The Coronavirus Pandemic (SARS-CoV-2): New Problems Demand New Solutions, the Alternative of Mesenchymal (Stem) Stromal Cells

Mesenchymal (stem) stromal cells (MSC) can be a therapeutic alternative for COVID-19 considering their anti-inflammatory, regenerative, angiogenic, and even antimicrobial capacity. Preliminary data point to therapeutic interest of MSC for patients with COVID-19, and their effect seems based on the MSC's ability to curb the cytokine storm caused by COVID-19. In fact, promising clinical studies using MSC to treat COVID-19, are currently underway. For this reason, now is the time to firmly consider new approaches to MSC research that addresses key issues, like selecting the most optimal type of MSC for each indication, assuming the heterogeneity of the donor-dependent MSC and the biological niche where MSC are located.

The ESCRT-Related ATPase Vps4 Is Modulated by Interferon during Herpes Simplex Virus 1 Infection

Interferons (IFNs) and autophagy are critical neuronal defenses against viral infection. IFNs alter neuronal autophagy by promoting the accumulation of IFN-dependent LC3-decorated autophagic structures, termed LC3 clusters. Here, we analyzed LC3 clusters in sensory ganglia following herpes simplex virus 1 (HSV-1) infection. In the vicinity of acutely infected neurons, antigen-negative neurons contained structures resembling accumulated autophagosomes and autolysosomes that culminated in LC3 clusters. This accumulation reflects a delayed completion of autophagy. The endosomal sorting complexes required for transport (ESCRT) machinery participates in autophagosome closure and is also required for HSV-1 replication. In this study, our results showed that HSV-1 infection in vivo and in primary neurons caused a decrease in Vps4 (a key ESCRT pathway ATPase) RNA and protein with concomitant Stat1 activation and LC3 cluster induction. We also observed that IFNs were sufficient to decrease RNA and protein levels of Vps4 in primary neurons and in other cell types. The accumulation of ubiquitin was also observed at the LC3 cluster sites. Together, our results show that IFNs modulate the ESCRT machinery in neurons in response to HSV-1 infections.IMPORTANCE Neurons rely on IFNs and autophagy as major defenses against viral infections, and HSV must overcome such defenses in order to replicate. In addition to controlling host immunity, HSV must also control host membranes in order to complete its life cycle. HSV uses the host ESCRT membrane scission machinery for viral production and transport. Here we present evidence of a new IFN-dependent mechanism used by the host to prevent ESCRT subversion by HSV. This activity also impacts the dynamics of autophagy, possibly explaining the presence of recently described LC3 clusters in the HSV-infected nervous system. The induced accumulations of ubiquitin observed in these LC3 clusters resembled those observed in certain neurodegenerative diseases, suggesting possible mechanistic parallels between these conditions.

Growth differentiation factor 11 (GDF11) - a promising anti-ageing factor - is highly concentrated in platelets

Recent research suggests that growth differentiation factor 11 (GDF11) could reverse age-related diseases and that its blood concentration decreases with age. This poses plasma from young donors as a therapeutic GDF11 source to treat age-related diseases. In addition, the tissue source of circulating GDF11 remains unknown. We analysed GDF11 levels in paired samples of serum, plasma and platelet lysate (PL) from 23 volunteers. Plasma and PL were collected by plateletpheresis. Here, we show that GDF11 is highly concentrated in platelets and that the circulating levels reported in previous studies could be biased as a result of serum sample manipulation.

Severe infections after single umbilical cord blood transplantation in adults with or without the co-infusion of CD34+ cells from a third-party donor: results of a multicenter study from the Grupo Español de Trasplante Hematopoyético (GETH)

BACKGROUND

Umbilical cord blood transplantation (CBT) is an established alternative source of stem cells in the setting of unrelated transplantation. When compared with other sources, single-unit CBT (sCBT) is associated with a delayed hematologic recovery, which may lead to a higher infection-related mortality (IRM). Co-infusion with the sCBT of CD34+ peripheral blood stem cells from a third-party donor (TPD) (sCBT + TPDCD34+) has been shown to markedly accelerate leukocyte recovery, potentially reducing the IRM. However, to our knowledge, no comparative studies have focused on severe infections and IRM with these 2 sCBT strategies.

METHODS

A total of 148 consecutive sCBT (2000-2010, median follow-up 4.5 years) were included in a multicenter retrospective study to analyze the incidence and risk factors of IRM and severe viral and invasive fungal infections (IFIs). Neutrophil engraftment occurred in 90% of sCBT (n = 77) and 94% sCBT + TPDCD34+ (n = 71) recipients at a median of 23 and 12 days post transplantation, respectively (P < 0.01).

RESULTS

The 4-year IRM was 24% and 20%, respectively (P = 0.7), with no differences at day +30 (5% and 4%, respectively) and day +100 (10% and 8%, respectively). In multivariate analysis early status of the underlying malignancy, cytomegalovirus (CMV)-seronegative recipient and high CD34+ cell content in the cord blood unit before cryostorage (≥1.4 × 10(5) /kg) were protective of IRM. Among the causes of IRM, bacterial infections and IFIs were more common in sCBT (15% vs. 4%), while CMV disease and parasitic infections were more common in the sCBT + TPDCD34+ cohort (5% vs. 16%).

CONCLUSION

These data show that sCBT supported with TPDCD34(+) cells results in much shorter periods of post-transplant leukopenia, but the short- and long-term rates of IRM were comparable to those of sCBT, presumably because immune recovery is equally delayed in both graft types.

[Umbilical cord blood cell transplantation from an unrelated donor: dual transplantation]

Our team conducted an original procedure of hematopoietic transplantation of umbilical cord blood (UCB) from an unrelated donor. The procedure consists of co-infusing hematopoietic stem cells selected from the blood of a third-party donor; it is conceived as a tool to shorten the engraftment period without preventing the engraftment of the UCB, even when using units with relatively low cell content and a low HLA compatibility. Between 1999 and 2008 we performed 64 transplantations in 60 adult patients (35 men and 25 women) with a median age of 34 years (range: 76-60) and a median weight of 70 kg (range: 43-95), all of whom were diagnosed with a high risk hematologic neoplasm (leukemia in most cases). Fludarabine, cyclophosphamide, ATG, and whole body irradiation or busulfan were used as conditioners. UCB was infused at medians of 2.4 x 107 CNT/kg (range: 1.14-4.30 x 107), 0.11 x 106 CD34+/kg (range: 0.035-0.37 x 106). Then, hematopoietic stem cells selected from the third-party donor were infused (2.43 x 106/kg [range: 1.05-3.34 x 106], with 0.3 x 104 CD3+/kg [range: 0.05-1.56 x 104]). Granulocyte engraftment occurred (ANC > 0.5 x 109/L) at a median of 10 days (range: 9-34 days), and the granulocyte engraftment of the UCB occurred in 21 days (range: 13-57 days). Complete UCB chimerism was observed in 37 days (range: 11-186 days) (previously double complete chimerism, presence of third-party donor and of cord) and platelet engraftment > 20 x 109/L in 33 days (range: 13 98 days) and > 50 x 109/L in 58 days (range: 14-106 days). Overall 3-year survival reached 51%, and 5 10 year-survival was 47% (plateau). Disease-free survival was 48% at three years, and 45% at 5 to 10 years; the mean follow-up of survivors was 48 months (range: 13-123 months). (Kaplan-Meier). In conclusion, early granulocyte recovery occurred thanks to a foster engraftment of hematopoietic stem from the third-party donor, which are not HLA-restricted; this is associated with a lower morbidity and mortality from infections secondary to neutropenia. There was also a high rate of engraftment and final full UCB chimerism, even with non-histocompatible UCB units (2/6 HLA mismatches) and with relatively low cell counts. In most cases, a single unit of UCB was sufficient. The incidence of severe GVHD and the percentage of relapses have been low. Opportunistic infections have occurred over a long period of time. This procedures makes allogeneic hematopoietic transplantation accessible to almost all patients.

Neurotrophin-3 production promotes human neuroblastoma cell survival by inhibiting TrkC-induced apoptosis

Tropomyosin-related kinase receptor C (TrkC) is a neurotrophin receptor with tyrosine kinase activity that was expected to be oncogenic. However, it has several characteristics of a tumor suppressor: its expression in tumors has often been associated with good prognosis; and it was recently demonstrated to be a dependence receptor, transducing different positive signals in the presence of ligand but inducing apoptosis in the absence of ligand. Here we show that the TrkC ligand neurotrophin-3 (NT-3) is upregulated in a large fraction of aggressive human neuroblastomas (NBs) and that it blocks TrkC-induced apoptosis of human NB cell lines, consistent with the idea that TrkC is a dependence receptor. Functionally, both siRNA knockdown of NT-3 expression and incubation with a TrkC-specific blocking antibody triggered apoptosis in human NB cell lines. Importantly, disruption of the NT-3 autocrine loop in malignant human neuroblasts triggered in vitro NB cell death and inhibited tumor growth and metastasis in both a chick and a mouse xenograft model. Thus, we believe that our data suggest that NT-3/TrkC disruption is a putative alternative targeted therapeutic strategy for the treatment of NB.

Cord blood transplants supported by co-infusion of mobilized hematopoietic stem cells from a third-party donor

This open label clinical study provides updated evaluation of the strategy of single unit cord blood transplants (CBTs) with co-infusion of third-party donor (TPD) mobilized hematopoietic stem cells (MHSC). Fifty-five adults with high-risk hematological malignancies, median age 34 years (16-60 years) and weight 70 kg (43-95 kg), received CBTs (median 2.39 x 10(7) total nucleated cell (TNC) per kg and 0.11 x 10(6) CD34+ per kg) and TPD-MHSC (median 2.4 x 10(6) CD34+ per kg and 3.2 x 10(3) CD3+ per kg). Median time to ANC and to CB-ANC >0.5 x 10(9)/l as well as to full CB-chimerism was 10, 21 and 44 days, with maximum cumulative incidences (MCI) of 0.96, 0.95 and 0.91. Median time to unsupported platelets >20 x 10(9)/l was 32 days (MCI 0.78). MCI for grades I-IV and III-IV acute GVHD (aGVHD) were 0.62 and 0.11; 12 of 41 patients (29%) who are at risk developed chronic GVHD, becoming severely extensive in three patients. Relapses occurred in seven patients (MCI=0.17). The main causes of morbi-mortality were post-engraftment infections. CMV reactivations were the most frequent, their incidence declining after the fourth month. Five-year overall survival and disease-free survival (Kaplan-Meier) were 56 % and 47% (63% and 54% for patients <or=40 years). In conclusion, CBT with single units of relatively low cell content and 0-3 HLA mismatches is feasible as a first choice option for adult patients who lack a readily available adequate adult donor.

EphrinB3 is an anti-apoptotic ligand that inhibits the dependence receptor functions of EphA4 receptors during adult neurogenesis

Eph receptors have been implicated in regulating a diverse array of cellular functions in the developing nervous system. Recently, Eph receptors have been shown to promote cell death in adult germinal zones; however, their mechanisms of action remain ill-defined. In this study, we demonstrate that EphA4 is a new member of the dependence receptors family, which can initiate cell death in the absence of its ligand ephrinB3. Upon removal of its ligand, EphA4 triggers cell death that is dependent on caspase activation as caspase inhibitors prevent cell death. EphA4 itself is cleaved by caspase-3-like caspase in the intracellular domain at position D773/774, which is necessary for cell death initiation as mutation of the cleavage site abolishes apoptosis. In the adult subventricular zone, abolishing ephrinB3 results in increased cell death, while the absence of EphA4 results in excessive numbers of neuroblasts. Furthermore, infusion of soluble ephrinB3 into the lateral ventricle reduced cell death, and together these results support a dependence role for EphA4 in adult neurogenesis.

The TrkC receptor induces apoptosis when the dependence receptor notion meets the neurotrophin paradigm

The TrkC/NT-3 receptor/ligand pair is believed to be part of the classic neurotrophic theory claiming that neuronal death occurs by default when neurotrophic factors become limited, through loss of survival signals. Here, we show that TrkC is a dependence receptor and, as such, induces caspase-dependent apoptotic death in the absence of NT-3 in immortalized cells, a proapoptotic activity inhibited by the presence of NT-3. This proapoptotic activity of TrkC relies on the caspase-mediated cleavage of the intracellular domain of TrkC, which permits the release of a proapoptotic fragment. This fragment induces apoptosis through a caspase-9-dependent mechanism. Finally, we show that the death of dorsal root ganglion (DRG) neurons provoked by NT-3 withdrawal is inhibited when TrkC-proapoptotic activity is antagonized. Thus, the death of neurons upon disappearance of NT-3 is not only due to a loss of survival signals but also to the active proapoptotic activity of the unbound TrkC dependence receptor.

Idiopathic dilated cardiomyopathy. Elastic parallel element dysfunction as a physiopathological hypothesis for ventricular failure

BACKGROUND

Idiopathic dilated cardiomyopathy is a disease of unknown etiology, although the viral-immunologic pathogenesis has recently emerged as an important hypothesis. Its distinctive anatomopathologic features are: macroscopically, a great ventricular dilation with little hypertrophy, and microscopically marked diffuse interstitial fibrosis not observed in other pathologic entities with dilation. Hemodynamically, its main characteristic is a progressive loss of the systolic function, although the diastolic function is also impaired. To date it is accepted that in dilated states ventricular remodeling occurs due to sliding of fiber with a maximal sarcomere distention; it is also assumed that the ventricular dysfunction is due to a primary deficit in contractility caused by the injury and loss of myocites.

HYPOTHESIS

The aggressive agent mainly attacks the interstitial tissue, thus damaging the elastic parallel element structures. This results in a loss of absorbing power during diastole, starting a progressive dilation which results in maximum sarcomere distention, and compromises the ventricular function. The organ response is to create a new parallel element, which results in an increased fibrosis which also compromises this function.

Donor leukocyte infusions for treatment of relapsed acute myeloid leukemia after allogeneic bone marrow transplantation

A 24-year-old man with acute myelomonocytic leukemia (AML-M4) who relapsed 6 months after an allogeneic BMT was treated with chemotherapy followed by donor leukocyte infusions (4.19 x 10(8) mononuclear cells/kg). The patient developed grade II acute GVHD that responded to therapy with CsA and prednisone. Chimerism was assessed by PCR amplification of the MCT 118 hypervariable region. Fourteen months after donor leukocyte infusions the patient remains in complete remission, without any morphologic and cytogenetic evidence of leukemia, and with a complete donor chimerism. This case shows that donor leukocyte infusions are an effective therapy for some acute myeloid leukemia patients who relapse after allogeneic BMT.

[Treatment with fludarabine of chronic refractory lymphoid leukemia]

PURPOSE

New antimetabolic drugs, purine-analogous, have been introduced in the treatment of advanced or refractory cases of chronic lymphocytic leukaemia (CLL), fludarabine (FLU) being one of such drugs. The results attained with FLU in 6 cases of refractory CLL are reported.

PATIENTS AND METHODS

The efficacy and toxicity of FLU was evaluated in 6 patients (median age 63 years) between March 1993 and March 1994. Five patients were in stage III-IV and one in stage II of the Rai's system, and they were refractory to the usual treatment. The dosis used here was 30 mg/sq m/day, for 5 days every 4 weeks, up to a total of 6 therapeutic courses. The response was assessed after 3 and 6 courses. Anti-infectious prophylaxis was made with co-trimoxazole, monthly benzathine penicillin G and isoniazid in Mantoux-positive patients. The response criteria were those given by the NIC Working Group for CLL.

RESULTS

The patients received 2 to 6 courses. None of them attained complete remission: 1 had nodular remission, 2 had partial remission, 2 responded partially although not reaching criteria for partial remission (1 died of pancytopenia), and 1 had disease progression and died after the second course. Fast and important reduction of the lymphocyte count as well as the CD4 lymphocytes was present in all cases. Bone-marrow infiltration decreased strikingly in 2 cases and the platelet count improved in 3 cases and worsened in 2 others. The following toxicity was recorded: 2 patients had nausea, 5 had neutropenia (below 500 x 10(9)/L in 3 instances) and 4 had thrombocytopenia (lower than 40 x 10(9)/L in one case). In 26 therapeutic courses there were 10 febrile episodes (1 for pneumonia, 1 for gastroenteritis and 8 without any septic foci); 1 patient developed pulmonary tuberculosis after completing the treatment and one patient died of posttransfusion graft versus host disease after splenectomy once she had completes six courses.

CONCLUSION

This experience confirms the efficacy of FLU in the treatment of refractory B-CLL patients and is in agreement with previous reports as no response is initiated after the 3rd course. The lymphocyte count decreases quickly and strikingly. Depletion of CD4 lymphocytes along with neutropenia and hypogammaglobulinaemia make these patients highly sensitive to all types of infection, chiefly by opportunistic germs, so adequate anti-infectious prophylaxis is of great importance. The two patients with pre-treatment haemoglobin and platelet values lower than 10 g/dL and 40 x 10(9)/L, respectively, were the only ones in need of transfusion. No cumulative myelosuppression was appreciated.

Gastric Castleman's disease with a lupus-like circulating anticoagulant

We report the case of a 13-yr-old patient with retarded growth and a 2-yr background of asthenia, anorexia, and fever, whose laboratory data revealed anemia, thrombocytosis, an elevated erythrocyte sedimentation rate, ferropenia, hyperglobulinemia, hyperfibrinogenemia, and presence of a lupus-like circulating anticoagulant. Clinical studies revealed a tumor-like overgrowth in the gastric wall, and surgery confirmed its subserosal localization in the gastric fundus. After total removal of the mass, the systemic manifestations disappeared. The pathological study revealed the existence of the hyaline-vascular variety of Castleman's disease. Having reviewed the medical literature, we have not found a single unquestionable case of gastric Castleman's disease, although three other cases have been described as gastric pseudolymphoma which, when analyzed, could correspond to typical cases of Castleman's disease. Likewise, this is the second case associated with a circulating anticoagulant of lupoid characteristics. We conclude that Castleman's disease should be included in the differential diagnosis of gastric lesions of lymphoid nature and in the series of processes associated with lupus anticoagulant.

Defective neutrophil mobility in the May-Hegglin anomaly

A case of May-Hegglin anomaly is reported in which functional studies of PMN cells showed abnormalities consisting of impairment of chemotactic and chemokinetic responses, random mobility being otherwise normal. These abnormalities seem unrelated to microtubule system dysfunction or to abnormal cell deformability, since no defect was observed in the concanavalin A (Con A) surface receptors and no improvement of directional movement resulted when filters of larger pore size were used in the assays. Other possible mechanisms of the functional defect, such as abnormal membrane receptors to kinetic signals or metabolic abnormalities cannot be excluded. PMN function should be studied in additional cases in order to ascertain if these findings are a constant feature in the May-Hegglin anomaly, a syndrome in which undue susceptibility to infection has not been reported.