Alpha-1-acid glycoprotein and its potential impact on local anesthetic dose in neonates.

BACKGROUND: Alpha-1-acid glycoprotein is an acute-phase protein with a high affinity for amide local anesthetics. Compared to adults, neonates have lower concentrations of this glycoprotein in plasma, and are therefore at higher risk of developing local anesthetic toxicity. Alpha-1-acid glycoprotein concentrations rise in adults after surgery as a response to stress as well as in inflammatory conditions. Previous studies have shown that concentrations of alpha-1-acid-glycoprotein in neonates vary postpartum, influenced by gestational age and mode of delivery. AIM: This study aims to determine the concentrations of alpha-1-acid glycoprotein pre- and postoperatively in neonates undergoing major surgery. This information is important for determining safe and effective dosage of local anesthetic in this vulnerable group of patients. METHODS: In this prospective observational study, 25 neonates (median 3 days of age) undergoing major surgery were included. Blood sampling was performed preoperatively and at four occasions postoperatively. Alpha-1-acid-glycoprotein plasma concentrations were analyzed using an immunoturbidimetric assay. Mann-Whitney U test, Kruskal-Wallis and Spearman ranking correlation test were used for the statistical analysis. RESULTS: Higher plasma concentrations of alpha-1-acid-glycoprotein were found 48 h postoperatively compared to preoperatively [median (inter-quartile range) 0.815 g L-1 (0.663-0.983 g L-1 ) vs. 0.300 g L-1 (0.205-0.480 g L-1 p < 0.001)], respectively. It was not possible to detect any influence of sex, postnatal age, gestational age, or delivery mode on alpha-1-acid-glycoprotein concentrations in our data. CONCLUSIONS: Alpha-1-acid-glycoprotein concentrations increase in neonates as a response to surgery regardless of gestational age, sex, or mode of delivery.

Using a low-molecular weight heparin-calibrated anti-factor Xa assay to assess the concentration of apixaban and rivaroxaban.

INTRODUCTION: Direct oral anticoagulant (DOAC)-inhibiting factor Xa (FXa-DOAC) are being increasingly used as prophylaxis of venous thromboembolism and for prevention of stroke in patients with atrial fibrillation. In contrast to vitamin K antagonists, DOACs do not require monitoring in general. However, it is sometimes of value in the acute setting, for instance when considering a reversal agent in uncontrolled bleeding in patients on DOAC. METHODS: We evaluated if a low-molecular weight heparin (LMWH)-calibrated anti-factor Xa assay could be used to estimate FXa-DOAC concentration in the concentration range <100 ng/mL by spiking known concentrations of FXa-DOAC and from those result calculate the FXa-DOAC concentration from the response of the LMWH assay. This procedure was then evaluated by comparing the result with a drug-calibrated chromogenic assay and liquid chromatography tandem mass spectrometry (LC-MS/MS) on clinical plasma samples from patients treated with apixaban or rivaroxaban. RESULTS: Although the measuring range was narrower for the LMWH-calibrated assay, concentrations recalculated from the LMWH assay was comparable with those measured by the drug-calibrated method when compared with LC-MS/MS. CONCLUSION: We suggest that an LMWH-calibrated anti-factor Xa assay can be used after characterization of the response of FXa-DOACs to give guidance on the concentration of apixaban and rivaroxaban. Shorter turnaround time than LC-MS/MS and the greater availability than drug-calibrated chromogenic assays could make this a valuable option in the acute setting.

Influence of Blood-Brain Barrier Integrity on Brain Protein Biomarker Clearance in Severe Traumatic Brain Injury: A Longitudinal Prospective Study.

Brain protein biomarker clearance to blood in traumatic brain injury (TBI) is not fully understood. The aim of this study was to analyze the effect that a disrupted blood-brain barrier (BBB) had on biomarker clearance. Seventeen severe TBI patients admitted to Karolinska University Hospital were prospectively included. Cerebrospinal fluid (CSF) and blood concentrations of S100 calcium binding protein B (S100B) and neuron-specific enolase (NSE) were analyzed every 6-12 h for ∼1 week. Blood and CSF albumin were analyzed every 12-24 h, and BBB integrity was assessed using the CSF:blood albumin quotient (QA). We found that time-dependent changes in the CSF and blood levels of the two biomarkers were similar, but that the correlation between the biomarkers and QA was lower for NSE (ρ = 0.444) than for S100B (ρ = 0.668). Because data were longitudinal, we also conducted cross correlation analyses, which indicated a directional flow and lag-time of biomarkers from CSF to blood. For S100B, this lag-time could be ascribed to BBB integrity, whereas for NSE it could not. Upon inferential modelling, using generalized least square estimation (S100B) or linear mixed models (NSE), QA (p = 0.045), time from trauma (p < 0.001), time from trauma2 (p = 0.023), and CSF biomarker levels (p = 0.008) were independent predictors of S100B in blood. In contrast, for NSE, only time from trauma was significant (p < 0.001). These findings are novel and important, but must be carefully interpreted because of different characteristics between the two proteins. Nonetheless, we present the first data that indicate that S100B and NSE are cleared differently from the central nervous system, and that both the disrupted BBB and additional alternative pathways, such as the recently described glymphatic system, may play a role. This is of importance both for clinicians aiming to utilize these biomarkers and for the pathophysiological understanding of brain protein clearance, but warrants further examination.

Zinc deficiency in patients with chronic pancreatitis.

BACKGROUND: Zinc is a key element in numerous proteins and plays an important role in essential cell functions such as defense against free radicals and DNA damage repair. Chronic pancreatitis (CP) is a chronic inflammation with progressive fibrosis of pancreas ultimately resulting in pancreatic exocrine insufficiency (PEI), which is associated with malnutrition. Studies analyzing zinc levels in patients with CP are sparse and lead to conflicting results. AIM: To investigate serum zinc levels in patients with CP of various etiologies. METHODS: Between October 2015 and March 2018, patients with a diagnosis of CP were identified and recruited from the Pancreatic Outpatient Clinic at the Karolinska University Hospital in Stockholm, Sweden. Demographic, clinical and laboratory data were analyzed. Etiology of CP was determined according to the M-ANNHEIM classification system into the following etiological subcategories: alcohol consumption, nicotine consumption, hereditary factors, efferent pancreatic duct factors and immunological factors. Pancreatic exocrine function was defined as normal (fecal elastase 1 > 200 µg/g), mildly reduced (100-200 µg/g) and severely reduced (fecal elastase 1 < 100 µg/g). RESULTS: A total of 150 patients were included in the analysis. Zinc deficiency (< 11 µmol/L) was present in 39 (26.0%) of patients: 22 females and 17 males. In the group of patients with zinc deficiency, 76.7% of patients had an exocrine pancreatic insufficiency (FE-1 < 200 µg/g). Older age was significantly associated with low zinc levels. Following a univariate analysis, patients aged 60-69 and patients ≥ 70 years of age had a significantly higher prevalence of zinc deficiencies compared to patients < 40 years of age [OR: 3.8, 95%CI (1.08-13.4); P = 0.04]; [OR 6.26, 95%CI (1.94-20.2), P > 0.002]. Smoking and number of pack-years were additionally associated with low zinc levels. The risk of zinc deficiency in current smokers and smokers with ≥ 20 pack-years was approximately three times higher compared to those who had never smoked. Gender, body mass index, etiology of CP, presence of diabetes mellitus, levels of glycated hemoglobin (HbA1c), bone mineral density, alcohol intake and presence of PEI were not associated with low zinc levels. CONCLUSION: Zinc deficiency is common in patients with CP and is significantly associated with age ≥ 60, smoking and the number of pack-years, but not with PEI.

Altered expression of low affinity insulin-like growth factor binding protein related proteins in hepatoblastoma.

Hepatoblastoma is a poorly understood rare pediatric liver tumour. We have previously shown that the IGF-axis is seriously disrupted in this tumour type. With the recent discovery that several other proteins also have the potential to bind to IGFs called insulin-like growth factor binding protein related proteins (IGFBP-rPs), we undertook an examination of several such genes in a series of hepatoblastomas with matched normal liver tissue. The expression profiles obtained reveal that the expression of these genes are also disturbed in these tumours, and may have implications for our understanding of the IGF-axis and its importance in this disease.