Treatment of pseudoarthrosis of the upper limb using expanded mesenchymal stem cells: a pilot study

BACKGROUND

In orthopedic field is growing interest in the use of stem cells: this mesenchymal multipotent line (MSCs) can lead to differentiation into osteocytes and thus the formation of bone tissue. In literature applications of this line are described in injuries of tendons and ligaments, small bony avulsions, nonunion fractures and cartilage defects.

AIM

Utilize MSCs expanded in laboratory in case of atrophic pseudoarthrosis of the upper limb.

MATERIALS AND METHODS

We obtain the amount of cell necessary for the implant by the collaboration with the UO Haematological Department. For the procedure we make a blood sample from the iliac crest bone marrow and a subsequent phase of selection and cultivation of mesenchymal line for 3 weeks, to get a sufficient amount of tissue to be used, which is presented at the time of surgery on a scaffold made by autologous plasma gel and CaCl(2). We reassessed our experience in 8 different types of upper limb fractures result in pseudarthrosis and delayed of consolidation: 4 women and 4 men, average 44 years old followed with a follow-up of 50.3 months. In all cases the site of non-union has been revitalized (by microfractures and drilling) and a synthesis was performed with a rigid plate. So we fill the bone gap with autologous bone and mesenchymal stem cells expanded in the laboratory.

RESULTS

We have a radiographic healing in 8 cases and no adverse events were highlighted.

CONCLUSIONS

Using this cells line we obtained encouraging but certainly not conclusive impressions, according to the limited number of cases and lack of adequate comparative studies. In tissue engineering are also certainly needed further investigations and developments.

Mesenchymal cells inhibit expansion but not cytotoxicity exerted by gamma-delta T cells

BACKGROUND

Multipotent mesenchymal stromal cells (MSCs) exert a relevant immunosuppressive activity by inhibiting T- and B-lymphocytes, natural killer (NK) cells and dendritic cell expansion. Nevertheless, a possible activity on gamma/delta T cells has still not been evaluated. Gamma-delta T lymphocytes play an important role in the control of cancer and they have been shown to be implicated in graft-vs.-host disease. Thus, modulation of activation and proliferation of these cells could be relevant for therapeutic purposes.

MATERIALS AND METHODS

Peripheral blood mononuclear cells from 21 healthy donors were used as source for gamma-delta T cells, expanded in presence of 10 IU mL(-1) interleukin-2 (IL-2) and 1 microM zoledronate. MSCs were recovered from patients undergoing routine total hip replacement surgery, and characterised by flow cytometry. Cytotoxicity on multiple myeloma and melanoma cell lines was assessed by measuring dilution of the carboxyfluorescein diacetate succinimydylester dye (CFSE). Gamma-delta T cells were then incubated with MSCs in contact cultures, and with addition of MSC-conditioned medium.

RESULTS

In this article we confirmed that (1) in vitro expanded gamma-delta T cells play a significant anti-proliferative effect on multiple myeloma and melanoma cells and (2) multipotent mesenchymal stromal cells effectively suppress the ex vivo expansion of T cells carrying a specific T-cell receptor gene (TCR) rearrangement, Vgamma9/Vdelta2, induced by the combination of IL-2 and zoledronate, without interfering with their cytotoxic activity.

DISCUSSION

These findings contribute to explain the activity of ex vivo expanded mesenchymal cells, suggesting that MSCs would interact with gamma-delta T lymphocytes.

CONCLUSION

This effect could be relevant in separating graft-vs.-host from the graft-vs.-tumour effect, especially considering the possibility of modulating T-lymphocytes activity by the immunomodulating drugs now available.

PS-341 (Bortezomib) inhibits proliferation and induces apoptosis of megakaryoblastic MO7-e cells

PS-341 (Bortezomib) is a dipeptide boronic acid proteasome inhibitor with antitumor activity that induces apoptosis in different human cancer cell lines. We investigated effects of PS-341 (Bortezomib) on cell proliferation, cell cycle progression, induction of apoptosis and differentiation in a megakaryoblastic (MO7-e) cell line. PS-341 was able to retain NF-kappaB in the cytoplasm and inhibit cell growth (IC(50)=22.5 nM), in a dose/time-dependent way. This anti-proliferative activity resulted to be lineage-specific, because other leukemic cell lines (KG1a, K562/R7, HL60/DNR) were unaffected by the PS-341 treatment. Moreover, PS-341 in MO7-e induced a significant pro-apoptotic effect from 10 nM concentration (40% versus 12% in the control, p<0.05). On the other hand, at lower concentration (5 nM), Bortezomib blocked cell cycle in the G2 phase. Finally, this compound was able to down-regulate WT1 expression. No significant effects on cell differentiation were found. Because a spontaneous NF-kappaB activation has been reported in megakaryocytes from patients affected by myeloproliferative disorders, Bortezomib would so be an attractive therapeutic tool for these malignancies, including essential thrombocythemia or idiopathic myelofibrosis. Preliminary data show an inhibiting activity of Bortezomib in the megakaryocytic colonies formation. Finally, also down-regulation of the WT1 gene Bortezomib-driven could be relevant, because of the role that this gene would play in the pathogenesis of acute and chronic myeloproliferative disorders.

Cell clonality in hypereosinophilic syndrome: what pathogenetic role?

OBJECTIVE

Idiopathic hypereosinophilic syndrome (HES) is a heterogeneous disorder, including either a myeloproliferative or a lymphoproliferative variant (l-HES). In l-HES, T-lymphocytes could be involved in the pathogenesis through several cytokines, including IL5.

METHODS

We assayed both TCR Beta- and delta-rearrangements by fluorescent PCR, characterizing 14 patients affected by HES. Lyn activation (a src-kinase involved in the IL5 pathway) was also tested in 6 cases.

RESULTS

FIP1L1-PDGFRa was detected in 4 cases (28.6%); a clonal TCR was found in 10 cases (71.4%), including cases FIP1L1-PDGFRalpha-positive; four cases did not show any molecular marker. In this series, levels of IL5, IL4, IL2 and gammaIFN were measured, without any significant difference among different subgroups. All pathological samples tested did not show Lyn activation. Immunophenotype was also characterized: only one case showed an atypical CD3-/CD4+ population in the bone marrow.

CONCLUSION

This study would suggest that a real distinction between m- and l-HES is not wholly convincing and that clonal T-cell expansion could not be the "primum movens" but an epiphenomenon in HES.

Synergistic effects of alpha interferon and 1,25 dihydroxyvitamin D3: preliminary evidence suggesting that interferon induces expression of the vitamin receptor

BACKGROUND

To active metabolite of vitamin D3-1,25(OH)2D3-is a well-known differentiation inducer. The addition of this metabolite to sensitive cell cultures inhibits proliferation and induces monocytic-macrophagic differentiation. Alpha interferon may also inhibit proliferation and increase the expression of some surface antigens in some neoplastic cells. In the present report, we describe the synergistic activity of these two drugs on U-937 and on cultured cells from a leukemic patient.

METHODS

Proliferation was studied by 3H-thymidine incorporation; differentiation markers were evaluated immunologically by monoclonal antibodies and by cytochemical tests. Phagocytosis and NBT reduction test were also performed in order to confirm the differentiating properties of these drugs. Finally, the expression of the 1,25(OH)2D3 receptor was evaluated by immunochemical methods.

RESULTS

After culturing these cells for 72 hours in the presence of 1,25(OH)2D3, cell proliferation was reduced and the expression of some phenotypic and functional markers suggested monocytic-macrophagic differentiation. Alpha interferon and 1,25(OH)2D3 synergistically inhibit the proliferation of U-937 cells. Alpha interferon increased the expression of the 1,25(OH)2D3 receptor in U-937 cells.

CONCLUSIONS

The reported results confirm the synergistic activity of INF and 1,25(OH)2D3 on cell proliferation in monoblastic cells. The possible role of the increased expression of the vitamin receptor in cells cultured in the presence of INF is discussed.