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PubMedDate not supplied

The accumulation of mono-2-ethylhexylphthalate (MEHP) during storage of whole blood and plasma.

The accumulation of the plasticizer di-2-ethylhexylphthalate (DEHP) in blood and blood components has been of considerable concern for some time. We have followed the accumulation of DEHP and one of its major metabolities, mono-2-ethylhexylphthalate (MEHP) during storage of whole blood, platelet-rich plasma, platelet concentrates, and platelet-poor plasma for periods ranging from 72 hours to four weeks. Both phthalates showed a progressive increase in concentration with time. While the levels of DEHP were much greater than those of MEHP, there was nonetheless a significant and continual increase in MEHP in all preparations. The highest concentrations of both DEHP and MEHP were found in the platelet-poor plasma, indicating that platelets do not have a major role in the accumulation of the phthalates in blood. The accumulation of MEHP was shown to be a direct result of the metabolism of DEHP by plasma protein(s) rather than leaching from the blood bag.

Blood Platelets↗
PubMedDate not supplied

Di-2-ethylhexyl phthalate (DEHP) and mono-2-ethylhexyl phthalate (MEHP) accumulation in whole blood and red cell concentrates.

Plasma DEHP concentrations were measured weekly in whole blood and red cell concentrates (RCC) during 21 days of storage in standard CPD within PL-130 blood bags. In addition, DEHP and MEHP accumulation patterns were investigated in blood stored for 42 days in modified CPD with adenine within PL-146 and BB-69 storage containers. Total per-unit plasma DEHP of RCC units was 49 to 71 per cent of the total in plasma of whole blood units (PL-130). From 28 to 42 days, mean DEHP levels were 12 to 19 per cent higher in whole blood stored in PL-146 than in BB-69. Although MEHP was not found in any blood bag plastic, MEHP accumulated in plasma during whole blood storage. MEHP concentrations were 2.8 to 3.8 times higher in plasma stored in BB-69 than in PL-146. It is postulated that MEHP arises from hydrolysis of DEHP by plasma lipase, even in frozen plasma sample, and that the rate of this reaction is influenced by blood bag plastic surface characteristics.

Blood Preservation↗
PubMed2026

Elevated phthalate exposure and metabolic susceptibility increased breast cancer risk: A 20-y follow-up study in Taiwan.

Widely used phthalates, especially di-(2-ethylhexyl) phthalate (DEHP), increase breast cancer risk in experimental animals and humans, but long-term follow-up evidence of its human breast carcinogenicity remains inconclusive. This nested case-control study included 119 invasive breast cancer cases and 245 matched controls from a longitudinal cohort of 11,923 women recruited in 1991-1992 and followed to 2010 in Taiwan. Urine samples at baseline and follow-up visit were tested for 11 metabolites of seven phthalates using LC-ESI-MS/MS. DEHP metabolism susceptibility was evaluated by the percentage of mono-2-ethylhexyl phthalate (MEHP%) in the sum of five DEHP metabolites (∑DEHP). Odds ratios (ORs) with 95% CI from conditional logistic regression were used to examine risk predictors. DEHP was the only phthalate significantly associated with breast cancer risk. Risk increased significantly with elevated urinary levels of ∑DEHP (> 0.381 μmol/g creatinine, OR = 1.71, 95% CI = 1.02 to 2.43), MEHP (> 0.022 μmol/g creatinine, OR = 1.87, 95% CI = 1.07 to 3.25), and MEHP% (> 6.7%, OR = 1.65, 95% CI = 0.96 to 2.82). Elevated ∑DEHP and MEHP% combined with early menarche (≤ 14 years) was associated with further increased risk (OR = 7.52, 95% CI = 2.68 to 21.05). The intraclass correlation coefficient between paired baseline and follow-up samples of 152 women was 0.06 for ∑DEHP and 0.31 for MEHP%. High DEHP exposure, high MEHP%, and early menarche were associated with increased breast cancer risk. MEHP% was a better biomarker for DEHP metabolism.

Humans↗
PubMedDate not supplied

Formation of mono(ethylhexyl)phthalate from di(ethylhexyl)phthalate in human plasma stored in PVC bags and its presence in fractionated plasma proteins.

The formation of mono(ethylhexyl)phthalate (MEHP) from di(ethylhexyl)phthalate in human plasma stored in bags of polyvinylchloride has been studied. Substantial amounts were formed and in ten bags from 4 to 56microgram/ml were found. After 2 weeks at room temperature the concentration of MEHP had increased to values between 27 and 79 microgram/ml. However, MEHP was also disappearing as shown in a recovery experiment. Of the fractionated proteins albumin contained MEHP in amounts from less than 3 to 290 microgram/g.

Chemical Fractionation↗
PubMedDate not supplied

Metabolism and tissue distribution of mono-2-ethylhexyl phthalate in the rat.

The absorption, distribution and metabolic excretion of mono-2-ethylhexyl [7-14C]phthalate (MEHP) were studied in the rat. This compound was readily absorbed from the gastrointestinal tract. Radioactivity following intravenous administration of 14C-MEHP was rapidly distributed in all tissues, with the highest levels occurring in the liver, kidney, and urinary bladder. Excretion of radioactivity was rapid and approximately 80% of the dose was eliminated 24 hr after oral administration, 72% in the urine and 8% in feces. MEHP was extensively metabolized after oral administration, and the major urinary metabolites were identified as an alcohol, a ketone, and an acid resulting from the side-chain oxidation of MEHP. A trace of o-phthalic acid was also identified.

Animals↗
PubMedDate not supplied

Metabolism of di-2-ethylhexyl phthalate by subcellular fractions from rainbow trout liver.

Trout liver homogenates metabolized di-2-ethylhexyl phthalate (DEHP) to monoethylhexyl phthalate (MEHP) without added NADPH and to MEHP and more polar metabolites with added NADPH. Both hydrolysis and oxidative metabolism of DEHP were inhibited by piperonyl butoxide. The 10,000g pellet, 100,000g pellet and 100,000g supernatant fraction from liver homogenates all catalyzed the hydrolysis of DEHP and all but the 100,000g supernatant fraction showed the shift to more polar metabolites with added NADPH; serum also catalyzed the hydrolysis of DEHP. Measurement of the microsomal marker, glucose 6-phosphatase, and the mitochondrial marker, succinic dehydrogenase, revealed that DEHP-hydrolytic activity was associated with microsomes and the 100,000g supernatant fraction, whereas DEHP oxidation was associated only with microsomes.

Animals↗