Genotype and functional correlates of disease phenotype in deficiency of adenosine deaminase 2 (DADA2).

BACKGROUND: Deficiency of adenosine deaminase 2 (DADA2) is a syndrome with pleiotropic manifestations including vasculitis and hematologic compromise. A systematic definition of the relationship between adenosine deaminase 2 (ADA2) mutations and clinical phenotype remains unavailable. OBJECTIVE: We sought to test whether the impact of ADA2 mutations on enzyme function correlates with clinical presentation. METHODS: Patients with DADA2 with severe hematologic manifestations were compared with vasculitis-predominant patients. Enzymatic activity was assessed using expression constructs reflecting all 53 missense, nonsense, insertion, and deletion genotypes from 152 patients across the DADA2 spectrum. RESULTS: We identified patients with DADA2 presenting with pure red cell aplasia (n = 5) or bone marrow failure (BMF, n = 10) syndrome. Most patients did not exhibit features of vasculitis. Recurrent infection, hepatosplenomegaly, and gingivitis were common in patients with BMF, of whom half died from infection. Unlike patients with DADA2 with vasculitis, patients with pure red cell aplasia and BMF proved largely refractory to TNF inhibitors. ADA2 variants associated with vasculitis predominantly reflected missense mutations with at least 3% residual enzymatic activity. In contrast, pure red cell aplasia and BMF were associated with missense mutations with minimal residual enzyme activity, nonsense variants, and insertions/deletions resulting in complete loss of function. CONCLUSIONS: Functional interrogation of ADA2 mutations reveals an association of subtotal function loss with vasculitis, typically responsive to TNF blockade, whereas more extensive loss is observed in hematologic disease, which may be refractory to treatment. These findings establish a genotype-phenotype spectrum in DADA2.

Core-sheath micro/nano fiber membrane with antibacterial and osteogenic dual functions as biomimetic artificial periosteum for bone regeneration applications.

The traditional Chinese medicine icariin (ICA) and broad-spectrum antibacterial drug moxifloxacin hydrochloride (MOX) were introduced into a polycaprolactone core and gelatin shell, respectively, to develop osteogenic and antibacterial biomimetic periosteum by coaxial electrospinning. The physical properties, drug release, degradation, antibacterial property, in vitro and in vivo osteogenesis performances were investigated. Results demonstrated that stepwise and controlled drug release profiles were achieved based on the core-shell configuration and disparate degradation rate of PCL and gelatin. Only 20% ICA was released from this dual drug-loaded membrane after 1 month while the release of MOX was almost completed. Moreover, clear in vitro antibacterial effect and enhancement in osteogenic marker expressions including osteocalcin, type-I collagen expression, and calcium deposition were observed. Notably, the dual drug-loaded membrane displayed fascinating properties contributing to in vivo bone formation in terms of quality and quantity in a rabbit radius defect model.

Effective delivery of mitomycin-C and meloxicam by double-layer electrospun membranes for the prevention of epidural adhesions.

Epidural adhesion between the spinal dura and the surrounding fibrous tissue often occurs post-laminectomy, resulting in clinical symptoms such as nerve compression and severe pain. In this study, we report a drug-loaded double-layered electrospun nanofiber membrane to prevent the occurrence of epidural adhesion. The nanofibers in both layers are made of a mixture of polycaprolactone (PCL) and chitosan (CS) but at different weight ratios. The bottom layer contacting to the spinal dura is loaded with meloxicam (MX) to prevent inflammation. The top layer that contacts to the fibrous tissue is doped with mitomycin-C (MMC) to inhibit the synthesis of DNA and collagen. The two types of drugs are released from the double-layered membrane within about 12 days. Meanwhile, the membrane can inhibit fibroblasts proliferation in vitro while show no cytotoxicity. In a rabbit laminectomy model, the double-layered membrane can effectively prevent the epidural adhesion formation based on the adhesion scores, histological and biochemical evaluations. The combination release of MX and MMC can signally reduce the inflammation reaction and collagen I/III expression relative to the case with the membranes loaded with only either one type of the drugs. This approach offers new progresses in constructing dual drug delivery system and provides innovative barrier strategy in inhibiting epidural adhesion post-laminectomy.

Icariin-loaded electrospun PCL/gelatin sub-microfiber mat for preventing epidural adhesions after laminectomy.

BACKGROUND: Epidural adhesion is one of the major reasons attributed to failed back surgery syndrome after a successful laminectomy, and results in serious clinical complications which require management from physicians. Therefore, there is an urgent demand within the field to develop biodegradable anti-adhesion membranes for the prevention of post-operative adhesion. METHODS: In this study, icariin (ICA) was initially loaded into polycaprolactone (PCL)/gelatin fibers via electrospinning to fabricate nanofibrous membranes. The effects of the ICA content (0.5wt%, 2wt% and 5wt%) and the bioactivity of ICA in the nanofibrous membranes were investigated in vitro and in vivo. RESULTS: The nanofibrous membranes showed suitable pore size and good properties that were unaffected by ICA concentration. Moreover, the ICA-loaded membranes exhibited an originally rapid and subsequently gradual sustained ICA release profile that could significantly prevent fibroblast adhesion and proliferation. In vivo studies with rabbit laminectomy models demonstrated that the ICA-loaded membranes effectively reduced epidural adhesion by gross observation, histology, and biochemical evaluation. The anti-adhesion mechanism of ICA was found to be via suppression of the TGF-ß/Smad signaling proteins and down regulation of collage I/III and a-SMA expression for the first time. CONCLUSION: We believe that these ICA-loaded PCL/gelatin electrospun membranes provide a novel and promising strategy to resist adhesion formation following laminectomy in a clinical application.

Performance of microbial fuel cells with and without Nafion solution as cathode binding agent.

The performance of tubular microbial fuel cells (MFC) with and without Nafion solution as binding agent for the cathode catalyst preparation was investigated using different electrochemical techniques. The current output of both types of MFCs was monitored as a function of time using an external resistor. The current did not change much with time and was higher for the water cell (WC) than for the Nafion cell (NC). Cell voltage (U(c))-current (I) curves were recorded using a potentiodynamic technique. From the U(c)-I curves power concentration (P)-I and P-U(c) curves were constructed. The water cell (without Nafion) also achieved a higher maximum power output. The internal resistance that was determined from the cell voltage at which the power concentration reached its maximum value was higher for the NC than that for the WC, possibly due to the higher cathodic polarization resistance of the NC cell. The impedance for the cathodes decreased with exposure time for both cells due to increased porosity of the surface layers covering the cathode materials. No changes of the impedance were observed for the WC anode. For the NC anode the impedance spectra changed from a one-time constant system to a two-time constant system at the longer exposure time.