Floseal only versus in combination in spine surgery: a comparative, retrospective hospital database evaluation of clinical and healthcare resource outcomes.

OBJECTIVE: Flowable agents such as Floseal® (F) are often reserved as adjuncts to non-flowable agents (i.e. gelatin (G) sponges and thrombin (T)) when bleeding is not sufficiently controlled. Based on their perceived positive impact, it is postulated that flowable agents alone may result in better clinical and resource utilization outcomes. Clinical and health-care utilization outcomes were compared in this retrospective analysis of spine surgery cases with charges for Floseal only (FO) and F + G/T. METHODS: The United States Premier Hospital Database was searched for adult spine surgeries performed between October 2010 and September 2015 with FO or F and G/T charges. To obtain an unbiased treatment estimate, 1:1 propensity-score matching was used to identify FO and F + G/T cohorts. The cohorts were compared for rates of intraoperative, perioperative, postoperative and transfusion; blood loss-related, serious and other complications; hospital length-of-stay (LOS), surgical time, and volume of hemostat charged. RESULTS: Among 40,335 spine surgeries, 15,105 FO and F + G/T matched pairs were compared. Significantly (p < 0.0001) lower percentages of FO than F + G/T cases received intraoperative (1.4% vs. 2.5%), perioperative (1.6% vs. 2.8%), postoperative (1.6% vs 3.0%), and any transfusion (2.3% vs. 4.3%). FO cases had significantly less blood loss complications than F + G/T cases (0.5% vs. 0.8%, p = 0.0022) and significantly (p < 0.0001) shorter hospital LOS (-0.45 days), surgical time (-39.0 min), and used less hemostat (-12.5 mL). CONCLUSIONS: Results from this observational hospital database analyses indicate that FO use in spine surgery is associated with lower blood transfusion use and blood loss complications compared to its use with adjunct non-flowable hemostatic agents. The shorter hospital stay, reduced surgical time, and less hemostat volume health-care utilization outcomes that favored FO versus combination use may translate to health system cost savings. Further validation of these findings using controlled clinical trials and cost-consequence studies is warranted. CLINICAL RELEVANCE: The use of flowable hemostatic agents alone may result in better clinical and possibly economic outcomes in spine surgery.

Modulation of dendritic cells using granulocyte-macrophage colony-stimulating factor (GM-CSF) delays type 1 diabetes by enhancing CD4+CD25+ regulatory T cell function.

Abnormalities in DC function are implicated in defective immune regulation that leads to type-1 diabetes (T1D) in NOD mice and humans. In this study, we used GM-CSF and Flt3-L to modulate DC function in NOD mice and observed the effects on T1D development. Treatment with either ligand at earlier stages of insulitis suppressed the development of T1D. Unlike Flt3-L, GM-CSF was more effective in suppressing T1D, even when administered at later stages of insulitis. In vitro studies and in vivo adoptive transfer experiments revealed that CD4+CD25+ T cells from GM-CSF-treated mice could suppress effector T cell response and T1D. This suppression is likely mediated through enhanced IL-10 and TGF-beta1 production. Adoptive transfer of GM-CSF exposed DCs to naive mice resulted in an expansion of Foxp3+ T cells and a significant delay in T1D onset. Our results indicate that GM-CSF acted primarily on DCs and caused an expansion of Foxp3+ Tregs which delayed the onset of T1D in NOD mice.

GM-CSF-induced CD11c+CD8a--dendritic cells facilitate Foxp3+ and IL-10+ regulatory T cell expansion resulting in suppression of autoimmune thyroiditis.

GM-CSF plays an essential role in the differentiation of dendritic cells (DCs). Our studies have shown that GM-CSF treatment can induce semi-mature DCs and CD4+CD25+ regulatory T cells (Tregs) and suppress ongoing autoimmunity in mouse models. In this study, we examined the differences in the potential of GM-CSF to exert tolerogenic function on CD8a+ and CD8a- sub-populations of DCs in vivo. We show that GM-CSF modulates CD8a-, but not CD8a+ DCs in vivo, by inhibiting the surface expression of activation markers MHC II and CD80 and production of inflammatory cytokines such as IL-12 and IL-1beta. Self-antigen [mouse thyroglobulin (mTg)] presentation by GM-CSF-exposed CD8a- DCs to T cells from mTg-primed mice induced a profound increase in the frequency of forkhead box P3 (FoxP3)-expressing T cells compared with antigen presentation by GM-CSF-exposed CD8a+ DCs and control CD8a+ and CD8a- DCs. This tolerogenic property of GM-CD8a- DCs was abrogated when IL-12 was added. GM-CSF-exposed CD8a- DCs could also induce secretion of significantly higher amounts of IL-10 by T cells from mTg-primed mice. Importantly, adoptive transfer of CD8a- DCs from GM-CSF-treated SCID mice, but not untreated mice, into wild-type CBA/J mice prevented the development of experimental autoimmune thyroiditis (EAT) in the recipient animals upon immunization with mTg. Collectively, our results show that GM-CSF renders CD8a- DCs tolerogenic, and these DCs induce Foxp3+ and IL-10+ Tregs.

IL-10-producing CD4+CD25+ regulatory T cells play a critical role in granulocyte-macrophage colony-stimulating factor-induced suppression of experimental autoimmune thyroiditis.

Our earlier study showed that GM-CSF has the potential not only to prevent, but also to suppress, experimental autoimmune thyroiditis (EAT). GM-CSF-induced EAT suppression in mice was accompanied by an increase in the frequency of CD4(+)CD25(+) regulatory T cells that could suppress mouse thyroglobulin (mTg)-specific T cell responses in vitro, but the underlying mechanism of this suppression was not elucidated. In this study we show that GM-CSF can induce dendritic cells (DCs) with a semimature phenotype, an important characteristic of DCs, which are known to play a critical role in the induction and maintenance of regulatory T cells. Adoptive transfer of CD4(+)CD25(+) T cells from GM-CSF-treated and mTg-primed donors into untreated, but mTg-primed, recipients resulted in decreased mTg-specific T cell responses. Furthermore, lymphocytes obtained from these donors and recipients after adoptive transfer produced significantly higher levels of IL-10 compared with mTg-primed, untreated, control mice. Administration of anti-IL-10R Ab into GM-CSF-treated mice abrogated GM-CSF-induced suppression of EAT, as indicated by increased mTg-specific T cell responses, thyroid lymphocyte infiltration, and follicular destruction. Interestingly, in vivo blockade of IL-10R did not affect GM-CSF-induced expansion of CD4(+)CD25(+) T cells. However, IL-10-induced immunosuppression was due to its direct effects on mTg-specific effector T cells. Taken together, these results indicated that IL-10, produced by CD4(+)CD25(+) T cells that were probably induced by semimature DCs, is essential for disease suppression in GM-CSF-treated mice.