Aromatic l-aminoacid decarboxylase deficiency: unusual neonatal presentation and additional findings in organic acid analysis

Aromatic l-aminoacid decarboxylase (AADC) deficiency is a neurotransmitter defect leading to a combined deficiency of catecholamines and serotonin. Patients are usually detected in infancy due to developmental delay, hypotonia, and extrapyramidal movements. Diagnosis is based on an abnormal neurotransmitter metabolite profile in CSF and reduced AADC activity in plasma. An elevation of vanillactic acid (VLA) has been described as the only abnormality detected in organic acid analysis (OA) of urine. We report a patient who presented in the neonatal period with lethargy, hypotonia, metabolic acidosis, and hypoglycemia. Blood ammonia, lactic acid, and acylcarnitines were normal, but OA of a urine sample showed a small increase of VLA, raising the suspicion of AADC deficiency. The patient was lost to follow-up until the age of 8 months, when he presented with dystonia, abnormal movements, oculogyric crises, and hypothermia. Repeat OA showed not only increased levels of VLA, but also increased vanilpyruvic acid (VPA), N-acetyl-vanilalanine (AVA) and N-acetyl-tyrosine (NAT). Neurotransmitter analysis in CSF showed increased vanilalanine (1200 nmol/L, ref<100) with decreased levels of 5-hydroxy-indoleacetic acid (5-HIAA, < 5 nmol/L; ref 152-462), homovanillic acid (HVA, 83 nmol/L; ref 302-845), and methoxy-hydroxy-phenyl-glycol (<5 nmol/L; ref 51-112). AADC activity in plasma was nearly undetectable. In the urine, low excretion of vanilmandelic acid (<0.3 micromol/mmol creat; ref 0.3-20) and 5-HIAA (0.9 micromol/mmol creat; ref 4-18), was found, but HVA was normal and dopamine even elevated. This contradictory phenomenon of hyperdopaminuria has been described earlier in AADC deficient patients. We postulate that VPA and AVA could originate from vanilalanine (through a transaminase and an acetylase respectively), while NAT could originate from tyrosine through an AA acetylase. This report expands the clinical presentation of AADC deficiency and adds new markers of the disease for OA analysis, improving detection of AADC deficient patients in general metabolic screening procedures.     

In-use stability of monoamine metabolites in human cerebrospinal fluid.

Cerebrospinal fluid (CSF) concentrations of the monoamine metabolites homovanillic acid (HVA) and 5-hydroxyindolacetic acid (5-HIAA) are commonly used to provide information about central nervous system (CNS) dopaminergic and serotonergic activity. However, little attention has been given to the effects of sample handling on the concentrations of these compounds in human CSF. Using high-performance liquid chromatography (HPLC) with electrochemical detection, we observed that, in CSF stored at -80 degrees C, concentrations of the serotonin metabolite 5-HIAA and the dopamine metabolite HVA remained unchanged through six 1-h and six 24-h freeze-thaw cycles. Exposure to bright room light (3 h, 1,230 lux) resulted in a 5-HIAA concentration that was 96.3 +/- 2.0% of the initial and an HVA concentration that was 98.8 +/- 1.03% of initial. The pH of the CSF significantly increased during both freeze-thaw series and while maintained on ice (4 degrees C). These results demonstrate the in-use stability of 5-HIAA and HVA in human CSF under commonly-encountered laboratory conditions.     

Hallucinations in patients with major depression. Interactions between CSF monoaminergic and endorphinergic indices

CSF levels of radioreceptorassayed endorphins Fraction I (EndFI, n = 92) and homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) (n = 118) were measured in patients with major depressive disorders according to Research Diagnostic Criteria (18% were psychotic; 11% hallucinated during the peak of the depressive episode). CSF measures (both "raw" variables and ranks) were uni- and multivariately correlated with both dichotomized and scored measures of hallucinations of any type. Hallucinations were statistically strongly associated with higher HVA levels, irrespective of prior medication with neuroleptics, and with the interactive product HVA X EndFI and the interactive ratio HVA/5-HIAA. Results suggest interactions between dopaminergic, serotonergic and endorphinergic neurotransmission being involved in the biochemical substrate of depressive hallucinatory episodes.     

Effect of long-term storage on monoamine metabolite levels in human cerebrospinal fluid

Concentrations of homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) were measured in human cerebrospinal fluid (CSF) following long-term storage at -20 degrees C for intervals of three to 60 months. No significant changes in HVA levels were detected in CSF stored for up to 60 months. On the other hand, 5-HIAA concentrations remained stable for up to 6 months, but decreased significantly in the specimens stored for longer time intervals. The results indicate that 5-HIAA should be determined within 6 months after CSF collection, while HVA determinations may be delayed.     

Tryptophan, 5-HTP, 5-HT and 5-HIAA in the cerebrospinal fluid and sexual behavior in male rats

No changes were found in the concentration of tryptophan (Trp), 5-hydroxytryptophan (5-HTP), 5-hydroxytryptamine (5-HT) or 5-hydroxyindole acetic acid (5-HIAA) in the cerebrospinal fluid (CSF) of male rats either before sexual activity, immediately after ejaculation of after the postejaculatory refractory period (PEI). Injection of the Trp hydroxylase inhibitor p-chlorophenylalanine (PCPA, 25 or 100 mg/kg i.p. for 3 days) in combination with an injection of the monoamine oxidase inhibitor pargyline (100 mg/kg i.p.) increased the concentration of Trp while decreasing the concentration of 5-HTP, 5-HT and 5-HIAA in the CSF. Furthermore 100 (but not 25) mg/kg PCPA in combination with pargyline caused a significant reduction in the latency to ejaculation. Injection of probenecid (200 mg/kg i.p.), an inhibitor of the transport of 5-HIAA from the CSF, increased the concentration of 5-HIAA in the CSF and slightly prolonged the latency to ejaculation. Sexual activity caused no further increase in CSF 5-HIAA levels in the probenecid-treated rats. Since drug-induced changes in sexual behavior are associated with marked alterations in 5-HT metabolism in the CSF, whereas the changes in the behavior which occur normally are not, these results question the physiological significance of the proposed inhibitory role of 5-HT in male rat sexual behavior.     

MMPI measures of impulsivity and depression correlate with CSF 5-HIAA and HVA in depression but not schizophrenia

Recent studies have linked impulsivity with CSF concentrations of both 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA). One work found a negative correlation between the MMPI psychopathic deviate (Pd) scale and 5-HIAA in personality disordered men (Brown et al., 1982). We found that the 5-HIAA/Pd correlation extends (P less than 0.05) to unmedicated depressed patients (n = 21). A trend was found between HVA and Pd in depression. There was no relationship between either metabolite and the Pd scale in unmedicated schizophrenics (n = 24). A significant inverse correlation was found between the MMPI depression scale and CSF HVA but not 5-HIAA in the depressed patients.     

Significance of decreased lumbar CSF levels of HVA and 5-HIAA in Alzheimer's disease.

The monoamine metabolites homovanillic acid (HVA), 5-hydroxy-indoleacetic acid (5-HIAA) and 4-hydroxy-3-methoxy-phenylglycol (HMPG) were determined in lumbar cerebrospinal fluid (CSF) of 123 patients with Alzheimer's disease (AD) and 57 healthy controls. Despite CSF sampling under strictly standardized conditions, a wide variability in values among both patients and controls was found, as well as fluctuations in repeated samples from individual patients. This suggests that several unknown factors influence the lumbar CSF levels of monoamine metabolites. The AD group showed significantly lower mean levels of HVA (p less than 0.0001) and 5-HIAA (p less than 0.0001) than the control group. A relation between severity of disease and HVA was also found. The widespread neurotransmitter disturbance in AD, together with the nonspecificity of reduced lumbar HVA and 5-HIAA levels, suggests that the changes are nonspecific, secondary to the cerebral degeneration in AD.     

Pre-treatment neurotransmitter metabolites and response to imipramine or amitriptyline treatment

Preliminary data are presented from the NIMH Collaborative Study on the psychobiology of depression, biological studies, dealing with relationships between the pre-treatment levels of the neurotransmitter metabolites 3-methoxy-4-hydrophenethyleneglycol (MHPG), 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) and the subsequent therapeutic response of depressed patients to imipramine or amitriptyline. Eighty-seven depressed patients were studied during pre-treatment and treatment periods. It has been found that (1) both low pre-treatment urinary MHPG and low CSF 5-HIAA values are associated with a response to imipramine; these relationships were not artefacts due to sex or age; (2) there were no significant relationships between pre-treatment urinary MHPG, CSF MHPG, 5-HIAA, or HVA values and the subsequent response, or failure of response, to amitriptyline; (3) there was not a bimodal distribution for CSF 5-HIAA. For both males and females, there were positive and statistically significant correlations between CSF MHPG and urinary MHPG; for the females, there were positive and significant correlations between both urinary and CSF MHPG and CSF 5-HIAA. The theoretical and practical implications of these findings are discussed.     

Cerebrospinal fluid amine metabolites, tryptophan and clinical parameters in depression. Part 2. Psychopathological symptoms

The group of 33 severely depressed female patients was divided into 3 equally large subgroups, separately according to their CSF 5-HIAA, HVA, tryptophan and total plasma tryptophan, and the severity of 17 operationally defined psychopathological symptoms was compared between the subgroups containing the highest and lowest biochemical values. Nonparametric statistical testing yielded significant results on several symptoms, when the subgroups were formed from CSF 5-HIAA and HVA. There was only one significant symptom difference between subgroups separated by CSF tryptophan and a few other differences by plasma tryptophan level. The results indicate that lumbar CSF metabolites correlate more with certain individual symptoms than with the global severity of depression.     

δ-aminolevulinic acid dehydrase (porphobilinogen synthase) in two families with inherited enzyme deficiency

The inheritance of a deficient delta-aminolevulinic acid dehydrase (ALA-D; synonym: porphobilinogen synthase; EC 4.2.1.24) was studied in blood samples of two families over three generations. The propositus in each family was a young male acute hepatic porphyria patient with an almost complete ALA-D deficiency in the homozygous state (ALA-D activity less than 2% of controls). Heterozygotes are clinically non-affected (mean ALA-D 36% of controls). The mode of transmission could be traced by enzyme activity and electrophoretic polymorphism studies. Heterozygotes are detected by the demonstration of enzyme activity in the gel. The notation D was used for the gene expressing the defective enzyme. The "phenotype" D-1 was observed in six, the "phenotype" D-2 in three of all heterozygotes studied. These results are compatible with a single normal allele in heterozygotes responsible for enzyme activity. Quantitative assays and the segregation pattern in both families suggest a 3-allele-system for the inheritance of ALA-D deficiency.     

Effect of pyridoxine deficiency on aromatic L-amino acid decarboxylase in adult rat brain

Summary We have investigated the effect of pyridoxine deficiency on aromatic L-amino acid decarboxylase (AADC) using both dihydroxyphenylalanine (DOPA) and 5-hydroxytryptophan (5HTP) as substrates in the rat brain. The activity ratios of DOPA decarboxylase/5HTP decarboxylase measured under optimal substrate and cofactor concentrations were different in the cerebellum, cerebral cortex, corpus striatum and hypothalamus of the normal rat. In pyridoxine deficiency, there were no parallel decreases in DOPA and 5HTP decarboxylase activities in various brain regions. Dialysis of brain homogenates, in the presence and absence of hydroxylamine, resulted in a total or near total loss of 5HTP decarboxylase activity compared to DOPA decarboxylase activity, indicating that pyridoxal phosphate may be more tightly bound to DOPA decarboxylase than to 5HTP decarboxylase. These results, indicating that pyridoxine deficiency has differential effects on the activity of AADC, are consistent with our earlier observation of non-parallel changes in dopamine and serotonin content in various brain regions of the pyridoxine-deficient rat.     

Amine metabolites and neuroendocrine responses related to depression and suicide

5-Hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) were measured in the lumbar cerebrospinal fluid of 57 drug-free female patients with DSM-III diagnoses of major unipolar or bipolar depression (n = 14), schizophrenic disorder (n = 18), alcohol dependence (n = 13) and a group of other disorders (n = 12). Following lumbar punctures all patients received a dexamethasone suppression test. Fourteen patients had attempted suicide immediately before admission, 4 of them by violent methods. Severity of depression, independent of the diagnosis, was assessed in every patient on the 24-item Hamilton scale. No significant differences in means and variances of amine metabolite or postdexamethasone plasma cortisol concentrations were found among the diagnostic subgroups. Suicidal patients, and in particular those who used violent methods, tended to have lower 5-HIAA, but not HVA, in their CSF; they also more often had non-suppression of cortisol after dexamethasone. Since correlation matrices in the diagnostic subgroups were homogeneous, we calculated partial correlations for the total group: here suicide attempts but not depression, seemed to be significantly correlated with CSF 5-HIAA. Thyrotropin stimulation tests were administered to 6 patients: maximal TSH responses showed a borderline significant correlation with CSF 5-HIAA, and a significant correlation with severity of depression. Neither suicide nor postdexamethasone cortisol levels showed any relation to maximal TSH changes.     

CSF monoamine metabolites in chronic schizophrenic patients who attempt suicide

The monoamine metabolites 5-hydroxindoleacetic acid (5-HIAA), homovanillic acid (HVA) and 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) were measured in the lumbar cerebrospinal fluid (CSF) of 27 chronic schizophrenic patients who at some time had attempted suicide, and were compared with values from 27 chronic schizophrenic patients without a history of attempted suicide. There were no significant differences between either the violent or non-violent attempters and those without a history of attempted suicide in the mean lumbar CSF concentrations of the serotonin metabolite 5-HIAA, the dopamine metabolite HVA, or the norepinephrine metabolite MHPG. Significantly more of the suicide attempters had a previous major depressive episode, had received a course of ECT, and had significantly more psychiatric admissions than those who had never attempted suicide.     

Early maternal rejection affects the development of monoaminergic systems and adult abusive parenting in rhesus macaques (Macaca mulatta)

This study investigated the effects of early exposure to variable parenting style and infant abuse on cerebrospinal fluid (CSF) concentrations of monoamine metabolites and examined the role of monoaminergic function in the intergenerational transmission of infant abuse in rhesus monkeys (Macaca mulatta). Forty-three infants reared by their biological mothers and 15 infants that were cross-fostered at birth and reared by unrelated mothers were followed longitudinally through their first 3 years of life or longer. Approximately half of the infants were reared by abusive mothers and half by nonabusive controls. Abused infants did not differ from controls in CSF concentrations of 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), or 3-methoxy-4-hydroxyphenylgycol (MHPG). Abused infants, however, were exposed to higher rates of maternal rejection, and highly rejected infants had lower CSF 5-HIAA and HVA than low-rejection infants. The abused females who became abusive mothers in adulthood had lower CSF 5-HIAA than the abused females who did not. A similar trend was also observed among the cross-fostered females, suggesting that low serotonergic function resulting from early exposure to high rates of maternal rejection plays a role in the intergenerational transmission of infant abuse.     

HPT axis, CSF monoamine metabolites, suicide intent and depression severity in male suicide attempters

A lower thyroid-stimulating hormone (TSH) response to thyrotropin-releasing hormone (TRH) in depressed women has been associated with violent suicide attempts, suicidal intent, higher lethality and suicide risk. The cerebrospinal fluid (CSF) 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) levels are related to suicidal behaviour. We studied the HPT axis function in twelve male suicide attempters and eight healthy volunteers submitted to lumbar puncture and to TRH test. Suicidal behaviour and depression severity were assessed. There was no association between deltamaxTSH and violent suicidality or subsequent suicide. The deltamaxTSH correlated with CSF HVA in suicide attempters. The plasma T3 showed a negative correlation with the Beck Suicide Intent Scale and the Montgomery Asberg Depression rating scale. Dopaminergic regulatory mechanisms on the thyroid hormone activity may be altered in male suicide attempters.     

Biochemical markers in suicidal patients. Investigations with cerebrospinal fluid amine metabolites and neuroendocrine tests

141 female psychiatric patients, suffering from major depression, schizophrenia, alcohol dependence or adjustment disorder, were investigated for their 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA) and cortisol level in the cerebrospinal fluid (CSF). Dexamethasone suppression tests were also performed in 111 cases, and TRH/TSH tests in 40 subjects. Fifty-two patients were hospitalized following a recent suicide attempt, 18 of which were made using a violent method. The other 34 attempters took tranquilizer or sedative overdoses. CSF 5-HIAA was significantly lower in violent attempters in all 4 diagnostic categories. CSF HVA was higher in those taking drug overdoses, but only in depression (and less markedly in schizophrenia). CSF cortisol did not differ among either diagnostic or suicidal subgroups. Dexamethasone suppression was more frequently abnormal in suicidal patients than in nonattempters, and this difference was more important where the overall nonsuppression rate was lower. Maximal TSH response to TRH showed an inverse correlation with CSF 5-HIAA, and it was lowest in the nonattempter group. The difference between violent suicide attempters and nonattempters in their TSH response was significant. Since these biochemical changes were more or less independent of clinical diagnoses, it seems relevant to explore further the biological background of human aggression and suicide as a separate research direction.     

Electrochemical analysis of hypothalamic serotonin metabolism accompanied by immobilization stress in rats

The effects of stress on serotonin metabolism in the lateral hypothalamic area (LHA) were investigated. Differential pulse voltammetry with a carbon fiber electrode was used to measure 5-hydroxyindoleacetic acid (5-HIAA), the metabolic product of the serotonin (5-HT). High-performance liquid chromatography with electrochemical detection was also used to analyze these compounds in the cerebrospinal fluid (CSF). The peak in voltammogram at an oxidation potential of +230 mV (P3) was identified as 5-HIAA by pharmacological manipulations that are known to affect 5-HT metabolism. A significant increase in 5-HIAA concentration in the LHA was detected after immobilization. An intraperitoneal injection of 5-hydroxytryptophan (5-HTP; a precursor of 5-HT) increased the height of P3, and injection of pargyline prevented the effect of 5-HTP during the course of increasing P3. These results support our previous conclusion that immobilization-induced anorexia might be mediated through activation of serotonergic mechanisms in the LHA.     

Usual values for 5-hydroxy-indol acetic acid and homovanillic acid in cerebrospinal fluid

The aim of this work was to reinvestiagte usual values of neurotransmitter catabolites (5-HIAA and HVA) in CSF, their determination being a current method for studying pathological processes and/or drug induced changes on CNS metabolism. 5-HIAA and HVA have been measured by reverse phase HPLC and electrochemical detection. Since many confounding factors have been identified to modify the concentration of both analytes in CSF, data from 1.480 patients have been revisited with strict exclusion and 323 have been selected. Age dependent variation and asymetric distributions were observed. Age-related usual values ranges were established after identification of outliers by non-parametric analysis. In a group of patients for which repeated CSF collection have been performed for the follow up of acute leukemia, wide and unpredictible individual variations (up to 400 %) of CSF 5-HIAA and HVA concentrations have been observed. These large interindividual and individual variations may explain the numerous discrepancies found in studies investigating the CNS monoamine metabolism, especially when small groups of patients are used. Such observation limits the interpretation of monoamine metabolic for diagnostic purposes without a strict selection of indication.     

Evidence for the role of serotonin in the regulation of slow wave sleep in schizophrenia.

Nocturnal sleep data and cerebrospinal fluid (CSF) concentrations of the biogenic amine metabolites were measured in 20 male schizophrenics. Consistent with other reports of a stage 4 sleep deficit in schizophrenia, measures of stage 4 sleep were low relative to normal reference data. Measures of stage 4 sleep in absolute amounts and corrected for total sleep were positively correlated with CSF concentrations of the serotonin metabolite, 5-hydroxyindole acetic acid (5-HIAA). CSF 5-HIAA was also correlated with measures of stage 3 sleep and total sleep time suggesting that serotonin may modulate the amount of slow wave sleep broadly defined and possibly sleep duration. Total stage 4 time was also correlated with the dopamine metabolite HVA; consequently, the specificity of the finding might be limited. Also, in this study, schizophrenia was used as a particular model for stage 4 deficits; however, the association of measures of stage 4 sleep with CSF levels of 5-HIAA is not thought to be specific to schizophrenia.     

Folate deficiency, biopterin and monoamine metabolism in depression.

Seven (21%) of 34 patients with a severe DSM-III diagnosis of major depression had red-cell folate levels below 150 ng/ml. This subgroup with folate deficiency had significantly lower CSF 5-hydroxyindoleacetic acid (5HIAA) compared to neurological controls. For all depressed patients red-cell folate was significantly correlated with CSF 5HIAA and homovanillic acid (HVA). CSF tetrahydrobiopterin (BH4) was significantly correlated with CSF 5HIAA and HVA and red-cell folate. Our observations provide further evidence of the links between folate, biopterin and monoamine metabolism in depression.