Bioengineering of the digestive tract: approaching the clinic

The field of regenerative medicine is developing technologies that, in the near future, will offer alternative approaches to either cure diseases affecting the gastrointestinal tract or slow their progression by leveraging the intrinsic ability of our tissues and organs to repair after damage. This article will succinctly illustrate the three technologies that are closer to clinical translation—namely, human intestinal organoids, sphincter bioengineering and decellularization, whereby the cellular compartment of a given segment of the digestive tract is removed to obtain a scaffold consisting of the extracellular matrix. The latter will be used as a template for the regeneration of a functional organ, whereby the newly generated cellular compartment will be obtained from the patient's own cells. Although clinical application of this technology is approaching, product development challenges are being tackled to warrant safety and efficacy.     

p53 Dependent Apoptotic Cell Death Induces Embryonic Malformation in Carassius auratus under Chronic Hypoxia

Hypoxia is a global phenomenon affecting recruitment as well as the embryonic development of aquatic fauna. The present study depicts hypoxia induced disruption of the intrinsic pathway of programmed cell death (PCD), leading to embryonic malformation in the goldfish, Carrasius auratus. Constant hypoxia induced the early expression of pro-apoptotic/tumor suppressor p53 and concomitant expression of the cell death molecule, caspase-3, leading to high level of DNA damage and cell death in hypoxic embryos, as compared to normoxic ones. As a result, the former showed delayed 4 and 64 celled stages and a delay in appearance of epiboly stage. Expression of p53 efficiently switched off expression of the anti-apoptotic Bcl-2 during the initial 12 hours post fertilization (hpf) and caused embryonic cell death. However, after 12 hours, simultaneous downregulation of p53 and Caspase-3 and exponential increase of Bcl-2, caused uncontrolled cell proliferation and prevented essential programmed cell death (PCD), ultimately resulting in significant (p<0.05) embryonic malformation up to 144 hpf. Evidences suggest that uncontrolled cell proliferation after 12 hpf may have been due to downregulation of p53 abundance, which in turn has an influence on upregulation of anti-apoptotic Bcl-2. Therefore, we have been able to show for the first time and propose that hypoxia induced downregulation of p53 beyond 12 hpf, disrupts PCD and leads to failure in normal differentiation, causing malformation in gold fish embryos.     

Gadolinium-loaded polychelating polymer-containing cancer cell-specific immunoliposomes

Liposome loading with Gd via the membrane-incorporated polychelating amphiphilic polymers (PAPs) significantly increases the Gd content and relaxivity (T1 parameter) of PEGylated liposomes, which can be used as contrast agents for magnetic resonance imaging (MRI). Here, we demonstrate that such Gd-containing liposomes can be additionally modified with the monoclonal anticancer antibody 2C5 (mAb 2C5) possessing the nucleosome(NS)-restricted specificity via the PEG spacer. Liposome-bound antibody preserves its specific activity (ELISA) and such Gd-loaded PEGylated 2C5-immunoliposomes specifically recognize various cancer cells in vitro and target an increased amount of Gd to their surface compared to antibody-free Gd-liposomes or Gd-liposomes modified with tumor nonspecific antibody. Gd-loaded cancer cell-targeted immunoliposomes may represent promising agents for enhanced tumor MRI.     

"SMART" drug delivery systems: double-targeted pH-responsive pharmaceutical nanocarriers

To develop targeted pharmaceutical carriers additionally capable of responding to certain local stimuli, such as decreased pH values in tumors or infarcts, targeted long-circulating PEGylated liposomes and PEG-phosphatidylethanolamine (PEG-PE)-based micelles have been prepared with several functions. First, they are capable of targeting a specific cell or organ by attaching the monoclonal antimyosin antibody 2G4 to their surface via pNP-PEG-PE moieties. Second, these liposomes and micelles were additionally modified with biotin or TAT peptide (TATp) moieties attached to the surface of the nanocarrier by using biotin-PE or TATp-PE or TATp-short PEG-PE derivatives. PEG-PE used for liposome surface modification or for micelle preparation was made degradable by inserting the pH-sensitive hydrazone bond between PEG and PE (PEG-Hz-PE). Under normal pH values, biotin and TATp functions on the surface of nanocarriers were "shielded" by long protecting PEG chains (pH-degradable PEG(2000)-PE or PEG(5000)-PE) or by even longer pNP-PEG-PE moieties used to attach antibodies to the nanocarrier (non-pH-degradable PEG(3400)-PE or PEG(5000)-PE). At pH 7.4-8.0, both liposomes and micelles demonstrated high specific binding with 2G4 antibody substrate, myosin, but very limited binding on an avidin column (biotin-containing nanocarriers) or internalization by NIH/3T3 or U-87 cells (TATp-containing nanocarriers). However, upon brief incubation (15-30 min) at lower pH values (pH 5.0-6.0), nanocarriers lost their protective PEG shell because of acidic hydrolysis of PEG-Hz-PE and acquired the ability to become strongly retained on an avidin column (biotin-containing nanocarriers) or effectively internalized by cells via TATp moieties (TATp-containing nanocarriers). We consider this result as the first step in the development of multifunctional stimuli-sensitive pharmaceutical nanocarriers.     

Vasospasm is a significant factor in cyclosporine-induced neurotoxicity: Case report

Background

The aetiology of central nervous system lesions observed in cerebral cyclosporine neurotoxicity remains controversial.

Case presentation

We report a 48-year-old woman with a non-severe aplastic anaemia who presented with stroke-like episodes while on cyclosporine treatment.Transcranial Doppler ultrasound revealed severely elevated flow velocities in several cerebral vessels, consistent with vasospasm. Immediately after reducing the cyclosporine dose, the stroke-like episodes disappeared. Only after cyclosporine withdrawal the transcranial Doppler ultrasound abnormalities fully resolved.

Conclusions

This case demonstrates a significant role of vasospasm in the pathway of cyclosporine-induced neurotoxicity. Transcranial Doppler ultrasound is an effective tool for the diagnosis and follow-up of cyclosporine-induced vasospasm.

     

Development and characterization of new cell line BPH22 from midgut epithelial cells of <Emphasis Type="Italic">Poekilocerus pictus</Emphasis> (Fabricius, 1775)

Poekilocerus pictus is a painted grasshopper, which feeds on Calotropis sp. containing the cardiac glycosides. A new cell line BPH22 is developed from midgut of P. pictus to study its unique physiology and biochemistry. Initially, the Graces insect medium is used with 10% (v/v) fetal bovine serum. After four passages, the serum quantity was reduced up to 0%.The lag phase in growth curve was 5 d and log phase is up to 10–11 d. The addition of Calotropis extract in Graces medium enhanced the growth of cells. The Calotropis extract with Graces medium altered the morphology of cells of BPH22. The amplification and sequencing of 16S rRNA gene confirmed the origin and purity of the BPH22.     

Multifunctionality of lipid-core micelles for drug delivery and tumour targeting

Phospholipid micelles have proven to be the versatile pharmaceutical nanocarrier of choice for the delivery of poorly soluble chemotherapeutics for cancer therapy using various treatment modalities. Phospholipid micelles are typically expected to increase the accumulation of the loaded drugs in tumour tissues by taking advantage of the enhanced permeability and retention effect and by ligand-mediated active targeting. Furthermore, by tailoring the composition of the micelles, it is possible to enhance the intracellular delivery of the cargo. This review highlights the important advancements in our laboratory with polyethyleneglycol phosphatidylethanolamine (PEG-PE)-based micellar drug delivery systems for improvement of the therapeutic efficacy of poorly soluble anticancer drugs.     

Application quantum and physico chemical molecular descriptors utilizing principal components to study mode of anticoagulant activity of pyridyl chromen-2-one derivatives

Factors II, V, VII and Xa have materialized as a key enzymes for the intervention of blood coagulation cascade and for the development of new anti thrombotic agents. The combined density functional quantum mechanical/molecular mechanical (QM/MM) approach has been used to access inhibition of prothrombin and thrombin production. The biological activities of coumarin derivatives as clotting factor inhibitors was quantitatively analyzed in terms of physicochemical parameters utilizing the principal component analysis. Structural requirements for maximal potency were derived from the results of a quantitative structure activity relationship analysis.