Lithium and the kidney

Chronic lithium therapy and urine concentrating ability in individuals with bipolar disorder: association between daily dose and resistance to vasopressin and polyuria

Introduction

Lithium treatment can induce nephrogenic diabetes insipidus (NDI), but no consensus intervention is offered to date. We evaluated in these patients patterns of urine concentration and the correlates of 24-hour urine output.

Methods

Prospective, single-center, observational study of 217 consecutive lithium-treated individuals, with 24-hour urine collection, desmopressin (1-deamino-arginine vasopressin [DDAVP]) concentrating test, fasting plasma vasopressin measurement (copeptin measurement in n = 119), and measured glomerular filtration rate (mGFR). Maximal urine osmolality (MaxUosm) was the highest level during the DDAVP test.

Results

Of the individuals, 21% displayed polyuria (>3 l/d), but 55% displayed elevated fasting vasopressin level (>5 pg/ml). Uosm was significantly lower and urinary output and free water clearance were significantly higher in individuals treated for >10 years. MaxUosm was >600 mOsm/KgH₂O in 128 patients (59%), among which vasopressin was increased in 51%, associated with higher lithium dose (950 [750–1200] vs. 800 [500–1000] mg/d, P < 0.001). All patients with lithium daily dose ≥1400 mg/d had high vasopressin levels. In multivariable analysis, 24-hour urine output was associated with higher lithium daily dose (β 0.49 ± 0.17, P = 0.005), female sex (β −359 ± 123, P = 0.004), daily osmolar intake (β 2.21 ± 0.24, P < 0.001), MaxUosm (β −2.89 ± 0.35, P < 0.001), and plasma vasopressin level (β 10.17 ± 4.76, P = 0.03).

Conclusion

Higher lithium daily dose was associated with higher vasopressin levels and higher urine output, independently of other factors. Daily osmolar intake was also associated with higher 24-hour urine output. These results suggest that controlled salt and protein intake and lithium dose might reduce polyuria in these patients.

Lithium treatment reverses irradiation-induced changes in rodent neural progenitors and rescues cognition

Cranial radiotherapy in children has detrimental effects on cognition, mood, and social competence in young cancer survivors. Treatments harnessing hippocampal neurogenesis are currently of great relevance in this context. Lithium, a well-known mood stabilizer, has both neuroprotective, pro-neurogenic as well as antitumor effects, and in the current study we introduced lithium treatment 4 weeks after irradiation. Female mice received a single 4 Gy whole-brain radiation dose on postnatal day (PND) 21 and were randomized to 0.24% Li2CO₃ chow or normal chow from PND 49 to 77. Hippocampal neurogenesis was assessed on PND 77, 91, and 105. We found that lithium treatment had a pro-proliferative effect on neural progenitors, but neuronal integration occurred only after it was discontinued. Also, the treatment ameliorated deficits in spatial learning and memory retention observed in irradiated mice. Gene expression profiling and DNA methylation analysis identified two novel factors related to the observed effects, Tppp, associated with microtubule stabilization, and GAD2/65, associated with neuronal signaling. Our results show that lithium treatment reverses irradiation-induced loss of hippocampal neurogenesis and cognitive impairment even when introduced long after the injury. We propose that lithium treatment should be intermittent in order to first make neural progenitors proliferate and then, upon discontinuation, allow them to differentiate. Our findings suggest that pharmacological treatment of cognitive so-called late effects in childhood cancer survivors is possible.

Lithium Accumulates in Neurogenic Brain Regions as Revealed by High Resolution Ion Imaging

Lithium (Li) is a potent mood stabilizer and displays neuroprotective and neurogenic properties. Despite extensive investigations, the mechanisms of action have not been fully elucidated, especially in the juvenile, developing brain. Here we characterized lithium distribution in the juvenile mouse brain during 28 days of continuous treatment that result in clinically relevant serum concentrations. By using Time-of-Flight Secondary Ion Mass Spectrometry- (ToF-SIMS) based imaging we were able to delineate temporospatial lithium profile throughout the brain and concurrent distribution of endogenous lipids with high chemical specificity and spatial resolution. We found that Li accumulated in neurogenic regions and investigated the effects on hippocampal neurogenesis. Lithium increased proliferation, as judged by Ki67-immunoreactivity, but did not alter the number of doublecortin-positive neuroblasts at the end of the treatment period. Moreover, ToF-SIMS revealed a steady depletion of sphingomyelin in white matter regions during 28d Li-treatment, particularly in the olfactory bulb. In contrast, cortical levels of cholesterol and choline increased over time in Li-treated mice. This is the first study describing ToF-SIMS imaging for probing the brain-wide accumulation of supplemented Li in situ. The findings demonstrate that this technique is a powerful approach for investigating the distribution and effects of neuroprotective agents in the brain.

Inherited secondary nephrogenic diabetes insipidus: concentrating on humans

The study of human physiology is paramount to understanding disease and developing rational and targeted treatments. Conversely, the study of human disease can teach us a lot about physiology. Investigations into primary inherited nephrogenic diabetes insipidus (NDI) have contributed enormously to our understanding of the mechanisms of urinary concentration and identified the vasopressin receptor AVPR2, as well as the water channel aquaporin-2 (AQP2), as key players in water reabsorption in the collecting duct. Yet, there are also secondary forms of NDI, for instance as a complication of lithium treatment. The focus of this review is secondary NDI associated with inherited human diseases, such as Bartter syndrome or apparent mineralocorticoid excess. Currently, the underlying pathophysiology of this inherited secondary NDI is unclear, but there appears to be true AQP2 deficiency. To better understand the underlying mechanism(s), collaboration between clinical and experimental physiologists is essential to further investigate these observations in appropriate experimental models.

Distress due to lithium-induced polyuria: exploratory study

Lithium-induced polyuria, although common, often goes unrecognized. The purpose of the present study was therefore to investigate the complaints of polyuria, and distress and functional impairment associated with polyuria, in 56 patients with bipolar disorder on long-term lithium treatment. All participants underwent 24-h urine collection, and renal function tests. Polyuria (24-h urine volume > 3 L) was found in 70% of subjects. Unless directly enquired about, polyuria was underreported. Impairment in work and daily routine due to increased urine output/frequency was associated with 24-h urine volumes. Polyuria is a highly prevalent, distressing and impairing side-effect of long-term lithium treatment, requiring due attention.

Elevated Serum Creatinine and a Normal Urinalysis: A Short Differential Diagnosis in the Etiology of Renal Failure

OBJECTIVE

The diagnosis of renal failure with a normal urinalysis represents a short differential diagnosis that has not been characterized in the literature. This study was designed to identify the specific disease states that encompass this interesting renal condition.

MATERIAL

The Regenstrief database, which is an electronic medical record containing inpatient laboratory and other clinical data for patients admitted to Wishard Memorial Hospital, was utilized to provide data for this study.

METHODS

The database was culled to provide data for hospitalized patients admitted between March 1, 1992, and March 1, 2001, with the concurrent findings of a serum creatinine greater than or equal to 2 mg/dL, a normal urinalysis, and diagnoses of obstructive uropathy, multiple myeloma, prerenal azotemia, hypertensive nephrosclerosis, interstitial nephritis, renal vascular disease, hypokalemic nephropathy, and hypercalcemia, as identified by their corresponding ICD-9 codes.

RESULTS

A search of the Regenstrief database yielded a total of 190,343 patient admissions. There were 515 patient admissions with renal failure and a concurrent normal urinalysis. The largest specific diagnostic categories within this group were hypertension and prerenal azotemia.

CONCLUSIONS

An elevated serum creatinine and normal urinalysis present a short differential for the etiologies of renal failure and include such entities as hypertensive nephrosclerosis, prerenal azotemia, obstructive nephropathy, interstitial nephritis, renal vascular disease, and various electrolyte abnormalities. An awareness of these specific disease states may lead to an earlier diagnosis and more effective treatment of renal failure.

Dysregulation of renal aquaporins and epithelial sodium channel in lithium-induced nephrogenic diabetes insipidus

Lithium is used commonly to treat bipolar mood disorders. In addition to its primary therapeutic effects in the central nervous system lithium has a number of side effects in the kidney. The side effects include nephrogenic diabetes insipidus with polyuria, mild sodium wasting, and changes in acid/base balance. These functional changes are associated with marked structural changes in collecting duct cell composition and morphology, likely contributing to the functional changes. Over the past few years, investigations of lithium-induced renal changes have provided novel insight into the molecular mechanisms that are responsible for the disturbances in water, sodium, and acid/base metabolism. This includes dysregulation of renal aquaporins, epithelial sodium channel, and acid/base transporters. This review focuses on these issues with the aim to present this in context with clinically relevant features.

The trace elements in response to lithium intoxication in renal failure

The polyuric syndrome that develops as a consequence of chronic administration of lithium salts is most frequent and often causes complication in the treatment of manic depressive disease with the administration of drugs. It is known that kidneys play an essential role in systematic depositing of toxic metals. The purpose of this study was not only the determination of dose-dependent lithium concentration in serum and urine but also an estimation of sensitive biochemical indicators of nephrotoxicity detectable at an early stage after the administration of lithium carbonate to rats. Animals were given orally lithium salt to female Wistar rats at the dose of 10 and 20mg Li/kg daily during 5 weeks. In the urine diuresis protein concentration, copper, zinc, lithium and N-acetyl-beta-glucoaminidase (NAG) activity were determined. In the serum also lithium, copper and zinc were analyzed. The results of the experiments indicate that the changes in urinary concentrations of essential copper, proteins, NAG activity and diuresis were observed when the concentration of lithium was ca. 9.79+/-1.68 mmol Li/L and in serum it corresponded to 0.3+/-0.06 mmol Li/L. These values corresponded to total doses of 150 mg Li/kg body weight administered to rats. In summary the increase of copper concentration, diuresis and urinary concentrations of protein and the NAG activity may be interpreted as a general metabolic response of kidneys induced by lithium detectable as an earlier indicator of nephrotoxicity. Therefore, regular determinations of lithium concentrations in serum of patients are important tools in the prevention of intoxication.

Upregulation of the expression of vasopressin gene in the paraventricular and supraoptic nuclei of the lithium-induced diabetes insipidus rat

The expression of arginine vasopressin (AVP) gene in the paraventricular (PVN) and supraoptic nuclei (SON) was investigated in rats with lithium (Li)-induced polyuria, using in situ hybridization histochemistry and radioimmunoassay. The male Wistar rats consuming a diet that contained LiCl (60 mmol/kg) for 4 weeks developed marked polyuria. The Li-treated rats produced a large volume of hypotonic urine with low ionic concentrations. Plasma sodium concentrations were found to be slightly increased in the Li-treated rats compared with those in controls. Plasma concentration of AVP and transcripts of AVP gene in the PVN and SON were significantly increased in the Li-treated rats compared with controls. These results suggest that dehydration and/or the activation of visceral afferent inputs may contribute to the elevation of plasma AVP and the upregulation of AVP gene expression in the PVN and the SON of the Li-induced diabetes insipidus rat.

Dissociation between water and lithium transport during acute changes in plasma potassium concentration in dog kidney

Lithium clearance is often used as a marker for proximal tubular water transport. Proximal tubular transport may be modulated by changing plasma potassium concentration. The aim of the present study was to examine the effect of acute changes in plasma potassium concentration on proximal tubular fluid and lithium transport. Clearance studies were performed in seven anaesthetised, volume-expanded dogs treated with amiloride (1 mg kg-1 body weight) to block distal tubular potassium secretion, and with bumetanide (30 micrograms kg-1 body weight) to inhibit sodium reabsorption in Henle's loop. When plasma potassium concentration was raised from 2.6 +/- 0.2 to 7.9 +/- 0.2 mmol l-1, water reabsorption decreased from 23.9 +/- 2.9 to 19.8 +/- 2.2 ml min-1, whereas lithium reabsorption increased from 10.5 +/- 2.3 to 18.1 +/- 2.3 mumol min-1, at constant glomerular filtration rate. We conclude that acute elevation of plasma potassium concentration inhibits proximal tubular fluid reabsorption, but stimulates renal lithium reabsorption. Thus, lithium reabsorption cannot be used as a marker for proximal tubular transport during acute changes in plasma potassium concentration.

Acute effects of physiological increments of brain natriuretic peptide in humans

To investigate the effects of physiological increases in plasma brain natriuretic peptide concentration in humans, we studied six healthy volunteers who received incremental infusions (0.25 pmol/kg per minute in the first hour and 0.50 pmol/kg per minute in the second) of synthetic human brain natriuretic peptide-32 in a placebo-controlled, crossover study. Peptide plasma levels were 1.69 +/- 0.39 pmol/L at baseline and rose 1.5- and 3-fold with the lower and higher doses, respectively. These values were within the normal range and also comparable to those reported in patients with mild essential hypertension. The urinary excretion rate of cGMP also increased during brain natriuretic peptide infusion, indicating stimulation of natriuretic peptide receptors. Peptide administration induced a significant 1.7-fold increase in urinary sodium excretion without affecting renal plasma flow (para-aminohippurate clearance), glomerular filtration rate (creatinine clearance), and urine flow rate. Fractional proximal sodium reabsorption (lithium clearance method) was unchanged, and fractional distal sodium reabsorption significantly decreased. Brain natriuretic peptide caused no changes in arterial pressure, heart rate, hematocrit, and serum proteins, but it exerted an inhibitory effect on the renin-aldosterone axis, as indicated by the significant 50% or more decrease of plasma renin activity and urinary excretion rate of aldosterone. These results suggest that brain natriuretic peptide may be involved in the overall regulation of body fluid and cardiovascular homeostasis in humans, mainly through its natriuretic and endocrine effects.

The effects of prolonged lithium exposure on the immune system of normal control subjects: serial serum soluble interleukin-2 receptor and antithyroid antibody measurements

The purpose of this study was to begin evaluating the effects of lithium carbonate on in vivo immune function in normal controls. We postulated that lithium carbonate would stimulate lymphocytes but would not affect the production of antithyroid antibodies. Twenty-seven normal controls had blood samples drawn for measurements of serum soluble interleukin-2 receptors (SIL-2Rs), antithyroglobulin antibodies, and antimicrosomal antibodies prior to and after approximately 1 and 4 weeks of treatment with lithium carbonate at therapeutic blood levels. Subjects had a small but statistically significant increase in serum SIL-2Rs after 4 weeks of lithium treatment (446.3 +/- 177.2 U/ml versus 497.6 +/- 232.3 U/ml, p = 0.033). There was no increase in the prevalence of antithyroglobulin or antimicrosomal antibodies with lithium treatment nor did lithium act as an adjuvant to increase the titers in subjects with preexisting antithyroid antibodies.

Lithium intoxication: a coordinated treatment approach

This case illustrates the clinical features of lithium intoxication and the problems in treating it that may arise as a result of lithium's effects on the kidney. It also demonstrates the difficulties that can develop when a delicate physiologic balance is inadvertently disrupted by nonpharmacologic interventions such as seclusion and consequent restriction of access to food and water. Patients with lithium-induced urine-concentrating defects are especially at risk for dehydration, and care must be taken to ensure adequate fluid and salt intake. This case also shows how intense negative feelings evoked by chronically mentally ill patients can adversely affect their psychiatric and medical care. While such feelings are inevitable, their impact may be lessened by improved communication and coordination between the medical and psychiatric systems of care and by the presence of psychiatrists in the general medical hospital.

Lithium side effects in the medically ill

OBJECTIVE

This review will include the general pharmacology of lithium and discuss its effects on various organ systems, with emphasis on the medically ill patient as well as the geriatric patient with multiple medical problems.

METHODS

A full literature review on the side effects of lithium was performed. Attention is focused on the medically ill and possible drug interactions.

RESULTS

This review points to the numerous problems which can result in toxicity in the medically ill or the geriatric patient.

CONCLUSION

Serious side effects can be avoided with proper drug monitoring and knowledge of potential drug interactions.

Dental conditions in patients with bipolar disorder on long-term lithium maintenance therapy

Bipolar disorder (manic depressive disease) affects 1% of the United States population. These persons suffer from episodes of extreme elation followed by long periods of depression. Dental screening examinations of 40 patients consecutively admitted to the medical center with this diagnosis were performed. Poor oral hygiene, accumulations of supragingival and subgingival calculus, extensive dental caries, and numerous missing teeth were commonly identified. The majority of patients with bipolar disorder are treated with lithium carbonate. The physiological effects of lithium, and its interaction with drugs used in dentistry are reviewed, and disease-specific modifications in dental treatment are recommended.

Lithium treatment reduces the renal kallikrein excretion rate

Lithium salts are widely used agents for the prophylactic treatment of affective disorders. Lithium salts may be associated with distal nephron dysfunction. Kallikrein is a protease which is generated by the distal nephron. We used an amidolytic assay of chromatographically purified enzyme to determine the urinary excretion rate of active kallikrein in relation to lithium treatment. All plasma lithium concentrations were within the therapeutic range (0.4 to 0.9 mmol/liter). In 15 patients the urinary excretion rate of active kallikrein was 267.4 +/- 65.6 mU/24 hrs before lithium treatment, and fell to 117.8 +/- 39.6 mU/24 hrs (P less than 0.05) on day 14 of lithium treatment. This reduction was associated with a decrease of immunoreactive kallikrein in the same urines by 66%. In another 15 patients who had undergone lithium therapy for an average period of 5.6 years, the urinary excretion rate of active kallikrein was 86.1 +/- 14.5 mU/24 hrs, while 21 age-matched healthy controls had an excretion rate of 364.1 +/- 58.4 mU/24 hrs (P less than 0.05). Measurements of immunoreactive kallikrein in the same urine samples demonstrated a reduction of kallikrein after long-term lithium treatment by 78%. These observations could not be attributed to changes in creatinine clearance, renal sodium or potassium excretion rates or plasma concentrations of aldosterone and vasopressin. Addition of lithium to the urine in vitro had no demonstrable effect on kallikrein measurement by amidolytic assay. We conclude that lithium in therapeutic plasma concentrations may directly suppress the secretion of kallikrein by renal connecting tubule cells.

Effects of lithium on cAMP generation in cultured rat inner medullary collecting tubule cells

The effects of lithium (Li) on the cAMP system in rat inner medullary collecting tubule cells were studied. While acute exposure to 5 mM Li was without effect, 10 mM, 25 mM and 50 mM Li significantly decreased AVP-stimulated cAMP formation. In contrast, cells grown in 5 mM Li for 72 hours which caused no morphologic changes enhanced cAMP formation (fmol/microgram protein) in response to both 10 nM AVP (114.5 +/- 9.2 vs. 71.6 +/- 7.4, P less than 0.005) and 100 nM AVP (182 +/- 14 vs. 120 +/- 8.3, P less than 0.001), N = 16. A similar enhancement was observed when cAMP formation was stimulated by a post-receptor agonist, cholera toxin. The role of eicosanoids was examined with 5 microM meclofenamate which reversed Li-enhanced cAMP formation in response to both AVP and cholera toxin. To define the eicosanoid responsible, cyclooxygenase products were measured. Prostaglandin E2 and thromboxane B2 synthesis were unchanged by Li, but the production of prostacyclin was significantly (P less than 0.02) increased. Prostacyclin (3 microM) mimicked the effect of Li to enhance the response to 10 nM AVP as cAMP levels increased from 100 +/- 11 to 173 +/- 13, P less than 0.05. The experiments suggest that acute exposure of Li at concentrations of 10 mM or greater inhibit cAMP formation but prolonged Li exposure enhances cAMP formation by increasing the formation of prostacyclin.

Health impact of renal disease due to nephrotoxicity

Both acute and chronic renal failure are reported in the context of nephrotoxicity. This overview of some major nephrotoxins reflects both the magnitude and the cost of this preventable health problem. Aminoglycosides and other antibiotics, contrast media and nonsteroidal anti-inflammatory drugs are the best documented nephrotoxins related to acute renal failure. Analgesic nephropathy is the best known drug-induced chronic renal disease. The cost of renal failure due to nephrotoxicity is not easy to compute. Drug-induced acute renal failure costs more than 2750 ECU per patient, depending on whether dialysis is required or not, and chronic renal failure costs at least 128,000,000 ECU annually in the European Communities. Recent epidemiological evidence, however, indicates that the cost may be even higher.

The nephrotoxic potential of drugs and chemicals. Pharmacological basis and clinical relevance

Scores of drugs in common clinical use are capable of inflicting various degrees of damage to the kidney. Similarly, a large number of widely employed chemicals may adversely affect renal tissue as part of their toxic potential. A xenobiotic may damage the kidney by more than one mechanism. For example, NSAIDs may cause decreased renal perfusion, interstitial nephritis, primary glomerulopathy and/or altered potassium homeostasis. A large number of drugs and chemicals inflict their damage on the renal tubular cell secondary to intracellular accumulation to concentrations substantially higher than in the plasma or in other tissues. These include aminoglycosides, mercury and carbon tetrachloride and cephaloridine. Drug-induced interstitial nephritis is characterised by inflammatory lesions of the renal interstitium developed after at least 7 to 10 days of therapy. The immunological nature of this reaction is suggested by the associated fever, maculopapular rash and arthralgia observed in some of the patients. Although eosinophilia, eosinophiluria, and raised blood IgE levels are characteristic, immunoglobulins are not deposited in renal tissue, and the basic mechanism has not been elucidated. Renal biopsy demonstrates oedema and interstitial inflammatory reaction, mainly with lymphocytes, monocytes, eosinophils and plasma cells. Less frequent, vasculitis of small vessels or granulomatous reaction may develop, leading to necrotising glomerulonephritis. The drugs most commonly causing acute interstitial nephritis are methicillin, ampicillin, cephalosporins, rifampicin (rifampin), sulphonamides, phenindione and allopurinol. Other penicillins, NSAIDs, phenytoin, thiazides and frusemide (furosemide) are less frequently associated with this syndrome. Drugs and chemicals may affect renal function by pharmacologically decreasing glomerular filtration rate and/or renal blood flow. These include the NSAIDs, radiological contrast media and cyclosporin. Normal renal function depends upon an intact glomerular apparatus. Many drugs and chemicals are capable of damaging the glomerulus, causing its increased permeability to large molecules such as proteins. Several drugs including d-penicillamine, thiopronine, captopril, pyrithioxine and methimazole, are believed to exert their damage through their sulfhydryl group which bind with high affinity to glomerular structures. A variety of xenobiotics or their metabolites may be deposited in the renal tubule causing obstruction of urine flow and a secondary damage to tubular epithelium. Sulphonamides, methotrexate and ethylene glycol are good examples.(ABSTRACT TRUNCATED AT 400 WORDS)

Lithium-induced structural changes in the cortical distal nephron localized by computer-assisted three-dimensional reconstruction

Lithium treatment is known to cause tubule dilation in distal nephron segments both in rat and in man. However, due to the heterogeneous cell composition of the distal nephron and the cellular changes following lithium treatment, it has been difficult to identify the structurally changed segments. In this study we have therefore applied computer-assisted reconstruction of cortical distal nephron segments. Tubule dilation was demonstrated in connecting and initial collecting tubules and in the first part of cortical collecting ducts (CCD) whereas it was absent from distal straight and distal convoluted tubules. Principal cells (P cells) in the CCD showed swelling of the cytoplasm, accumulation of actin-like microfilaments, and abnormal arrangements of basolateral membranes. Connecting tubule cells (CNT cells) showed similar but less pronounced changes. Intercalated cells (I cells) showed an accumulation of vesicles in the apical cytoplasm and a reduced luminal surface area. Lesions in P and CNT cells may, at least in part, explain the diabetes insipidus and sodium loss found during lithium treatment. Proton secretion in I cells is probably mediated by an ATPase present in the luminal membrane. The reduction in area of this membrane may explain why lithium-treated animals have a lowered ability to excrete an acid load.

Lithium intoxication with acute renal failure and death

A 65-year-old female presented with only gastrointestinal symptoms eight to ten hours after an acute ingestion of an unknown amount of lithium carbonate. The serum lithium concentration was 8.5 mEq/L. Forty-eight hours postingestion she developed acute renal failure, deteriorating mental status, and cardiovascular collapse. Despite both hemodialysis and peritoneal dialysis the patient died approximately four and one-half days after ingestion. A direct nephrotoxic effect of lithium is proposed.

The effect of lithium on the renal response to the dopamine prodrug gludopa in normal man

1. The effect of oral lithium on the renal response to gamma-L-glutamyl-L-dopa (gludopa, 25 micrograms kg-1 min-1) was investigated in seven normal males. 2. Gludopa at this dose produced an 800-fold increase in urine dopamine excretion. It was natriuretic and suppressed plasma renin activity without altering blood pressure and pulse. 3. Lithium alone increased sodium excretion and stimulated plasma renin activity. However, it abolished the natriuresis produced by gludopa. 4. Gludopa did not significantly affect lithium clearance. 5. This study suggests that lithium interacts with dopamine at the proximal tubule and that the lithium clearance method is not suitable for investigating dopaminergic mechanisms in the kidney.

A morphometric and ultrastructural study of lithium-induced changes in the medullary collecting ducts of the rat kidney

Rats were given a lithium-containing diet (40 mmol/kg) to study the effect of lithium on the structure of collecting ducts from the inner stripe of the outer medulla. The results show that there is a significant increase in the volume density of collecting ducts already after one week on this diet. The volume density of both intercalated and principal cells increases, whereas the volume density of mitochondria in the cytoplasm increases in the intercalated cells only. The increased volume of both principal and intercalated cells seems to be part of a general hyperplasia and hyperactivity of the collecting duct, which may in some way be related to the effects of lithium on vasopressin-mediated mediated water transport. The specific changes in the intercalated cells may be a consequence of the effects of lithium on distal nephron potassium and hydrogen ion transport in the distal nephron.

Longitudinal evaluation of glomerular filtration rate during long-term lithium therapy

Lithium produces many renal effects, but the important question of whether or not it causes chronic interstitial nephritis with consequent reduced glomerular filtration rate (GFR) remains unanswered. The several studies carried out in this area have been cross-sectional and, therefore, have not contained prospective information regarding creatinine clearance. The present study provides data from seven patients in whom creatinine clearances were obtained bracketing an average span of 7.5 years of continuous lithium therapy. Over this time, there was no significant change either in mean serum creatinine concentration or in average creatinine clearance (first determination: 1.1 +/- 0.1 [SE] mg/dL, 99 +/- 8 mL/min/1.73 m2; second determination 1.0 +/- 0.1, 105 +/- 4, respectively). The data, thus, support preservation of GFR during long-term lithium therapy.

Lithium orotate in the treatment of alcoholism and related conditions

The subjects were 42 alcoholic patients (33 males and 9 females) who were treated with lithium orotate during an alcohol rehabilitation program in a private clinical setting for at least six months. They derive from a total number of 105 patients who received this treatment initially, while the remainder discontinued the treatment within six months. The data were collected from a private practice record and the follow-up varied between six months and 10 years. The 42 patients studied displayed a multitude of complaints in addition to chronic alcoholism. These included liver dysfunction, seizure disorders, headaches, hyperthyroidism, affective disorders. Meniere's syndrome, liver and lung cancers. Thirty-six of the 42 patients studied had been hospitalized at least once for the management of their alcoholism. Lithium orotate was given, 150 mg daily, with a diet low in simple carbohydrates and containing moderate amounts of protein and fat. In addition, calcium orotate (for hepatic involvement), magnesium orotate, bromelaine, and essential phospholipids (for cardiac problems), and supportive measures were instituted, if required. Lithium orotate proved useful as the main pharmacologic agent for the treatment of alcoholism. Ten of the patients had no relapse for over three and up to 10 years, 13 patients remained without relapse for 1 to 3 years, and the remaining 12 had relapses between 6 to 12 months. Lithium orotate therapy was safe and the adverse side effects noted were minor, i.e., eight patients developed muscle weakness, loss of appetite or mild apathy. For these patients, the symptoms subsided when the daily dose was given 4 to 5 times weekly.(ABSTRACT TRUNCATED AT 250 WORDS)

Myocardial changes in rats with lithium-induced uraemia

The possible effects of lithium on myocardial morphology were studied at the light-microscopic level in three different rat models: (i) rats with chronic renal failure due to lithium administration for 8-16 weeks after birth, (ii) normal, adult rats treated with lithium for 16 weeks, and (iii) new-born rats exposed to lithium in their prenatal life. Morphological changes were found in 57% of the male rats with lithium-induced uraemia after lithium administration for 16 weeks postnatally. The changes comprised myocytic degeneration and necrosis associated with infiltration of lymphocytes, histiocytes and plasma cells. This morphological picture is different from the myocardial changes associated with chronic renal failure. Male rats with chronic uraemia after withdrawal of lithium 8 weeks postnatally showed no myocardial changes after 16 weeks. Also, male rats with normal renal function had no myocardial changes after 16 weeks on lithium, but these rats had a significantly lower plasma level of lithium than the lithium-uraemic rats (0.8 vs. 1.4 mmol/l). It is suggested that myocarditis was a consequence of persistent high plasma levels of lithium maintained in the lithium-uraemic rats and that cardiotoxic effects of lithium may be potentiated by concomitant renal failure.

Pathogenesis of nephrogenic diabetes insipidus due to chronic administration of lithium in rats

A polyuric syndrome with nephrogenic diabetes insipidus (NDI) is a frequent consequence of prolonged administration of lithium (Li) salts. Studies in the past, mainly the acute and in vitro experiments, indicated that Li ions can inhibit hydroosmotic effect of [8-arginine]vasopressin (AVP) at the step of cAMP generation in vitro. However, the pathogenesis of the NDI due to chronic oral administration of low therapeutic doses of Li salts is not yet clarified. We conducted a comprehensive study to clarify the mechanism by which Li administered orally for several weeks induces polyuria and NDI in rats. Albino rats consuming a diet which contained Li (60 mmol/kg) for 4 wk developed marked polyuria and polydipsia; at the end of 4 wk the plasma Li was 0.7 +/- 0.09 mM (mean +/- SEM; n = 36). Li-treated rats had a significantly decreased (-33%) tissue osmolality in papilla and greatly reduced cortico-papillary gradient of urea (cortex--43%; medulla--64%; papilla--74%). Plasma urea was significantly (P less than 0.001) lower in Li-treated rats (5.4 +/- 0.2 mM) compared with controls (6.8 +/- 0.3 mM). Medullary collecting tubules (MCT) and papillary collecting ducts (PCD) microdissected from Li-treated animals had higher content of protein than MCT and PCD from the control rats. The cAMP accumulation in response to AVP added in vitro was significantly (delta = -60%) reduced. Also, the cAMP accumulation in MCT and PCD after incubation with forskolin was markedly lower in Li-treated rats. Addition of 0.5 mM 1-methyl,3-isobutyl-xanthine did not restore the cAMP accumulation in response to AVP and forskolin in MCT from Li-treated animals. In collecting tubule segments from polyuric rats with hypothalamic diabetes insipidus (Brattleboro homozygotes) the AVP-dependent cAMP accumulation was not diminished. The activity of adenylate cyclase (AdC) in MCT of Li-treated rats, both the basal and the activity stimulated by AVP, forskolin, or fluoride, was significantly (delta approximately equal to -30%) reduced, while the activity of cAMP phosphodiesterase (cAMP-PDIE) in the same segment showed no significant difference from the controls. Also, the content of ATP in MCT microdissected from Li-treated rats and incubated in vitro did not differ from controls. The rate of [14C]succinate oxidation to 14CO2 in MAL was inhibited (-77%) by 1 mM furosemide, which indicates that this metabolic process is coupled with NaCl cotransport in MAL. The rate of (14)CO(2) production from [14C]succinate in MAL was not significantly different between control and Li-treated rats. In MCT of control rats, the rate of [14C]succinate oxidation was approximately 3 times lower than in MAL. The rate of (14)CO(2) production from [(14)C]succinate in MCT of Li-treated rats was significantly (delta +33%) higher than in MCT dissected from control rats. Based on these results, we conclude that at least two factors play an important role in the pathogenesis of NDI consequent to chronic oral administration of Li: (a) decreased ability of MCT and PCD to generate and accumulate cAMP in response to stimulation by AVP; this defect is primarily due to diminished activity of AdC in these tubular segments caused by prolonged exposure to Li; and (b) lower osmolality of renal papillary tissue, due to primarily to depletion of urea, which decreases osmotic driving force for water reabsorption in collecting tubules. On the other hand, NaCI reabsorption in MAL is apparently not affected by chronic Li treatment.

Lithium induced interstitial nephropathy associated with chronic renal failure. Reversibility and correlation between functional and structural changes

We have previously shown that administration of lithium to rats in the first weeks after birth results in a severe interstitial nephropathy. The aim of the present work was to study the relationship between functional impairment and structural lesions and to evaluate whether the nephropathy regresses after withdrawal of lithium. Three groups of animals were studied: 16 weeks-old controls (group A), rats treated with lithium for 16 weeks (group B) and rats treated for 8 weeks followed by 8 weeks without lithium (group C). Plasma urea and renal concentrating ability were determined and one kidney fixed by vascular perfusion with glutaraldehyde for light microscope morphometry. The results show a significant reduction in renal function after lithium treatment. There was a highly significant reduction in proximal tubular length and a pronounced increase in interstitial volume due to severe fibrosis. The total mass of glomerular tufts was also reduced, but not when this parameter was divided by the body weight. Sclerotic glomeruli were not observed. The structural and functional lithium-induced lesions are independent of sex and irreversible, since they persist 8 weeks after withdrawal of lithium. It is proposed that lithium-induced interstitial fibrosis is followed by proximal tubular atrophy with a reduction in the amount of functioning proximal tubules. This leads to a decrease in proximal tubular reabsorption of sodium and a disturbance in the glomerulo-tubular balance resulting in a decrease in glomerular filtration rate.

Lithium-induced uremia in rats - a new model of chronic renal failure

Three groups of new-born rats were studied: Group Li/Li treated with Li for 16 weeks, group Li/C treated for 8 weeks followed by 8 weeks without Li, and Group C/C 16 weeks old controls. Both Li-treated groups showed severe reduction of renal function, particularly group Li/Li, where the mean GFR was reduced by 80%. Plasma urea, creatinine, and osmolality were increased, blood hemoglobin and hematocrit were reduced, whereas plasma Na, K, and standard bicarbonate were unchanged. Na clearance was maintained and fractional Na excretion thus increased. Fractional Li excretion was also increased, indicating inhibition of proximal tubular salt and water reabsorption. Renal concentrating ability was markedly reduced. When Li was withdrawn, plasma urea levels remained unchanged or continued to rise, and the concentrating defect persisted. The results demonstrate that Li administration to new-born rats causes irreversible chronic renal failure which may progress even in the absence of Li. This model of chronic renal failure has several characteristics in common with chronic renal failure in humans.

Effects of lithium on water intake and renal concentrating ability in rats with vasopressin-deficient diabetes insipidus (Brattleboro strain)

Male and female Long Evan rats and Brattleboro rats with ADH-deficient diabetes insipidus were treated with lithium administered in the diet for 12 weeks. The plasma lithium level was about 1 mmol/l in all groups. Lithium caused polydipsia and polyuria and lowering of renal concentrating ability in normal rats. In rats with ADH deficiency lithium tended to increase water intake, but did not influence spontaneous urine osmolality or maximal urine osmolality during water deprivation. The results indicate that the renal concentrating defect caused by lithium in rats can be explained by ADH-blockade as the only mechanism. However, there is circumstantial evidence that lithium in addition may stimulate thirst mechanisms by an ADH-independent action.

Severe functional and structural changes caused by lithium in the developing rat kidney

Lithium (Li) was administered to rats during maternal pregnancy and/or 8 weeks post-natally, to study the effects on renal function and structure in the developing kidney. Plasma Li was 0.5-1.0 mmol/l 3 and 8 weeks post-natally. Functionally, post-natal Li leads to growth retardation, polyuria with lowering of renal concentration ability, and uremia associated with as much as 80% lowering of the normal glomerular filtration rate (GFR). Pre-natal Li alone did not affect the concentrating ability but caused a 20% increase in GFR when evaluated 8 weeks post-natally. Post-natal Li caused very severe structural changes, consisting of up to 3 mm cortical cysts (= dilated distal convoluted tubules), extensive interstitial fibrosis with cell infiltration, and atrophy of the cortical collecting ducts. Morphometric measurements showed a significant reduction in the volume of the proximal tubular cells. Pre-natal Li caused only slight structural changes, and animals treated both pre- and post-natally were less affected than animals treated post-natally only. The structural changes caused by post-natal Li were unrelated to changes in the concentrating ability but showed a significant correlation with the lowering of the GFR. It is concluded that the post-natally developing rat kidney is particularly sensitive to the nephrotoxic effects of Li, which in low concentrations causes impairment of renal function, leading to uremia. Pre-natal Li exposure by maternal lithium treatment had little effect on renal function and structure when evaluated post-natally.

Distal nephron function in patients receiving chronic lithium therapy

Renal tubular function was studied in 14 patients chronically treated with lithium for affective disorders. Patients were separated into two groups according to the duration of lithium therapy: long-term (35 +/- 7.0 months) and short-term (4.8 +/- 0.8 months). At comparable urine lithium concentrations, patients on long-term therapy had a lower maximal urine osmolality (Umax) and free water reabsorption (TcH2O) than did patients on short-term therapy. The latter group achieved a Umax above 800 mOsm kg H2O. In contrast, both groups of patients failed to increase the urine-blood (U-B) Pco2 gradient normally during acute sodium bicarbonate loading. This low U-B Pco2 was observed at comparable urine bicarbonate concentrations between both groups of patients and controls, and thus was associated with a higher urine pH in patients. These findings indicate that the inability of these patients to achieve a normal U-B Pco2 in a maximally alkaline urine was the result of decreased distal hydrogen ion secretion rather than inability to raise urine bicarbonate concentrations as a result of a concentrating defect. Bicarbonate reabsorptive capacity was normal in our lithium-treated subjects. Both groups of patients achieved a normal U-B Pco2 gradient in response to sodium phosphate loading. They also were able to achieve a minimal urine pH and a maximal acid excretion similar to those of controls in response to a 3-day ammonium chloride loading test. Our data demonstrate that chronic lithium therapy is associated with a mild distal acidification defect disclosed only by the finding of a low U-B Pco2 gradient during sodium bicarbonate loading. This peculiar defect can be found in short-term lithium-treated patients in whom the concentrating capacity is relatively well preserved.