PTPs inhibitor

Risk factors for the development of inhibitors in previously untreated patients (PUPs) have been reported; this is not the case in previously treated patients (PTPs) owing to fewer studies. Risk factors may differ for the development of PTP versus PUP inhibitors. We aimed to identify risk factors for PTP inhibitor development.

Participants were patients at a hemophilia treatment center in Korea with current or past history of factor VIII or factor IX alloantibodies. Observed inhibitors were classified as PUP or PTP inhibitors based on the cumulative number of exposure days. We compared the type and severity of hemophilia, mutation type, and family history of inhibitor between PUPs and PTPs. Events within 3 months before the first inhibitor detection, such as change of the factor concentrate used, short-term high exposure or continuous infusion of factor concentrate, history of surgery, infection, diagnosis of cancer, use of immunosuppressive or immunomodulator agents, and vaccination were compared between PUPs and PTPs.

We observed 5 PUP inhibitors and 5 PTP inhibitors in 115 patients with hemophilia A. Events that might be related to the development of inhibitors within 3 months prior to the first inhibitor detection were observed in all 5 PTPs. On the contrary, no such events were observed in any PUPs. The observed events included a change in the factor concentrate used, subsequent chemotherapy, and short-term high exposure to factor concentrates for controlling hemorrhage and surgeries.

Our results suggest a greater role of nongenetic factors in PTP inhibitor development.

Lateral habenula nucleus (LHb) has recently been noted for its role in stress-induced depressive disorder. Yet little is known about the mechanisms by which external stimuli or depression induces pathological alteration in the LHb.

Chronic unpredictable mild stress (CUMS) was employed to model depressive-like behaviors in adult rats. We examined expressions of DNA methyltransferases (Dnmts) mRNA and protein and global DNA methylation levels in LHb of CUMS-induced depressive rats. Then 5-aza-2'-deoxycytidine (5-aza), a Dnmts inhibitor, was infused into the LHb of native rats to test the effects of hypomethylation in the LHb. The gene expressions in the LHb and the levels of 5-HT and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in dorsal raphe nucleus (DRN) were examined in 5-aza infusion rats by quantitative real-time PCR and high performance liquid chromatography, respectively.

Rats were exposed to CUMS for 21 days and depressive-like behaviors were induced as expected. We observed significant decrease in mRNA and protein expressions of Dnmt1 and DNA hypomethylation in LHb of depressive rats. These phenomenon suggests that CUMS-induced depressive-like behaviors are related with DNA hypomethylation in the LHb. Local 5-aza infusion into LHb of native rat resulted in global DNA hypomethylation in the LHb and induced depressive-like behaviors which are featured with lack of interest and investment in the environment, behavioral despair and anhedonia. Moreover, DNA hypomethylation in the LHb increased transcription of β calcium/calmodulin dependent protein kinase II and glutamate receptor 1 in the LHb and attenuated the levels of 5-HT and 5-HIAA in the DRN. Our data suggested that alteration of DNA methylation in the LHb may control 5-HT neuronal activity in the DRN to regulate emotional state.

DNA hypomethylation in the LHb is involved in the development of depressive-like behavior and suitable methylation state contributes to the emotional stabilization.