Manganese in long term paediatric parenteral nutrition

Signaling Pathways Involved in Manganese-Induced Neurotoxicity

Manganese (Mn) is an essential trace element, but insufficient or excessive bodily amounts can induce neurotoxicity. Mn can directly increase neuronal insulin and activate insulin-like growth factor (IGF) receptors. As an important cofactor, Mn regulates signaling pathways involved in various enzymes. The IGF signaling pathway plays a protective role in the neurotoxicity of Mn, reducing apoptosis in neurons and motor deficits by regulating its downstream protein kinase B (Akt), mitogen-activated protein kinase (MAPK), and mammalian target of rapamycin (mTOR). In recent years, some new mechanisms related to neuroinflammation have been shown to also play an important role in Mn-induced neurotoxicity. For example, DNA-sensing receptor cyclic GMP-AMP synthase (cCAS) and its downstream signal efficient interferon gene stimulator (STING), NOD-like receptor family pyrin domain containing 3(NLRP3)-pro-caspase1, cleaves to the active form capase1 (CASP1), nuclear factor κB (NF-κB), sirtuin (SIRT), and Janus kinase (JAK) and signal transducers and activators of the transcription (STAT) signaling pathway. Moreover, autophagy, as an important downstream protein degradation pathway, determines the fate of neurons and is regulated by these upstream signals. Interestingly, the role of autophagy in Mn-induced neurotoxicity is bidirectional. This review summarizes the molecular signaling pathways of Mn-induced neurotoxicity, providing insight for further understanding of the mechanisms of Mn.

Exposure of preterm neonates to toxic metals during their stay in the Neonatal Intensive Care Unit and its impact on neurodevelopment at 2 months of age

BACKGROUND

Premature neonates might be exposed to toxic metals during their stay in the neonatal intensive care unit (NICU), which could adversely affect neurodevelopment; however, limited evidence is available. The present study was therefore designed to assess the exposure to mercury, lead, cadmium, arsenic, and manganese of preterm neonates who received total parenteral nutrition (TPN) and/or red blood cell (RBC) transfusions during their NICU stay and the risk of neurodevelopment delay at the age of 2 months.

METHODS

We recruited 33 preterm neonates who required TPN during their NICU admission. Blood samples were collected for metal analysis at two different time points (admission and before discharge). Metals in the daily TPN received by preterm neonates were analyzed. Neurodevelopment was assessed using the Ages and Stages Questionnaire Edition 3 (ASQ-3).

RESULTS

All samples of TPN had metal contamination: 96% exceeded the critical arsenic limit (0.3 μg/kg body weight/day); daily manganese intake from TPN for preterm neonates exceeded the recommended dose (1 µg/kg body weight) as it was added intentionally to TPN solutions, raising potential safety concerns. All samples of RBC transfusions exceeded the estimated intravenous reference dose for lead (0.19 µg/kg body weight). Levels of mercury, lead and manganese in preterm neonates at discharge decreased 0.867 µg/L (95% CI, 0.76, 0.988), 0.831 (95%CI, 0.779, 0.886) and 0.847 µg/L (95% CI, 0.775, 0.926), respectively. A decrease in ASQ-3-problem solving scores was associated with higher levels of blood lead in preterm neonates taken at admission (ß = -0.405, 95%CI = -0.655, -0.014), and with plasma manganese (ß = -0.562, 95%CI = -0.995, -0.172). We also observed an association between decreased personal social domain scores with higher blood lead levels of preterm neonates before discharge (ß = -0.537, 95%CI = -0.905, -0.045).

CONCLUSION

Our findings provide evidence to suggest negative impacts on the neurodevelopment at 2 months of preterm infants exposed to certain metals, possibly related to TPN intake and/or blood transfusions received during their NICU stay. Preterm neonates may be exposed to levels of metals in utero.

Hypermanganesemia-Induced Cerebral Toxicity Mimicking an Acute Ischemic Stroke: A Case Report and Review of Overlapping Pathologies

Objective: To review and consider risk factors associated with the accumulation of and toxicity from manganese in patients receiving total parenteral nutrition (TPN). Case Summary: A 66-year-old female presented to the emergency department with right facial and arm weakness that initiated 1 hour prior to admission. Past medical history includes oral cancer with chronic aspiration and gastroparesis secondary to chemotherapy, TPN for 9 months, and a previous episode of right facial and arm parasthesias due to hypertensive emergency 4 years prior. The patient was assigned a National Institutes of Health Stroke Scale score of 6, cleared of an intracranial hemorrhage on imaging, and was administered tPA (tissue plasminogen activator) for an acute ischemic stroke after managing her hypertension to <185/110 mm Hg. Resolution of symptoms occurred within 24 hours. A magnetic resonance imaging of the patient's brain 24-hours post-tPA indicated an increased signal density in the globus pallidus, which in turn is linked with encephalopathy and has been described as a marker for hypermanganesemia. Discussion: Manganese is an essential trace element with a critical role in numerous physiologic functions. Though readily obtained from dietary sources and rarely causing issue, manganese provided to patients via TPN may result in toxicities. Though the presentation of neurotoxicities associated with TPN-delivered manganese has been previously documented, the clinical presentation of toxicity has never mimicked an acute ischemic stroke. Conclusion: Though an evaluation of overlapping pathologies is warranted, this patient's clinical presentation of manganese toxicity mimicked an acute ischemic stroke and resulted in the administration of a fibrinolytic. A more comprehensive appreciation of the implications of trace elements is demanded of clinicians.

Manganese Exposure and Cognition Across the Lifespan: Contemporary Review and Argument for Biphasic Dose-Response Health Effects

Manganese (Mn) is both an essential micronutrient and potential neurotoxicant. This dual role underlies a growing body of literature demonstrating that Mn exhibits a biphasic dose-response relationship with neurocognitive outcomes. We reviewed recent epidemiologic studies from 2007 to 2016 that investigated the relationship between Mn exposure and cognitive outcomes across the lifespan: early life, school-aged children, and adulthood. In total, 27 research articles were included in this review: 12 pediatric and 15 adult studies (10 occupational and five environmental exposures). The majority of these studies provided evidence of the negative effects of Mn exposure on cognition. The pediatric literature provides evidence that both high and low levels of Mn are negatively associated with intellectual development. Future Mn research should include examination of non-linear relationships and multiple neurotoxicants across the lifespan and particularly during critical developmental windows.

Perinatal manganese exposure and hydroxyl radical formation in rat brain

The present study was designed to investigate the role of pre- and postnatal manganese (Mn) exposure on hydroxyl radical (HO^•) formation in the brains of dopamine (DA) partially denervated rats (Parkinsonian rats). Wistar rats were given tap water containing 10,000 ppm manganese chloride during the duration of pregnancy and until the time of weaning. Control rat dams consumed tap water without added Mn. Three days after birth, rats of both groups were treated with 6-hydroxydopamine at one of three doses (15, 30, or 67 µg, intraventricular on each side), or saline vehicle. We found that Mn content in the brain, kidney, liver, and bone was significantly elevated in dams exposed to Mn during pregnancy. In neonates, the major organs that accumulated Mn were the femoral bone and liver. However, Mn was not elevated in tissues in adulthood. To determine the possible effect on generation of the reactive species, HO^• in Mn-induced neurotoxicity, we analyzed the contents of 2.3- and 2.5-dihydroxybenzoic acid (spin trap products of salicylate; HO^• being an index of in vivo HO^• generation), as well as antioxidant enzyme activities of superoxide dismutase (SOD) isoenzymes and glutathione S-transferase (GST). 6-OHDA-depletion of DA produced enhanced HO^• formation in the brain tissue of newborn and adulthood rats that had been exposed to Mn, and the latter effect did not depend on the extent of DA denervation. Additionally, the extraneuronal, microdialysate, content of HO^• in neostriatum was likewise elevated in 6-OHDA-lesioned rats. Interestingly, there was no difference in extraneuronal HO^• formation in the neostriatum of Mn-exposed versus control rats. In summary, findings in this study indicate that Mn crosses the placenta but in contrast to other heavy metals, Mn is not deposited long term in tissues. Also, damage to the dopaminergic system acts as a “trigger mechanism,” initiating a cascade of adverse events leading to a protracted increase in HO^• generation, and the effects of Mn and 6-OHDA are compounded. Moreover, HO^• generation parallels the suppression of SOD isoenzymes and GST in the brains of rats lesioned with 6-OHDA and/or intoxicated with Mn—the most prominent impairments being in frontal cortex, striatum, and brain stem. In conclusion, ontogenetic Mn exposure, resulting in reactive oxygen species, HO^• formation, represents a risk factor for dopaminergic neurotoxicity and development of neurodegenerative disorders.

Manganese in human parenteral nutrition: considerations for toxicity and biomonitoring

The iatrogenic risks associated with excessive Mn administration in parenteral nutrition (PN) patients are well documented. Hypermanganesemia and neurotoxicity are associated with the duration of Mn supplementation, Mn dosage, as well as pathological conditions, such as anemia or cholestasis. Recent PN guidelines recommend the biomonitoring of patients if they receive Mn in their PN longer than 30 days. The data in the literature are conflicting about the method for assessing Mn stores in humans as a definitive biomarker of Mn exposure or induced-neurotoxicity has yet to be identified. The biomonitoring of Mn relies on the analysis of whole blood Mn (WB Mn) levels, which are highly variable among human population and are not strictly correlated with Mn-induced neurotoxicity. Alterations in dopaminergic (DAergic) and catecholaminergic metabolism have been studied as predictive biomarkers of Mn-induced neurotoxicity. Given these limitations, this review addresses various approaches for biomonitoring Mn exposure and neurotoxic risk.

Evaluation of neurobehavioral and neuroinflammatory end-points in the post-exposure period in rats sub-acutely exposed to manganese

Manganese (Mn) can cause manganism, a neurological disorder similar to Parkinson' Disease (PD). The neurobehavioral and neuroinflammatory end-points in the Mn post exposure period have not been studied yet. Rats were injected on alternate days with 8 doses of MnCl2 (25mg/kg) or saline, then euthanized 1, 10, 30 or 70 days following the last dose. Whole-blood (WB) (p<0.05), urine (p<0.05) and brain cortical (p<0.0001) Mn levels were significantly increased 24h after the last dose. Decreases in the rats' ambulation were noted 1, 10 and 30 days after the last Mn dose (p<0.001; p<0.05; p<0.001, respectively) and also in the rearing activity at the four time-points (p<0.05). Cortical glial fibrillary acid protein immunoreactivity (GFAP-ir) was significantly increased at 1, 10, 30 (p<0.0001) and 70 (p<0.001) days after the last Mn dose, as well as tumor necrosis α (TNF-α) levels (p<0.05) but just on day 1. Taken together, the results show that, during the 70-day clearance phase of Mn, the recovery is not immediate as behavioral alterations and neuroinflammation persist long after Mn is cleared from the cortical brain compartment.

Manganese promotes increased formation of hydrogen peroxide by activated human macrophages and neutrophils in vitro

Although pro-inflammatory mechanisms have been implicated in the pathogenesis of manganese (Mn²⁺)-related neurological and respiratory disorders, relatively little is known about the potential of this metal to interact pro-oxidatively with human phagocytes. The primary objective of the current study was to investigate the effects of Mn²⁺ as MnCl₂ (0.5-100 µM) on the generation of the reactive oxygen species (ROS), superoxide, hydrogen peroxide (H₂O₂), and hypohalous acids by isolated human blood neutrophils and monocyte-derived macrophages following activation of these cells with the chemotactic tripeptide, FMLP (1 µM), or the phorbol ester, PMA (25 ng/mL). Generation of ROS was measured using the combination of oxygen consumption, lucigenin/luminol-enhanced chemiluminescence, spectrofluorimetric detection of oxidation of 2,7-dichlorodihydrofluorescein, radiometric assessment of myeloperoxidase (MPO)-mediated protein iodination, release of MPO by ELISA, and spectrophotometric measurement of nitrite formation. Treatment of activated neutrophils with either FMLP or PMA resulted in significantly decreased reactivity of superoxide in the setting of increased formation of H₂O₂ and MPO-mediated iodination, with no detectable effects on either oxygen consumption or MPO release. Similar effects of the metal with respect to superoxide reactivity and H₂O₂ formation were observed with activated macrophages, while generation of NO was unaffected. Taken together with the findings of experiments using cell-free ROS-generating systems, these observations are compatible with a mechanism whereby Mn²⁺, by acting as a superoxide dismutase mimetic, increases the formation of H₂O₂ by activated phagocytes. If operative in vivo, this mechanism may contribute to the toxicity of Mn²⁺.

Dystonia with brain manganese accumulation resulting from SLC30A10 mutations: a new treatable disorder

Background

The first gene causing early-onset generalized dystonia with brain manganese accumulation has recently been identified. Mutations in the SLC30A10 gene, encoding a manganese transporter, cause a syndrome of hepatic cirrhosis, dystonia, polycythemia, and hypermanganesemia.

Methods

We present 10-year longitudinal clinical features, MRI data, and treatment response to chelation therapy of the originally described patient with a proven homozygous mutation in SLC30A10.

Results

The patient presented with early-onset generalized dystonia and mild hyperbilirubinemia accompanied by elevated whole-blood manganese levels. T1-sequences in MRI showed hyperintensities in the basal ganglia and cerebellum, characteristic of manganese deposition. Treatment with intravenous disodium calcium edetate led to clinical improvement and reduction of hyperintensities in brain imaging.

Conclusions

We wish to highlight this rare disorder, which, together with Wilson's disease, is the only potentially treatable inherited metal storage disorder to date, that otherwise can be fatal as a result of complications of cirrhosis. © 2012 Movement Disorder Society

Parenteral nutrition-associated cholestasis: an American Pediatric Surgical Association Outcomes and Clinical Trials Committee systematic review

OBJECTIVE

The aim of this study was to review evidence-based data addressing key clinical questions regarding parenteral nutrition-associated cholestasis (PNAC) and parenteral nutrition-associated liver disease (PNALD) in children.

DATA SOURCE

Data were obtained from PubMed, Medicine databases of the English literature (up to October 2010), and the Cochrane Database of Systematic Reviews.

STUDY SELECTION

The review of PNAC/PNALD has been divided into 4 areas to simplify one's understanding of the current knowledge regarding the pathogenesis and treatment of this disease: (1) nonnutrient risk factors associated with PNAC, (2) PNAC and lipid emulsions, (3) nutritional (nonlipid) considerations in the prevention of PNAC, and (4) supplemental medications in the prevention and treatment of PNAC.

RESULTS

The data for each topic area relevant to the clinical practice of pediatric surgery were reviewed, evaluated, graded, and summarized.

CONCLUSIONS

Although the conditions of PNAC and PNALD have been well recognized for more than 30 years, only a few concrete associations and treatment protocols have been established.

Optimisation of whole blood and plasma manganese assay by ICP-MS without use of a collision cell

BACKGROUND

Manganese (Mn) toxicity has been reported in patients receiving total parenteral nutrition. To avoid unnecessary exposure it is recommended by NICE (National Institute for Clinical Excellence) that blood Mn concentrations are monitored. The aim of the study was to develop a method using inductively coupled plasma mass spectrometry (ICP-MS) for the reliable determination of Mn in plasma and whole blood, as indices of acute and chronic exposure.

METHODS

Whole blood and plasma samples were prepared by appropriate dilution (diluent containing 0.005% Triton X-100, 0.2% propan-2-ol, 0.2% butan-1-ol and 1% nitric acid) addition of an internal standard gallium, followed by centrifugation to remove cell debris. Thermo Fisher Scientific ExCell and X Series ICP-MS instruments were used to define and correct for polyatomic interference on Mn assay.

RESULTS

Mn was quantified at mass 55 using aqueous calibration and the polyatomic interference from FeH was successfully eliminated by modified (Xt) skimmer cones but not with the collision cell (collision gas 7% H2 in He, flow rate 4-7 mL/min). The assay was validated showing good precision, limit of detection and percentage recovery. Good agreement was observed with the All Laboratory Trimmed Mean of External Quality Assurance samples y (in house)=1.1 (ALTM)-45.0 between values of 250 and 750 nmol/L.

CONCLUSIONS

A method has been developed using ICP-MS for the analysis of whole blood and plasma Mn incorporating a novel method of eliminating interference by utilizing the different geometries of the Xt interface cones. The procedure is simple and robust with good precision and recovery over a wide dynamic range.

Dosing and monitoring of trace elements in long-term home parenteral nutrition patients

BACKGROUND

Trace elements (TEs) dosing and monitoring in home parenteral nutrition (PN) patients vary with their underlying conditions.

METHODS

This retrospective observational study evaluated parenteral TE dosing, serum TE concentrations and monitoring, and dose-concentration relationships between TE doses and serum TE concentrations in 26 adult and adolescent home PN patients.

RESULTS

There was a total of 40,493 PN days. Average parenteral zinc doses of 9.1 mg/d and 7.6 mg/d resulted in the majority of serum zinc concentrations (90%) within normal range in patients with and without short bowel syndrome (SBS), respectively. Selenium at about 70 mcg/d resulted in about 60% of serum selenium concentrations within normal range, with 38% of values below normal in patients with and without SBS alike. Copper at 1 mg/d resulted in 22.5% of serum copper concentrations above the normal range. The majority of serum manganese (94.6%) and chromium (96%) concentrations were elevated. Serum TE concentrations were infrequently monitored. Significant relationships existed between doses and serum concentrations for zinc (P < .0001), manganese (P = .012), and chromium (P < .0001) but not for selenium or copper.

CONCLUSIONS

TE doses in home PN should be individualized and adjusted based on regular monitoring of TE status. In long-term home PN patients, higher zinc and selenium doses may be necessary to maintain their normal serum concentrations. Lower copper doses and restrictions of manganese and chromium supplementation may be needed to avoid their accumulation. Relationships between TE doses and serum TE concentrations vary for each TE and underlying clinical conditions.

Effect of prenatal manganese intoxication on [(3)H]glucose uptake in the brain of rats lesioned as neonates with 6-hydroxydopamine

In the present study we examined the effects of prenatal manganese (Mn) intoxication on [(3)H]glucose uptake in the brain of rats lesioned as neonates with 6-hydroxydopamine (6-OHDA). MnCl(2) . 4H(2)O (10,000 ppm) was added to the drinking water of pregnant Wistar rats for the duration of pregnancy. On the day of parturition, Mn was discontinued as an additive to the drinking water. The control group consisted of rats that consumed water without Mn. Three days after birth, rats in both groups (control and Mn) were pretreated with desipramine hydrochloride (20 mg/kg) and pargyline hydrochloride (50 mg/kg) and injected bilaterally icv with one of three doses of 6-OHDA hydrobromide (15 mug, 30 mug or 67 mug base form in saline on each side) or with saline (control). 6-[(3)H]-D-glucose (500 muCi/kg, ip) was administered to male offspring in adulthood; after 15 min, brain specimens were taken (frontal cortex, hippocampus, striatum, thalamus with hypothalamus, pons and cerebellum) for determination of radioactivity in a liquid scintillation counter. Low dose 6-OHDA (15 mug icv) increased [(3)H]glucose uptake in all brain regions (p < 0.05) in both control and Mn-intoxicated animals. In rats lesioned with a moderate dose of 6-OHDA (30 mug icv), [(3)H]glucose uptake was unaltered in both control and Mn-exposed rats. High dose 6-OHDA (67 mug icv) reduced [(3)H]glucose uptake in all brain regions of Mn-exposed rats (except for cerebellum) compared with the saline group (all, p < 0.05). There was no change in regional brain uptake of [(3)H]glucose in control rats. In conclusion, this study shows that mild neuronal insult (15 mug icv 6-OHDA) increased glucose uptake in the brain while severe damage (concomitant 60 mug icv 6-OHDA and Mn treatment) significantly diminished this process.

Manganese exposure among smelting workers: blood manganese-iron ratio as a novel tool for manganese exposure assessment

Unexposed control subjects (n = 106), power distributing and office workers (n = 122), and manganese (Mn)-exposed ferroalloy smelter workers (n = 95) were recruited to the control, low and high groups, respectively. Mn concentrations in saliva, plasma, erythrocytes, urine and hair were significantly higher in both exposure groups than in the controls. The Fe concentration in plasma and erythrocytes, however, was significantly lower in Mn-exposed workers than in controls. The airborne Mn levels were significantly associated with Mn/Fe ratio (MIR) of erythrocytes (eMIR) (r = 0.77, p < 0.01) and plasma (pMIR) (r = 0.70, p < 0.01). The results suggest that the MIR may serve as a useful biomarker to distinguish Mn-exposed workers from the unexposed, control population.

The use of magnetic resonance imaging (MRI) in the study of manganese neurotoxicity

Manganese (Mn), an element found in many foods, is an important and essential nutrient for proper health and maintenance. It is toxic in high doses, however, and exposure to excessive levels can result in the onset of a neurological disorder similar to, but distinct from, Parkinson's disease. Historically, Mn neurotoxicity was most commonly associated with various occupations, such as Mn mining, welding and steel production. More recently, increases in both blood and brain Mn levels have been observed in persons with liver disease or those receiving prolonged parenteral nutrition. Additionally, rodent data suggest that iron deficiency and anemia may be risk factors for Mn neurotoxicity. Clinically, brain Mn accumulation can be monitored in vivo using non-invasive magnetic resonance imaging (MRI) due to the paramagnetic nature of this element. Indeed, MRI has been used in a variety of settings to evaluate the brain Mn deposition in various populations. This review focuses on the use of MRI technology in studies related specifically to Mn neurotoxicity. Thus, we will examine reports using MRI to confirm brain Mn accumulation in human populations, and conclude with data from non-human primate and rodent models of Mn neurotoxicity.

Intestinal failure-associated liver disease: what do we know today?

Intestinal failure-associated liver disease develops in 40% to 60% of infants who require long-term total parenteral nutrition (TPN) for intestinal failure and 15% to 40% of adults on home parenteral nutrition. The clinical spectrum includes hepatic steatosis, cholestasis, cholelithiasis, and hepatic fibrosis. Progression to biliary cirrhosis and the development of portal hypertension and liver failure occurs in a minority but is more common in infants and neonates than in adults. The pathogenesis is multifactorial. In infants it is related to prematurity, low birth weight, duration of PN, short bowel syndrome requiring multiple laparotomies, and recurrent sepsis. Other important mechanisms include lack of enteral feeding, which leads to reduced gut hormone secretion; reduction of bile flow and biliary stasis, which leads to the development of cholestasis; and biliary sludge and gallstones, which exacerbate hepatic dysfunction. In adults, IFALD is less common and related to age, length of time on PN, total caloric intake, and lipid or glucose overload. In preterm infants, a deficiency of taurine or cysteine may play a role, whereas in both adults and children, choline deficiency may exacerbate IFALD. Lipid emulsions, choline deficiency, and manganese toxicity are associated with both hepatic steatosis and cholestasis in adults and children. Management strategies for the prevention of intestinal failure-induced liver disease include early enteral feeding, a multidisciplinary approach to the management of parenteral nutrition, and aseptic catheter techniques to reduce sepsis. The addition of choline, taurine, and cysteine to PN solutions may also play a role. Oral administration of ursodeoxycholic acid may improve bile flow and reduce gallbladder stasis. Survival after either isolated small bowel or combined liver and small bowel transplantation is approximately 50% at 5 years, making this an acceptable therapeutic option in adults and children with irreversible liver and intestinal failure.

Changes in manganese and lead in the environment and young children associated with the introduction of methylcyclopentadienyl manganese tricarbonyl in gasoline--preliminary results

A 4-year longitudinal study is being conducted to evaluate potential changes to the environment and exposure of young children associated with the introduction of methylcyclopentadienyl manganese tricarbonyl (MMT) into Australia in 2001. The cohort consists of 57 females and 56 males, with an age range of 0.29-3.9 years. Samples are collected every 6 months from children in residences located at varying distances from major traffic thoroughfares in Sydney. Environmental samples include air, house, and daycare center dustfall, soil, dust sweepings, and gasoline; samples from the children include blood, urine, handwipes prior to and after playing outdoors, and a 6-day duplicate diet. All samples are analyzed for a suite of 20 elements using inductively coupled plasma methods. Results are presented for the first three 6-month sampling periods for lead (Pb) and manganese (Mn). For dustfall accumulation, expressed as metal concentration/m2/30 days, there was no significant difference between homes and daycare centers for either Pb or Mn, no significant change over the three sampling periods (time) for Pb or Mn, and a positive relationship between "traffic exposure" (traffic volume and proximity to the road) and Pb but not Mn. Lead concentrations in soil was a significant predictor for Pb in the house dustfall. For handwipes, the concentrations of Pb and Mn in wipes taken from children after playing outdoors was usually significantly greater than those for wipes taken prior to playing. There was no significant association between the concentrations of either Pb or Mn in handwipes and traffic exposure, and there was no significant association between Pb concentrations in the handwipes and gender, although the latter showed a marginally significant association for Mn (P = 0.053). Age was related to Pb level in the handwipes, with older subjects having higher Pb levels, and there were significant decreases in Pb and Mn concentrations over time. Dustfall accumulation was a significant predictor for Pb in the handwipes, and dust sweepings were a significant predictor of Mn in handwipes. Blood lead (PbB) concentrations ranged from 0.6 to 19 microg/dL (GM 2.6) (n = 269), and manganese in blood (MnB) ranged from 1.8 to 45 microg/L (GM 11.6) (n = 254). There was no significant difference between females and males for either mean PbB or MnB; over time there was a significant decline in PbB but no significant change in MnB. The only significant predictor for PbB was dustfall accumulation, although dietary intake may also be important, and the only significant predictor for MnB was Mn in handwipes prior to playing. At this early stage of the investigation we have not been able to detect any increases in Mn in these environmental samples or blood samples potentially associated with the use of MMT; in fact the Mn levels in handwipes declined over time.

Total parenteral nutrition induced liver pathology: an autopsy series of 24 newborn cases

Total parenteral nutrition (TPN)-induced liver injury is a common complication in neonates managed with newborn intensive care. In several of these cases, irreversible and even fatal liver damage may develop, with patients dying of liver failure. In spite of multiple studies over several years, the pathogenesis of TPN-induced liver damage remains poorly understood. Clinical data from 24 neonates with clinical history of receiving TPN who died at Yale-New Haven Children's Hospital and had autopsies performed, were collected by medical record review without knowledge of liver pathology findings. Liver histological sections from these patients were evaluated for multiple parameters without knowledge of the clinical course. Continuous data were analyzed by Wilcoxon signed-rank test and Mann-Whitney test, and dichotomous data by Fisher's exact test; P < 0.05 was considered significant. Different histopathological abnormalities with varying degrees of severity were observed. A progression in the severity of histopathological changes in relation to duration of TPN administration (DTPN) was found. While patients with DTPN of < 2 wk had no fibrosis or only mild degrees of fibrosis, patients with more than 6 wk of DTPN developed moderate-to-severe fibrosis. Similar results were observed for cholestasis and bile duct proliferation. We did not find significant differences for birth weight, gestational age, occurrence of necrotizing enterocolitis, sepsis, or enteral feedings between the group with normal-to-mild liver changes ( n = 16), and the group with moderate-to-severe liver changes ( n = 8). On the other hand, DTPN was significantly different between these two groups ( P = 0.008). Also, patients small for gestational age ( P = 0.003) and patients with bronchopulmonary dysplasia ( P = 0.001) were more commonly seen in the group with moderate-to-severe histopathological findings. Intracellular copper was detected in 12.5% of patients with moderate-to-severe liver changes, and was found in 50% of patients with normal-to-mild liver findings ( P = 0.04). Detection of copper from tissue sections also decreased with DTPN, being observed in 57% of patients with < 2 wk DTPN and in none of the patients with > 12 wk DTPN. Our findings confirm the known significant relationship between the duration of TPN and liver injury. While previously described associations with birth weight, gestational age, enteral feedings, necrotizing enterocolitis, and sepsis were not noted, our study suggests that poor intrauterine growth may be a significant clinical risk factor for TPN-induced liver injury. In addition, our findings suggest that copper may have a protective effect against the development of TPN-induced liver damage.

Whole-blood manganese levels and brain manganese accumulation in children receiving long-term home parenteral nutrition

Recent reports attribute neurological and cerebral disorders to the accumulation of manganese (Mn) in the brain in patients receiving home parenteral nutrition (HPN). It is desirable to control the amount of Mn delivered to these patients, but a suitable method for monitoring an individual's Mn status and assessing Mn accumulation remains debatable. The aim of this study was to evaluate whether whole-blood manganese levels (WB-Mn) correlate with the accumulation of Mn in the brains of children who receive long-term HPN, using magnetic resonance imaging (MRI) of the brain. Six patients who had received HPN (duration of HPN, 18-137 months) were included in this study. The daily parenteral doses of Mn were calculated while on HPN. WB-Mn was measured and T1-weighted MRI of the brain was obtained for each patient with a 1.5-T MR imager. Twelve months after the withdrawal of Mn from HPN, measurements of WB-Mn and brain MRI were repeated in all patients except for one who was lost after initial examination. The same examinations were performed on an additional patient who had been successfully weaned off a 179 month course of HPN 20 months prior to the initial examination. The parenteral dose of Mn while receiving HPN ranged from 15.7 to 91.5 micro g/kg/day. Initially, MRI showed hyperintensity in the globus pallidus in all patients and in the anterior pituitary in one patient. WB-Mn was elevated in four patients, but was in the normal range in the remaining three. Following subsequent measurements 12 months later, WB-Mn was normal in all patients and MRI hyperintensity remained in the globus pallidus in one patient. One patient was lost after the initial examinations. WB-Mn does not necessarily correlate with the accumulation of Mn in the brain. Periodic MRI should be performed in patients receiving long-term NPN to monitor for excessive Mn accumulation in the brain.

Effect of high dietary manganese intake of neonatal rats on tissue mineral accumulation, striatal dopamine levels, and neurodevelopmental status

Mn is an essential element, but may become neurotoxic at high levels. Recent reports of high Mn levels in hair of children with neurodevelopmental deficits suggest that these deficits could be due to Mn-induced neurotoxic effects on brain dopamine (DA) systems, although the mechanism is not well understood. Infant formulas contain considerably higher concentrations of Mn than human milk. Thus, formula-fed infants are exposed to high levels of Mn at a time when Mn homeostasis is incompletely developed. We studied the effects of dietary Mn supplementation of rat pups on tissue Mn accumulation, brain dopamine levels, infant neurodevelopmental status, and behavior at maturity. Newborn rats were supplemented daily with 0, 50, 250, or 500 microg Mn given orally from day 1 to day 20. Mineral analysis of small intestine and brain at day 14 showed a significant increase of tissue Mn in supplemented rats. Neurodevelopmental tests conducted at various ages showed significant delays as a function of Mn supplementation. At day 32, there was a significant positive relationship between passive avoidance errors and Mn supplementation levels. Brains of animals killed on day 40 showed a significant inverse relationship between Mn supplementation level and striatal dopamine concentration. These observations suggest that dietary exposure to high levels of Mn during infancy can be neurotoxic to rat pups and result in developmental deficits.

Nutrient requirements for preterm infant formulas

Achieving appropriate growth and nutrient accretion of preterm and low birth weight (LBW) infants is often difficult during hospitalization because of metabolic and gastrointestinal immaturity and other complicating medical conditions. Advances in the care of preterm-LBW infants, including improved nutrition, have reduced mortality rates for these infants from 9.6 to 6.2% from 1983 to 1997. The Food and Drug Administration (FDA) has responsibility for ensuring the safety and nutritional quality of infant formulas based on current scientific knowledge. Consequently, under FDA contract, an ad hoc Expert Panel was convened by the Life Sciences Research Office of the American Society for Nutritional Sciences to make recommendations for the nutrient content of formulas for preterm-LBW infants based on current scientific knowledge and expert opinion. Recommendations were developed from different criteria than that used for recommendations for term infant formula. To ensure nutrient adequacy, the Panel considered intrauterine accretion rate, organ development, factorial estimates of requirements, nutrient interactions and supplemental feeding studies. Consideration was also given to long-term developmental outcome. Some recommendations were based on current use in domestic preterm formula. Included were recommendations for nutrients not required in formula for term infants such as lactose and arginine. Recommendations, examples, and sample calculations were based on a 1000 g preterm infant consuming 120 kcal/kg and 150 mL/d of an 810 kcal/L formula. A summary of recommendations for energy and 45 nutrient components of enteral formulas for preterm-LBW infants are presented. Recommendations for five nutrient:nutrient ratios are also presented. In addition, critical areas for future research on the nutritional requirements specific for preterm-LBW infants are identified.

Persistence of mild parkinsonism 4 months after liver transplantation in patients with preoperative minimal hepatic encephalopathy: a study on neuroradiological and blood manganese changes

Pallidal hyperintensity at magnetic resonance imaging (MRI) correlates to blood manganese (Mn) levels and parkinsonian signs in patients with cirrhosis. Similarly, metabolite changes in the basal ganglia (BG) at proton spectroscopy are related to these neurological signs. The evolution of these abnormalities after liver transplantation (OLT) is incompletely described. We evaluated 14 unselected consecutive patients with cirrhosis (minimal hepatic encephalopathy [HE] n=8, no HE n=6) before and 4 months after successful OLT for the evolution of parkinsonism using a validated scale (the United Parkinson's Disease Rating Scale, or UPDRS). Pallidal intensity at MRI, spectroscopic changes in the BG at magnetic resonance spectroscopy (MRS), and whole blood manganese concentrations were measured. After OLT in patients with preoperative minimal HE, the UPDRS scores improved, but mild parkinsonism persisted (16.1+/-3.6 to 6.2+/-4.8, P<0.05). Pallidal hyperintensity remained abnormal in 5/8 of cases, but spectroscopic changes normalized in all patients. Blood Mn remained elevated in 4/6 patients. In patients without HE, UPDRS values remained negligible (2.42+/-1.5 to 2.5+/-1.4). Pallidal hyperintensity normalized in 7/8 patients and spectroscopic changes normalized in all patients. Blood Mn remained elevated in 5/6 patients. Four months after successful OLT, patients with preoperative minimal HE and severe pallidal hyperintensity showed persistent mild parkinsonism. The role of blood manganese determination appears limited in the monitoring of MRI and parkinsonian signs changes after OLT.

Parenteral nutrition-associated liver complications in children

Parenteral nutrition is a life-saving therapy for patients with intestinal failure. It may be associated with transient elevations of liver enzyme concentrations, which return to normal after parenteral nutrition is discontinued. Prolonged parenteral nutrition is associated with complications affecting the hepatobiliary system, such as cholelithiasis, cholestasis, and steatosis. The most common of these is parenteral nutrition-associated cholestasis (PNAC), which may occur in children and may progress to liver failure. The pathophysiology of PNAC is poorly understood, and the etiology is multifactorial. Risk factors include prematurity, long duration of parenteral nutrition, sepsis, lack of bowel motility, and short bowel syndrome. Possible etiologies include excessive caloric administration, parenteral nutrition components, and nutritional deficiencies. Several measures can be undertaken to prevent PNAC, such as avoiding overfeeding, providing a balanced source of energy, weaning parenteral nutrition, starting enteral feeding, and avoiding sepsis.

Organ heavy-metal accumulation during parenteral nutrition is associated with pathologic abnormalities in rats

OBJECTIVES

Metabolic bone disease, hepatic abnormalities, splenic insufficiency, and nephropathy have been associated with long-term total parenteral nutrition (TPN). We determined the heavy-metal contamination in TPN solutions and investigated whether it was associated with organ deposition and pathologic organ damage.

METHODS

Five representative TPN solutions (two adult standard solutions, one renal solution, and one standard pediatric solution to reflect clinical practice) and 28 TPN components were analyzed with inductively coupled plasma mass spectrometry. Twenty-six male Fisher 344 rats were assigned to two groups (chow/NaCl = 8 and TPN = 18). TPN or NaCl was infused at a rate of 50 mL/d. After 14 d, serum, femurs, spine, liver, kidneys, brain, spleen, and testes were analyzed for heavy-metal deposition by using inductively coupled plasma mass spectrometry. Tissues were fixed in formalin, sectioned, and stained with hematoxylin and eosin, periodic acid Schiff, and Masson's trichrome stain. Kidneys were fixed in gluteraldehyde for ultrastructural examination with scanning electron microscopy.

RESULTS

The predominant sources of contaminants in TPN were amino acids (Al, As, Cr, Ge, Pb, Sn), dextrose (As, Ba, Cr, Sn), Ca gluconate (Al), K2PO4 (Al), lipid emulsion (As, Sn), and vitamins (As). Significant variations in the level of contamination depended on TPN formulation and brand of constituents. In the kidney, Pb, Cr, and Mn concentrations were greater than in controls, although there was no correlation with serum creatinine. Hepatic Cr and Pb concentrations were greater in TPN rats, although there was no correlation with serum aspartate aminotransferase or total bilirubin. Splenic Ba, Cr, Ge, Pb, Mn, and Sn concentrations were greater in TPN rats. Only serum Cr concentration was significantly correlated with splenic concentration (r = 0.46, P = 0.04). Brain and serum Ba concentrations were significantly correlated (r = 0.60, P = 0.007). No significant correlations were observed between any other metal in serum and that metal's respective organ concentration. No increase in heavy-metal accumulation was seen in the femur, spine, or testis. There were no significant depositions of As, Cd, Hg, St, or V in any of the organs examined. Serum Al and Cr concentrations were significantly increased in TPN rats, although there was no correlation with tissue concentrations. No significant increases in heavy-metal concentrations in tissue or plasma were observed for any of the other metals measurable by inductively coupled plasma mass spectrometry. Histologically in the TPN group, 50% of the rats had mild to moderate hepatic steatosis and 33% to 50% developed renal morphologic abnormalities; brains and spleens remained histologically normal.

CONCLUSIONS

We found significant heavy-metal contamination of TPN solutions, and this contamination can lead to organ deposition and subsequent histologic abnormalities.

Manganese intoxication during intermittent parenteral nutrition: report of two cases

BACKGROUND AND METHODS

The administration of trace elements is thought to be needed in patients receiving long-term parenteral nutrition. Recently, manganese intoxication or deposition was documented in such patients. We report two cases of manganese intoxication during intermittent parenteral nutrition including manganese. Manganese had been administered for 4 years at a frequency of one or two times per week in one case and for 5 years at a frequency of one or two times per month in the other case. Both cases showed mild symptoms with headache and dizziness. One case had mild hepatic dysfunction and the other did not. The whole-blood manganese level increased in one case, but not in the other case. T1-weighted magnetic resonance images revealed symmetrical high-intensity areas in basal ganglia and thalamus in both cases. After the administration of manganese was stopped, these symptoms all disappeared and the magnetic resonance images abnormalities gradually improved in both patients. Mild long-term manganese intoxication is thus considered to occur regardless of the frequency of using a manganese supplement.

CONCLUSIONS

Patients should be carefully monitored when receiving long-term parenteral nutrition including manganese, even when the manganese dose is small and the frequency of receiving a manganese supplement is low.

Factors associated to hypermanganesemia in patients receiving home parenteral nutrition

BACKGROUND

Home parenteral nutrition (HPN) patients often present hypermanganesamia.

AIM

To examine which factors may be associated to hypermanganesemia in HPN patients.

METHODS

Plasma manganese (Mn), liver function tests, C-reactive protein concentrations, erythrocyte sedimentation rate (ESR), tumor necrosis factor-alpha (TNF- alpha), interleukin-6, soluble receptors of interleukin-2, and blood neopterin concentrations were determined in 21 HPN patients and 10 healthy controls. Brain magnetic resonance imaging (MRI) and careful neurologic clinical examination were performed in 11 patients.

RESULTS

Mn concentration was higher in HPN patients than controls (1.96+/-1.1 vs 0.81+/- 0.4 microg/L;P<0.001) and positively correlated to the amount of parenteral nutrition (PN) supply, transaminases and alkaline phosphatase (r=0.53, P<0.0001) concentrations, as well as to ESR (r=0.61, P<0.0001), TNF- alpha and blood neopterin. The amount of calories provided by PN was positively correlated to inflammatory markers and liver parameters. All patients investigated by MRI showed hyperintense basal ganglia on T1-weighted images suggesting brain Mn deposition. Only one had slight clinical extrapyramidal symptoms.

CONCLUSION

In HPN patients, sustained inflammation may facilitate hypermanganesemia through 1. cholestatic liver disease and thereby decreased Mn biliary excretion, 2. high nutritional requirements (responsible for increased Mn supply), and/or 3. modified Mn metabolism or body distribution. Neurologic complications appeared marginal whereas Mn brain deposition seems frequent.

Safety and efficacy of mangafodipir trisodium (MnDPDP) injection for hepatic MRI in adults: results of the U.S. multicenter phase III clinical trials (safety)

The short-term safety of mangafodipir trisodium (MnDPDP) injection was studied in 546 adults with known or suspected focal liver lesions. An initial contrast-enhanced computed tomography examination was followed by unenhanced magnetic resonance imaging (MRI), injection of MnDPDP (5 micromol/kg), and enhanced MRI. Adverse events were reported for 23% of the patients; most were mild to moderate in intensity, did not require treatment, and were not drug related. The most commonly reported adverse events were nausea (7%) and headache (4%). The incidence of serious adverse events was low (nine events in six patients) and not drug related. Injection-associated discomfort was reported for 69% of the patients, and the most commonly reported discomforts included heat (49%) and flushing (33%). Changes in laboratory values and vital signs were generally transient, were not clinically significant, and did not require treatment. There were no clinically significant short-term risks from exposure to MnDPDP.

Hypermanganesemia in patients receiving total parenteral nutrition

BACKGROUND

Manganese is one of the trace elements that is routinely administered to total parenteral nutrition (TPN) patients. The recommended daily IV dosage ranges from 100 to 800 MICROg. We have used 500 microg daily. Recent reports have suggested neurologic symptoms seen in some patients receiving home parenteral nutrition (HPN) may be due to hypermanganesemia. Therefore, HPN patients and some short-term inpatients receiving TPN were studied to ascertain the relationship between dose and blood levels.

METHODS

Red blood cell manganese levels were obtained by atomic absorptiometry.

RESULTS

The levels in 36 hospitalized, short-term patients obtained within 48 hours of initiating TPN were all normal. The 30 patients receiving TPN from 3 to 30 days had levels that ranged from 4.8 to 28 microg/L (normal, 11 to 23 microg/L). Two patients had abnormal levels, at days 14 and 18. Fifteen of the 21 patients receiving inpatient TPN or HPN for 36 to 5075 days had elevated Mn levels. Only one patient with hypermanganesemia, an inpatient, had abnormal biochemical liver tests (bilirubin and alkaline phosphatase). One of the patients with a high level had some vestibular symptoms attributed to aminoglycoside use and had increased signal density in the globus pallidus on T1-weighted images on magnetic resonance imaging (MRI). A second patient with Mn levels twice normal had no neurologic symptoms, but had similar MRI findings. A third had some basal ganglia symptoms, confirmed by a neurologic evaluation, seizures, and very high Mn levels. The MRI showed no signal enhancement, but motion artifacts limited the study technically.

CONCLUSIONS

Hypermanganesemia is seen in HPN patients receiving 500 microg manganese daily and may have resulted in some neurologic damage in three patients. Hypermanganesemia is sometimes seen after a short course of TPN in inpatients, as early as 14 days. Patients should be monitored for hypermanganesemia if they receive Mn in their TPN for >30 days. A 500 microg/d dose of Mn is probably excessive, and 100 microg/d should probably never be exceeded. Mn should be eliminated from the solution if the Mn level is elevated and should not be readministered unless the level returns to normal or subnormal. Mn should not be supplemented if the patient has liver disease with an elevated bilirubin.

Hypermanganesemia in long-term intravenous nutrition and chronic liver disease

BACKGROUND

Hypermanganesemia and cholestatic liver disease are both recognized complications of long-term IV nutrition. Manganese is primarily excreted in bile, and recent studies have indicated that manganese toxicity may play a role in the pathogenesis of IV nutrition-associated cholestasis.

METHODS

Whole blood and plasma manganese concentrations were measured in patients receiving long-term home IV nutrition (HIN, n = 30). Whole blood manganese concentrations also were measured in patients with chronic liver disease (CLD, n = 10) and control subjects (n = 10).

RESULTS

Whole blood manganese concentrations of all CLD patients were within the reference interval (73 to 210 nmol/L) and were not different from those of the control group (151 +/- 44 nmol/L, CLD vs 155 +/- 35 nmol/L, control; not significant), despite the presence of cholestasis. In contrast, whole blood manganese concentration was increased (>210 nmol/L) in 26 patients, and plasma manganese concentration increased (>23 nmol/L) in 23 of the patients receiving HIN. None of the patients exhibited neurologic signs of manganese toxicity. There was no correlation between whole blood manganese concentrations and markers of cholestasis, IV manganese intake, or duration of HIN. However, plasma manganese concentration correlated both with average weekly IV manganese intake (r = .44, p = .02) and with gamma-glutamyl transferase (r = .43, p = .02) and alkaline phosphatase activities (r = .55, p = .003).

CONCLUSIONS

Cholestatic liver disease does not appear to contribute to increased whole blood manganese concentrations in patients not receiving HIN. Plasma manganese concentrations in patients receiving HIN reflect recent manganese exposure and impaired excretion where cholestasis is present. The lack of relationship between plasma and whole blood manganese concentrations suggests that factors other than manganese intake and excretion affect intracellular concentrations.

Technical aspects of trace element supplementation

Routine supplementation of total parenteral nutrition mixtures with the readily available single or combination trace elements products is becoming more widespread. As more is learned about deficiency syndromes and monitoring techniques, so too must we understand more about the physicochemical interactions between individual trace elements and other nutrients, that could ultimately affect bioavailability. Expert pharmaceutical assessment of these complex reactions, that have been demonstrated to occur in solution, becomes increasingly important in order to optimize the efficacy of micronutrient therapy.

Existing and emerging mechanisms for transport of iron and manganese to the brain

The metals iron (Fe) and manganese (Mn) are essential for normal functioning of the brain. This review focuses on recent developments in the literature pertaining to Fe and Mn transport. These metals are treated together because they appear to share several transport mechanisms. In addition, several neurological diseases such as Alzheimer's Disease, Parkinson's Disease, and Huntington's Disease are all associated with Fe mismanagement in the brain, particularly in the striatum and basal ganglia. Similarly, Mn accumulation in brain also appears to target the same brain regions. Therefore, stringent regulation of the concentration of these metals in the brain is essential. The homeostatic mechanisms for these metals must be understood in order to design neurotoxicity prevention strategies.

Tremor and seizures associated with chronic manganese intoxication

Tremor and seizures developed in a 2-year-old girl receiving total parenteral nutrition. T1-weighted images on MRI revealed areas of hyperintensity in the basal ganglia, brainstem and cerebellum. Blood manganese was elevated. The symptoms and MRI abnormalities disappeared after withdrawal of manganese administration. The recommendation of daily parenteral manganese intake was discussed.

Manganese deficiency and toxicity: are high or low dietary amounts of manganese cause for concern?

Manganese is an essential trace element that is required for the activity of several enzymes. Manganese is also quite toxic when ingested in large amounts, such as the inhalation of Mn-laden dust by miners. This review examines Mn intake by way of the food supply and poses the question: Is there reason to be concerned with Mn toxicity or deficiency in free-living populations in North America? Although much remains to be learned of the functions of Mn, at present there are only a few vaguely described cases of Mn deficiency in the medical literature. Given the heterogeneity of the North American food supply, it is difficult to see the possibility of more than greatly isolated and unique instances of Mn deficiency. However, low Mn-dependent superoxide dismutase activity may be associated with cancer susceptibility, and deserves further study. There may be reasons, however, to be concerned about Mn toxicity under some very specialized conditions. Increasing numbers of young people are adopting a vegetarian lifestyle which may greatly increase Mn intake. Iron deficiency may increase Mn absorption and further increase the body-burden of Mn, especially in vegetarians. Mn is eliminated primarily through the bile, and hepatic dysfunction could depress Mn excretion and further contribute to the body burden. Would such a combination of events predispose substantial numbers of people to chronic Mn toxicity? At present, there is no definite proof of this occurring, but given the state of knowledge at the present time, more studies with longer time-frames and more sensitive methods of analysis are needed.

Trace element deficiency and toxicity

Trace elements are involved in enzymatic activities, immunological reactions, physiological mechanisms and carcinogenesis. Deficiency in some trace elements, such as iron and iodine, is still an important health problem, especially in developing countries. Some groups of individuals are more likely to develop trace element deficiency. The role of trace elements deficiency is suspected in various clinical situations and is now confirmed by well designed supplementation studies. Although toxicity of trace elements with clinical manifestations is rare, it has been observed that manganese toxicity may occur in patients receiving parenteral nutrition. Recent data about trace elements deficiency and toxicity are indicated in this review.

Monitoring and complications of parenteral nutrition

A knowledge of the complications of parenteral nutrition is inherent in the design of any monitoring system. In the initial stages of therapy, the complications are usually of electrolyte imbalance. It must also be appreciated that the provision of nutrition to severely malnourished patients will expose underlying deficiencies, particularly of phosphates and trace elements. In long-term parenteral nutrition, the complications can be broadly divided into those associated with the line and metabolic complications. The line complications include: line blockage, sepsis, and pulmonary embolism. The most important metabolic complication is undoubtedly liver cholestasis, which may be associated with recurrent episodes of sepsis. Any department undertaking long-term parenteral nutrition should have an active nutrition team to avoid complications and audit outcome.

Long-term outcome of brain manganese deposition in patients on home parenteral nutrition

Manganese intoxication has been described in children on long term parenteral nutrition presenting with liver and nervous system disorders. Cases are reported of a brother and sister on long term parenteral nutrition with hypermanganesaemia and basal ganglia manganese deposition, detected by magnetic resonance imaging (MRI), without overt neurological signs. Following reduction of manganese intake, basal ganglia manganese was monitored by repeated MRI, and neurological and developmental examinations. An MRI intensity index of the globus pallidus declined over a three year period from 0.318 and 0.385 to 0.205 and 0.134 with concomitant falls in whole blood manganese from 323 and 516 to 226 and 209 nmol/l (normal range, 73-210 nmol/l). Unlike adult experience these children developed normally without neurological signs. In conclusion, deposited manganese is removed from neural tissue over time and the prognosis is good when neurological manifestations and liver disease are absent.

Effect of biliary ligation on manganese accumulation in rat brain

Neurologic and radiologic disorders have been reported to occur in miners inhaling manganese (Mn)-laden dust and in humans receiving long-term parenteral nutrition. These abnormalities have been attributed to Mn intoxication because of elevated serum Mn concentrations. Because the liver, by way of the bile, is the major route of Mn excretion, it is possible that anything that decreases biliary excretion could increase accumulation of Mn in the brain. The purpose of this study was to determine whether biliary ligation would increase Mn accumulation in the brain of rats that were exposed to deficient or adequate amounts of dietary manganese. The first experiment had a 2 x 3 factorial design, two levels of Mn (0 or 45 microg/g diet) and three surgical treatments (control, sham, or bile-ligation). Animals were sacrificed 10 d after being fed 54Mn. In experiment 2, animals that had a sham operation or bile-ligation were sacrificed at 8 time points after being injected intraportally with 54Mn complexed to albumin. The biliary-ligated animals had a significantly (p < 0.001) smaller percentage of the 54Mn in their brains (when expressed as a percentage of whole animal 54Mn) than the sham-operated animals. Mn deficiency had a similar effect. However, we did observe an increased accumulation of the radioisotope in the brain over time. Therefore, in short-term studies, biliary-ligated rats do not appear to be a good model for Mn accumulation in the brains of people with cholestatic liver disease.

Liver complications of pediatric parenteral nutrition--epidemiology

Total parenteral nutrition (TPN)-induced liver disease develops in 40-60% of infants who require long-term TPN for intestinal failure. The clinical spectrum includes cholestasis, cholelithiasis, hepatic fibrosis with progression to biliary cirrhosis, and the development of portal hypertension and liver failure in a significant number of children who are totally parenterally fed. The pathogenesis is multifactorial and is related to prematurity, low birth weight, and duration of TPN. The degree and severity of the liver disease is related to recurrent sepsis including catheter sepsis, bacterial translocation, and cholangitis. Lack of enteral feeding leading to reduced gut hormone secretion, reduction of bile flow, and biliary stasis may be important mechanisms in the development of cholestasis, biliary sludge, and cholelithiasis. Although it is unlikely that modern TPN solutions have a major role in the etiology of TPN liver disease, manganese toxicity recently has been recognized in children with hepatic dysfunction on TPN. Although there is a definite relationship with the degree of manganese toxicity and hepatic decompensation, it is not yet clear whether this is a primary mechanism or whether the high levels are related to reduced biliary excretion of manganese. The management strategies for the prevention of TPN-induced liver disease include early enteral feeding, a multidisciplinary approach to the management of parenteral nutrition, and aseptic catheter techniques to reduce sepsis. The administration of ursodeoxycholic acid may improve bile flow and reduce gall bladder and intestinal stasis. As survival from isolated intestinal transplantation improves, this therapeutic option should be considered before TPN liver disease becomes irreversible and combined liver and small bowel transplantation is required.

Micronutrients and outcome

Micronutrient deficiency not only causes symptoms of severe deficiency, but may also cause more subtle effects on tissue function, including immune deficiency and oxidative damage. The duration of a deficiency state, which is necessary before such effects are clinically significant, is not known. Most biochemical tests are relatively insensitive in detecting changes in micronutrient status, although they do provide a crude index. Many tests are nonspecific, being affected by the acute phase response as well as by nutritional status. Cellular tests are more sensitive and specific than tests in plasma. When interpreted carefully in association with the knowledge of the patient's clinical condition and nutritional intake, laboratory tests can be helpful in diagnosing deficiency states or conditions of excess provision, and in monitoring progress. Well conducted clinical trials of micronutrients in nutritional support are beginning to appear in the literature. Further studies are urgently required that relate outcome to levels of provision and biochemical indices of nutrient status.

Manganese toxicity in children receiving long-term parenteral nutrition

BACKGROUND

In patients receiving long-term parenteral nutrition (PN), cholestatic disease and nervous system disorders have been associated with high blood concentrations of manganese. In such patients, the normal homoeostatic mechanisms of the liver and gut are bypassed and the requirement for this trace element is not known; nor has it been certain whether hypermanganesaemia causes the cholestasis or vice versa. We explored the direction of effect by serial tests of liver function after withdrawal of manganese supplements from children receiving long-term PN. We also examined the relation between blood manganese concentrations and brain lesions, as indicated by clinical examination and magnetic resonance imaging (MRI).

METHODS

From a combined group of 57 children receiving PN we identified 11 with the combination of hypermanganesaemia and cholestasis; one also had a movement disorder. Manganese supplements were reduced in the first three and withdrawn in the remainder. MRI was done in two of these children. We also looked at manganese concentrations and MRI scans in six children who had received PN for more than 2 years without developing liver disease.

FINDINGS

In the hypermanganesaemia/cholestasis group, four of the 11 patients died. In the seven survivors baseline whole-blood manganese was 615-1840 nmol/L, and after 4 months it had declined by a median of 643 nmol/L (p < 0.01). Over the same interval total bilirubin declined by a median of 70 mumol/L (p < 0.05). Two of these children had movement disorders, one of whom survived to have an MRI scan; this showed, with T1 weighted images, bilateral symmetrically increased signal intensity in the globus pallidus and subthalamic nuclei. Such changes were also seen in five other children--one from the hypermanganesaemia/cholestasis group and four of six in the long-term PN group without liver disease (in all of whom blood manganese was above normal).

INTERPRETATION

The cholestasis complicating PN is multifactorial, but these results add to the evidence that manganese contributes. In view of the additional hazard of basal ganglia damage from high manganese levels in children receiving long-term PN, we recommend a low dose regimen of not more than 0.018 mumol/kg per 24 h together with regular examination of the nervous system.

Parenteral nutrition-related cholestasis in postsurgical neonates: multivariate analysis of risk factors

The medical records of 74 neonates dependent on parenteral nutrition for at least 21 days after emergency abdominal surgery (performed between 1988 and 1992) were reviewed respectively. The role of enteral starvation, prematurity, composition and duration of parenteral nutrition, and sepsis in the evolution of parenteral nutrition-related cholestasis was evaluated by multiple regression analysis. The most important factors for cholestasis were low gestational age (median, 34 weeks), early exposure to parenteral nutrition, and sepsis. Episodes of sepsis were associated with a 30% increase in the bilirubin level. Enteral starvation and composition and the duration of parenteral nutrition solutions did not correlate significantly with the development of cholestasis. Prevention of sepsis should be the priority in minimising cholestasis in postsurgical neonates who are dependent on parenteral nutrition.

Fatal acute hepatorenal failure following potassium permanganate ingestion

Potassium permanganate (KMnO4), a powerful oxidizing agent, is readily available without prescription. Tissue contact produces coagulation necrosis and the lethal consequences of oral ingestion are well described, with most deaths because of airway oedema and obstruction or circulatory collapse. Whilst systemic toxicity is reported, its mechanism is unclear. We describe a case of suicidal ingestion of KMnO4 followed by acute hepatorenal toxicity resulting in the death of the patient. The clinical course bore close resemblance to that of severe paracetamol overdose. We discuss the pathogenesis of the systemic toxicity of KMnO4 and postulate that it is due to oxidative injury from free radicals generated by the absorbed permanganate ion. We recommend that N-acetyl cysteine be given within the first few hours to all patients with potassium permanganate poisoning.