Health need and the use of alternative medicine among adults who do not use conventional medicine

Background

We hypothesize that a substantial portion of individuals who forgo conventional care in a given year turn to some form of alternative medicine. This study also examines whether individuals who use only alternative medicine will differ substantially in health and sociodemographic status from individuals using neither alternative medicine nor conventional care in a given year. To identify those factors that predict alternative medicine use in those not using conventional care, we employed the socio-behavioral model of healthcare utilization.

Methods

The current study is a cross-sectional regression analysis using data from the 2002 National Health Interview Survey. Data were collected in-person from 31,044 adults throughout the 50 states and the District of Columbia.

Results

19.3% of adults (38.3 million) did not use conventional care in a 12 month period, although 39.5% of these individuals (14.7 million) reported having one or more problems with their health. Of those not using conventional care, 24.8% (9.5 million) used alternative medicine. Users of alternative medicine had more health needs and were more likely to delay conventional care because of both cost and non-cost factors compared to those not using alternative medicine. While individual predisposing factors (gender, education) were positively associated with alternative medicine use, enabling factors (poverty status, insurance coverage) were not.

Conclusions

We found that a quarter of individuals who forgo conventional care in a given year turn towards alternative medicine. Our study suggests that the potential determinants of using only alternative medicine are multifactorial. Future research is needed to examine the decision process behind an individual's choice to use alternative medicine but not conventional medicine and the clinical outcomes of this choice.

Guidance from an NIH workshop on designing, implementing, and reporting clinical studies of soy interventions

The NIH sponsored a scientific workshop, "Soy Protein/Isoflavone Research: Challenges in Designing and Evaluating Intervention Studies," July 28-29, 2009. The workshop goal was to provide guidance for the next generation of soy protein/isoflavone human research. Session topics included population exposure to soy; the variability of the human response to soy; product composition; methods, tools, and resources available to estimate exposure and protocol adherence; and analytical methods to assess soy in foods and supplements and analytes in biologic fluids and other tissues. The intent of the workshop was to address the quality of soy studies, not the efficacy or safety of soy. Prior NIH workshops and an evidence-based review questioned the quality of data from human soy studies. If clinical studies are pursued, investigators need to ensure that the experimental designs are optimal and the studies properly executed. The workshop participants identified methodological issues that may confound study results and interpretation. Scientifically sound and useful options for dealing with these issues were discussed. The resulting guidance is presented in this document with a brief rationale. The guidance is specific to soy clinical research and does not address nonsoy-related factors that should also be considered in designing and reporting clinical studies. This guidance may be used by investigators, journal editors, study sponsors, and protocol reviewers for a variety of purposes, including designing and implementing trials, reporting results, and interpreting published epidemiological and clinical studies.

Role of self-concept in answering survey questions on complementary and alternative medicine: challenges to and strategies for improving data quality

OBJECTIVES

The aim of this study was to assess the construct validity of survey questions about the use of herbal and other nonvitamin/nonmineral dietary supplements.

DESIGN

We conducted one-on-one, in-depth cognitive interviews with 32 respondents to test questions from the complementary and alternative medicine (CAM) supplement for the 2007 National Health Interview Survey. Respondents were sampled purposively according to their use of CAM. Interviewers probed respondents for their understanding of the questions, and analysis was guided by grounded theory, an approach that generates explanations of response error that are closely tied to the empirical data.

RESULTS

We found two sources of misinterpretation of CAM questions. First, some respondents did not have any pre-established definition of what constitutes an herbal supplement while others had interpretations that did not match the intended definitions. These problems are common to many survey questions. However, a second finding is that misinterpretation also arose when respondents incorporated notions of self-concept into the act of taking "natural herbs," and answered based on their understanding of this image rather than on actual behavior.

CONCLUSIONS

There are several sources of misinterpretation of CAM questions. One of the most important sources is whether or not the respondent has created a concept of self-image that includes the use of herbal supplements. Common questionnaire design techniques such as providing definitions to respondents will not help to eliminate misinterpretation due to self-image. We found that careful question wording that does not evoke definitions of self, combined with visual aids that narrow the focus of the questions, can lead to more accurate answers.

Costs of complementary and alternative medicine (CAM) and frequency of visits to CAM practitioners: United States, 2007

OBJECTIVE

This report presents selected estimates of costs of complementary and alternative medicine (CAM) use among U.S. adults, the frequency of visits made to CAM providers, and the frequency of purchases of self-care CAM therapies. Data from the 2007 National Health Interview Survey (NHIS), which is conducted by the Centers for Disease Control and Prevention's National Center for Health Statistics, are used in this report.

METHODS

Estimates were derived from the Complementary and Alternative Medicine Supplement of the 2007 NHIS, sponsored by the National Center for Complementary and Alternative Medicine, which is part of the National Institutes of Health. Estimates were generated using the SUDAAN statistical package to account for the NHIS complex sample design.

RESULTS

In 2007, adults in the United States spent $33.9 billion out of pocket on visits to CAM practitioners and purchases of CAM products, classes, and materials. Nearly two-thirds of the total out-of-pocket costs that adults spent on CAM were for self-care purchases of CAM products, classes, and materials during the past 12 months ($22.0 billion), compared with about one-third spent on practitioner visits ($11.9 billion). Despite this emphasis on self-care therapies, 38.1 million adults made an estimated 354.2 million visits to practitioners of CAM. About three-quarters of both visits to CAM practitioners and total out-of-pocket costs spent on CAM practitioners were associated with manipulative and body-based therapies. A total of 44% of all out-of-pocket costs for CAM, or about $14.8 billion, was spent on the purchase of nonvitamin, nonmineral, natural products.

Concomitant use of prescription drugs and dietary supplements in ambulatory elderly people

OBJECTIVES

To analyze baseline data on concomitant use of prescription drugs and dietary supplements in elderly people from the Ginkgo Evaluation of Memory (GEM) Study, in which information was collected on all drugs and supplements used by participant.

DESIGN

Cross-sectional correlation analysis.

SETTING

GEM Study sites in California, Maryland, North Carolina, and Pennsylvania.

PARTICIPANTS

Three thousand seventy ambulatory individuals aged 75 and older enrolled between September 2000 and June 2002.

MEASUREMENTS

Use of prescription drugs and dietary supplements identified through bottles brought to the clinic.

RESULTS

Almost three-quarters (74.2%) of the cohort combined use of at least one prescription drug and one dietary supplement, with 32.5% using three or more prescription drugs and three or more supplements. The 15 most-prevalent prescription drugs exhibited substantial concomitant use with dietary supplements, ranging from 77.6% for diuretics to 93.6% for estrogen preparations. Although supplements were taken concomitantly with all classes of prescription drugs, the use of supplements was more likely in individuals using nonsteroidal anti-inflammatory drugs, thyroid drugs, and estrogens. The use of drugs for diabetes mellitus was negatively associated with the use of supplements, with most of this attributed to low use in those taking multivitamins, glucosamine and chondroitin, and echinacea.

CONCLUSION

There is substantial concomitant use of prescription drugs and dietary supplements in elderly people. Further investigations are needed to define the clinical importance of this concomitant use, especially in elderly patients who consume multiple prescription drugs or have experienced an adverse event secondary to their prescription medications.

Complementary and alternative medicine use among adults and children: United States, 2007

OBJECTIVE

This report presents selected estimates of complementary and alternative medicine (CAM) use among U.S. adults and children, using data from the 2007 National Health Interview Survey (NHIS), conducted by the Centers for Disease Control and Prevention's (CDC) National Center for Health Statistics (NCHS). Trends in adult use were assessed by comparing data from the 2007 and 2002 NHIS.

METHODS

Estimates were derived from the Complementary and Alternative Medicine supplements and Core components of the 2007 and 2002 NHIS. Estimates were generated and comparisons conducted using the SUDAAN statistical package to account for the complex sample design.

RESULTS

In 2007, almost 4 out of 10 adults had used CAM therapy in the past 12 months, with the most commonly used therapies being nonvitamin, nonmineral, natural products (17.7%) and deep breathing exercises (12.7%). American Indian or Alaska Native adults (50.3%) and white adults (43.1%) were more likely to use CAM than Asian adults (39.9%) or black adults (25.5%). Results from the 2007 NHIS found that approximately one in nine children (11.8%) used CAM therapy in the past 12 months, with the most commonly used therapies being nonvitamin, nonmineral, natural products (3.9%) and chiropractic or osteopathic manipulation (2.8%). Children whose parent used CAM were almost five times as likely (23.9%) to use CAM as children whose parent did not use CAM (5.1%). For both adults and children in 2007, when worry about cost delayed receipt of conventional care, individuals were more likely to use CAM than when the cost of conventional care was not a worry. Between 2002 and 2007 increased use was seen among adults for acupuncture, deep breathing exercises, massage therapy, meditation, naturopathy, and yoga. CAM use for head or chest colds showed a marked decrease from 2002 to 2007 (9.5% to 2.0%).

Ginkgo biloba for prevention of dementia: a randomized controlled trial

CONTEXT

Ginkgo biloba is widely used for its potential effects on memory and cognition. To date, adequately powered clinical trials testing the effect of G. biloba on dementia incidence are lacking.

OBJECTIVE

To determine effectiveness of G. biloba vs placebo in reducing the incidence of all-cause dementia and Alzheimer disease (AD) in elderly individuals with normal cognition and those with mild cognitive impairment (MCI).

DESIGN, SETTING, AND PARTICIPANTS

Randomized, double-blind, placebo-controlled clinical trial conducted in 5 academic medical centers in the United States between 2000 and 2008 with a median follow-up of 6.1 years. Three thousand sixty-nine community volunteers aged 75 years or older with normal cognition (n = 2587) or MCI (n = 482) at study entry were assessed every 6 months for incident dementia.

INTERVENTION

Twice-daily dose of 120-mg extract of G. biloba (n = 1545) or placebo (n = 1524).

MAIN OUTCOME MEASURES

Incident dementia and AD determined by expert panel consensus.

RESULTS

Five hundred twenty-three individuals developed dementia (246 receiving placebo and 277 receiving G. biloba) with 92% of the dementia cases classified as possible or probable AD, or AD with evidence of vascular disease of the brain. Rates of dropout and loss to follow-up were low (6.3%), and the adverse effect profiles were similar for both groups. The overall dementia rate was 3.3 per 100 person-years in participants assigned to G. biloba and 2.9 per 100 person-years in the placebo group. The hazard ratio (HR) for G. biloba compared with placebo for all-cause dementia was 1.12 (95% confidence interval [CI], 0.94-1.33; P = .21) and for AD, 1.16 (95% CI, 0.97-1.39; P = .11). G. biloba also had no effect on the rate of progression to dementia in participants with MCI (HR, 1.13; 95% CI, 0.85-1.50; P = .39).

CONCLUSIONS

In this study, G. biloba at 120 mg twice a day was not effective in reducing either the overall incidence rate of dementia or AD incidence in elderly individuals with normal cognition or those with MCI. Trial Registration clinicaltrials.gov Identifier: NCT00010803.

Associations of gait speed and other measures of physical function with cognition in a healthy cohort of elderly persons

BACKGROUND

Recent evidence suggests that physical decline and slower gait may be associated with early signs of dementia, but more information on healthy older adults is needed.

METHODS

We determined associations between cognitive function, gait speed, and self-reported measures of physical function in 3035 healthy mobile participants of the Ginkgo Evaluation of Memory Study evaluated in 2000-2001. Gait speed was measured over a 15-foot course with participants walking at both their usual and rapid pace. Self-reported difficulties with Activities of Daily Living (ADLs) and other physical function tasks were also collected. Results of the Modified Mini-Mental State Examination (3MSE) determined cognitive function.

RESULTS

The average age of the cohort was 78.6 years (standard deviation [SD] 3.3), and 53.9% of participants were men. Mean gait speed was 0.95 (SD 0.23) m/s at a usual pace and 1.35 (SD 0.58) m/s at a rapid pace. More than three-fourths of participants had 3MSE scores > 90. In multiple logistic models adjusted for demographics and comorbidities, risk of low cognition (defined as 3MSE score of 80-85) was almost twice as great for participants in the slowest quartile of the rapid-paced walking task than for the fastest walkers (odds ratio: 1.96, 95% confidence interval, 1.25-3.08). Associations between cognition and usual-paced walking were borderline, and no relationships were found with self-reported measures of physical function, including ADLs.

CONCLUSIONS

In very healthy older adults, performance-based measures better predict early cognitive decline than do subjective measures, and tasks requiring greater functional reserve, such as fast-paced walking, appear to be the most sensitive in assessing these relationships.

Health behaviors and risk factors in those who use complementary and alternative medicine

BACKGROUND

Surveys have generally found that individuals more likely to use complementary and alternative medicine are female, live in the western United States, are likely to have a health complaint, and have a higher socioeconomic status than do nonusers. What is not known is the extent to which those who use complementary and alternative medicine also engage in positive health behaviors, such as smoking cessation or increased physical activity and/or exhibit fewer health risk factors such as obesity. This has been identified as a key research question in a recent Institute of Medicine report. In the present study we sought to determine whether the use of complementary and alternative medicine is associated with health behaviors or risk factors known to impact on health status.

METHODS

The current study is a cross-sectional regression analysis using data from the 2002 National Health Interview Survey. Data were collected in-person from 31,044 adults throughout the 50 states and the District of Columbia.

RESULTS

After controlling for a range of other factors, we found that engaging in leisure-time physical activity, having consumed alcohol in one's life but not being a current heavy drinker, and being a former smoker are independently associated with the use of CAM. Obese individuals are slightly less likely to use CAM than individuals with a healthy body-mass index. No significant associations were observed between receipt of an influenza vaccine and CAM use.

CONCLUSION

Those engaging in positive health behaviors and exhibiting fewer health risk factors are more likely to use CAM than those who forgo positive health behaviors or exhibit more health risk factors. The fact that users of CAM tend to pursue generally healthy lifestyles suggests that they may be open to additional recommendations toward optimizing their health.

Use of herbal medicine and other dietary supplements in community-dwelling older people: Baseline data from the ginkgo evaluation of memory study

OBJECTIVES

To analyze baseline data from the Ginkgo Evaluation of Memory (GEM) study, in which information was collected on the use of all dietary supplements.

DESIGN

Cross-sectional regression analysis.

SETTING

GEM study sites in California, Maryland, North Carolina, and Pennsylvania.

PARTICIPANTS

The GEM study enrolled 3,072 ambulatory individuals aged 75 and older between September 2000 and June 2002.

MEASUREMENTS

Self-reported use of dietary supplements and use identified through bottles brought to the clinic.

RESULTS

Respectively, 59.4%, 66.6%, and 27.4% of the GEM study cohort used a multivitamin, at least one individual vitamin or mineral supplement, and some type of nonvitamin/nonmineral dietary supplement (NVNMDS). In logistic regression models, multivitamin use was associated with female sex, a higher income, a higher modified Mini-Mental State Examination score, difficulty with mobility, and asthma history; use of any other vitamin or mineral was associated with female sex, white race, nonsmoking, more years of schooling, difficulty walking, a history of osteoporosis, and reading health and senior magazines; and NVNMDS use was associated with residing in California, having difficulties with muscle strength, and reading health and senior magazines.

CONCLUSION

There were substantial differences between individuals who used vitamins and minerals and those who used NVNMDS. These data require that trial investigators pay close attention to participant use of off-protocol dietary supplements. In addition, these findings may help identify elderly individuals likely to combine NVNMDS and prescription drugs.

Insomnia, trouble sleeping, and complementary and alternative medicine: Analysis of the 2002 national health interview survey data

BACKGROUND

Insomnia and other disorders that result in trouble sleeping are common in the United States and are often associated with chronic health conditions. Some individuals with insomnia or trouble sleeping use complementary and alternative medicine (CAM) therapies to treat their condition, but the prevalence of such use and the most common types of CAM therapies selected are not known.

METHODS

Prevalence of insomnia or trouble sleeping and of CAM use for treating such conditions was examined using the 2002 National Health Interview Survey. Logistic regression was used to examine associations between insomnia or trouble sleeping, comorbid conditions, and use of CAM treatments.

RESULTS

The 12-month prevalence rate of insomnia or trouble sleeping was 17.4%. There was a strong positive association between adults who reported having insomnia or trouble sleeping and adults who reported 4 of 5 common conditions: obesity (adjusted odds ratio [OR], 1.15; 99% confidence interval [CI], 1.01-1.31), hypertension (OR, 1.32; 99% CI, 1.16-1.51), congestive heart failure (OR, 2.24; 99% CI, 1.60-3.14), and anxiety or depression (OR, 5.64; 99% CI, 5.07-6.29). Of those with insomnia or trouble sleeping, 4.5% used some form of CAM therapy to treat their condition.

CONCLUSIONS

According to the National Health Interview Survey analysis, over 1.6 million civilian, noninstitutionalized adult US citizens use CAM to treat insomnia or trouble sleeping. The details of this analysis will serve as a guide for future research on CAM therapies for sleep disorders.

Identifying and pursuing research priorities at the National Center for Complementary and Alternative Medicine

As part of its planning process, the National Center for Complementary and Alternative Medicine (NCCAM), a component of the National Institutes of Health, periodically evaluates how well it applies its criteria for setting research priorities. For its most recent evaluation, NCCAM compared funding levels in fiscal years 2000 and 2003 for 18 diseases with a substantial public health burden including Alzheimer's disease, arthritis, back pain, cancer, diabetes, coronary heart disease, HIV/AIDS, migraine, and stroke, with 7 measures of disease burden: 1) prevalence, 2) mortality, 3) years of life lost (YLL), 4) years lost to disability (YLD), 5) disability-adjusted life years (DALY's), 6) direct costs of illness (COI), and 7) total COI. There is an increasing relationship between NCCAM research funding and disease burden over the 4-year study period that reflects funding of specific research initiatives. The strength of the individual correlations varied among measures, with the strongest correlations seen with total COI and the weakest seen with mortality. When applied with its other criteria, measures of disease burden aid identification and matching of NCCAM priorities with levels of support.

Racing Toward The Integration Of Complementary And Alternative Medicine: A Marathon Or A Sprint?

Health care opinion leaders concur that integration of complementary and alternative medicine (CAM) into the U.S. health care system must be based on strong supporting evidence of safety and efficacy. As others have pointed out, integration is under way, despite the lack of reliable, rigorous science supporting the use of most CAM treatments. We contend that optimal integration of CAM is a long-term endeavor--a marathon rather than a sprint. The evidence base does not now support its wholesale assimilation; market forces, although compelling, should not be the primary consideration in integration.

Complementary and alternative medicine use among adults: United States, 2002

OBJECTIVE

This report presents selected estimates of complementary and alternative medicine (CAM) use among U.S. adults, using data from the 2002 National Health Interview Survey (NHIS), conducted by the Centers for Disease Control and Prevention's (CDC) National Center for Health Statistics (NCHS).

METHODS

Data for the U.S. civilian noninstitutionalized population were collected using computer-assisted personal interviews (CAPI). This report is based on 31,044 interviews of adults age 18 years and over. Statistics shown in this report were age adjusted to the year 2000 U.S. standard population.

RESULTS

Sixty-two percent of adults used some form of CAM therapy during the past 12 months when the definition of CAM therapy included prayer specifically for health reasons. When prayer specifically for health reasons was excluded from the definition, 36% of adults used some form of CAM therapy during the past 12 months. The 10 most commonly used CAM therapies during the past 12 months were use of prayer specifically for one's own health (43.0%), prayer by others for one's own health (24.4%), natural products (18.9%), deep breathing exercises (11.6%), participation in prayer group for one's own health (9.6%), meditation (7.6%), chiropractic care (7.5%), yoga (5.1%), massage (5.0%), and diet-based therapies (3.5%). Use of CAM varies by sex, race, geographic region, health insurance status, use of cigarettes or alcohol, and hospitalization. CAM was most often used to treat back pain or back problems, head or chest colds, neck pain or neck problems, joint pain or stiffness, and anxiety or depression. Adults age 18 years or over who used CAM were more likely to do so because they believed that CAM combined with conventional medical treatments would help (54.9%) and/or they thought it would be interesting to try (50.1%). Most adults who have ever used CAM have used it within the past 12 months, although there is variation by CAM therapy.

National Center for Complementary and Alternative Medicine perspectives for complementary and alternative medicine research in cardiovascular diseases

The National Center for Complementary and Alternative Medicine (NCCAM) was established in 1998 by the US Congress to conduct and support basic and applied research and research training and disseminate information with respect to identifying, investigating, and validating complementary and alternative therapies. Because of limited appropriations, NCCAM prioritizes its research programs according to the relative use of a modality, the evidence supporting its value and safety, and opportunities to advance the relevant fields of science. While NCCAM's top priority is supporting clinical trials of alternative therapeutics, increasingly it is supporting basic and preclinical research. To accomplish its mission, NCCAM encourages the research community to undertake high-quality and rigorous research in complementary and alternative medicine (CAM). In the area of cardiovascular diseases, NCCAM is supporting clinical trials, specialized centers, research training, and investigator-initiated projects. Virtually all aspects of CAM modalities are open for investigation. Current NCCAM projects are investigating Tai Chi (Taiji) exercise, hawthorn, phytoestrogens, biofeedback, Ayurvedic herbals, acupuncture, qigong, Reiki, meditation, spirituality, Ginkgo biloba, ethylenediaminetetraacetic acid chelation therapy, and special diets.

Use of the best case series to evaluate complementary and alternative therapies for cancer: a systematic review

The best case series (BCS) is a retrospective chart review that describes a series of patients who all appear to have benefitted from the treatment under study. The BCS has been advocated as the first research step for evaluating complementary and alternative medicine (CAM) treatments for cancer. However, the research value of the BCS has not been assessed. To address this deficiency, the present study evaluates the primary characteristics of the BCS process through a systematic review of the English language scientific literature. Twenty-four individual BCS investigating 16 unique CAM treatments for cancer were identified. About half of the BCS reported evidence of tumor regression in association with a particular CAM treatment, but only six contained documentation adequate for publication in peer-reviewed journals. For these six BCS the number of responders per BCS ranged from 2 to 12 (median, 3.5), the proportion of responders in the total number of evaluated cases varied from 6% to 100% (median, 40%), and the proportion of evaluated cases to identified cases ranged from 18% to 53% (median, 29%). The primary factors confounding the identified BCS were lack of documentation of disease and/or the use of concurrent or recent conventional treatment. Despite these general deficiencies, four BCS (antineoplastons, hydrazine sulfate, laetrile, and Kelly-Gonzalez) were sufficiently convincing to warrant follow-up clinical trials. These data suggest that while well-documented BCS do have an impact on the research agenda, in general, additional rigor is needed during their compilation.

Comparison of c-jun, junB, and junD mRNA expression and protein in the rat dorsal root ganglia following sciatic nerve transection

The present study was designed to compare the expression of the Jun family of protooncogenes following nerve injury. Adult rats were anesthetized and the sciatic nerve transected. Dorsal root ganglia (DRG) at 1, 2, 3, and 7 days after nerve transection were collected, their total RNA extracted, and Northern blots performed using 32P-labeled oligonucleotide probes. The constitutive expression of c-jun mRNA was very low in DRG. Induction of c-jun mRNA was observed by day 1 after nerve transection, with a sixfold peak at 3 days and a twofold induction still present by day 7. The constitutive expression of junB mRNA was also low in the DRG, and sciatic nerve transection produced only a modest induction (1.7-fold by day 3) in the DRG ipsilateral to the nerve cut. junD mRNA was constitutively expressed at high levels in the DRG, and its level of expression did not in the DRG, and its level of expression did not change after sciatic nerve transection. Immunocytochemistry studies demonstrated a pattern of c-Jun, JunB, and JunD immunoreactivity (IR) associated with the cell nuclei of DRG neurons. c-Jun IR was found at very low levels in the undamaged contralateral DRG neurons, but sciatic nerve transection dramatically increased the number of c-Jun-immunoreactive neurons. Dot blot immunoblotting assay confirmed that the DRG ipsilateral to the sciatic nerve cut contained a higher level of c-Jun protein than the contralateral control DRG. Similar to c-Jun IR, JunB IR was minimal in the undamaged contralateral DRG. However, the DRG ipsilateral to the nerve transection did not show an increase in the number of immunoreactive neurons. JunD protein was expressed at high levels in the contralateral DRG, and this level of expression persisted after sciatic nerve transection in the ipsilateral DRG. DNA gel retardation assay experiments with an AP-1 consensus sequence showed a single DNA-protein complex. This complex was increased in ipsilateral as compared with contralateral DRG extracts. The amount of DNA-protein complex was reduced by c-Jun protein antiserum but was not altered when treated with a Fos antibody. We conclude that c-jun, junB and junD mRNAs and proteins are differentially regulated in the DRG after sciatic nerve transection.

Adjuvant-induced inflammation of rat paw is associated with altered calcitonin gene-related peptide immunoreactivity within cell bodies and peripheral endings of primary afferent neurons

Local inflammation is associated with profound changes in the biochemistry and physiology of primary afferent nerve fibers and the central neurons responding to their signals. In some tissues, the neural changes accompanying inflammation include sprouting and cytochemical changes that are delayed several days after the initial injury. In the present study, we have analyzed the effect of complete Freund's adjuvant (CFA)-induced inflammation in the rat paw on calcitonin gene-related peptide (CGRP) immunoreactivity (IR) in dorsal root ganglia and within tissue of the inflamed paw. We quantified the CGRP-IR within the L1, L4, and L6 ganglia, and in ankle, midpaw, joint and toe tissues. Analysis of the processed tissue revealed a significant increase in the percentage of CGRP-positive cells within L4 dorsal root ganglia ipsilateral to an inflamed hindpaw six days after administration of CFA. There was a parallel increase in the number and staining density of detectable CGRP-immunoreactive fibers in periarticular and perivascular tissues of the inflamed digits and inflamed ankle. The other tissues of the paw, including epidermis and the regions surrounding the abcesses, did not have detectable changes in CGRP-immunoreactive fibers, despite tissue swelling and dystrophic changes in the foot that included loss of mast cell staining. These data demonstrate that local inflammation of the rat paw has delayed influences on the peripheral nervous system, in addition to a number of previously characterized acute effects. The alterations of CGRP-IR were focused around specific tissue types, such as joints and subdermal blood vessels, and absent from others, such as epidermis or in the areas surrounding abscesses. This suggests production of local factors within reactive tissues that selectively interact with nerve fibers to induce changes in CGRP-IR within the fibers.

Primary sensory neurons exhibit altered gene expression in a rat model of neuropathic pain

Using a number of complementary anatomical and molecular techniques, we studied the effects of chronic constriction injury (CCI), a model of partial nerve injury that elicits behavioral hyperalgesia, on primary sensory neurons in the rat. Dorsal root ganglia taken from animals with CCI were analyzed for alterations in mRNA levels encoding growth-associated protein-43 (GAP-43), calcitonin gene-related peptide (CGRP), galanin (GAL), neuropeptide Y (NPY), substance P (SP), and vasoactive intestinal polypeptide (VIP). We found that GAP-43 expression increased 3-fold, peaking between 7 and 14 days after development of the CCI. However, within this same 7-14 day time frame, both CGRP and SP mRNAs fell to half their normally abundant constitutive levels of expression. The most dramatic change in expression occurred for GAL, NPY and VIP mRNAs which all rose rapidly (day 3) from non-detectable levels. Similar alterations in gene expression have been described after complete sciatic nerve transection or crush.

SR13/PMP-22 expression in rat nervous system, in PC12 cells, and C6 glial cell lines

SR13/PMP-22 is a protein that was identified after screening a sciatic nerve cDNA library. Our study focused on comparing the level and pattern of expression of SR13/PMP-22 protein and RNA. Northern blot analysis revealed that although SR13/PMP-22 mRNA was present in all nervous tissues and cells studied, levels were at least seven fold higher in the sciatic nerve and the spinal cord. During sciatic nerve postnatal development and maturation, the SR13/PMP-22 mRNA was detected at 2 days after birth, reached a maximal level at day 24, and decreased to 1/3 of the maximum in adult animals. Nerve transection reduced the level of SR13/PMP-22 mRNA to less than 5% in the segment distal to the nerve injury. Experiments using in situ hybridization localized the SR13/PMP-22 mRNA in Schwann cells. Schwann cells present in the vicinity or distal to the nerve cut repressed the signal for the message. In situ hybridization experiments also demonstrated that dorsal root ganglia satellite cells contained the message for SR13/PMP-22. The SR13/PMP-22 antisera used in our study showed a complex pattern of staining. As expected, the SR13/PMP-22 antibody peptide 1 immunoreacted with the sciatic nerve sheath. However, immunocytochemistry of the dorsal root ganglia revealed that the staining was contained in the neuron's cell body and processes and also in satellite cells. We also identified immunoreactive cell bodies and fibers in the spinal cord dorsal horn. Tissue culture studies demonstrated that SR13/PMP-22 mRNA is induced in NGF treated PC12 but not in C6 glioma cell lines grown under experimental conditions that stimulated cell growth arrest. Our experiments suggest that SR13/PMP-22 may have some other function(s) in addition to its hypothesized role in peripheral myelination.

Quantification of axotomy-induced alteration of neuropeptide mRNAs in dorsal root ganglion neurons with special reference to neuropeptide Y mRNA and the effects of neonatal capsaicin treatment

Alteration in mRNA expression in dorsal root ganglia (DRG) neurons encoding 5 neuropeptides was quantitatively compared in normal rats and in those neonatally treated with capsaicin, a selective neurotoxin which destroys a subpopulation of DRG neurons with unmyelinated axons. Adult rats received a unilateral transection of the sciatic nerve and were killed 7 days later. Oligonucleotide probes specific for the genes encoding neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), galanin (GAL), somatostatin (SOM), and calcitonin gene-related peptide (CGRP) were used for in situ hybridization and RNA blot analysis. Following the nerve cut, RNA blot analysis demonstrated a dramatic induction of NPY, VIP, and GAL mRNA levels from the undetectable constitutive level of expression. Conversely, CGRP and SOM mRNAs, which are constitutively expressed, were reduced 55% and 70%, respectively, following the nerve cut. A unimodal size distribution for neurons expressing NPY mRNA was determined, with a mean cross-sectional area of 1700 microns2 representing 24.4% of DRG neurons ipsilateral to the nerve cut. Neurons expressing VIP mRNA were mainly small sized, with a cross-sectional area of approximately 700 microns2, while those expressing GAL mRNA were both small (approximately 700 microns2) and medium (approximately 1,300 microns2) sized. The percentages of neurons expressing VIP or GAL mRNA were 19.9% and 33.7%, respectively. In neonatal capsaicin-treated rats, there was a 10% reduction in neurons expressing NPY mRNA, a 37% reduction for VIP, and a 27% for GAL mRNA compared to vehicle-treated rats after nerve cut. Capsaicin-sensitive neurons comprised 37% of CGRP neurons and 83% of SOM neurons. These observations suggest that NPY is primarily induced in myelinated primary afferent neurons, while VIP and GAL mRNA induction occurs in a mixed population, a sizeable percentage of which has unmyelinated axons. Additionally, SOM mRNA expression is associated mainly with unmyelinated primary afferents.

Demonstration of dynorphin A 1–8 immunoreactive axons contacting spinal cord projection neurons in a rat model of peripheral inflammation and hyperalgesia

Using a double-labeling technique, we evaluated the input of afferents immunoreactive for dynorphin peptide onto a population of lumbar spinal neurons contributing to the spinoparabrachial tract in rats with 1 inflamed hind paw. We found that the frequency and distribution with which dynorphin immunoreactive varicosities were in apposition to projection neurons varied according to neuron location. In particular, neurons in the superficial dorsal horn and neck of the dorsal horn receive a high degree of dynorphin input. We also determine that unilateral peripheral inflammation is associated with both an increase in the number of projection neurons receiving detectable DYN input and in the frequency of this input onto a given neuron, with the largest increase seen in the superficial dorsal horn. Since almost all superficial dorsal horn neurons contributing to the spinoparabrachial tract respond either exclusively or maximally to noxious stimulation, our data supports dynorphin's involvement in nociception.