Inhibition of platelet function by cis-unsaturated fatty acids

The uptake of free fatty acids has previously been shown to affect the capping of lymphocytes, and there is evidence that different types of fatty acids may partition into separate lipid domains in cell surface membranes. In studies of gel-filtered human platelets, we found that cis-unsaturated fatty acids (1-35 microM) inhibited platelet shape change, aggregation, and secretion of 5-hydroxytryptamine induced by thrombin, adenosine diphosphate (ADP), collagen, U46619 (a thromboxane A2 analog), or plant lectins, but not that induced by A23187, a calcium ionophore. Trans-unsaturated and saturated fatty acids had little or no inhibitory effect. The inhibitory effects of cis-unsaturated fatty acids were not affected by inhibition of adenylate cyclase or cyclooxygenase. 14C-labeled fatty acids were taken up into platelet lipids. The maximum platelet-inhibitory effect of cis-unsaturated fatty acids was seen when over 90% of the platelet label was still in the form of free fatty acids. Platelet inhibition could be reversed by washing the platelets by gel filtration. Binding of platelet agonists to the platelet was not inhibited by the fatty acids. Cis-unsaturated fatty acids, but not trans-unsaturated or saturated fatty acids, decreased fluorescence polarization of platelets or isolated platelet membranes monitored with 1,6-diphenyl- 1,3,5-hexatriene. The potency of the fatty acids as inhibitors of platelet aggregation was inversely correlated with their melting points. These data suggest that inhibition of receptor-mediated platelet responses by cis-unsaturated fatty acids results from perturbation of the platelet membrane in specific lipid domains.     

Recent advances in glucose-lowering treatment to reduce diabetic kidney disease

Introduction: The epidemic of diabetes has now taken on epic proportions and therefore reducing the impact of diabetic complications represents one of the major global challenges in improving health and well-being worldwide. Preventing the development of diabetic kidney disease (DKD) is particularly important, as diabetes is one of the main risk factors for the development of chronic kidney disease, which in turn is strongly linked to development of cardiovascular disease, end-stage renal failure, hospitalization and premature death. Intensive glucose-lowering treatment has been shown to prevent and slow progression of DKD, yet to date, only certain populations have benefited from this intervention.

Areas covered: We review the evidence for existing glucose-lowering treatments in the prevention of DKD, and research into techniques to better target individuals who will benefit from these therapies.

Expert opinion: Diabetic patients with established kidney disease may benefit from glucose-lowering treatment, particularly if a safer side-effect profile of these treatments is achieved. Better understanding of glucose homeostasis and evaluation of compounds inhibiting its downstream effects are required in order to improve the outlook for individuals with DKD. An additional approach to improve the success rate of glucose-lowering treatment is to improve the selection of individuals who may benefit from treatment. A potential means to identify such subjects could involve the use of biomarkers.     

Simultaneous Klebsiella pneumoniae and amoebic liver abscess in an immunocompetent patient

Simultaneous Klebsiella pneumoniae and amoebic liver abscess is rarely reported in immunocompetent patients. A 47-year-old man was hospitalized with abdominal pain, fever, chills, and hypotension. Physical examination revealed right upper quadrant tenderness. Abdominal computed tomography showed an area of low attenuation with some liquefaction in the liver. Echo-guided aspiration revealed 30 mL of pus, which grew Klebsiella pneumoniae, and the same organism was isolated from the blood. Cytology examination of the pus showed scattered amoeba. The patient gradually improved over 1 month on treatment with cefmetazole and metronidazole, along with repeated drainage of the abscess. His amoebic indirect hemagglutination titer was 1:128, but no parasite ova or amoeba were found in the stool. He had no evidence of immunocompromise. Parasitic diseases may be a predisposing factor for bacterial infections, including pyogenic liver abscess. The possible coexistence of amoebae and bacteria in a liver abscess should not be discounted.     

Fate of the DNA in plasmid-containing Escherichia coli minicells ingested by human neutrophils

Escherichia coli minicells containing the plasmid pSC101 (approximately 10 kb) or pBR322 (approximately 4 kb) were opsonized and incubated with human neutrophils. The neutrophils responded to the minicells as they would to native E coli: they ingested the minicells, discharged their granule contents into the minicell-containing phagosomes, and expressed a respiratory burst. After one hour of incubation, the fate of the ingested plasmid DNA was examined. No DNA degradation was detected by trichloroacetic acid precipitation or agarose gel electrophoresis. Moreover, when pBR322 recovered from ingested minicells was transformed into E coli, no mutations in either of the antibiotic resistance genes carried by the plasmid were detected out of many thousand transformants screened. These findings confirm the surprisingly limited effect of neutrophils on ingested DNA.     

Induction of tolerance in nondefective mice after in utero transplantation of major histocompatibility complex-mismatched fetal hematopoietic stem cells

Significant morbidity and mortality are associated with the conditioning therapy needed for postnatal bone marrow transplantation (BMT) for inherited diseases. This could be eliminated with hematopoietic stem cell (HSC) transplantation in utero, when the immunoincompetence of the fetus permits engraftment without the need for immunosuppressive therapy. We have established an in utero (day 11 to day 13) model of HSC transplantation in nondefective, allogeneic major histocompatibility complex (MHC)-mismatched mice. Donor cells wre from pooled fetal livers of C57BL/6 (H-2b, GPI-1b) mice. Engraftment was tested by quantitative polymerase chain reaction (PCR) for the Y chromosome in female recipients (with 0.00001% sensitivity). Eight percent (3 of 36) of allogeneic mismatched (Balb-c, H-2d) recipients and 25% (3 of 12) of congenic (C57B1/6, GPI-1a) recipients showed durable engraftment (male donor cells detected beyond 20 weeks of age) based on analysis of peripheral blood leukocytes (P > .08). When spleen and liver were analyzed, 51% (17 of 33) of allogeneic recipients and 50% (6 of 12) of congenic recipients showed durable engraftment (P > .3). The percent donor cells that durably engrafted varied from as low as 0.0001% in spleen and liver to as high as 0.6% in peripheral blood. Postnatal boosting with a single dose of allogeneic MHC-mismatched donor cells in a tolerant, engrafted mouse resulted in a significant increase in donor cells in the peripheral blood from 0.2% pre-boost to 5% 6 months after the boost. There was no evidence of engraftment in nontolerant mice after the postnatal boost with a similar dose of donor cells. Twenty-two allogeneic recipients were evaluated for donor skin graft acceptance at 6 to 12 months of age. Three mice with engraftment in blood and/or tissue permanently accepted donor skin grafts, one of them with donor cells detectable only in the liver. Six additional mice that showed prolonged skin graft acceptance had no evidence of durable engraftment in the blood but were engrafted in the liver and/or spleen. The degree of engraftment in tolerant mice was low (< or = 0.1% donor cells). We conclude that at an early gestational age in nondefective mice (1) high rates of durable engraftment are achievable, although the degree of engraftment is usually low (less than 1%); (2) the percent of donor cells in the peripheral blood may be increased by a postnatal boost of donor cells in tolerant animals without conditioning therapy; (3) MHC appears to have little influence on engraftment efficiency at an early gestational age; (4) a very small number of circulating donor cells in the blood or the tissues is sufficient for the induction and maintenance of tolerance, and (5) the presence of donor cells in the circulating blood is not necessary for prolonged skin graft acceptance or maintenance of permanent skin graft acceptance.     

Rearrangements of the MLL gene in therapy-related acute myeloid leukemia in patients previously treated with agents targeting DNA- topoisomerase II

Chromosome band 11q23 is frequently involved in acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) de novo, as well as in myelodysplastic syndromes (MDS) and lymphoma. Five percent to 15% of patients treated with chemotherapy for a primary neoplasm develop therapy-related AML (t-AML) that may show rearrangements, usually translocations involving band 11q23 or, less often, 21q22. These leukemias develop after a relatively short latent period and often follow the use of drugs that inhibit the activity of DNA-topoisomerase II (topo II). We previously identified a gene, MLL (myeloid-lymphoid leukemia or mixed-lineage leukemia), at 11q23 that is involved in the de novo leukemias. We have studied 17 patients with t-MDS/t-AML, 12 of whom had cytogenetically detectable 11q23 rearrangements. Ten of the 12 t-AML patients had received topo II inhibitors and 9 of these, all with balanced translocations of 11q23, had MLL rearrangements on Southern blot analysis. None of the patients who had not received topo II inhibitors showed an MLL rearrangement. Of the 5 patients lacking 11q23 rearrangements, some of whom had monoblastic features, none had an MLL rearrangement, although 4 had received topo II inhibitors. Our study indicates that the MLL gene rearrangements are similar both in AML that develops de novo and in t-AML. The association of exposure to topo II- reactive chemotherapy with 11q23 rearrangements involving the MLL gene in t-AML suggests that topo II may play a role in the aberrant recombination events that occur in this region both in AML de novo and in t-AML.     

Interleukin-12 augments cytolytic activity of peripheral blood lymphocytes from patients with hematologic and solid malignancies

Interleukin-12 (IL-12) is a heterodimeric 70-kD cytokine that can enhance the activity of cytotoxic effector cells. Although IL-12 shares some functional properties with interleukin-2 (IL-2), it appears to act via a distinct mechanism. In this report, we examined the effects of IL- 12 on the cytolytic activity and proliferation of peripheral blood mononuclear cells (PBMC) obtained from patients with malignant disease. PBMC from two groups of patients were evaluated. The first group consisted of 12 individuals with metastatic solid tumors. PBMC from these patients demonstrated a marked defect in their ability to lyse natural killer (NK)-sensitive targets (K562) compared with normal volunteers. Overnight incubation with IL-12 (35 pmol/L) corrected this defect. The effect of 35 pmol/L of IL-12 on cytotoxicity was similar to that of 3 nmol/L of IL-2. In contrast, this concentration of IL-12 had little effect on cytolytic activity against an NK-resistant cell line (COLO 205). When IL-12 was added to PBMC obtained from cancer patients who were being treated with low-dose IL-2 in vivo, a dramatic increase in cytolytic activity against both NK-sensitive and -resistant tumor targets was observed. Unlike IL-2, IL-12 failed to stimulate proliferation of resting PBMC from cancer patients significantly. The second group of patients we studied comprised 13 patients who had recently undergone allogeneic bone marrow transplantation (BMT) for hematologic malignancy. In resting PBMC from these transplant recipients, IL-12 was capable of enhancing cytotoxicity against both NK- sensitive and -resistant tumor targets. Our findings indicate that IL- 12 can restore defective NK activity of PBMC from patients with metastatic cancer, as well as enhance cytolytic function of PBMC from patients after allogeneic BMT. The clinical use of IL-12 as an immunomodulator in patients with malignancy merits further consideration.     

Peer Support for Self-Management of Chronic Pain: the Evaluation of a Peer Coach-Led Intervention to Improve Pain Symptoms (ECLIPSE) Trial

BackgroundPain self-management is an effective, evidence-based treatment for chronic pain. Peer support, in which patients serve as coaches for other patients, has been effective in other chronic conditions and is a potentially promising approach to implementing pain self-management programs using fewer clinical resources.ObjectiveTo test a peer coach-delivered pain self-management program for chronic pain.DesignRandomized controlled trial.ParticipantsVeterans with chronic musculoskeletal pain.InterventionIntervention patients were assigned a trained peer coach for 6 months. Coaches, who were volunteers, were asked to contact their assigned patients, either by phone or in person, twice per month. Coaches and patients were given an intervention manual to guide sessions. The control group was offered a 2-hour pain self-management class.Main MeasuresThe primary outcome was total pain, assessed by the Brief Pain Inventory (BPI). Secondary outcomes were anxiety, depression, pain catastrophizing, self-efficacy, social support, patient activation, health-related quality of life, and healthcare utilization. Outcomes were measured at baseline, 6 months, and 9 months.Key ResultsTwo hundred fifteen patients enrolled (120 intervention, 95 control). Adherence to intervention protocol was low, with only 13% of patients reporting having at least the recommended 12 peer coach meetings over the 6-month intervention. BPI total decreased from baseline to 6 months and baseline to 9 months in both groups. At 9 months, this change was statistically significant (intervention, − 0.40, p = 0.018; control, − 0.47, p = 0.006). There was not a statistically significant difference between groups on BPI at either time point. No secondary outcomes improved significantly in either group after adjusting for multiple comparisons.ConclusionsPatients randomized to peer support did not differ from control patients on primary and secondary outcomes. Other peer support models that do not rely on volunteers might be more effective.Trial RegistrationClinicalTrials.gov Identifier: {"type":"clinical-trial","attrs":{"text":"NCT02380690","term_id":"NCT02380690"}}NCT02380690Electronic supplementary materialThe online version of this article (10.1007/s11606-020-06007-6) contains supplementary material, which is available to authorized users.KEY WORDS: ECLIPSE, chronic pain, peer support, pain self-management