Intrauterine inflammation, insufficient to induce parturition, still evokes fetal and neonatal brain injury

Exposure to prenatal inflammation is a known risk factor for long term neurobehavioral disorders including cerebral palsy, schizophrenia, and autism. Models of systemic inflammation during pregnancy have demonstrated an association with an immune response an adverse neurobehavioral outcomes for the exposed fetus. Yet, the most common route for an inflammatory exposure to a fetus is from intrauterine inflammation as occurs with chorioamnionitis. The aims of this study were to assess the effect of intrauterine inflammation on fetal and neonatal brain development and to determine if the gestational age of exposure altered the maternal or fetal response to inflammation.CD-1 timed pregnant mice on embryonic day 15 (E15) and E18.5 were utilized for this study. Dams were randomized to receive intrauterine infusion of lipopolysaccharide (LPS, 50 μg/dam) or normal saline. Different experimental groups were used to assess both acute and long-term outcomes. For each gestational age and each treatment group, fetal brains, amniotic fluid, maternal serum and placentas were collected 6 h after intrauterine infusion. Rates of preterm birth, maternal morbidity and litter size were assessed. IL6 levels were assayed in maternal serum and amniotic fluid.An immune response was determined in the fetal brains and placentas by QPCR. Cortical cultures were performed to assess for fetal neuronal injury. Gene expression changes in postnatal day 7 brains from exposed and unexposed pups were determined.In the preterm period, low dose LPS resulted in a 30% preterm birth rate. Litter sizes were not different between the groups at either gestational age. IL6 levels were not significantly increased in maternal serum at either gestational time period. Low dose LPS increased IL6 levels in the amniotic fluid from exposed dams in the term but not preterm period. Regardless of gestational age of exposure, low dose intrauterine LPS activated an immune response in the placenta and fetal brain. Exposure to intrauterine LPS significantly decreased dendritic counts in cortical cultures from both the preterm and term period. Exposure to intrauterine inflammation altered gene expression patterns in the postnatal brain; this effect was dependent on gestational age of exposure.In conclusion, intrauterine inflammation, even in the absence of preterm parturition, can evoke fetal brain injury as evidence by alterations in cytokine expression and neuronal injury. Despite an absent or limited maternal immune response in low dose intrauterine inflammation, the immune system in the placenta is activated which is likely sufficient to induce a fetal immune response and subsequent brain injury. Changes in the fetal brain lead to changes in gene expression patterns into the neonatal period. Subclinical intrauterine inflammation can lead to fetal brain injury and is likely to be mechanistically associated with long term adverse outcomes for exposed offspring.     

The association of diabetes and dementia and possible implications for nondiabetic populations

Diabetes and prediabetic states have consistently been shown to be risk factors for cognitive decline, mild cognitive impairment and dementia. The importance of these findings is that diabetes and diabetes-related factors are modifiable, potentially permitting interventions aimed at postponing or preventing dementia. However, diabetes control cannot yet be implemented universally in diabetic subjects as a strategy for dementia prevention since the mechanisms by which diabetes impairs brain function and cognition are not fully understood. It is not clear which of the diabetes-related factors is crucial to this relationship. In addition, strict diabetic control has been demonstrated to carry risk for certain diabetic populations. The aim of the current article is to discuss current understanding of the relationships of diabetes and some of its characteristics with dementia, and suggest future questions to be answered.     

Intracranial Pressure and Experimental Model of Diffuse Brain Injury in Rats

Objective

In this study, we present a simple closed head injury model as a two-stage experiment. The height of the weight drop enables gradation of head trauma severity.

Methods

The head injury device consists of three parts and there are three adjustable parameters-weight (100-600 g), height of fall (5-100 cm) and elasticity of the springs. Thirty male Wistar rats underwent monitoring of intracranial pressure with and without induction of the head injury.

Results

The weight drop from 45 to 100 cm led to immediate seizure activity and early death of the experimental animals. Severe head injury was induced from 40 cm weight drop. There was 50% mortality and all surviving rats had behavioral deterioration. Intracranial pressure was 9.3 ± 3.76 mmHg. Moderate head injury was induced from 35 cm, mortality decreased to 20-40%, only half of the animals showed behavioral pathology and intracranial pressure was 7.6 ± 3.54 mmHg. Weight drop from 30 cm caused mild head injury without mortality and neurological deterioration. Intracranial pressure was slightly higher compared to sham group- 5.5 ± 0.74 mmHg and 2.9 ± 0.81 mmHg respectively.

Conclusion

This model is an eligible tool to create graded brain injury with stepwise intracranial pressure elevation.     

High Potassium Intake Enhances the Inhibitory Effect of 11,12-EET on ENaC

High dietary potassium stimulates the renal expression of cytochrome P450 (CYP) epoxygenase 2C23, which metabolizes arachidonic acid (AA). Because the AA metabolite 11,12-epoxyeicosatrienoic acid (11,12-EET) can inhibit the epithelial sodium channel (ENaC) in the cortical collecting duct, we tested whether dietary potassium modulates ENaC function. High dietary potassium increased 11,12-EET in the isolated cortical collecting duct, an effect mimicked by inhibiting the angiotensin II type I receptor with valsartan. In patch-clamp experiments, a high potassium intake or treatment with valsartan enhanced AA-induced inhibition of ENaC, an effect mediated by a CYP-epoxygenase–dependent pathway. Moreover, high dietary potassium and valsartan each augmented the inhibitory effect of 11,12-EET on ENaC. Liquid chromatography/mass spectrometry showed that the rate of EET conversion to dihydroxyeicosatrienoic acids (DHET) was lower in renal tissue obtained from rats on a high-potassium diet than from those on a control diet, but this was not a result of altered expression of soluble epoxide hydrolase (sEH). Instead, suppression of sEH activity seemed to be responsible for the 11,12-EET–mediated enhanced inhibition of ENaC in animals on a high-potassium diet. Patch-clamp experiments demonstrated that 11,12-DHET was a weak inhibitor of ENaC compared with 11,12-EET, whereas 8,9- and 14,15-DHET were not. Furthermore, inhibition of sEH enhanced the 11,12-EET–induced inhibition of ENaC similar to high dietary potassium. In conclusion, high dietary potassium enhances the inhibitory effect of AA and 11,12-EET on ENaC by increasing CYP epoxygenase activity and decreasing sEH activity, respectively.We previously demonstrated that cytochrome P450 (CYP) epoxygenase-dependent arachidonic acid (AA) metabolism inhibited epithelial sodium channel (ENaC) in the cortical collecting duct (CCD) and that 11,12-epoxyeicosatrienoic acid (11,12-EET) was responsible for mediating the effect of AA on ENaC.¹ Furthermore, the observation that AA failed to inhibit ENaC in the CCD of the mice with a low expression of CYP2C44 suggests that CYP2C44 and its orthologs may be responsible for mediating the inhibitory effect of AA.² The expression of CYP2C44 or its orthologs has been shown to be regulated by dietary Na intake: A high Na intake stimulates² whereas a low, Na intake suppresses the expression of CYP2C44 homologue.³ A large body of evidence has suggested that EET plays a role in the regulation of renal Na transport and salt-sensitive hypertension.^1,2,4,5 Inhibition of CYP epoxygenase-dependent AA metabolism results in the development of salt-sensitive hypertension^5,6; however, the BP returned to normal after the removal of the epoxygenase inhibitor, even when the animals were still kept on a high-Na diet. The high Na intake–induced increase in EET formation was defective in CYP4A10(−/−) mice.² Although CYP4A10 is not the enzyme responsible for generating EET, deleting the CYP4A10 gene impairs the expression of CYP epoxygenases, CYP2C44 in particular. Consequently, CYP4A10(−/−) mice had developed a salt-sensitive hypertension that was prevented by amiloride, suggesting that defective regulation of ENaC by CYP epoxygenase-dependent AA metabolism was responsible for the salt-sensitive hypertension in CYP4A(−/−) mice.² The expression of CYP2C44 or its ortholog is stimulated not only by high Na but also by high potassium (HK) intake.⁷ Because CYP2C44 is highly expressed in the connecting tubule and the CCD,¹ it is conceivable that a high expression of CYP2C44 should enhance the AA-induced inhibition of ENaC; therefore, the aim of this study was to examine whether HK intake enhances the CYP-epoxygenase–dependent inhibitory effect of AA on ENaC.     

Morphology of the medial collateral ligament of the knee

Background  

Quantitative knowledge on the anatomy of the medial collateral ligament (MCL) is important for treatment of MCL injury and for MCL release during total knee arthroplasty (TKA). The objective of this study was to quantitatively determine the morphology of the MCL of human knees.     

Inflammation‐induced preterm birth alters neuronal morphology in the mouse fetal brain

Adverse neurological outcome is a major cause of long‐term morbidity in ex‐preterm children. To investigate the effect of parturition and inflammation on the fetal brain, we utilized two in vivo mouse models of preterm birth. To mimic the most common human scenario of preterm birth, we used a mouse model of intrauterine inflammation by intrauterine infusion of lipopolysaccharide (LPS). To investigate the effect of parturition on the immature fetal brain, in the absence of inflammation, we used a non‐infectious model of preterm birth by administering RU486. Pro‐inflammatory cytokines (IL‐10, IL‐1β, IL‐6 and TNF‐α) in amniotic fluid and inflammatory biomarkers in maternal serum and amniotic fluid were compared between the two models using ELISA. Pro‐inflammatory cytokine expression was evaluated in the whole fetal brains from the two models. Primary neuronal cultures from the fetal cortex were established from the different models and controls in order to compare the neuronal morphology. Only the intrauterine inflammation model resulted in an elevation of inflammatory biomarkers in the maternal serum and amniotic fluid. Exposure to inflammation‐induced preterm birth, but not non‐infectious preterm birth, also resulted in an increase in cytokine mRNA in whole fetal brain and in disrupted fetal neuronal morphology. In particular, Microtubule‐associated protein 2 (MAP2) staining was decreased and the number of dendrites was reduced (P < 0.001, ANOVA between groups). These results suggest that inflammation‐induced preterm birth and not the process of preterm birth may result in neuroinflammation and alter fetal neuronal morphology. © 2010 Wiley‐Liss, Inc.     

Direct comparison of enoxaparin and nadroparin in a rabbit model of arterial thrombosis prevention

Introduction

The aim of the study was to evaluate and compare the efficacy of standard unfractionated heparin (UFH) and low-molecular weight heparins (LMWH's).

Materials and Methods

We modified a previously published rabbit model of arterial thrombosis prevention [1,2] to compare unfractionated heparin and two different doses of two low-molecular weight heparin fragments - nadroparin and enoxaparin. Thrombosis in the distal aorta was triggered by vessel wall injury and critical stenosis. Blood flow in the damaged arterial segment was monitored by a flow probe placed distal to the constrictor. The primary endpoints of the study were: (1) cumulative flow, (2) time to occlusion and (3) residual clot weight. Thirty six animals were split into 6 groups with six animals in each group. Control groups were given saline or heparin and four more groups were used to compare LMWH's at 2 different doses.

Results

In our study, all treatments were superior to the saline control group (α ≤ 0,01). Standard heparin was inferior (α ≤ 0,05) to both low molecular weight heparins for all primary endpoints (cumulative flow, time to occlusion and residual clot weight). There were no differences between the LMWH's except for cumulative flow at high doses.

Conclusions

This study revealed no relevant differences between nadroparin and enoxaparin for the primary endpoints of our model. Clinical use of each drug remains a personal preference.