Method and Apparatus for the Automated Delivery of Continuous Neural Stem Cell Trails Into the Spinal Cord of Small and Large Animals

BACKGROUND

Immature neurons can extend processes after transplantation in adult animals. Neuronal relays can form between injected neural stem cells (NSCs) and surviving neurons, possibly improving recovery after spinal cord injury (SCI). Cell delivery methods of single or multiple bolus injections of concentrated cell suspensions thus far tested in preclinical and clinical experiments are suboptimal for new tract formation. Nonuniform injectate dispersal is often seen due to gravitational cell settling and clumping. Multiple injections have additive risks of hemorrhage, parenchymal damage, and cellular reflux and require additional surgical exposure. The deposition of multiply delivered cells boluses may be uneven and discontinuous.

OBJECTIVE

To develop an injection apparatus and methodology to deliver continuous cellular trails bridging spinal cord lesions.

METHODS

We improved the uniformity of cellular trails by formulating NSCs in hyaluronic acid. The TrailmakerTM stereotaxic injection device was automatized to extend a shape memory needle from a single-entry point in the spinal cord longitudinal axis to "pioneer" a new trail space and then retract while depositing an hyaluronic acid-NSC suspension. We conducted testing in a collagen spinal models, and animal testing using human NSCs (hNSCs) in rats and minipigs.

RESULTS

Continuous surviving trails of hNSCs within rat and minipig naive spinal cords were 12 and 40 mm in length. hNSC trails were delivered across semi-acute contusion injuries in rats. Transplanted hNSCs survived and were able to differentiate into neural lineage cells and astrocytes.

CONCLUSION

The TrailmakerTM creates longitudinal cellular trails spanning multiple levels from a single-entry point. This may enhance the ability of therapeutics to promote functional relays after SCI.

First Human Implantation of a Bioresorbable Polymer Scaffold for Acute Traumatic Spinal Cord Injury: A Clinical Pilot Study for Safety and Feasibility

BACKGROUND AND IMPORTANCE

A porous bioresorbable polymer scaffold has previously been tested in preclinical animal models of spinal cord contusion injury to promote appositional healing, spare white matter, decrease posttraumatic cysts, and normalize intraparenchymal tissue pressure. This is the first report of its human implantation in a spinal cord injury patient during a pilot study testing the safety and feasibility of this technique (ClinicalTrials.gov Identifier: NCT02138110).

CLINICAL PRESENTATION

A 25-year-old man had a T11-12 fracture dislocation sustained in a motocross accident that resulted in a T11 American Spinal Injury Association Impairment Scale (AIS) grade A traumatic spinal cord injury. He was treated with acute surgical decompression and spinal fixation with fusion, and enrolled in the spinal scaffold study. A 2 × 10 mm bioresorbable scaffold was placed in the spinal cord parenchyma at T12. The scaffold was implanted directly into the traumatic cavity within the spinal cord through a dorsal root entry zone myelotomy at the caudal extent of the contused area. By 3 months, his neurological examination improved to an L1 AIS grade C incomplete injury. At 6-month postoperative follow-up, there were no procedural complications or apparent safety issues related to the scaffold implantation.

CONCLUSION

Although longer-term follow-up and investigation are required, this case demonstrates that a polymer scaffold can be safely implanted into an acutely contused spinal cord. This is the first human surgical implantation, and future outcomes of other patients in this clinical trial will better elucidate the safety and possible efficacy profile of the scaffold.

ABBREVIATIONS

AIS, American Spinal Injury Association Impairment ScaleSCI, spinal cord injurytSCI, traumatic spinal cord injury.

Role of IL-18 in acute lung inflammation

We have examined the role of IL-18 after acute lung inflammation in rats caused by intrapulmonary deposition of IgG immune complexes. Constitutive IL-18 mRNA and protein expression (precursor form, 26 kDa) were found in normal rat lung, whereas in inflamed lungs, IL-18 mRNA was up-regulated; in bronchoalveolar (BAL) fluids, the 26-kDa protein form of IL-18 was increased at 2-4 h in inflamed lungs and remained elevated at 24 h, and the "mature" protein form of IL-18 (18 kDa) appeared in BAL fluids 1-8 h after onset of inflammation. ELISA studies confirmed induction of IL-18 in inflamed lungs (in lung homogenates and in BAL fluids). Prominent immunostaining for IL-18 was found in alveolar macrophages from inflamed lungs. When rat lung macrophages, fibroblasts, type II cells, and endothelial cells were cultured in vitro with LPS, only the first two produced IL-18. Intratracheal administration of rat recombinant IL-18 in the lung model caused significant increases in lung vascular permeability and in BAL content of neutrophils and in BAL content of TNF-alpha, IL-1beta, and cytokine-induced neutrophil chemoattractant, whereas intratracheal instillation of anti-IL-18 greatly reduced these changes and prevented increases in BAL content of IFN-gamma. Intratracheal administration of the natural antagonist of IL-18, IL-18 binding protein, resulted in suppressed lung vascular permeability and decreased BAL content of neutrophils, cytokines, and chemokines. These findings suggest that endogenous IL-18 functions as a proinflammatory cytokine in this model of acute lung inflammation, serving as an autocrine activator to bring about expression of other inflammatory mediators.

Anti-inflammatory effects of mutant forms of secretory leukocyte protease inhibitor

The secretory leukocyte protease inhibitor (SLPI) is found in a variety of secreted fluids in mammals and is a known inhibitor of serine proteases. Wild-type (WT) SLPI has recently been shown to block nuclear factor kappaB (NF-kappaB) activation in rat lungs and to interfere with the ensuing inflammatory response and recruitment of neutrophils after an intrapulmonary deposition of IgG immune complexes. In this study, WT SLPI and SLPI mutants with various degrees of protease-inhibitory capacity (for trypsin, chymotrypsin, and elastase) were evaluated for their ability to suppress the lung-vascular leak, neutrophil accumulation, and NF-kappaB activation in the lung inflammatory model. The SLPI mutant with Gly(72) (replacing Leu(72) ) lost its ability to block in vivo activation of NF-kappaB, as well as its ability to suppress the lung vascular leak and neutrophil recruitment. The Phe(72) and Gly(20) mutants were as effective as the WT SLPI in suppressing NF-kappaB activation and neutrophil recruitment. The Lys(72) mutant had the most suppressive effects of the lung vascular leak and for neutrophil recruitment into the lung. The in vivo suppressive effects of SLPI mutants on lung vascular permeability, neutrophil recruitment, and NF-kappaB activation appear to be most closely related to their trypsin-inhibiting activity. These data suggest that the suppressive effects of SLPI on the intrapulmonary activation of NF-kappaB and neutrophil recruitment into the lung may be linked to their antiprotease activity, directed, perhaps, at the intracellular proteases.

Protection Against the Mortality Associated with Disease Models Mediated by TNF and IFN-γ in Mice Lacking IFN Regulatory Factor-1

Mortality and cytokine production associated with disease models mediated by TNF- and IFN-γ were studied in mice lacking IFN regulatory factor-1 (IRF-1). IRF-1 knockout (KO) mice showed no mortality after the injection of a dose of LPS lethal in intact control mice (LD95). KO mice showed lower circulating levels of TNF and IFN-γ than controls. KO mice also showed lower TNF and IFN-γ mRNA in the spleen or liver than controls. KO mice had smaller spleens than controls, which contained similar percentage but lower absolute count of macrophages and lower percentage and absolute count of NK cells. IRF-1 KO mice survived longer than controls after the coinjection of LPS and galactosamine. IRF-1 KO mice also showed less mortality than controls after the injection of Con A and in a model of cerebral malaria. After the injection of a lethal dose of TNF (LD88), mortality was similar between KO and intact mice. Mortality was also similar after the coinjection of two nonlethal doses of TNF and IFN-γ, a lethal combination (LD100). This study shows that the lack of IRF-1 protects against the mortality associated with disease models mediated by TNF and IFN-γ but has no effect on the mortality directly induced by TNF and IFN-γ. The lack of IRF-1 appears to result in impaired production of TNF and IFN-γ, reflecting a down-regulation of gene expression in the liver and spleen as well as a reduction in the number of splenic cells.

Protection against the mortality associated with disease models mediated by TNF and IFN-gamma in mice lacking IFN regulatory factor-1

Mortality and cytokine production associated with disease models mediated by TNF- and IFN-gamma were studied in mice lacking IFN regulatory factor-1 (IRF-1). IRF-1 knockout (KO) mice showed no mortality after the injection of a dose of LPS lethal in intact control mice (LD95). KO mice showed lower circulating levels of TNF and IFN-gamma than controls. KO mice also showed lower TNF and IFN-gamma mRNA in the spleen or liver than controls. KO mice had smaller spleens than controls, which contained similar percentage but lower absolute count of macrophages and lower percentage and absolute count of NK cells. IRF-1 KO mice survived longer than controls after the coinjection of LPS and galactosamine. IRF-1 KO mice also showed less mortality than controls after the injection of Con A and in a model of cerebral malaria. After the injection of a lethal dose of TNF (LD88), mortality was similar between KO and intact mice. Mortality was also similar after the coinjection of two nonlethal doses of TNF and IFN-gamma, a lethal combination (LD100). This study shows that the lack of IRF-1 protects against the mortality associated with disease models mediated by TNF and IFN-gamma but has no effect on the mortality directly induced by TNF and IFN-gamma. The lack of IRF-1 appears to result in impaired production of TNF and IFN-gamma, reflecting a down-regulation of gene expression in the liver and spleen as well as a reduction in the number of splenic cells.

PEG-rHuMGDF promotes multilineage hematopoietic recovery in myelosuppressed mice

PEG-rHuMGDF administered to normal mice is a lineage-specific growth factor for megakaryocytes and platelets as judged by morphologic examination of hematologic cells in marrow and peripheral blood smears. The purpose of this study was to document that PEG-rHuMGDF in myelosuppressed mice promotes multilineage hematopoietic recovery. High-dose 5-fluorouracil (5-FU) in mice results in profound myelosuppression and 0-30% survival. Mice receiving a single dose of PEG-rHuMGDF (1000 microg/kg) 1 day after 5-FU (225 mg/kg) demonstrate an increased survival (76% vs 27% in control mice at 14 days). Compared to surviving controls, PEG-rHuMGDF-treated mice not only show the expected higher platelet counts, but also increased marrow colony-forming unit granulocyte-macrophage, increased multilineage marrow cellularity, and increased neutrophil, monocyte, and lymphocyte counts in peripheral blood. PEG-rHuMGDF- and vehicle-treated mice both develop hepatic abscesses after 5-FU treatment, but the abscesses in the PEG-rHuMGDF-treated mice contain more neutrophils, suggesting that myeloid reconstitution contributes to their survival. Furthermore, survival in 5-FU-treated mice is significantly improved by granulocyte colony-stimulating factor and antibiotics, suggesting that infection rather than thrombocytopenia is the predominant cause of death. PEG-rHuMGDF after 5-FU promotes survival accompanied by accelerated lymphohematopoietic repopulation, suggesting that PEG-rHuMGDF, a lineage-specific thrombopoietic factor in normal mice, promotes multilineage hematopoietic recovery in myelosuppressed mice.

Corynebacterium parvum- and Mycobacterium bovis Bacillus Calmette and Guerin-induced granuloma formation in mice lacking CD4 and CD8

Granuloma formation is a T-cell-dependent inflammatory response that is important in the host defense against intracellular bacteria. The role of CD4 and CD8 molecules in the development of Corynebacterium parvum- and Mycobacterium bovis Bacillus Calmette and Guerin (BCG)-induced granulomas was examined in CD4/CD8 knockout (KO) mice. CD4/CD8 KO mice developed a greater granulomatous response to heat-killed C. parvum and heat-killed BCG than did control mice. Thus, granuloma formation is not dependent upon the presence of CD4 and CD8. On the other hand, CD4/CD8 KO mice challenged with live BCG showed initially fewer and smaller granulomas but later more and larger granulomas than control mice. CD4/CD8 KO mice had a greater BCG load than control mice. The absence of CD4 and CD8 therefore impaired the host defense against infection with BCG. alphabeta T-cells were present in the granulomas of both CD4/CD8 KO and control mice in similar numbers. Also the production of IFN-gamma mRNA was similar in the two groups. In conclusion, CD4 and CD8 are not essential to the granulomatous response against C. parvum and BCG, but contribute to the host defense against live BCG infection.

The prolonged hematologic effects of a single injection of PEG-rHuMGDF in normal and thrombocytopenic mice

A single injection of > or =10 microg/kg PEG-rHuMGDF in mice causes a dose-dependent increase in circulating platelets beginning on day 3 and peaking on days 5-6. The mean platelet volume and platelet distribution width at doses > or =100 microg/kg initially increase in a dose-dependent fashion and later decrease. However, the mean platelet volume does not change when platelets are incubated with PEG-rHuMGDF in vitro. The number of marrow megakaryocytes increases in a dose-dependent fashion as early as day 1 and peaks on day 3. Marrow megakaryocyte colony-forming units (CFU-Meg) do not increase on days 1-3 at a dose of 100 microg/kg (a dose that increases platelet numbers two- to threefold and may be clinically relevant), but the relative frequency of high ploidy megakaryocytes and the proportion of large marrow megakaryocytes (29-50 microm in diameter) increases. After a dose of 1,000 microg/kg the percentage of megakaryocytes in mitosis peaks at 24-48 hours and the percentage of megakaryocytes incorporating BrdU is maximal at 48 hours, the relatively delayed peak of BrdU incorporation most likely representing endomitosis. The relative frequency of type II and III megakaryocytes peaks on days 3 and 4, respectively. Pharmacokinetic analysis of PEG-rHuMGDF shows peak serum concentrations at 2-4 hours and a terminal half-life of 11.4+/-2.5 hours. A single injection of PEG-rHuMGDF ameliorates carboplatin-induced megakaryocytopenia and thrombocytopenia in a dose-response dependent fashion. In conclusion, a single injection of PEG-rHuMGDF increases megakaryocyte and platelet production in normal and myelo-suppressed mice.

Intravenous keratinocyte growth factor protects against experimental pulmonary injury

Keratinocyte growth factor (KGF) administered by intratracheal instillation is well documented to stimulate the proliferation of alveolar and bronchial cells. In the present study, intravenous KGF was also shown to stimulate the proliferation of alveolar and bronchial cells in mice and rats, although to a lesser degree than intratracheal KGF. Despite the decreased potency of intravenous KGF on pulmonary cell 5-bromo-2'-deoxyuridine incorporation compared with intratracheal KGF, intravenous KGF was very effective in preventing experimental bleomycin-induced pulmonary dysfunction, weight loss, and mortality in either mice or rats and experimental hyperoxia-induced mortality in mice. The effectiveness of intravenous administration of KGF in preventing lung injury suggests that the mechanisms of the protective effect of KGF may involve more than pulmonary cell proliferation and also suggests the potential use of systemic KGF for clinical trials in settings of pulmonary injury.

Keratinocyte growth factor decreases pulmonary edema, transforming growth factor-beta and platelet-derived growth factor-BB expression, and alveolar type II cell loss in bleomycin-induced lung injury

Keratinocyte growth factor (KGF), a potent growth factor for type II pneumocytes and Clara cells, has been shown to prevent the end-stage pulmonary fibrosis and mortality in a rat model of bleomycin-induced lung injury. In this study, protective effects of KGF were explored during the earlier course of bleomycin-induced lung injury by studying protein exudation in alveolar edema fluids, pulmonary expression of transforming growth factor-beta (TGF beta) and platelet-derived growth factor-BB (PDGF-BB), and changes in type II pneumocytes and Clara cells after i.t. (intratracheal) bleomycin injection following KGF- or saline-pretreatment in rats. Total protein in bronchoalveolar lavage (BAL) fluids after bleomycin injury from KGF-pretreated rats was significantly lower than the levels in saline-pretreated rats. TGF beta protein in BAL fluids which peaked at day 3 after i.t. bleomycin in saline-pretreated lungs was not significantly increased at any time points in KGF-pretreated rats. PDGF-BB protein in whole lung tissues of KGF-pretreated rats also remained near normal throughout the course after i.t. bleomycin, in contrast to the significant increase in saline-pretreated rats. Numbers of type II pneumocytes and Clara cells in KGF-pretreated lungs after a high dose of bleomycin were close to the normal in intact lungs. At the same dose of bleomycin injury, type II pneumocytes in saline-pretreated lungs were markedly decreased, while the number of Clara cells in these rats was relatively preserved as the pre-injury level. In conclusion, KGF prevents bleomycin-induced end-stage pulmonary injury and mortality probably at least partly by decreasing protein-rich pulmonary edema, protein expression of fibrogenic cytokines TGF beta and PDGF-BB, and type II cell loss during the course of lung injury.

Keratinocyte growth factor protects mice from chemotherapy and radiation-induced gastrointestinal injury and mortality

Keratinocyte growth factor (KGF) stimulates the proliferation and differentiation of epithelial cells including those of the gastrointestinal tract. Although chemotherapeutics and radiation exposure kill rapidly proliferating tumor cells, rapidly dividing normal cells of the host's gastrointestinal tract are also frequently damaged, leading to the clinical condition broadly termed "mucositis." In this report, recombinant human KGF used as a pretreatment in several mouse models of chemotherapy and/or radiation-induced gastrointestinal injury significantly improved mouse survival. Using multiple-dose 5-fluorouracil, methotrexate, and radiation in combination and total body radiation alone models, KGF increased survival by 55% or greater. In the models that used chemotherapy with or without radiation, KGF significantly ameliorated weight loss after injury and accelerated weight gain during recovery. The basis of these systemic benefits appears to be due in part to the trophic effects of the growth factor on the intestinal epithelium because KGF pretreatment caused an increase in measures of mucosal thickness (villus height and crypt depth) that persisted during the course of 5-fluorouracil chemotherapy. Treatment with KGF also afforded a 3.5-fold improvement in crypt survival in the small intestine, suggesting that KGF also has a direct effect on the crypt stem cells. These data indicate that KGF may be therapeutically useful to lessen the intestinal side effects of current cancer therapy regimens.

Regulatory effects of interleukin-6 in immunoglobulin G immune-complex-induced lung injury

Interleukin-6 (IL-6) is a cytokine produced in response to a variety of inflammatory stimuli. Although IL-6 is often observed in increased amounts in acute respiratory distress syndrome, its role in the development of lung injury is unclear. The role of IL-6 was studied in the rat model of lung injury induced by the intra-alveolar deposition of IgG immune complexes. IL-6 induction, as determined by Northern blot analysis and bioactivity, was found as a function of time during the course of development of injury. Recombinant IL-6 instilled intratracheally at commencement of injury led to substantial reductions in lung vascular permeability, neutrophil accumulation, and levels of tumor necrosis factor (TNF)-alpha and macrophage inflammatory protein (MIP)-2 in bronchoalveolar lavage fluids. Conversely, blocking of intrinsic IL-6 by a neutralizing antibody resulted in increases in lung vascular permeability, neutrophil content, and TNF-alpha levels in bronchoalveolar lavage fluids. Rat alveolar macrophages stimulated in vitro with lipopolysaccharide in the presence of IL-6 showed a significant reduction in TNF-alpha expression. Together, these findings suggest that IL-6 acts as an intrinsic regulator of lung inflammatory injury after deposition of IgG immune complexes and that the protective effects of exogenously administered IL-6 may be in part linked to suppressed TNF-alpha production.

Keratinocyte growth factor ameliorates cyclophosphamide-induced ulcerative hemorrhagic cystitis

To determine whether keratinocyte growth factor (KGF), an epithelial and urothelial growth factor, ameliorates cyclophosphamide (CP)-induced cystitis in rats, KGF (5 mg/kg) was injected in rats as a single i.v. injection 24 h prior to i.p. injection of CP (200 mg/kg). Bladders were evaluated histologically 48 h after CP injection, and KGF pretreatment was found to almost completely prevent CP-induced ulcerative hemorrhagic cystitis. Urinary KGF levels were measured by ELISA, and KGF was found to be undetectable in control urine, but it was found to appear in the urine of KGF-treated rats at 8 h, with a peak concentration of approximately 10 ng/ml. Bilateral nephrectomy did not diminish the proliferative effect of KGF on urothelium, suggesting that the contribution of urinary KGF to urothelial proliferation is insignificant. In conclusion, systemic administration of KGF is protective against CP-induced cystitis. Although KGF appears in the urine, urinary KGF is not necessary for the proliferative action of KGF on urothelium.

Proliferation induced by keratinocyte growth factor enhances in vivo retroviral-mediated gene transfer to mouse hepatocytes

Retroviral gene transfer to liver without prior injury has not yet been accomplished. We hypothesized that recombinant human keratinocyte growth factor would stimulate proliferation of hepatocytes and allow for efficient in vivo gene transfer with high titer murine Moloney retroviral vectors. This report shows that 48 h after intravenous injection of keratinocyte growth factor, hepatocyte proliferation increased approximately 40-fold compared to non-stimulated livers. When keratinocyte growth factor treatment was followed by intravenous injection of high titer (1 x 10(8) colony forming units/ml) retrovirus coding for the Escherichia Coli beta-galactosidase gene, there was a 600-fold increase in beta-galactosidase expression, with 2% of hepatocytes transduced. Thus, by exploiting the mitogenic properties of keratinocyte growth factor, retrovirus-mediated gene transfer to liver may be accomplished in vivo without the use of partial hepatectomy or pretreatment with other toxins to induce hepatocyte cell division.

Keratinocyte growth factor ameliorates radiation- and bleomycin-induced lung injury and mortality

Keratinocyte growth factor (KGF) is a growth factor for type II pneumocytes. Type II pneumocyte hyperplasia, a common reaction to lung injury, has been postulated to play an important role in lung repair. The potential protective effect of KGF was therefore studied in rat models of radiation- and bleomycin-induced lung injury. Intratracheal instillation of KGF (5 mg/kg) 72 and 48 hours before 18 Gy of bilateral thoracic irradiation did not significantly improve survival, although histology showed less pneumonitis and fibrosis in KGF-pretreated as compared with control-irradiated rats. Intratracheal pretreatment with KGF in rats receiving intratracheal bleomycin (2.5 U) improved survival at 3 weeks to 100% (20/20 rats) from 40% (8/20 rats) in controls. All KGF-pretreated rats receiving bleomycin were well at 3 weeks and without histological evidence of pulmonary fibrosis whereas the 8 surviving control rats exhibited severe respiratory distress. Finally, in the most lethal challenge to the lung, rats pretreated with intratracheal KGF or saline were challenged with a combination of bleomycin (1.5 U) and bilateral thoracic irradiation (18 Gy). KGF-pretreated rats did not begin to die or show signs of respiratory distress until 7 weeks, whereas all saline-pretreated control rats receiving radiation and bleomycin died within approximately 4 weeks with severe respiratory distress and weight loss. In conclusion, radiation- and bleomycin-induced pulmonary injury and respiratory death are ameliorated by KGF pretreatment, suggesting a protective role for KGF-induced type II pneumocyte proliferation in lung injury.

Corynebacterium parvum- and Mycobacterium bovis bacillus Calmette-Guerin-induced granuloma formation is inhibited in TNF receptor I (TNF-RI) knockout mice and by treatment with soluble TNF-RI

The aim of this study was to examine the role of TNF receptor I (TNF-RI) in the pathogenesis of heat-killed Corynebacterium parvum- and live bacillus Calmette-Guerin (BCG)-induced granulomas. Granuloma formation was analyzed in TNF-RI knockout mice and after treatment with soluble TNF-RI (sTNF-RI). TNF-RI knockout mice injected with C. parvum or BCG developed fewer and smaller granulomas than wild-type control mice. Mice treated with sTNF-RI from days 7 to 13 after injection of C. parvum or BCG developed fewer and smaller granulomas than saline-treated control mice. Established granulomas regressed in rats treated with sTNF-RI from days 10 to 13 after injection of C. parvum. In conclusion, TNF signaling via TNF-RI contributes to the pathogenesis of C. parvum- and BCG-induced granulomas. sTNF-RI inhibits the development of granulomas and can cause the regression of established granulomas.

Corynebacterium parvum- and Mycobacterium bovis bacillus Calmette-Guerin-induced granuloma formation is inhibited in TNF receptor I (TNF-RI) knockout mice and by treatment with soluble TNF-RI

The aim of this study was to examine the role of TNF receptor I (TNF-RI) in the pathogenesis of heat-killed Corynebacterium parvum- and live bacillus Calmette-Guerin (BCG)-induced granulomas. Granuloma formation was analyzed in TNF-RI knockout mice and after treatment with soluble TNF-RI (sTNF-RI). TNF-RI knockout mice injected with C. parvum or BCG developed fewer and smaller granulomas than wild-type control mice. Mice treated with sTNF-RI from days 7 to 13 after injection of C. parvum or BCG developed fewer and smaller granulomas than saline-treated control mice. Established granulomas regressed in rats treated with sTNF-RI from days 10 to 13 after injection of C. parvum. In conclusion, TNF signaling via TNF-RI contributes to the pathogenesis of C. parvum- and BCG-induced granulomas. sTNF-RI inhibits the development of granulomas and can cause the regression of established granulomas.

Experimental extrinsic allergic alveolitis and pulmonary angiitis induced by intratracheal or intravenous challenge with Corynebacterium parvum in sensitized rats

Extrinsic allergic alveolitis and pulmonary sarcoidosis are granulomatous diseases of the lung for which clinical presentation and anatomic site of granuloma formation differ. Extrinsic allergic alveolitis is caused by inhaled antigens, whereas the nature and source of the inciting antigen in sarcoidosis is unknown. To test the hypothesis that the route via which antigen is introduced to the lung contributes to the clinicopathological presentation of pulmonary granulomatous disease, rats immunized with intravenous (i.v.) Corynebacterium parvum were challenged after 2 weeks with either intratracheal (i.t.) or i.v. C. parvum. The granulomatous inflammation elicited by i.t. challenge predominantly involved alveolar spaces and histologically simulated extrinsic allergic alveolitis. In contrast, the inflammation induced by i.v. challenge was characterized by granulomatous angiitis and interstitial inflammation simulating sarcoidosis. Elevations of leukocyte counts and TNF levels in bronchoalveolar fluid, which reflect inflammation in the intra-alveolar compartment, were much more pronounced after i.t. than after i.v. challenge. Tumor necrosis factor, interleukin-6, CC chemokine, CXC chemokine, and adhesion molecule mRNA and protein expression occurred in each model. In conclusion, i.t. or i.v. challenge with C. parvum in sensitized rats caused pulmonary granulomatous inflammation that was histologically similar to human extrinsic allergic alveolitis and sarcoidosis, respectively. Although the soluble and cellular mediators of granulomatous inflammation were qualitatively similar in both disease models, the differing anatomic source of the same antigenic challenge was responsible for differing clinicopathological presentations.

Radiation-induced lung injury in vivo: expression of transforming growth factor-beta precedes fibrosis

Cytokine release from irradiated cells has been postulated to start soon after irradiation preceding detectable clinical and pathological manifestation of lung injury. The expression of transforming growth factor beta (TGF beta), a fibrogenic and radiation-inducible cytokine, was studied from 1-16 weeks after the 15 and 30 Gray (Gy) of thoracic irradiation to rats. Thoracic irradiation caused an increase in TGF beta protein in bronchoalveolar lavage (BAL) fluid peaking at 3-6 weeks as compared to sham-irradiated control rats. Steady state TGF beta mRNA expression as shown by whole lung northern blot assay paralleled the TGF beta protein expression in BAL fluid. The peak of TGF beta protein increase in BAL fluid between 3 and 6 weeks coincided with the initial influx of inflammatory cells in BAL fluid, but preceded histologically discernable pulmonary fibrosis that was not apparent until 8-10 weeks after irradiation. In conclusion. TGF beta and mRNA and protein upregulation preceded the radiation-induced pulmonary fibrosis, suggesting a pathogenetic role in the development of radiation fibrosis.

Platelet-derived growth factor causes pulmonary cell proliferation and collagen deposition in vivo

Platelet-derived growth factor (PDGF) is postulated to play a role in the pathophysiology of pulmonary fibrosis. Recombinant human PDGF-BB administered as a single intratracheal injection in rats causes an increase in peribronchial and perivascular stromal cells on days 2 and 3 after injection as evaluated by hematoxylin and eosin histology and 5-bromodeoxyuridine incorporation. Proliferation of bronchial epithelial cells and arterial smooth muscle cells, although not evident by routine histological examination alone, is detected on days 2 and 3 by increased 5-bromodeoxyuridine incorporation. A mild increase in 5-bromodeoxyuridine labeling is observed in peripheral alveolar parenchyma after injection of PDGF. The proliferative peribronchial and perivascular mesenchymal cells appear by light microscopic and ultrastructural criteria to be fibroblasts that are immunoreactive for vimentin but negative for alpha-smooth muscle actin and desmin. Daily intratracheal injection of PDGF-BB for 3 days causes a slightly more pronounced peribronchial and perivascular spindle cell proliferation accompanied by collagen deposition as evaluated by Masson's trichrome stain. PDGF-induced increases in cellularity and collagen resolve within 5 days after the last PDGF injection. In conclusion, intratracheal injection of PDGF-BB causes transient proliferation of pulmonary mesenchymal and epithelial cells accompanied by collagen deposition.

Systemic hematologic effects of PEG-rHuMGDF-induced megakaryocyte hyperplasia in mice

PEG-rHuMGDF injected daily in normal mice causes a rapid dose-dependent increase in megakaryocytes and platelets. At the same time that platelet numbers are increased, the mean platelet volume (MPV) and platelet distribution width (PDW) can be either decreased, normal, or increased depending on the dose and time after administration. Thus, PEG-rHuMGDF at a low dose causes decreases in MPV and PDW, MGDF at an intermediate dose causes an initial increase followed by a decrease in MPV and PDW, and PEG-rHuMGDF at higher doses causes an increase in MPV and PDW followed by a gradual normalization of these platelet indices. In addition to the expected thrombocytosis after 7 to 10 days of daily injection of high doses of PEG-rHuMGDF, a transient decrease in peripheral red blood cell numbers and hemoglobin is noted accompanied in the bone marrow by megakaryocytic hyperplasia, myeloid hyperplasia, erythroid and lymphoid hypoplasia, and deposition of a fine network of reticulin fibers. Splenomegaly, an increase in splenic megakaryocytes, and extramedullary hematopoiesis accompany the hematologic changes in the peripheral blood and marrow to complete a spectrum of pathologic features similar to those reported in patients with myelofibrosis and megakaryocyte hyperplasia. However, all the PEG-rHuMGDF-initiated hematopathology including the increase in marrow reticulin is completely and rapidly reversible upon the cessation of administration of PEG-rHuMGDF. Thus, transient hyperplastic proliferation of megakaryocytes does not cause irreversible tissue injury. Furthermore, PEG-rHuMGDF completely ameliorates carboplatin-induced thrombocytopenia at a low-dose that does not cause the hematopathology associated with myelofibrosis.

The intratracheal administration of endotoxin: X. Dexamethasone downregulates neutrophil emigration and cytokine expression in vivo

Intratracheal instillation of endotoxin (LPS) causes acute pulmonary inflammation characterized by the accumulation of plasma proteins and leukocytes within the pulmonary airways. The synthetic glucocorticoid dexamethasone 1) inhibits the LPS-initiated vascular leak of plasma proteins into the airspace, 2) inhibits the LPS-initiated emigration of neutrophils and lymphocytes into the airspace in a dose-dependent fashion, and 3) inhibits LPS-initiated mRNA and/or bronchoalveolar lavage protein expression of cytokines (TNF, IL-1 and IL-6) and chemokines (MIP-1 alpha, MIP-2 and MCP-1). In conclusion, dexamethasone inhibits both the vascular and cellular aspects of acute inflammation by downregulation of a broad spectrum of inflammatory cytokines and chemokines.

Platelet-derived growth factor-BB induces renal tubulointerstitial myofibroblast formation and tubulointerstitial fibrosis

Tubulointerstitial fibrosis correlates closely with renal function, although the mechanism regulating tubulointerstitial fibrogenesis remains poorly understood. Since platelet-derived growth factor (PDGF) is a growth factor for fibroblasts, we examined the effect of daily (for 7 days) PDGF-AA or PDGF-BB administration on renal tubulointerstitial architecture in rats. PDGF-AA administration at a dose of 5 mg/kg did not affect the renal tubulointerstitium. By comparison, PDGF-BB induced dose-dependent renal tubulointerstitial cell proliferation and fibrosis. At 5 mg/kg, PDGF-BB increased BrdU labeling in tubulointerstitial fibroblasts at 24 hours (19-fold), which peaked at 72 hours (23-fold) with bromodeoxyuridine uptake returning to control values by 7 days. Tubulointerstitial proliferation was associated with the differentiation of these cells into myofibroblasts as evidenced by alpha-smooth muscle actin expression beginning on day 3. The expression of alpha-smooth muscle actin peaked on day 5 and had markedly declined by day 21. In addition, apoptotic cells were identified within the tubulointerstitium on day 3 and progressively increased through day 7, suggesting that the disappearance of myofibroblasts may have occurred through apoptosis. These changes were accompanied by increased expression of alpha 1 (III) collagen mRNA and interstitial accumulation of type III collagen within the renal cortex. By morphometric analysis, an approximately twofold increase in collagen III immunolabeling within the interstitial compartment was evident at 24 hours and peaked on days 5 to 7 (approximately fourfold). These data suggest that PDGF-BB may be an important mediator of tubulointerstitial hyperplasia and fibrosis.

Pulmonary malformation in transgenic mice expressing human keratinocyte growth factor in the lung

Expression of human keratinocyte growth factor (KGF/FGF-7) was directed to epithelial cells of the developing embryonic lung of transgenic mice disrupting normal pulmonary morphogenesis during the pseudoglandular stage of development. By embryonic day 15.5(E15.5), lungs of transgenic surfactant protein C (SP-C)-KGF mice resembled those of humans with pulmonary cystadenoma. Lungs were cystic, filling the thoracic cavity, and were composed of numerous dilated saccules lined with glycogen-containing columnar epithelial cells. The normal distribution of SP-C proprotein in the distal regions of respiratory tubules was disrupted. Columnar epithelial cells lining the papillary structures stained variably and weakly for this distal respiratory cell marker. Mesenchymal components were preserved in the transgenic mouse lungs, yet the architectural relationship of the epithelium to the mesenchyme was altered. SP-C-KGF transgenic mice failed to survive gestation to term, dying before E17.5. Culturing mouse fetal lung explants in the presence of recombinant human KGF also disrupted branching morphogenesis and resulted in similar cystic malformation of the lung. Thus, it appears that precise temporal and spatial expression of KGF is likely to play a crucial role in the control of branching morphogenesis during fetal lung development.

Intratracheal injection of endotoxin and cytokines. IX. Contribution of CD11a/ICAM-1 to neutrophil emigration

Intratracheal injection of endotoxin [lipopolysaccharide (LPS)] in rats causes acute inflammation characterized by the emigration of neutrophils (PMNs) into the bronchoalveolar airspace. Antibody to PMN adhesion molecule CD11a inhibited LPS-initiated PMN accumulation in bronchoalveolar lavage (BAL) fluid by 32% (P < 0.001). Antibody to the endothelial CD11a counterreceptor intercellular adhesion molecule-1 (ICAM-1) inhibited LPS-initiated PMN accumulation in BAL fluid by 66% (P < 0.0001). Combined antibody blockade of ICAM-1 and the C-X-C chemokine cytokine-induced neutrophil chemoattractant (CINC) inhibited LPS-initiated PMN emigration by 80%, significantly more than antibody against either ICAM-1 or CINC alone. To study the relative contribution of alveolar macrophages and PMNs to intra-alveolar tumor necrosis factor (TNF), the LPS-induced TNF in BAL fluid was measured after depletion of circulating PMNs with a cytolytic antibody to CD18. Although the anti-CD18 antibody completely abrogated LPS-initiated PMN emigration into BAL fluid, TNF levels in BAL fluid were unaffected, suggesting that alveolar macrophages are the predominant cellular source of LPS-induced TNF production. In conclusion, 1) CD11a, ICAM-1, and CINC play major roles in the LPS-initiated emigration of PMNs into the bronchoalveolar space, and 2) the TNF that drives ICAM-1 and CINC expression is derived largely from alveolar macrophages rather than PMNs.

Megakaryocyte growth and development factor ameliorates carboplatin-induced thrombocytopenia in mice

Megakaryocyte growth and development factor (MGDF) administered intraperitoneally (IP) to mice causes a dose-dependent thrombocytosis accompanied by a decrease in mean platelet volume. MGDF increases the number of megakaryocytes in the bone marrow and spleen. MGDF does not affect the circulating number of leukocytes. Carboplatin, a chemotherapeutic agent that causes thrombocytopenia in humans, administered to mice as a single IP injection at a nonlethal dose causes a significant, but reversible thrombocytopenia. The carboplatin-induced thrombocytopenia is accompanied by an increase in circulating endogenous MGDF that precedes the return of circulating platelets to a normal level. MGDF mRNA is constitutively present in the liver. After carboplatin treatment, hepatic MGDF mRNA does not increase in concordance with circulating MGDF. Circulating soluble MGDF receptor levels (c-mpl) do not change significantly during the course of carboplatin-induced thrombocytopenia. MGDF injected IP once daily beginning 1 day after injection of carboplatin reverses carboplatin-induced thrombocytopenia in a dose-dependent fashion. The normalization of circulating platelet numbers in carboplatin plus MGDF-treated mice is accompanied by a normalization of megakaryocyte numbers in the bone marrow. In conclusion, MGDF, by increasing the number of marrow megakaryocytes and circulating platelets is an effective therapy for carboplatin-induced thrombocytopenia in mice.

Hematologic effects of stem cell factor (SCF) and leukemia inhibitory factor (LIF) in vivo: LIF-induced thrombocytosis in SCF-primed mice

Stem cell factor (SCF) administered as daily bolus injections in dose-response experiments in mice causes a progressive and dramatic dose-dependent panleukocytosis characterized by neutrophilia, eosinophilia, monocytosis, and lymphocytosis. SCF causes circulating platelet numbers to be dose-dependently increased after 2 weeks of daily injections. Leukemia inhibitory factor (LIF) administered as daily bolus injections in mice causes a peripheral leukopenia that is largely due to peripheral lymphopenia. LIF causes thrombocytosis peaking after approximately 1 w. Coinjection of SCF and LIF for 1 to 2 wk in mice does not cause a much greater thrombocytosis than the maximum thrombocytosis achievable with SCF or LIF alone. On the other hand, daily injection of SCF for 5 days followed by daily injection of LIF for 5 to 6 d in mice causes a very substantial increase in platelets that was lineage-specific in terms of not being accompanied by a generalized leukocytosis. In contrast, only a very modest thrombocytosis was noted in SCF-primed LIF-treated rats. LIF causes a large increase in the cytoplasmic volume of splenic megakaryocytes in mice, but not in rats. In conclusion, SCF-induced priming followed by LIF-induced maturation of megakaryocytes causes a substantial selective increase in the numbers of circulating platelets in mice.

Expression of interleukin-1 receptor antagonist protein in malignant lymphomas. An immunohistochemical study

OBJECTIVE

Interleukin-1 (IL-1) receptor antagonist (IL-1ra) is a naturally occurring modulator of IL-1 that functions by competitively binding to IL-1 receptors without producing biologic effects. Interleukin-1 is believed to be a mediator involved in production of constitutional symptoms in patients with malignant lymphoma. Because we know of no study regarding IL-1ra expression in lymphomas, we tried to demonstrate the presence of IL-1ra in lymphomas using immunohistochemistry.

DESIGN

Anti-IL-1ra monoclonal antibody was applied to paraffin sections of Hodgkin's disease and non-Hodgkin's lymphoma (NHL) with avidin-biotin complex method.

RESULTS

Interleukin-1 receptor antagonist was found to be present primarily in benign reactive histiocytes in neoplastic tissue. Positivity for IL-1ra was found in 12 (67%) of 18 cases of Hodgkin's disease and 53 (29%) of 184 cases of NHL. The positivity rate varied in different subtypes of NHL. Three percent (1 in 30) of follicular small cleaved-cell lymphomas contained IL-1ra-expressing histiocytes, whereas 52% (17 of 33) of diffuse mixed-cell and 27% (12 of 44) of diffuse large-cell lymphomas contained IL-1ra-positive histiocytes. Nine of 13 (69%) cases of high-grade NHLs contained IL-1ra-expressing histiocytes. Among cases of NHL, the higher-grade NHL cases showed higher percentages of positivity.

CONCLUSIONS

The findings further support the hypothesis that IL-1 may play a role in producing constitutional symptoms.

Intratracheal administration of endotoxin and cytokines. VI. Antiserum to CINC inhibits acute inflammation

Cytokine-induced neutrophil chemoattractant (CINC), a chemotactic molecule of the interleukin (IL)-8 family, is known to be induced in the rat in response to tumor necrosis factor (TNF), IL-1, and lipopolysaccharide (LPS). Intratracheal injection of endotoxin (LPS) is shown to cause CINC mRNA expression in pulmonary tissue, peaking after 2 h, and CINC protein expression in bronchoalveolar lavage (BAL) fluid, peaking after 2-4 h. Intratracheal injection of synthetic CINC causes acute inflammation that is abrogated by coinjection of antiserum to purified natural rat CINC. Intratracheal injection of antiserum to CINC inhibits intratracheal LPS- and IL-1-induced neutrophil emigration into BAL fluid by approximately 60-70%. Despite the anti-inflammatory activity of anti-CINC antiserum, TNF is elevated in the lavage fluid of rats receiving anti-CINC, suggesting that CINC may act in a negative feedback loop to downregulate TNF expression. Intratracheal injection of antiserum to CINC combined with intravenous injection of anti-E-selectin antibody inhibits intratracheal LPS- and IL-1-induced neutrophil emigration into BAL fluid by approximately 75-85%. CINC-mediated chemotactic activity and E-selectin-mediated adherence of neutrophils to endothelium contribute significantly to the pathogenesis of LPS-initiated acute inflammation.

Intratracheal injection of LPS and cytokines. V. LPS induces expression of LIF and LIF inhibits acute inflammation

Lipopolysaccharide (LPS) injected into the trachea of rats was found to induce the secretion of leukemia inhibitory factor (LIF) into bronchoalveolar lavage (BAL) fluid with a maximum expression of LIF after 2-12 h. The acute pulmonary neutrophilic inflammation caused by the intratracheal injection of bacterial endotoxin (LPS) could be inhibited by the intratracheal coinjection of recombinant LIF. Compared with intratracheal injection of LPS alone, intratracheal coinjection of LIF and LPS decreases the number of BAL neutrophils obtained 6 h later by approximately 50% (P < 0.0001). LIF decreased the amount of the proinflammatory cytokine tumor necrosis factor (TNF), but not the amount of the anti-inflammatory cytokine interleukin (IL)-6, in the BAL fluid of LPS-injected rats. Similarly, intravenous LIF was found to decrease TNF expression, but increase IL-6 expression, in the serum of rats receiving intravenous LPS. Intravenous LIF, even in the absence of LPS, was found to cause IL-6 expression. In conclusion, intratracheal LPS initiates the secretion of endogenous LIF into the alveolar space where LIF may contribute to the downregulation of LPS-initiated acute neutrophilic inflammation by downregulating expression of TNF. LIF may down-regulate LPS-initiated TNF expression at least in part indirectly by upregulating expression of IL-6, a cytokine known to downregulate LPS-initiated TNF expression.

Intratracheal administration of endotoxin and cytokines: VIII. LPS induces E-selectin expression; anti-E-selectin and soluble E-selectin inhibit acute inflammation

E-selectin is an inducible endothelial adhesion molecule that binds neutrophils. E-selectin mRNA is not constitutively detectable in the lungs of rats. Intratracheal injection of LPS induces pulmonary E-selectin mRNA expression at 2-4 h. Intratracheal injection of LPS followed at 2 and 4 h by intravenous injection of mouse F(ab')2 or F(ab') anti-E-selectin monoclonal antibody inhibits the emigration of neutrophils into the bronchoalveolar space at 6 h by 50-70%. TNF and IL-6 bioactivity are not decreased in bronchoalveolar lavage fluid after treatment with anti-E-selectin antibody as compared to controls, suggesting that the anti-E-selectin does not affect the magnitude of the LPS-initiated cytokine cascade. Intratracheal injection of LPS followed at 2 and 4 h by intravenous injection of soluble E-selectin inhibits neutrophilic emigration at 6 h by 64%, suggesting that endogenous soluble E-selectin shed from activated endothelium may play a role in the endogenous down-regulation of acute inflammation. E-selectin-mediated adhesion of neutrophils to endothelium appears crucial to the full development of the acute inflammation response.

Intratracheal administration of endotoxin and cytokines. VII. The soluble interleukin-1 receptor and the soluble tumor necrosis factor receptor II (p80) inhibit acute inflammation

Intratracheal administration of endotoxin (LPS) causes acute neutrophilic inflammation via induction of pulmonary tumor necrosis factor alpha (TNF) and interleukin-1 (IL-1) expression. In the present study, the anti-inflammatory activity of soluble IL-1 receptor (sIL-1r) and soluble TNF receptor p80 (sTNFr-p80) in LPS-induced acute pulmonary inflammation was investigated. The sIL-1r coinjected intratracheally with LPS in rats significantly inhibits neutrophilic exudation into bronchoalveolar lavage (BAL) fluid by 47% after 6 hr compared to injection of LPS alone. TNF and IL-6 in the same BAL fluids were both lowered by approximately 50% after intratracheal coinjection of sIL-1r and LPS as compared to LPS alone. In the same model, the sTNFr-p80 inhibited acute inflammation. Paradoxically, TNF levels in BAL fluids were generally elevated after the intratracheal coinjection of LPS and monomeric sTNFr-p80 compared to injection of LPS injection alone. The combined anti-inflammatory effect of sIL-1r and sTNFr-p80 at the maximally effective individual doses is not significantly greater than the effect of either soluble receptor alone.

Keratinocyte growth factor induces pancreatic ductal epithelial proliferation

Keratinocyte growth factor (KGF) causes a proliferation of pancreatic ductal epithelial cells in adult rats after daily systemic administration for 1 to 2 weeks. Even before the proliferation of intralobular ducts is histologically evident, KGF also induces proliferating cell nuclear antigen expression within the ductal epithelium of intercalated, intralobular, and interlobular ducts. KGF also causes incorporation of 5-bromodeoxyuridine in ductal epithelial cells. Epithelial cell proliferation is histologically most prominent at the level of the intralobular ducts adjacent to and within the islets of Langerhans. Pancreatic ductal proliferation is not histologically apparent in rats sacrificed 7 to 10 days after the cessation of KGF administration. The pancreatic hormones insulin, glucagon, somatostatin, and pancreatic polypeptide are normally distributed within islets that demonstrate intrainsular ductal proliferation. The proliferating ductal epithelium does not show endocrine differentiation as evidenced by the lack of immunoreactivity for pancreatic hormones. KGF is a potent in vivo mitogen for pancreatic ductal epithelial cells.

Inositol polyanions. Noncarbohydrate inhibitors of L- and P-selectin that block inflammation

Selectins are cell adhesion molecules known to support the initial attachment of leukocytes to inflamed vascular endothelium through their recognition of carbohydrate ligands such as the tetrasaccharide sialyl Lewisx (Neu5Ac alpha 2-3Gal beta 1-4(Fuc alpha 1-3)GlcNAc-). In the present study, we describe the inhibition of L- and P-selectin function by inositol polyanions, simple 6-carbon ring structures that have multiple ester-linked phosphate or sulfate groups. In a purified component competition assay, binding of L- and P-selectin-Ig fusion proteins to immobilized bovine serum albumin-sialyl Lewisx neoglycoprotein was inhibited by inositol hexakisphosphate (InsP6, IC50 = 2.1 +/- 1.4 microM and 160 +/- 40 microM), by inositol pentakisphosphate (InsP5, IC50 = 1.4 +/- 0.2 and 260 +/- 40 microM), and by inositol hexakissulfate (InsS6, IC50 = 210 +/- 80 microM and 2.8 +/- 0.9 mM); E-selectin-Ig binding was unaffected. Inositol polyanions diminished the adhesion of LS180 colon carcinoma cells to plates coated with L- and P-selectin-Ig but not with E-selectin-Ig. Inositol polyanions blocked polymorphonuclear leukocyte (PMN) adhesion to COS cells expressing recombinant transmembrane P-selectin but not to those expressing E-selectin. In addition, inositol polyanions diminished PMN adhesion to activated endothelial cells under rotation-induced shear stress, a process known to require L-selectin function. In vivo, the effects of inositol polyanions were studied in two murine models of acute inflammation. Intravenously administered InsP6 (two doses of 40 mumol/kg) inhibited PMN accumulation in thioglycolate-induced inflammation (55 +/- 10% inhibition) and in zymosan-induced inflammation (61 +/- 4% inhibition). InsP5 and InsS6 also inhibited inflammation in these models, although higher doses were required for InsS6. In conclusion, inositol polyanions are noncarbohydrate small molecules that inhibit L- and P-selectin function in vitro and inflammation in vivo.

Keratinocyte growth factor is a growth factor for mammary epithelium in vivo. The mammary epithelium of lactating rats is resistant to the proliferative action of keratinocyte growth factor

Keratinocyte growth factor (KGF) is a member of the fibroblast growth factor (FGF) family. KGF is secreted by stromal cells and affects epithelial but not mesenchymal cell proliferation. KGF injected intravenously was found to cause dramatic proliferation of mammary epithelium in the mammary glands of rats. KGF causes ductal neogenesis and intraductal epithelial hyperplasia but not lobular differentiation in nulliparous female rats. KGF causes ductal and lobular epithelial hyperplasia in male rats. KGF causes proliferation of ductal and acinar cells in the mammary glands of pregnant rats. On the other hand, the ductal epithelium of lactating postpartum rats is resistant to the proliferative action of KGF. The mammary glands of lactating rats did not express less KGF receptor mRNA than the glands of pregnant rats, suggesting that the resistance of the ductal epithelium to KGF during lactation is not related to KGF receptor mRNA down-regulation. The mammary glands of both pregnant and postpartum lactating rats express KGF mRNA with more KGF present in the glands of lactating rats. In conclusion, the KGF and KGF receptor genes are expressed in rat mammary glands and recombinant KGF is a potent growth factor for mammary epithelium.

Indefinite survival of human skin allografts in patients with long-term immunosuppression

The transplantation of a sufficient quantity of good quality skin is of great clinical importance. Severe burn patients lack adequate skin donor sites to cover their wounds with autografts. Patients with severe injuries and burns of areas such as the entire face are presently reconstructed with multiple full- or split-thickness skin grafts. The final result is a patchwork appearance of skin with inferior qualities to normal full-thickness facial skin. Before structures such as hands should be transplanted, each individual tissue component should be evaluated to determine whether the tissue will survive and function with immunosuppression. Skin is obviously an important part of the hand. One hypothesis tested is the ability of transplanted human skin to survive indefinitely with long-term immunosuppression. The early detection of rejection of transplanted organs is paramount in reversing the rejection phenomena and hence saving the transplanted organ. Another hypothesis tested is the ability of a synchronously placed, same-donor, same-recipient skin graft to be used to detect rejection of a transplanted organ. As the skin and kidney from the same donor have similar antigens and the transplantation of both these tissues is to the same recipient and immunological system, it is hypothesized that there will be a correlation of rejection between the transplanted skin and the transplanted organ. To test the above hypotheses a small skin graft was placed on renal transplant patients synchronously with renal transplantation. The skin allografts were followed by direct observation and biopsy at regular intervals and at the time of suspected rejection. The patients were treated with the usual renal transplant immunosuppressant drugs.(ABSTRACT TRUNCATED AT 250 WORDS)

Keratinocyte growth factor is a growth factor for type II pneumocytes in vivo

Keratinocyte growth factor (KGF) administered as a single intratracheal injection causes a prominent dose-dependent proliferation of type II alveolar epithelial cells in the lungs of adult rats. The increase in mitotically active alveolar cells histologically appears as a micropapillary epithelial cell hyperplasia after 2 d and peaks after 3 d in the form of monolayers of cuboidal epithelial cells lining alveolar septae. Proliferating cell nuclear antigen immunohistochemistry confirmed the profound proliferative response induced by KGF. The hyperplastic alveolar lining cells contain immunoreactive surfactant protein B and are ultrastructurally noted to contain lamellar inclusions characteristic of surfactant-producing type II pneumocytes. Mild focal bronchiolar epithelial hyperplasia is noted but is much less striking than the proliferation of type II pneumocytes. Large airways are unaffected by KGF. Daily intravenous injection of KGF is also able to cause pneumocyte proliferation. The normal adult rat lung constitutively expresses both KGF and KGF receptor mRNA, suggesting that endogenous KGF may be implicated in the paracrine regulation of the growth of pneumocytes. In conclusion, KGF rapidly and specifically induces proliferation and differentiation of type II pneumocytes in the normal adult lung.

Cytokine expression in the placenta. The role of interleukin 1 and interleukin 1 receptor antagonist expression in chorioamnionitis and parturition

Interleukin 1 (IL-1) is known to be present in placental tissue and is implicated as an endogenous mediator of inflammation and parturition. This study was undertaken to assess the role of IL-1 receptor antagonist (IL-1ra) in the placenta. Placentas with acute chorioamnionitis, with meconium staining, and without significant inflammation were examined for immunohistochemical expression of IL-1 and IL-1ra. Interleukin 1 and IL-1ra immunoreactivity was variably noted in the amnion, trophoblast, vascular smooth muscle, stromal cells, fibrinoid, and decidua in all placentas. Interleukin 1 immunoreactivity was less intense than IL-1ra immunoreactivity, and both were generally more intense in acute chorioamnionitis. Interleukin 1 receptor antagonist was detected (approximately 5 to 6 ng/mL) in the amniotic fluid of pregnant women at term. Colocalization of IL-1 and IL-1ra in normal and inflamed placentas suggests that the balance between these proinflammatory and anti-inflammatory mediators plays a role in parturition as well as in the pathogenesis of acute inflammation. An increase and/or imbalance in the IL-1 and IL-1ra expression associated with chorioamnionitis may precipitate preterm labor.

Intratracheal administration of endotoxin and cytokines. IV. The soluble tumor necrosis factor receptor type I inhibits acute inflammation

Endotoxin lipopolysaccharide (LPS) administered intratracheally to rats causes pulmonary tumor necrosis factor alpha (TNF) and interleukin-1 (IL-1) production and results in acute broncho-alveolar neutrophilic inflammation. In the present study, the recombinant human TNF soluble receptor type I (sTNFrI) co-injected intratracheally with LPS is shown to inhibit significantly (P < 0.0001) the number of neutrophils in bronchoalveolar lavage specimens at 6 hours as compared to intratracheal injection of LPS alone. The sTNFrI was at least as effective as the recombinant human IL-1 receptor antagonist (IL-1ra) as an inhibitor of acute inflammation. Inhibition of LPS-induced acute inflammation by the combination of sTNFrI and IL-1ra was not significantly more than the inhibition afforded by sTNFrI alone. Intratracheal co-injection of sTNFrI with LPS unexpectedly increased TNF levels in BAL specimens, perhaps by changing the normal catabolism of TNF. On the other hand, co-injection of sTNFrI and LPS decreased IL-6 levels in BAL fluid, most likely by interfering with the induction of IL-6 by TNF. The sTNFrI may prove to be an important pharmacological down-regulator of acute inflammation.

Granulocyte colony-stimulating factor crosses the placenta and stimulates fetal rat granulopoiesis

We studied the effect of recombinant human granulocyte colony-stimulating factor (rhG-CSF) administration to pregnant rats upon fetal and neonatal myelopoiesis. Pregnant rats were treated with rhG-CSF twice daily for 2, 4, and 6 days before parturition. rhG-CSF crossed the placenta and reached peak fetal serum concentrations 4 hours after administration. Peak fetal serum levels were 1,000-fold lower than levels detected in the dam. Hematopoietic effects of rhG-CSF were assessed by cytologic analysis of the newborn blood, spleen, bone marrow, thymus, and liver. White blood cell counts were increased twofold to fourfold in newborns. This increase was due to circulating numbers of polymorphonuclear cells (PMN). rhG-CSF induced a myeloid hyperplasia in the newborn marrow consisting of immature and mature myeloid cells in the day-2 and day-4 treated pups. Bone marrow of pups treated for 6 days contained mostly hyper-segmented PMN with little or no increase in myeloid precursors. An increase in the number of postmitotic (PMN, bands, and metamyelocytes) and mitotic (promyeloblasts, myeloblasts, and metamyeloblasts) myeloid cells in the spleen of neonates was observed. No change was detected in splenic lymphocytes or monocytes. No effect of rhG-CSF was noted in the newborn liver or thymus. These results demonstrate that maternally administered rhG-CSF crosses the placenta and specifically induces bone marrow and spleen myelopoiesis in the fetus and neonate. The significant myelopoietic effects of rhG-CSF at low concentrations in the fetus suggest an exquisite degree of developmental sensitivity to this cytokine and may provide enhanced defense mechanisms to the neonate.

Activated pulmonary vascular neutrophils as early mediators of endotoxin-induced lung inflammation

Pulmonary vascular sequestration of leukocytes has been reported to increase in some models of lung injury, including that induced by gram-negative bacterial lipopolysaccharide (LPS). Neutrophils recruited to the lung likely participate in LPS-induced lung inflammation and associated injury, but the functional activities of these pulmonary vascular neutrophils have not been directly assessed. In the current study, cells were recovered by pulmonary vascular lavage (PVL) of isolated rat lungs, harvested 2 h after intravenous infusion of LPS (3 mg/kg) or saline in intact rats, at which time LPS-induced neutrophil recruitment to the lung could be appreciated histologically but not by airway lavage. Relative concentrations of leukocytes recovered from the pulmonary vasculature by PVL were compared with those present in circulating blood, normalizing for lavage dilution on the basis of erythrocyte counts. Excess neutrophils, lymphocytes, monocytes, and eosinophils were recovered from the pulmonary vasculature of controls, and LPS infusion increased recovery of neutrophils (most prominently), lymphocytes, and monocytes. Compared with cells recovered from controls, PVL neutrophils from LPS-infused animals were primed for increased zymosan-stimulated superoxide generation, determined by ferricytochrome C reduction, and were more adherent to nylon wool columns. Northern blots of extracted RNA demonstrated that LPS infusion also upregulated interleukin-1 beta (IL-1 beta) mRNA expression in PVL leukocyte samples, but not BAL or circulating blood samples. Ficoll-hypaque separation demonstrated that the LPS-induced IL-1 beta signal in PVL leukocytes was derived primarily from polymorphonuclear rather than mononuclear leukocytes. In conclusion, all circulating leukocyte populations are sequestered in rat lungs, and LPS increases pulmonary vascular sequestration of leukocytes, recruiting most prominently an activated pool of neutrophils that are more adherent, primed for increased oxygen radical production, and expressing increased IL-1 beta message. These findings suggest a more prominent role than previously appreciated for sequestered neutrophils in sepsis-induced lung inflammation.

Endotoxin-induced cytokine gene expression in vivo. IV. Expression of interleukin-1 alpha/beta and interleukin-1 receptor antagonist mRNA during endotoxemia and during endotoxin-initiated local acute inflammation

After the intravenous (IV) injection of endotoxin, (lipopolysaccharide [LPS]), in the rat, interleukin-1 alpha/beta (IL-1 alpha/beta) mRNA expression peaks at 1 hour in whole organ RNA preparations of the lung, liver, spleen, and bowel. Interleukin-1 receptor antagonist (IL-1ra) mRNA peaks at 2 to 4 hours, consistent with the hypothesis that IL-1ra acts as an endogenous negative feedback mechanism to downregulate the proinflammatory effects of IL-1. After the intratracheal (IT) injection of LPS, however, IL-1 and IL-1ra mRNA levels in whole lung peak at 6 hours, concurrent with the maximum influx of neutrophils (PMNs) into the bronchoalveolar space. To address the cellular source of IL-1 and IL-1ra mRNA in the lung during acute pneumonitis, mRNA levels were studied in bronchoalveolar lavage (BAL) macrophages incubated with LPS in vitro for 6 hours as compared with BAL cells (95% PMNs) obtained 6 hours after IT injection of LPS. A much greater expression of IL-1 and IL-1ra mRNA was observed in PMN-rich BAL cells obtained after IT injection of LPS, suggesting that PMNs contribute substantially to IL-1 and IL-1ra mRNA expression. Fractionation of alveolar macrophage-enriched and PMN-enriched subpopulations from the BAL cells obtained at 6 hours after IT injection of LPS confirmed that neutrophils are a source of IL-1 and IL-1ra mRNA. The difference in the kinetics of IL-1 and IL-1ra mRNA expression in whole lung RNA preparations after IV and IT injections of LPS is due to the contribution of PMNs that appear in the lung in large numbers after IT injection. Finally, human peripheral blood PMNs were found to express IL-1ra mRNA and protein after in vitro incubation with LPS. PMNs may contribute to the up- and downregulation of their own accumulation by expressing both IL-1 and IL-1ra.

Endotoxin, interleukin-1, and tumor necrosis factor cause neutrophil-dependent microvascular leakage in postcapillary venules

Acute inflammation is characterized mainly by the egress of neutrophils from postcapillary venules and by increased vascular permeability leading to the formation of edema. The microvascular site of increased vascular permeability in local acute inflammatory lesions was investigated after the injection of endotoxin (LPS), interleukin-1 (IL-1), and tumor necrosis factor (TNF) into the dermis overlying the cremasteric and rectus abdominis muscles of rats. LPS caused leakage of colloidal carbon peaking at 3 to 4 hours at the level of the postcapillary venules and capillary leak was variably observed at later time points. IL-1 and TNF also caused postcapillary venular leakage. IL-1 was as potent as LPS and more so than TNF. The microvascular leak caused by LPS, IL-1, and TNF was accompanied by the tissue accumulation of neutrophils, and was neutrophil-dependent because LPS, IL-1, and TNF did not cause vascular labelling in neutropenic rats.

Stem cell factor in combination with granulocyte colony-stimulating factor (CSF) or granulocyte-macrophage CSF synergistically increases granulopoiesis in vivo

Recombinant rat stem cell factor (rrSCF) and recombinant human granulocyte colony-stimulating factor (G-CSF) coinjected for 1 week in rats cause a synergistic increase in mature marrow neutrophils accompanied by a striking decrease in erythroid and lymphoid marrow elements. The spleens of the same rats show increased granulopoiesis as well as increased erythropoiesis as compared with the spleens of rats treated with either growth factor alone. Splenic extramedullary erythropoiesis may act to compensate for the decrease in marrow erythropoiesis. The coinjection of rrSCF and G-CSF causes an increase in marrow mast cells at the end of 1 week, but the increase is much less than in rrSCF-alone-treated rats. The combination of rrSCF and G-CSF increases the rate of release of marrow neutrophils into the circulation and causes a dramatic synergistic peripheral neutrophilia, beginning especially after 4 days of treatment. Colony-forming assays of all experimental groups showed a synergistic increase in colony-forming unit granulocyte-macrophage (CFU-GM) in the marrow, but not in peripheral blood, after coincubation with SCF plus granulocyte-macrophage CSF (GM-CSF) as opposed to GM-CSF alone, showing anatomic compartmentalization between a more primitive marrow CFU-GM subset and a more mature peripheral blood CFU-GM subset. In vivo daily administration of SCF plus GM-CSF results in a synergistic increase in marrow neutrophils, but not the striking synergistic increase in circulating neutrophils that is observed with SCF plus G-CSF.

The hematopoietic and mature blood cells of the rat: their morphology and the kinetics of circulating leukocytes in control rats

Although the morphology of the hematopoietic and circulating blood cells of the rat differs slightly from that of human blood cells, the basophil is the only human blood cell for which the rat does not have a readily recognizable counterpart. The morphological classification of the rat's marrow and peripheral blood cells as based on our experience is described with reference to the differing observations of previous investigators and with comparison to the human hematopoietic system. Examination of the bone marrow and peripheral blood demonstrated that control rats injected i.v. with 1% normal rat serum in sterile saline exhibit a moderate transient lymphopenia as the only significant hematologic fluctuation induced by the stresses of injection, general anesthesia, and tail bleeding. Morphologic quantitation of marrow and peripheral blood cells complements the insights obtained by the culture of marrow cells. An appreciation of the morphology of the rat's blood cells and of the reproducible and quantitative nature of marrow and peripheral blood smear examinations may lead to more in vivo investigations of hematopoiesis and leukocyte trafficking.

Hematologic effects of stem cell factor in vivo and in vitro in rodents

Recombinant rat stem cell factor (rrSCF) administered to rats as a single intravenous injection causes a dose-dependent neutrophilia and lymphocytosis as well as the appearance of immature myeloid cells and occasional blast cells in the circulation. Neutrophilia begins at 2 hours, peaks at 4 to 6 hours, and subsides between 12 and 24 hours. Lymphocytosis occurs at 0.5 hours and has subsided by 2 hours. rrSCF-induced neutrophilia and lymphocytosis are abrogated by boiling, demonstrating that endotoxin-contamination of the rrSCF preparation is not responsible for the observed hematologic effects. The bone marrow at 6 hours after injection of rrSCF shows a left-shifted myeloid and erythroid hyperplasia as evidenced by significant increases in the absolute numbers of morphologically recognizable early myeloid and erythroid precursors. A concurrent decrease in the absolute numbers of mature marrow neutrophils is noted, suggesting that the release of marrow neutrophils contributes to the peripheral neutrophilia. After 2 weeks of daily injections of rrSCF, bone marrow smears demonstrate a remarkable mast cell hyperplasia accompanied by a decrease in total marrow cellularity and by a striking erythroid and lymphoid hypoplasia. rrSCF also causes mast cells to appear in the circulation and causes a systemic increase in embryonic connective tissue-type, but not mucosal-type, mast cells. In vitro long-term culture of lineage-depleted mouse bone marrow cells with rrSCF results in an almost pure outgrowth of mast cells.