Social support as a moderator of healthcare adherence and distress in long-term hematopoietic cell transplantation survivors.

BACKGROUND: Treatment with hematopoietic cell transplantation (HCT) has potentially severe effects on physical and psychosocial functioning. Poor social support has been linked with physical morbidity and mortality as well as psychological distress in HCT survivors. This study tested a theory-driven hypothesis that social support buffers adverse effects of health stressors of comorbidities and graft-versus-host disease (cGVHD) on distress and adherence to recommended healthcare among long-term HCT survivors. METHODS: This cross-sectional study analyzed baseline data from a randomized controlled trial in adult survivors 3-18 years post-HCT. Data included medical records and patient-reported outcomes including cancer and treatment distress (CTXD), healthcare adherence (HCA), comorbidity index, cGVHD, ENRICHD Social Support Instrument (ESSI), Social Activity Log, and Health Self-Efficacy. We tested hypothesized models for HCA and CTXD using blocked hierarchical linear regressions. RESULTS: Among the 781 HCT survivors completing baseline assessment, 38% had > 3 comorbidities, 8% had moderate-severe cGVHD, 30% reported low social support, 30% reported elevated distress, and 49% reported low healthcare adherence. Social support and self-efficacy were directly related to both adherence and distress. Regression models supported the hypothesized moderated relationships for distress but not for healthcare adherence. CONCLUSIONS: The two tested models confirm that the health stressors of comorbidities and cGVHD are moderated by better social support and self-efficacy in their associations with lower distress but without moderating effects for healthcare adherence. IMPLICATIONS FOR CANCER SURVIVORS: Social support and self-efficacy confer protective benefits on healthcare adherence and psychological distress. Interventions are needed that focus on maintaining social networks or finding new networks if necessary. CLINICAL TRIAL REGISTRATION NUMBER: NCT00799461.

Factors associated with social functioning among long-term cancer survivors treated with hematopoietic stem cell transplantation as adolescents or young adults.

OBJECTIVE: Hematopoietic stem cell transplantation (HSCT) can compromise long-term health and social functioning. We examined the impact of physical and social-emotional factors on the social functioning of long-term adolescent and young adult (AYA) HSCT survivors. METHODS: This cross-sectional analysis included HSCT recipients from the INSPIRE trial [NCT00799461] who received their first transplant between ages 15-39. Patient-reported outcome measures included the Short Form-36v2, Fatigue Symptom Inventory, Cancer and Treatment Distress, and the ENRICHD Social Support Inventory. We used hierarchical multiple linear regression to identify physical and social-emotional factors associated with social functioning at the baseline assessment, with the first block including sociodemographic and clinical factors significant at P = <0.10 in univariate testing, the second block including fatigue and physical function, and the third block including social support and distress. RESULTS: Participants (N = 279) were 52% male and 93.5% white, non-Hispanic, with a mean age of 30.3 (SD 6.6) at first transplant. Social Functioning mean was 48.5 (SD 10.5), below age-adjusted norms (t = -13.6, P = <0.001). In the first block, current chronic graft-vs-host disease accounted for 5.5% of the variance (P = <0.001). Adding fatigue and physical function explained an additional 46.6% of the variance (P = <0.001). Adding distress and social support explained an additional 7.7% of the variance (P = <0.001). The final model explained 59.8% of the variance; distress, fatigue, and physical function were significantly associated with social functioning. CONCLUSIONS: Distress, fatigue, and physical function are associated with social functioning and interventions targeting these symptoms may help to improve SF among long-term cancer survivors treated with HSCT as AYAs.

An online randomized controlled trial, with or without problem-solving treatment, for long-term cancer survivors after hematopoietic cell transplantation.

PURPOSE: This randomized controlled trial examines the efficacy of INSPIRE, an INternet-based Survivorship Program with Information and REsources, with or without problem-solving treatment (PST) telehealth calls, for survivors after hematopoietic cell transplantation (HCT). METHODS: All adult survivors who met eligibility criteria were approached for consent. Participants completed patient-reported outcomes at baseline and 6 months. Those with baseline impaired scores on one or more of the outcomes were randomized to INSPIRE, INSPIRE + PST, or control with delayed INSPIRE access. Outcomes included Cancer and Treatment Distress, Symptom Checklist-90-R Depression, and Fatigue Symptom Inventory. Planned analyses compared arms for mean change in aggregated impaired outcomes and for proportion of participants improved on each outcome. RESULTS: Of 1306 eligible HCT recipients, 755 (58%) participated, and 344 (45%) had one or more impaired scores at baseline. We found no reduction in aggregated outcomes for either intervention (P > 0.3). In analyses of individual outcomes, participants randomized to INSPIRE + PST were more likely to improve in distress than controls (45 vs. 20%, RR 2.3, CI 1.0, 5.1); those randomized to INSPIRE alone were marginally more likely to improve in distress (40 vs. 20%, RR 2.0, CI 0.9, 4.5). CONCLUSIONS: The INSPIRE online intervention demonstrated a marginal benefit for distress that improved with the addition of telehealth PST, particularly for those who viewed the website or were age 40 or older. IMPLICATIONS FOR CANCER SURVIVORS: Online and telehealth programs such as INSPIRE offer opportunities to enhance HCT survivorship outcomes, particularly for mood, though methods would benefit from strategies to improve efficacy.

Engagement with INSPIRE, an Online Program for Hematopoietic Cell Transplantation Survivors.

In a secondary analysis of a randomized controlled trial (RCT), we examined participants' engagement with INSPIRE, a personalized online program for hematopoietic cell transplantation (HCT) survivors that focuses on cancer-related distress, depression, fatigue, and health care needs. We approached all adult, 3- to 18-year HCT survivors treated for hematologic malignancy without relapse or second cancer in the previous 2 years for participation in an RCT with either immediate or delayed access to INSPIRE. Participants with immediate access could view the online material at any time. Data included page view tracking, medical records, and patient-reported outcomes, including the Short Form 36 and Cancer and Treatment Distress (CTXD) measures. Of 1322 eligible HCT survivors, 771 (58%) completed the baseline assessment, and 451 received immediate INSPIRE access and were included in analyses. The cohort was 56% male, with a mean age of 52 ± 12.2 years, and 26% received an autologous transplant. Most (77%) logged into the INSPIRE site at least once, and 48% viewed ≥8 pages. Survivors who viewed ≥2 pages were more likely to be age ≥40 years (relative risk [RR], 1.41; 95% confidence interval [CI], 1.10 to 1.80), to be female (RR, 1.22; 95% CI, 1.07 to 1.40), to have chronic graft-versus-host disease (RR, 1.28; 95% CI, 1.08 to 1.51), to be less than 10 years post-HCT (RR, 1.19; 95% CI, 1.01 to 1.39), and to have moderate CTXD distress (RR, 1.34; 95% CI, 1.14 to 1.57). Engagement did not differ by race, education, income, rural/urban residence, computer experience, donor type, or depression (all P ≥ .50). The INSPIRE online program was widely used, including by those who often have reduced access to care after treatment.

Cyclophosphamide leads to persistent deficits in physical performance and in vivo mitochondria function in a mouse model of chemotherapy late effects.

Fatigue is the symptom most commonly reported by long-term cancer survivors and is increasingly recognized as related to skeletal muscle dysfunction. Traditional chemotherapeutic agents can cause acute toxicities including cardiac and skeletal myopathies. To investigate the mechanism by which chemotherapy may lead to persistent skeletal muscle dysfunction, mature adult mice were injected with a single cyclophosphamide dose and evaluated for 6 weeks. We found that exposed mice developed a persistent decrease in treadmill running time compared to baseline (25.7±10.6 vs. 49.0±16.8 min, P = 0.0012). Further, 6 weeks after drug exposure, in vivo parameters of mitochondrial function remained below baseline including maximum ATP production (482.1 ± 48.6 vs. 696.2 ± 76.6, P = 0.029) and phosphocreatine to ATP ratio (3.243 ± 0.1 vs. 3.878 ± 0.1, P = 0.004). Immunoblotting of homogenized muscles from treated animals demonstrated a transient increase in HNE adducts 1 week after exposure that resolved by 6 weeks. However, there was no evidence of an oxidative stress response as measured by quantitation of SOD1, SOD2, and catalase protein levels. Examination of mtDNA demonstrated that the mutation frequency remained comparable between control and treated groups. Interestingly, there was evidence of a transient increase in NF-ĸB p65 protein 1 day after drug exposure as compared to saline controls (0.091±0.017 vs. 0.053±0.022, P = 0.033). These data suggest that continued impairment in muscle and mitochondria function in cyclophosphamide-treated animals is not linked to persistent oxidative stress and that alternative mechanisms need to be considered.

Establishment and validation of a 384-well antibacterial assay amenable for high-throughput screening and combination testing.

A 384-well-based antibacterial assay amenable for high-throughput screening and combination testing is described. The assay uses 100-500nL of test compounds and tolerates up to 2.5% dimethyl sulfoxide concentrations. It can be used for screening compound libraries and testing combinatory/synergistic/antagonistic effects of antibiotics, small molecules, and natural product extracts.

Iron and citrate export by a major facilitator superfamily pump regulates metabolism and stress resistance in Salmonella Typhimurium.

The efficacy of antibiotics and host defenses has been linked to the metabolic and redox states of bacteria. In this study we report that a stress-induced export pump belonging to the major facilitator superfamily effluxes citrate and iron from the enteric pathogen Salmonella Typhimurium to arrest growth and ameliorate the effects of antibiotics, hydrogen peroxide, and nitric oxide. The transporter, formerly known as MdtD, is now designated IceT (iron citrate efflux transporter). Iron efflux via an iron-chelating tricarboxylic acid cycle intermediate provides a direct link between aerobic metabolism and bacterial stress responses, representing a unique mechanism of resistance to host defenses and antimicrobial agents of diverse classes.

Isolation and characterization of antimicrobial compounds in plant extracts against multidrug-resistant Acinetobacter baumannii.

The number of fully active antibiotic options that treat nosocomial infections due to multidrug-resistant Acinetobacter baumannii (A. baumannii) is extremely limited. Magnolia officinalis, Mahonia bealei, Rabdosia rubescens, Rosa rugosa, Rubus chingii, Scutellaria baicalensis, and Terminalia chebula plant extracts were previously shown to have growth inhibitory activity against a multidrug-resistant clinical strain of A. baumannii. In this study, the compounds responsible for their antimicrobial activity were identified by fractionating each plant extract using high performance liquid chromatography, and determining the antimicrobial activity of each fraction against A. baumannii. The chemical structures of the fractions inhibiting >40% of the bacterial growth were elucidated by liquid chromatography/mass spectrometry analysis and nuclear magnetic resonance spectroscopy. The six most active compounds were identified as: ellagic acid in Rosa rugosa; norwogonin in Scutellaria baicalensis; and chebulagic acid, chebulinic acid, corilagin, and terchebulin in Terminalia chebula. The most potent compound was identified as norwogonin with a minimum inhibitory concentration of 128 µg/mL, and minimum bactericidal concentration of 256 µg/mL against clinically relevant strains of A. baumannii. Combination studies of norwogonin with ten anti-Gram negative bacterial agents demonstrated that norwogonin did not enhance the antimicrobial activity of the synthetic antibiotics chosen for this study. In conclusion, of all identified antimicrobial compounds, norwogonin was the most potent against multidrug-resistant A. baumannii strains. Further studies are warranted to ascertain the prophylactic and therapeutic potential of norwogonin for infections due to multidrug-resistant A. baumannii.

The phage shock protein PspA facilitates divalent metal transport and is required for virulence of Salmonella enterica sv. Typhimurium.

The phage shock protein (Psp) system is induced by extracytoplasmic stress and thought to be important for the maintenance of proton motive force. We investigated the contribution of PspA to Salmonella virulence. A pspA deletion mutation significantly attenuates the virulence of Salmonella enterica serovar Typhimurium following intraperitoneal inoculation of C3H/HeN (Ity(r) ) mice. PspA was found to be specifically required for virulence in mice expressing the natural resistance-associated macrophage protein 1 (Nramp1) (Slc11a1) divalent metal transporter, which restricts microbial growth by limiting the availability of essential divalent metals within the phagosome. Salmonella competes with Nramp1 by expressing multiple metal uptake systems including the Nramp-homologue MntH, the ABC transporter SitABCD and the ZIP family transporter ZupT. PspA was found to facilitate Mn(2+) transport by MntH and SitABCD, as well as Zn(2+) and Mn(2+) transport by ZupT. In vitro uptake of (54) Mn(2+) by MntH and ZupT was reduced in the absence of PspA. Transport-deficient mutants exhibit reduced viability in the absence of PspA when grown under metal-limited conditions. Moreover, the ZupT transporter is required for Salmonella enterica serovar Typhimurium virulence in Nramp1-expressing mice. We propose that PspA promotes Salmonella virulence by maintaining proton motive force, which is required for the function of multiple transporters mediating bacterial divalent metal acquisition during infection.

Absence of functional Hfe protects mice from invasive Salmonella enterica serovar Typhimurium infection via induction of lipocalin-2.

Mutations of HFE are associated with hereditary hemochromatosis, but their influence on host susceptibility to infection is incompletely understood. We report that mice lacking one or both Hfe alleles are protected from septicemia with Salmonella Typhimurium, displaying prolonged survival and improved control of bacterial replication. This increased resistance is paralleled by an enhanced production of the enterochelin-binding peptide lipocalin-2 (Lcn2), which reduces the availability of iron for Salmonella within Hfe-deficient macrophages. Accordingly, Hfe(-/-)Lcn2(-/-) macrophages are unable to efficiently control the infection or to withhold iron from intracellular Salmonella. Correspondingly, the protection conferred by the Hfe defect is abolished in Hfe(-/-) mice infected with enterochelin-deficient Salmonella as well as in Hfe(-/-)Lcn2(-/-) mice infected with wild-type bacteria. Thus, by induction of the iron-capturing peptide Lcn2, absence of functional Hfe confers host resistance to systemic infection with Salmonella, thereby providing an evolutionary advantage which may account for the high prevalence of genetic hemochromatosis.

Slc11a1 limits intracellular growth of Salmonella enterica sv. Typhimurium by promoting macrophage immune effector functions and impairing bacterial iron acquisition.

The natural resistance-associated macrophage protein 1, Slc11a1, is a phagolysosomal transporter for protons and divalent ions including iron that confers host protection against diverse intracellular pathogens including Salmonella. We investigated and compared the regulation of iron homeostasis and immune function in RAW264.7 murine phagocytes stably transfected with non-functional Slc11a1 and functional Slc11a1 controls in response to an infection with Salmonella enterica serovar Typhimurium. We report that macrophages lacking functional Slc11a1 displayed an increased expression of transferrin receptor 1, resulting in enhanced acquisition of transferrin-bound iron. In contrast, cellular iron release mediated via ferroportin 1 was significantly lower in Salmonella-infected Slc11a1-negative macrophages in comparison with phagocytes bearing Slc11a1. Lack of Slc11a1 led to intracellular persistence of S. enterica serovar Typhimurium within macrophages, which was paralleled by a reduced formation of nitric oxide, tumour necrosis factor-alpha and interleukin-6 in Slc11a1-negative macrophages following Salmonella infection, whereas interleukin-10 production was increased. Moreover, Slc11a1-negative phagocytes exhibited higher cellular iron content, resulting in increased iron acquisition by intracellular Salmonella. Our observations indicate a bifunctional role for Slc11a1 within phagocytes. Slc11a restricts iron availability, which first augments pro-inflammatory macrophage effector functions and second concomitantly limits microbial iron access.

Biosynthesis and IroC-dependent export of the siderophore salmochelin are essential for virulence of Salmonella enterica serovar Typhimurium.

In response to iron deprivation, Salmonella enterica serovar Typhimurium secretes two catecholate-type siderophores, enterobactin and its glucosylated derivative salmochelin. Although the systems responsible for enterobactin synthesis and acquisition are well characterized, the mechanisms of salmochelin secretion and acquisition, as well as its role in Salmonella virulence, are incompletely understood. Herein we show by liquid chromatography-mass spectrometry analysis of culture supernatants from wild type and isogenic mutant bacterial strains that the Major Facilitator Superfamily pump EntS is the major exporter of enterobactin and the ABC transporter IroC exports both salmochelin and enterobactin. Growth promotion experiments demonstrate that IroC is not required for utilization of Fe-enterobactin or Fe-salmochelin, as had been previously suggested, but the ABC transporter protein FepD is required for utilization of both siderophores. Salmonella mutants deficient in salmochelin synthesis or secretion exhibit reduced virulence during systemic infection of mice.

Maintenance of nitric oxide and redox homeostasis by the salmonella flavohemoglobin hmp.

Intracellular pathogens must resist the antimicrobial actions of nitric oxide (NO.) produced by host cells. To this end pathogens possess several NO.-metabolizing enzymes. Here we show that the flavohemoglobin Hmp is the principal enzyme responsible for aerobic NO. metabolism by Salmonella enterica serovar typhimurium. We further show that Hmp is required for Salmonella virulence in mice, in contrast to S-nitrosoglutathione reductase, flavorubredoxin, or cytochrome c nitrite reductase. Abrogation of murine-inducible NO. synthase restores virulence to hmp mutant bacteria. In the presence of nitrosative stress, Hmp-deficient Salmonella exhibits reduced NO. consumption, impaired growth, increased protein S-nitrosylation, and filamentous morphology. However, under aerobic conditions in the absence of nitrosative stress, elevated hmp expression increases S. typhimurium susceptibility to hydrogen peroxide. Both the heme binding and flavoreductase domains are required for resistance to NO., whereas the flavoreductase domain is responsible for iron-dependent susceptibility to oxidative stress. This provides a rationale for the regulation of hmp expression by the transcriptional repressor NsrR in response to both nitrosative stress and intracellular free iron concentration. The Hmp flavohemoglobin plays a central role in the response of Salmonella to nitrosative stress but requires precise regulation to avoid the exacerbation of oxidative stress that can result if electrons are shuttled to extraneous iron.

Characterization of six lipoproteins in the sigmaE regulon.

In Escherichia coli, sigma(E) regulon functions are required for envelope homeostasis during stress and are essential for viability under all growth conditions. The E. coli genome encodes approximately 100 lipoproteins, and 6 of these are regulated by sigma(E). Phenotypes associated with deletion of each of these lipoproteins are the subject of this report. One lipoprotein, YfiO, is essential for cellular viability. However, overexpression of this protein is not sufficient to alleviate the requirement of sigma(E) for viability, suggesting that the sigma(E) regulon provides more than one essential function. The remaining five lipoproteins in the sigma(E) regulon are nonessential; cells are viable even when all five are removed simultaneously. Deletion of three nonessential lipoprotein genes (nlpB, yraP, ygfL) results in the exhibition of phenotypes that suggest they are important for maintenance of the integrity of the cell envelope. deltanlpB cells are selectively sensitive to rifampin; deltayraP cells are selectively sensitive to sodium dodecyl sulfate. Such selective sensitivity has not been previously reported. Both deltayraP and deltanlpB are synthetically lethal with surA::Cm, which encodes a periplasmic chaperone and PPIase, suggesting that NlpB and YraP play roles in a periplasmic folding pathway that functions in parallel with that of SurA. Finally, the deltayfgL mutant exhibits a broad range of envelope defects, including sensitivity to several membrane-impermeable agents, an altered outer membrane protein profile, synthetic lethality with both surA::Cm and deltafkpA::Cm strains, and sensitivity to a bactericidal permeability-increasing peptide. We suggest that this lipoprotein performs a very important but as-yet-unknown function in maintaining the integrity of the cell envelope.

The alternative sigma factor sigma is required for resistance of Salmonella enterica serovar Typhimurium to anti-microbial peptides.

The enteric pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium) encounters a variety of anti-microbial peptides during the course of infection. We report here that the extracytoplasmic sigma factor sigma(E) (RpoE) is required for Salmonella resistance to killing by the bactericidal/permeability-increasing protein (BPI)-derived peptide P2 and the murine alpha-defensin cryptdin-4 (Crp4). Moreover, sigma(E)-deficient S. Typhimurium is attenuated for virulence after oral infection of immunocompromised gp91phox(-/-) mice that lack a functional NADPH phagocyte oxidase, suggesting that sigma(E) plays an important role in resistance to non-oxidative mucosal host defences such as anti-microbial peptides. Although both P2 and Crp4 target the cell envelope, bacterial killing by these peptides appears to occur by distinct mechanisms. Formate enhances bacterial resistance to P2, as previously demonstrated, but not to Crp4. Both sigma(E) and cytoplasmic membrane-associated formate dehydrogenase are required for the protective effect of formate against P2. In contrast to P2, Crp4 does not inhibit bacterial respiration at lethal concentrations. However, both peptides induce expression of rpoE, suggesting that they trigger a common mechanism for sensing extracytoplasmic stress.

Compensatory role of PspA, a member of the phage shock protein operon, in rpoE mutant Salmonella enterica serovar Typhimurium.

Sigma(E) is an alternative sigma factor that responds to and ameliorates extracytoplasmic stress. In Salmonella enterica serovar Typhimurium (S. Typhimurium), sigma(E) is required for oxidative stress resistance, stationary-phase survival and virulence in mice. Microarray analysis of stationary-phase gene expression in rpoE mutant bacteria revealed a dramatic increase in expression of pspA, a member of the phage shock protein (psp) operon. The psp operon can be induced by filamentous bacteriophages or by perturbations of protein secretion, and is believed to facilitate the maintenance of proton motive force (PMF). We hypothesized that increased pspA expression may represent a compensatory response to the loss of sigma(E) function. Increased pspA expression was confirmed in rpoE mutant Salmonella and also observed in a mutant lacking the F(1)F(0) ATPase. Alternatively, expression of pspA could be induced by exposure to CCCP, a protonophore that disrupts PMF. An rpoE pspA double mutant strain was found to have a stationary-phase survival defect more pronounced than that of isogenic strains harbouring single mutations. The double mutant strains were also more susceptible to killing by CCCP or by a bactericidal/permeability-increasing protein (BPI)-derived anti-microbial peptide. Using fluorescence ratio imaging, differences were observed in the Deltapsi of wild-type and rpoE or pspA mutant bacteria. These findings suggest that pspA expression in S. Typhimurium is induced by alterations in PMF and a functional sigma(E) regulon is essential for the maintenance of PMF.