The Global Task Force for Chronic Pain in People with HIV (PWH): Developing a research agenda in an emerging field

Chronic pain is a common comorbidity in people with HIV (PWH), with prevalence estimates of 25-85%. Research in this area is growing, but significant gaps remain. A Global Task Force of HIV experts was organized to brainstorm a scientific agenda and identify measurement domains critical to advancing research in this field. Experts were identified through literature searches and snowball sampling. Two online questionnaires were developed by Task Force members. Questionnaire 1 asked participants to identify knowledge gaps in the field of HIV and chronic pain and identify measurement domains in studies of chronic pain in PWH. Responses were ranked in order of importance in Questionnaire 2, which was followed by a group discussion. 29 experts completed Questionnaire 1, 25 completed Questionnaire 2, and 21 participated in the group. Many important clinical and research priorities emerged, including the need to examine etiologies of chronic pain in PWH. Pain-related measurement domains were discussed, with a primary focus on domains that could be assessed in a standardized manner across various cohorts that include PWH in different countries. We collaboratively identified clinical and research priorities, as well as gaps in standardization of measurement domains, that can be used to move the field forward.

The sensory and affective components of pain: are they differentially modifiable dimensions or inseparable aspects of a unitary experience? A systematic review

BACKGROUND

Pain is recognised to have both a sensory dimension (intensity) and an affective dimension (unpleasantness). Pain feels like a single unpleasant bodily experience, but investigations of human pain have long considered these two dimensions of pain to be separable and differentially modifiable. The evidence underpinning this separability and differential modifiability is seldom presented. We aimed to fill this gap by evaluating the current evidence base for whether or not the sensory and affective dimensions of pain can be selectively modulated using cognitive manipulations.

METHODS

A rigorous systematic search, based on a priori search terms and consultation with field experts, yielded 4270 articles. A detailed screening process was based on the following recommendations: (i) evaluation of effectiveness; (ii) examination of methodological rigour, including each study having an a priori intention to cognitively modulate one of the two dimensions of pain; and (iii) sound theoretical reasoning. These were used to ensure that included studies definitively answered the research question.

RESULTS

After in-depth critique of all 12 articles that met the inclusion criteria, we found that there is no compelling evidence that the sensory and affective dimensions of pain can be selectively and intentionally modulated using cognitive manipulations in humans.

CONCLUSIONS

We offer potential explanations for this discrepancy between assumptions and evidence and contend that this finding highlights several important questions for the field, from both the research and clinical perspectives.

Smooth muscle in the annulus fibrosus of the tympanic membrane in bats, rodents, insectivores, and humans

The annulus fibrosus and its attachment to the bony tympanic ring were studied in a series of mammals. In the pallid bat, Antrozous pallidus, there is an extensive plexus of large interconnected blood sinuses in the part of the annulus that borders the tympanic bone. The spaces between the sinuses are packed with smooth muscle cells. Most of the cells have a predominately radial orientation; they extend from the bony tympanic sulcus to a dense collagenous matrix (apical zone) where radially oriented fibers of the pars tensa are confluent with the annulus. The muscles and vessels constitute a myovascular zone. A structurally similar myovascular zone is also present in the European hedgehog. In rodents, the annulus lacks the large interconnected blood sinuses but many small vessels are present. Smooth muscle is concentrated in the broad area of attachment of the annulus to the tympanic bone. In the gerbil, smooth muscle seems to be concentrated in the central part of the width of the annulus where it is attached to bone and radiates toward the tympanic membrane. In humans collections of radially oriented smooth muscle cells were found in several locations. The smooth muscle in all species studied appears to form a rim of contractile elements for the pars tensa. This arrangement suggests a role in controlling blood flow and/or creating and maintaining tension on the tympanic membrane.

Ultrastructure of the inner ear of NKCC1-deficient mice

The transduction of the auditory signal is dependent on the flow of ions within the inner ear. We have generated mice deficient in NKCC1, an ion cotransporter that is thought to be involved in the secretion of K+ by the strial marginal cells. Inner ear histology revealed partial to almost total absence of the scala media and collapse of Reissner's membrane. Ultrastructural analysis showed that Reissner's membrane consists of 3-4 cell layers instead of the usual two, and a substance of unknown composition is present between Reissner's membrane and underlying structures. Within the tunnel of Corti, hair cells and supporting cells were difficult to identify. The location of the tectorial membrane was altered, and a precipitate was observed surrounding it. Severe structural defects were noted in the interdental cells and Boettcher cells, and mild defects were observed in the stria vascularis and in type II and type IV fibrocytes. The finding that major defects occur predominantly in cells that are not known to express NKCC1 suggests that loss of NKCC1 results in functional defects in cells expressing NKCC1 and a morphological effect on cell populations downstream in the proposed K+ recycling pathway.

Adult-derived stem cells from the liver become myocytes in the heart in vivo

Recent evidence suggests that adult-derived stem cells, like their embryonic counterparts, are pluripotent. These simple, undifferentiated and uncommitted cells are able to respond to signals from their host tissue microenvironment and differentiate, producing progeny that display a phenotype characteristic of the mature cells of that tissue. We used a clonal stem cell line (termed WB-F344) that was derived from an adult male rat liver to investigate the possibility that uncommitted stem cells from a nonmyogenic tissue source would respond to the tissue microenvironment of the heart in vivo and differentiate into cardiac myocytes. Male WB-F344 cells that carry the Escherichia coli beta-galactosidase gene were identified in the left ventricular myocardium of adult female nude mice 6 weeks after transplantation. We confirmed the presence of a rat Y-chromosome-specific repetitive DNA sequence exclusively in the beta-galactosidase-positive myocytes by polymerase chain reaction and fluorescence in situ hybridization. Immunohistochemistry, using a cardiac troponin T-specific monoclonal antibody, and ultrastructural analysis confirmed a cardiac myocyte phenotype of the stem cell-derived myocytes. The beta-galactosidase-positive myocytes ranged from < 20 microm to 110 microm in length. The longer of these cells contained well-organized sarcomeres and myofibrils, and formed intercalated disks and gap junctions with endogenous (host-derived) myocytes, suggesting that WB-F344-derived myocytes participate in the function of the cardiac syncytium. These results demonstrate that adult liver-derived stem cells respond to the tissue microenvironment of the adult heart in vivo and differentiate into mature cardiac myocytes.

A newly characterized human endometrial adenocarcinoma cell line (CAC-1) differentiates in response to retinoic acid treatment

A new cell line of poorly differentiated human endometrial adenocarcinoma cells termed "CAC-1" cells has been established. These cells are epithelial, as indicated by positive cytokeratin and negative vimentin staining. They are rounded and possess a high nuclear-to-cytoplasmic ratio, desmosomes, surface microvilli, intercelular lumens, and pleomorphic nuclei containing multiple nucleoli. These cells have been in long-term culture for 2 years. Our previous studies demonstrated that moderately differentiated (RL95-2) cells differentiated in response to retinoic acid treatment, illustrated by their reorganization of actin filaments and cell enlargement (Carter et al., 1996; Anticancer Res. 16, 17-24). CAC-1 cells exhibited a similar response because they also organized actin filaments and enlarged in response to retinoic acid treatment. Concurrently, retinoic acid treatment caused a 40% decrease in cell detachment in an in vitro detachment assay compared to controls. A slight lag in cell growth was observed when CAC-1 cells were treated with 1 microM 13-cis or all-trans retinoic acid during a 12-day growth curve. In addition, we examined the effects of retinoic acid on protein kinase C-alpha (PKC-alpha) and myristoylated alanine-rich C-kinase substrate (MARCKS). Treatment with retinoic acid caused cytoplasmic PKC-alpha to increase concomitant with a decrease in PKC-alpha in the membrane. In contrast, MARCKS increased in the membrane in response to retinoic acid treatment. These data indicate that retinoid treatment causes inactivation of PKC-alpha, allowing MARCKS to relocalize to the membrane, where it can cross-link actin filaments. CAC-1 cells represent an ideal model for investigating the effects of retinoids on differentiation induction concomitant with actin reorganization.

Comparative neurotoxicity of oxaliplatin, cisplatin, and ormaplatin in a Wistar rat model

Oxaliplatin (4 mg/kg), cisplatin (2 mg/kg with 20 mg/kg mannitol) and ormaplatin (2 mg/kg) were administered i.p. twice weekly for 4.5 weeks. Lactose injections (0.9%) were used as a control for oxaliplatin and 0.9% saline injections were used as a control for cisplatin and ormaplatin. Morphometric changes to dorsal root ganglia L4-L6 were quantitated as a measure of neurotoxicity. Drug treatment resulted in a decrease in cell and nuclear area and an increase in the percentage of cells with eccentric nucleoli for neuronal cell bodies in the DRG. Immediately following treatment the order of morphometric changes was ormaplatin > cisplatin > or = oxaliplatin. The accumulation of platinum in the DRG was measured by inductively coupled plasma mass spectrometry. The order of accumulation was cisplatin > oxaliplatin > ormaplatin. Following an 8-week recovery period the order of morphometric changes to the DRG was ormaplatin approximately equal to oxaliplatin > cisplatin. This correlated with a greater retention of platinum by the DRG for ormaplatin and oxaliplatin than for cisplatin. The results suggest that ormaplatin is uniquely neurotoxic immediately following treatment in the Wistar rat model. However, following an 8-week recovery period both ormaplatin and oxaliplatin are more neurotoxic than cisplatin and this neurotoxicity correlates with a greater retention of platinum by the DRG.

Rapid decalcification of temporal bones with preservation of ultrastructure

Decalcification of temporal bones, especially from primates, has routinely required long periods of time and has been a major deterrent to many types of morphological studies. In this investigation, temporal bones from the monkey, Macaca fuscata, were decalcified with ethylene diamine tetraacetic acid (EDTA) in a microwave oven. To isolate effects of microwaves on decalcification, tissue was fixed and embedded using routine methods; only decalcification was carried out in the microwave oven. The procedure is described in detail. Instead of months, decalcification was complete in two working days. Control procedures included decalcification at room temperature and use of a regular oven at a temperature equal to that reached in the microwave. The ultrastructure of cochlear tissue was equal to or better than that obtained with routine decalcification.

Host-derived intracellular immunization against mouse hepatitis virus infection

Mouse hepatitis virus (MHV) utilizes the murine biliary glycoprotein receptor (BgpA) for entry into susceptible cells. The Bgp1 gene was transfected into a murine DBT cell clone that expressed little if any BgpA receptor and resisted wild-type MHV infection. Clones which expressed low levels of receptor were efficient hosts for MHV-A59 replication. Clones which expressed 20- to 69-fold more BgpA receptor than controls were also susceptible to MHV-A59 infection, yet few infectious progeny virions were released. Pretreatment of clones with monoclonal antibody CC1, which binds to the N-terminus of BgpA, blocked MHV-A59 replication in DBT clones that expressed wild-type levels of receptor protein. In the overexpressing cell clones, however, CC1 pretreatment reversed the BgpA overexpression blockade and increased virus titers by 3-4 logs. BgpA overexpression inhibited the formation of infectious extracellular and intracellular virions, but levels of virus transcription were equivalent to those of controls. Ultrastructural studies revealed normal cell cytopathology in both the MHV-A59-infected controls and the overexpressing cell clones. Although equivalent numbers of virions were released compared with the control, peplomer spike glycoproteins were rarely evident in virions derived from the BgpA-overexpressing cell clones. Consonant with these findings, purified virions from BgpA-overexpressing cell clones demonstrated a 70% reduction in the amount of S glycoprotein, but not of N or M proteins. These data suggest that BgpA receptor overexpression establishes an intracellular trap which blocks MHV replication during the maturation and release of infectious progeny virions.

Endothelium specific Weibel-Palade bodies in a continuous human cell line, EA.hy926

Weibel-Palade bodies are ultrastructurally defined organelles found only in vascular endothelial cells. Because endothelium in corpo is very dispersed, isolation and further characterization of this organelle has been dependent on increasing the number of cells in culture. However, primary isolates of endothelial cells have a limited replication potential and tend to senesce in culture. In this report, EA.hy926, a continuously replicating cell line derived from human endothelium, is shown to contain Weibel-Palade bodies. Electron micrographs demonstrate the ultrastructural characteristics of these tissue-specific organelles and their cytoplasmic distribution in EA.hy926 cells. Von Willebrand factor, which has been shown to exist in Weibel Palade bodies, is demonstrated by immunofluorescence in discrete rod-shaped organelles whose size, shape, and distribution are consistent with that of Weibel-Palade bodies in primary endothelial cell cultures. Rapid release of von Willebrand factor can be induced by calcium ionophore, and large multimeric forms of the protein are found in EA.hy926 cells. These two properties are consistent with the function currently ascribed to Weibel Palade bodies: storage of multimerized von Willebrand factor. Thus ultrastructural, immunologic, and functional data establish the existence of this as yet poorly understood tissue-specific organelle in a continuous, vigorously replicating human cell line.