Hyaluronic acid-human blood hydrogels for stem cell transplantation

Tissue engineering-based approaches have the potential to improve stem cell engraftment by increasing cell delivery to the myocardium. Our objective was to develop and characterize a naturally-derived, autologous, biodegradable hydrogel in order to improve acute stem cell retention in the myocardium. HA-blood hydrogels (HA-BL) were synthesized by mixing in a 1:1(v/v) ratio, lysed whole blood and hyaluronic acid (HA), whose carboxyl groups were functionalized with N-hydroxysuccinimide (NHS) to yield HA succinimidyl succinate (HA-NHS). We performed physical characterization and measured survival/proliferation of cardiosphere-derived cells (CDCs) encapsulated in the hydrogels. Hydrogels were injected intra-myocardially or applied epicardially in rats. NHS-activated carboxyl groups in HA react with primary amines present in blood and myocardium to form amide bonds, resulting in a 3D hydrogel bound to tissue. HA-blood hydrogels had a gelation time of 58?±?12?s, swelling ratio of 10?±?0.5, compressive and elastic modulus of 14?±?3 and 1.75?±?0.6?kPa respectively. These hydrogels were not degraded at 4wks by hydrolysis alone. CDC encapsulation promoted their survival and proliferation. Intra-myocardial injection of CDCs encapsulated in these hydrogels greatly increased acute myocardial retention (p?=?0.001). Epicardial application of HA-blood hydrogels improved left ventricular ejection fraction following myocardial infarction (p?=?0.01). HA-blood hydrogels are highly adhesive, biodegradable, promote CDC survival and increase cardiac function following epicardial application after myocardial infarction.     

Lack of evidence for appetitive effects of Delta 9-tetrahydrocannabinol in the intracranial self-stimulation and conditioned place preference procedures in rodents

Data on the ability of Delta 9-tetrahydrocannabinol (THC) to modify reward processes in experimental animals are inconsistent. This study examined the effects of Delta 9-THC on brain reward function using the rate-frequency curve shift paradigm of intracranial self-stimulation (ICSS) and the conditioned place preference (CPP) paradigm. In ICSS tests, rats were implanted with electrodes into the medial forebrain bundle. After brain stimulation reward thresholds stabilized, rats received intraperitoneal injections of Delta 9-THC (0, 0.5, 1 and 2 mg/kg) or the CB1 receptor antagonist SR141716A (0, 0.02 mg/kg) and Delta 9-THC (0, 2 mg/kg). The two highest doses of Delta 9-THC significantly increased the threshold ICSS frequency. SR141716A reversed the action of Delta 9-THC (2 mg/kg), without affecting reward thresholds by itself. In the CPP test, mice received intraperitoneal injections of Delta 9-THC (0, 1 or 3 mg/kg). Delta 9-THC showed neither statistically significant preference nor aversion in either of the doses tested. These findings indicate that Delta 9-THC, in contrast to other drugs of abuse, does not facilitate ICSS or support CPP under the present experimental conditions, but rather has a dose-dependent inhibitory influence on ICSS.     

Reprogramming of murine and human somatic cells using a single polycistronic vector

Directed reprogramming of somatic cells by defined factors provides a novel method for the generation of patient-specific stem cells with the potential to bypass both the practical and ethical concerns associated with somatic cell nuclear transfer (SCNT) and human embryonic stem (hES) cells. Although the generation of induced pluripotent stem (iPS) cells has proven a robust technology in mouse and human, a major impediment to the use of iPS cells for therapeutic purposes has been the viral-based delivery of the reprogramming factors because multiple proviral integrations pose the danger of insertional mutagenesis. Here we report a novel approach to reduce the number of viruses necessary to reprogram somatic cells by delivering reprogramming factors in a single virus using 2A “self-cleaving” peptides, which support efficient polycistronic expression from a single promoter. We find that up to four reprogramming factors (Oct4, Sox2, Klf4, and c-Myc) can be expressed from a single virus to generate iPS cells in both embryonic and adult somatic mouse cells and we show that a single proviral copy is sufficient to generate iPS cells from mouse embryonic fibroblasts. In addition we have generated human induced pluripotent stem (hiPS) cell lines from human keratinocytes, demonstrating that a single polycistronic virus can reprogram human somatic cells.     

Toll-like receptor 9 activation: a novel mechanism linking placenta-derived mitochondrial DNA and vascular dysfunction in pre-eclampsia

Emerging evidence suggests that in addition to being the 'power houses' of our cells, mitochondria facilitate effector responses of the immune system. Cell death and injury result in the release of mtDNA (mitochondrial DNA) that acts via TLR9 (Toll-like receptor 9), a pattern recognition receptor of the immune system which detects bacterial and viral DNA but not vertebrate DNA. The ability of mtDNA to activate TLR9?in a similar fashion to bacterial DNA stems from evolutionarily conserved similarities between bacteria and mitochondria. mtDNA may be the trigger of systemic inflammation in pathologies associated with abnormal cell death. PE (pre-eclampsia) is a hypertensive disorder of pregnancy with devastating maternal and fetal consequences. The aetiology of PE is unknown and removal of the placenta is the only effective cure. Placentas from women with PE show exaggerated necrosis of trophoblast cells, and circulating levels of mtDNA are higher in pregnancies with PE. Accordingly, we propose the hypothesis that exaggerated necrosis of trophoblast cells results in the release of mtDNA, which stimulates TLR9 to mount an immune response and to produce systemic maternal inflammation and vascular dysfunction that lead to hypertension and IUGR (intra-uterine growth restriction). The proposed hypothesis implicates mtDNA in the development of PE via activation of the immune system and may have important preventative and therapeutic implications, because circulating mtDNA may be potential markers of early detection of PE, and anti-TLR9 treatments may be promising in the management of the disease.     

Rupture of right hepatic duct into hydatid cyst

Echinococcal disease can develop anywhere in the human body. The liver represents its most frequent location. Hepatic hydatid cysts may rupture into the biliary tract, thorax, peritoneum, viscera, digestive tract or skin. We report a rare case with rupture of the right hepatic duct into a hydatid cyst in a woman with known hydatid disease and choledocholithiasis. The increased intra-luminal pressure in the biliary tree caused the rupture into the adjacent hydatid cyst. The creation of the fistula between the right hepatic duct and the hydatid cyst decompressed the biliary tree, decreased the bilirubin levels and offered a temporary resolution of the obstructive jaundice. Rupture of a hydatid cyst into the biliary tree usually leads to biliary colic, cholangitis and jaundice. However, in case of obstructive jaundice due to choledocholithiasis, it is possible that the cyst may rupture by other way around while offering the patient a temporary relief from his symptoms.     

Alzheimer’s Disease: New Concepts on the Role of Autoimmunity and NLRP3 Inflammasome in the Pathogenesis of the Disease

Alzheimer’s disease (AD), recognized as the most common neurodegenerative disorder, is clinically characterized by the presence of extracellular beta-amyloid (Aβ) plaques and by intracellular neurofibrillary tau tangles, accompanied by glial activation and neuroinflammation. Increasing evidence suggests that self-misfolded proteins stimulate an immune response mediated by glial cells, inducing the release of inflammatory mediators and the recruitment of peripheral macrophages into the brain, which in turn aggravate AD pathology.The present review aims to update the current knowledge on the role of autoimmunity and neuroinflammation in the pathogenesis of the disease, indicating a new target for therapeutic intervention. We mainly focused on the NLRP3 microglial inflammasome as a critical factor in stimulating innate immune responses, thus sustaining chronic inflammation. Additionally, we discussed the involvement of the NLRP3 inflammasome in the gut-brain axis. Direct targeting of the NLRP3 inflammasome and the associated receptors could be a potential pharmacological strategy since its inhibition would selectively reduce AD neuroinflammation.     

Nasal continuous positive airway pressure (nCPAP) treatment for obstructive sleep apnea, road traffic accidents and driving simulator performance: a meta-analysis

We used meta-analysis to synthesize current evidence regarding the effect of nasal continuous positive airway pressure (nCPAP) on road traffic accidents in patients with obstructive sleep apnea (OSA) as well as on their performance in driving simulator. The primary outcomes were real accidents, near miss accidents, and accident-related events in the driving simulator. Pooled odds ratios (ORs), incidence rate ratios (IRRs) and standardized mean differences (SMDs) were appropriately calculated through fixed or random effects models after assessing between-study heterogeneity. Furthermore, risk differences (RDs) and numbers needed to treat (NNTs) were estimated for real and near miss accidents. Meta-regression analysis was performed to examine the effect of moderator variables and publication bias was also evaluated. Ten studies on real accidents (1221 patients), five studies on near miss accidents (769 patients) and six studies on the performance in driving simulator (110 patients) were included. A statistically significant reduction in real accidents (OR = 0.21, 95% CI = 0.12–0.35, random effects model; IRR = 0.45, 95% CI = 0.34–0.59, fixed effects model) and near miss accidents (OR = 0.09, 95% CI = 0.04–0.21, random effects model; IRR = 0.23, 95% CI = 0.08–0.67, random effects model) was observed. Likewise, a significant reduction in accident-related events was observed in the driving simulator (SMD = −1.20, 95% CI = −1.75 to −0.64, random effects). The RD for real accidents was −0.22 (95% CI = −0.32 to −0.13, random effects), with NNT equal to five patients (95% CI = 3–8), whereas for near miss accidents the RD was −0.47 (95% CI = −0.69 to −0.25, random effects), with NNT equal to two patients (95% CI = 1–4). For near miss accidents, meta-regression analysis suggested that nCPAP seemed more effective among patients entering the studies with higher baseline accident rates. In conclusion, all three meta-analyses demonstrated a sizeable protective effect of nCPAP on road traffic accidents, both in real life and virtual environment.