Vitamin B6 deficiency with normal plasma levels of pyridoxal 5'-phosphate in perinatal hypophosphatasia.

Pyridoxal 5'-phosphate (PLP), the principal circulating form of vitamin B6 (B6), is elevated in the plasma of individuals with hypophosphatasia (HPP). HPP is the inborn-error-of-metabolism caused by loss-of-function mutation(s) of ALPL, the gene that encodes the "tissue-nonspecific" isoenzyme of alkaline phosphatase (TNSALP). PLP accumulates extracellularly in HPP because it is a natural substrate of this cell-surface phosphomonoester phosphohydrolase. Even individuals mildly affected by HPP manifest this biochemical hallmark, which is used for diagnosis. Herein, an exclusively breast-fed newborn boy with life-threatening perinatal HPP had uniquely normal instead of markedly elevated plasma PLP levels before beginning asfotase alfa (AA) TNSALP-replacement therapy. These abnormal PLP levels were explained by B6 deficiency, confirmed by his low plasma level of 4-pyridoxic acid (PA), the B6 degradation product. His mother, a presumed carrier of one of his two ALPL missense mutations, had serum ALP activity of 50 U/L (Nl 40-130) while her plasma PLP level was 9 µg/L (Nl 5-50) and PA was 3 µg/L (Nl 3-30). Her dietary history and breast milk pyridoxal (PL) level indicated she too was B6 deficient. With B6 supplementation using a breast milk fortifier, the patient's plasma PA level corrected, while his PLP level remained in the normal range but now in keeping with AA treatment. Our experience reveals that elevated levels of PLP in the circulation in HPP require some degree of B6 sufficiency, and that anticipated increases in HPP can be negated by hypovitaminosis B6.

Intravenous Lipid Emulsions in Infants: Is Balanced Better?

Parenteral nutrition (PN) is frequently required by extremely preterm infants due to gastrointestinal immaturity and complications of prematurity. Parenteral nutrition-associated cholestasis (PNAC) and intestinal failure-associated liver disease (IFALD) are common complications of prolonged PN. Plant-based intravenous lipid emulsions, containing proinflammatory omega-6 fatty acids and phytosterols, may contribute to these conditions as well as other comorbidities such as bronchopulmonary dysplasia and retinopathy of prematurity. Intravenous lipid emulsions containing animal-based fats, such as fish oil, contain fewer proinflammatory omega-6 fatty acids and more anti-inflammatory omega-3 fatty acids and antioxidants. SMOFlipid, recently Food and Drug Administration (FDA)-approved for adult use, is a blend of plant- and animal-based lipid emulsions with a favorable omega-6:omega-3 ratio that may prevent the development and progression of PNAC/IFALD in infants. Careful review of data supporting this alternative intravenous lipid emulsion is required prior to widespread use in neonatal intensive care.

AMP kinase promotes glioblastoma bioenergetics and tumour growth.

Stress is integral to tumour evolution, and cancer cell survival depends on stress management. We found that cancer-associated stress chronically activates the bioenergetic sensor AMP kinase (AMPK) and, to survive, tumour cells hijack an AMPK-regulated stress response pathway conserved in normal cells. Analysis of The Cancer Genome Atlas data revealed that AMPK isoforms are highly expressed in the lethal human cancer glioblastoma (GBM). We show that AMPK inhibition reduces viability of patient-derived GBM stem cells (GSCs) and tumours. In stressed (exercised) skeletal muscle, AMPK is activated to cooperate with CREB1 (cAMP response element binding protein-1) and promote glucose metabolism. We demonstrate that oncogenic stress chronically activates AMPK in GSCs that coopt the AMPK-CREB1 pathway to coordinate tumour bioenergetics through the transcription factors HIF1α and GABPA. Finally, we show that adult mice tolerate systemic deletion of AMPK, supporting the use of AMPK pharmacological inhibitors in the treatment of GBM.

Perinatal and neonatal use of sedation and analgesia.

Optimal obstetric and neonatal care requires the provision of adequate analgesia for painful procedures. However, anesthetic and analgesic agents have the potential to adversely impact the developing fetal/neonatal brain. In this setting, clinicians must assess the risks and benefits of pharmacologic anesthesia and analgesia for specific indications in this population. General anesthesia is required for non-obstetric surgery and cesarean section in the absence of neuraxial anesthesia for the health of the mother and fetus. Although experimental data raise concerns, human data are reassuring and future research may focus on neuroprotective adjuncts in the setting of repeated or prolonged anesthetic exposures. Opioid analgesia is standard of care for preterm infants undergoing major procedures including invasive surgery and endotracheal intubation. The use of opioids for agitation resulting from mechanical ventilation is controversial, but prevalent. Randomized and retrospective studies detect short-term toxicity with inconclusive long-term impact, suggesting the need to explore alternative therapies.

Treatment of Citrobacter koseri infection with ciprofloxacin and cefotaxime in a preterm infant.

OBJECTIVE: To report a case of successful treatment of Citrobacter koseri infection in a preterm infant as a means of challenging the current treatment recommendations on the basis of pharmacodynamic and pharmacokinetic considerations. CASE SUMMARY: A premature infant was diagnosed with C. koseri sepsis after 3 weeks in intensive care. Concern for meningitis was based on the propensity for central nervous system (CNS) involvement with Citrobacter infection along with new findings of ventriculomegaly and hydrocephalus shown on cranial ultrasound (CUS). The infant was treated with ciprofloxacin 10-20 mg/day and cefotaxime 100 mg/day for 21 days. After treatment, lumbar puncture was normal, follow-up CUS returned to baseline, and the infant passed a hearing screen after discharge. A favorable outcome was achieved in this case. DISCUSSION: Approximately 76% of neonatal patients infected with C. koseri develop brain abscesses. The mortality rate for meningitis due to Citrobacter spp. is approximately 30%, and of the infants who survive, more than 80% have some degree of mental retardation. Third-generation cephalosporins and aminoglycosides are traditional therapies against this infection. The current antibiotic strategies have failed to prevent the high rates of morbidity and mortality associated with Citrobacter infections. A possible basis for these poor outcomes is failure to apply appropriate pharmacokinetic and pharmacodynamic principles in selecting antibiotics that will achieve adequate concentrations to kill the bacteria in granulocytes within the CNS. Based on favorable sensitivity data, penetration into neutrophils and the CNS, and favorable toxicity profiles, ciprofloxacin and meropenem would appear to be the most appropriate antibiotic treatment options for systemic infection or meningitis caused by C. koseri. CONCLUSIONS: Ciprofloxacin and meropenem should be considered antibiotic treatment options for systemic infection or meningitis caused by C. koseri.

The role of an intravenous fat emulsion composed of fish oil in a parenteral nutrition-dependent patient with hypertriglyceridemia.

Hypertriglyceridemia is a common complication in patients receiving parenteral nutrition (PN). Management typically involves withholding the IV fat emulsion (IVFE) until serum triglyceride levels normalize. In some instances, this practice may predispose patients to the development of essential fatty acid deficiency (EFAD) unless alternative therapies such as oral or topical oils are used. This is especially true in patients unable to tolerate enteral intake. We describe the management of hypertriglyceridemia in a 12-year-old boy dependent on PN who developed EFAD due to prolonged use of fat-free PN. His course was further complicated by PN-associated liver disease. Treatment involved the use of an IVFE derived from fish oils. Within 3 weeks, there was clinical improvement in EFAD and hypertriglyceridemia. The patient's triene:tetraene ratio decreased from 0.207 to 0.044 (normal: 0.013-0.05). Similarly, his serum triglyceride levels decreased from 628 mg/dL to 183 mg/dL (normal: <200 mg/dL). After 2 months of treatment, he was successfully transitioned to enteral feedings; hepatic function normalized, as did the essential fatty acid profile and serum triglycerides levels. This suggests that using fish-oil-based IVFE may be an effective alternative to conventional IVFE in PN-dependent patients whose clinical course is complicated by hypertriglyceridemia.