Lithium transport across red cell membrane: a cell membrane abnormality in manic-depressive illness

FROZEN! Intracellular multi-electrolyte analysis measures millimolar lithium in mammalian cells

Lithium salts are commonly used as medication for Bipolar Disorder (BD) and depression. However, there are limited methods to quantify intracellular lithium. Most methods to analyze intracellular electrolytes require tedious sample processing, specialized and often expensive machinery, sometimes involving harmful chemicals, and a bulk amount of the sample. In this work, we report a novel method (FROZEN!) based on cell isolation (from the surrounding medium) through rapid de-ionized water cleaning, followed by flash freezing for preservation. SKOV3 cells were cultured in normal medium and a medium containing 1.0 mM lithium. Lithium and other intracellular electrolytes in the isolated and preserved cells were simultaneously analyzed with laser-induced breakdown spectroscopy (LIBS) and X-ray fluorescence spectroscopy (XRF). Key electrolytes such as sodium, potassium, and magnesium, along with lithium, were detectable at the single-cell level. We found that cells cultured in the lithium medium have an intracellular lithium concentration of 0.5 mM. Concurrently, the intracellular concentrations of other positively charged electrolytes (sodium, potassium, and magnesium) were reduced by the presence of lithium. FROZEN! will greatly facilitate research in intracellular electrolyte balance during drug treatment, or other physiological stresses. In particular, the cell isolation and preservation steps can be easily performed by many laboratories worldwide, after which the samples are sent to an analytical laboratory for electrolyte analysis.

Amino acid transport in human red blood cells

Rafaelsen (1) has proposed a membrane transport model involving transport function deficiencies in affective disorders. The deficiencies of transport concern a group pump as well as a specific pump in the cell membrane. As peripheral blood cells are important for the study of basic features essential to biological transport functions and have been suggested as models for membrane mechanisms in the CNS, a series of studies was undertaken to characterize amino acid transport in the human red blood cell (h-RBC). Five different transport systems were identified by kinetic analysis and studies of inhibition and sodium dependence of transport: the L-, T-, Ly-, ASC- and Gly-system. The T-system which appeared specific to L-tryptophan transport has not been identified in other cells. The L-system for large neutral amino acids and the T-system correspond to the group and specific pump, respectively, of the model of Rafaelsen. The importance of the h-RBC as a tool of biological psychiatry is discussed.

Metabolic depression in hibernation and major depression: an explanatory theory and an animal model of depression

Metabolic depression, an adaptive biological process for energy preservation, is responsible for torpor, hibernation and estivation. We propose that a form of metabolic depression, and not mitochondrial dysfunction, is the process underlying the observed hypometabolism, state-dependent neurobiological changes and vegetative symptoms of major depression in humans. The process of metabolic depression is reactivated via differential gene expression in response to perceived adverse stimuli in predisposed persons. Behavior inhibition by temperament, anxiety disorders, genetic vulnerabilities, and early traumatic experiences predispose persons to depression. The proposed theory is supported by similarities in the presentation and neurobiology of hibernation in bears and major depression and explains the yet unexplained neurobiological changes of depression. Although, gene expression is suppressed in other hibernators by deep hypothermia, bears were chosen because they hibernate with mild hypothermia. Pre-hibernation in bears and major depression with atypical features are both characterized by fat storage through overeating, oversleeping, and decreased mobility. Hibernation in bears and major depression with melancholic features are characterized by withdrawal from the environment, lack of energy, loss of weight from not eating and burning stored fat, changes in sleep pattern, and the following similar neurobiological findings: reversible subclinical hypothyroidism; increased concentration of serum cortisol; acute phase protein response; low respiratory quotient; oxidative stress response; decreased neurotransmitter levels; and changes in cyclic-adenosine monophosphate-binding activity. Signaling systems associated with protein phosphorylation, transcription factors, and gene expression are responsible for the metabolic depression process during pre-hibernation and hibernation. Antidepressants and mood stabilizers interfere with the hibernation process and produce their therapeutic effects by normalizing the fluctuation of activities in the different signaling systems, which are down-regulated during hibernation and depression and up-regulated during exodus from hibernation and the hypomanic or manic phase of mood disorders. The ways individuals cognitively perceive, understand, communicate, and react to the vegetative symptoms of depression, from downregulation in energy production, and in the absence of known medical causes, produce the other characteristics of depression including guilt, helplessness, hopelessness, suicidal phenomena, agitation, panic attacks, psychotic symptoms, and sudden switch to hypomanic or manic episodes. The presence of one or more of these characteristics depends on the person's neuropsychological function, its social status between the others, and the other's response to the person. Neurobiological changes associated with metabolic depression during entrance, maintenance, and exodus from hibernation in bears is suggested as a natural animal model of human depression and mood disorders.

Increased oxidative stress and decreased activities of Ca(2+)/Mg(2+)-ATPase and Na(+)/K(+)-ATPase in the red blood cells of the hibernating black bear

During hibernation, animals undergo metabolic changes that result in reduced utilization of glucose and oxygen. Fat is known to be the preferential source of energy for hibernating animals. Malonyldialdehyde (MDA) is an end product of fatty acid oxidation, and is generally used as an index of lipid peroxidation. We report here that peroxidation of lipids is increased in the plasma and in the membranes of red blood cells in black bears during hibernation. The plasma MDA content was about four fold higher during hibernation as compared to that during the active, non-hibernating state (P < 0.0001). Similarly, MDA content of erythrocyte membranes was significantly increased during hibernation (P < 0.025). The activity of Ca(2+)/Mg(2+)-ATPase in the erythrocyte membrane was significantly decreased in the hibernating state as compared to the active state. Na(+)/K(+)-ATPase activity was also decreased, though not significant, during hibernation. These results suggest that during hibernation, the bears are under increased oxidative stress, and have reduced activities of membrane-bound enzymes such as Ca(2+)/Mg(2+)-ATPase and Na(+)/K(+)-ATPase. These changes can be considered part of the adaptive for survival process of metabolic depression.

Lithium toxicity: when is hemodialysis necessary?

A case of severe lithium intoxication is presented in which the function of the lithium pump was monitored, and was found to improve as the signs of lithium toxicity abated. The status of the lithium pump may provide an index of the severity of lithium intoxication. Since the lithium pump regulates the extrusion of lithium from the intracellular to the extracellular space, it is argued that the activity of the lithium pump is an index of the severity of lithium intoxication and crucial to the process of detoxification.

Lithium distribution in mania: single-dose pharmacokinetics and sympathoadrenal function

We examined lithium distribution after a single dose of 25 mEq in 14 drug-free manic patients. Lithium concentrations were measured in plasma, red blood cells, and urine. Maximum concentrations of lithium, times at which they were attained, and influx and efflux rate constants for extracellular fluid, red blood cell, and muscle-like compartments were estimated using a three-compartment pharmacokinetic model. Tissue lithium concentrations may continue to increase for hours after plasma lithium concentrations have peaked. Rate constants for absorption, excretion, and influx and efflux for the tissue compartments were similar to those previously reported for normal subjects. Rate constants for transport into and out of the tissue compartments correlated negatively with norepinephrine or epinephrine excretion and positively with the plasma/red cell Na+ gradient. Rate constants for efflux from red blood cell and muscle compartments correlated with measures of adrenocortical function and were higher in dexamethasone nonsuppressors than in suppressors. These data show that distribution of lithium may be related to sympathodrenal activity and Na+ distribution in manic patients.

EEG sleep, lithium transport, dexamethasone suppression, and monoamine oxidase activity in borderline personality disorder

Twenty-one patients who met DSM-III criteria for borderline personality disorder (BPD) and also scored at least 7 on the Diagnostic Interview for Borderlines (DIB) were assessed on four biological markers: electroencephalographic (EEG) sleep, in vitro lithium ratio, platelet monoamine oxidase (MAO), and dexamethasone suppression test (DST). REM latency averaged 58.66 (SD 14.39); platelet MAO averaged 21.74 (SD 10.33); and lithium ratio was 0.357 (SD 0.139) in the BPD patients. All of those values were significantly abnormal. Many patients had abnormalities on three or four measures. These patients in general had multiple Axis I diagnoses from the Diagnostic Interview Schedule (DIS), and these Axis I diagnoses tended to produce patient clusters. Patients with a DIS diagnosis of schizophrenia, mania, hypomania, or schizoaffective mania had elevated lithium, low MAO, and normal EEG sleep, while those patients with coexisting major depression tended to have short rapid eye movement (REM) latency, high REM density, and normal MAO and lithium ratio. Only two patients were nonsuppressors on the DST, confirming recent reports of normal DST results in personality disorders.

A review of the biochemical and neuropharmacological actions of lithium

The pharmacological actions central to the therapeutic effects of lithium have not yet been established, despite almost 40 years of clinical use and scientific investigation. We review the biochemical and neuropharmacological data relating to this problem and attempt to identify profitable areas for further research.

The effect of lithium on the membrane molecular dynamics of normal human erythrocytes

Erythrocytes from normal adults with no personal or family history of bipolar affective disorder were analyzed by fluorescence spectroscopy to determine what effect, if any, acute in vitro incubation with lithium had on erythrocyte membrane dynamics. The effects on erythrocyte membrane molecular dynamics of varying concentrations of Li2CO3 (0.25-2.0 meq/liter), varying incubation temperatures (25-40 degrees C), and varying incubation times (5-185 min) were investigated. Following incubation with Li2CO3, the erythrocytes were labeled with either 4-phenylspiro-[furan-2(3H),--1'phthalan]--3,3'-dione (fluorescamine), which binds to membrane surface primary amines, or 12(9)anthroyl stearate [12(9)AS], which inserts deep in the membrane hydrocarbon core. The membrane molecular dynamics were then determined by fluorescence anisotropy measurements. These studies demonstrate that clinically relevant concentrations of Li+ incubated with intact normal human erythrocytes significantly alters molecular dynamics on the erythrocyte membrane surface, with less striking changes in the hydrocarbon core. A possible interpretation of these findings is that hydrated Li+ alters the electrostatic interaction of membrane surface molecules, as well as the surrounding solvent (water) structure, with a resultant increase in the molecular motion of these molecules. Alterations in membrane receptor motion could potentially alter receptor functional activity. If similar motional alterations were to occur in the interior of a membrane channel, such as an ionophore, the functional activity of the channel could also be potentially altered. These findings provide additional insight into possible biological actions of Li+, as well as potential molecular alterations in bipolar affective disorder erythrocytes.

Lithium distribution in mania: plasma and red blood cell lithium, clinical state, and monoamine metabolites during lithium treatment

We examined red blood cell (RBC) and plasma lithium concentrations and RBC/plasma lithium ratios in 14 manic patients during lithium treatment as part of the National Institute of Mental Health's Collaborative Program on the Psychobiology of Depression, Biological Studies. All of the lithium measures increased during treatment, especially RBC lithium. There were positive correlations between the RBC lithium concentration and the RBC/plasma lithium ratio and their maximal values in a single-dose pharmacokinetic experiment before treatment. After 5 and 16 days of treatment, patients with good subsequent outcome had higher RBC/plasma lithium ratios than did patients with poor outcome. Early in treatment, there was a negative correlation between lithium concentrations and severity of mania. During treatment, there was a negative correlation between RBC lithium and urinary MHPG excretion. There was a positive correlation between RBC or plasma lithium during the first few days of treatment and subsequent reduction in norepinephrine excretion during treatment. At 3 weeks, there were negative correlations between reductions in catecholamine measures and lithium concentrations. These data suggest that there are changes in the sensitivity of behavior and catecholamine function to lithium during treatment. RBC concentrations of lithium appear to be a potentially useful indicator of its behavioral and neurochemical effects.

Clinical methods in psychiatric genetics. II. The high risk approach

The study of individuals at "high" risk for developing psychiatric disorders is useful in confirming that a biological trait marker identified in patient populations is also present in genetically susceptible individuals who have never been ill, and predicts the future onset of illness. We outline a systematic method for deciding which variables to choose and how many individuals are required in order for a study to have sufficient power. We demonstrate how these decisions depend on the assumptions that can be made with regard to the mode of inheritance of the biological trait, the relationship of the biological trait to illness, and the magnitude of the mean difference observed between patients and controls. We also quantify the increased power of studying offspring of two affected parents rather than offspring of one affected parent.

Risk research in affective disorders and alcoholism: epidemiological surveys and trait markers

Traditional designs in risk research have been in the form of epidemiologic surveys aimed at assessing a genetic contribution or search for broader indicators of vulnerability, resulting from the interaction of both nature and nurture. Recently, an interest in biological markers has resulted in the search for possible trait markers identifying more specifically, individuals with a life-long risk for an illness that may be expressed or not. The contributions, limitations and evolution of these strategies are reviewed in the syndromes of affective disorders and alcoholism. Recommendations include the use of biotypes rather than phenomenotypes for the diagnosis of the index case. Current promising approaches include the study of pedigrees biased towards a particular variable, a discriminant analysis of the variation in expressivity of the syndrome and the genetic linkage studies. While there is so far no established trait marker, research strategies are emerging and withstanding the test of time. The present technological explosion will undoubtedly further our understanding of risk factors.

NMR studies of combined lanthanide shift and relaxation agents for differential characterization of 23Na in a two-compartment model system

Spin relaxation and chemical shifts by lanthanide chelate complexes are used to distinguish 23Na signals in a simulated two-compartment model. Both effects are significant in EDTA, DTPA, and TPP complexes of Gd and in the TPP complex of Dy. The simultaneous measurement of these properties is illustrated and represents a promising method for monitoring sodium concentrations and fluxes including fast transport components.

Lithium therapy for mania and depression

The literature on lithium carbonate was reviewed for clues to the processes involved in mania. Lithium has proved effective therapeutically and prophylactically for mania and depressive disorders. Children and adolescents as well as adults tolerate lithium well. Side effects rarely are serious enough to necessitate having lithium therapy. Some success with schizophrenia and schizoaffective disorders has broadened the scope of lithium's therapeutic efficacy but also blunted the expectation for a direct relationship between lithium and the processes involved in mania. Research points to neurotransmitters as contributing to the etiology and symptom pattern of mania.

Prophylaxis and the lithium ratio in bipolar patients

Thirty-five bipolar outpatients treated with lithium carbonate were followed for up to 5 years with the aim of studying the relation of the lithium ratio (LR) and its predictive value. Only male responders were found to have higher LR than male nonresponders. No difference was found between the mean LR of men and women, as a group. Aging also had no effect on LR. Positive family history of affective disorders was correlated with high LR, irrespective of response.

Erythrocyte lithium efflux in bipolar patients and control subjects: the question of reproducibility

The reproducibility of in vitro erythrocyte lithium efflux and lithium efflux in the presence of selected membrane transport inhibitors (phloretin, ouabain, 4,4'-diisothiocyano-2,2'-disulphonic acid stilbene, and p-chloromercury-benzene sulphonate) was investigated in bipolar patients and age- and sex-matched control subjects. Efflux experiments were repeated three times in each patient-control pair within a period of 14 days. No differences were detected between patients and control subjects in any of the parameters measured. All components of lithium efflux showed wide day-to-day variation in the same subject in both patients and control subjects. Intersubject variability, however, was significantly greater than intrasubject variation. Since intraindividual variation of phloretin-inhibited lithium efflux was found to be considerable, and no real patient-control differences could be detected, the significance of this in vitro parameter in bipolar affective illness seems somewhat questionable and should be carefully reconsidered. The relevance of these findings to the putative cell membrane dysfunction in this disease is discussed.

Lithium, sodium and potassium transport in erythrocytes of manic-depressive patients

Different Li, Na and K transport pathways were assessed in erythrocytes from manic-depressive patients. No alteration in the Li-Na countertransport, Na,K cotransport or passive permeabilities was observed in either unipolar or bipolar manic-depressive patients. In addition, acute or chronic lithium treatment did not alter the maximal velocity of either the Li-Na countertransport or the Na,K cotransport. A two-fold reduction of the ouabain-sensitive Na efflux was observed among manic-depressive patients without alteration in the affinity of the Na pump for internal Na.

Lithium transport in red cells of patients with affective disorders

Variation in red cell Li+ transport as mediated by the Li+-Na+ exchange pathway (Li+-Na+ counterflow) appears to cause wide variation between psychiatric patients in the Li+ ratio (erythrocyte/plasma) in vivo during Li+ treatment. We obtained significant correlations between Li+ ratios determined in vivo and several measures of Li+ transport as mediated by Li+-Na+ exchange. Patients with bipolar illness had significantly lower rates of Li+ transport as mediated by this pathway than did normal subjects.

Blood cells as biological trait markers in affective disorders

Data are reviewed on platelet monoamine oxidase activity, red blood cell/plasma lithium ratio, and tritiated imipramine binding to platelet membranes as trait markers for affective disorders. The results of various studies are not in agreement. Differences in methodological procedure are probably central to such discrepancies. At the present time, no single biological abnormality of blood cells has proved to be a trait marker for affective disorders; thus their use to identify vulnerability to mood disorders or predict favourable response to pharmacological treatment appears to be premature.

Lithium ratio in psychiatric patients: a caveat

We divided bipolar patient samples into two groups: Group I (off lithium 10 days to 2 weeks, n = 14) and group II (off lithium 3 weeks or longer, n = 13). Only group I was significantly different from controls. The mean for group II was significantly different from that for group I but not that for controls. Previous reports may have exaggerated the number of "high ratio" patients due to a treatment artifact. We recommend that patients be tested only after having been withdrawn from lithium treatment for 3 weeks or more. Otherwise spurious differences between patients and controls may result.

Trends in research and treatment of affective disorders

Trends in research on affective disorders were reviewed. Studies which described the contribution of neurotransmitters and neuroendocrines to depression, unipolar and bipolar, and manic states were cited. Women more frequently suffer from affective disorders but women's response to different therapies sometimes is more favorable than men's. Age and married status influence sex differences in the incidence of affective disorders. Symptoms of pain and depression intertwine, and response to analgesia may emerge as an index of response to therapy for depression. Trends in pharmacotherapies for affective disorders were reviewed: lithium, tricyclic antidepressants, and MAOI drugs, as well as trends in the employment of ECT and sleep deprivation to relieve symptoms of affective disorders were reviewed.

The red blood cell/plasma lithium ratio: marker of biological heterogeneity within bipolar affective illness?

The red blood cell/plasma concentration ratio (LR) was studied in 45 female patients with bipolar affective illness who responded to prophylactic lithium treatment. Patients were subdivided according to bipolar I vs. bipolar II diagnosis and presence vs. absence of a family history of affective illness. Mean LRs were significantly higher in bipolar II patients and in those with a positive family history of affective illness, but there was no relationship between diagnosis and family history. Results indicate that LR is genetically controlled and may be a biological marker distinguishing bipolar I and bipolar II patients, and also patients with positive or negative family history of affective illness.

Methodological assessment of assays for red cell sodium concentration and sodium-dependent lithium efflux

Assays for red cell sodium concentration and sodium-dependent lithium efflux were studied from a methodological point of view. The technical errors for sodium concentration--based on concurrent analysis of randomized blind duplicate samples--was 2.5% and for lithium efflux 6.4%. Based on repeated measures in the same individual, the assays were stable over time and reproducible; individual differences at a mean interval of 16 days were not significantly different. A wait of two hours from time of phlebotomy to analysis yielded a slight (3.8%) but significant fall in the sodium concentration; no further change was found at four hours. No change occurred in the lithium efflux over time. A standardized breakfast containing 664 mg sodium did not affect the measurements when fasting and three-hour postprandial levels were compared. The ratios of intra- to inter-individual variance were small--0.04 for red cell sodium concentration and 0.09 for sodium-stimulated lithium efflux. These assays appear to be reproducible and stable and can be applied in large scale field trials.

The activity of the lithium--sodium countertransport system in erythrocytes in depression and mania

The activity of the lithium--sodium countertransport system in erythrocytes was estimated in 16 control subjects and 28 patients suffering from affective disorders (11 bipolar, 17 unipolar) during depression, mania and remission. In all the patients studied, mean estimates of countertransport were significantly lower during an episode than after remission, with low values occurring more frequently in mania than in depression in bipolar patients. The mean values in patients with affective disorders but who were in remission remained lower than those of control subjects. Lowest values occurred more frequently in patients with bipolar than in those with unipolar illness. the possible physiological significance of reductions in the activity of the lithium--sodium countertransport mechanism in red cells was discussed.

Alteration of erythrocyte phosphate transport in primary depressive disorders

Plasma and erythrocyte phosphate levels, concentrations of red cell organic phosphate ester fractions (acid labile and acid resistant phosphate pools) and intracellular ATP content were determined in 16 patients with bipolar depression, in 14 subjects with unipolar depression as a group of primary affective disorders, in 15 patients suffering from neurotic depression and in 45 healthy controls. Simultaneous in vitro measurements were carried out to detect the exchange rates of inorganic phosphate between the extracellular phosphate pool and the different intracellular phosphate fractions, by use of 32P and applying tracer kinetic analysis. Plasma and red cell inorganic phosphate levels, passive phosphate transport and transfer of inorganic phosphate into the membrane ATP pool were significantly lowered in the primary depressive group as compared to the biochemical values observed in the neurotic group and in the healthy controls. The results suggest an alteration in anion transport across the red cell membrane in primary depressive disorders.

Personality correlates of platelet monoamine oxidase activity anbd red cell lithium transport

Platelet monoamine oxidase (MAO) activity and the ratio of red cell to plasma lithium concentrations (Li ratio) may be important in the pathophysiology of, and genetic vulnerability to, some psychiatric disorders. By using the Clinical Analysis Questionnaire, we assessed personality correlates of MAO activity and the Li ratio in vitro in a sample of psychiatrically normal adult women. We found that there were correlates of each variable, and a unique constellation of personality traits when the two variables were considered simultaneously.

The influence of external sodium and potassium on lithium uptake by primary brain cell cultures at "therapeutic" lithium concentration

The ionic regulating of lithium homeostasis and steady-state intra:extracellular lithium distribution in the brain can be approached by experimental methods using intact nerve cells in vitro. Primary cultures prepared from chick embryonic brain were applied to study the effect of extracellular sodium and potassium on the lithium uptake of nerve cells at 'therapeutic' lithium concentration (1.5 mM). Lithium influx and the level of steady-state intracellular lithium were significantly reduced by increasing the external sodium concentration. At physiological extracellular sodium level, the steady-state content of lithium in the brain cells was about half of that observed in the presence of 10 mM sodium in the incubation media and the value of the intra:extracellular lithium distribution ratio was below 1. External potassium (0.5 - 3mM) strongly inhibited lithium uptake of the nerve cells. Ouabain (10(-4)M) had no effect on this potassium-sensitive lithium uptake in Tyrode media. Sodium influx studied by isotope tracer methodology was higher in cultures preloaded with lithium as compared to that of the controls. It can be concluded that sodium and potassium ions, at physiological concentrations, significantly influence lithium uptake as well as the intra:extracellular lithium distribution in brain cell cultures.