Immunologic effects of arginine supplementation in tumor-bearing and non-tumor-bearing hosts

Immunonutrition in Orthopedic and Traumatic Patients

The role of nutrition intervention in surgical settings is constantly developing and evolving. Immunonutrition represents a viable option to reduce perioperative and postoperative complications in surgical oncology. However, as far as we know, little research has been conducted in the orthopedic field. With this review, we aim to summarize the state of the art in the application of immune-enhanced compounds to surgical, orthopedic, and traumatic patients. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were adopted. A comprehensive search was carried out using the PubMed (MEDLINE), EMBASE, and Cochrane Library databases. All the studies dealing with immunonutrition fed to traumatic and orthopedic patients were pooled, the data were extracted, and the studies were discussed. A total of eight studies were included: six focused on trauma surgery and two on elective orthopedic surgery. The epidemiological characteristics of participants and the assessment of results were reported. Data were analyzed using R software (2020; R Core Team). Based on the current available literature, a positive impact of immunonutrition in orthopedic and trauma surgical settings was registered. All studies analyzed showed the favorable impact of the immunonutrition diet on clinical outcomes. The full effect of this type of nutrition and its different applications in the orthopedic and traumatic fields should be critically investigated through more extensive randomized controlled trials.

Could Immunonutrition Help in the Fight against COVID-19 in Cancer Patient?

The rapid and widespread global pandemic of 2019 coronavirus disease (COVID-19) has had unprecedented negative health and economic impacts. Immune responses play a key role in the development of COVID-19, including the disruption of immune balance and cytokine storms caused by excessive inflammatory responses. Due to the effects of cancer itself and treatment, patients often accompanied by immunosuppression appear to be a susceptible population for COVID-19. Worryingly, COVID-19 with cancer is associated with a poor prognosis. Cancer patients are a vulnerable group, threatened by COVID-19, finding a way to combat COVID-19 for them is urgent. Immunonutrition is closely related to balance and strong immune function. Supplementary immunonutrition can improve the immune function and inflammatory response of cancer patients after surgery, which provides evidence for the role of immunonutrition in combating COVID-19. We reviewed possible mechanisms of immunonutrition against COVID-19, including enhancing immune cell function, increasing immune cell count, ameliorating excessive inflammatory response, and regulating gut microbiota. Immunonutrition supplementation in cancer patients may be beneficial to enhance immune function in the early stage of COVID-19 infection and control excessive inflammatory response in the late stage. Therefore, immunonutrition is a potential strategy for the prevention and treatment of COVID-19 in cancer.

The Safety of Preoperative Amino Acid (Elental) Loading in Colon Cancer Surgery: Prospective Cohort Study

The aim of this prospective study was to evaluate the safety of preoperative amino acid plus carbohydrate drink (Elental) loading in colon cancer surgery. Prolonged preoperative fasting increases insulin resistance, and current evidence recommends carbohydrate drinks 2 hours before surgery. We prospectively enrolled consecutive patients with a preoperative diagnosis of colon cancer who underwent surgery. The patients received 600 mL of Elental the night before surgery and 300 mL of Elental 3 hours prior to induction of anesthesia. Primary end point was the safety of preoperative amino acid (Elental) loading in colon cancer surgery. Safety measurement was anastomotic leakage and aspiration pneumonia. Secondary end points were incidence rate of incisional surgical site infection, recovery of bowel movement, length of hospital stay, postoperative nutritional status, and insulin resistance. A total of 80 consecutive patients were enrolled in this study from February 2013 to January 2014. The incidence of anastomotic leakage was 3 patients (3.8%), and there was no aspiration pneumonia. The incidence of incisional surgical site infection was 2 patients (2.5%). The median times of first flatus, defecation after surgery, and postoperative hospital stay were 1 day, 2 days, and 6 days, respectively. The insulin resistance recovered to a preoperative level after 3 days after surgery. The preoperative amino acid plus carbohydrate drink (Elental) loading 3 hours prior to induction of anesthesia in colon cancer surgery is safe, and incisional surgical site infection rate and recovery of bowel movement and insulin resistance are feasible.

l-arginine minimizes immunosuppression and prothrombin time and enhances the genotoxicity of 5-fluorouracil in rats

OBJECTIVE

The aim of this study was to evaluate the effect of low doses of l-arginine supplementation on hemogram, integrity of DNA and spleen, inflammatory infiltrate in the jejunum, and in the coagulogram of rats submitted to 5-fluorouracil (5-FU) chemotherapy.

METHODS

Thirty-two Wistar rats were fed commercial feed and water ad libitum and grouped into four (eight rats per group): The control group was given a 0.9% physiologic solution to simulate the application of 5-FU in the other groups; the G_5-FU group was given a dose of 5-FU; the G_Arg50 and G_Arg100 groups were given a dose of 5-FU and supplemented with 50 and 100 mg l-arginine/d added in the drinking water ad libitum.

RESULTS

The rats in the G_Arg50 group did not lose weight after chemotherapy. G_Arg50 rats presented polycythemia owing to dehydration caused by diarrhea generated by 5-FU. G_Arg100 rats had increased total leukocyte count, eosinophils, lymphocytes, and index in the total index of DNA damage, yet showed a reduction in prothrombin time and in the spleen depletion index. Rats in the G_5-FU, G_Arg50, and G_Arg100 groups had similar moderate inflammatory infiltrate in the jejunum.

CONCLUSION

Supplementation with 100 mg/d of l-arginine minimized immunosuppression, spleen depletion, and prothrombin time and contributed to the breakdown of 5-FU-generated DNA in Wistar rats. Supplementation with 50 mg/d of l-arginine decreased the weight loss generated by 5-FU in Wistar rats. Supplements with 50 or 100 mg of l-arginine did not interfere with 5-FU-generated jejunal inflammatory infiltrate.

Safety and performance benefits of arginine supplements for military personnel: a systematic review

CONTEXT

Dietary supplements are widely used by military personnel and civilians for promotion of health.

OBJECTIVE

The objective of this evidence-based review was to examine whether supplementation with l-arginine, in combination with caffeine and/or creatine, is safe and whether it enhances athletic performance or improves recovery from exhaustion for military personnel.

DATA SOURCES

Information from clinical trials and adverse event reports were collected from 17 databases and 5 adverse event report portals.

STUDY SELECTION

Studies and reports were included if they evaluated the safety and the putative outcomes of enhanced performance or improved recovery from exhaustion associated with the intake of arginine alone or in combination with caffeine and/or creatine in healthy adults aged 19 to 50 years.

DATA EXTRACTION

Information related to population, intervention, comparator, and outcomes was abstracted. Of the 2687 articles screened, 62 articles meeting the inclusion criteria were analyzed. Strength of evidence was assessed in terms of risk of bias, consistency, directness, and precision.

RESULTS

Most studies had few participants and suggested risk of bias that could negatively affect the results. l-Arginine supplementation provided little enhancement of athletic performance or improvements in recovery. Short-term supplementation with arginine may result in adverse gastrointestinal and cardiovascular effects. No information about the effects of arginine on the performance of military personnel was available.

CONCLUSIONS

The available information does not support the use of l-arginine, either alone or in combination with caffeine, creatine, or both, to enhance athletic performance or improve recovery from exhaustion. Given the information gaps, an evidence-based review to assess the safety or effectiveness of multi-ingredient dietary supplements was not feasible, and therefore the development of a computational model-based approach to predict the safety of multi-ingredient dietary supplements is recommended.

L-Arginine supplementation inhibits the growth of breast cancer by enhancing innate and adaptive immune responses mediated by suppression of MDSCs in vivo

Background

L-Arg is involved in many biological activities, including the activation of T cells. In breast cancer patients, L-Arg is depleted by nitric oxide synthase 2 (NOS2) and arginase 1 (ARG-1) produced by myeloid-derived suppressor cells (MDSCs). Our aim was to test whether L-Arg supplementation could enhance antitumor immune response and improve survivorship in a rodent model of mammary tumor.

Methods

Tumor volumes in control and L-Arg treated 4 T1 tumor bearing (TB) BALB/c mice were measured and survival rates were recorded. The percentages of MDSCs, dendritic cells (DCs), regulatory T cells (Tregs), macrophages, CD4⁺ T cells, and CD8⁺ T cells were examined by flow cytometry. Additionally, levels of IL-10, TNF-α, and IFN-γ were measured by enzyme-linked immunosorbent assay (ELISA) and nitric oxide (NO) levels were measured by the Griess reaction. IFN-γ, T-bet, Granzyme B, ARG-1 and iNOS mRNA levels were examined by real-time RT-PCR.

Results

L-Arg treatment inhibited tumor growth and prolonged the survival time of 4 T1 TB mice. The frequency of MDSCs was significantly suppressed in L-Arg treated TB mice. In contrast, the numbers and function of macrophages, CD4⁺ T cells, and CD8⁺ T cells were significantly enhanced. The IFN-γ, TNF-α, NO levels in splenocytes supernatant, as well as iNOS, IFN-γ, Granzyme B mRNA levels in splenocytes and tumor blocks were significantly increased. The ARG-1 mRNA level in tumor blocks, the frequency of Tregs, and IL-10 level were not affected.

Conclusion

L-Arg supplementation significantly inhibited tumor growth and prolonged the survival time of 4 T1 TB mice, which was associated with the reduction of MDSCs, and enhanced innate and adaptive immune responses.

Interest of preoperative immunonutrition in liver resection for cancer: study protocol of the PROPILS trial, a multicenter randomized controlled phase IV trial

BACKGROUND

Malnutrition is an independent risk factor of postoperative morbidity and mortality and it's observed in 20 to 50% of surgical patients. Preoperative interventions to optimize the nutritional status, reduce postoperative complications and enteral nutrition has proven to be superior to the parenteral one. Moreover, regardless of the nutritional status of the patient, surgery impairs the immunological response, thus increasing the risk of postoperative sepsis. Immunonutrition has been developed to improve the immunometabolic host response in perioperative period and it has been proven to reduce significantly postoperative infectious complications and length of hospital stay in patients undergoing elective gastrointestinal surgery for tumors. We hypothesize that a preoperative oral immunonutrition (ORAL IMPACT®) can reduce postoperative morbidity in liver resection for cancer.

METHODS/DESIGN

Prospective multicenter randomized placebo-controlled double-blind phase IV trial with two parallel treatment groups receiving either study product (ORAL IMPACT®) or control supplement (isocaloric isonitrogenous supplement--IMPACT CONTROL®) for 7 days before liver resection for cancer. A total of 400 patients will be enrolled. Patients will be stratified according to the type of hepatectomy, the presence of chronic liver disease and the investigator center. The main end-point is to evaluate in intention-to-treat analysis the overall 30-day morbidity. Secondary end-points are to assess the 30-day infectious and non-infectious morbidity, length of antibiotic treatment and hospital stay, modifications on total food intake, compliance to treatment, side-effects of immunonutrition, impact on liver regeneration and sarcopenia, and to perform a medico-economic analysis.

DISCUSSION

The overall morbidity rate after liver resection is 22% to 42%. Infectious post-operative complications (12% to 23%) increase the length of hospital stay and costs and are responsible for a quarter of 30-day mortality. Various methods have been advocated to decrease the rate of postoperative complications but there is no evidence to support or refute the use of any treatment and further trials are required. The effects of preoperative oral immunonutrition in non-cirrhotic patients undergoing liver resection for cancer are unknown. The present trial is designed to evaluate whether the administration of a short-term preoperative oral immunonutrition can reduce postoperative morbidity in non-cirrhotic patients undergoing liver resection for cancer.

TRIAL REGISTRATION

Clinicaltrial.gov: NCT02041871.

Dietary arginine supplementation enhances immune responses to inactivated Pasteurella multocida vaccination in mice

The present study was conducted to determine the adjuvant effect of arginine in mice immunised with inactivated vaccine. Mice immunised with an inactivated Pasteurella multocida vaccine and fed diets supplemented with 0·2 % (vaccine-0·2 %) or 0·5 % (vaccine-0·5 %) arginine exhibited 100 % protection from a challenge with P. multocida serotype A (CQ2) at a dose of 4·4 × 105 colony-forming units (2LD50; median lethal dose), when compared with mice receiving no arginine supplementation. Meanwhile, antibody titres in the vaccine-0·2 % arginine group were much higher than those in the vaccine-oil adjuvant group before challenge and at 36 h post-infection. Furthermore, immunisation with the inactivated vaccine and dietary supplementation with 0·2 % arginine increased serum levels of glutathione peroxidase, in comparison with immunisation with the inactivated vaccine and an oil adjuvant. Collectively, dietary arginine supplementation confers an immunostimulatory effect in mice immunised with the inactivated P. multocida vaccine. The present results also indicate that optimal supplemental doses of arginine are 0·2-0·5 % in the mouse model.

Effect of arginine on angiogenesis induced by human colon cancer: in vitro and in vivo studies

This study investigated the effect of arginine (Arg) supplementation on angiogenesis in human colon cancer. The in vitro study investigated the effects of different Arg levels and inducible nitric oxide (iNO) synthase inhibitor on angiogenic protein expressions stimulated by SW480 cells. The results showed that the production of vascular endothelial growth factor (VEGF), basic fibroblast growth factor with 100 and 1000 micromol/L Arg and matrix metalloproteinase (MMP)-2 with 1000 micromol/L Arg was lower than that with 0 and 50 micromol/L Arg. Inhibition of iNO resulted in higher angiogenic protein expressions comparable with groups with low Arg administration, indicating that Arg administration at levels similar to or higher than physiological concentrations reduced the progression of colon cancer, and iNO may partly play a role in reducing angiogenesis. The in vivo study used a human colon cancer xenograft model in nude mice. Mice were inoculated with 1x10(7) SW480 cells and assigned to two groups. The control group was fed a semipurified diet, while the experimental group was supplied an Arg-supplemented diet. After 5 weeks, tumors were harvested and spleens were excised for further analysis. Results showed that the MMP-2, MMP-9 and VEGF receptor levels in tumors were significantly lower, whereas tumor NO levels and spleen natural killer (NK) cell activities were higher in the Arg group than in the control group. These results were consistent with the in vitro study that dietary Arg supplementation inhibits the progression of colon cancer possibly by increasing NO secretion and consequently enhancing NK cell activity.

Perioperative immune responses in cancer patients undergoing digestive surgeries

Background

Th1/Th2 cell balance is thought to be shifted toward a Th2-type immune response not only by malignancy but also by surgical stress. The aim of this study was to estimate perioperative immune responses with respect to the Th1/Th2 balance in patients with gastrointestinal cancer.

Methods

Ninety-four patients who underwent abdominal surgeries were divided into three groups: gastric resection (n = 40), colorectal resection (n = 34) and hepatic resection (n = 20). Twelve patients undergoing laparoscopic cholecystectomy and 20 healthy subjects were served as control groups. Intracellular cytokine staining in CD4+ T lymphocytes was identified to characterize Th1/Th2 balance. Th1/Th2 balance was evaluated before operation and until postoperative days (POD) 14.

Results

The preoperative Th1/Th2 ratio was significantly lower in patients with malignancy compared with control. The Th1/Th2 ratio of patients in all groups decreased significantly postoperatively. Th1/Th2 balance on POD 2 in patients with malignancy was significantly decreased compared to patients with laparoscopic cholecystectomy, but there were no significant differences among the four groups on POD 14.

Conclusion

Patients with malignancy showed an abnormal perioperative Th1/Th2 balance suggesting predominance of a type-2 immune response. Major abdominal surgeries induce a marked shift in Th1/Th2 balance toward Th2 in the early postoperative stage.

Pros and cons of L-arginine supplementation in disease

The amino acid arginine and one of its metabolites NO have gathered broad attention in the last decade. Although arginine is regarded as a conditionally essential amino acid in disease, L-arginine supplementation in severe illness has not found its way into clinical practice. This might be due to the invalid interpretation of results from studies with immune-enhancing diets containing L-arginine amongst other pharmaconutrients. However, not much attention is given to research using L-arginine as a monotherapy and the possibility of the alternative hypothesis: that L-arginine supplementation is beneficial in disease. The present review will discuss data from studies in healthy and diseased animals and patients with monotherapy of L-arginine to come to an objective overview of positive and negative aspects of L-arginine supplementation in disease with special emphasis on sepsis, cancer, liver failure and wound healing.

L-arginine supplementation does not affect chemically induced carcinogenesis and tumor growth in BALB-c mice

T-cell zeta-chain downregulation is common in various types of cancer and it is proposed as a mechanism of cancer immunosubversion. L-arginine consumption by arginase rich suppressor myeloid cells has been incriminated. The effect of L-arginine supplementation on chemically induced carcinogenesis and tumor growth in mice was evaluated.

METHODS

Eight-week old female BALB-c mice were used. Ten mice were injected i.m. with 0.6 mg methylcholanthrene (MCA) once. Ten mice were injected with MCA once and were receiving L-arginine supplementation (5% in animal drinking water) continuously during the study. Mice with cancer were sacrificed 12 weeks after.

RESULTS

From the 10 MCA injected mice 6 developed sarcoma. From the 10 MCA injected mice that were receiving L-arginine supplementation 7 developed sarcoma. L-arginine supplementation did not affect MCA induced carcinogenesis (p=1.0, Fisher's exact test). The weight of tumors was not different between the tumors derived from mice that were or were not receiving L-arginine supplementation (1088.3+/-590.2 mg vs. 969.6+/-608.1 mg respectively, p=0.729, unpaired t-test).

CONCLUSION

L-arginine supplementation does not affect chemically induced carcinogenesis and tumor growth in BALB-c mice. Although zeta-chain downregulation could be a mechanism of cancer immunosubversion there are enough other cancer immunosubversion mechanisms that were not overwhelmed by L-arginine supplementation. Additionally, except cancer immunosubversion, cancer immunoselection is another, possibly more significant, mechanism of tumor escape from immunosurveillance.

Favorable effects of preoperative enteral immunonutrition on a surgical site infection in patients with colorectal cancer without malnutrition

PURPOSE

A prospective study was conducted to ascertain the effects of preoperative enteral immunonutrition on a surgical site infection (SSI) in patients with colorectal cancer without malnutrition.

METHODS

Patients with colorectal cancer undergoing elective surgery without malnutrition, bowel obstruction, severe cardiopulmonary complications, diabetes, collagen disease, or renal failure were sequentially divided into an immunonutrition group (n = 33) and a control group (n = 34). In the immunonutrition group, an enteral diet supplemented with arginine, dietary nucleotides, and omega-3 fatty acids was administered for 5 days (750 ml/day) prior to surgery.

RESULTS

The mean age was slightly higher in the immunonutrition group (69 +/- 9 years) than in the control group (63 +/- 11 years; P < 0.05), but no significant differences between the groups were noted for the body mass index, total protein, albumin, hemoglobin, surgical methods, operation time, or volume of intraoperative bleeding. The frequencies of superficial incisional SSI, deep incisional SSI and organ/space SSI in the immunonutrition and control groups were 0% and 11.8% (4/34; P < 0.05), 0% and 0%, and 0% and 2.9% (1/34), respectively.

CONCLUSION

Preoperative enteral immunonutrition appears to be effective for preventing SSI in patients with colorectal cancer without malnutrition.

Early postoperative jejunostomy feeding with an immune modulating diet in patients undergoing resectional surgery for upper gastrointestinal cancer: A prospective, randomized, controlled, double-blind study

BACKGROUND

The provision of perioperative immune modulating enteral feeds after major surgery may result in reduced infective complications, but meta-analyses have not demonstrated a survival advantage. The aim of this study was to determine whether early postoperative immune modulating jejunostomy feeding results in reduced infective complications in patients undergoing resectional surgery for upper gastrointestinal cancer.

METHODS

A total of 120 patients undergoing resection for cancers of the pancreas, oesophagus and stomach were randomized in a double-blind manner to receive jejunostomy feeding with an immune modulating diet (Stresson-Group A) or an isonitrogenous, isocaloric feed (1250 Calories and 75 g protein/l--Nutrison High Protein-Group B) for 10-15 days. Feeding was commenced 4h postoperatively and continued for 20 h/day. The target volume (ml/h) was 25 on day 0, 50 on day 1, and 75 thereafter. Outcome measures included complications, hospital stay and mortality.

RESULTS

A total of 108 patients (54 in each group) were analysed. Feed delivery, although less than targeted, was similar in both groups. There were 6 (11%) deaths in each group. Median (IQR) postoperative hospital stay was 14.5 (12-23) days in Group A and 17.5 (13-23) days in Group B (P=0.48). A total of 24 (44%) patients in each group had infective complications (P=1.0). A total of 21 (39%) patients in Group A and 28 (52%) in Group B had non-infective complications (P=0.18). Jejunostomy-related complications occurred in 26 (48%) patients in Group A and 30 (56%) in Group B (P=0.3).

CONCLUSION

Early postoperative feeding with an immune modulating diet conferred no outcome advantage when compared with a standard feed.

Plasticity of neuroendocrine-thymus interactions during ontogeny and ageing: role of zinc and arginine

Thymic re-growth and reactivation of thymic functions may be achieved in old animals by different endocrinological or nutritional manipulations such as, (a) treatment with melatonin, (b) implantation of a growth hormone (GH) secreting tumour cell line (GH3 cells) or treatment with exogenous GH, (c) castration or treatment with exogenous luteinizing hormone-releasing hormone (LHRH), (d) treatment with exogenous thyroxin or triiodothyronine, and (e) nutritional interventions such as arginine or zinc supplementation. These data strongly suggest that thymic involution is a phenomenon secondary to age-related alterations in neuroendocrine-thymus interactions and that it is the disruption of these interactions in old age that is responsible for age-associated immune-neuroendocrine dysfunctions. The targets involved in hormones-induced thymic reconstitution may directly or indirectly involve hormone receptors, cytokines, arginine, and a trace element such as zinc, which is pivotal for the efficiency of neuroendocrine-immune network during the whole life of an organism. The effect of GH, thyroid hormones, and LHRH may be due to specific hormone receptors on thymocytes and on thymic epithelial cells (TECs), which synthesize thymic peptides. Melatonin may also act through specific receptors on T-cells. In this context, the role of zinc, which turnover is reduced in old age, is pivotal because of its involvement through zinc fingers in the gene expression of hormone receptors. In addition, the effects of zinc are multifaceted: from the reactivation of zinc-dependent enzymes, to cell proliferation and apoptosis, to cytokines expression and to the reactivation of thymulin, which is a zinc-dependent thymic hormone required for intrathymic T-cell differentiation and maturation as well as for the homing of stem cells into the thymus. Zinc is also required for arginine action, via NO pathway. The role of zinc is therefore crucial in neuroendocrine-thymus interactions. According to data in animals and humans, the above reported endocrinological manipulations (GH, thyroid hormones, and melatonin) or arginine treatment may also act via zinc pool in restoring thymic activity in ageing allowing improvements on peripheral immune efficiency.

In vivo arginine production and intravascular nitric oxide synthesis in hypotensive sepsis

BACKGROUND

Arginine is important in the response to infections and is a precursor for the synthesis of the vasodilator nitric oxide (NO). Low plasma arginine is correlated with a worse prognosis in patients with sepsis, and increased NO has been implicated in the hypotension of sepsis. Data on in vivo arginine and NO kinetics are lacking in hypotensive septic adults.

OBJECTIVE

We aimed to measure in vivo arginine production and the intravascular NO synthesis rate in hypotensive septic patients.

DESIGN

Arginine flux and the fractional and absolute synthesis rates of plasma NO were measured in fasted healthy (n = 10) and hypotensive septic (n = 6) adults by using a 6-h constant infusion of [15N2-guanidino]arginine. Urinary excretion of the NO metabolites nitrite and nitrate (NOx) and plasma concentrations of NOx, arginine, and creatinine were also measured.

RESULTS

All patients had hyperdynamic septic shock and impaired renal function. Compared with the control subjects, the patients had slower arginine flux (99 +/- 8 compared with 50 +/- 7 micromol x kg(-1) x h(-1); P < 0.01), lower plasma arginine concentrations (75 +/- 8 compared with 40 +/- 11 micromol/L; P < 0.01), higher plasma NOx concentrations (30 +/- 4 compared with 65 +/- 1.8 micromol/L), and a slower fractional synthesis rate of NOx. There was no significant difference in the absolute synthesis rate of NOx between groups. In patients with sepsis, the plasma NOx concentration correlated with the glomerular filtration rate and plasma creatinine but not with mean arterial pressure.

CONCLUSIONS

Patients with septic shock have a shortage in the availability of arginine associated with a slower production. Impaired renal excretion of NOx is a contributor to the high plasma NOx in these patients.

l-Arginine stimulates immune response in chickens immunized with intermediate plus strain of infectious bursal disease vaccine

Infectious bursal disease continues to pose an important threat to the commercial poultry industry, especially after the emergence of virulent infectious bursal disease virus (IBDV). L-arginine, a ubiquitous, basic amino acid is used as an immunostimulant in variety of human and animal studies with great success in immunosuppressed hosts. In the present study, we evaluated the immunomodulatory effects of L-arginine on humoral and cellular immune response in chickens immunized with live intermediate plus (IP) strain of IBDV vaccine. Chickens vaccinated with IP strain and supplemented with 2% L-arginine showed 100% protection after challenge with virulent IBDV compared to 80% protection induced by IP strain alone. IP strain vaccine elicited good antibody titres in both the groups, IP + L-arginine and IP alone, however, the antibody titres in IP + L-arginine group were significantly higher (P < 0.05) than IP vaccinated chickens. Mitogenic response of peripheral blood lymphocytes to specific IBDV antigen stimulation was significantly higher in IP + L-arginine group (P < 0.05). Peripheral blood lymphocytes were able to rapidly clear the suppressive effects of IP strain and virulent challenge virus in IP + L-arginine group. These results strongly suggest that l-arginine plays a vital role in modulation of protective immune response against IBDV.

Plasma arginine concentrations are reduced in cancer patients: evidence for arginine deficiency?

BACKGROUND

The disturbances leading to cancer cachexia remain to be unraveled. Preliminary evidence suggests that arginine availability in cancer is reduced. However, no valid data are available on plasma arginine concentrations in cancer patients.

OBJECTIVE

We aimed to determine whether there is evidence for disturbed arginine metabolism in cancer.

DESIGN

We measured plasma arginine concentrations postabsorptively in patients with various types of tumors, hypothesizing that arginine concentrations would be lower than those in age- and sex-matched control subjects. Patients with localized tumors with a range of metabolic implications were studied: breast cancer (no weight loss), colonic cancer (sometimes weight loss), and pancreatic cancer (usually weight loss). Plasma amino acid concentrations were measured by HPLC.

RESULTS

Plasma arginine concentrations were lower in patients with cancer (breast cancer: 80 +/- 3 compared with 103 +/- 9 micromol/L; colonic cancer: 80 +/- 3 compared with 96 +/- 7 micromol/L; pancreatic cancer: 76 +/- 5 compared with 99 +/- 7 micromol/L; P < 0.05 versus respective age- and sex-matched control subjects), irrespective of tumor type, weight loss, tumor stage, or body mass index (correlations with P > 0.05).

CONCLUSIONS

Malignant tumors associated with various degrees of metabolic derangements are all associated with decreased plasma arginine concentrations, even without weight loss. This suggests that decreased arginine availability is a specific feature of the presence of cancer. These disturbances in arginine metabolism could contribute to the cascade of metabolic events leading to cancer cachexia.

Metabolic and hematological effects of dietary supplementation with arginine on rats bearing ascitic Walker 256 tumor

The notion of using supplementary quantities of arginine for nutritional support in patients with cancer has been evaluated not only as supplement intake of nitrogen substrate but also for its immunopharmacological effects capable of improving the patient's prognosis. The aim of the present study is to evaluate the effects of dietary supplementation with arginine on metastatic dissemination, amino acid metabolism, hematological functions of rats with Walker 256 ascitic tumor. Animals were inoculated intraperitoneally with approximately 4 million cells. Nutritional solutions containing 4 or 6% arginine or just a control diet without added arginine, were administered to the animals via esophagic gavages. The rate of metastasis was lower in animals supplemented with arginine at 4 and 6%. Amino acid metabolism was stimulated in tumor-bearing animals after receiving 4 or 6% arginine, demonstrated by significant increase of arginine, ornithine, citrulline, proline and histidine levels in the blood (p < or = 0.001) when compared to the control diet group. Anemia was less severe in tumor-bearing animals that received arginine supplementation. The findings suggest that arginine supplementation at 6% may have a beneficial effect on to the host, besides its pharmacological action.

A highly effective and stable bispecific diabody for cancer immunotherapy: cure of xenografted tumors by bispecific diabody and T-LAK cells

PURPOSE

In the field of cancer immunotherapy research, the targeting of effector cells with specific antibodies is a very promising approach. Recent advances in genetic engineering have made it possible to prepare immunoglobulin fragments consisting of variable domains using bacterial expression systems.

METHODS

We have produced an anti-epidermal growth-factor receptor (EGFR) x anti-CD3 bispecific diabody (Ex3 diabody) in an Escherichia coli (E. coli) expression system with refolding method. The Ex3 diabody targets lymphokine-activated killer cells with a T-cell phenotype (T-LAK cells) to EGFR positive bile duct carcinoma cells with dramatic enhancement of cytotoxicity in vitro. This specific killing of EGFR-positive cells was completely inhibited by parental mAb IgGs directed to EGFR and the CD3 antigen.

RESULTS

When T-LAK cells were cultured with EGFR-positive tumor cells in the presence of Ex3 diabody, they produced much higher levels of IFN-gamma, GM-CSF, and TNF-alpha than in its absence, this being a possible mechanism underlying specific antitumor activity. The Ex3 diabody showed good stability when tested at 37 degrees C for 48 h, and also markedly inhibited tumor growth of bile duct carcinoma xenografts in severe combined immunodeficient (SCID) mice. When Ex3 diabody (20 microg/mouse) was administrated intravenously, together with T-LAK cells and interleukin-2 (IL-2), complete cure of tumors were observed in three of six mice, and the other three showed marked retardation of tumor growth.

CONCLUSION

The Ex3 diabody can be considered a highly promising reagent for study of specific targeting immunotherapy against bile duct and other EGFR-positive carcinomas.

Arginine and immunity: a unique perspective

Arginine functions in the body as a free amino acid, a component of most proteins, and the substrate for several non-protein, nitrogen-containing compounds, many of which function in immunity. Although arginine is synthesized in the body, it is not made in sufficient quantities to support growth or meet metabolic requirements during periods of stress. Based on the biochemical and physiological role of arginine in maintaining health and immunity, arginine is being added at pharmacologic concentrations to enteral formulas to boost immune function. Unfortunately, animal and human studies that investigate enteral arginine supplementation as the single variable do not show clear immunologic benefit. The inconsistent effects of arginine supplementation on immune function are due to numerous factors, such as the amount and timing of arginine supplementation, the animal species or strain of species, and the experimental model. Systematic study is required to determine whether a basal dietary intake of arginine is required to maintain immune function during health and how much arginine is required to meet metabolic requirements during periods of growth or stress.

Dietary arginine intake alters avian leukocyte population distribution during infectious bronchitis challenge

Although dietary arginine is a factor in immune function and disease resistance, the full range of effects has yet to be described. In this study, the effects of dietary arginine on leukocyte population changes were examined in the peripheral blood and the respiratory tract of chickens inoculated with infectious bronchitis virus (IBV) strain M41. At 2 wk of age, female line P2a White Leghorn-type chickens were randomly assigned to one of three diets with different arginine levels: a marginally deficient diet (0.5%), an adequate diet (1.0%), and a diet containing a high level of arginine (3.0%). All birds were inoculated with IBV at 4 wk of age, and then the peripheral blood and the respiratory lavage were collected at 1 and 7 d postinfection (DPI). The growth rate of birds that received 0.5% arginine was significantly lower than that of birds receiving 1.0 or 3.0% arginine, whereas the growth of the latter groups did not differ. The percentage and absolute number of heterophil (H) and the H/lymphocyte (L) ratio in the peripheral blood at 1 DPI significantly increased as dietary arginine increased. In the respiratory lavage at 1 DPI, the percentage of H also increased with dietary arginine increase. At 7 DPI, the percentage of CD8+ cells from birds fed the deficient diet was lower than those from birds fed the adequate diet and the diet containing a high level of arginine, whereas the cell surface density of CD8 antigen did not vary among groups. These results show that dietary arginine influences the character of the chicken cellular response to IBV and the distribution of responding leukocyte subpopulations in a target tissue for the infection.

Specific reversible stimulation of system y(+) L-arginine transport activity in human intestinal cells

L-Arginine, which is intimately involved in cellular immune functions and nitric oxide biology, is transported by intestinal cells largely via transport System y(+). The gut epithelium is exposed to various luminal amino acids at any given time, and therefore the purpose of this study was to study the regulation of luminal arginine transport by other amino acids. System y(+) L-arginine transport activity was measured in Caco-2 monolayers exposed to various amino acids. L-arginine and/or other System y(+) substrates specifically upregulated System y(+) transport activity twofold after 1 hour, with a response noted as early as 5 minutes. Non-System y(+) substrates did not affect L-arginine absorption. Kinetic analysis indicated that L-arginine exposure increased both System y(+) K(m) and V(max). Neither cycloheximide nor actinomycin affected this stimulation, indicating that the regulation did not involve transcription or translation. The System y(+) substrate activation effect was reversible. L-arginine transport activity returned to baseline within 3 hours when cells were reincubated in amino acid-free media. These data indicate that System y(+) arginine transport activity is rapidly and reversibly activated by System y(+) substrates via a mechanism consistent with transmembrane stimulation. These findings identify a mechanism by which luminal nutrients regulate arginine uptake by the gut.

Immune-modulatory actions of arginine in the critically ill

Current trials of immune-enhancing diets suggest several beneficial clinical effects. These products are associated with a reduction in infectious risk, ventilator days, ICU and hospital stay. However, methodological weaknesses limit the inferences we can make from these studies. Furthermore, improvements in outcomes were largely seen in surgical patients and in patients who tolerated critical amounts of formula. We propose that the beneficial findings cannot easily be extrapolated to other patient populations since there is suggestion from clinical trials that the sickest patients, especially those with severest appearances of sepsis, shock and organ failure may not benefit or may even be harmed. In these conditions we hypothesize that systemic inflammation might be undesirably intensified by immune-enhancing nutrients like arginine in critically ill patients. In this paper, we review the purported effects of arginine on the immune system and organ function to understand the scientific rationale for its inclusion into enteral feeding products. We conclude that patients with the most severe appearances of the systemic inflammatory response syndrome should not receive immune-enhancing substrates which may aggravate systemic inflammation and worsen clinical outcomes.

Arginine-genotype interactions and immune status

The effects of arginine on selective immune responses were investigated in a high arginine-requiring (HA) and low arginine-requiring (LA) strain of chickens. Female chickens from these strains were fed diet containing a nutritionally inadequate level of arginine (0.53% arginine diet) or a surfeit level of arginine (1.53% arginine diet) for 2 weeks. Compared to LA chickens, HA chickens showed a higher feed efficiency, body weight gain, and relative thymus and spleen weights with L-arginine supplementation (p < 0.05). In both HA and LA chickens, a deficiency of arginine significantly decreased the delayed-type hypersensitivity response (p < 0.05) and nitric oxide (NO) production from macrophages. Chickens of the HA strain had higher NO production than those of LA strain with E. coli lipopolysaccharide (LPS) activation. This study indicates that dietary arginine concentration influences the immune status of chickens and that strains that differ in arginine requirements for growth may differ in their arginine needs for immune function.

Growth inhibition of subcutaneously transplanted hepatomas without cachexia by alteration of the dietary arginine-methionine balance

Previous studies have shown that alteration of the dietary arginine-methionine balance by use of synthetic L-amino acids inhibits tumor growth of a subcutaneously transplanted Morris hepatoma at the expense of maintaining body weight. However, L-methionine is susceptible to degradation and, therefore, may contribute to a deficiency state. The present studies were performed to determine whether growth of subcutaneous hepatoma transplants is inhibited, and body growth maintained, when rats are fed diets containing L-methionine in replacement of N-acetyl-L-methionine (NALM) for 28 days. Tumor-free and tumor-bearing rats fed a control diet, with amino acids replacing protein, had gains in body weight: 31.3 +/- 1.0 and 19.1 +/- 0.5 g (12% and 7%), respectively. Rats fed six experimental diets, with varying L-arginine-NALM balances, had body weight gains ranging from 18.4 +/- 0.3 to 26.7 +/- 0.9 g (7-10%). Tumor weight of control rats was 10.65 +/- 0.24% of body weight. Diets supplemented with L-arginine in combination with normal and deficient NALM decreased tumor weights by 35% and 38%, respectively, It is concluded that dietary replacement of L-methionine with NALM and supplementation with L-arginine inhibits growth of a subcutaneously transplanted Morris hepatoma in the absence of cachexia.

First synthesis of totally orthogonal protected alpha-(trifluoromethyl)- and alpha-(difluoromethyl)arginines

The first synthesis of a series of totally orthogonal protected racemic alpha-(trifluoromethyl)- and alpha-(difluoromethyl)arginines is described. The key steps of the synthesis are the mild guanidinylation procedure and the selective hydrogenation of a CC triple bond in the presence of a Cbz-group.

Influence of dietary arginine concentration on lymphoid organ growth in chickens

In vivo effects of graded dietary levels of arginine on the body and lymphoid organs were investigated using Cornell K strain chickens of the B15/B15 haplotype. Two-week-old birds were fed an arginine-deficient basal diet (0.53% arginine) supplemented with additional arginine (up to 1.0% L-arginine to the diet). At four weeks of age, body weight, lymphoid organ weight, and concentrations of amino acids in plasma were measured. Arginine supplementation produced significant increases in plasma arginine (from 200 nM in chicks fed the basal diet to 2,000 nM in chicks receiving the 1.5% arginine diet) and ornithine concentrations (from 17 nM in chicks fed the basal diet to 500 nM in chicks receiving the 1.5% arginine diet). The arginine-deficient diet reduced body weight gain (P < 0.0001) and thymus, spleen, and bursa of Fabricius weights (P < 0.05). In contrast to the bursa weight, the thymus and spleen weights, as percentages of body weight, were also decreased (P < 0.05). This study suggests that arginine markedly influences lymphoid organ development, with a more pronounced effect on the thymus and spleen than on the bursa of Fabricius.

Decreased nitric oxide-mediated natural killer cell activation in chronic fatigue syndrome

BACKGROUND

L-Arginine (L-Arg), one of the essential amino acids, has been reported to have an immunomodulatory effect. The precise mechanism of the L-Arg-induced natural killer (NK) cell activation remains unresolved,and the effect of L-Arg on NK cells in chronic fatigue syndrome (CFS) patients has not been estimated.

METHODS

NK cell function was evaluated in 20 subjects with CFS and compared with that in 21 healthy individuals.

RESULTS

In healthy control subjects, NK activity was significantly increased after treatment with L-Arg, an NK function enhancer, for 24 h, whereas the same treatment failed to enhance NK activity in the CFS patients. We thus focused on L-Arg metabolism, which involves nitric oxide (NO) production through NO synthase (NOS). The expression of inducible NO synthase (iNOS) transcripts in peripheral blood mononuclear cells was not significantly different between healthy control subjects and CFS patients. The L-Arg-mediated NK cell activation was abolished by addition of NG-monomethyl-L-arginine, an inhibitor for iNOS. Furthermore, incubation with S-nitroso-N-acetyl-penicillamine, an NO donor, stimulated NK activity in healthy control subjects but not in CFS patients.

CONCLUSION

These results demonstrate that the L-Arg-induced activation of NK activity is mediated by NO and that a possible dysfunction exists in the NO-mediated NK cell activation in CFS patients.

Immunonutrition: the role of arginine

Clearly, arginine has great potential as an immunomodulator and may prove useful in catabolic conditions such as severe sepsis and postoperative stress. there is a body of evidence suggesting that supplemental arginine upregulates immune function and reduces the incidence of postoperative infection. More modest improvements in nitrogen balance have been observed. Tumor response to arginine appears to depend on the immunogenicity of the particular tumor and on the requirement of arginine by the tumor as a growth substrate. Of note, ornithine shares the thymotrophic, immunostimulatory and secretagogue effects of arginine. It is, therefore, likely that these compounds share the same cellular mechanism of action or that arginine acts via increasing the concentration of available ornithine. The role of arginine in the injured patient and in the tumor-bearing host demands additional study based on the promising experimental evidence regarding the supplemental use of arginine.

Metabolic alteration in patients with cancer: nutritional implications

During the past 20 years, efforts have been made to elucidate the metabolic changes observed in patients with cancer by using stable and radioactive isotopic tracers. These metabolic changes in patients with cancer may be similar to those in other stress conditions, in which glucose production and utilization, lipolysis and free fatty acid flux, and net protein catabolism are increased. Stress hormones, such as glucagon and catecholamines, and certain cytokines may be responsible for these metabolic changes. Although it has been shown that cachexia in patients with cancer signals a poor prognosis, efforts to improve the clinical outcomes with nutritional support have been disappointing. The failure of cancer patients to respond to nutritional support may be related to an alteration in the intermediate metabolism. Therefore, further research evaluating the metabolic abnormalities associated with cancer may lead to more effective nutritional therapies.

Influence of arginine, omega-3 fatty acids and nucleotide-supplemented enteral support on systemic inflammatory response syndrome and multiple organ failure in patients after severe trauma

This study investigated the influence of an enteral diet supplemented with arginine, omega-3 fatty acids, and nucleotides (Impact, Sandoz Nutrition, Berne, Switzerland) on the incidence of systemic inflammatory response syndrome (SIRS) and multiple organ failure (MOF) in patients after severe trauma. Thirty-two patients with an injury-severity score > 20 were included in this prospective, randomized, double-blind, controlled study. Primary endpoints were the incidence of SIRS and MOF. Secondary endpoints were parameters of acute phase and immune response as well as infection rate, mortality, and hospital stay. For statistical analysis 29 patients (test group n = 16, control n = 13) were eligible. In the test group, significantly fewer SIRS days per patient were found during 28 d. The difference was highly significant between d 8-14 (P < 0.001). MOF score was significantly lower in the test group on d 3 and d 8-11 (P < 0.05). Acute phase parameters showed lower C-reactive protein serum levels (significant on D day 4) and fibrinogen plasma levels (significant on d 12 and 14; P < 0.05). HLA-DR expression on monocytes showed significantly higher fluorescence activity on d 7. No significant difference was found for T-lymphocyte CD4/CD8 ratio, interleukin-2 receptor expression, infection rate, mortality (2/16 vs. 4/13), and hospital stay. The results of the study provide further support for beneficial effects of arginine, omega-3-fatty acids and nucleotide-supplemented enteral diet in critically ill patients.

A parenteral nutrition regimen with ornithine substituted for arginine alters the amino acid, but not polyamine, content of the ward colon tumor

Substituting ornithine for arginine in total parenteral nutrition (TPN) regimens eliminates the TPN-enhanced growth of the Ward colon tumor. Plasma arginine was increased when tumor growth was increased, suggesting a role for this amino acid. The erythrocyte polyamine content, however, was elevated in rats receiving both TPN regimens, indicating an increased synthesis and availability for tumors receiving arginine- and ornithine-containing regimens. The objective of this study, therefore, was to evaluate the effect of substituting ornithine for arginine in a TPN regimen on the amino acid and polyamine content of the Ward colon tumor compared with that of rats fed chow ad libitum. Male Fischer 344 rats with a transplantable Ward colon tumor implanted subcutaneously were randomized to three groups and fed for four days. One group received a TPN regimen with arginine (1,300 mg/100 ml, ENA), whereas a second group received a regimen with an isonitrogenous substitution of ornithine (ENO). A control group received chow ad libitum. Serum and tumors were evaluated for arginine, ornithine, lysine, and polyamine content. The arginine concentration in the serum and tumor increased when rats received ENA. In contrast, the serum and tumor arginine content for rats receiving ENO was significantly lower than that for rats receiving chow or ENA. Tumor and serum ornithine content was increased severalfold when ornithine was included in the regimen. Tumor polyamine content was not affected by TPN. The results show that serum and tumor arginine content are significantly altered by substituting ornithine for arginine in a TPN regimen. These and previous results suggest that TPN-enhanced growth of the Ward colon tumor when arginine is included in the formulation occurs by a mechanism other than increased polyamine synthesis.

Increased L-arginine transport in a nitric oxide-producing metastatic colon cancer cell line

BACKGROUND

Little is known about amino acid transport in human neoplastic cells. We previously characterized L-arginine transport in the primary human colon cancer cell line, SW480, and found it is principally mediated by the sodium-independent system y+. In this study, we characterized L-arginine transport in the metastatic cell line, SW620, and compared it with that in the primary cell line, SW480.

METHODS

Transport of 3H-L-arginine in cell monolayers was analyzed in the presence and absence of sodium. Kinetic studies were performed over a range of L-arginine concentrations to determine transporter affinity (Km) and maximal transport velocity (Vmax). Transport was further characterized through blockade with known amino acids. In addition, the effect of cell age (i.e., time in culture) on arginine transport was examined at 2 and 9 days after seeding. Cellular proliferation was assessed by using the colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay.

RESULTS

L-Arginine uptake was primarily sodium independent in the SW620 cell line. Kinetic and amino acid-inhibition studies revealed a single high-affinity, sodium-independent L-arginine transporter (Vmax = 1286.3 +/- 158.3 pmol/mg protein/30 s; Km = 46.8 +/- 4.2 microM). Sodium-independent transport was blocked by system y+ substrates L-homoarginine, L-ornithine and L-lysine. Sodium-dependent uptake occurs through a single transporter with system BO,+ characteristics (Km = 16.15 +/- 2.1 microM; Vmax = 329.94 +/- 29.7 pmol/mg protein/30 s). Arginine transport increased with time in culture with day 2 cells transport velocity = 241.7 +/- 33.6 pmol/mg protein/30s, whereas day 9 cells transport velocity = 377 +/- 15.4 pmol/mg protein/30 s (p < 0.01). Cellular-proliferation studies revealed a doubling time of 3.2 days for SW620 and 5.4 days for SW480 (p < 0.05).

CONCLUSIONS

L-Arginine transport in these neoplastic cell lines occurs primarily through sodium-independent, high-affinity system y+. Vmax was increased 180% in the metastatic variant (SW620), suggesting upregulation of the Y+ transporter. The increased Y+ activity may be a mechanism to provide continuous substrate for tumor growth.

[Malnutrition and immunodeficiency in children]

Our knowledge on relationships between nutrition, immunity and infection has much progressed. Malnutrition affects all three defence mechanisms: unspecific immunity, cellular immunity and humoral immunity. Any kind of nutriment is concerned: nitrogen-caloric nutriments, trace elements, vitamins. Restoration and maintenance of a good nutritional status have become imperative in order to stop the vicious cercle of malnutrition-infection in infants and children.

Supplemental L-arginine HCl augments bacterial phagocytosis in human polymorphonuclear leukocytes

That L-arginine (L-Arg) augments the host response to acute bacterial sepsis suggests that this amino acid intervenes early in the immune response, perhaps via the nitric oxide synthetase (NOS) pathway. The effect of L-Arg supplementation on in vitro phagocytosis of fluorescein-labeled, heat-killed Staphylococcus aureus by peripheral blood neutrophils (PMNs) from 12 normal human volunteers was studied. Separated PMNs were incubated for 2 h with labeled bacteria, with and without supplemental L-Arg, D-arginine, glycine, and/or the NOS inhibitors L-canavanine, aminoguanidine, or L-NG-nitroarginine methyl ester. PMNs were fixed and extracellular fluorescence quenched with crystal violet. By flow cytometry and confocal microscopy, L-Arg supplementation was shown to result in a highly significant increase in PMN bacterial phagocytosis, the maximal effect being seen with L-Arg 380 microM and falling off with higher concentrations. This augmentation was completely abrogated by NOS inhibitors in molar excess, but inhibitors alone did not suppress phagocytosis below that of unsupplemented controls. Neither D-arginine nor glycine affected phagocytosis; the L-Arg effect was stereospecific and not related to utilization of L-Arg as an energy source. L-Arg supplementation significantly enhances bacterial phagocytosis in human neutrophils, perhaps by effects on cytoskeletal phenomena, and this appears to be mediated through NOS activity. Phagocytosis by nonspecific immune cells which intervene early in the response to sepsis is critically important, and beneficial effects of L-Arg on the clinical course of sepsis may be due at least in part to augmentation of phagocyte function.

Effect of arginine on gastrointestinal immunity during total parenteral nutrition

It has been well recognized that the prolonged use of total parenteral nutrition (TPN) leads to intestinal immunodeficiency and bacterial translocation (BT). Arginine (ARG) is known to have immunostimulatory effects. But its effects on gut immunity are unknown. This experiment was designed to evaluate the effects of arginine on gut immunity during TPN. Male Sprague Dowley rats were randomized to three groups: group I (chow) was fed rat chow and water ad libitum, group II (TPN) received a standard formula of TPN and group III (TPN-ARG) received the same formula of TPN as group II with the amino acid composition containing 0.5% arginine. With the duration of TPN, the rates of BT increased and interleukin 2 (IL-2) production decreased in TPN group. The results in TPN-ARG group were partly reversed. When TPN was administered for 2 weeks, the rate of BT decreased significantly (P < 0.05) and IL-2 production increased markedly (P < 0.01) in the TPN-ARG group compared with those in the TPN group. Our results suggest that arginine can decrease BT and increase IL-2 production in rats during prolonged TPN.

Nutritional issues in cancer management

The objective of this article was to investigate the relationship between nutrition and cancer, as it relates to the initiation, promotion, and treatment of tumor growth. English-language studies published in the last 25 years were retrieved using MEDLINE, bibliographies, and consultation with experts. MEDLINE search terms included "cancer", "malnutrition," and "nutritional support." In vitro and in vivo controlled studies addressing the impact of nutritional factors on cancer prevention and treatment were selected. Approximately 30% of cancers in the Western countries are diet-related. The presence of malignancy affects patients' nutritional status negatively, leading to increased morbidity and mortality. Standard nutritional support (both enteral and parenteral) is not always effective in significantly improving outcome in malnourished cancer patients, due to characteristic changes in host metabolism. Preliminary studies suggest that newer nutritional-pharmacologic agents may be beneficial in counteracting the derangement of host metabolism, and consequently in ameliorating cancer patients' nutritional status and outcome of malnourishment. This review suggests that dietary manipulations and nutritional-pharmacologic therapy might be highly effective adjuncts in controlling the symptoms of patients with neoplastic disease.