TREM2 is thyroid hormone regulated making the TREM2 pathway druggable with ligands for thyroid hormone receptor

Triggering receptor expressed on myeloid cells-2 (TREM2) is a cell surface receptor on macrophages and microglia that senses and responds to disease-associated signals to regulate the phenotype of these innate immune cells. The TREM2 signaling pathway has been implicated in a variety of diseases ranging from neurodegeneration in the central nervous system to metabolic disease in the periphery. Here, we report that TREM2 is a thyroid hormone-regulated gene and its expression in macrophages and microglia is stimulated by thyroid hormone and synthetic thyroid hormone agonists (thyromimetics). Our findings report the endocrine regulation of TREM2 by thyroid hormone, and provide a unique opportunity to drug the TREM2 signaling pathway with orally active small-molecule therapeutic agents.

TREM2 is thyroid hormone regulated making the TREM2 pathway druggable with ligands for thyroid hormone receptor

Triggering receptor expressed on myeloid cells-2 (TREM2) is a cell surface receptor on macrophages and microglia that senses and responds to disease associated signals to regulate the phenotype of these innate immune cells. The TREM2 signaling pathway has been implicated in a variety of diseases ranging from neurodegeneration in the central nervous system to metabolic disease in the periphery. We report here that TREM2 is a thyroid hormone regulated gene and its expression in macrophages and microglia is stimulated by thyroid hormone. Both endogenous thyroid hormone and sobetirome, a synthetic thyroid hormone agonist drug, suppress pro-inflammatory cytokine production from myeloid cells including macrophages that have been treated with the SARS-CoV-2 spike protein which produces a strong, pro-inflammatory phenotype. Thyroid hormone agonism was also found to induce phagocytic behavior in microglia, a phenotype consistent with activation of the TREM2 pathway. The thyroid hormone antagonist NH-3 blocks the anti-inflammatory effects of thyroid hormone agonists and suppresses microglia phagocytosis. Finally, in a murine experimental autoimmune encephalomyelitis (EAE) multiple sclerosis model, treatment with Sob-AM2, a CNS-penetrating sobetirome prodrug, results in increased Trem2 expression in disease lesion resident myeloid cells which correlates with therapeutic benefit in the EAE clinical score and reduced damage to myelin. Our findings represent the first report of endocrine regulation of TREM2 and provide a unique opportunity to drug the TREM2 signaling pathway with orally active small molecule therapeutic agents.

Thyroid hormone and thyromimetics inhibit myelin and axonal degeneration and oligodendrocyte loss in EAE

We have previously demonstrated that thyromimetics stimulate oligodendrocyte precursor cell differentiation and promote remyelination in murine demyelination models. We investigated whether a thyroid receptor-beta selective thyromimetic, sobetirome (Sob), and its CNS-targeted prodrug, Sob-AM2, could prevent myelin and axonal degeneration in experimental autoimmune encephalomyelitis (EAE). Compared to controls, EAE mice receiving triiodothyronine (T3, 0.4 mg/kg), Sob (5 mg/kg) or Sob-AM2 (5 mg/kg) had reduced clinical disease and, within the spinal cord, less tissue damage, more normally myelinated axons, fewer degenerating axons and more oligodendrocytes. T3 and Sob also protected cultured oligodendrocytes against cell death. Thyromimetics thus might protect against oligodendrocyte death, demyelination and axonal degeneration as well as stimulate remyelination in multiple sclerosis.

Myelin repair stimulated by CNS-selective thyroid hormone action

Oligodendrocyte processes wrap axons to form neuroprotective myelin sheaths, and damage to myelin in disorders, such as multiple sclerosis (MS), leads to neurodegeneration and disability. There are currently no approved treatments for MS that stimulate myelin repair. During development, thyroid hormone (TH) promotes myelination through enhancing oligodendrocyte differentiation; however, TH itself is unsuitable as a remyelination therapy due to adverse systemic effects. This problem is overcome with selective TH agonists, sobetirome and a CNS-selective prodrug of sobetirome called Sob-AM2. We show here that TH and sobetirome stimulated remyelination in standard gliotoxin models of demyelination. We then utilized a genetic mouse model of demyelination and remyelination, in which we employed motor function tests, histology, and MRI to demonstrate that chronic treatment with sobetirome or Sob-AM2 leads to significant improvement in both clinical signs and remyelination. In contrast, chronic treatment with TH in this model inhibited the endogenous myelin repair and exacerbated disease. These results support the clinical investigation of selective CNS-penetrating TH agonists, but not TH, for myelin repair.

Sex-dependent treatment of chronic EAE with partial MHC class II constructs

Background

One of the main challenges in treating multiple sclerosis (MS) is reversing the effects of accumulated damage in the central nervous system (CNS) of progressive MS subjects. While most of the available drugs for MS subjects are anti-inflammatory and thus are limited to relapsing-remitting MS subjects, it is not clear to what extent their effects are capable of inducing axonal repair and remyelination in subjects with chronic MS.

Methods

A chronic model of experimental autoimmune encephalomyelitis (EAE) was used to evaluate the potency of partial MHC (pMHC) class II constructs in treating progressive EAE.

Results

We demonstrated an estrogen receptor alpha (ERα)-dependent increased dose requirement for effective treatment of female vs. male mice using pMHC. Such treatment using 100-μg doses of RTL342M or DRα1-mMOG-35-55 constructs significantly reversed clinical severity and showed a clear trend for inhibiting ongoing CNS damage, demyelination, and infiltration of inflammatory cells into the CNS in male mice. In contrast, WT female mice required larger 1-mg doses for effective treatment, although lower 100-μg doses were effective in ovariectomized or ERα-deficient mice with EAE.

Conclusions

These findings will assist in the design of future clinical trials using pMHC for treatment of progressive MS.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-017-0873-y) contains supplementary material, which is available to authorized users.

The small group consensus process for changing physician practices: influenza vaccination

OBJECTIVE

To evaluate the effectiveness of a small group consensus process in enhancing compliance with guidelines for influenza vaccination among older HMO members.

DESIGN

A controlled study of the practice of primary care physicians, with pre/post comparisons and a 2-year follow-up.

SETTING

An 84,000 member prepaid staff model HMO group practice.

PARTICIPANTS

Primary care clinicians (N = 36) practicing in a staff model HMO.

INTERVENTION

A small-group process, including opinion leader, feedback, and group decision making.

MAIN OUTCOME MEASURE

Percentage of patients in a given physician-panel who received influenza immunization.

RESULTS

Improvement in vaccination rate from 60.8% to 72.35% (with further increases over 2 successive years), in the intervention group as compared with improvement in the control from 60.7% to 65.93%.

CONCLUSION

In this model, the small group consensus process resulted in an alteration in physician practice pattern, yielding a significant improvement in immunization rates above the already-established level of 60%.

Enhancing physician adoption of practice guidelines. Dissemination of influenza vaccination guideline using a small-group consensus process

BACKGROUND

A dissemination intervention to facilitate adoption of a preventive practice guideline (influenza vaccination for older adults) in group practices was developed and evaluated. The intervention, small-group consensus process, started with a physician expert presenting the guideline and followed with the group participating in a structured discussion of ways to implement the guideline that culminated in a public commitment (ie, "buy in") to adopt the guideline.

METHODS

Thirteen group practices and their primary care physicians (mean size, 5) were assigned randomly to intervention or control arms. In each group practice, physicians in the intervention arm met for 1 hour. Control physicians participated in an unrelated discussion (non-steroidal drug use). Guideline adoption was determined by changes in physicians' vaccination rates that were obtained through prechart and postchart reviews of 51 physicians. Prequestionnaires and postquestionnaires measured influenza knowledge and prevention attitudes.

RESULTS

Using analysis of covariance, the small-group consensus process was found to increase physician vaccination rates by 34% compared with the control arm (F (1,48) = 19.49). All intervention arm physicians increased vaccination rates from before to after compared with 54% of control arm physicians. Attitudes and knowledge did not change and were unrelated to increased vaccination rates.

CONCLUSIONS

A case is made for the small-group consensus process as an effective utilization-focused dissemination method. Interventions based on group dynamics and sensitive to local practice contexts can be useful in facilitating adoption of guidelines by physicians in group practices.

Geriatric issues in the diagnosis and management of patients with rheumatic disorders

The musculoskeletal diseases account for the most frequent complaints among older persons. Rarely is it possible to provide the patient with complete symptomatic relief. Instead, the patient needs to be taught good health habits, good concepts of preventive care, the value of rehabilitation, the gains to be achieved through non-pharmacologic therapy, and a recognition that symptoms reflect emotional problems as well as diseased musculoskeletal tissue. Most important, the patient needs to be taught that he or she can live a full exciting life despite the limitations imposed by the musculoskeletal disease. Encouragement of this attitude and institution of any and all measures that will enhance the patient's ability to retain independence are the major components of ongoing care for this growing segment of our population.

Cardiovascular, neuromuscular, and metabolic alterations with age leading to frailty

As members of our society live longer, a greater percentage of the population will be older. These demographic changes will stress our social and medical delivery system, unless interventions can alter the course leading to frailty. Maximal aerobic power decreases with age, due to a decrease in cardiac output, and is exacerbated by cardiovascular disease. Asymptomatic aging does not reduce cardiovascular function to an extent that would lead to loss of function. Metabolism, endurance, and contraction velocity and muscle strength remain relatively high until 40, 50, and 60 years of age, respectively. After age 60, there are dramatic decreases (approximately 10% per year) which lead to loss of function and independence. The loss of muscle function leads to an increase in the likelihood of falls (approximately 4-fold). Exercise programs utilizing "aerobic" exercise activities do not lead to an increase in muscle function, whereas programs designed specifically for muscle can increase function and, presumably, reduce the risk of falls and injuries.

Gender of physicians and patients and preventive care for community-based older adults

BACKGROUND

This study was undertaken to determine whether the gender of patients and physicians is a significant factor in deciding which older adults are offered preventive care.

METHODS

A survey of medical records of ambulatory patients older than 60 years was performed in the practices of 210 physicians. Documentation of influenza vaccine, rectal examination, fecal occult blood test, Papanicolaou smear, pelvic examination, breast examination, mammogram, and pneumococcal vaccine was recorded, and rates of compliance were evaluated by sex of patient and physician.

RESULTS

The medical records of 3327 patients were surveyed. Men were given influenza and pneumococcal vaccines more frequently than women. Among physicians, women physicians were more likely to give influenza vaccine (P = 0.003) and to check for fecal occult blood (P < 0.001). No significant difference was found between men and women physicians in the frequency of doing Papanicolaou smears, breast examinations, rectal examinations, and mammograms.

CONCLUSIONS

While a difference in practice patterns was found between men and women physicians, most of the variance in compliance with preventive care guidelines was unexplained by the gender of physicians and patients. Matching of physician and patient by sex did not predict improved preventive care, indicating that other factors are involved in the failure to provide adequate primary preventive care to the ambulatory elderly.

Forequarter amputation wound coverage with an ipsilateral, lymphedematous, circumferential forearm fasciocutaneous free flap in patients undergoing palliative shoulder-girdle tumor resection

Closure of massive soft-tissue defects in patients undergoing forequarter amputation for shoulder-girdle tumors may present a daunting challenge. This report describes two patients whose forequarter amputations were closed using ipsilateral, lymphedematous, circumferential forearm fasciocutaneous free flaps.

Muscle rehabilitation: its effect on muscular and functional performance of patients with knee osteoarthritis

Muscle function and functional performance are limited in patients with osteoarthritis (OA). Although aerobic exercise can increase aerobic power and reduce fatigue, it does not appear to improve muscle function. The purpose of this study was to demonstrate the effect of a muscle rehabilitation program on muscle strength, endurance, speed, and function for patients with OA of the knees. Fifteen men (67.6 +/- 6.1 years) with OA of the knees underwent a four-month exercise program, three times per week. Muscle strength, endurance, and speed were 50% less in OA patients than in controls. After rehabilitation, there was a significant increase in strength (35%), endurance (35%), and speed (50%). Deficiencies and improvements in the muscles were greater at longer muscle lengths. Increases in muscle function were associated with decreased dependency (10%), difficulty (30%), and pain (40%). The average increase in all measured parameters was 10% and 25% after two and four months of rehabilitation, respectively. Improvements were sustained for eight months after rehabilitation. The muscle rehabilitation program was designed specifically to improve function; the improved muscle function was translated into improved functional performance.

Muscle rehabilitation in impaired elderly nursing home residents

Based on observations of changes in muscle function associated with aging, and the exacerbation of these changes with frailty, a program of muscle strengthening has been developed to correct specific defects in muscles. This pilot study was undertaken on 18 functionally impaired nursing home residents (age range 60 to 90 years) with markedly deteriorated muscle function (50%) secondary to age, disuse, and multiple chronic illnesses. Fourteen of the subjects completed the six-week program without adverse effects. In 75% of the patients, there was improved muscle function, with endurance, strength, and speed increasing 35%, 15%, and 10%, respectively. After the program, many subjects increased their spontaneous activity and decreased their dependency. The improvements were still evident four months after rehabilitation. These results suggest that it may be possible, through a carefully supervised, short-term program of muscle rehabilitation, for nursing home residents to achieve an enhanced level of physical functioning.

The hierarchical structure of geriatric patient satisfaction. An Older Patient Satisfaction Scale designed for HMOs

This paper describes an instrument design effort aimed at measuring patient-satisfaction among older (65 years and over) subscribers of HMOs. The study was conducted in a multi-satellite prepaid group practice in Buffalo, New York. In order to be able to construct a satisfaction measure that would reflect the interests of the actual consumers of HMO-services, a series of four focused group interviews were held with 24 randomly selected elderly enrollees. The substantive content of these interviews was systematically analyzed for both topics and ideas, yielding a total of 173 distinct ideas about the perceived satisfaction with the services received expressed over 3,176 lines of narrative. From this substantive pool, sixty attitudinal statements were constructed with the ideas represented in these statements being proportional to the number of lines of transcribed discussion devoted to each topic. This 60-item Older Patient Satisfaction Scale (OPSS) was submitted to a systematic sample of 229 elderly HMO subscribers. They also were asked to complete two existing scales: the Ware PSQ, and the Larsen CSQ-8. Factor analysis performed on the OPSS-items yielded 14 primary factors of geriatric patient satisfaction, two second-order and one third order general factor. As the second-order factors accounted for the largest proportion of the common variance, those items of the original 60-item OPSS were identified that had highest loadings on these second-order factors, yielding 7 such items for one and 5 for the other. These scales had alpha-reliabilities of .83 and .80, respectively. It was also found that the OPSS had good convergent validity with the PSQ and CSQ-8. The overall psychometric properties identified for the OPSS, as well as the fact that it was constructed from a health-care consumer's perspective, makes it well suited for use with a unique and rapidly expanding geriatric patient population.

Nutritional assessment of community-living well elderly

Nutritional assessment parameters were studied in a sample of 132 community-living well elderly. Results are presented for biochemical parameters of serum albumin, hemoglobin, and total lymphocyte count and anthropometric parameters of height, weight, mid-arm circumference, and triceps skinfold. The data show that, although there are some differences between age groups (young-old and old-old), all values remain well within normal limits established for younger individuals.

Use of a structured functional assessment format in a geriatric consultative service

Interdisciplinary team assessment may not be feasible in the consultative setting because of scarce institutional resources. We explored the extent to which a physician-administered multifaceted assessment could meet the needs of a geriatric consultative service and also provide for the comprehensive functional assessment of elderly patients. Fifty-one consecutive patients, mean age 78, were evaluated. Domains measured included physical and mental health, socioeconomic resources, and activities of daily living. Despite a majority of consult requests for transfer of seemingly stable patients, unrecognized remediable problems were identified in most cases. Compliance with the consultant's recommendations was consistently poor, averaging less than 33% for all of the domains assessed. Nine of the study patients subsequently were transferred to the care of an interdisciplinary team on the geriatric assessment unit. Numbers and types of problems identified by the geriatric consultation using a structured assessment format allows for the comprehensive and efficient disclosure of pertinent management issues. Improved compliance with consultant recommendations may be effected by better education of care providers to the special needs of the geriatric population.

Conducting clinical research in geriatric populations

Clinical research on geriatric populations requires adaptation of traditional methodologies, modification of expectations, and the development of new procedures. Some aspects of research methodology are unique to studies of geriatric populations. Experience in this relatively new area of geriatric research indicates that new partnerships between researchers and long-term care providers are needed. These new relationships require an understanding of the needs of geriatric populations and of the differences between providers of long-term care and of acute-care. Researchers must consider heterogeneity of the population, the probability of multiple diagnoses and treatments, subject attrition, and the possibility of invalid data. Such considerations require extra staff, more time, and increased funding as well as new thinking about study design and protocol implementation.

Effects of intralymphatic immunotherapy on natural killer activity in malignant melanoma patients

Adjuvant immunotherapy has the theoretical attraction of augmenting the host immune response at a time when the tumor burden is low. We have previously reported that intralymphatic immunotherapy (ILI) augments the cytolytic humoral immune responses in melanoma patients. This study was undertaken to assess the effects of ILI on cell-mediated immunity. As a model for the cellular effects of ILI, we investigated the natural killer (NK) cell activity in malignant melanoma patients. Fourteen patients were given an allogeneic cultured tumor cell vaccine (TCV) intralymphatically with concomitant administration of BCG. Natural killer cell activity was assessed sequentially using the single cell lysis and binding assay. Overall NK activity against the K562 target cell line showed a moderate increase over pretreatment levels as reflected by the increased number of target binding lymphocytes. However, the percentage of target binders mediating cell lysis remained unchanged during treatment. Assessment of NK activity against the NK-resistant M14 melanoma cell line reflected similar findings. These results suggest the activation of NK cells by tumor antigens, BCG, and/or alloimmunization with TCV. This increase appears to be manifested by increased target recognition rather than by alterations in effector cell function.

Rheumatic diseases in the elderly. Finding a way through the maze

The manifestations of rheumatic disease in the elderly present a confusing array of diagnoses to the primary care physician. Helpful guidelines in pursuing a definitive diagnosis are outlined, with special mention of three rheumatic conditions (pseudogout, polymyalgia rheumatica, and temporal arteritis) which are uniquely characteristic of elderly patients.

Medical student attitudes toward geriatric medicine and patients

This study examines the influence of factual knowledge of the aged, general attitudes toward the aged, and personal contact with the aged on first-year medical students' attitudes toward geriatric patients and geriatric medicine. Entering medical students indicated a preference for working with younger patients rather than aged patients. Students' attitudes toward the aged were associated positively with their knowledge of the aged, but their interest in geriatric medicine did not appear to be affected significantly by knowledge of, attitudes toward, or personal contact with the aged. The results suggest that factors beyond those considered in this study may need to be examined if there is to be an increase in the number of physicians wishing to care for the elderly.

Potassium permanganate reaction in amyloidosis. A histologic method to assist in differentiating forms of this disease

A simple and reproducible histochemical method for distinguishing different chemical types of amyloid is described. The method is based on the affinity of amyloid for Congo red dye after exposure to potassium permangenate and dilute sulfuric acid. The permanganate method represents a modification of the Romhanyi trypsin technique. It yields comparable results while obviating some of the technical difficulties associated with the latter method. The permanganate reaction was applied to a series of amyloid samples of known amino acid composition, to amyloid samples fixed in a variety of different preservatives, and to tissues obtained at autopsy from 67 amyloidosis patients whose disease had been previously subclassified on the basis of clinical presentation and autopsy observations. This method distinguished amyloid protein AA from other varieties of amyloid and proved effective when applied to amyloid samples preserved in any of several commonly used fixatives. This simple histochemical method proved useful in subclassifying amyloid type in the patient series particularly when used in conjunction with the available clinical history and the organ distribution of amyloid accumulation.

Amyloid in the aged heart: frequency and clinical significance

Cardiac amyloid accumulation is a common autopsy finding in elderly persons, the frequency increasing with each advancing age decade. In most cases the deposits are microscopic, confined to the atrial subendocardium, and of dubious significance. In a few cases, however, there is much more extensive cardiac involvement, with infiltration of the ventricular musculature and intracardiac conduction system. In the authors' recent autopsy study of 100 patients over 60 years of age, 10 had diffuse cardiac amyloidosis with biventricular involvement. Microscopically, the amyloid deposits often resembled foci of interstitial fibrosis. Significant cardiac enlargement (weight greater than 380 gm) was present in only 2 of these patients, and in only one of them were the clinical signs and symptoms clearly attributable attributable to the amyloid infiltration. It was difficult to assess the possible contribution of ventricular amyloid to congestive failure since most of the patients also had coronary arteriosclerosis. In the aged, clinically significant cardiac amyloidosis associated with cardiac enlargement appears to be part of a disease spectrum more commonly characterized by focal, clinically insignificant cardiac amyloid deposits. Yet several features suggest that senile cardiac amyloidosis may differ from the clinically significant cardiac amyloidosis occassionally seen in younger patients.

The isolation and identification of the P-component of normal human plasma proteins

A normal human plasma protein called the P-component, which has a reaction of identity with the pentagonal structure found in amyloid-laden organs, has been isolated and identified with a recently characterized protein, the 9.5S alpha(1)-glycoprotein.

Antigenic components of human amyloid

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