Role of the cellular hydration state for cellular function: physiological and pathophysiological aspects

Hydration in advanced cancer: can bioelectrical impedance analysis improve the evidence base? A systematic review of the literature

CONTEXT

Decisions surrounding the administration of clinically assisted hydration to patients dying of cancer can be challenging because of the limited understanding of hydration in advanced cancer and a lack of evidence to guide health care professionals. Bioelectrical impedance analysis (BIA) has been used to assess hydration in various patient groupings, but evidence for its use in advanced cancer is limited.

OBJECTIVES

To critically appraise existing methods of hydration status assessment in advanced cancer and review the potential for BIA to assess hydration in advanced cancer.

METHODS

Searches were carried out in four electronic databases. A hand search of selected peer-reviewed journals and conference abstracts also was conducted. Studies reporting (de)hydration assessment (physical examination, biochemical measures, symptom assessment, and BIA) in patients with advanced cancer were included.

RESULTS

The results highlight how clinical examination and biochemical tests are standard methods of assessing hydration, but limitations exist with these methods in advanced cancer. Furthermore, there is disagreement over the evidence for some commonly associated symptoms with dehydration in cancer. Although there are limitations with using BIA alone to assess hydration in advanced cancer, analysis of BIA raw measurements through the method of bioelectrical impedance vector analysis may have a role in this population.

CONCLUSION

The benefits and burdens of providing clinically assisted hydration to patients dying of cancer are unclear. Bioelectrical impedance vector analysis shows promise as a hydration assessment tool but requires further study in advanced cancer. Innovative methodologies for research are required to add to the evidence base and ultimately improve the care for the dying.

Bioelectrical Impedance Phase Angle Changes During Hydration and Prognosis in Advanced Cancer

Introduction. We wished to determine bioelectrical impedance (BIA) correlates before hydration or changes during hydration and determine if these changes were prognostically important.

Methods and Materials. Fifty eligible patients underwent BIA measurements 3 consecutive days. Laboratory studies (electrolytes, creatinine, and hemoglobin) on day 1; weights and vital signs were recorded. Kaplan-Meier survival estimates were made at 30 and 60 days. Hazard ratios (HRs) based on Cox proportional hazards model were calculated.

Results. Weight loss was associated with shorter survival. A higher phase angle (PA) on day 1 predicted longer survival. Increased PA during hydration predicted shorter survival: increased weight during hydration predicted longer survival.

Discussion. Higher phase angle before hydration predicts poorer survival and, paradoxically, an increase in phase angle during hydration predicted poorer survival and preexisting intracellular dehydration, cachexia, or poor membrane function. Conclusions. Phase angle and weight during hydration predict survival in cancer.

Manganese induces cell swelling in cultured astrocytes

Manganese in excess is neurotoxic and causes a CNS disorder that resembles Parkinson's disease (manganism). Manganese highly accumulates in astrocytes, which renders these cells more vulnerable to its toxicity. Consistent with this vulnerability, manganese has been shown to cause histopathological changes in astrocytes (Alzheimer type II change), generates oxidative stress and bring about mitochondrial dysfunction, including the induction of the mitochondrial permeability transition (mPT) in astrocytes. In addition to manganism, increased brain levels of manganese have been found in hepatic encephalopathy, a chronic neurological condition associated with liver dysfunction, wherein Alzheimer type II astrocytic changes are also observed. As low-grade brain edema, possibly secondary to astrocyte swelling, has been reported in hepatic encephalopathy, we hypothesized that manganese may contribute to such edema. We therefore exposed cultured astrocytes to manganese (Mn(3+)) acetate (25 and 50microM) for different time periods and examined for changes in cell volume. Manganese dose-dependently induced astrocyte swelling; such swelling was first observed at 12h (28%), which further increased (54%) at later time points (24-48h). Pretreatment of astrocyte cultures with antioxidants, including vitamin E, the spin trapping agent PBN, and the iron-chelating agent desferroximine, as well as the nitric oxide synthase inhibitor l-NAME, all significantly blocked (50-80%) astrocyte swelling caused by manganese, suggesting that oxidative/nitrosative stress is involved in the mechanism of such swelling. Cyclosporin A, an inhibitor of mPT also blocked (90%) manganese-induced astrocyte swelling. The data indicate that manganese exposure results in astrocyte swelling and such swelling, at least in part, may be caused by oxidative stress and/or mPT. Astrocyte swelling by manganese may represent an important aspect of manganese neurotoxicity, and may be a factor in low-grade brain edema associated with chronic hepatic encephalopathy.

Proton magnetic resonance spectroscopy (1H-MRS) findings for the brain in patients with liver cirrhosis reflect the hepatic functional reserve

OBJECTIVE

Proton magnetic resonance spectroscopy (1H-MRS) has been used to assess the metabolic changes in the brain in patients with liver cirrhosis. Decreased myo-inositol and increased glutamine levels were noted to be the most sensitive spectroscopic markers for cirrhotic patients with hepatic encephalopathy (HE). The purpose of this study was to assess how the abnormalities seen on the 1H-MRS of the brain in patients with liver cirrhosis are related to clinical and laboratory parameters.

METHODS

In a prospective study, localized 1H-MRS was performed in the basal ganglia and parietal white matter regions in liver cirrhosis patients with (n = 48) and without (n = 52) HE and chronic hepatitis (CH) (n = 15), and in normal controls (n = 20).

RESULTS

Among cirrhotic patients, the myo-inositol levels were significantly lower (p < 0.01) and the glutamine levels were higher (p < 0.05) for patients with HE than for those without HE. The myo-inositol and glutamine levels, respectively, were inversely (r = -0.50; p < 0.001) and linearly (r = 0.50; p < 0.001) related to the Child-Pugh score. However, by subgroup analysis of Child-Pugh class C patients, there were no significant differences in the myo-inositol and glutamine levels between cirrhotic patients with (n = 40) and without HE (n = 24). A follow-up study of eight cirrhotic patients with HE showed no significant differences in the myo-inositol and glutamine levels after clinical improvement of HE.

CONCLUSIONS

The abnormalities seen on the 1H-MRS of the brain of patients with liver cirrhosis are not likely to reflect the severity of HE or acute alteration in the level of consciousness. Rather, we believe they represent the chronic metabolic derangement of the brain associated with hepatic functional reserve.