A low-risk ZnT-8 allele (W325) for post-transplantation diabetes mellitus is protective against cyclosporin A-induced impairment of insulin secretion.

SLC30A8 encodes the ß-cell-specific zinc transporter-8 (ZnT-8) expressed in insulin secretory granules. The single-nucleotide polymorphism rs13266634 of SLC30A8 is associated with susceptibility to post-transplantation diabetes mellitus (PTDM). We tested the hypothesis that the polymorphic residue at position 325 of ZnT-8 determines the susceptibility to cyclosporin A (CsA) suppression of insulin secretion. INS (insulinoma)-1E cells expressing the W325 variant showed enhanced glucose-stimulated insulin secretion (GSIS) and were less sensitive to CsA suppression of GSIS. A reduced number of insulin granule fusion events accompanied the decrease in insulin secretion in CsA-treated cells expressing ZnT-8 R325; however, ZnT-8 W325-expressing cells exhibited resistance to the dampening of insulin granule fusion by CsA, and transported zinc ions into secretory vesicles more efficiently. Both tacrolimus and rapamycin caused similar suppression of GSIS in cells expressing ZnT-8 R325. However, cells expressing ZnT-8 W325 were resistant to tacrolimus, but not to rapamycin. The Down's syndrome candidate region-1 (DSCR1), an endogenous calcineurin inhibitor, overexpression and subsequent calcineurin inhibition significantly reduced GSIS in cells expressing the R325 but not the W325 variant, suggesting that differing susceptibility to CsA may be due to different interactions with calcineurin. These data suggest that the ZnT-8 W325 variant is protective against CsA-induced suppression of insulin secretion. Tolerance of ZnT-8 W325 to calcineurin activity may account for its protective effect in PTDM.

Correlation between the immature characteristics of umbilical cord blood-derived mesenchymal stem cells and engraftment of hematopoietic stem cells in NOD/SCID mice.

Umbilical cord blood (UCB)-derived mesenchymal stem cells (MSC) facilitate the engraftment of human (h) hematopoietic stem cells when transplanted simultaneously in animal and human studies. However, the type of MSCs that preferentially enhance the engraftment of HSCs is unknown. Recent studies have shown that MSCs derived from a single source are heterogeneous in terms of cell size, morphology, proliferation rate, and differentiation potential. This study was designed to investigate the properties of UCB-MSCs, which influence the engraftment of hHSCs in a NOD/SCID mouse model. We categorized MSCs as being the most effective (UCB-352 MSCs) or the least effective (UCB-156 MSCs) at promoting the homing and engraftment of HSCs, and compared the characteristics of these 2 MSC populations. We observed that the 2 populations showed differences in characteristics typical of immature MSCs, and related to proliferation potential. We showed that UCB-352 MSCs, which proliferate quickly, preferentially enhanced the engraftment of HSCs in NOD/SCID mice. In addition, we observed differences in the pattern of both PODXL and Oct4 expression, and in the levels of cytokines such as SDF-1 and SCF using flow cytometry and membrane arrays. The more effective UCB-352 MSCs expressed higher levels of PODXL and Oct4, which were associated with immaturity, than did the UCB-156 MSCs. Furthermore, UCB-352 cells secreted greater levels of SDF-1 and SCF, both of which are required for hematopoiesis. We propose that the proliferation potential of UCB-MSCs, coupled with their immature characteristics, may serve as a novel standard to promote the homing and engraftment of HSCs.

The genetics of lupus.

The complex multifactorial inheritance pattern of systemic lupus erythematosus in various murine models has been dissected via both classic genetic analysis and the use of modern technologies in genomic manipulation. Current information suggests that lupus may be mediated by a multitude of genetic abnormalities that impact on specific checkpoints in a three-step pathogenic pathway. These steps are as follows: loss of immunologic tolerance to nuclear antigens; the transition to pathogenic autoimmunity; and end-organ targeting. The identities of the genes that are responsible for transition between the specific steps of the pathway are still unknown and will require further study. However, several recent findings have provided insights into specific elements in each stage of lupus. These findings suggest that mouse models of lupus may provide valuable insights into the genetic basis of human systemic lupus erythematosus.

Infected hydrocele in a neonate.

A case of infected hydrocele in a neonate is presented. We describe this unusual condition, and discuss the diagnosis, pathophysiology and treatment.

Hemiparesis and ischemic changes of the white matter after intrathecal therapy for children with acute lymphocytic leukemia.

Three children with acute lymphocytic leukemia (ALL) developed delayed-onset transient hemiparesis and facial palsy after intrathecal (IT) administration of methotrexate (MTX) alone or as part of triple intrathecal chemotherapy for central nervous system (CNS) prophylaxis. The hemiparesis developed 10 to 14 days after IT therapy. Two of three children also experienced transient, profound expressive dysarthria. These episodes occurred during maintenance treatment after multiple IT administrations and without previous CNS toxicity. Two of three children received intermediate-dose MTX, 1 g/m2, not less than 5 weeks before events. These patients had not received cranial irradiation and had no evidence of CNS leukemia before or after these episodes. Ischemic changes on computerized tomographic scan or magnetic resonance imaging studies were documented in all three cases. Such changes are unusual manifestations of neurotoxicity in children after intrathecal therapy.