Couple-based lifestyle intervention to prevent type 2 diabetes: protocol for a randomised pilot trial

INTRODUCTION

Type 2 diabetes is prevalent among US adults. Lifestyle interventions that modify health behaviours prevent or delay progression to diabetes among individuals at high risk. Despite the well-documented influence of individuals' social context on their health, evidence-based type 2 diabetes prevention interventions do not systematically incorporate participants' romantic partners. Involving partners of individuals at high risk for type 2 diabetes in primary prevention may improve engagement and outcomes of programmes. The randomised pilot trial protocol described in this manuscript will evaluate a couple-based lifestyle intervention to prevent type 2 diabetes. The objective of the trial is to describe the feasibility of the couple-based intervention and the study protocol to guide planning of a definitive randomised clinical trial (RCT).

METHODS AND ANALYSIS

We used community-based participatory research principles to adapt an individual diabetes prevention curriculum for delivery to couples. This parallel two-arm pilot study will include 12 romantic couples in which at least one partner (ie, 'target individual') is at risk for type 2 diabetes. Couples will be randomised to either the 2021 version of the CDC's PreventT2 curriculum designed for delivery to individuals (six couples), or PreventT2 Together, the adapted couple-based curriculum (six couples). Participants and interventionists will be unblinded, but research nurses collecting data will be blinded to treatment allocation. Feasibility of the couple-based intervention and the study protocol will be assessed using both quantitative and qualitative measures.

ETHICS AND DISSEMINATION

This study has been approved by the University of Utah IRB (#143079). Findings will be shared with researchers through publications and presentations. We will collaborate with community partners to determine the optimal strategy for communicating findings to community members. Results will inform a subsequent definitive RCT.

TRIAL REGISTRATION NUMBER

NCT05695170.

Impacts of alcohol and opioid polysubstance use on road safety: Systematic review

Connections between substance use, impairment, and road safety have been frequently researched. Yet, little is known about how simultaneous use of opioids and alcohol affects road safety outcomes, which is an increasingly critical link within the current landscape of the substance use environment and public health. Lack of this understanding is partly due to testing complications and data limitations. We define polysubstance use here as alcohol and opioids consumed together or within a small-time window such that both are present in the system. This polysubstance use is on the rise and produces greater health risks than when the substances are consumed separately. Given the increasing rate of opioid use, high prevalence of alcohol use, and dangers of polysubstance use, we aim to synthesize literature on the prevalence and impact of this polysubstance on road safety-related outcomes. We performed a systematic review of studies published between 1974 and 2020 that examined opioid and alcohol use exposures and road safety-related outcomes. Out of 644 initial findings, 20 studies were included in this review. Outcomes included motor vehicle crash injuries, deaths, or driver culpability; suspected driving under the influence; and simulated driving performance. Evidence from multiple sources showed a significant rise, approximately 1% to 7%, in the prevalence of opioids among fatally injured drivers in the U.S. from 1995 to 2016. Information published on the simultaneous presence of opioids and alcohol in people involved in crashes was scarce. The limited available findings point toward an overlap where up to 30% of opioid-positive people involved in a crash were also positive for alcohol. Studies also suggest a possibly elevated risk presented by this polysubstance use relative to the substances used alone, though the majority of identified studies did not estimate this association. The synthesized research indicates that alcohol and opioid use is not uncommon and may be increasing among people involved in adverse driving events. More research and better data are needed to improve estimates of association with road traffic-related outcomes, potentially improving substance testing in current surveillance systems or using linked data sets and other novel data sources to improve estimates.

Reducing opioid use disorder and overdose deaths in the United States: A dynamic modeling analysis

Opioid overdose deaths remain a major public health crisis. We used a system dynamics simulation model of the U.S. opioid-using population age 12 and older to explore the impacts of 11 strategies on the prevalence of opioid use disorder (OUD) and fatal opioid overdoses from 2022 to 2032. These strategies spanned opioid misuse and OUD prevention, buprenorphine capacity, recovery support, and overdose harm reduction. By 2032, three strategies saved the most lives: (i) reducing the risk of opioid overdose involving fentanyl use, which may be achieved through fentanyl-focused harm reduction services; (ii) increasing naloxone distribution to people who use opioids; and (iii) recovery support for people in remission, which reduced deaths by reducing OUD. Increasing buprenorphine providers' capacity to treat more people decreased fatal overdose, but only in the short term. Our analysis provides insight into the kinds of multifaceted approaches needed to save lives.

Economic Evaluation in Opioid Modeling: Systematic Review

OBJECTIVES

The rapid increase in opioid overdose and opioid use disorder (OUD) over the past 20 years is a complex problem associated with significant economic costs for healthcare systems and society. Simulation models have been developed to capture and identify ways to manage this complexity and to evaluate the potential costs of different strategies to reduce overdoses and OUD. A review of simulation-based economic evaluations is warranted to fully characterize this set of literature.

METHODS

A systematic review of simulation-based economic evaluation (SBEE) studies in opioid research was initiated by searches in PubMed, EMBASE, and EbscoHOST. Extraction of a predefined set of items and a quality assessment were performed for each study.

RESULTS

The screening process resulted in 23 SBEE studies ranging by year of publication from 1999 to 2019. Methodological quality of the cost analyses was moderately high. The most frequently evaluated strategies were methadone and buprenorphine maintenance treatments; the only harm reduction strategy explored was naloxone distribution. These strategies were consistently found to be cost-effective, especially naloxone distribution and methadone maintenance. Prevention strategies were limited to abuse-deterrent opioid formulations. Less than half (39%) of analyses adopted a societal perspective in their estimation of costs and effects from an opioid-related intervention. Prevention strategies and studies' accounting for patient and physician preference, changing costs, or result stratification were largely ignored in these SBEEs.

CONCLUSION

The review shows consistently favorable cost analysis findings for naloxone distribution strategies and opioid agonist treatments and identifies major gaps for future research.

Cord blood neutropenia is an independent predictor of early sepsis

OBJECTIVE

The significance of cord blood neutropenia as a screening tool for early-onset sepsis (EOS) is unclear. The objectives were to define reference values for cord blood neutrophil count and to determine the sensitivity and positive likelihood ratio of cord neutropenia for the detection of EOS.

STUDY DESIGN

This retrospective observational cohort study included all mother-infant pairs with deliveries between 2009 and 2014 for whom cord neutrophil counts were routinely done. EOS cases were identified by interrogation of electronic charts. Maternal and perinatal factors were assessed to determine reference values of cord neutrophil. The diagnostic value of neutropenia for detecting EOS was assessed. A nested case-control design was used to measure the value of neutropenia in the detection of EOS in comparison with other risk factors.

RESULTS

A total of 8,590 mother-infant pairs were included. We identified 84 sepsis cases. The neutrophil count was strongly associated with gestational age. Neutropenia adjusted for gestational age was strongly associated with EOS and had good specificity but poor sensitivity. The addition of neutropenia to other EOS risk factors increased sensitivity without decreasing specificity.

CONCLUSION

Cord blood neutropenia was significantly associated with EOS and the addition of cord neutropenia to current EOS risk factors increased the detection rate of EOS.

Evaluation of a Child Safety Program Based on the Safe Community Model in Canada

BACKGROUND: Despite national safety programs, unintentional injuries remain an important health problem in children and adolescents. Cycling, pedestrian and young drivers injuries are particularly influenced by specific community and city aspects. The World Health Organization (WHO) developed community based programs that have been effectively implemented as complements to national safety programs to prevent injuries.

OBJECTIVES: The aim of this study was to evaluate the effectiveness of a local program based on a WHO Safe Community model to reduce cycling, pedestrian and young drivers injuries.

DESIGN/METHODS: A population based quasi-experimental design was used. Pre-implementation and post-implementation data of cycling and pedestrian injury rates (0-15 years) and young drivers injury rates (16-24 years) were collected in the intervention area (Sherbrooke) and in two control communities (Trois-Rivières and Gatineau) in Québec, Canada. RESULTS: Sherbrooke, Gatineau and Trois-Rivières had respectively 69, 82 and 119 cycling and pedestrian injury rate per 100000 children-year in the pre implementation period. Despite its already lower pre-implementation rate, Sherbrooke showed a statistically significant reduction in the post-implementation injury rate compared to Trois-Rivières (Sherbrooke: 49:100000 children-year (OR comparing pre-post rates 0.70 ; 95%CI : 0.45-1.08) and Trois-Rivières 80:100000 children-year (OR comparing pre-post rates 0.68; 95%CI: 0.46-1.0). Gatineau showed a cycling and pedestrian post-implementation injury rate of 63:100000 (OR 0.77; 95%CI: 0.58-1.02). Sherbrooke had the largest young drivers injury reduction with rates of 2912:100000 young driver-year (pre) to 2121: 100000 young driver-year (post) (OR 0.73; 95%CI: 0.66-0.8). Gatineau and Trois-Rivieres showed respectively young drivers injury rate lowering from 2383: 100000 to 2099: 100000 young driver-year (OR 0.88; 95%CI: 0.81-0.95) and from 3447: 100000 to 3295: 100000 young driver-year (OR 0.96; 95%CI 0.87-1.05).

CONCLUSION: Safe Community program established in Sherbrooke was associated with favorable results in injury prevention. Despite its lower pedestrian and cycling injury rate before the intervention, post-implementation injury rate in Sherbrooke was significantly lower compared to Trois-Rivieres. Concerning young drivers injury rates, Sherbrooke showed the biggest reduction, compared to Trois-Riviere and Gatineau. In addition to national injury prevention programs, communities should be encouraged to adopt WHO safe community programs to reduce to a minimum unintentional injury rates in children and adolescents.

Glucocorticoid-induced leucine zipper governs the therapeutic potential of mesenchymal stem cells by inducing a switch from pathogenic to regulatory Th17 cells in a mouse model of collagen-induced arthritis

OBJECTIVE

Mesenchymal stem cells (MSCs) are potent immunosuppressive cells that have shown promise in the treatment of rheumatoid arthritis (RA). Deciphering the intrinsic characteristics of MSCs that correlate with their biologic activity will facilitate their clinical use. Recently, the role of glucocorticoid-induced leucine zipper (GILZ) in the development of RA has been documented. The aim of this study was to evaluate whether GILZ expression by MSCs may contribute to their therapeutic effect.

METHODS

MSCs were isolated from GILZ-deficient (GILZ(-/-) ) mice and wild-type mice. MSCs (1 × 10(6) cells) were injected twice via the tail vein into mice with collagen-induced arthritis (CIA).

RESULTS

In vitro, we showed that GILZ is a key factor involved in the immunosuppressive potential of MSCs. MSCs derived from GILZ(-/-) mice did not suppress the proliferation of CD4+ T cells and were less efficient than MSCs derived from WT mice in altering Th17 cell polarization. Thus, we investigated the role of GILZ in an experimental model of arthritis and demonstrated that although WT MSCs significantly reduced paw swelling in arthritic mice, GILZ(-/-) MSCs did not. Moreover, the magnitude of the effects of GILZ(-/-) MSCs on Th17 cell frequency was significantly lower than that of WT MSCs. The therapeutic effect of MSCs correlated with the generation of Treg cells bearing the CD4 + RORγt+IL-17(low) IL-10+ signature, and Th17 cell polarization was GILZ dependent.

CONCLUSION

This study demonstrates that GILZ has an essential role in the therapeutic effectiveness of MSCs in arthritis by favoring Th17 cell polarization toward a regulatory phenotype. Therefore, potentiation of GILZ expression in MSCs could represent a means to enhance their therapeutic effect in autoimmune diseases.

Chronic agomelatine administration modulates neuronal plasticity markers in the rat prefrontal cortex, hippocampus and amygdala

Neuronal plasticity alterations including cytoskeletal dynamics and synaptic markers have been recently associated with the treatment of major depression. Here we investigated the effects of agomelatine, a novel antidepressant with melatonergic (MT1/MT2) agonist and 5-HT2C receptor antagonist properties, on cytoskeletal microtubular proteins and synaptic markers in the rat hippocampus, prefrontal cortex (PFC) and amygdala.

Adult male Sprague Dawley rats received daily i.p. administration of hydroxyethylcellulose 1% (vehicle) or agomelatine (40mg/kg) for 22 days. The rats were then sacrificed and hippocampi, PFC and amygdala dissected for analyses of microtubule dynamics markers (Tyr/Glu-Tub, Delta2-Tub and Acet-Tub) and synaptic markers (synaptophysin, PSD-95 and spinophilin) by Western blot.

In the PFC, agomelatine decreased Tyr/Glu-Tub and the neuronal-specific Delta2-Tub, suggesting decreased microtubule dynamics. In contrast, in the hippocampus Tyr/Glu-Tub and Delta2-Tub were increased, indicative of enhanced microtubule dynamics. A similar pattern to those seen in the hippocampus, but of higher magnitude, was observed in the amygdala where an important increase of Tyr/Glu-Tub accompanied by a decrease of the stable form Acet-Tub was observed. These findings were paralleled by decreased hippocampal spinophilin (dendritic spines marker), increased synaptophysin (pre-synaptic marker) and spinophilin in the PFC and amygdala and increased PSD-95 (post-synaptic marker) in the amygdala, all consistent with synaptic remodelling phenomena.

Taken together, these data shown that chronic agomelatine induces a differential modulation of microtubule dynamics and synaptic markers in the rat hippocampus, PFC and amygdala. These findings may have a particular relevance considering the fundamental role of these three brain areas in depression.

Identification of a novel cell type-specific intronic enhancer of macrophage migration inhibitory factor (MIF) and its regulation by mithramycin

The aim of this study was to determine the genetic regulation of macrophage migration inhibitory factor (MIF). DNase I hypersensitivity was used to identify potential hypersensitive sites (HS) across the MIF gene locus. Reporter gene assays were performed in different human cell lines with constructs containing the native or mutated HS element. Following phylogenetic and transcription factor binding profiling, electrophoretic mobility shift assay (EMSA) and RNA interference were performed and the effects of incubation with mithramycin, an antibiotic that binds GC boxes, were also studied. An HS centred on the first intron of MIF was identified. The HS acted as an enhancer in human T lymphoblasts (CEMC7A), human embryonic kidney cells (HEK293T) and human monocytic cells (THP-1), but not in a fibroblast-like synoviocyte (FLS) cell line (SW982) or cultured FLS derived from rheumatoid arthritis (RA) patients. Two cis-elements within the first intron were found to be responsible for the enhancer activity. Mutation of the consensus Sp1 GC box on each cis-element abrogated enhancer activity and EMSA indicated Sp1 binding to one of the cis-elements contained in the intron. SiRNA knock-down of Sp1 alone or Sp1 and Sp3 together was incomplete and did not alter the enhancer activity. Mithramycin inhibited expression of MIF in CEMC7A cells. This effect was specific to the intronic enhancer and was not seen on the MIF promoter. These results identify a novel, cell type-specific enhancer of MIF. The enhancer appears to be driven by Sp1 or related Sp family members and is highly sensitive to inhibition via mithramycin.

Partnerships for better oral health

Improving oral health in populations who do not easily access the private dental office or the available community care site is a challenge to dental hygienists and others concerned with the health and well-being of all. Partnerships for improved oral health have been part of the community health efforts for many years and in many countries. With the knowledge, skills, and resources that are held by specific groups and organisations combined into a larger entity of a partnership or coalition, greater impact on oral health issue may be possible. Agencies and individuals interested in making improvements in oral health status in any particular target group may begin a process of working with others who have an interest in improving the health and well being of that target group. In a world that is increasingly synergistic and mutually dependent, improvements in oral health can be advanced by considering the elements of successful coalition building and forming partnerships with multiple organisations and individuals.

Expression of multidrug-resistance P-glycoprotein (MDR1) in human brain tumors

Multidrug resistance (MDR) is associated with the expression of P-glycoprotein (P-gp), an ATP-dependent transporter which expels anti-cancer drugs from cells. In the present study, MDR1 P-gp was immunodetected by Western blot analysis in 60 human brain tumors, including meningiomas, schwannomas, low-grade gliomas (astrocytomas, pilocytic astrocytomas) and high-grade gliomas (anaplastic astrocytomas, glioblastomas and anaplastic oligodendrogliomas). Most samples from primary tumors expressed P-gp at the same levels as normal brain tissue except for schwannomas, in which levels were reduced by 65%, and meningiomas, in which levels were more than 10-fold higher in 7 of 10 samples. P-gp levels were 70% and 95% lower in brain metastases from melanomas and lung adenocarcinomas, respectively, than in normal brain tissue. These results indicate that the majority of primary brain tumors express MDR1 P-gp and that its high expression levels in meningiomas may be a marker for this type of brain tumor.

Better oral health for infants and toddlers: a community based program

Effective partnerships between health professional educational institutions and social service community programs can result in improved health outcomes for the people of the community being served. Such partnerships also may contribute considerably to student maturation into compassionate providers who have an appreciation for how an individual's health and quality of life may be affected by societal factors. A dental hygiene program at a private university and an Early Head Start Program joined in partnership to develop, and implement successfully, a project that was highly productive and of reciprocal benefit. With a focus on infant oral care in general, and early childhood caries in particular, dental hygiene students were able to provide much needed oral health services to 45 families with children enrolled in the Early Head Start Program, at multiple rural locations in Maine. In addition to meeting the needs of the Early Head Start Program, the project created a foundation for student exchange on the issues of dental caries in very young children, and the complexity of the factors contributing to them. Professional dental hygienists may choose to adopt all or portions of this innovative project when planning for the delivery of dental hygiene care to specialized populations in community-based settings.

Dental hygiene public health supervision: changes in Maine law

The author analyzed data from a set of reports submitted to the Maine Board of Dental Examiners by dental hygienists practicing under a new supervision category entitled "Public Health Supervision" enacted in Maine in 1995. The data set included information on public health dental hygiene applicants and projects reported between May 1995 and November 1998. With mounting interest from dental hygienists seeking to serve the population with limited access to preventive dental care, the regulatory board created a public health dental hygiene supervision category in the Maine regulations. The analysis revealed that dental hygienists are seeking and receiving the public health supervision endorsement. Sixty percent of the public health projects were implemented by dental hygienists in public service agencies. Those who addressed a need in their own communities without the benefit of a public health organization accounted for 40% of the applications. Examples of projects are described. The report serves as a summary of three years of data from which to assess future trends.

Matrix proteinase inhibition by AE-941, a multifunctional antiangiogenic compound

BACKGROUND

Matrix metalloproteinases (MMPs) play an important role in tissue remodeling under normal physiological and pathological conditions and are thus attractive targets for both diagnostic and therapeutic purposes. Here, we examined the effect of AE-941, an orally bioavailable standardized extract made of cartilage that shows significant antiangiogenic and antimetastatic properties in vivo, on the activity of various members of the MMP family.

MATERIALS AND METHODS

The effect of AE-941 on the activity of MMPs was assessed by fluorimetric assays and by substrate gel zymography.

RESULTS

AE-941 markedly inhibits the gelatinolytic activity of MMP-2 and to a lesser extent those of MMP-1, MMP-7, MMP-9 and MMP-13. AE-941 also inhibited the elastinolytic activities of MMP-2 and MMP-9 as well as MMP-12 (metalloelastase), porcine pancreatic elastase (PPE), and human leukocyte elastase (HLE). Western blot analysis revealed the presence within AE-941 of immunoreactive TIMP-like proteins, suggesting that these proteins may be at least partly responsible for the observed MMP inhibition.

CONCLUSIONS

Taken together, these results demonstrate that AE-941 contains TIMP-like proteins that could be responsible for the specific inhibition of MMPs. Given the recent studies suggesting the presence within this compound of specific inhibitor(s) of endothelial cell proliferation, AE-941 appears as a pleotropic agent able to interfere with several biochemical steps leading to angiogenesis and to other physiopathological conditions. Since AE-941 is currently under Phase III clinical investigations, these findings are also of considerable importance for our understanding of its anticancer properties.

Expression of matrix metalloproteinases and their inhibitors in human brain tumors

Sixty human brain tumors, classified according to the New World Health Organization (WHO) classification including, grade I schwannomas, meningiomas and pilocytic astrocytomas, grade II astrocytomas, grade III anaplastic astrocytomas, grade IV glioblastomas, grade III anaplastic oligodendrogliomas and grade IV glioblastomas and lung and melanoma metastases were analyzed for the expression of three matrix metalloproteinases (MMPs), two tissue inhibitors of MMPs (TIMPs) and for MMP activity. Some correlation was found between MMP expression and the degree of malignancy. Western blotting analysis revealed a more uniform pattern of distribution of MMP-2 (gelatinase A) than of MMP-9 (gelatinase B) and MMP-12 (metalloelastase) among tumors. MMP-9 levels were found to be significantly higher in grade III anaplastic astrocytomas and anaplastic oligodendrogliomas than those in grade I schwannomas and meningiomas. Anaplastic astrocytomas and Grade IV glioblastomas expressed significantly higher levels MMP-12 than grade I meningiomas. All sixty tumors showed a similar pattern of activity in zymography, proMMP-9 being the major species detected. Interestingly, TIMP-1 and TIMP-2 expression levels were especially low in tumors of grade II and grade III but significantly higher in tumors of grade I, particularly in schwannomas. Taken together, these data suggest that: 1) a balance between MMPs and TIMPs has an important role to play in human brain tumors; 2) TIMP expression may be valuable markers for tumor malignancy.

Expression of matrix metalloproteinases and their inhibitors in human brain tumors

Sixty human brain tumors, classified according to the New World Health Organization (WHO) classification including, grade I schwannomas, meningiomas and pilocytic astrocytomas, grade II astrocytomas, grade III anaplastic astrocytomas, grade IV glioblastomas, grade III anaplastic oligodendrogliomas and grade IV glioblastomas and lung and melanoma metastases were analyzed for the expression of three matrix metalloproteinases (MMPs), two tissue inhibitors of MMPs (TIMPs) and for MMP activity. Some correlation was found between MMP expression and the degree of malignancy. Western blotting analysis revealed a more uniform pattern of distribution of MMP-2 (gelatinase A) than of MMP-9 (gelatinase B) and MMP-12 (metalloelastase) among tumors. MMP-9 levels were found to be significantly higher in grade III anaplastic astrocytomas and anaplastic oligodendrogliomas than those in grade I schwannomas and meningiomas. Anaplastic astrocytomas and Grade IV glioblastomas expressed significantly higher levels MMP-12 than grade I meningiomas. All sixty tumors showed a similar pattern of activity in zymography, proMMP-9 being the major species detected. Interestingly, TIMP-1 and TIMP-2 expression levels were especially low in tumors of grade II and grade III but significantly higher in tumors of grade I, particularly in schwannomas. Taken together, these data suggest that: 1) a balance between MMPs and TIMPs has an important role to play in human brain tumors; 2) TIMP expression may be valuable markers for tumor malignancy.

Identification of an immunodominant ABC transporter in methicillin-resistant Staphylococcus aureus infections

Immunoblotting sera from 26 patients with septicemia due to an epidemic strain of methicillin-resistant Staphylococcus aureus (EMRSA-15), 6 of whom died, revealed an immunodominant EMRSA-15 antigen at 61 kDa. There was a statistically significant correlate (P < 0.001) between survival and immunoglobulin G to the 61-kDa band. The antigen was identified by sequencing positive clones obtained by screening a genomic expression library of EMRSA-15 with pooled sera from patients taken after the septicemic episode. Eluted antibody reacted with the 61-kDa antigen on immunoblots. The amino terminus was obtained by searching the S. aureus NCTC 8325 and MRSA strain COL databases, and the whole protein was expressed in Escherichia coli TOP 10F'. The derived amino acid sequence showed homology with ABC transporters, with paired Walker A and Walker B motifs and 73% homology to YkpA from Bacillus subtilis. Epitope mapping of the derived amino acid sequence with sera from patients who had recovered from EMRSA-15 septicemia delineated seven epitopes. Three of these epitopes, represented by peptides 1 (KIKVYVGNYDFWYQS), 2 (TVIVVSHDRHFLYNNV), and 3 (TETFLRGFLGRMLFS), were synthesized and used to isolate human recombinant antibodies from a phage antibody display library. Recombinant antibodies against peptides 1 and 2 gave logarithmic reductions in organ colony counts, compared with control groups, in a mouse model of the infection. This study suggests the potential role of an ABC transporter as a target for immunotherapy.

Expression of matrix metalloproteinases and their inhibitors in human brain tumors

Sixty human brain tumors, including grade I meningiomas, schwannomas, and pilocytic astrocytomas, grade II astrocytomas, grade III anaplastic astrocytomas and oligodendrogliomas, and grade IV glioblastomas and lung and melanoma metastases were analyzed for expression of four matrix metalloproteinases (MMPs), two tissue inhibitors of MMPs (TIMPs), and MMP activity. No marked correlation was found between MMP expression and the degree of malignancy. Western blotting analysis revealed a more uniform pattern of distribution of MMP-2 (gelatinase A) than of MMP-9 (gelatinase B) and MMP-12 (metalloelastase) among tumors. All 60 tumors showed a similar pattern of activity in zymography, MMP-2 being the major species detected. Interestingly, TIMP-1 and TIMP-2 expression levels were low in tumors of grade III but significantly higher in tumors of grade I, particularly schwannomas. Altogether, these data suggest that: (1) the balance between MMP-2 and TIMP-2 is important in human brain tumors; and (2) TIMP expression may be a valuable marker for tumor malignancy.

Matrix metalloproteinases and their inhibitors in human pituitary tumors

OBJECTIVE

To determine the expression of matrix metalloproteinases (MMP)-1, -2, and -3 and the tissue inhibitors of metalloproteinases (TIMP)-1, -2, and -3 in 12 tissue samples from normal pituitary glands and in 28 human pituitary tumors ranging from Grade 0 to Grade IV, and to establish a correlation between the level of expression of MMPs and TIMPs and the tumor grade.

METHODS

The expression of MMPs and TIMPs was determined by Western blotting. MMP activity was detected by gelatin zymography.

RESULTS

MMPs were expressed in the majority of tumors, and their levels of expression were unrelated to tumor grade or to their invasive phenotype. Some correlation was observed between MMP activity detected by zymography and tumor grade. TIMP-2 and TIMP-3 were poorly expressed in high-grade tumors and strongly expressed in normal pituitary glands and in the majority of low-grade tumors.

CONCLUSION

No correlation could be established between the invasive potential of tumors and MMP-1, -2, and -3 expression levels. Some correlation was observed between MMP activity detected by zymography and tumor grade. A good inverse correlation was observed between TIMP-2 and TIMP-3 expression levels and tumor grade. These data suggest that monitoring the expression of TIMP-2 and TIMP-3 or gelatinolytic activity could be of prognostic value.

Inhibition of P-glycoprotein by cyclosporin A analogues and metabolites

The interaction between P-glycoprotein (P-gp) from membranes isolated from multidrug-resistant Chinese hamster ovary cells and cyclosporin A (CsA) analogues and its metabolites was characterized. Screening of these latter as chemosensitizers was performed using three different assays: (i) vinblastine uptake, (ii) photoaffinity labeling by [125I]iodoaryl azidoprazosin, and (iii) P-gp ATPase activity. Oxidation of the hydroxyl group at position I of CsA (200-096), CsG (215-834), or CsD (PSC-833) increased their inhibition of P-gp. CsA analogues (208-032, 208-183) modified at position 11 retained their ability to inhibit P-gp while analogues modified at position 2 (CsC and CsD) lost their efficiency. The inhibitions induced by metabolites of CsA were also compared to those obtained with CsG metabolites. From all the molecules tested, PSC-833 and 280-446 peptolide were the strongest inhibitors. Our results indicate that modifications of CsA analogues at position 1 and 2 are critical for their interaction with P-gp and that CsA metabolites retain a portion of the inhibitory activity of the parent drug.

Dexamethasone modulation of multidrug transporters in normal tissues

The expression of P-glycoprotein (P-gp) and canalicular multispecific organic anion transporter (cMOAT or Mrp2) was evaluated by Western blotting analysis of rat tissues isolated following daily administration (1 mg kg(-1) day(-1)) of dexamethasone over 4 days. Dexamethasone rapidly increased P-gp expression more than 4.5- and 2-fold in liver and lung, respectively, while it was decreased 40% in kidney. cMOAT expression was increased 2-fold in liver and kidney following dexamethasone treatment. The levels of both proteins returned to control values by 6 days after the conclusion of dexamethasone administration. These results indicate that dexamethasone can modulate P-gp and cMOAT expression in specific rat tissues and may have significant relevance for patients treated with dexamethasone as a single agent or in combination therapy with other drugs.

Immunodetection of a type III sodium-dependent phosphate cotransporter in tissues and OK cells

Polyclonal antibodies were raised in rabbits against a 14-amino acid portion of the gibbon ape leukemia virus human membrane receptor Glvr-1. This epitope also contained seven amino acids common to the receptor for the amphotropic murine retrovirus Ram-1. Antibody specificity and molecular size of Glvr-1/Ram-1-related proteins were assayed by Western blot. Using a standard Laemmli buffer system, under reducing conditions, a single band of approximately 85 kDa (designated p85) was immunodetected in membranes prepared from opossum kidney (OK) cells and in brain membranes from rat, rabbit and hamster. In mouse brain, p85 as well as a protein of 70-72 kDa were immunodetected. This protein was also present in several other mouse tissues. Limited proteolysis of p85 and the 70-72kDa-protein from mouse yielded similar peptide fragments, suggesting that both proteins are related. Fragments of the same molecular masses were also detected in OK cell membranes following proteolysis, showing that p85 in both models (mouse brain and OK cell) share a similar sequence. p85 is not N-glycosylated since an assay using endoglycosidase F/N-glycosidase F did not alter the electrophoretic mobility of p85. We also observed that regulation of phosphate transport by incubating OK cells without any phosphate or by PTH treatment occurs without any changes in the amount of p85. In conclusion, these data demonstrate for the first time a Western blot detection of a type III phosphate transporter using polyclonal antibodies. They also suggest that, conversely to type I and type II phosphate transporters which are localized in the kidney, this third type of transporter is ubiquitous and probably absorbs the readily available phosphate from interstitial fluid for normal cellular functions in many species and tissues, serving as a housekeeping Na+/Pi cotransport system. This is also the first report showing that p85 is not regulated in the same manner as type II phosphate transporters.

P-glycoprotein is strongly expressed in the luminal membranes of the endothelium of blood vessels in the brain

Luminal membranes of the vascular endothelium were isolated from brain, heart and lungs by modification of their density. The presence of P-glycoprotein (P-gp) was detected by Western blotting in luminal membranes from the endothelium of the three tissues. Strong enrichment in brain capillary luminal membranes, compared with brain capillaries (17-fold) and whole membranes (400-500-fold), indicates that P-gp is mainly located on the luminal side of the brain endothelium. Western blotting was also performed with antibodies directed against GLUT1, glial fibrillary acidic protein, adaptin, IP3R-3, integrins alphav and collagen IV as controls to determine whether the preparations were contaminated by other membranes. Strong enrichment of GLUT1 in brain capillary luminal membranes (9.9-fold) showed that the preparation consisted mainly of endothelial cell plasma membranes. Poor enrichment of glial fibrillary acidic protein (1.4-fold) and adaptin (2.4-fold) and a decreased level of IP3R-3, integrins alphav and collagen IV excludes the possibility of major contamination by astrocytes or internal and anti-luminal membranes. High levels of P-gp in the luminal membranes of brain capillary endothelial cells suggests that it may play an important role in limiting the access of anti-cancer drugs to the brain.

Various fructose-1,6-bisphosphatase mRNAs in mouse brain, liver, kidney and heart

The mouse fructose-1,6-bisphosphatase (FBPase) cDNA was previously cloned from testicular teratocarcinoma cultured cells (F9 cells). Using this published nucleotide sequence four primer sets were defined and used to amplify FBPase transcript from cerebral cortex, heart, kidney, liver and testis of male C57B1/6 mice. Only one primer set was efficient in all total RNA prepared from the various tissues. The restriction maps of these RNA amplification products suggested the existence of three different FBPase transcripts; this was confirmed by the nucleotide sequences of the FBPase transcripts and by the deduced amino acid sequences. These data are consistent with the existence of three different FBPase genes. This may be relevant in neurological disease in which abnormalities of brain glucose metabolism are involved.

Cyclosporin A treatment induces overexpression of P-glycoprotein in the kidney and other tissues

To see whether P-glycoprotein (PGP) expressed in renal brush-border membranes (BBM) could interact with compounds known as modulators of multidrug resistance (MDR), photoaffinity-labeling experiments were performed. A 145k-Da protein was photolabeled with [125I] iodoarylazidoprazosin, and this labeling was reduced in the presence of cyclosporin A (CsA) and PSC-833 (PSC). Interaction of CsA with PGP was further investigated by treating rats with daily subcutaneous injections of CsA (10 mg.kg-1.day-1). After this treatment, PGP expression levels were dramatically increased in renal BBM, intestine, liver, and many other tissues except the brain. This induction was a reversible process, since after cessation of CsA administration PGP levels declined to reach values similar to those of the control groups. The increase in PGP expression in the kidney was also detected in photolabeling experiments, suggesting the induction of a functional PGP. A higher dose of CsA (50 mg/kg) given as a bolus injection did not modify PGP expression] in renal BBM. These results demonstrate that CsA induces reversible overexpression of PGP in the rat. This may present significant relevance in the design of clinical trials using CsA as a chemosensitizing agent.

Molecular study of P-glycoprotein in multidrug resistance using surface plasmon resonance

P-Glycoprotein is an integral membrane protein which mediates the energy-dependent efflux of various antitumor agents from multidrug-resistant cancer cells. Surface plasmon resonance was used for the detection of P-glycoprotein after solubilization from drug-resistant and drug-sensitive Chinese hamster ovary cells and for the analysis of its interaction with cyclosporin A, a competitive inhibitor of drug efflux. Detection of P-glycoprotein relied on its binding to the monoclonal antibody C219 which was immobilized on a sensor chip. Binding of Zwittergent 3-14-solubilized P-glycoprotein to the antibody was concentration-dependent and reflected the relative abundance of P-glycoprotein in both cell lines. It was abolished when C219 was omitted or replaced by a rabbit anti-mouse IgG antibody and considerably reduced after precipitation of P-glycoprotein with wheat germ agglutinin. Preincubation of solubilized proteins with cyclosporin A increased the amount of protein bound to the antibody by approximately 30%. These results indicate that surface plasmon resonance is well suited to the detection of P-glycoprotein from biological samples and shows promise as a tool for the study of its interaction with different drugs.

P-glycoprotein of blood brain barrier: cross-reactivity of Mab C219 with a 190 kDa protein in bovine and rat isolated brain capillaries

P-glycoprotein (P-gp), an active efflux pump of antitumor drugs, is strongly expressed in endothelial cells of the blood brain barrier (BBB). Two proteins (155 and 190 kDa) were detected by Western blot analysis of beef and rat capillaries with the monoclonal antibody (MAb) C219. In order to characterize the nature of these proteins, their profile of solubilization by different detergents was established and compared with that of P-gp from the CHRC5 tumoral cell line. The 155 kDa protein (p155) of capillaries and the P-gp of CHRC5 cells were well solubilized by deoxycholate and Elugent, whereas the 190 kDa kDa protein (p190) was only solubilized by sodium dodecylsulfate (SDS). Both proteins have different patterns of extraction by Triton X-114, p155 partitioning as a membrane protein, while p190 was insoluble. Deglycosylation of capillary proteins resulted in a 27-28 kDa decrease in the apparent molecular weight of p155, similar to that observed for the P-gp of CHRC5 cells, but a decrease of only 7-8 for p190. Only p155 was immunoprecipitated by MAb C219. These results suggest that only p155 is the P-gp in BBB and that MAb C219 cross-reacts with a 190 kDa MDR-unrelated glycosylated protein. Consequently, the use of this antibody, which is frequently used to detect P-gp in tumors, could be a pitfall of immunohistochemistry screening for cancer tissues and lead to false positive in the diagnosis of MDR.