Urinary Δ-aminolevulinic Acid Research Articles

Association between relatively low blood lead levels and urinary δ-aminolevulinic acid concentrations among male workers at a Japanese battery factory.

Whether the known positive association between blood lead (PbB) levels and urinary δ-aminolevulinic acid (ALAU) also exists at relatively low PbB levels (<40μg/dL) remains unclear. We aimed to investigate this association at lower PbB levels. We analyzed data from biannual medical examinations of workers at a Japanese factory from August 2013 to August 2023. We excluded records from female workers and those with missing data, resulting in a dataset consisting of 1396 records from 155 male workers. We employed mixed-effect linear regression models with a random intercept for workers and additional adjustments for age and smoking status. The median PbB level across all the analyzed records was 8μg/dL (range: 1-31μg/dL). Significant positive associations were observed between PbB and ALAU, with a 1-unit increase in natural logarithm-transformed PbB corresponding to a 10.0% increase in ALAU (95% CI, 2.7%-17.9%). Categorized PbB analyses showed a 23.8% increase in ALAU (95% CI, 2.7%-49.2%) for PbB levels at 20-24μg/dL and an 83.1% increase (95% CI, 30.1%-157.7%) for PbB levels ≥25μg/dL, compared with those <5μg/dL. The exposure-response curve analysis indicated a plateau followed by an increasing trend. A positive and nonlinear association between PbB and ALAU levels was observed at relatively low PbB levels.

Pharmacokinetic-pharmacodynamic model of urinary δ-aminolevulinic acid reduction after givosiran treatment in patients with acute hepatic porphyria.

Givosiran, an RNA interference-based therapeutic, is a recent addition to the limited treatment armamentarium for acute hepatic porphyria (AHP). As a small interfering RNA that is selectively taken up in the liver, both the mechanism and targeted delivery create a complex relationship between givosiran pharmacokinetics (PK) and the pharmacodynamic (PD) response. Using pooled data from phase I-III clinical trials of givosiran, we developed a semimechanistic PK/PD model to describe the relationship between predicted liver and RNA-induced silencing complex concentrations of givosiran and the associated reduction in synthesis of δ-aminolevulinic acid (ALA), a toxic heme intermediate that accumulates in patients with AHP, contributing to disease pathogenesis. Model development included quantification of variability and evaluation of covariate effects. The final model was used to assess the adequacy of the recommended givosiran dosing regimen across demographic and clinical subgroups. The population PK/PD model adequately described the time course of urinary ALA reduction with various dosing regimens of givosiran, the interindividual variability across a wide range of givosiran doses (0.035-5mg/kg), and the influence of patient characteristics. None of the covariates tested had a clinically relevant effect on PD response that would necessitate dose adjustment. For patients with AHP, including adults, adolescents, and patients with mild to moderate renal impairment or mild hepatic impairment, the 2.5-mg/kg once monthly dosing regimen of givosiran results in clinically meaningful ALA lowering, reducing the risk for AHP attacks.

Derivative Matrix-Isopotential Synchronous Spectrofluorimetry and Hantzsch Reaction: A Direct Route to Simultaneous Determination of Urinary δ-Aminolevulinic Acid and Porphobilinogen.

Early and sensitive detection of δ-aminolevulinic acid (δ-ALA) and porphobilinogen (PBG) is the cornerstone of diagnosis and effective treatment for acute porphyria. However, at present, the quantifying strategies demand multiple solvent extraction steps or chromatographic approaches to separate δ-ALA and PBG prior to quantification. These methods are both time-consuming and laborious. Otherwise, in conventional spectrofluorimetry, the overlapping spectra of the two analytes cause false diagnosis. To overcome this challenge, we present a two-step approach based on derivative matrix-isopotential synchronous fluorescence spectrometry (DMISFS) and the Hantzsch reaction, realizing the simple and simultaneous detection of δ-ALA and PBG in urine samples. The first step is chemical derivatization of the analytes by Hantzsch reaction. The second step is the determination of the target analytes by combining MISFS and the first derivative technique. The proposed approach accomplishes following advantages: 1) The MISFS technique improves the spectral resolution and resolves severe spectral overlap of the analytes, alleviating tedious and complicated pre-separation processes; 2) First derivative technique removes the background interference of δ-ALA on PBG and vice versa, ensuring high sensitivity; 3) Both the analytes can be determined simultaneously via single scanning, enabling rapid detection. The obtained detection limits for δ-ALA and PBG were 0.04 μmol L−1 and 0.3 μmol L−1, respectively. Within-run precisions (intra and inter-day CVs) for both the analytes were <5%. Further, this study would serve to enhance the availability of early and reliable quantitative diagnosis for acute porphyria in both scientific and clinical laboratories.

Ameliorative effects of nutritional minerals on lead-induced hematological alterations in male Wistar albino rats

The deficiency of essential minerals increases lead absorption and thus aggravates the lead-induced toxic effects. This study was aimed at understanding the ameliorative effect of essential minerals on lead-induced alterations in hematological parameters in rats. To achieve this objective, the study was conducted in 320 male Wistar albino rats, grouped into two, with equal numbers. One of the groups of rats was fed on a mineral-supplemented food referred to as a ‘well-nourished group’ and another group ‘undernourished group’ on food without mineral supplements. Each group of rats was further subdivided into ‘Subjects’ and ‘Controls.’ Subjects of both the groups of rats were exposed to 500 ppm lead acetate up to a period of 300 days (10 months) in drinking water and the role of minerals on lead-induced alterations in hematological parameters was evaluated. A significant decrease (p < 0.001) in hemoglobin (Hb) and δ-aminolevulinic acid dehydratase (δ-ALAD) levels and a significant increase (p < 0.001) in urinary δ-aminolevulinic acid (δ-ALAU) levels were seen in subjects without mineral supplementation compared to those fed on a mineral-enriched diet. A positive correlation was observed between blood lead levels (PbB) and δ-ALAU (r = 0.792) and a negative correlation with Hb (r = −0.926) and δ-ALAD (r = −0.836) in the subjects. These changes were very prominent in the undernourished subjects when compared to the well-nourished subjects. Observations of the present study indicate that mineral supplementation with ongoing lead exposure may help in minimizing the absorption of lead and reduce lead-induced toxic effects.

Relationship between personal-sampled air lead and blood lead in low-lead-exposure workers in Japan to apply multiple regression models determining permissible air lead concentration.

ObjectivesWe investigated the relationship between lead in air (Pb‐A) measured by personal sampling and blood lead (Pb‐B) in workers with relatively low lead exposure to estimate the permissible air concentration of lead corresponding to the biological tolerance value of Pb‐B of 15 µg/dL.MethodsWe collected air samples at a lead‐acid battery factory in Japan by personal sampling devices attached to 32 workers (19 males and 13 females) and measured Pb‐A by a graphite furnace atomic absorption spectrophotometer in 2017‐2020. In addition, we collected information on age, smoking habits, Pb‐B, and urinary δ‐aminolevulinic acid from the records of medical examinations for lead poisoning. Samples were collected two times from four workers, resulting in 36 data sets.ResultsBefore analyses, we excluded four inappropriate data sets. The levels of Pb‐A in the factory and Pb‐B in the workers were almost under the current permissible limits. Multiple regression models showed significant correlations between Pb‐B and Pb‐A, and sex, and borderline significance between Pb‐B and age. Based on them, we calculated Pb‐A corresponding to Pb‐B 15 μg/dL, and obtained similar values to the current occupational exposure limit (OEL) of 30 μg/m3, with slight variation between sex and age.ConclusionThese results validate OEL, although supplementary conditions in terms of sex and age may be necessary.

Reassessment of the threshold of the blood lead level to increase urinary δ-aminolevulinic acid based on their relationship in recent lead workers in Japan.

ObjectivesThe present study investigated the quantitative relationship between blood lead (Pb‐B) and urinary δ⁻aminolevulinic acid (ALA‐U) in lead workers, and examined the Pb‐B level that induces increases in ALA‐U and the corresponding ALA‐U.MethodsWe collected 10 562 data sets on Pb‐B, ALA‐U, age, and smoking habits from 808 workers (771 males and 37 females) who underwent multiple lead poisoning medical examinations at a lead‐acid battery and lead smelting plant in Japan between 1995 and 2018. Females were excluded, and data collected in 169 subjects prior to engaging in lead work were used as the control. Pb‐B and ALA‐U levels were measured by graphite furnace atomic absorption spectrophotometry and high‐performance liquid chromatography respectively.ResultsA significant dose‐response relationship was observed between Pb‐B and ALA‐U based on Pb‐B‐classified observations of increases in ALA‐U values and the prevalence of over‐reference ALA‐U as well as regression analyses independent of smoking habits. The results obtained revealed that the threshold of Pb‐B to increase ALA‐U was 25.1‐35.0 µg/dL based on the significant elevation point of the prevalence of over‐reference ALA‐U and 16.2‐22.3 µg/dL from a 3rd degree regression equation.ConclusionsWe proposed a threshold of Pb‐B to increase ALA‐U of 20 µg/dL and a biologically acceptable value of ALA‐U of 1 mg/L, corresponding to the threshold.

Evaluation of Blood Lead Levels and Their Effects on Hematological Parameters and Renal Function in Iranian Lead Mine Workers

Background: Lead toxicity has become a growing health concern in countries such as Iran. However, little information is available on the assessment and evaluation of the health effects of lead exposure in mine workers. Objectives: The present study assessed the occupational exposure to lead and examine the association of blood lead (PbB) levels with hematological and kidney function parameters in mine workers. Methods: In this matched case-control study, the level of PbB was measured in 100 workers (70 exposed and 30 non-exposed), and then its relationship was evaluated with complete blood count (CBC) parameters, zinc protoporphyrin (ZPP), urea, blood creatinine levels, urinary δ-aminolevulinic acid (ALA), coproporphyrin, and creatinine levels. Results: The results showed a linear and significant relationship between the PbB level and B-ZPP, U-ALA, U-coproporphyrin, and U-creatinine levels in states of PbB levels &gt; 20 μg/dL in a time and dose-dependent manner. A significant relationship was observed between the PbB level and the years of occupational exposure to lead and the B-urea level (P-value &lt; 0.03). Conclusions: Chronic occupational exposure to lead decreased hematocrit, RDW-CV, MCV, MCH, and HGB values but did not significantly change RBC counts. Therefore, a regular assessment of routine blood parameters (such as CBC and ZPP) and renal function indices can be effectively used to monitor the toxic effects of lead exposure.

Blood Lead, Urinary Lead and Urinary δ-Aminolevulinic Acid Levels among Children Living in Kinshasa, D R Congo: A Pilot Biomonitoring Study

Blood Lead, Urinary Lead and Urinary δ-Aminolevulinic Acid Levels among Children Living in Kinshasa, D R Congo: A Pilot Biomonitoring Study

Biomonitoring chronic lead exposure among battery manufacturing workers in Tunisia.

The aim of the study was the biomonitoring of the chronic exposure to Pb by measuring its levels in blood, urine, and hair of battery workers. Blood lead (BPb), urinary lead (UPb), hair lead (HPb), and urinary δ-aminolevulinic acid (UALA) levels were determined for 52 workers in a battery plant and compared to those of 20 non-occupational exposed subjects (controls). BPb and UPb levels were determined by graphite furnace atomic absorption spectrometry (GFAAS). HPb levels were measured by triple quadrupole ICP-MS and UALA levels were determined using cation exchanger column. The measured levels were significantly higher compared to the controls exceeding the OSHA cutoff values (p < 0.01). The GM mean levels of BPb, UPb, UALA, and HPb of workers were 715μgL-1, 331μgL-1, 16.3mgg-1, and 234μgg-1, respectively. The GM mean levels of BPb, UPb, UALA, and HPb of controls were 93.6μgL-1, 36.3μgL-1, 1.9mgg-1, and 1.8μgg-1, respectively. Significant correlations were observed between BPb and UALA (r = 0.630, p = 0.000), UPb and UALA (r = 0.566, p = 0.000), and between BPb and HPb (r = 0.466, p = 0.004). The significant correlation between BPb and HPb suggests the usefulness of hair for assessing occupational exposure particularly when the study area presents medium to high levels of Pb pollution. The association between Pb biomarkers and potential confounding factors revealed significant influence of the occupational factor over smoking and alcohol consumption. The results of this study urge for the reinforcement of the implemented engineering controls and safety measures in order to reduce exposure and to address the health issues related to Pb poisoning.

Derivative matrix-isopotential synchronous spectrofluorimetry: a solution for the direct determination of urinary δ-aminolevulinic acid

The excitation and emission spectra formulated 3D contours, from which isopotential trajectory was selected for the direct detection of urinary δ-aminolevulinic acid, using derivative matrix isopotential synchronous fluorescence spectrometry.

Secret Underlying Unexplained Abdominal Pain, Neurological Symptoms and Intermittent Hypertension: Acute Intermittent Porphyria

Abstract A 21-year-old female patient with abdominal pain, vomiting and constipation was admitted to the hospital with the possible diagnosis of diabetic ketoacidosis. Due to increased abdominal pain and constipation the patient underwent a surgery with the diagnosis of ileus. However, no pathological findings were found in the abdominal organs apart from serous fluid in the abdominal cavity. The patient became hypertensive, tachycardic and had an episode of seizures postoperatively. Neurological manifestations with unexplained abdominal pain indicated a diagnosis of acute intermittent porphyria (AIP). Acute intermittent porphyria diagnosis is based on elevated urinary δ-aminolevulinic acid (ALA) and porphobilinogen (PBG) levels as well as hydroxymethylbilane synthase (HMBS) IVS13-2 A&gt;G heterozygous mutation. Familial Mediterranean Fever (FMF) gene mutations were not confirmed. Porphyria should be considered in the differential diagnosis of patients with recurrent abdominal pain, neurological symptoms and lack of FMF gene polymorphism.

Biological Monitoring and the Occupational Physician

This article aims to introduce biological monitoring, which has been carried out in Japan for 25 years. Biological monitoring in occupational health is an assessment of the overall exposure to chemicals that are present in the workplace through measurement of the appropriate determinants in biological specimens in workers. Lead in blood and urinary δ-aminolevulinic acid in the urine of workers who handle lead, and urinary metabolites of workers who handle 8 kinds of organic solvents, are mandatory measurements. In 2013, insium and compounds, etheylbenzene (only coating workers), and cobalt and inorganic compounds were added to biological monitoring subjects, alongside the ordinal ones of specified chemical substances. Occupational physicians are required to carry out biological monitoring according to standardized protocols in order to correctly utilize biological monitoring results for occupational health management.

The effect of occupational lead exposure on lipid peroxidation, protein carbonylation, and plasma viscosity

The aim of the study was to investigate the influence of occupational lead (Pb) exposure on lipid peroxidation, protein carbonylation, and plasma viscosity in workers. The examined group included 283 healthy male employees of manufacturing facilities using zinc and Pb. The mean blood concentrations of Pb and zinc protoporphyrin as well as the mean urine δ-aminolevulinic acid levels were used as markers of exposure for the examined group. Taking into account the obtained mean values of blood lead level, the examined group was divided into three subgroups. When comparing the control group with the subgroups, Pb exposure markers were significantly elevated in all the three subgroups. Concentrations of conjugated dienes (CD), lipid hydroperoxides, malondialdehyde (MDA), and protein carbonyl groups were also significantly increased. Conversely, the levels of total protein and protein sulfhydryls were significantly decreased in the subgroups compared with the controls. The plasma viscosity was significantly elevated in the subgroups. A dose-response between Pb levels and plasma viscosity was not observed. Pb supposedly elevates MDA and CD in a dose-dependent manner. In conclusion, occupational Pb exposure induces oxidative stress that results in lipid and protein damage. Moreover, Pb-induced oxidative stress is likely the primary factor that elevates plasma viscosity, despite decreased protein levels.

Recurrent porphyria attacks in a Chinese patient with a heterozygous PBGD mutation

We report here the case of a 32-year-old Chinese Han woman who presented with frequent severe abdominal pain, convulsion, numbness and confusion. She also had hypertension, hyponatremia, chronic renal failure, anemia and a high urinary δ-aminolevulinic acid concentration. We identified a heterozygous splicing mutation in intron 11 (IVS11-2A→G) of the porphobilinogen (PBG) deaminase gene (PBGD) in her genomic DNA. This mutation had previously been reported in a North American patient, but was absent from 50 healthy Chinese controls.

Improvement of an HPLC method to determine urinary δ-aminolevulinic acid

OBJECTIVE: The purpose of this study was to evaluate and improve a high performance liquid chromatography (HPLC) methodology to determine urinary δ-aminolevulinic acid (ALA-U) with small volumes of sample. METHOD: The method was based on the formation of a fluorescent compound and subsequent 15-minute chromatographic run. RESULTS: The method shows suitable linearity, precision and recovery. Urine samples showed 1.2 ± 0.9 mg/l (media ± standard deviation) of ALA-U. CONCLUSION: The method was considered suitable for the routine analysis of ALA-U.

Individual susceptibility associated with enzymatic and cytogenetic biomarkers in occupational exposure to inorganic lead

More consideration is given to occupational lead exposure, especially from ecogenetic and molecular epidemiology point of view. Lead causes genotoxic effects and influences some important metabolic pathways by inhibiting key enzymes, a good reason for researchers to assess individual susceptibility through specific biomarkers. The present paper emphasizes the relationship between occupational lead exposure, biochemical indicators (δ-aminolevulinic acid dehydratase), cytogenetic biomarker, hematological indicators (hemoglobin, hematocrit) and frequency of hospitalizations for saturnism. The study comprised 12 male workers occupationally exposed to inorganic lead from a non- ferrous metallurgical factory, Romania. Exposure to inorganic lead was assessed by determination of lead concentration in the workplace and by biotoxicological analyses (blood lead level, urine lead level, urine δ-aminolevulinic acid). Blood δ- aminolevulinic acid dehydratase level was measured. We found a statistically significant correlation between micronucleus score, level of δ-aminolevulinic acid dehydratase and frequency of hospitalizations for lead poisoning. We propose these indicators as an accessible instrument in evaluating individual susceptibility to lead poisoning, more practical than laborious polymorphism genes assessment and less ethically debatable issue.

AAV8-mediated Gene Therapy Prevents Induced Biochemical Attacks of Acute Intermittent Porphyria and Improves Neuromotor Function

Acute intermittent porphyria (AIP), an autosomal dominant hepatic porphyria due to half-normal hydroxymethylbilane synthase (HMB-synthase) activity, is manifested by life-threatening acute neurological attacks that are precipitated by factors that induce heme biosynthesis. The acute attacks are currently treated with intravenous hemin, but a more continuous therapy is needed, particularly for patients experiencing frequent attacks. Thus, a recombinant AAV8-based serotype vector expressing murine HMB-synthase driven by liver-specific regulatory elements was generated and its effectiveness to prevent the biochemical induction of an acute attack was evaluated in an AIP mouse model. Intraperitoneal administration of the adeno-associated viral (AAV) vector resulted in a rapid and dose-dependent increase of HMB-synthase activity that was restricted to the liver. Stable expression of hepatic HMB-synthase was achieved and wild-type or greater levels were sustained for 36 weeks. When heme synthesis was periodically induced by a series of phenobarbital injections, the treated mice did not accumulate urinary delta-aminolevulinic acid (ALA) or porphobilinogen (PBG), indicating that the expressed enzyme was functional in vivo and prevented induction of the acute attack. Further, rotarod performance and footprint analyses improved significantly. Thus, liver-directed gene therapy provided successful long-term correction of the hepatic metabolic abnormalities and improved neuromotor function in the murine model of human AIP.

δ-Aminolevulinic acid dehydratase activity, urinary δ-aminolevulinic acid concentration and zinc protoporphyrin level among people with low level of lead exposure

To evaluate the relationship of delta-aminolevulinic acid dehydratase (ALAD) activity, urinary delta-aminolevulinic acid (ALAU) level and blood zinc protoporphyrin (ZPP) concentration to low blood lead (PbB) levels, these biomarkers were determined for all subjects enrolled from a rural area of southeast China where people had low levels of exposure to lead. The mean values of PbB, ALAD, ALAU and ZPP were 67.11 microg/L (SD: 1.654, range: 10.90-514.04), 339.66 nmol ml(-1)h(-1) (1.419, 78.33-793.13), 20.64 microg/L (1.603, 2.00-326.00), and 0.14 micromol/L (3.437, 0.01-2.26), respectively. ALAD was inversely associated with low levels of PbB. ZPP was inversely related to low levels of PbB but positively related to relatively higher levels of PbB. Alcohol drinking contributed to low ALAD in men. Women had higher ZPP than men. ALAU had no significant association with PbB. In conclusion, ALAD possibly has a non-linear relation with low to moderate levels of PbB. At moderate levels of PbB, ZPP increases with increasing levels of PbB. ALAU is not suitable as an indicator for low levels of lead exposure.

Oral supplementation of gossypin during lead exposure protects alteration in heme synthesis pathway and brain oxidative stress in rats

Objective The objective was to study the efficacy of oral supplementation of gossypin, a flavonoid, during lead exposure in preventive alterations in the heme synthesis pathway, brain oxidation, and tissue lead uptake in rats. Methods Male rats were used for the experiment and were exposed to lead (0.5% in drinking water) or lead plus oral supplementation of gossypin (25 or 100 mg/kg) for 3 wk to determine the preventive effect of gossypin against lead toxicity. Animals were sacrificed after 3 wk for various biochemical variables suggestive of oxidative stress and heme synthesis pathway in addition to the concentration of lead in the blood and brain. Results Exposure to lead produced significant inhibition in the activity of blood δ-aminolevulinic acid dehydratase accompanied by an increase in urinary δ-aminolevulinic acid and the levels of reactive oxygen species. There were significant alterations in the levels of glutathione, thiobarbituric acid-reactive substances, reactive oxygen species, and superoxide dismutase activity on lead exposure. Most of these alterations were significantly prevented by oral coadministration of gossypin, particularly at the dose of 100 mg/kg. Conclusion The antioxidant and moderate chelating properties of oral gossypin suggest a promising role in use either as a nutritional supplement during lead exposure or as a complementary chelating agent during chelation therapy.

Comparative study of genotoxic effects in workers exposed to inorganic lead and low dose irradiation using micronucleus test

This paper presents a case-control study of micronuclei score evaluation as cytogenetic test in male workers exposed to inorganic lead from a non-ferrous metallurgical plant, Romania. Literature data on genotoxic effects of this heavy metal are still matter of discussions. We have compared micronuclei frequency measured from the lymphocytes of both inorganic lead-exposed and radiation-exposed workers as well as their respective matched controls. The study consisted of 60 subjects divided into three groups: lead exposed workers, workers exposed to ionizing radiation and controls. Exposure to inorganic lead was assessed either by determination of lead concentration in the workplace air or by biotoxicological analyses (blood lead level, urine lead level, urine δ-aminolevulinic acid). The results of our investigation showed an increased micronuclei mean score in lead-exposed workers compared to control group (6.0±2.328‰ vs. 2.7±0.978‰, p<0.001). We found that lead produces chromosomal damage comparable to that induced by ionizing radiation (micronuclei mean score 5.55±1.877‰ in subjects exposed to X rays). In conclusion, we propose the use of the micronucleus assay as a screening test for occupationally lead-exposed workers displaying repeated occupational poisoning and pathological outcome.