular ATP-dependent ubiquitin (Ub)-proteasome proteolytic system is hyperactivated in experimental cancer cachexia. The present study aimed at verifying whether the expression of the muscle Ub mRNA is altered in patients with cancer. Total muscle RNA was extracted using the guanidinium isothiocyanate/phenol/chloroform method from rectus abdominis biopsies obtained intraoperatively from 20 gastric cancer (GC) patients and 10 subjects with benign abdominal diseases (CON) undergoing surgery. Ub mRNA levels were measured by northern blot analysis. Serum soluble tumor necrosis factor receptor (sTNFR) was measured by ELISA. Ub mRNA levels (arbitrary units, means +/- SD) were 2,345 +/- 195 in GC and 1,162 +/- 132 in CON (P = 0.0005). Ub mRNA levels directly correlated with disease stage (r = 0.608, P = 0.005), being 1,945 +/- 786 in stages I and II, 2,480 +/- 650 in stage III, and 3,799 +/- 66 in stage IV. Ub mRNA and sTNFR did not correlate with age and nutritional parameters. This study confirms experimental data indicating an overexpression of muscle Ub mRNA in cancer cachexia. Lack of correlation with nutritional status suggests that Ub activation in human cancer is an early feature that precedes any clinical sign of cachexia.

Serum tumour necrosis factor-alpha levels in cancer patients are discontinuous and correlate with weight loss

BACKGROUND

Tumour necrosis factor-alpha (TNF) has been regarded as a potential mediator of cancer cachexia. Assessment of TNF circulating levels in cancer patients and their correlation with weight loss has led to controversial results.

MATERIALS AND METHODS

We measured TNF circulating levels in 28 patients with gastrointestinal cancer and 29 controls with benign gastrointestinal diseases at different times (08.00 h, 14.00 h, 20.00 h) before operation.

RESULTS

TNF activity was not detected in any of controls at any times. In cancer patients, TNF circulating levels were detectable in 18 cases (64.3%) and appeared to be discontinuous. TNF levels above the limit of detection were present in 15 patients (53.6%) at 08.00 h, in 14 (50%) at 014.00 h and in nine (32.1%) at 20.00 h. Mean TNF levels were 14.3 +/- 4 pg mL(-1) at 08.00 h, 16.7 +/- 4.6 pg mL(-1) at 14.00 h (P = 0.05) and 18.5 +/- 10.2 pg mL(-1) at 20.00 h (P < 0.05 vs. 08.00 h and 14.00 h). According to Spearman's analysis, the sum of TNF concentrations at the three times significantly correlated with the severity of weight loss (Spearman's correlation coefficient = - 0.420; P = 0.026). TNF concentrations were consistently and significantly higher in patients with severe weight loss than in those with moderate or light weight loss at 08.00 h (26.3 +/- 8.3, 8.9 +/- 4.2, 3.8 +/- 2.1, respectively; P = 0.04 at one-way ANOVA). TNF levels were higher in anorectic than in nonanorectic patients at any hour, but the differences were not statistically significant.

CONCLUSIONS

The present study demonstrates that TNF is intermittently or discontinuously detectable in patients with gastrointestinal cancer and that its levels correlate with the severity of weight loss.

[Pathogenetic and therapeutic aspects of secondary anorexia]

Anorexia is an often underrated symptom in the clinical management of patients suffering from chronic diseases. Moreover, the anorexia accompanying chronic diseases (secondary anorexia) is often confused with anorexia nervosa, a typically neuropsychiatric disorder involving completely different pathogenic mechanisms and therapeutic strategies. Secondary anorexia is one of the main factors responsible for the development of malnutrition, which in turn negatively affects patient morbidity and mortality. Different mechanisms have been proposed to explain the pathogenesis of secondary anorexia. However, consistent experimental and clinical evidence seems to point to hypothalamic serotonergic system hyperactivity as a preeminent cause; this hyperactivity appears to be triggered by enhanced brain availability of tryptophan, the aminoacid precursor of serotonin. The hyperactive hypothalamic serotonergic system might also represent the final effector where different regulatory and modulating pathways, including cytokines, converge. The involvement of tryptophan and the hypothalamic serotonergic system is further supported by the effectiveness of a therapeutic strategy, based on the inhibition of tryptophan entry into the brain, in increasing the food intake of anorectic patients. Although these results represent an encouraging approach to the treatment of secondary anorexia, with possible beneficial effects on the nutritional status of patients, they need to be validated in larger trials.

Peripherally injected IL-1 induces anorexia and increases brain tryptophan concentrations

Interleukin-1 is an anorexigenic cytokine, and is involved in the pathogenesis of cancer anorexia. Interleukin-1 induced anorexia is mediated by direct action within the hypothalamus, and by peripheral mechanism(s) yet to be determined. Here we present evidence showing that in an animal model the peripheral injection of interleukin-1 is followed by a significant rise in brain tryptophan concentrations. Tryptophan is the precursor of the neurotransmitter serotonin, known to mediate the onset of satiety under normal and pathological conditions. By inference, we conclude that interleukin-1 induced anorexia is mediated by at least two different mechanism: i) interleukin-1 direct action within the hypothalamus; ii) increased brain serotonergic activity, secondary to interleukin-1 induced increased brain availability of the serotonin precursor, tryptophan.

Effect of cisplatin and paclitaxel on plasma free tryptophan levels. An in vitro study

Emesis is a common side effect of some antineoplastic drugs. Cisplatin (CP) induces a biphasic pattern of emesis referred to as acute (AE) and delayed (DE) emesis. The serotonergic system plays a major role in the pathogenesis of CP-induced AE, as suggested by the therapeutic efficacy of 5HT3 receptor antagonists. The pathogenesis of CP-induced DE are not clear. To date, there are no pharmacological agents which satisfactorily control DE. We hypothesize that increased availability of tryptophan (TRP) for the synthesis of brain serotonin (5-HT) could, at least in part, contribute to CP-induced DE. In fact, within 2-4 hrs of administration, CP is largely bound to albumin (ALB) with consequent possible displacement of TRP which circulates in plasma mostly (90% of total plasma TRP) bound to its natural carrier, ALB. To test this hypothesis, we studied in vitro the effect of increasing doses of cisplatin on F-TRP in plasma obtained from healthy volunteers. We also tested the effects of therapeutic amounts of paclitaxel, an antineoplastc agent which does not cause emesis.

RESULTS

F-TRP concentrations increased in a dose-dependent manner following incubation with cisplatin, in contrast to paclitaxel (PTX).

CONCLUSIONS

The preliminary data obtained suggest that CP, but not PTX, at therapeutic doses, increases plasma F-TRP concentrations. This increase has likely negligible relevance in CP-induced AE, which is induced by the 5-HT released by the enterochromaffin cell system, while it might play a role in the pathogenesis of CP-induced DE. In fact, CP binding to ALB is stable for 4-5 days following administration, thus suggesting long-term TRP displacement from ALB and enhanced brain 5-HT synthesis and release. Whether increased TRP availability for 5-HT synthesis might be the pathogenic mechanism for CP-induced DE in vivo, is currently being tested.

VMN hypothalamic dopamine and serotonin in anorectic septic rats

During sepsis, catabolism of proteins and associated changes in plasma amino acids occur. Tryptophan and tyrosine, and their derivatives serotonin (5-HT) and dopamine (DA), influence hypothalamic feeding-related areas and are associated with the onset of anorexia. We hypothesized that anorexia of sepsis is associated with changes in serotonin and dopamine in the ventromedial nucleus (VMN) of the hypothalamus. The aim of this study was to test our hypothesis by measuring intra-VMN changes of these two neurotransmitters at the onset of anorexia during sepsis. Fischer 344 male rats had an intracerebral guide cannula stereotaxically implanted into the VMN. Ten days later, in awake, overnight-food-deprived rats, a microdialysis probe was inserted through the in situ VMN cannula. Two hours thereafter, serial baseline serotonin and dopamine concentrations were measured. Then cecal ligation and puncture to induce sepsis or a control laparotomy was performed under isoflurane anesthesia. VMN microdialysis samples were serially collected every 30 min for 8 h after the surgical procedure to determine 5-HT and DA changes in response to sepsis. During the hypermetabolic response to sepsis, a strong association occurred between anorexia and a significant reduction of VMN dopamine concentration (P < 0.05; constant rate of dopamine decrease in the Study group of 0.99 pg per 2 h); no changes occurred in 5-HT in association with anorexia of sepsis. Six hours after operation, a single meal was offered for 20 min to assess the response of neurotransmitters to food ingestion. Food intake was minimal in anorectic septic rats (mean size of the after food-deprived meal in the Septic group was 0.03+/-0.01 g, that of the Control group was 1.27+/-0.14 g; P = 0.0001), while Control rats demonstrated anticipated changes in neurotransmitters in response to eating. We conclude that the onset of anorexia in septic rats is associated with a reduction in VMN dopamine.

Albumin synthesis is diminished in men consuming a predominantly vegetarian diet

Albumin synthesis was calculated in healthy male volunteers consuming diets differing in the relative contribution of protein from animal or vegetable sources. In one study (Study 1, n = 4) two isoenergetic and isonitrogenous diets were consumed for a period of 10 d each. One diet (diet A) was animal protein rich (74%), the other one (diet V) contained 67% of vegetable protein. Albumin synthesis rate was measured from L-[(2)H(5)]phenylalanine incorporation (43 mg/kg) at the end of each dietary period. Both albumin fractional synthesis rate (FSR) (5.7 +/- 0.6 vs. 6.7 +/- 0. 8%/d, P = 0.04) and absolute synthesis rate (ASR) (123 +/- 6 vs. 143 +/- 8 mg. kg(-1). d(-1), P = 0.05) were reduced after diet V. In a second study (Study 2, n = 8) a third dietary treatment was added (Diet VS). This was similar to diet V but supplemented with soy protein (18g/d). The results of study 2 confirmed that albumin synthesis was reduced after diet V (FSR: 5.9 +/- 0.3 vs. 6.7 +/- 0. 5%/d, P = 0.015; ASR: 126 +/- 7 vs. 146 +/- 9 mg. kg(-1). d(-1), P = 0.007), but it also showed that the drop could be prevented by adding supplemental protein to the predominantly vegetarian diet (Diet VS) (FSR: 6.4 +/- 0.3%/d, P = 0.08; ASR: 140 +/- 7 mg. kg(-1). d(-1), P = 0.03). Albumin synthesis appears to be modulated by changes in the proportion of animal vs. vegetable protein occurring in the diet. The mechanism might be related to differences in digestibility and consequently in net amino acid availability between diets.

Plasma amino acid concentrations in patients with acute myelogenous leukemia

Changes in plasma-free amino acid (PFAA) concentrations in the presence of solid tumors have been widely described. Conversely, the PFAA profile in patients with acute leukemias is less well defined. The aim of the present study was to clarify whether the PFAA profile is altered in patients with acute myeloid leukemia (AML), whether the profile differs from the PFAA profile of solid tumors, and whether it may predict outcome of AML. Fasting PFAA were measured in 40 untreated, normally nourished patients with AML (17 males, 23 females), ages 22-78 y, with white blood cell (WBC) counts ranging from 1.08 to 276.5 x 10(3)/cm2, and in 24 healthy volunteers. Plasma concentrations (mu mol/L, mean +/- SE) of glutamic acid (GLU), free tryptophan (FTRP), ornithine (ORN), and glycine (GLY) were significantly higher in AML (GLU: 90.2 +/- 6.1 versus 37 +/- 8; FTRP: 7.0 +/- 0.6 versus 4.8 +/- 0.3, P < 0.005; ORN: 108.7 +/- 5.8 versus 78 +/- 6, P < 0.001; GLY: 295.0 +/- 14.8 versus 239 +/- 9, P < 0.01), whereas serine (SER), methionine (MET), and taurine (TAU) were significantly lower in AML than in controls (SER: 109.0 +/- 5.8 versus 130 +/- 4, P < 0.03; MET: 25.5 +/- 1.3 versus 33 +/- 3, P < 0.03; TAU: 46.5 +/- 3.5 versus 81 +/- 2, P < 0.001), and tended to be even lower in patients who had not responded to chemotherapy or had relapsed within 18 mo of enrollment. Such changes were unrelated to age, sex, and WBC count. Changes in PFAA that occur in AML are only in part similar to those observed in solid tumors. The reduction of TAU appears to be a typical feature of AML and might be secondary to the deficiency of its precursors SER and MET. Further studies are under way aimed at clarifying whether PFAA might predict prognosis in AML, whether PFAA is normalized by remission induction, and if its correction may be of any benefit for patients with hematologic malignancies.

Clinical and metabolic effects of different parenteral nutrition regimens in patients undergoing allogeneic bone marrow transplantation

BACKGROUND

Nutrients may interfere with physiological and pathophysiologic mechanisms. The present study was aimed at evaluating whether the differences in the quality of energy substrates administered with total parenteral nutrition (TPN) after cytoreductive therapy may influence the clinical outcome of patients undergoing bone marrow transplantation (BMT).

METHODS

Sixty-six consecutive allogeneic BMT patients with hematologic malignancies were randomized to receive either a glucose-based (100% glucose) or a lipid-based (80% lipid, using an omega-6 long-chain triacylglycerol emulsion + 20% glucose) TPN, providing 146.3 kJ/kg body weight, 1.4 g of protein/kg of body weight, administered from day +1 to day +15 after BMT. Time to engraftment (EGT), incidence of sepsis and metabolic complications (hyperglycemia and hypertriglyceridemia), incidence of acute graft-versus-host-disease (A-GVHD) and relapse, survival at 18 months, incidence of deaths for A-GVHD and relapse were evaluated.

RESULTS

Six patients dropped out before completing the study period. Thirty-one patients in the glucose-based TPN group and 29 patients in the lipid-based TPN group were evaluated. The incidence of hyperglycemia was significantly lower in the lipid-based TPN group than in the glucose-based TPN group (3.4% vs. 32%, respectively; P=0.004). Five patients in the glucose group and none in the lipid group died for A-GVHD (P<0.05). Survival at 18 months tended to be higher in the lipid group than in the glucose group (62% vs. 42%, P=NS). Rate of bone-marrow EGT, time to EGT, incidence of sepsis and fungal infections during TPN, incidence of A-GVHD, and rate of relapse at 18 months were not different in the two groups.

CONCLUSIONS

The results obtained suggest that the use of lipid-based TPN after allogeneic BMT is associated with lower incidence of lethal A-GVHD and hyperglycemia, without negatively affecting the EGT of infused cells. Intravenously administered lipids might have influenced the severity of A-GVHD likely via modulation of immune response and synthesis of cytokines, prostaglandins, and leukotrienes that participate in the pathogenesis of graft-versus-host disease.

[Energy metabolism in cancer patients]

The presence of cachexia as defined by a series of clinical symptoms, such as anorexia, weight loss, muscular atrophy, tissue wasting, altered organ function, is frequently observed in cancer and makes a decisive contribution to morbidity and mortality. The onset of neoplastic cachexia is characterized by two events: the presence of primary or secondary anorexia and alterations of the host's intermediate metabolism. Among the most frequent metabolic alterations described in cancer patients is an absolute or relative increase in basal energy consumption with lack of adaptation to fasting. The causes of increased energy consumption in cancer patients are still not clear. Numerous studies on glucose, fat and protein metabolism induced by cancer have significantly contributed to our understanding of the phenomenon. The main alterations of the glucose metabolism are increased glucose turnover and reduced peripheral utilization, both of which probably depend on the presence of the tumour, as shown by their normalization after treatment. Increased gluconeogenesis, from lactate and from gluconeogenetic AA, is the main factor responsible for increased glucose turnover. The main alterations of the fat metabolism are increased mobilization of lipids from adipose tissues, reduced use of exogenous triglycerides and increased oxidation of free fatty acids that cannot be suppressed by glucose. The main alterations of protein metabolism are increased protein turnover with reduced synthesis and increased degradation of muscular proteins and increased hepatic protein synthesis. Knowledge of the pathogenesis of neoplastic cachexia represents a valuable aid for its effective prevention and treatment.

Mechanism of early tumor anorexia

Whether in tumor-bearing rats a temporal relationship exists between an increase in plasma free tryptophan (FTRP), an increase in brain serotonin (5-HT), and onset of anorexia was studied. Rats were assigned to three groups: tumor-bearing (TB), pair fed (PF), and controls. Food intake was recorded daily. In TB rats anorexia developed on Day 18 and thereafter food intake decreased progressively until end of study. After tumor inoculation, tumor became palpable on Day 10 and continued to grow exponentially until end of study. Rats were killed on Days 6, 10, 16, 18, 22, and 26 to determine plasma FTRP, FTRP/LNAA, and brain 5HT and compared to PF and controls. On Day 6, before tumors became detectable, FTRP and FTRP/LNAA were increased (P < 0.05) in TB rats vs controls. Both continued to increase so that by Day 18 when food intake had started to decrease (P < 0.05), brain 5-HT increased and correlated with the onset of anorexia (R2 = 0.6, P < 0.05). Increases in plasma FTRP the precursor to brain 5-HT occurred in TB rats before physical appearance of tumor and increased until an increase in brain 5-HT occurred, leading to anorexia.

Cancer anorexia: new pathogenic and therapeutic insights

During tumor growth, anorexia and reduced food intake markedly contribute to the development of malnutrition, thus worsening overall patients' survival. A better understanding of the pathophysiology of eating behavior may lead to new and more effective therapies, aiming at counteracting the detrimental effects of anorexia and reduced food intake on nutritional status and survival in cancer patients. Brain tryptophan and serotonin concentrations seem to play a pivotal role in the regulation of eating behavior. Increased brain serotonin activity is indeed associated with a reduction of food intake. It has been recently hypothesized that increased availability of tryptophan to the brain and the consequent increased serotonin activity may represent the pathogenic mechanism for cancer-associated anorexia. According to this hypothesis, the modulation of brain serotonin activity may result in an improvement of anorexia. Reducing brain tryptophan availability represents a possible mechanism to restore brain serotonin activity to normal. There is evidence that the oral administration of neutral amino acids competing with tryptophan for brain entry results in a significant improvement of cancer anorexia. The same treatment may also be effective in improving secondary anorexia, which is associated with other chronic illnesses, including renal and liver failure, sepsis, and so forth, sharing a similar pathogenic mechanism.

Tumor-induced changes in host metabolism: a possible marker of neoplastic disease

A large number of "biologic markers" for cancer have been described, including tumor-associated antigens, ectopic hormones, enzymes, and effects of tumor on the host's metabolism. Although tumors may metabolically differ from each other, they may induce similar derangements in glucose, lipid, and protein metabolism in the host. In particular, changes in carbohydrate metabolism may induce glucose intolerance that may be early and easily detected using an oral glucose tolerance test. Hypertriglyceridemia and reduced exogenous lipid clearance may represent an early marker of deranged lipid metabolism. Changes in protein metabolism, as reflected by plasma amino acid profile, may also represent a new diagnostic tool for cancer. Among other amino acids, free tryptophan seems to be the best candidate as a new useful marker for monitoring neoplastic disease. It is conceivable that, based on the understanding of the differences in plasma amino acid profiles, more specific and rational antineoplastic strategies may arise.

Biochemical indices may not accurately reflect changes in nutritional status after allogeneic bone marrow transplantation

The validity of biochemical indices routinely used for nutritional assessment was evaluated in patients undergoing allogeneic bone marrow transplantation for hematologic malignancies. Sixteen patients received total parenteral nutrition (TPN) for 15 days (35 kcal kg.body wt-1.day-1; 1.4 g amino acid.kg body wt-1.day-1) starting 1 day after transplantation. Nutritional status was evaluated before and after the TPN period by determining anthropometric (body weight, triceps skinfold thickness, and midarm circumference) and biochemical (transferrin, prealbumin, ceruloplasmin, and C3c) indices. Anthropometric indices, which were within the normal range before TPN, were not changed on day 15; transferrin and prealbumin concentrations significantly (p = 0.03) decreased whereas ceruloplasmin and C3c significantly (p = 0.03) increased. The levels of acute-phase proteins (alpha-1-acid glycoprotein, alpha-1-antitrypsin, and C-reactive protein), determined in 8 of the 16 patients at the same time intervals, were increased after 15 days of TPN and were significantly inversely correlated with transferrin and prealbumin. On the basis of these data, it appears that biochemical indices are not sufficiently reliable in the nutritional assessment of bone marrow transplantation patients because the levels of these substances are markedly affected by the acute-phase response secondary to febrile episodes and graft-versus-host disease, which frequently complicate transplantation.

Plasma amino acid imbalance in patients with lung and breast cancer

In order to evaluate whether different solid tumors may specifically influence plasma free amino acid (PFAA) profile, PFAA were analysed in seventy-four patients with lung (41 patients) and breast cancer (33 patients) and 28 healthy subjects. In lung cancer patients a significant reduction of gluconeogenic amino acids, threonine, serine, glycine and a significant increase of free tryptophan and glutamic acid was found. In breast cancer patients a significant increase of ornithine, glutamic acid and free tryptophan was found. The comparison of PFAA profiles between lung and breast cancer suggests that different tumors have a different influence on the host's PFAA pattern.

Cytokines, tryptophan and anorexia in cancer patients before and after surgical tumor ablation

Serotoninergic system activity and cytokine production have been both implicated in the pathogenesis of cancer anorexia. To verify the existence of relationships between tryptophan, cytokines and anorexia, twenty cancer and six non-neoplastic patients were studied. Plasma amino acid concentration, including tryptophan, and spontaneous and LPS stimulated tumor necrosis factor and interleukin-1 release from peripheral blood mononuclear cells were determined before and after surgery in both groups of patients. A close relationship between plasma free tryptophan concentration and anorexia was observed, whereas no relationship between cytokine production and either anorexia or plasma tryptophan was found in cancer patients.

Comparative effects of arginine and other amino acid deprivation on in vitro expression of lymphocyte activation markers

Enteral or parenteral arginine supplementation enhances lymphocyte activation after mitogenic stimulation, in rats and humans. Arginine deprivation in culture media is associated with a reduction of lymphocyte activation; this effect, however, has not yet been proven to be specific for arginine. This study was designed to evaluate the specificity of arginine deprivation from culture media on the reduction of in vitro lymphocyte activation. Peripheral blood mononuclear cells, obtained from 11 healthy volunteers, were cultured in RPMI 1640, selectively deprived of single amino acids (i.e. arginine, phenylalanine, leucine, methionine, and threonine) and supplemented with phytohemagglutinin (PHA). The expression of interleukin-2 receptor and transferrin receptor was evaluated by cytometric analysis; the levels of soluble IL-2 receptor were determined by immuno-enzymatic assay. Results were compared with those obtained by culturing cells in non-deprived, RPMI 1640 medium. The expression of transferrin and IL-2 receptor, as well as the levels of IL-2 soluble receptor, were significantly reduced in all deprived media irrespective of the lacking amino acid. These results suggest that the reduction of in vitro lymphocyte activation is not an arginine specific effect. Therefore, the known enhancement of immune response, following arginine supplementation in vivo, is likely to involve a more complex series of events.

Densitometry-based equations for estimating body composition in Fischer rats

Male Fischer rats are widely used to evaluate the effects of nutritional repletion or deprivation on the rat's nutritional status. Practical methods are needed to evaluate changes in body composition. Chemical analysis is expensive, time consuming, and often not available; bioelectrical impedance analysis in laboratory animals lacks standardization. Postulating that the measurement of densitometry would allow reliable estimation of body composition in the male Fischer rat, we studied 27 male Fischer rats. Densitometric measurements of the carcasses and their chemical analysis were performed to obtain reference values. Initial estimation of the fraction of body fat based on densitometry was attempted with the Siri equation intended for use in humans. We found that this equation was not suitable for use in the male Fischer rat because it underestimated fat mass at high carcass weights and overestimated fat mass at low carcass weights. Therefore, the Siri equation was modified to more accurately predict carcass composition in the male Fischer rat. Three different predictive equations based on simple densitometric measurements were developed that allow separate estimation of carcass fat, carcass water, and carcass protein in the male Fischer rat. These equations were found to be accurate to within 2-5-3% of carcass weight.