Marian J. Sturm

A phase 2 study of allogeneic mesenchymal stromal cells for luminal crohn's disease refractory to biologic therapy

BACKGROUND & AIMS Transplantation of peripheral blood stem cells has been successful therapy for small numbers of patients with Crohns disease (CD), but requires prior myeloconditioning. Mesenchymal stromal cells (MSCs) escape immune recognition, so myeloconditioning is not required before their administration. We investigated the efficacy of allogeneic MSCs in patients with luminal CD. METHODS Our phase 2, open-label, multicenter study included 16 patients (21-55 y old; 6 men) with infliximab- or adalimumab-refractory, endoscopically confirmed, active luminal CD (CD activity index [CDAI], >250). Subjects were given intravenous infusions of allogeneic MSCs (2 × 10(6) cells/kg body weight) weekly for 4 weeks. The primary end point was clinical response (decrease in CDAI >100 points) 42 days after the first MSC administration; secondary end points were clinical remission (CDAI, <150), endoscopic improvement (a CD endoscopic index of severity [CDEIS] value, <3 or a decrease by >5), quality of life, level of C-reactive protein, and safety. RESULTS Among the 15 patients who completed the study, the mean CDAI score was reduced from 370 (median, 327; range, 256-603) to 203 (median, 129) at day 42 (P < .0001). The mean CDAI scores decreased after each MSC infusion (370 before administration, 269 on day 7, 240 on day 14, 209 on day 21, 182 on day 28, and 203 on day 42). Twelve patients had a clinical response (80%; 95% confidence interval, 72%-88%; mean reduction in CDAI, 211; range 102-367), 8 had clinical remission (53%; range, 43%-64%; mean CDAI at day 42, 94; range, 44-130). Seven patients had endoscopic improvement (47%), for whom the mean CDEIS scores decreased from 21.5 (range, 3.3-33) to 11.0 (range, 0.3-18.5). One patient had a serious adverse event (2 dysplasia-associated lesions), but this probably was not caused by MSCs. CONCLUSIONS In a phase 2 study, administration of allogeneic MSCs reduced CDAI and CDEIS scores in patients with luminal CD refractory to biologic therapy. ClinicalTrials.gov number, NCT01090817.

Plasma degradation of platelet-activating factor in severely ill patients with clinical sepsis

ObjectiveTo study the plasma degradation of platelet-activating factor in severely ill patients with clinical sepsis. DesignA prospective, nonrandomized control study. SettingIntensive care unit in a university hospital. PatientsThirteen critically ill male patients with clinical sepsis, due to medical or surgical illness, and ten normal male volunteers were studied. Measurements were repeated in seven patients who survived. Measurements and Main ResultsThe plasma activity of acetylhydrolase, the lipoprotein-associated enzyme that hydrolyses platelet-activating factor to its biologically inactive lyso-derivative was determined using an optimized enzyme assay. The plasma half-life of platelet-activating factor was also measured, along with phospholipase A2 activity, lyso-platelet-activating factor, and serum lipid concentrations. Patient results were compared with those results of normal controls and followed once in survivors. Acetylhydrolase activity in the patient group was significantly lower than in normal subjects (median 34, interquartile range 17 to 54 nmol/min/mL vs. median 60, interquartile range 56 to 80 nmol/min/mL; p < .002), while overall, the plasma half-life of platelet-activating factor did not differ significantly between the groups. However, the half-life of platelet-activating factor in six patients who died (median 3.3, range 3.3 to 4.3 mins) was significantly greater than in either survivors (median 2.1, range 1.4 to 2.9 mins; p < .001) or the normal group (median 2.5, range 2.2 to 2.8 mins; p < .001). Consistent with theoretical prediction, a significant linear relationship existed between platelet-activating factor half-life and the reciprocal of acetylhydrolase activity in the patient group (p < .05). Plasma phospholipase A2 activity was markedly increased in the patient group, while plasma lyso-platelet-activating factor and serum lipid concentrations were severely decreased. ConclusionsDepression of acetylhydrolase activity was consistent with the concentration of lipids with which it is associated. Platelet-activating factor half-life was relatively well preserved because of the nature of its relationship with enzyme activity. The half-life was prolonged in those patients with the worst outcome and the breakdown in plasma degradation of platelet-activating factor could have contributed to pathophysiology in these subjects. (Crit Care Med 1994; 22:204–212)

Variation in plasma platelet-activating factor degradation and serum lipids after acute myocardial infarction

BackgroundPlatelet-activating factor is a biologically potent phospholipid that may mediate cell damage in patients with myocardial ischemia. In plasma, its inactivation to lyso-platelet-activating factor is catalyzed by a specific, lipoprotein-associated acetylhydrolase. Because lipoprotein levels decrease after myocardial infarction, a possible reduction was suspected to occur in plasma degradation of platelet-activating factor. MethodsDegradation of platelet-activating factor was examined in an optimized assay of acetylhydrolase activity and in relation to the in vitro plasma half-life of platelet-activating factor. These, plasma lyso-platelet-activating factor and serum lipids, were measured in 12 men with acute myocardial infarction at presentation and at 2 and 7 days later. ResultsAcetylhydrolase activity was depressed at day 2 and at day 7. The corresponding increase in plasma half-life of platelet-activating factor was minimal and insignificant. A significant linear relation existed between the half-life of platelet-activating factor and the reciprocal of acetylhydrolase activity at each time of study, indicating a hyperbolic relation between the two. By day 2, total and low-density lipoprotein cholesterol had decreased but showed no further change by day 7; high-density lipoprotein cholesterol had not decreased at day 2 but was depressed by day 7. Plasma lyso-platelet-activating factor had decreased by day 2 and had returned to its initial level by day 7. ConclusionsAcute myocardial infarction is associated with depression of plasma acetylhydrolase activity, and because of the hyperbolic relation between the plasma enzyme activity and the half-life of platelet-activating factor, the latter shows negligible change. Hence, the mechanism for the inactivation of any platelet-activating factor that might be released as a consequence of tissue damage is preserved.

WHOLE BLOOD PLATELET AGGREGATION IS NOT AFFECTED BY CIGARETTE SMOKING BUT IS SEX‐RELATED

1. In normal subjects, 18–49 years old, the effects of the smoking habit (>10 cigarettes/day) and the act of smoking two cigarettes over 10 min were studied on whole blood platelet aggregation (in vitro impedance method).

Adult human mesenchymal stromal cells and the treatment of graft versus host disease

Graft versus host disease is a difficult and potentially lethal complication of hematopoietic stem cell transplantation. It occurs with minor human leucocyte antigen (HLA) mismatch and is normally treated with corticosteroid and other immunosuppressive therapy. When it is refractory to steroid therapy, mortality approaches 80%. Mesenchymal stromal cells are rare cells found in bone marrow and other tissues. They can be expanded in culture and possess complex and diverse immunomodulatory activity. Moreover, human mesenchymal stromal cells carry low levels of class 1 and no class 2 HLA antigens, making them immunoprivileged and able to be used without HLA matching. Their use in steroid-refractory graft versus host disease was first described in 2004. Subsequently, they have been used in a number of Phase I and II trials in acute and chronic graft versus host disease trials with success. We discuss their mode of action, the results, their production, and potential dangers with a view to future application.

PLASMA PHOSPHOLIPASE A2 ACTIVITY IN CLINICAL ACUTE MYOCARDIAL INFARCTION

b

Mesenchymal Stromal Cell Therapy for Chronic Lung Allograft Dysfunction: Results of a First‐in‐Man Study

Chronic lung transplant rejection (termed chronic lung allograft dysfunction [CLAD]) is the main impediment to long‐term survival after lung transplantation. Bone marrow‐derived mesenchymal stromal cells (MSCs) represent an attractive cell therapy in inflammatory diseases, including organ rejection, given their relative immune privilege and immunosuppressive and tolerogenic properties. Preclinical studies in models of obliterative bronchiolitis and human trials in graft versus host disease and renal transplantation suggest potential efficacy in CLAD. The purpose of this phase 1, single‐arm study was to explore the feasibility and safety of intravenous delivery of allogeneic MSCs to patients with advanced CLAD. MSCs from unrelated donors were isolated from bone marrow, expanded and cryopreserved in a GMP‐compliant facility. Patients had deteriorating CLAD and were bronchiolitis obliterans (BOS) grade ≥ 2 or grade 1 with risk factors for rapid progression. MSCs (2 x 106 cells per kilogram patient weight) were infused via a peripheral vein twice weekly for 2 weeks, with 52 weeks follow‐up. Ten Patients (5 male, 8 bilateral, median [interquartile range] age 40 [30–59] years, 3 BOS2, 7 BOS3) participated. MSC treatment was well tolerated with all patients receiving the full dosing schedule without any procedure‐related serious adverse events. The rate of decline in forced expiratory volume in one second slowed after the MSC infusions (120 ml/month preinfusion vs. 30 ml/month postinfusion, p = .08). Two patients died at 152 and 270 days post‐MSC treatment, both from progressive CLAD. In conclusion, infusion of allogeneic bone marrow‐derived MSCs is feasible and safe even in patients with advanced CLAD. Stem Cells Translational Medicine 2017;6:1152–1157

The effects of a PAF antagonist on ischemic myocardial damage and arrhythmia in the dog

Myocardial ischemia is associated with accumulation of lyso-phospholipids, including lyso-platelet activating factor, the degradation product and precursor of platelet activating factor. These compounds produce cellular and microvascular damage and, in the myocardium, depression of contractility and arrhythmia. The potent platelet activating factor antagonist, WEB 2086, or placebo, was infused (IV) 10 min before constriction of the proximal left anterior descending coronary artery in open-chest dogs. Two protocols were followed: the dose of WEB 2086 was 0.5 mg/kg in those subjected to 20 min ischemia with 10 min reperfusion (n = 40) and 5 mg/kg preceding 60 min ischemia alone (n = 24). There was no significant difference in the number of ventricular premature complexes between WEB 2086 and placebo treated dogs during either period of ischemia. On reperfusion in those surviving 20 min of ischemia, 5 of the 18 WEB 2086 and 9 of the 18 placebo treated dogs developed ventricular fibrillation (NS). After 60 min of myocardial ischemia, there was no statistical difference in histological changes (nuclear swelling, aggregation of chromatin, myofibrillar separation) between groups. Hence, no substantial effect of relatively large doses of WEB 2086 on ischemia-induced histological change or arrhythmia was found in this preparation.

NEUTROPHIL PLATELET-ACTIVATING FACTOR PRODUCTION AND ACETYLTRANSFERASE ACTIVITY IN CLINICAL ACUTE MYOCARDIAL INFARCTION

1. Neutrophil function was studied in 10 males presenting with acute myocardial infarction (MI) within 6 h of onset and in 10 normal males. Neutrophil production of platelet‐activating factor (PAF), determined by bioassay, that of leukotriene B4 by HPLC, and the activity of an enzyme involved in the synthesis of PAF, acetyltransferase (AT), were measured before and after stimulation with opsonized zymosan and calcium ionophore, A23187.

Whole blood aggregation and plasma lyso-PAF related to smoking and atherosclerosis

1. Aggregation of diluted whole blood (impedance method) and thromboxane B2 production during aggregation were measured in cigarette smokers and non‐smokers, aged 41–68 years, with (n= 14) and without (n= 15) major symptomatic peripheral vascular disease. The plasma level of the lyso derivative of platelet activating factor (lyso‐PAF) was also measured using a bioassay with 14C‐serotonin labelled rabbit platelets, after extraction and acetylation to active PAF.