This consensus statement is directed to intensivists, hematologists, and oncologists caring for critically ill cancer patients and focuses on the management of these patients.

Objectives: The nervous system modulates the immune response in many autoimmune syndromes by neurogenic inflammation. One of the pivotal mediators is nerve growth factor (NGF), which is known for its effects on neuronal survival and growth. There is considerable evidence that NGF acts as an important mediator of many immune responses. This article reviews the role of NGF in rheumatic diseases and strategies for potential therapeutic interventions.Methods: We conducted a database search using Medline and Medpilot. Eight hundred abstracts containing the keyword NGF and 1 of the following terms were reviewed: arthritis, neurogenic inflammation, rheumatoid arthritis, osteoarthritis, collagen arthritis, arteritis, psoriasis, psoriatic arthritis, Sjogren syndrome, systemic lupus erythematosus, gout, osteoporosis, lower back pain, lumbar disc herniation, nerve root compression, spondyloarthritis, spondylarthropathy, algoneurodystrophy, fibromyalgia, Kawasaki syndrome, polyarteritis nodosa, cytokine, vasculitis, pain, therapy, and antagonist. Articles were analyzed based on relevance and content. Most clinical trials and studies with human specimens were included. Studies with experimental animal models were selected if they contained relevant data.Results: NGF is overexpressed in many inflammatory and degenerative rheumatic diseases. Concentrations differ to some extent and sometimes even show contradictory results. NGF is found in serum, synovial fluid, and cerebrospinal fluid, and tissue specimens. NGF concentrations can be correlated with the extent of inflammation and/or clinical activity in many conditions. In rheumatoid arthritis, NGF levels are significantly higher as compared with osteoarthritis.Conclusions: NGF is a significant mediator and modulator of inflammation. NGF sometimes shows detrimental and sometimes regenerative activity. These findings indicate potential therapeutic interventions using either NGF antagonists or recombinant NGF. (C) 2010 Published by Elsevier Inc. Semin Arthritis Rheum 40:109-126

IGF2 and H19 are imprinted genes in normal human tissue, but many studies have observed a loss of imprinting (LOI) of these genes in tumors as an epigenetic alteration of the DNA, that leads to a biallelic expression predisposing cells to carcinogenesis and tumor growth. The aim of this study was to test the reliability of LightCycler™-assisted Real-time PCR in detecting LOI of IGF2 and H19 in 39 patients with testicular germ cell tumors by comparing these results with the analysis generated by the golden standard restriction fragment length polymorphism (RFLP). With LightCycler™-assisted Real-time PCR for IGF2 44% and for H19 49% of the patients were found to be heterozygous. This was consistent with the results obtained by RFLP, but surprisingly RFLP failed in more than 7% of the patients. In detecting LOI (for IGF2 in 41% and for H19 in 68% of the informative patients) the approach by RFLP was superior, since the results derived from LightCycler™-assisted Real-time PCR showed reliable results in 76 and 10% of the samples concerning IGF2 and H19, respectively. Again, no discrepancy between the results obtained by the two methods occurred. In sum, LightCycler™-assisted Real-time PCR is a sufficiently working approach for the rapid and reliable detection of heterozygosity of IGF2 or H19 gene and identification of LOI of IGF2 and thus may be helpful in conducting large epidemiological studies. However, for the identification of LOI of the H19 gene in this cohort it possesses only restrictive use.

Stem cell fate is influenced by specialized microenvironments that remain poorly defined in mammals. Hematopoietic stem cells reside in a specialized niche that regulates their abundance and fate. Components of the niche have generally been defined in terms of cells and signaling pathways. Osteoblastic cells represent a regulatory cellular component of the hematopoietic stem cell niche that influences stem cell function through Notch activation. We define a role for a matrix glycoprotein, osteopontin (OPN), as a non-cellular constraining factor on hematopoietic stem cells within the bone marrow microenvironment. Osteoblasts that participate in the niche produce varying amounts of OPN in response to stimulation. Using studies that combine OPN-deficient mice and exogenous OPN, we demonstrate that OPN modifies primitive hematopoietic cell number and function in a stem cell–nonautonomous manner. The OPN-null microenvironment was sufficient to increase the number of stem cells associated with increased stromal Jagged1 and Angiopoietin-1 expression and reduced primitive hematopoietic cell apoptosis. The activation of the stem cell microenvironment with parathyroid hormone induced a superphysiologic increase in stem cells in the absence of OPN. Therefore, OPN is a negative regulatory element of the stem cell niche that limits the size of the stem cell pool and may provide a mechanism for restricting excess stem cell expansion under conditions of niche stimulation.

Stem cells reside in a physical microenvironment or niche where a balance of signals controls their proliferation, differentiation and death. Components of the specialized microenvironment have generally been defined in terms of cells and signaling pathways affecting stem cell maintenance or expansion. We have defined a role for a matrix glycoprotein that provides a constraining function on hematopoietic stem cells within the bone marrow microenvironment. Osteopontin (OPN) is an abundant glycoprotein in bone that modifies primitive hematopoietic cell number and function in a stem cell non-autonomous manner. Here we analyzed the role of OPN for regulating stem cell mobilization and pool size in times of G-CSF induced marrow stress, a context close to the clinical setting of stem cell mobilization not well understood so far. Bone marrow stromal cells show an enhanced expression of OPN under stimulation with G-CSF, which prompted us to analyze the role of OPN in G-CSF mediated activation of the stem cell niche. First we treated OPN deficient mice and their wild-type littermates with G-CSF for 5 days. We could observe a significant increased stem cell fraction in the peripheral blood and in the bone marrow in the absence of OPN in comparison to the wild-type controls. To evaluate, if this effect is stroma dependent, we first transplanted wild-type bone marrow into wild-type or OPN-deficient recipients. 6 weeks after transplantation we treated these mice with G-CSF for 5 days and analyzed the peripheral blood and the bone marrow for the contents of primitive hematopoietic cells. Here we could detect a significantly increased stem cell fraction in peripheral blood and bone marrow of the OPN −/− recipients in comparison to wild type controls detected by FACS and functional in vitro stem cell assays. We then transplanted the stressed bone marrow in a competitive repopulation assay into wild-type recipients and observed a significant increase of CD45.2 cells from OPN −/− recipient mice up to 12 weeks after transplantation in comparison to wild-type controls, demonstrating an enhanced G-CSF induced expansion of hematopioetic stem cells in the OPN-deficient stem cell niche. Furthermore, we could observe an enhanced expression of Angiopoietin and N-Cadherin in OPN-deficient bone marrow stromal cells after stimulation with G-CSF in comparison to wild-type controls, supporting the stroma dependent expansion of stem cells in the absence of OPN in the G-CSF stimulated stem cell niche. Therefore, OPN is a restricting element of the stem cell niche limiting the size of the stem cell pool and may provide a dynamic mechanism by which excess stem cell expansion is prevented during times of niche stimulation. These findings may provide new insight into expansion and mobilization of hematopoietic stem cells by G-CSF mediated by components of the stem cell niche.

Stem-cell ageing is thought to contribute to altered tissue maintenance and repair. Older humans experience increased bone marrow failure and poorer haematologic tolerance of cytotoxic injury. Haematopoietic stem cells (HSCs) in older mice have decreased per-cell repopulating activity, self-renewal and homing abilities, myeloid skewing of differentiation, and increased apoptosis with stress. Here we report that the cyclin-dependent kinase inhibitor p16(INK4a), the level of which was previously noted to increase in other cell types with age, accumulates and modulates specific age-associated HSC functions. Notably, in the absence of p16(INK4a), HSC repopulating defects and apoptosis were mitigated, improving the stress tolerance of cells and the survival of animals in successive transplants, a stem- cell-autonomous tissue regeneration model. Inhibition of p16(INK4a) may ameliorate the physiological impact of ageing on stem cells and thereby improve injury repair in aged tissue.

It has been suggested that germline stem cells maintain oogenesis in postnatal mouse ovaries. Here we show that adult mouse ovaries rapidly generate hundreds of oocytes, despite a small premeiotic germ cell pool. In considering the possibility of an extragonadal source of germ cells, we show expression of germline markers in bone marrow (BM). Further, BM transplantation restores oocyte production in wild-type mice sterilized by chemotherapy, as well as in ataxia telangiectasia-mutated gene-deficient mice, which are otherwise incapable of making oocytes. Donor-derived oocytes are also observed in female mice following peripheral blood transplantation. Although the fertilizability and developmental competency of the BM and peripheral blood-derived oocytes remain to be established, their morphology, enclosure within follicles, and expression of germ-cell- and oocyte-specific markers collectively support that these cells are bona fide oocytes. These results identify BM as a potential source of germ cells that could sustain oocyte production in adulthood.

The zinc finger transcription factor GATA-2 plays a fundamental role in generating hematopoietic stem-cells in mammalian development. Less well defined is whether GATA-2 participates in adult stem-cell regulation, an issue we addressed using GATA-2 heterozygote mice that express reduced levels of GATA-2 in hematopoietic cells. While GATA-2(+/-) mice demonstrated decreases in some colony-forming progenitors, the most prominent changes were observed within the stem-cell compartment. Heterozygote bone marrow had a lower abundance of Lin(-) c-kit(+)Sca-1(+)CD34(-) cells and performed poorly in competitive transplantation and quantitative week-5 cobblestone area-forming cell (CAFC) assays. Furthermore, a stem-cell-enriched population from GATA1(+/-) marrow was more quiescent and exhibited a greater frequency of apoptotic cells associated with decreased expression of the antiapoptotic gene Bcl-xL. Yet the self-renewal potential of the +/- stem-cell compartment, as judged by serial transplantations, was unchanged. These data indicate compromised primitive cell proliferation and survival in the setting of a lower GATA-2 gene dose without a change in the differentiation or self-renewal capacity of the stem-cells that remain. Thus, GATA-2 dose regulates adult stem-cell homeostasis by affecting select aspects of stem cell function.

The purpose of this study was to determine the maximum tolerated dose, toxicity profile and anti-tumor activity of paclitaxel in combination with gemcitabine when administered to patients with unresectable locally recurrent or metastatic squamous cell carcinoma of the head and the neck (SCCHN). Twenty-seven patients were treated in a phase I-II study with gemcitabine at a dose of 800 mg/m on days 1 and 8, escalating to a dose of 1,000 mg/m, plus escalating doses of paclitaxel (100, 135 and 175 mg/m) on day 2. Treatment consisted of 6 cycles repeated every 3 weeks. The main toxicity was myelosuppression. Other toxicities were mild and manageable. Due to grade 4 neutropenia at higher doses the recommended dose level of the gemcitabine/paclitaxel combination was 1,000/135 mg/m. Four patients achieved a partial response and no patient had a complete remission, giving an overall response rate of 14.8%. The median time of survival was 24 weeks. We conclude that the combination of paclitaxel and gemcitabine is tolerated, but shows insufficient clinical activity in patients with recurrent and/or metastatic SCCHN to warrant further testing.

Stem cells reside in a specialized niche that regulates their abundance and fate. Components of the niche have generally been defined in terms of cells and signaling pathways. We define a role for a matrix glycoprotein, osteopontin (OPN), as a constraining factor on hematopoietic stem cells within the bone marrow microenvironment. Osteoblasts that participate in the niche produce varying amounts of OPN in response to stimulation. Using studies that combine OPN-deficient mice and exogenous OPN, we demonstrate that OPN modifies primitive hematopoietic cell number and function in a stem cell–nonautonomous manner. The OPN-null microenvironment was sufficient to increase the number of stem cells associated with increased stromal Jagged1 and Angiopoietin-1 expression and reduced primitive hematopoietic cell apoptosis. The activation of the stem cell microenvironment with parathyroid hormone induced a superphysiologic increase in stem cells in the absence of OPN. Therefore, OPN is a negative regulatory element of the stem cell niche that limits the size of the stem cell pool and may provide a mechanism for restricting excess stem cell expansion under conditions of niche stimulation.

Stem cells reside in a physical niche where a balance of signals controls their growth, differentiation and death. Niche components have generally been defined in terms of cells and positive effects on stem cell maintenance or expansion. Here we define a role for a matrix glycoprotein that provides a constraining function in the hematopoietic stem cell niche. Osteopontin (OPN) is an abundant glycoprotein in bone that can function as either cytokine or cell adhesion mediator. It is known to be produced by multiple cells types including osteoblasts, cells recently defined to be a regulatory component of the hematopoietic stem cell niche. Using studies combining OPN deficient mice and exogenous OPN, we demonstrate that OPN modifies primitive hematopoietic cell numbers and function. In OPN deficient mice, increased primitive cell numbers were observed in vivo associated with reduced progenitors and reduced primitive cell apoptotic fraction. To determine whether the effect of OPN deficiency was stroma dependent, we performed in vitro stem cell assays on OPN−/− stroma and observed greater LTC-IC supportive capacity compared with wild type stroma. Furthermore, OPN−/− recipients showed a significantly higher proportion of hematopoietic stem cells after transplantation of OPN+/+ bone marrow in comparison to wild-type recipients, indicating that the OPN null microenvironment was sufficient to increase stem cell number. A reduction in apoptotic fraction was seen in primitive cells in the OPN−/− recipient marrows. A role for OPN in apoptosis was confirmed by exogenous OPN in in-vitro studies. Hypothesizing that OPN may serve as a physiologic constraint on stem cell pool size, we compared OPN−/− with wild type animals following parathyroid hormone activation of the stem cell niche. The expansion of stem cells by PTH was superphysiologic in the absence of OPN. Therefore, OPN is a restricting element of the stem cell niche, limiting the number of stem cells produced by niche activation. Extracellular matrix components such as OPN may serve as modulable, regulatory participants in the stem cell niche.

Relative quiescence is a defining characteristic of hematopoietic stem cells. Reasoning that inhibitory tone dominates control of stem cell cycling, we previously showed that mice engineered to be deficient in the cyclin-dependent kinase inhibitor, p21Cip1/Waf1 (p21), have an increased stem cell pool under homeostatic conditions. Since p21 was necessary to maintain stem cell quiescence and its absence sufficient to permit increased murine stem cell cycling, we tested whether reduction of p21 alone in human adult-derived stem cells could affect stem cell proliferation. We demonstrate here that interrupting p21 expression ex vivo resulted in expanded stem cell number and in vivo stem cell function compared with control, manipulated cells. Further, we demonstrate full multilineage reconstitution capability in cells where p21 expression was knocked down. Therefore, lifting the brake on cell proliferation by altering cell cycle checkpoints provides an alternative paradigm for increasing hematopoietic stem cell numbers. This approach may be useful for relative ex vivo human stem cell expansion.