Neurotoxic effects of nephrotoxic compound diethylene glycol.

CONTEXT: Diethylene glycol (DEG) is an organic compound found in household products but also as an adulterant in medicines by acting as a counterfeit solvent. DEG poisonings have been characterized predominately by acute kidney injury (AKI), but also by delayed neurological sequelae such as decreased reflexes or face and limb weakness. OBJECTIVES: Characterizing the neurological symptoms of DEG poisoning in a subacute animal model would create a clearer picture of overall toxicity and possibly make mechanistic connections between kidney injury and neuropathy. METHODS: Male Wistar-Han rats were orally administered doses of 4 - 6 g/kg DEG every 12 or 24 h and monitored for 7 days. Urine was collected every 12 h and endpoint blood and cerebrospinal fluid (CSF) were collected for a renal plasma panel and total protein estimation, respectively. Motor function tests were conducted before and after treatment. Kidney and brain tissue was harvested for metabolic analysis. RESULTS: Of the 43 animals treated with DEG, 11 developed AKI as confirmed by increased BUN and creatinine levels. Renal and brain DGA accumulation was markedly increased in animals that developed AKI compared to animals without AKI. The total protein content in CSF in animals with kidney injury was markedly elevated compared to control and to treated animals without AKI. Significant decreases in forelimb grip strength and decreases in locomotor and rearing activity were observed in animals with AKI compared to control and to animals without AKI. DISCUSSION: Repeated dosing with DEG in an animal model produced nephrotoxic effects like those in studies with acute DEG administration. The decrease in motor function and increase in CSF protein were only present in animals that developed AKI. CONCLUSIONS: These studies show development of neurotoxicity in this DEG animal model and suggest that neurological symptoms are observed only when DGA accumulation and kidney injury also occur.

Hypertension is associated with worse cognitive function and hippocampal hypometabolism in Alzheimer's disease.

BACKGROUND AND PURPOSE: A growing body of evidence suggests that cardiovascular disease risk factors including hypertension may be linked to sporadic Alzheimer's disease (AD). It is well known that hypertension is associated with cerebrovascular disease and vascular dementia on the basis of vascular remodeling. However, the mechanisms linking hypertension and AD remain unclear. METHODS: We studied 197 patients with AD (86 male; mean age ± SD: 75.8 ± 7.4 years) from the Alzheimer's Disease Neuroimaging Initiative database with (n = 97) and without (n = 100) hypertension. We explored associations between hypertension and clinical, plasma, cerebrospinal fluid and imaging markers of AD pathology in order to elucidate the underlying mechanisms that may link AD and hypertension. RESULTS: We found that patients with AD with hypertension had worse cognitive function (Alzheimer's disease Assessment Scale-cognitive subscale, P = 0.038) and higher neuropsychiatric symptom burden (Neuropsychiatric Inventory Questionnaire, P = 0.016) compared with those without hypertension. Patients with AD with hypertension showed reduced glucose hypometabolism in the right (P < 0.001) and left (P = 0.007) hippocampus. No differences were found in magnetic resonance imaging volumetric measurements, [18 F]florbetapir uptakes, plasma and cerebrospinal fluid between patients with AD with and without hypertension. CONCLUSIONS: Although hypertension is associated with worse cognitive function, behavioural symptoms and hippocampal glucose hypometabolism, it is not associated with evidence of increased amyloid or tau pathology. Effective management of hypertension may potentially have a therapeutic role in the alleviation of symptoms in AD.

Characterizing concentrations of diethylene glycol and suspected metabolites in human serum, urine, and cerebrospinal fluid samples from the Panama DEG mass poisoning.

CONTEXT: Diethylene glycol (DEG) mass poisoning is a persistent public health problem. Unfortunately, there are no human biological data on DEG and its suspected metabolites in poisoning. If present and associated with poisoning, the evidence for use of traditional therapies such as fomepizole and/or hemodialysis would be much stronger. OBJECTIVE: To characterize DEG and its metabolites in stored serum, urine, and cerebrospinal fluid (CSF) specimens obtained from human DEG poisoning victims enrolled in a 2006 case-control study. METHODS: In the 2006 study, biological samples from persons enrolled in a case-control study (42 cases with new-onset, unexplained AKI and 140 age-, sex-, and admission date-matched controls without AKI) were collected and shipped to the Centers for Disease Control and Prevention (CDC) in Atlanta for various analyses and were then frozen in storage. For this study, when sufficient volume of the original specimen remained, the following analytes were quantitatively measured in serum, urine, and CSF: DEG, 2-hydroxyethoxyacetic acid (HEAA), diglycolic acid, ethylene glycol, glycolic acid, and oxalic acid. Analytes were measured using low resolution GC/MS, descriptive statistics calculated and case results compared with controls when appropriate. Specimens were de-identified so previously collected demographic, exposure, and health data were not available. The Wilcoxon Rank Sum test (with exact p-values) and bivariable exact logistic regression were used in SAS v9.2 for data analysis. RESULTS: The following samples were analyzed: serum, 20 case, and 20 controls; urine, 11 case and 22 controls; and CSF, 11 samples from 10 cases and no controls. Diglycolic acid was detected in all case serum samples (median, 40.7 mcg/mL; range, 22.6-75.2) and no controls, and in all case urine samples (median, 28.7 mcg/mL; range, 14-118.4) and only five (23%) controls (median, < Lower Limit of Quantitation (LLQ); range, < LLQ-43.3 mcg/mL). Significant differences and associations were identified between case status and the following: 1) serum oxalic acid and serum HEAA (both OR = 14.6; 95% C I = 2.8-100.9); 2) serum diglycolic acid and urine diglycolic acid (both OR > 999; exact p < 0.0001); and 3) urinary glycolic acid (OR = 0.057; 95% C I = 0.001-0.55). Two CSF sample results were excluded and two from the same case were averaged, yielding eight samples from eight cases. Diglycolic acid was detected in seven (88%) of case CSF samples (median, 2.03 mcg/mL; range, < LLQ, 7.47). DISCUSSION: Significantly elevated HEAA (serum) and diglycolic acid (serum and urine) concentrations were identified among cases, which is consistent with animal data. Low urinary glycolic acid concentrations in cases may have been due to concurrent AKI. Although serum glycolic concentrations among cases may have initially increased, further metabolism to oxalic acid may have occurred thereby explaining the similar glycolic acid concentrations in cases and controls. The increased serum oxalic acid concentration results in cases versus controls are consistent with this hypothesis. CONCLUSION: Diglycolic acid is associated with human DEG poisoning and may be a biomarker for poisoning. These findings add to animal data suggesting a possible role for traditional antidotal therapies. The detection of HEAA and diglycolic acid in the CSF of cases suggests a possible association with signs and symptoms of DEG-associated neurotoxicity. Further work characterizing the pathophysiology of DEG-associated neurotoxicity and the role of traditional toxic alcohol therapies such as fomepizole and hemodialysis is needed.

Effect of chlorpromazine treatment on monoamine metabolite levels in cerebrospinal fluid of psychotic patients.

Levels of HVA, MOPEG and 5-HIAA in cerebrospinal fluid (CSF) from psychotic men and women with a schizophrenic symptomatology were measured by mass fragmentography. Measurements were made before, 2 and 4 weeks after treatment with chlorpromazine (CPZ) which was given randomly in doses of 200, 400 or 600 mg per day. Before treatment there were positive correlations between the levels of HVA and 5-HIAA in both sexes. During CPZ treatment HVA was significantly elevated, whereas MOPEG and 5-HIAA were reduced. There was a tendency towards tolerance to CPZ's effect on HVA during treatment but a significant effect persisted after 4 weeks. No indication of tolerance to the effects on MOPEG or 5-hiaa was found. There were the same tendencies for the elevations of the HVA/MOPEG and HVA/5-HIAA ratios. The changes in HVA, MOPEG, 5-HIAA, HVA/MOPEG and HVA/5-HIAA were related to dose of CPZ in men but not in women. The bidirectional change of the different metabolites in CSF during CPZ treatment excluses a general and non-specific mechanism for the metabolite changes. The HVA elevation is in accordance with previous results in animals and man, and is presumably related to blockade of central dopamine receptors. Possible mechanisms for the effects on MOPEG and 5-HIAA are discussed.