Inflammatory response to the administration of mesenchymal stem cells in an equine experimental model: effect of autologous, and single and repeat doses of pooled allogeneic cells in healthy joints.

BACKGROUND: Mesenchymal stem cells (MSCs) transplantation has become a promising therapeutic choice for musculoskeletal injuries. Joint-related disorders are highly prevalent in horses. Therefore, these animals are considered as suitable models for testing MSC-based therapies for these diseases. The aim of this study was to investigate the clinical and inflammatory responses to intra-articular single and repeat dose administration of autologous or of pooled allogeneic MSCs in healthy equine healthy joints. Six horses were intra-articularly injected with a single autologous dose of bone marrow derived MSCs (BM-MSCs) and two separate doses of allogeneic BM-MSCs pooled from several donors. All contralateral joints were injected with Lactated Ringer's Solution (LRS) as the control vehicle. Signs of synovitis and lameness were evaluated at days 0, 1, 2, 3, 5 and 10 after injection. Total protein (TP), white blood cell count (WBC) and neutrophil count (NC) in synovial fluid were also measured at the same time-points. RESULTS: A mild synovial effusion without associated lameness was observed after all BM-MSCs injections. The second allogeneic injection caused the lowest signs of synovitis. Local temperature slightly increased after all BM-MSCs treatments compared to the controls. TP, WBC and NC in synovial fluids also increased during days 1 to 5 after all BM-MSCs injections. Both, clinical and synovial parameters were progressively normalized and by day 10 post-inoculation appeared indistinguishable from controls. CONCLUSIONS: Intra-articular administration of an allogeneic pool of BM-MSCs represents a safe therapeutic strategy to enhance MSCs availability. Importantly, the absence of hypersensitivity response to the second allogeneic BM-MSCs injection validates the use of repeat dose treatments to potentiate the therapeutic benefit of these cells. These results notably contribute to the development of stem cell based therapies for equine and human joint diseases.

Role of serum holotranscobalamin (holoTC) in the diagnosis of patients with low serum cobalamin. Comparison with methylmalonic acid and homocysteine.

Plasma holotranscobalamin (holoTC) transports active cobalamin. Decreased levels of holoTC have been considered to be the earliest marker of cobalamin (Cbl) deficiency. In this work, holoTC was evaluated in low or borderline serum Cbl (LB12) and a concordance analysis was carried out with methylmalonic acid (MMA) and homocysteine (Hcy). Levels of Cbl, holoTC, MMA, and Hcy were investigated in a reference group in 106 patients with LB12 (≤200 pmol/l) and in 27 with folate deficiency (FOL). HoloTC levels were evaluated by an automated immunoassay (Active B12, Abbott Lab, Abbott Park, IL, USA). Lower levels of holoTC were observed in both LB12 and FOL groups (reference group vs LB12; p < 0.0001. Reference group vs FOL; p = 0.002). HoloTC levels were lower in LB12 than in FOL (p = 0.001). In LB12, concordance between Hcy and MMA was 82.1 % (chi-square test, p < 0.001; Kappa Index, 0.64, p < 0.0001). Concordance between Hcy and holoTC was 62 % (chi-square test, p = 0.006; Kappa index, 0.245, p = 0.006). Concordance between holoTC and MMA was 55.6 % (p = 0.233). Some cases with LB12 and elevated MMA did not show decreased holoTC. By contrast, MMA and Hcy were not increased in some patients with low holoTC and LB12. In conclusion, levels of holoTC were decreased in LB12 and FOL. In LB12 patients, holoTC concordance with MMA was poor. MMA/Hcy levels were not increased in a significant number of subjects with LB12 and low holoTC. This profile was found in iron deficiency. The significance of these changes remains to be clarified.

Management of iron deficiency in various clinical conditions and the role of intravenous iron: Recommendations of the Spanish Erythropathology Group of the Spanish Society of Haematology and Haemotherapy. / Manejo del déficit de hierro en distintas situaciones clínicas y papel del hierro intravenoso: recomendaciones del Grupo Español de Eritropatología de la SEHH.

Iron deficiency due to blood loss, absorption disorders and dietary deficiencies causes iron-deficiency anaemia, whose treatment seeks to eliminate the underlying cause and restore haemoglobin and iron deposits. Typically, the latter 2 of these objectives can be achieved through oral iron therapy. Intravenous iron administration (IIA) should be limited to those patients refractory or intolerant to oral preparations or who require rapid repletion. The indiscriminate use of IIA can increase morbidity and mortality due to iatrogenic overload. This fact, coupled with the growing popularity of IIA and the lack of reference guidelines in Spanish, led the Spanish Erythropathology Group of the Spanish Society of Haematology and Haemotherapy to develop this study, which presents the main recommendations on the optimal use of IIA in iron deficiency and attempts to constitute reference guidelines on good practices for the clinical management of these conditions.

Comparison of autologous bone marrow and adipose tissue derived mesenchymal stem cells, and platelet rich plasma, for treating surgically induced lesions of the equine superficial digital flexor tendon.

Several therapies have been investigated for equine tendinopathies, but satisfactory long term results have not been achieved consistently and a better understanding of the healing mechanism elicited by regenerative therapies is needed. The aim of this study was to assess the separate effects of autologous bone marrow (BM) and adipose tissue (AT) derived mesenchymal stem cells (MSCs), and platelet rich plasma (PRP), for treating lesions induced in the superficial digital flexor tendon (SDFT) of horses. Lesions were created surgically in both SDFTs of the forelimbs of 12 horses and were treated with BM-MSCs (six tendons), AT-MSCs (six tendons) or PRP (six tendons). The remaining six tendons received lactated Ringer's solution as control. Serial ultrasound assessment was performed prior to treatment and at 2, 6, 10, 20 and 45 weeks post-treatment. At 45 weeks, histopathology and gene expression analyses were performed. At week 6, the ultrasound echogenicity score in tendons treated with BM-MSCs suggested earlier improvement, whilst all treatment groups reached the same level at week 10, which was superior to the control group. Collagen orientation scores on histological examination suggested a better outcome in treated tendons. Gene expression was indicative of better tissue regeneration after all treatments, especially for BM-MSCs, as suggested by upregulation of collagen type I, decorin, tenascin and matrix metalloproteinase III mRNA. Considering all findings, a clear beneficial effect was elicited by all treatments compared with the control group. Although differences between treatments were relatively small, BM-MSCs resulted in a better outcome than PRP and AT-MSCs.

Effect of inflammatory environment on equine bone marrow derived mesenchymal stem cells immunogenicity and immunomodulatory properties.

Mesenchymal stem cells (MSCs) are being investigated for the treatment of equine joint diseases because of their regenerative potential. Recently, the focus mainly has addressed to their immunomodulatory capacities. Inflammation plays a central role in joint pathologies, since the release of proinflammatory mediators to the synovial fluid (SF) leads to the activation of enzymatic degradation of the cartilage. MSCs can modulate the local immune environment through direct or paracrine interaction with immune cells, suppressing their proliferation and re-addressing their functions. Proinflammatory molecules can induce MSC immunoregulatory potential, but they could also increase the expression of immunogenic molecules. Studying the effect of inflammatory environment on MSC immunomodulation and immunogenicity profiles is mandatory to improve cellular therapies. The aim of this study was to analyse the response of equine bone marrow MSCs (eBM-MSCs) to three inflammatory conditions. Equine BM-MSCs from three animals were exposed to: (a) 20% allogeneic inflammatory SF (SF); (b) 50 ng/ml of TNFα and IFNγ (CK50) and (c) 20 ng/ml of TNFα and IFNγ (CK20). After 72 h of exposure, expression of immunogenic and immunomodulation-related molecules, including cell-to-cell contact and paracrine signalling molecules, were analysed by RT-qPCR and flow cytometry. The gene expression of adhesion molecules was upregulated whereas MSC migration-related genes were downregulated by all inflammatory conditions tested. CK culture conditions significantly upregulated the expression of COX-2, iNOS, IDO and IL-6. MHC-I gene expression was upregulated by all conditions, whereas MHC-II was upregulated only after CK priming. The expression of CD40 did not significantly change, whereas the ligand, CD40L, was downregulated in CK conditions. Flow cytometry showed an increase in the percentage of positive cells and mean fluorescence intensity (MFI) of the MHC-I and MHC-II molecules at CK50 conditions, supporting the gene expression results. These outcomes reinforce the change of the immunophenotype of the eBM-MSCs according to the surrounding conditions. Inflammatory synovial environment did not lead to significant changes, so the environment found by eBM-MSCs when they are intraarticular administered may not be enough to activate their immunomodulatory potential. CK priming at tested doses enhances the immunoregulatory profile of eBM-MSCs, which may promote a therapeutic benefit. Even if CK priming induced an upregulation of MHC expression, costimulatory molecule expression however was not upregulated, suggesting that immunogenicity might not be increased. This study provides a better understanding about the behaviour of eBM-MSCs inside the inflamed joint and constitutes a first step to improve MSC-based therapies for equine joint diseases.

Vitamin B12 and folate levels increase during treatment of iron deficiency anaemia in young adult woman.

INTRODUCTION: The relationship between iron deficiency and vitamin B12 and folate was recognized several decades ago. Combined deficiency is important in clinical practice owing to its relationship with malabsorption syndromes. By contrast, iron deficiency and low levels of serum vitamin B12 with normal metabolic markers were often found mostly in young adults. In this work, vitamin B12/folate changes were investigated during treatment of iron deficiency anaemia (IDA) with pharmacological iron in young adult women. METHODS: A cohort of 35 young adult women with IDA was treated with oral iron. An haematological response was obtained in 97.2% at 4-month follow-up. Changes in serum vitamin B12, serum folate and other biochemical parameters were monitored. RESULTS: Treatment with iron increased significantly serum folate and vitamin B12 from baseline. This increase was also observed in vitamin B12 levels ≤200 pmol/L (six patients, 17.1%), in whom serum vitamin B12 was above 200 pmol/L at the end of the study in all cases. Other biochemical parameters also changed. Significant increases were seen for glucose (P = 0.012), uric acid (P < 0.001), total cholesterol (P = 0.023), HDL cholesterol (P = 0.026) and bilirubin (P < 0.001). Urea decreased significantly (P = 0.036). CONCLUSIONS: Data from our work suggest that iron deficiency could affect many metabolic pathways, including vitamin B12, folate and lipids. These changes normalize after iron therapy, even in women with baseline low levels of serum vitamin B12. Healthcare practitioners should be aware of these changes in IDA management. The mechanisms controlling these changes remain to be explained, but they are probably related to the control of iron homeostasis (iron deficiency mediated stimuli).

Cobalamin deficiency in patients infected with the human immunodeficiency virus.

Serum vitamin B12 levels are often low in human immunodeficiency virus (HIV)-infected patients. However, only a few patients appear to have actual vitamin B12 deficiency. A low red cell folate level accompanying the low vitamin B12 level makes the presence of vitamin B12 deficiency more likely. Our experience suggests that a low red cell folate level always indicates deficiency, but does not differentiate between vitamin B12 and folate deficiency. The deoxyuridine suppression test and the assay of serum or plasma total homocysteine and/or of methylmalonic acid levels can also be useful in the identification of patients with true vitamin B12 deficiency. HIV-positive patients frequently have absorption disorders, including vitamin B12 malabsorption. However, the correlation between vitamin B12 malabsorption and serum vitamin B12 and plasma homocysteine levels is poor. Abnormalities in vitamin B12-binding proteins, which are often found in HIV-positive patients, may explain many cases of low vitamin B12 levels. Current evidence suggests that low vitamin B12 levels are more common as the HIV disease progresses. The results of vitamin B12 treatment have been disappointing thus far, including the prevention of toxicity induced by azidothymidine. The possible role of vitamin B12 treatment in the long-term survival of HIV-infected patients is at present unknown. However, it is important to identify those patients who have real vitamin B12 deficiency to treat or prevent their hematologic and/or neurological symptoms.

Evaluation of immunoassays for the measurement of soluble transferrin receptor as an indirect biomarker of recombinant human erythropoietin misuse in sport.

Soluble transferrin receptor (sTfR) has been proposed as an indirect biomarker of the misuse of recombinant human erythropoietin in sport. An extended validation of four commercially available immunoassays for its measurement in serum is presented. Two ELISA techniques (ELISA1: Orion Diagnostica; ELISA2: R&D Systems), an immunoturbidimetric technique (Turbid: Roche Diagnostics), and a nephelometric technique (Nephel: Dade Behring) were investigated. Intra-laboratory precision better than 3% and correct accuracies were obtained for the Turbid and Nephel techniques using autoanalysers. Slightly worse precision (but always better than 11%) and correct accuracies were also obtained in almost all cases for the two ELISA techniques. Inter-laboratory results showed higher concordances for the ELISA procedures (intraclass correlation coefficients of 0.848 for ELISA1 and 0.973 for ELISA2 which was clearly better). Inter-technique correlations were good for the four techniques with lower dispersions found for the techniques using autoanalysers, i.e. Turbid and Nephel. While Turbid and ELISA1 results (expressed in mg/l) were comparable, results obtained with Nephel were approximately 2.7 times lower. The relationship between those three techniques was maintained when compared with ELISA2, which uses different units (nmol/l). We conclude that ELISA2 and Nephel in our hands were the most suitable techniques in terms of sensitivity, precision and accuracy, and adequacy of the calibration curve for the measurement of sTfR in real serum samples. Discrepancies observed in the results obtained with the different sTfR techniques showed that different reference standards were used and harmonization is recommended in order to obtain comparable results.

Frequent severe liver iron overload after stem cell transplantation and its possible association with invasive aspergillosis.

Iron overload is associated with free radical generation and tissue damage. Our main objective was to ascertain the frequency and severity of iron overload in a group of 59 patients who died after conventional-intensity autologous (n=24) or allogeneic (n=35) haematopoietic stem cell transplantation (HSCT). A second objective was to investigate associations between liver-iron concentration and causes of transplant-related mortality. The median age was 41 years (range, 19-66), 41 were males and 18 females. In total, 26 patients had acute leukaemia or MDS, 10 CML, 17 lymphoma, four myeloma and two aplastic anaemia. The median hepatic iron concentration (HIC) was 138 micromol/g dry weight (7.7 mg/g; range 31-631 micromol/g). In total, 4/32 (12%) patients with HIC <150 micromol/g and 10/27 (37%) with hepatic iron > or =150 micromol/g showed invasive aspergillosis at autopsy (P=0.035). This was significant in multivariate analysis (RR 9.0; 95% CI 1.6-50.3, P=0.012). In conclusion, severe iron overload is frequent in patients who die following HSCT and is associated with invasive aspergillosis.

Changes in reticulocyte fractions during peripheral stem cell harvesting: role in monitoring stem cell collection.

We prospectively evaluated the changes in immature reticulocyte fractions during peripheral blood stem cell mobilization to determine any possible relationship with mobilization of stem cells into the peripheral blood. Circulating neutrophils, immature reticulocyte fractions (% of HFR + MFR) (HMFR) (measured by flow cytometry), circulating CD34+ cells (measured by flow cytometry) and CFU-GM (measured by semisolid media assay in the apheresis fluid) were closely monitored following priming with chemotherapy and colony-stimulating factors in 15 patients with hematological or solid tumors (group I). Day 0 was defined as the day on which the neutrophil count fell below 0.5 x 10(9)/l. In a second group of nine patients (group II) reticulocyte fractions and CD34+ cells were measured directly on the days on which they were predicted to increase using the data from group I. Reticulocyte counts and HMFR were also monitored in 18 patients who were mobilized with G-CSF alone. In group I, a significant rise in HMFR and CD34+ cells occurred on days 2, 4 and 6, and a linear correlation between HMFR on day 2 and CD34+ cells on day 4 was demonstrated (P = 0.0068, r = 0.74). In group II similar patterns of recovery were found. During mobilization with G-CSF alone HMFR significantly increased on days 2, 4 and 6 of treatment with respect to baseline values, and a multiplicative relationship between the increase of HMFR and neutrophils was observed (r = 0.707, P < 0.00001). Unfortunately, patients who did not mobilize CD34+ cells (one in groups I and II and three in the G-CSF group) showed similar HMFR kinetics to those who mobilized CD34+ cells. An increase in immature reticulocyte fractions precedes the presence of circulating CD34+ cells by about 2 days in patients mobilized with chemotherapy and growth factors, and it could thus serve as an indirect surrogate marker for monitoring the timing of stem cell harvesting. An unexpected increase of HMFR during treatment with G-CSF alone was found, indicating an effect of this factor on erythropoiesis in vivo.

Iron overload might increase transplant-related mortality in haematopoietic stem cell transplantation.

Iron overload (IO) is associated with free radical generation and tissue damage. Our main objective was to ascertain if very high levels (VHL) of ferritin (>/=3000 microg/l) and transferrin saturation (TS) >/=100% during conditioning had an impact on overall survival (OS) and transplant-related mortality (TRM) after a haematopoietic stem cell transplantation (HSCT). Levels of ferritin and TS were measured at days -7 and -4, respectively, in 25 patients who underwent HSCT after CY/TBI. The group consisted of 20 men and five women with a median age of 40 years. Fifteen patients were autotransplanted and 10 allotransplanted. Nine of them had a diagnosis of AL, six of CML and 10 of lymphoma. Thirteen of them were in early and 12 in advanced status of disease. VHL of ferritin and TS >/=100% were associated with a decreased OS (P = 0.001 and P = 0.006, respectively) and an increased TRM (P = 0.003 and P = 0.004, respectively) in univariate survival analysis. Both variables remained significant at multivariate analysis for OS (P = 0.03 and 0.02, respectively) and TS was an independent factor for TRM (P = 0.01). Ferritin was very close to achieving statistical significance for TRM (P = 0.06) in multivariate analysis. In conclusion, VHL of ferritin and TS >/=100% at conditioning are associated with an increase in toxic deaths after transplant.

Measurement of liver iron overload by magnetic induction using a planar gradiometer: preliminary human results.

The measurement of hepatic iron overload is of particular interest in cases of hereditary hemochromatosis or in patients subject to periodic blood transfusion. The measurement of plasma ferritin provides an indirect estimate but the usefulness of this method is limited by many common clinical conditions (inflammation, infection, etc). Liver biopsy provides the most quantitative direct measurement of iron content in the liver but the risk of the procedure limits its acceptability. This work studies the feasibility of a magnetic induction (MI) low-cost system to measure liver iron overload. The excitation magnetic field (B0, frequency: 28 kHz) was produced by a coil, the perturbation produced by the object (deltaB) was detected using a planar gradiometer. We measured ten patients and seven volunteers in supine and prone positions. Each subject was moved in a plane parallel to the gradiometer several times to estimate measurement repeatability. The real and imaginary parts of deltaB/B0 were measured. Plastic tanks filled with water, saline and ferric solutions were measured for calibration purposes. We used a finite element model to evaluate the experimental results. To estimate the iron content we used the ratio between the maximum values for real and imaginary parts of deltaB/B0 and the area formed by the Nyquist plot divided by the maximum imaginary part. Measurements in humans showed that the contribution of the permittivity is stronger than the contribution of the permeability produced by iron stores in the liver. Defined iron estimators show a limited correlation with expected iron content in patients (R < or = 0.56). A more precise control of geometry and position of the subjects and measurements at multiple frequencies would improve the method.

[Atypical familial microcytosis: a familial and genetic study]. / Microcitosis familiares atípicas: estudio familiar y genético.

The characteristics of familiar atypical microcytosis studied during one year were evaluated. Out of 149 patients with microcytosis in whom iron deficiency was ruled out, a heterogenous beta-thalassemia was diagnosed in 72 cases, a heterozygous delta beta-thalassemia in 16 cases and a hemoglobinopathy in 3 cases. The microcytosis was related to an inflammatory anemia in 12 cases and to an hemopathy in 9 cases. An atypical microcytosis was detected in 37 patients. A familiar and molecular analysis was carried out to detect alpha-thalassemia in cases with atypical microcytosis. It was possible to complete the familiar and molecular analysis in 35 out of 37 cases, and an alpha-thalassemia was observed in 31 patients. Most cases proved to be heterozygous or homozygous-alpha 3.7-thalassemia. No patient with heterozygous alpha zero-thalassemia was found. Most cases of familiar atypical microcytosis in our country are due to -alpha 3.7-thalassemia. Bearing these findings in mind, this analysis should only be used in situations where a problem of prenatal diagnosis is present. Moreover, systematic molecular analysis of familiar atypical microcytosis could be justified if the MCV is lower than 75 fl.

[Hematologic deficiencies in patients with recurrent oral aphthae]. / Estudio de los déficit hematológicos en los enfermos afectados de aftas orales recidivantes.

BACKGROUND: The prevalence of iron, folic acid and vitamin B12 deficiencies and their role in the development of recurrent oral ulcerations is not well known. The aim of this study was to determine the prevalence of these deficiencies in our patients. PATIENTS AND METHODS: Iron, folic acid and vitamin B12 levels were studied in 80 patients with recurrent oral ulcerations (ROU) and the results were compared with a control group of 29 patients with different oral diseases. RESULTS: In the recurrent oral ulcers patients, deficiencies were detected in 21/80 patients (26.2%). In 18 cases they were pure: iron (4), folic acid (10) and vitamin B12 (4). In 3 patients, combined deficiencies were detected, being secondary to pernicious anaemia in two patients. In the control group, deficiencies were observed in 4/29 cases (13.7%). In three cases they were isolated (one case suffered from ferropenic anaemia and two patients of pernicious anaemia). CONCLUSIONS: Patients with recurrent oral ulcerations have more frequently iron, folic acid and vitamin B12 deficiencies than those with other diseases of oral mucosa. However, there were not significant differences when the frequency of deficiency of each one of such elements were taken into account separately.

[Influence of chronic renal failure and of its treatment on serum erythropoietin]. / Influencia de la insuficiencia renal crónica y de su tratamiento en la eritropoyetina sérica.

BACKGROUND: In order to know the influence of dialysis treatment in erythropoietin production, serum erythropoietin (Ep) has been studied in patients with anemia due to chronic renal failure (CRF). METHODS: Thirty six of them in hemodialysis (HD), 10 in continuous ambulatory peritoneal dialysis (CAPD) and 18 in predialysis stage (PD) and their results were compared to two control groups, including 72 healthy controls (HC) and the second one 89 iron deficiency anemia patients (ID). RESULTS: Patients had lower Hb and Ep levels than the other groups. Although Ep was higher in CAPD and PD. Ep levels were similar to HC values, and lower than ID levels. It could be demonstrated any correlation between Hb and Ep in CRF patients, however a negative exponential correlation was demonstrated in ID patients between Hb and Ep (r = -0.83; p less than 0.00001). In summary, Ep is higher in CAPD and in PD than in HD, but the levels are lower than they should be expected. CONCLUSIONS: These data confirm an Ep production failure in most of IRC patients and it seems likely that Ep treatment could be effective to treat the anemia of CRF.

[Molecular study of red cell pyruvate kinase deficiency in 15 patients with chronic hemolytic anemia. Group of Erythropathology of Hematology and hemotherapy Association of Spain (HHAS)]. / Estudio molecular del déficit de piruvatocinasa eritrocitaria en 15 pacientes con anemia hemolítica crónica. Grupo de Eritropatología de la Asociación Española de Hematología y Hemoterapia (AEHH).

BACKGROUND: Identification of RBC pyruvate-kinase (PK) gene mutations by polymerase chain reaction (PCR) and single strand conformation polymorphism (SSCP) followed by PK gene sequencing in positive cases has been assessed and the results obtained with a preliminary study of 15 unrelated patients of Spanish origin are presented. PATIENTS AND METHODS: Patients have been classified into two different groups: group 1, propositus (15 cases), and group 2, relatives of the patients included in group 1 (10 males and 5 females). In group 1, a PCR was followed by SSCP and sequencing, and in group 2, the PCR was followed by digestion with specific restriction endonucleases (PCR-ER). RESULTS: Group 1: from 15 patients included in the study 2 were identified as homozygous, 4 as heterozygous and 9 as compound heterozygous. In this group, were identify 26 affected alleles with 11 different mutations: T1456 10 alleles (38.6%), T721 3 alleles (11.6%), A1010, C514, C1015 and T1223 2 alleles (7.7%), and C1070, A1291, T1508, A1595 y T1675 one allele. Relatives from 8 out of 15 patients from group 1 showed the following pattern: homozygous (one case), heterozygous (10 cases), compound heterozygous (2 cases) and normal (2 cases). CONCLUSIONS: SSCP procedure followed by direct gene sequencing in positive cases is fast and simple enough to allow the identification of PK deficient variants, avoiding the need of biochemical characterisation of semipurified deficient enzyme, which is more cumbersome and time consuming. In addition, the PCR-ER method is a very useful tool for screening of the most frequent molecular variants, as well as, for the detection of the carrier condition of this enzymopathy (family studies).

Immune complexes and persistent high levels of serum vitamin B12.

INTRODUCTION: Patients with persistent high levels of serum vitamin B12 were often referred to Hematology departments. In this study, characteristic of patients with serum vitamin B12 levels higher than 2500 pmol/L (high B12) were studied. METHODS: Prevalence of high B12 was evaluated during a 10-month period. Samples with high B12 were incubated with polyethylene glycol (PEG) and a new measurement of vitamin B12 was carried out using the supernatant. As a pilot study, 26 frozen samples with high B12 were evaluated for changes in vitamin B12 after PEG. Moreover, a prospective study was carried out during three consecutive months. Size exclusion chromatography was employed to demonstrate the presence of immune complexes (ICs) with plasma vitamin B12-binding proteins in some serum samples with high B12. RESULTS: Prevalence of high B12 was 1.3%. Results from 26 frozen samples and from a prospective study (28 cases) showed that undergoing vitamin B12 treatment was the main cause of high B12. However, ICs were detected in 10 frozen samples and in seven cases (25%) of the prospective study, respectively. Serum vitamin B12 decreased to normal values after precipitation with PEG, and size exclusion chromatography confirmed ICs. An association with autoimmune or hematological disorders was observed. CONCLUSIONS: In patients with repeatedly high B12 levels, ICs were detected in approximately 25% of samples. Precipitation with PEG is an easy method to confirm the presence of ICs and to evaluate serum vitamin B12 levels in these patients.

Comparative study of equine bone marrow and adipose tissue-derived mesenchymal stromal cells.

REASONS FOR PERFORMING STUDY: Mesenchymal stromal cells (MSCs) represent an attractive source for regenerative medicine. However, prior to their application, fundamental questions regarding molecular characterisation, growth and differentiation of MSCs must be resolved. OBJECTIVES: To compare and better understand the behaviour of equine MSCs obtained from bone marrow (BM) and adipose tissue (AT) in culture. METHODS: Five horses were included in this study. Proliferation rate was measured using MTT assay and cell viability; apoptosis, necrosis and late apoptosis and necrosis were evaluated by flow cytometry. The mRNA expression levels of 7 surface marker genes were quantified using RT-qPCR and CD90 was also analysed by flow cytometry. Differentiation was evaluated using specific staining, measurement of alkaline phosphatase activity and analysis of the mRNA expression. RESULTS: High interindividual differences were observed in proliferation in both cell types, particularly during the final days. Statistically significant differences in viability and early apoptosis of cultured AT- and BM-MSCs were found. The highest values of early apoptosis were observed during the first days of culture, while the highest percentage of necrosis and late apoptosis and lowest viability was observed in the last days. Surface marker expression pattern observed is in accordance to other studies in horse and other species. Osteogenic differentiation was evident after 7 days, with an increasing of ALP activity and mRNA expression of osteogenic markers. Adipogenic differentiation was achieved in BM-MSCs from 2 donors with one of the 16 media tested. Chondrogenic differentiation was also observed. CONCLUSIONS: Proliferation ability is different in AT-MSCs and BM-MSCs. Differences in viability and early apoptosis were observed between both sources and CD34 was only found in AT-MSCs. Differences in their osteogenic and adipogenic potential were detected by staining and quantification of specific tissue markers. POTENTIAL RELEVANCE: To provide data to better understand AT-MSCs and BM-MSCs behaviour in vitro.

Darbepoetin alfa for anemia in patients with low or intermediate-1 risk myelodysplastic syndromes and positive predictive factors of response.

BACKGROUND: Current guidelines support the use of erythropoiesis-stimulating agents for the treatment of anemia associated with low-risk myelodysplastic syndromes (MDS). DESIGN AND METHODS: Single-arm, open-label, multi-center, phase 2 trial that evaluated the efficacy and safety of darbepoetin alfa (DA) in patients with low or intermediate-risk MDS, hemoglobin <100 g/L, erythropoietin (EPO) levels <500 IU/L and transfusion requirements <2 units/month over the preceding 2 months. Erythroid response (major [MaR] or minor [MiR]) and fatigue (Functional Assessment of Cancer Therapy-Fatigue [FACT-F]) were evaluated at 8, 16 and 24 weeks. DA was initiated at 300 µg weekly. For patients who did not achieve MaR by 8 weeks, filgrastim 300 µg weekly was added. CLINICAL TRIAL REGISTRATION: clinicaltrials.gov identifier: NCT01039350. RESULTS: Forty-four patients (72.7% transfusion independent) were included. Median age was 76.0 years (range 41.3-92.4), 54.5% were male, and 90.9% presented ECOG Status (0-1). Eighteen patients received filgrastim. An erythroid response was achieved by 31 of 44 patients (70.5%) at week 8 (47.7% MaR, 22.7% MiR), 31 of 44 patients (70.5%) at week 16 (61.4% MaR, 9.1% MiR), and 32 of 44 patients (72.7%) at week 24 (61.3% MaR, 11.4% MiR). Mean (95% CI) change in FACT-F at week 24 was 3.61 (0.72 to 6.51). Baseline EPO levels <100 IU/L were a predictive factor of response. DA was well tolerated. Four mild (two iron deficiencies, flu syndrome and headache) and one fatal (thromboembolic event) adverse events were considered related to darbepoetin alfa. CONCLUSIONS: A fixed dose of 300 µg of darbepoetin alfa weekly (with or without filgrastim) seems to be an effective and safe treatment for anemic patients with low or intermediate-risk MDS, low transfusion burden and EPO levels <500 IU/L. Results may not be extrapolable to unselected MDS patients.