Cranioplasty with Autologous Bone Flaps Cryopreserved with Dimethylsulphoxide: Does Tissue Processing Matter.

OBJECTIVE: The aim of this article was to study the outcome of patients who underwent cranioplasty with cryopreserved autologous bone after decompressive craniectomy. METHODS: Data from 74 patients were retrospectively analyzed. They were divided into groups according to the storage time and the age at cranioplasty. To assess the predictive potential for complication, factors were related to successive stages (preoperative, craniectomy, tissue processing, cranioplasty, and postoperative). Cooling and warming rates applied on bone flap were calculated. The ability to inhibit microbial growth was determined exposing bone fragments to a panel of microorganisms. The concentration of antibiotics eluted from the bone was also determined. A bone explant culture method was used to detect living cells in the thawed cranial bone. RESULTS: Hydrocephalus was significantly more frequent in pediatric patients (26.7%) than in adults (5.1%). The overall rate of bone flap resorption was 21.6% (43.7% of which required reoperation). Surgical site infection after cranioplasty was detected in 6.8% of patients. There was no correlation between infection as a postoperative complication and previous microbiological-positive culture during processing. The cause of craniectomy did not influence the risk of bone flap contamination. Vancomycin was the only antibiotic detected in the supernatant where the bone was incubated. Outgrowth from bone explants was observed in 36.8% of thawed skulls. An early start of bone flap processing at the tissue bank had a positive effect on cell viability. CONCLUSIONS: The outcome after autologous cranioplasty is a multifactorial process, which is modulated by patient-related, surgery-related, and bone-related factors.

The storage of skull bone flaps for autologous cranioplasty: literature review.

The use of autologous bone flap for cranioplasty after decompressive craniectomy is a widely used strategy that allows alleviating health expenses. When the patient has recovered from the primary insult, the cranioplasty restores protection and cosmesis, recovering fluid dynamics and improving neurological status. During this time, the bone flap must be stored, but there is a lack of standardization of tissue banking practices for this aim. In this work, we have reviewed the literature on tissue processing and storage practices. Most of the published articles are focused from a strictly clinical and surgical point of view, paying less attention to issues related to tissue manipulation. When bone resorption is avoided and the risk of infection is controlled, the autograft represents the most efficient choice, with the lowest risk of complication. Otherwise, depending on the degree of involvement, the patient may have to undergo new surgery, assuming further risks and higher healthcare costs. Therefore, tissue banks must implement protocols to provide products with the highest possible clinical effectiveness, without compromising safety. With a centralised management of tissue banking practices there may be a more uniform approach, thus facilitating the standardization of procedures and guidelines.

Hydroxyethyl starch is an alternative washing solution for peripheral bloodstem cells products.

Cryopreservation of hematopoietic stem cells (HSC) involves slow rate cooling in the presence of a cryoprotectant (DMSO) to avoid the damaging effects of intracellular ice formation. The infusion of DMSO with the thawed product has been related to adverse events. Reduction of DMSO content by washing the HSCs after thawing has been suggested as a method to avoid infusion-related side-effects. Albumin-dextran washing methods have proved useful in thawing HSC products. Dextran40 shortages prompted us to search for suitable alternatives. We report the results of a comparative study of the use of hydroxyethyl starch (HES) as an alternative to dextran40 for washing thawed HSCs products. A total of 10 HSC bags cryopreserved with 10 % DMSO were used. We conducted a paired study; one of the bags was thawed and washed with our standard washing solution (Dextran 40) and the paired bag with HES solution with a final HES and Human Serum Albumin (HSA) concentration of 2.4 % and 4.2 % respectively. Each final product was tested immediately after washing (sample 0') and after 90 min (sample 90') for total nucleated cells (TNC) recovery, acridine orange viability, viable CD34+ enumeration, and clonogenicity. No significant difference was found for any of the cell counts, viability tests, cell recovery, or potency. We can state that the washing solution based on 2.4 % HES and 4.2 % HSA is equivalent to that used in our routine practice. Therefore, we could use the solution with HES, paying special attention to the renal function of the recipient.

Impact of clinical features, cytogenetics, genetic mutations, and methylation dynamics of CDKN2B and DLC-1 promoters on treatment response to azacitidine.

Azacitidine (AZA) is a DNA hypomethylation agent administered in myeloid neoplasms; however, there is still a lack of established predictors of response. We studied 113 patients with myelodysplastic syndromes (n = 85) or acute myeloid leukemia (n = 28) who received AZA to assess the predictive value on response of clinical features, cytogenetics, and molecular markers. Overall, 46 patients (41%) responded to AZA. Platelet doubling after the first AZA cycle was associated with a better response (68% vs. 32% responders, P = 0.041). Co-occurrence of chromosome 7 abnormalities and 17p deletion was associated with a worse response (P = 0.039). Pre-treatment genetic mutations were detected in 98 patients (87%) and methylation of CDKN2B and DLC-1 promoters were detected in 50 (44%) and 37 patients (33%), respectively. Patients with SF3B1 mutations showed a better response to AZA (68% vs. 35% responders, P = 0.008). In contrast, subjects with mutations in transcription factors (RUNX1, SETBP1, NPM1) showed a worse response (20% vs. 47% responders, P = 0.014). DLC-1 methylation pre-treatment was associated with poor clinical features and its reduction post-treatment resulted in a better response to AZA in MDS patients (P = 0.037). In conclusion, we have identified several predictors of response to AZA that could help select the best candidates for this treatment.

Oxidative imbalance in low/intermediate-1-risk myelodysplastic syndrome patients: The influence of iron overload.

OBJECTIVE: To assess the generation of reactive oxygen species (ROS) and the involvement of the main antioxidant pathways in low/intermediate-1-risk myelodysplastic syndromes (MDS) with iron overload (IOL). METHODS: We examined the levels of superoxide anion (O2-), hydrogen peroxide (H2O2), antioxidants (glutathione, GSH; superoxide dismutase, SOD; catalase, CAT; and glutathione peroxidase, GPx), mitochondrial membrane potential (ΔΨm), and by-products of oxidative damage (8-isoprostanes and 8-oxo-7,8-dihydro-2'-deoxyguanosine, 8-oxo-dG) in 42 MDS patients (28 without IOL at diagnosis, and 14 who developed IOL) and 20 healthy subjects. RESULTS: Patients with IOL showed higher O2- levels (39.4 MFI) than normal controls (22.7 MFI, p=0.0356) and patients at diagnosis (19.4 MFI, p=0.0049). Antioxidant systems, except SOD activity, exhibited significant changes in IOL patients with respect to controls (CAT: 7.1 vs 2.7nmol/ml/min, p=0.0023; GPx: 50.9 vs 76.4nmol/ml/min, p=0.0291; GSH: 50.2 vs 24.1 MFI, p=0.0060). Furthermore, mitochondrial dysfunction was only detected in IOL cases compared to controls (ΔΨm: 3.6 vs 6.4 MFI, p=0.0225). Finally, increased levels of 8-oxo-dG were detected in both groups of patients. CONCLUSION: Oxidative stress is an important but non-static phenomenon in MDS disease, whose status is influenced by, among other factors, the presence of injurious iron.

Amyloid generation and dysfunctional immunoproteasome activation with disease progression in animal model of familial Alzheimer's disease.

Double-transgenic amyloid precursor protein/presenilin 1 (APP/PS1) mice express a chimeric mouse/human APP bearing the Swedish mutation (Mo/HuAPP695swe) and a mutant human PS1-dE9 both causative of familial Alzheimer's disease (FAD). Transgenic mice show impaired memory and learning performance from the age of 6 months onwards. Double-transgenic APP/PS1 mice express altered APP and PS1 mRNAs and proteins, reduced ß-secretase 1 (BACE1) mRNA and normal BACE1 protein, all of which suggest a particular mechanism of amyloidogenesis when compared with sporadic AD. The first ß-amyloid plaques in APP/PS1 mice appear at 3 months, and they increase in number and distribution with disease progression in parallel with increased levels of brain soluble ß-amyloid 1-42 and 1-40, but also with reduced 1-42/1-40 ratio with age. Amyloid deposition in plaques is accompanied by altered mitochondria and increased oxidative damage, post-translational modifications and accumulation of altered proteins at the dystrophic neurites surrounding plaques. Degradation pathways are also modified with disease progression including activation of the immunoproteasome together with variable alterations of the different protease activities of the ubiquitin-proteasome system. Present observations show modifications in the production of ß-amyloid and activation and malfunction of the subcellular degradation pathways that have general implications in the pathogenesis of AD and more particularly in specificities of FAD amyloidogenesis.