Simulation of non-inherited maternal antigens acceptable HLA mismatches to increase the chance of matched cord blood units: Hong Kong’s experience

In Cord blood transplantation (CBT), the non-inherited maternal antigen (NIMA) virtual six HLA matched CB is found to have similar outcomes to six HLA inherited matched CB. Such virtual HLA matched CB units can be generated by substituting the inherited alleles with one to three NIMAs. In Hong Kong Cord Blood Bank, CB units have no NIMA defined. 100 CB samples were collected with NIMA defined. Retrospective searches of Hong Kong patients (n?=?520) were matched against the inherited and virtual HLA phenotypes of NIMA CB file. One to three NIMA matches was analyzed, virtual six HLA matches were identified for 31.7% patients, 29.4% from CB units with 5/6 HLA match with 1 NIMA match and 1.7% CB units with a 4/6 HLA match and 2 NIMA matches. However, searches in the 167,201 Bone Marrow Donors Worldwide CB units with defined NIMA did not yield similar increases, possibly due to the ethnicity differences between populations. The match performance rises from 26% to 60% after including the NIMA match. Comparing the match performance of 32% in a previous Dutch study, we calculated with 60% matching in this smaller size study. This provides a solid ground to considering NIMA in stem cell donor selection which was adopted in some centers, to be extended to Asian and local CB registries to increase the chance for matches and also to improve patient outcomes, increase the utilization of CB units, enhance clinical flexibility and signify economic intelligence.     

Epstein–Barr virus‐positive post‐transplant lymphoproliferative disorder of the central nervous system,after renal transplantation with a discrepancy in viral load between peripheral blood and cerebrospinal fluid

A 43‐year‐old female developed an Epstein–Barr virus (EBV)‐positive post‐transplant lymphoproliferative disorder (PTLD) in the central nervous system (CNS), 14 years after renal transplantation. One year prior to presentation, the patients’ treatment regimen was altered from cyclosporine, azathioprine, and prednisone to mycophenolate mofetil and prednisone. Magnetic resonance imaging of the brain revealed lesions suspect for malignant lymphoma. The EBV real‐time polymerase chain reaction (PCR) on peripheral blood was negative, but highly positive on cerebrospinal fluid. EBV‐positive PTLD was confirmed using histological analysis of cerebral biopsies. Despite tapering of immune suppressive medication and treatment with rituximab and chemotherapy, the patient deceased 50 days after presentation. This case illustrates that vigilance is required when presented with a negative EBV PCR result on peripheral blood when PTLD of the CNS is suspected. This late presentation suggests a relation to the switch in immunosuppressive regimen 1 year earlier.     

Refocusing on the gynecological and obstetrical consequences of intrauterine exposure to diethylstilbestrol (DES)

The oncological and obstetrical follow-up is described of 321 patients who presented between 1981 and 1988 in the St Radboud Hospital with a history of intrauterine diethylstilbestrol(DES) exposure. In 45 out of 321 cases cytological abnormalities were found including 20 cases of cervical intraepithelial neoplasia (CIN). No relation could be established between CIN and the extension of the cervical adenosis. Twenty-two percent of 87 evaluable pregnancies terminated in spontaneous abortion, 13 percent of the patients delivered immaturely and 27 percent prematurely. These percentages were significantly higher than in the rest of the hospital population. The consequences of intrauterine exposure to DES are discussed. Full examination of the patients is advised, including colposcopy and hysterosalpingography. If abnormalities are present it is advised to offer a timely cerclage in case of pregnancy.     

Drinking behavior in the spiny mouse (Acomys cahirinus) following putative dipsogenic challenges

Male spiny mice (Acomys cahirinus) were challenged with several putative dipsogenic stimulus conditions: hypertonic sodium chloride (NaCl), 24-h water deprivation, d,l-isoproterenol HCl, angiotensin II (AII) and polyethylene glycol (PEG), or control conditions, in within-subjects designs. Water intake and drinking pattern were monitored electronically in the home cage over a 2--6-h test period without food present, during the light portion of the L/D cycle. In addition, hematocrits were measured following several treatments and mean arterial blood pressure was monitored in response to several doses of AII. As expected, both water deprivation and hypertonic NaCl led to robust drinking with short latencies. PEG was also an effective dipsogen; while quite variable, latencies were often shorter than are typically reported for the rat. Isoproterenol induced a modest, but significant, dose-related drinking. Interference by AII's prominent pressor action might account, at least in part, for its relative ineffectiveness as a dipsogen. Comparisons are made with other rodent species similarly challenged.     

Inhibition of multidrug resistance proteins MRP1 and MRP2 by a series of alpha,beta-unsaturated carbonyl compounds

To study the possible interplay between glutathione metabolism of and MRP inhibition by thiol reactive compounds, the interactions of a series of alpha,beta-unsaturated carbonyl compounds with multidrug resistance proteins 1 and 2 (MRP1/ABCC1 and MRP2/ABCC2) were studied. Alpha,beta-unsaturated carbonyl compounds react with glutathione, and therefore either their parent compound or their intracellularly formed glutathione metabolite(s) can modulate MRP-activity. Inhibition was studied in Madin-Darby canine kidney cells stably expressing MRP1 or MRP2, and isolated Sf9-MRP1 or Sf9-MRP2 membrane vesicles. In the latter model system metabolism is not an issue. Of the series tested, three distinct groups could be discriminated based on differences in interplay of glutathione metabolism with MRP1 inhibition. Curcumin inhibited MRP1 transport only in the vesicle model pointing at inhibition by the parent compound. The glutathione conjugates of curcumin also inhibit MRP1 mediated transport, but to a much lesser extent than the parent compound curcumin. In the cellular model system, it was demonstrated that glutathione conjugation of curcumin leads to inactivation of its inhibitory potential. Demethoxycurcumin and bisdemethoxycurcumin inhibited MRP1 in both the vesicle and cellular model pointing at inhibitory potency of at least the parent compound and possibly their metabolites. A second group, including caffeic acid phenethyl ester inhibited MRP1-mediated calcein transport only in the MDCKII-MRP1 cells, and not in the vesicle model indicating that metabolism appeared a prerequisite to generate the active inhibitor. Finally cinnamaldehyde, crotonaldehyde, trans-2-hexanal, citral, and acrolein did not inhibit MRP1. For MRP2, inhibition was much less in both model systems, with the three curcuminoids being the most effective. The results of this study show the importance to study the complex interplay between MRP-inhibitors and their cellular metabolism, the latter affecting the ultimate potential of a compound for cellular MRP-inhibition.     

Quantitative structure activity relationship studies on the flavonoid mediated inhibition of multidrug resistance proteins 1 and 2

In the present study, the effects of a large series of flavonoids on multidrug resistance proteins (MRPs) were studied in MRP1 and MRP2 transfected MDCKII cells. The results were used to define the structural requirements of flavonoids necessary for potent inhibition of MRP1- and MRP2-mediated calcein transport in a cellular model. Several of the methoxylated flavonoids are among the best MRP1 inhibitors (IC(50) values, ranging between 2.7 and 14.3 microM) followed by robinetin, myricetin and quercetin (IC(50) values ranging between 13.6 and 21.8 microM). Regarding inhibition of MRP2 activity especially robinetin and myricetin appeared to be good inhibitors (IC(50) values of 15.0 and 22.2 microM, respectively). Kinetic characterization revealed that the two transporters differ marginally in the apparent K(m) for the substrate calcein. For one flavonoid, robinetin, the kinetics of inhibition were studied in more detail and revealed competitive inhibition with respect to calcein, with apparent inhibition constants of 5.0 microM for MRP1 and 8.5 microM for MRP2. For inhibition of MRP1, a quantitative structure activity relationship (QSAR) was obtained that indicates three structural characteristics to be of major importance for MRP1 inhibition by flavonoids: the total number of methoxylated moieties, the total number of hydroxyl groups and the dihedral angle between the B- and C-ring. Regarding MRP2 mediated calcein efflux inhibition, only the presence of a flavonol B-ring pyrogallol group seems to be an important structural characteristic. Overall, this study provides insight in the structural characteristics involved in MRP inhibition and explores the differences between inhibitors of these two transporters, MRP1 and MRP2. Ultimately, MRP2 displays higher selectivity for flavonoid type inhibition than MRP1.     

Selective α7 nicotinic acetylcholine receptor agonists worsen disease in experimental colitis

Background and purpose:

In various models vagus nerve activation has been shown to ameliorate intestinal inflammation, via nicotinic acetylcholine receptors (nAChRs) expressed on immune cells. As the α7 nAChR has been put forward to mediate this effect, we studied the effect of nicotine and two selective α7 nAChR agonists (AR-{"type":"entrez-nucleotide","attrs":{"text":"R17779","term_id":"771389","term_text":"R17779"}}R17779, (-)-spiro[1-azabicyclo[2.2.2] octane-3,5′-oxazolidin-2′-one and GSK1345038A) on disease severity in two mouse models of experimental colitis.

Experimental approach:

Colitis was induced by administration of 1.5% dextran sodium sulphate (DSS) in drinking water or 2 mg 2,4,6-trinitrobenzene sulphonic acid (TNBS) intrarectally. Nicotine (0.25 and 2.50 µmol·kg⁻¹), AR-{"type":"entrez-nucleotide","attrs":{"text":"R17779","term_id":"771389","term_text":"R17779"}}R17779 (0.6–30 µmol·kg⁻¹) or GSK1345038A (6–120 µmol·kg⁻¹) was administered daily by i.p. injection. After 7 (DSS) or 5 (TNBS) days clinical parameters and colonic inflammation were scored.

Key results:

Nicotine and both α7 nAChR agonists reduced the activation of NF-κB and pro-inflammatory cytokines in whole blood and macrophage cultures. In DSS colitis, nicotine treatment reduced colonic cytokine production, but failed to reduce disease parameters. Reciprocally, treatment with AR-{"type":"entrez-nucleotide","attrs":{"text":"R17779","term_id":"771389","term_text":"R17779"}}R17779 or GSK1345038A worsened disease and led to increased colonic pro-inflammatory cytokine levels in DSS colitis. The highest doses of GSK1345038A (120 µmol·kg⁻¹) and AR-{"type":"entrez-nucleotide","attrs":{"text":"R17779","term_id":"771389","term_text":"R17779"}}R17779 (30 µmol·kg⁻¹) ameliorated clinical parameters, without affecting colonic inflammation. Neither agonist ameliorated TNBS-induced colitis.

Conclusions and implications:

Although nicotine reduced cytokine responses in vitro, both selective α7 nAChR agonists worsened the effects of DSS-induced colitis or were ineffective in those of TNBS-induced colitis. Our data indicate the need for caution in evaluating α7 nAChR as a drug target in colitis.