Adaptive response of pancreatic and intestinal function to nutritional intake in the aged

Understanding pancreatic exocrine insufficiency and replacement therapy in pancreatic cancer

Pancreatic exocrine insufficiency (PEI) is highly prevalent in patients with pancreatic cancer, and has substantial implications for quality of life and survival. Post resection, PEI is associated with increased post-operative complications, longer hospital stays and higher costs. Treatment with pancreatic enzyme replacement therapy (PERT) improves quality of life and confers significant survival advantages. Despite this many patients with pancreatic cancer do not currently receive PERT. The nutritional consequences of PEI are extensive and even more relevant in the elderly owing to age related gastrointestinal tract and pancreatic changes that predispose to malnutrition.

Postprandial Cholecystokinin Secretion in Elderly with Protein-Energy Undernutrition

OBJECTIVE

Malnutrition is currently observed in aged people, and cholecystokinin is an important peripheral satiety signal. The aim of this study was to examine the effect of aging and protein-energy malnutrition on postprandial cholecystokinin (CCK) release.

DESIGN

Non-randomized, cross-sectional comparison by age group.

SETTING

Gastroenterology section of a teaching hospital.

PARTICIPANTS

Twenty-one human volunteers divided into three groups: young healthy subjects (Group 1: mean 29 years, n = 7), aged healthy subjects (Group 2, mean 80 years, n = 7), and aged subjects with an important degree of malnutrition (Group 3, mean 84.6 years, n = 7).

INTERVENTION

Each subject ingested a standardized liquid meal after an overnight fast.

MAIN OUTCOME MEASURES

Plasma cholecystokinin was measured using a sensitive bioassay before and after the ingestion of the liquid meal.

RESULTS

Basal cholecystokinin levels were similar (0.9 to 1 pM equivalent CCK-8) in the three groups. Postprandial levels were significantly increased over basal (P less than 0.05). The maximal cholecystokinin value was lower in Group 1 (3.5 +/- 0.8 pM equivalent CCK-8) and Group 2 (3.3 +/- 0.77 pM equivalent CCK-8) than in Group 3 (8.3 +/- 2 pM equivalent CCK-8) (P less than 0.05). Integrated plasma cholecystokinin was also similar in Group 1 (171 +/- 38 pM.60 min), (P less than 0.05).

CONCLUSION

The increase of postprandial maximal levels of cholecystokinin is more related to malnutrition than to aging.

Consumption of diets containing raw soya beans (Glycine max), kidney beans (Phaseolus vulgaris), cowpeas (Vigna unguiculata) or lupin seeds (Lupinus angustifolius) by rats for up to 700 days: effect on body composition and organ weights

Feeding trials have been done with rats to assess the effects of long-term (700 d) consumption of diets based on raw cowpeas (Vigna unguiculata; moderate Bowman–Birk inhibitor content, low lectin content), lupin seeds (Lupinus angustifolius; low lectin and protease inhibitor content) or soya beans (Glycine max; high Kunitz inhibitor content, moderate Bowman–Birk inhibitor content, moderate lectin content) or diets containing low levels of raw kidney bean (Phaseolus vulgaris; high lectin content, low Bowman–Birk inhibitor content) on body weight and composition and organ weights. All the legume-based diets reduced feed conversion efficiency and growth rates during the initial 250 d. However, after 250 d the weight gains by rats given legume-based diets were similar to those of controls given the same daily feed intake. Long-term consumption of diets containing low levels of kidney bean significantly altered body composition of rats. The levels of lipid in the body were significantly reduced. As a result, carcasses of these rats contained a higher proportion of muscle/protein than did controls. Small-intestine relative weight was increased by short- and long-term consumption of the kidney-bean-based diet. However, the increase in relative pancreatic weight observed at 30d did not persist long term. None of the other legume-based diets caused any significant changes in body composition. However, long-term exposure to a soya-bean- or cowpea-based diet induced an extensive increase in the relative and absolute weights of the pancreas and caused an increase in the incidence of macroscopic pancreatic nodules and possibly pancreatic neoplasia. Long-term consumption of the cowpea-, kidney-bean-, lupin-seed- or soya-bean-based diets by rats resulted in a significant increase in the relative weight of the caecum and colon.

Intestinal malabsorption in the elderly

BACKGROUND

Intestinal malabsorption in the elderly is infrequent, and clinical features are muted so that the diagnosis is often missed. Physiologic changes with aging are restricted to altered absorption of calcium and perhaps zinc and magnesium; however, achlorhydria can lead to impaired absorption of vitamin B(12), folic acid, and calcium.

METHODS AND RESULTS

Small bowel bacterial overgrowth occurs more commonly in elderly than in younger patients, accompanying gastric hypochlorhydria, altered intestinal motor activity, or diseases such as Parkinson's disease. Changes in pancreatic anatomy and secretion occur but are insufficient to produce macronutrient malabsorption. In addition to pancreatic cancer and pancreatic stones, older patients may present with severe pancreatic insufficiency of unknown etiology. Celiac disease is recognized as very common at all ages and may not become evident until late in life. Manifestations of celiac disease in the elderly are occult and the diagnosis often is not considered until serologic tests are performed and confirmed by upper small intestinal biopsy. Associated intestinal lymphoma, esophageal carcinoma, intestinal pseudo-obstruction, and splenic atrophy may be more common in the elderly. Treatment of older patients with celiac disease with a gluten-free diet may be difficult, and intensive vitamin and micronutrient replacement is mandatory. A pragmatic approach to the evaluation of malabsorption in elderly patients is discussed.

Effect of long-term high-fat feeding on the expression of pancreatic lipases and adipose tissue uncoupling proteins in mice

INTRODUCTION

A diet containing a high amount of fat has been shown, in short-term studies, to increase the expression of pancreatic lipase and colipase.

AIM

To investigate the effects of long-term high-fat-feeding (113 days) on the mRNA expression of pancreatic lipase, colipase, pancreatic lipase-related proteins (1 and 2), and uncoupling proteins during the development of obesity and glucose intolerance.

METHODOLOGY

Mice were fed either a high-fat or standard diet and killed after 3, 13, 57, and 113 days. Brown and white adipose tissue and pancreas were collected for mRNA extraction [corrected].

RESULTS

The high-fat-fed mice became obese and glucose-intolerant by 113 days. The high-fat diet increased lipase (p < 0.05) expression initially. At the end of the experiment, the lipase levels had decreased to the level of the control. Colipase levels did not change during the first 57 days of high-fat feeding but decreased below control levels by 113 days (p < 0.05). The high-fat diet increased brown adipose tissue uncoupling protein 1 (UCP1)(p < 0.005) expression but not the expression of uncoupling protein 2.

CONCLUSION

Long-term high-fat feeding, leading to glucose intolerance, occurs with a simultaneous decrease in the mRNA expression of pancreatic lipase and colipase and an increase in UCP1 expression.

Pancreatic disease in the elderly

Pancreatic diseases occur in patients of every age. Older individuals suffer more often from gallstone related acute pancreatitis, ischaemic and idiopathic acute pancreatitis, whereas alcohol-induced acute pancreatitis occurs only in a minority of cases. Similarly, alcohol-related chronic pancreatitis in elderly people is rare and late-onset idiopathic chronic pancreatitis is the most common form of the disease. This form of chronic pancreatitis is characterized by faster progression to endocrine and exocrine pancreatic insufficiency and less severe pain compared to the clinical picture found in younger patients. Ductal pancreatic adenocarcinomas, which are responsible for more than 90% of exocrine pancreatic tumours, are typically a disease of the elderly patient. Today pancreatic resection still offers the only hope for cure and also can be performed safely in elderly patients. Age, by itself, is not a reason for withholding surgical intervention from an individual patient. Today, denial of pancreatic resection is much more likely to be based on severe co-morbidity.

A pancreatic extract-enriched diet improves the nutritional status of aged rats

Correction of the malnourished state, particularly common and severe in elderly people, is often unsuccessful. To improve the efficiency of realimentation, we evaluated the nutritional effect of a pancreatic extract (PE)-enriched diet in malnourished aged rats. Sprague-Dawley male rats were randomly assigned to 6 groups as follows: 1 group of control rats had free access to the diet for 12 wk (C group) and 5 groups were 50% food restricted for the same period. One food-restricted group was then killed (R group) and the 4 remaining groups were refed for 1 wk using a standard diet enriched either with two different doses of a pancreatic extract (2.4 or 4.8 g/d in PE1 and PE2 groups, respectively) or with an isonitrogenous casein hydrolysate (CH1 and CH2 groups, respectively). Profound alterations induced by food restriction (FR) were moderately corrected by refeeding, except nitrogen balance, which was reestablished in rats refed all diets (P: < 0.01 vs. R). Supplementation of the food ration with a pancreatic extract clearly improved recovery. Indeed, body weight gain, both jejunal and ileal trophicity [jejunum: total height, PE2: 849 +/- 45 microm vs. CH2: 768 +/- 17 microm (P: < 0.05); protein content, PE2: 69.9 +/- 5.7 mg vs. CH2: 56.4 +/- 4.8 mg (P: < 0.01)] and nonspecific immune response in terms of H2O2 production by polymorphonuclear neutrophils and tumor necrosis factor alpha (TNF-alpha) by macrophages (PE2, 20.7 +/- 4.7 vs. CH2, 8.7 +/- 2.3, P: < 0.05) were improved in rats fed PE2. A pancreatic extract could improve the efficiency of realimentation in malnourished aged rats.

Severe dietary restriction initiated in aged rats: evidence for poor adaptation in terms of protein metabolism and intestinal functions

BACKGROUND

Protein energy malnutrition is a common finding in elderly people, increasing morbidity and mortality in aged inpatients. Investigations need to be developed to counteract malnutrition-induced alterations early and to avoid potential irreversible lesions. The aim of this experimental study was to evaluate time-response to severe dietary restriction (DR) initiated in aged rats in terms of protein metabolism and digestive trophicity.

MATERIALS AND METHODS

After the acclimatization period, 22-month-old male rats were randomized into six groups: three control groups, fed ad libitum for 3, 6 or 12 weeks with a standard diet and three corresponding dietary-restricted groups fed for the same periods with only 50% of the spontaneous intake. Intestinal mucosa, liver and skeletal muscles (soleus, extensor digitorum longus and tibialis anterior muscle) were removed when the rats were killed.

RESULTS

DR induced dramatic body weight loss (up to 50% of initial body weight after 12 weeks DR). Protein metabolism was affected in terms of nitrogen balance (P < 0.01) and protein content, in particular at the splanchnic level. Morphometrically, the intestine structure was altered after 12 weeks of DR (P < 0.01), and this atrophy was correlated with malabsorption of mannitol (P < 0. 01). Ileal hydrolase activities were decreased throughout the 12 weeks of DR.

CONCLUSIONS

Aged rats clearly exhibit a defect of adaptation to long-term DR initiated at an advanced age. Severe DR leads to malnutrition, which becomes of major importance after 12 weeks, in particular at the intestine level. Hence, application of these experimental results to elderly, malnourished people may contribute to a better knowledge of denutrition-induced disorders.

Supplementation of oral nutrition with pancreatic enzymes improves the nutritional status of aged endotoxemic rats

Malnutrition is a common problem in elderly people. The association of malnutrition and physical illness or injury leads to both localized and general complications. In particular, impairment of the adaptive response of pancreatic function to undernutrition and refeeding may adversely affect nutritional status and elicit morbidity and mortality. Aged rats (24 mo old) were treated with lipopolysaccharide (LPS) from E. Coli (3 mg/kg body weight). Six days later, survivors were randomized to receive, for 7 days, an oral chow diet enriched with either a pancreatic extract (PE) (2.4 mg/day) or an isonitrogenous supply of casein (CAS). Endotoxemia induced a catabolic state, with a body weight loss of 7.6 +/- 1.1% on day two after LPS treatment. Mean food intake from day 6 to day 13 was similar in LPS-PE and LPS-CAS groups (19.0 +/- 5.6 versus 19.7 +/- 6.9 g). The metabolic response varied according to the type of muscle studied. In fast (white) muscle, the protein content and the glutamine pool remained markedly depleted in endotoxemic rats receiving casein supplementation. In contrast, enrichment of nutrition with PE significantly limited the LPS-induced muscle wasting and increased the muscle glutamine content. As in previous observations, no significant change occurred in slow (red) muscle. These results could indicate that PE supplementation counteracts pancreatic deficiency caused by aging and worsened by stress and this, in turn, could improve the efficiency of nutrition, to support the hypermetabolism of aged injured rats.

Modulation of proliferation, second messenger levels, and morphotype expression of the rat intestinal epithelial cell line IEC-6 by fermented milk

Trophic effects of milk fermented with Lactobacillus helveticus, Lactobacillus paracasei ssp. paracasei, Bifidobacterium sp., or the combination of Lactobacillus bulgaricus and Streptococcus thermophilus (yogurt) were studied on the IEC-6 intestinal epithelial cell line. Incorporation of [methyl-3H]thymidine, mitochondrial dehydrogenase activities, cyclic AMP production, and differentiation of levels of the IEC-6 strain were evaluated between the 15th and 30th passage in culture. All fermented and unfermented milks enhanced trophic responses of IEC-6 cells in a dose-dependent manner. Compared with the corresponding milks, supernatant fractions were more effective in stimulating mitochondrial dehydrogenase response. Fermented milk supernatants were also more effective than the corresponding unfermented fractions. Increases in DNA synthesis and cyclic AMP confirmed the activation observed with mitochondrial dehydrogenase. Yogurt induced the more trophic response with an increased number of the more differentiated cell morphotype. Fermentation with L. casei also demonstrated an important trophic adaptation of IEC-6 cells. Milk processing by lactic acid bacteria enhanced trophic and proliferation responses of intestinal epithelial cell line IEC-6. These results suggested that IEC-6 cells could represent an accurate and easy in vitro model for testing the trophic quality of various nutrients and for an optimization of physiological digestive functions.

Pancreatic enlargement is evident in rats fed diets containing raw soybeans (Glycine max) or cowpeas (Vigna unguiculata) for 800 days but not in those fed diets based on kidney beans (Phaseolus vulgaris) or lupinseed (Lupinus angustifolius)

Pancreatic weights and composition were studied with rats fed diets containing raw legume seeds for up to 800 d. Rapid pancreatic enlargement was induced by dietary soybeans (Glycine max) (high Kunitz and Bowman-Birk trypsin inhibitor contents, moderate lectin content) during the initial 150 d. Over the next 200 d the rate of pancreatic growth was similar to that in controls. After 350 d a second period of rapid pancreatic growth occurred. Macroscopic pancreatic nodules were evident in a number of rats fed soybeans for 500 d or more. A similar pattern of pancreatic growth was observed in rats fed dietary cowpeas (Vigna unguiculata) (high Bowman-Birk inhibitor content, low lectin content). Extensive pancreatic growth was also found in young rats fed moderate dietary levels of kidney beans (Phaseolus vulgaris) (low Bowman-Birk inhibitor content, high lectin content). However, the trophic effects diminished with time, and from 100 d onwards, little enlargement was evident. Consumption of a lupinseed (Lupinus angustifolius) diet (low trypsin inhibitor, low lectin content) did not cause pancreatic enlargement. The initial pancreatic growth induced by dietary soybeans seemed to be due to the lectins and trypsin inhibitors, whereas the second period of pancreatic growth was possibly due primarily to the trypsin inhibitors.

Nutrition support for the elderly

The increasing size and longevity of the geriatric patient population dictates that all health care practitioners become more cognizant of the unique requirements for nutritional assessment and support of the elderly. This review summarizes recent advances in the understanding of the nutrition support needs of the old and oldest-old patients requiring enteral or parenteral feeding. When a nutrition support formula individualized for the geriatric patient is being developed, there is a fine line between excess and deficit, requiring the involvement of the entire support team in monitoring the success of feeding. Indications for choosing enteral or parenteral feeding are considered excessively invasive by some and necessarily "heroic" by others. The patient and his or her family should be part of the decision-making process.