Renal Replacement Therapy for Acute Kidney Injury in Severe Alcohol-Associated Hepatitis as a Bridge to Transplant or Recovery

Digestive Diseases and Sciences - Acute kidney injury is seen in approximately 30% of patients with severe alcohol-associated hepatitis (AH) and is associated with increased mortality. Controversy...     

Electrophysiological properties of mouse bone marrow c-kit+ cells co-cultured onto neonatal cardiac myocytes

OBJECTIVE: Controversy about hematopoietic stem cells reprogramming into cardiac myocytes is currently supported by positive and negative findings. In fact, some reports have shown the ability of stem cells from the bone marrow (BM) to differentiate into cardiac myocytes and to contribute to myocardium repair, while others have reported the opposite. METHODS: C-kit(+) cells from mouse bone marrow were co-cultured onto neonatal cardiac myocytes. Hematopoietic stem cell-derived cells were analyzed by investigating the expression of cardiac markers and ion channels and by single-cell electrophysiological recordings. RESULTS: Groups of undifferentiated c-kit(+) cells displayed only outward currents. Co-cultured c-kit(+) stem cells on neonatal cardiac myocytes expressed cardiac markers and Na(+) and Ca(2+) voltage-gated ion channels. However, Na(+) and Ca(2+) currents were not detected by electrophysiological patch-clamp recordings even if caffeine and cyclopiazonic acid treatment showed the presence of intracellular calcium stores. This suggests that these channels, although expressed, were not functional and thus do not allow the coupling between excitation and contraction that is typical of cardiac myocytes. Nevertheless, co-cultured cells had a more hyperpolarized resting membrane potential and, at least in a subset of cells, displayed voltage-gated inward rectifier currents and outward currents. Co-cultured c-kit(+)-derived cells were not connected to surrounding cardiac myocytes through gap junctions. To induce a more pronounced differentiation, co-cultured cells were treated with BMP-4 and TGF-beta, two factors that were shown to trigger a cardiac myocyte differentiation pathway in embryonic stem (ES) cells. Even under these conditions, c-kit(+) cells did not differentiate into functionally active cardiac myocytes. However, TGF-beta/BMP-4-treated cells were hyperpolarized and showed and increased inward rectifier current density. CONCLUSIONS: Our study shows that mouse BM hematopoietic stem cells exhibit a limited plasticity to transdifferentiate into cardiac myocytes in culture.     

Keratoconus staging: a computer-assisted ultrabiomicroscopic method compared with videokeratographic analysis

PURPOSE: The aim of this study was to introduce a new paradigm for keratoconus assessment, the keratoconus index (KI), generated from the ratio of peripheral corneal thickness (PCT) to the thinnest corneal thickness (TCT), and calculated by a computer-assisted procedure after ultrabiomicroscope (UBM) examination. Then we compared KI and the keratoconus severity index (KSI), obtained by videokeratography in patients with different stages of keratoconus. METHODS: We studied 60 eyes with different forms of keratoconus using the TMS-3 autotopographer, provided with a keratoconus screening program (using Smolek-Klyce methods) and the commercial version of the ultrasound biomicroscope (Paradigm UBM Plus Model P45) equipped with a 50-MHz probe, which was provided with our computer-assisted program. The proportion test Z and the correlation coefficient R were applied to the outcomes. RESULTS: The keratoconus severity index, KSI, obtained by color-coded videokeratographic maps, was in the range 95% to 32% (mean 52.22%). By means of UBM examination, we obtained 60 images and found values of TCT 0.278-0.592 mm and PCT 0.475-0.704 mm. Applying the computer-assisted method, we obtained values for KI of 1.112-2.159 (mean 1.428). CONCLUSIONS: KI is correlated as well as KSI with the severity of the keratoconus (R = 0.76, P < 0.0001). It can be used as a similar parameter to measure the evolution of the disease, on the basis of corneal thickness rather than the curvature.     

Cardioprotective stimuli mediate phosphoinositide 3-kinase and phosphoinositide dependent kinase 1 nuclear accumulation in cardiomyocytes

The phosphoinositide 3-kinase (PI3K)/phosphoinositide dependent kinase 1 (PDK1) signaling pathway exerts cardioprotective effects in the myocardium through activation of key proteins including Akt. Activated Akt accumulates in nuclei of cardiomyocytes suggesting that biologically relevant targets are located in that subcellular compartment. Nuclear Akt activity could be potentiated in both intensity and duration by the presence of a nuclear-associated PI3K/PDK1 signaling cascade as has been described in other non-myocyte cell types. PI3K/PDK1 distribution was determined in vitro and in vivo by immunostaining and nuclear extraction of cultured rat neonatal cardiomyocytes or transgenic mouse hearts. Results show that PI3K and PDK1 are present at a basal level in cardiomyocytes nuclei and that cardioprotective stimulation with atrial natriuretic peptide (ANP) increases their nuclear localization. In comparison, overexpression of nuclear-targeted Akt does not mediate increased translocation of either PI3K or PDK1 indicating that accumulation of Akt does not drive PI3K or PDK1 into the nuclear compartment. Furthermore, PI3K and phospho-Akt⁴⁷³ show parallel temporal accumulation in the nucleus following (MI) infarction challenge. These findings demonstrate the presence of a dynamically regulated nuclear-associated signaling cascade involving PI3K and PDK that presumably influences nuclear Akt activation.     

Oral desensitisation with food is food-specific and protein-specific

The avoidance of food(s) is the main therapeutic approach to food allergy. Nevertheless, orally- or sublingually-administered food allergens have gained attention and a number of food-allergic children can tolerate gradually increasing amounts of cow's milk and hen's egg. Our purpose is to show that oral desensitisation with food is an allergen-specific therapeutic approach and for this, we describe 4 illustrative children with IgE-mediated food allergy. The first was allergic to cow's milk and hen's egg, the second to cow's milk, hen's egg and fish. Both underwent oral desensitisation to both cow's milk and hen's egg. The third child was allergic to cow's milk, hen's egg and fish and underwent oral desensitisation with cow's milk. The last child was allergic to raw but not to cooked/boiled hen's egg and underwent the oral desensitisation with hen's egg. The first 2 children reached the clinical tolerance to cow's milk after the cow's milk oral desensitisation, but reached the hen's egg tolerance only after the hen's egg oral desensitisation. Moreover, the second child did not tolerate fish after being desensitised to both cow's milk and hen's egg. The third child tolerated cow's milk, but not hen's egg and fish, at the end of the cow's milk oral desensitisation. The fourth child could tolerate the previously not tolerated raw hen's egg after the oral desensitisation with raw hen's egg. In conclusion, we indicate that oral desensitisation with food is allergen specific. The induction of the clinical tolerance to one food is not followed by the tolerance to the other food(s) that the patient is allergic to. To obtain a double or multiple food tolerance, separate desensitisation protocols, one for each food, have to be carried out. Oral desensitisation with food discriminates between raw and cooked proteins.     

Optic disc drusen, angioid streaks, and mottled fundus in various combinations in a Sicilian family

BACKGROUND: We describe a Sicilian family in which optic disc drusen, angioid streaks, and mottled fundus--without dermatological signs of pseudoxanthoma elasticum (PXE)--are present in various combinations and segregate as an autosomal dominant trait. Since these ocular manifestations can be part of the clinical signs of PXE, we examined the possible involvement of a mutation in the ABCC6 gene, which is known to be responsible for PXE. METHODS: Linkage analysis was performed with both intragenic and flanking markers. We used marker D16B9722 and a single-nucleotide polymorphism located in exon 15 of the ABCC6 gene. LOD score values were calculated on the assumption of a gene frequency of 0.0001 and both complete penetrance and reduced penetrance (90%), with theta values between 0.0 and 0.4. RESULTS: LOD score values excluded the involvement of the ABCC6 gene. CONCLUSIONS: The dominant transmission of optic disc drusen, mottled fundus, and angioid streaks in this family is not due to alterations in the ABCC6 gene.     

The multipartite system that mediates entry of herpes simplex virus into the cell

The multipartite entry-fusion system of herpes simplex virus is made of a quartet of glycoproteins-gD, gB, gH.gL-and three alternative gD receptors, herpesvirus entry mediator (HVEM), nectin1 and modified sites on heparan sulphate. This multipartite system recapitulates the basic steps of virus-cell fusion, i.e. receptor recognition, triggering of fusion and fusion execution. Specifically, in addition to serving as the receptor-binding glycoprotein, gD triggers fusion through a specialised domain, named pro-fusion domain (PFD), located C-terminally in the ectodomain. In the unliganded gD the C-terminal region folds around the N-terminal region, such that gD adopts a closed autoinhibited conformation. In HVEM- and nectin1-bound gD the C-terminal region is displaced (opened conformation). gD is the tool for modification of HSV tropism, through insertion of ligands to heterologous tumour-specific receptors. It is discussed whether gD responds to the interaction with the natural and the heterologous receptors by adopting similar conformations, and whether the closed-to-open switch in conformation is a generalised mechanism of activation. A peculiar recombinant highlighted that the central Ig-folded core of gD may not encode executable functions for entry and that the 219-314 aa segment may be sufficient to trigger fusion. With respect to fusion execution, gB appears to be a prospective fusogen based on its coiled-coil trimeric structure, similar to that of another fusion glycoprotein. On the other hand, gH exhibits molecular elements typical of class 1 fusion glycoproteins, in particular heptad repeats and strong tendency to interact with lipids. Whether fusion execution is carried out by gB or gH.gL, or both glycoproteins in complex or sequentially remains to be determined.