31P magnetic resonance spectroscopy of human liver in elderly patients: changes according to nutritional status and inflammatory state

Hepatic energy metabolism in human diabetes mellitus, obesity and non-alcoholic fatty liver disease

Alterations of hepatic mitochondrial function have been observed in states of insulin resistance and non-alcoholic fatty liver disease (NAFLD). Patients with overt type 2 diabetes mellitus (T2DM) can exhibit reduction in hepatic adenosine triphosphate (ATP) synthesis and impaired repletion of their hepatic ATP stores upon ATP depletion by fructose. Obesity and NAFLD may also associate with impaired ATP recovery after ATP-depleting challenges and augmented oxidative stress in the liver. On the other hand, patients with obesity or NAFLD can present with upregulated hepatic anaplerotic and oxidative fluxes, including β-oxidation and tricarboxylic cycle activity. The present review focuses on the methods and data on hepatic energy metabolism in various states of human insulin resistance. We propose that the liver can adapt to increased lipid exposition by greater lipid storing and oxidative capacity, resulting in increased oxidative stress, which in turn could deteriorate hepatic mitochondrial function in chronic insulin resistance and NAFLD.

(1)H and (31)P NMR studies indicate reduced bile constituents in patients with biliary obstruction and infection

Patients with extrahepatic biliary obstruction present with impairment of the normal bile flow, with jaundice and cholangitis as common complications. (1)H and (31)P NMR quantitative analysis of bile specimens from patients with extrahepatic biliary obstruction (n = 80) (with/without jaundice and cholangitis separately and together) was carried out for the chief biliary constituents to determine the relationship between biliary constituents and jaundice (serum bilirubin concentration >or=1.0 mg/dL) and cholangitis (total leucocyte count >11,000 cells/mm(3) and/or fever >38.5 degrees C with/without bile culture positivity). Compared with controls (patients without jaundice and cholangitis), median indices of the chief biliary constituents (total bile acids, cholesterol, phosphatidylcholine and inorganic phosphate) were significantly suppressed in patients with cholangitis and/or jaundice. Quantities of total bile acids, cholesterol and phosphatidylcholine correlated negatively with the quantity of bilirubin and with cholangitis, i.e. total leucocyte count. Suppression of biliary constituents correlated significantly with the severity of jaundice and cholangitis. The decrease in biliary constituents in the presence of jaundice and cholangitis is possibly the result of downregulation of the function of transporters located at the canalicular side of hepatocytes, leading to their suppressed indices in bile. This information may have implications in the examination of bile for clinical studies.

Ectopic lipids and organ function

PURPOSE OF REVIEW

To summarize recent studies that shed more light on possible mechanisms by which ectopic lipid storage affects organ function.

RECENT FINDINGS

Although ectopic lipids have been considered as biomarkers of lipotoxicity, adaptation of metabolic fluxes and of mitochondrial function seem to be more important than actual cellular fat contents in liver and muscle. Diabetic and obese humans have elevated myocardial lipid contents, which are associated with mitochondrial and contractile dysfunction and could even precede the development of heart failure. Although pancreatic fat content is negatively associated with insulin secretion, [beta]-cell triglycerides are not easily accessible to measurement in humans rendering their role for [beta]-cell function unclear. New approaches to quantify energy metabolism in various organs could help to identify novel biomarkers of organ function in humans.

SUMMARY

Dietary intake of high-caloric high-fat diets and sedentary lifestyle lead to increased storage of triglycerides not only in adipose tissue but also ectopically in other tissues. Intracellular lipid contents in skeletal muscle and liver have been related to insulin resistance and inflammatory processes. Myocardial fat is increased in heart failure, whereas pancreatic fat could relate to insulin secretion.

Proton and phosphorus-31 nuclear magnetic resonance spectroscopy of human bile in hepatopancreaticobiliary cancer

OBJECTIVE

Hepatopancreaticobiliary cancers can be difficult to diagnose. Nuclear magnetic resonance (NMR) spectroscopy provides non-invasive information on phospholipid metabolism, and previous studies of liver tissue have highlighted changes in phospholipids in malignancy. We hypothesised that in-vitro NMR spectroscopy of human bile may provide independent diagnostic indices in cancer management through an assessment of the phospholipid content.

DESIGN AND METHODS

Bile samples from 24 patients were collected at endoscopic retrograde cholangiopancreatography and from one subject at cholecystectomy. Thirteen patients had cancer: pancreatic carcinoma (eight), cholangiocarcinoma (three) and metastatic liver disease (two). The remaining 12 patients had non-malignant pathology. In-vitro proton (H) and phosphorus-31 (P) NMR spectra were obtained from all samples using an 11.7 Tesla NMR spectroscopy system.

RESULTS

Complementary information was obtained from the H and P NMR spectra. Signals were assigned to phosphatidylcholine in both H and P NMR spectra. Phosphatidylcholine levels were significantly reduced in the bile from cancer patients when compared with bile from non-cancer patients (P=0.007).

CONCLUSION

These preliminary studies suggest that H and P NMR spectroscopy of bile may be used to detect differences in phospholipid content between cancer and non-cancer patients. This may have implications for the development of novel diagnostic strategies in hepatopancreaticobiliary cancers. Further larger-scale studies are warranted.

Absolute quantification of human liver metabolite concentrations by localized in vivo 31P NMR spectroscopy in diffuse liver disease

Phosphorus-31 NMR spectroscopy using slice selection (DRESS) was used to investigate the absolute concentrations of metabolites in the human liver. Absolute concentrations provide more specific biochemical information compared to spectrum integral ratios. Nine patients with histopathologically proven diffuse liver disease and 12 healthy individuals were examined in a 1.5-T MR scanner (GE Signa LX Echospeed plus). The metabolite concentration quantification procedures included: (1) determination of optimal depth for the in vivo measurements, (2) mapping the detection coil characteristics, (3) calculation of selected slice and liver volume ratios using simple segmentation procedures and (4) spectral analysis in the time domain. The patients had significantly lower concentrations of phosphodiesters (PDE), 6.3+/-3.9 mM, and ATP-beta, 3.6+/-1.1 mM, (P<0.05) compared with the control group (10.0+/-4.2 mM and 4.2+/-0.3 mM, respectively). The concentrations of phosphomonoesters (PME) were higher in the patient group, although this was not significant. Constructing an anabolic charge (AC) based on absolute concentrations, [PME]/([PME] + [PDE]), the patients had a significantly larger AC than the control subjects, 0.29 vs. 0.16 (P<0.005). Absolute concentration measurements of phosphorus metabolites in the liver are feasible using a slice selective sequence, and the technique demonstrates significant differences between patients and healthy subjects.

Nutritional strategy in the management of heart failure in adults

The incidence of congestive heart failure (CHF) is increasing in Westernized countries, and patients with CHF experience poor quality of life (functional impairment, high hospitalization rate and high mortality). Malnutrition occurring during the course of CHF is referred to as cardiac cachexia and is associated with higher mortality independent of the severity of CHF. Cardiac cachexia involving a loss of more than 10% of lean body mass can clinically be defined as a bodyweight loss of 7.5% of previous dry bodyweight in a period longer than 6 months. The energy requirements of patients with CHF, whether cachectic or not, are not noticeably modified since the increase in resting energy expenditure is compensated by a decrease in physical activity energy expenditure. Malnutrition in CHF has been ascribed to neurohormonal alterations, i.e. anabolic/catabolic imbalance and increased cytokine release. Anorexia may occur, particularly during acute decompensation of CHF. Function is impaired in CHF, because of exertional dyspnea and changes in skeletal muscle. Decreased exercise endurance seems to be related to decreased mitochondrial oxidative capacities and atrophy of type 1 fibers, which are attributed to alteration in muscle perfusion and are partially reversible by training. Malnutrition could also impair muscle function, because of decreased muscle mass and strength associated with decreased glycolytic capacities and atrophy of type 2a and 2b fibres. With respect to the putative mechanisms of cardiac cachexia, anabolic therapy (hormones or nutrients) and anticytokine therapy have been proposed, but trials are scarce and often inconclusive. In surgical patients with CHF, perioperative (pre- and postoperative) nutritional support has been shown to be effective in reducing the mortality rate. Long term nutritional supplementation trials in patients with CHF and cachexia are thus required to establish recommendations for the nutritional management of patients with CHF.

Functional and metabolic early changes in calf muscle occurring during nutritional repletion in malnourished elderly patients

BACKGROUND

Metabolic alterations in skeletal muscle associated with malnutrition and the potential reversibility of such alterations during refeeding are not fully understood.

OBJECTIVE

We characterized early changes in muscle during refeeding in malnourished, hospitalized elderly subjects.

DESIGN

Muscle function, metabolism, and mass were evaluated in 24 clinically stable patients (11 were malnourished) by using isokinetic plantar flexor torque measurements and nuclear magnetic resonance (NMR) imaging for medial gastrocnemius mass assessment and 31P and 13C NMR spectroscopy for inorganic phosphate (Pi), phosphocreatine, and glycogen quantitation.

RESULTS

Malnourished subjects had lower muscle mass (P < 0.02) and tended to have lower strength than did control subjects. In malnourished subjects, muscle strength increased after refeeding (P < 0.01) whereas muscle mass was unchanged. The ratio of Pi to ATP was lower in malnourished than in control subjects (P < 0.001) and increased during refeeding (P < 0.01). The mean ratio of phosphocreatine to ATP was lower in malnourished than in control subjects (P < 0.01) and increased to control values after refeeding. Muscle glycogen showed a scattered distribution for malnourished subjects; the mean value did not differ significantly from that of control subjects, either at baseline or after refeeding.

CONCLUSIONS

The lower ratio of phosphocreatine to ATP in malnourished subjects could have resulted from either lower total muscle creatine or reduced oxidative capacities. High or normal glycogen associated with a low Pi-to-ATP ratio in malnourished subjects suggested preferential use of lipid over carbohydrate for energy supply, which is known to reduce muscle performance. The data suggest that normalization of muscle metabolite content after refeeding improves muscle strength in malnourished subjects.

A multi-center trial of the effects of oral nutritional supplementation in critically ill older inpatients. GAGE Group. Groupe Aquitain Geriatrique d'Evaluation

The purpose of this study was to assess the effect of nutritional supplementation on dietary intake and on pressure ulcer development in critically ill older patients. The multi-center trial involved 19 wards stratified according to specialty and recruitment for critically ill older patients; 9 wards were randomly selected for nutritional intervention (nutritional intervention group), consisting of the daily distribution of two oral supplements, with each supplement containg 200 kcal, for 15 d. Pressure ulcer incidence was prospectively recorded for grades I (erythema), II (superficial broken skin), and III (subcutaneous lesion) for 15 d. Nutritional intake was monitored by using estimates in units of quarters validated by comparison with weight measurement. There were 672 subjects older than 65 y, and 295 were in the nutritional intervention group versus 377 in the control group. The patients were similar for age, sex ratio, and C-reactive protein. In comparison with the control group, the nutritional intervention group included more patients with stroke, heart failure, and dyspnea and fewer with antecedent falls, delirium, lower limb fractures, and digestive disease. The nutritional intervention group had a lower risk of pressure ulcers according to the Norton score but was less dependent (Kuntzman score) and had a lower serum albumin level. During the trial, energy and protein intakes were higher in the nutritional intervention group (day 2: 1081 +/- 595 kcal versus 957 +/- 530 kcal, P = 0.006; 45.9 +/- 27.8 g protein versus 38.3 +/- 23.8 g protein in the control group, P < 0.001). At 15 d, the cumulative incidence of pressure ulcers was 40.6% in the nutritional intervention group versus 47.2% in the control group. The proportion of grade I cases relative to the total number of cases was 90%. Multivariate analysis, taking into account all diagnoses, potential risk factors, and the intra-ward correlation, indicated that the independent risk factors of developing a pressure ulcer during this period were: serum albumin level at baseline, for 1 g/L decrease: 1.05 (95% confidence interval: 1.02 to 1.07, P < 0.001); Kuntzmann score at baseline, for 1-point increase: 1.22 (0.32 to 4.58, P = 0.003); lower limb fracture: 2.68 (1.75 to 4.11, P < 0.001); Norton score < 10 versus > 14: 1.28 (1.01 to 1.62, P = 0.04); and belonging to the control group: 1.57 (1.03 to 2.38, P = 0.04). In conclusion, it was possible to increase the dietary intake of critically ill elderly subjects by systematic use of oral supplements. This intervention was associated with a decreased risk of pressure ulcer incidence.

Prospective audits of quality of PEM recognition and nutritional support in critically ill elderly patients

BACKGROUND AND AIMS

Undereating is a frequent concern in acute care geriatric settings and is supposed to worsen the outcomes of the underlying diseases, while the quality of nutritional support could be improved.

METHODS

Two consecutive and prospective audits (A and B) with team training over a 1 year period investigated the quality of malnutrition recognition and nutritional support and outcomes in immobilized, critically ill elderly subjects.

RESULTS

Audit A included 170 patients (86.3+/-6.1 years old) and audit B, 232 patients (86.3+/-6.3), respectively 20.6% and 31.4% of the hospitalized population. Misclassifications occurred in A in 54.0% compared to 34.05% in B (P < 0.001). 32.6% in A versus 86.9% in B adequately received oral supplements (P = 0.02). Significant risk factors for the adverse outcomes in the combined two audits were: dementia (RR: 1.8, 95%CI: 1.0 to 3.0, P= 0.04) and dehydration (RR: 2.0, 95%CI:1.0 to 4.1, P= 0.05) for pressure ulcer incidence; stroke (RR: 8.8, 95%CI: 4.8 to 16.0, P < 0.001) for pressure ulcer prevalence at discharge; neoplasms (RR: 1.1, 95%CI: 1.0 to 1.2, P = 0.02) for nosocomial infections; bladder indwelling for urinary tract infections (RR: 4.8, 95%CI: 2.9 to 7.7, P<< 0.001); swallowing problems for pulmonary infections (RR: 5.4, 95%CI: 2.8 to 10.5, P < 0.001); venous indwelling for septicaemia (RR: 5.4, 95%CI: 1.3 to 23. 3, P= 0.02). However, after adjustment on significant risk factors, the outcome rate was similar in audit B: death rate: A (15.6%), B (14.2%); length of stay: A (17.3+/-10.4 days), B (17.4+/-10.0); pressure ulcer incidence: A (26.4%), B (20.2%), (83% were erythema); pressure ulcer prevalence at discharge: A (14.7%), B (10.3%), (40% were erythema); nosocomial infections: A (26.4%), B (19.0%).

CONCLUSION

The improvement of malnutrition recognition and nutritional support was not followed by a perceptible decrease in adverse outcome rate, this latter being mainly related to the underlying conditions of these critically ill elderly patients.