Kelli A. Herrlinger-Garcia

Arginine Supplementation Is Well Tolerated but Does Not Enhance Mitogen-Induced Lymphocyte Proliferation in Elderly Nursing Home Residents with Pressure Ulcers

BACKGROUNDnImmune function declines with age, increasing risk for infection and delaying wound healing. Arginine enhances immune function and healing of standardized wounds in healthy elderly persons. The purpose of this study was to determine what level of arginine supplementation was orally and metabolically tolerated and effective in enhancing immune function in elderly persons with pressure ulcers.nnnMETHODSnResidents with one or more pressure ulcers were recruited from two local nursing homes. Subjects were randomized to receive 0 g (n = 10; age, 82 +/- 3 years), 8.5 g (n = 11; 81 +/- 3 years), or 17 g (n = 11; 87 +/- 2 years) of supplemental arginine each day for 4 weeks. Oral tolerance, ie, absence of nausea, vomiting, abdominal distention, or diarrhea, was assessed daily. Metabolic tolerance was assessed weekly by evaluating serum electrolytes. Lymphocyte proliferation to phytohemagglutinin and interleukin 2 production were measured at baseline and after 4 weeks of supplementation as indicators of immune function.nnnRESULTSnSupplemental arginine significantly increased plasma arginine levels and was orally and metabolically tolerated with no complaints of abdominal distress or no clinically relevant changes in electrolyte levels among groups. Lymphocyte proliferation and interleukin 2 production were significantly different between nursing homes. When data from nursing homes were considered individually, arginine supplementation did not enhance the proliferative response. In subjects from nursing home 2 only, there was a 38% and 75% decrease (p < .05) in lymphocyte proliferation with 8.5 and 17 g of supplemental arginine, respectively. Interleukin 2 production was no different among supplementation groups.nnnCONCLUSIONSnPharmacologic doses of arginine were well tolerated but did not enhance lymphocyte proliferation or interleukin 2 production in nursing home residents with pressure ulcers. CLINICAL RELEVANCY: Enteral formulas supplemented with pharmacologic levels of arginine are frequently administered to elderly persons. This study demonstrates that the very old can tolerate these nitrogen loads if baseline renal function is normal and fluid intake is encouraged. Further research needs to be completed investigating the effect of arginine supplementation on immune function in this population before recommending arginine use.

Nutritional Formula Enhanced Immune Function and Reduced Days of Symptoms of Upper Respiratory Tract Infection in Seniors

Objectives: To assess whether an experimental nutritional formula, given as a supplement, would reduce days of symptoms of upper respiratory tract infection (URTI) and affect antibody and lymphocyte proliferative responses to influenza vaccine.

Immune Function Is Impaired With a Mini Nutritional Assessment Score Indicative of Malnutrition in Nursing Home Elders With Pressure Ulcers

BACKGROUNDnMalnutrition is prevalent in elders with pressure ulcers and is associated with increased morbidity and mortality. This study compared nutritional status, assessed by the Mini Nutrition Assessment (MNA), to immune function in nursing home elders with pressure ulcers.nnnMETHODSnNutritional status was assessed in nursing home residents (>65 years) with a stage II or more severe pressure ulcer. Subjects were classified as well nourished, at risk of malnutrition, or malnourished according to MNA score. Blood was drawn to assess whole blood mitogen-induced lymphocyte proliferation and neutrophil respiratory burst. Delayed-type hypersensitivity to 3 antigens was measured. MNA status was compared with immune parameters using the Kruskall-Wallis test.nnnRESULTSnOf the 24 subjects (23 men, 1 woman) who completed the study protocol, only 4 (17%) were classified as well nourished, whereas 7 (29%) were at risk and 13 (54%) were malnourished according to MNA score. Whole blood lymphocyte proliferation was significantly lower in the malnourished vs at risk subjects with both pokeweed (median [25th, 75th percentile], 0.6 [0.3, 0.9] vs 1.8 [1.2, 2.1] disintegrations per minute [dpm]/cell, p < .05); and concanavalin A (1.7 [0.9, 2.0] vs 2.8 [2.6, 3.9] dpm/cell, p < .05) mitogens. Neutrophil respiratory burst normalized to a young control was significantly lower in malnourished subjects vs well-nourished subjects (0.8 [0.5, 0.9] vs 1.4 [1.0, 1.7], p < .05). Total induration to 3 skin-test antigens was 13.4 +/- 4.6, 3.5 +/- 2.6, and 3.8 +/- 1.8 (mean +/- SEM) for well-nourished, at risk, and malnourished, respectively (p = .059).nnnCONCLUSIONSnImmune function is impaired with an MNA score indicative of malnutrition in nursing home elders with pressure ulcers.

Arginine Supplementation Does Not Enhance Serum Nitric Oxide Levels in Elderly Nursing Home Residents With Pressure Ulcers

The purpose of this study was to determine whether arginine supplementation enhances in vitro (neutrophil burst and mitogen-induced lymphocyte proliferation) and in vivo (delayed-type hypersensitivity [DTH] and serum nitric oxide) measures of immune function in nursing home elders with pressure ulcers. Twenty-six elders, 65 years of age or older, with one or more pressure ulcers, were randomized to receive 8.5 g of arginine or an isonitrogenous supplement for 4 weeks. Immune function studies and serum arginine, ornithine, citrulline, and nitric oxide were measured at baseline, 4 weeks postsupplementation (Week 4) and after a 6-week washout (Week 10). At Week 4, serum ornithine increased (p = .01) and arginine trended to increase (p = .055), but there was no increase in citrulline or nitric oxide with arginine supplementation. There were no differences in neutrophil burst or DTH responses between groups. Whole blood mitogen–induced proliferation decreased significantly atWeek 10 in the isonitrogenous but not in the arginine-supplemented group. There is mounting concern that arginine supplementation during an inflammatory state could be detrimental due to overwhelming nitric oxide production. A key finding of this study is that arginine supplementation did not increase serum nitric oxide levels over that observed in elders with pressure ulcers given an isonitrogenous supplement.

Oxidative stress and antioxidant capacity in smoking and nonsmoking men with HIV/acquired immunodeficiency syndrome

BACKGROUNDnPast studies document decreased levels of antioxidants and selenium and increased levels of oxidative stress in people living with HIV/acquired immunodeficiency syndrome (AIDS). Cigarette smoking is another source of oxidative stress. Excessive oxidative stress can induce HIV replication, resulting in disease progression. The purpose of this study was to determine whether subjects with HIV/AIDS who smoke cigarettes have increased oxidative stress and decreased antioxidant status compared with nonsmokers with HIV/AIDS.nnnMETHODSnThirty-one men with HIV/AIDS (adhering to highly active antiretroviral therapy for the previous 3 months) were recruited during regular visits to a Veterans Affairs Medical Center Infectious Disease Clinic in a southeastern US city. Plasma was obtained from a 1-time blood draw for this comparison study. Plasma lipid peroxide (LPO) was used as a marker of oxidative stress. Indicators of antioxidant capacity included plasma glutathione peroxidase (GPx, the functional indicator of selenium status), vitamin C, and antioxidant potential (AOP).nnnRESULTSnFifteen smokers and 10 nonsmokers with HIV/AIDS were enrolled. Median plasma LPO level was above the normal range of 0-1.3 micromol/L in both nonsmokers (2.5 [0-23.4] micromol/L, median [range]) and smokers (4.0 [0-47.5] micromol/L), but there was no difference between groups. Plasma GPx concentration was significantly lower in smokers (169 [118-295] mumol/min/L) compared with nonsmokers (197 [149-414] micromol/min/L). Vitamin C and AOP levels were not different between groups.nnnCONCLUSIONSnThis pilot study suggests that effects of smoking on oxidative stress are not additive, as no striking differences were observed in oxidative stress or antioxidant capacity between clinically stable smoking and nonsmoking men with HIV/AIDS.

Pharmacologic levels of dietary arginine in CB6F1 mice increase serum ammonia in the healthy state and serum nitrite in endotoxemia

BACKGROUNDnTherapeutic or pharmacologic doses of arginine are used to enhance blood flow and immune function despite the lack of dose-response studies and the potential for adverse effects. This study determined the optimal level of oral arginine supplementation required to elevate serum arginine concentrations yet limit adverse effects in healthy and endotoxemic mice.nnnMETHODSnMale CB6F1 mice were fed one of the following diets: The standard AIN93G (3 g arginine/100 g of protein) or this diet modified to provide 10 g, 20 g, or 30 g arginine/100 g of protein. On day 14, mice were injected with lipopolysaccharide (endotoxemic) or saline (healthy) and 4 hours later were exsanguinated.nnnRESULTSnWeight gain was reduced 50% in the group fed the 30 g arginine vs standard diet. Serum arginine, ornithine, citrulline, histidine, lysine, serine, threonine, tyrosine, and phenylalanine were greater and glutamate levels were lower in healthy supplemented mice; lipopolysaccharide treatment negated these changes. Serum ammonia concentration was 52% greater in healthy mice fed the 30 g arginine vs standard diet. Serum nitrite and urea were unaffected by supplementation in healthy mice. Serum nitrite was 37% greater in endotoxemic mice fed 30 g vs 10 g arginine, and serum urea was 27% greater in mice fed 20 g or 30 g vs 10 g arginine.nnnCONCLUSIONSnChanges in serum arginine or its metabolites were observed with all of the modified diets; however, a 30-g arginine diet was associated with an initial impairment of growth and potential adverse effects.