Biomedical subjects

Harold Brem

Publications and source records attributed to Harold Brem.

At least 19 recordsLinked to original sources

PubMed2006

Novel genomic effects of glucocorticoids in epidermal keratinocytes: inhibition of apoptosis, interferon-gamma pathway, and wound healing along with promotion of terminal differentiation.

Glucocorticoids (GCs) have a long history of use as therapeutic agents for numerous skin diseases. Surprisingly, their specific molecular effects are largely unknown. To characterize GC action in epidermis, we compared the transcriptional profiles of primary human keratinocytes untreated and treated with dexamethasone (DEX) for 1, 4, 24, 48, and 72 h using large scale microarray analyses. The majority of genes were found to be regulated only after 24 h and remained regulated throughout treatment. In addition to regulation of the expected pro-inflammatory genes, we found that GCs regulate cell fate, tissue remodeling, cell motility, differentiation, and metabolism. GCs suppress the expression of essentially all IFNgamma-regulated genes, including IFNgamma receptor and STAT-1, an effect that was previously unknown. GCs also block STAT-1 activation and nuclear translocation. Unexpectedly, GCs induce the expression of anti-apoptotic genes and repress pro-apoptotic ones, preventing UV-induced keratinocyte apoptosis. Consequently, treatment with GCs blocked UV-induced apoptosis of keratinocytes. GCs have profound effect on wound healing by inhibiting cell motility and the expression of the proangiogenic factor, vascular endothelial growth factor. They play an important role in tissue remodeling and scar formation by suppressing the expression of TGFbeta1 and -2 and MMP1, -2, -9, and -10 and inducing TIMP-2. Finally, GCs promote terminal epidermal differentiation while simultaneously inhibiting early stage differentiation. These results provide new insights into the beneficial and adverse effects of GCs in the epidermis, defining the participating genes and mechanisms that coordinate the cellular responses important for GC-based therapies.

Apoptosis↗

PubMed2006

Prevention and reversal of diabetic nephropathy in db/db mice treated with alagebrium (ALT-711).

BACKGROUND: Alagebrium (ALT-711) has been shown to improve renal dysfunction in animal models of diabetes. METHODS: To test its effects in diabetic nephropathy (DN), ALT-711 was administered (1 mg/kg daily i.p.) to 9-week-old female db/db mice (n = 15, group A1) for 3 weeks and to 3-month-old (n = 15, group A2), 7-month-old (n = 7, group A3), and 12-month-old (n = 5, group A4) female db/db mice for 12 weeks, while a similar number of diabetic and nondiabetic mice were used as controls. The epsilonN-carboxymethyllysine (CML) levels in serum, urine, skin, and kidney tissue were measured by enzyme-linked immunosorbent assay. The renal morphometric parameters were assessed by electron and light microscopy. RESULTS: By the 3rd week of treatment, the serum CML level decreased by 41%, and the urinary CML concentration increased by 138% from baseline, while the urinary albumin/creatinine ratio was lower (p < 0.05) in diabetic and nondiabetic group A1 mice. After 3 months of treatment, serum, skin, and kidney CML levels and urinary albumin/creatinine ratio were lower (p < 0.05) and the urinary CML levels higher (p < 0.05) in treated group A2, A3, and A4 animals compared with groups which received phosphate-buffered saline, with a similar pattern observed in nondiabetic mice. The renal morphological parameters characteristic of DN decreased in treated compared with untreated mice. CONCLUSION: Alagebrium may prevent, delay, and/or reverse established DN in db/db mice by reducing the systemic advanced glycation end product pools and facilitating the urinary excretion of advanced glycation end products.

Animals↗

PubMed2006

Evidence-based protocol for diabetic foot ulcers.

BACKGROUND: Diabetic foot ulcers are the single biggest risk factor for nontraumatic foot amputations in persons with diabetes. Foot ulcers occur in 12 to 25 percent of persons with diabetes and precede 84 percent of all nontraumatic amputations in this growing population. Because of the high incidence of foot ulcers, amputations remain a source of morbidity and mortality in persons with diabetes. Strict adherence to evidence-based protocols as described herein will prevent the majority of these amputations. METHODS: The collective experience of treating patients with neuropathic diabetic foot ulcers in four major diabetic foot programs in the United States and Europe was analyzed. RESULTS: The following protocol was developed for patients with diabetic foot ulcers: (1) establishment of good communication among the patient, the wound healing team, and the primary medical doctor; (2) comprehensive, protocol-driven care of the entire patient, including hemoglobin A1c, microalbuminuria, and cholesterol as well as early treatment of retinopathy, nephropathy, and cardiac disease; (3) weekly objective measurement of the wound with digital photography, planimetry, and documentation of the wound-healing process using the Wound Electronic Medical Record, if available; (4) objective evaluation of blood flow in the lower extremities (e.g., noninvasive flow studies); (5) débridement of hyperkeratotic, infected, and nonviable tissue; (6) use of systemic antibiotics for deep infection, drainage, and cellulitis; (7) off-loading; (8) maintenance of a moist wound bed; (9) use of growth factor and/or cellular therapy if the wound is not healing after 3 weeks with this protocol; and (10) consideration of the use of vacuum-assisted therapy in complex wounds. CONCLUSIONS: In diabetic foot ulcers, availability of the above modalities, in combination with early recognition and comprehensive treatment, ensures rapid healing, minimizes morbidity and mortality rates, and eliminates toe and limb amputations in the absence of ischemia and osteomyelitis.

Anti-Bacterial Agents↗

PubMed2005

Molecular pathogenesis of chronic wounds: the role of beta-catenin and c-myc in the inhibition of epithelialization and wound healing.

Lack of understanding of the molecular mechanisms and pathogenesis of impaired healing in chronic ulcers is a serious health issue that contributes to excessive limb amputations and mortality. Here we show that beta-catenin and its downstream targets in keratinocytes, c-myc, and keratins K6 and K16, play important roles in the development of chronic wounds. In contrast to normal epidermis, we observed a significant nuclear presence of beta-catenin and elevated c-myc expression at the nonhealing wound edge of chronic ulcers from 10 patients. In vitro studies indicated that stabilization of nuclear beta-catenin inhibited wound healing and keratinocyte migration by blocking epidermal growth factor response, inducing c-myc and repressing the K6/K16 keratins (cytoskeletal components important for migration). The molecular mechanism of K6/K16 repression involved beta-catenin and arginine methyltransferase (CARM-1) acting as co-repressors of glucocorticoid receptor monomers. We conclude that activation of the beta-catenin/c-myc pathway(s) contributes to impaired healing by inhibiting keratinocyte migration and altering their differentiation. The presence of activated beta-catenin and c-myc in the epidermis of chronic wounds may serve as a molecular marker of impaired healing and may provide future targets for therapeutic intervention.

Biomarkers↗

PubMed2005

The book of opposites: the role of the nuclear receptor co-regulators in the suppression of epidermal genes by retinoic acid and thyroid hormone receptors.

Transcriptional regulation by nuclear receptors occurs through complex interactions that involve DNA response elements, co-activators/co-repressors, and histone modifying enzymes. Very little is known about how molecular interplay of these components may determine tissue specificity of hormone action. We have shown previously that retinoic acid (RA) and thyroid hormone (T3) repress transcription of a specific group of epidermal keratin genes through a novel mechanism that utilizes receptors homodimers. In this paper, we have analyzed the epidermal specificity of RA/T3 action by testing the role of co-repressors and co-activators in regulation of epidermal genes. Using transient co-transfections, northern blots, antisense oligonucleotides, and a histone deacetylase (HDAC) inhibitor, trichostatin A, we found that in the context of specific keratin RE (KRE), co-activators and histone acetylase become co-repressors of the RA/T3 receptors in the presence of their respective ligands. Conversely, co-repressors and HDAC become co-activators of unliganded T3Ralpha. The receptor-co-activator interaction is intact and occurs through the NR-box. Therefore, the role of co-activator is to associate with liganded receptors whereas the KRE-receptor interaction determines specific transcriptional signal, in this case repression. This novel molecular mechanism of transcriptional repression conveys how RA and T3 target specific groups of epidermal genes, thus exerting intrinsic tissue specificity.

Carrier Proteins↗

PubMed2004

From an enhanceosome to a repressosome: molecular antagonism between glucocorticoids and EGF leads to inhibition of wound healing.

Wound healing in its complexity depends on the concerted activity of many signaling pathways. Here, we analyzed how the simultaneous presence of glucocorticoids (GC), retinoic acid (RA) and epidermal growth factor (EGF) affect wound healing at the molecular, cellular and tissue levels. We found that GC inhibit wound healing by inhibiting keratinocyte migration, whereas RA does not. Furthermore, GC block EGF-mediated migration, whereas RA does not. On the molecular level, these compounds target expression of one of the earliest markers of wound healing, cytoskeletal components, keratins K6 and K16. Both GC and RA repress their transcription, whereas EGF induces it. Interestingly, the GC inhibition is mediated by a repressosome complex consisting of four monomers of the GC receptor, beta-catenin and coactivator-associated-arginine-methyltransferase-1. GC are dominant, EGF cannot rescue GC-mediated inhibition. Pre-treatment of keratinocytes with GC shifts the balance towards the repressosome, allowing for dominant inhibition of K6 even in the presence of EGF or c-fos/c-jun. Although RA receptor gamma and glucocorticoid receptor bind to the same response element repressing transcription of keratins K6/K16, RA receptor interacts with the components of the EGF-enhanceosome (co-activators: glucocorticoid-receptor-interactive protein-1(GRIP-1)/steroid-receptors coactivator-1 (SRC-1)) without breaking it. Consequently, RA has a co-dominant effect with EGF: when present simultaneously, their effects balance each other. When keratinocytes are pre-treated with mitogen-activated protein kinase (MAPK) inhibitor, thus blocking EGF, the balance is shifted towards the RA repression. Similar to clinical findings, pre-treatment of keratinocytes with RA blocks GC-mediated inhibition. In summary, our results identify complex molecular mechanisms through which RA alleviates GC-mediated inhibition of wound healing.

Base Sequence↗

PubMed2004

Protocol for the successful treatment of venous ulcers.

Venous ulcers affect up to 2.5 million patients per year in the United States. Although not usually fatal, these chronic wounds severely affect patients' quality of life because of impaired mobility and substantial loss of productivity. Although venous ulcers are typically small initially, they are often undertreated, progressing to larger ulcers that are associated with more serious complications requiring more complex treatments. In this report we detail the pathogenesis of venous ulcers together with potential complications, including exudate, erythema, cellulitis, dermatitis, pain, and possible malignancy. The clinician's regimen should always include a wide range of treatment modalities to ensure comprehensive care and effective wound closure. The treatment modalities and specific protocol for venous ulcers are discussed, and include topical dressings, antibiotics, debridement, compression therapy, and cellular therapy. These treatment modalities, in combination with early recognition and regular monitoring using digital photography and planimetry measurements, will ensure rapid healing and minimize complications and cost.

Bandages↗

PubMed2004

Protocol for the successful treatment of pressure ulcers.

Bed-bound patients with pressure ulcers are almost twice as likely to die as are those without pressure ulcers. If pressure ulcers are treated with a comprehensive regimen upon early recognition, nearly all stage IV ulcers can be avoided. Furthermore, such a regimen can significantly reduce the comorbidities, mortalities, and costs of treatments resulting from stage IV ulcers. The costs of treatments for comorbidities after the ulcer progresses to stage IV far outweigh the costs for early treatment of the ulcer before it progresses beyond the early stages. We describe herein the 4 stages of pressure ulcers, as well as the pathogeneses, costs, and complications associated with these wounds. A comprehensive 12-step detailed protocol for treatment of pressure ulcers is described; this includes recognizing that every patient with limited mobility is at risk for developing a sacral, ischial, trochanteric, or heel ulcer; daily assessment of the skin; objective measurement of every wound; immediate initiation of a treatment protocol; mechanical debridement of all nonviable tissue; establishment of a moist wound-healing environment; nutritional supplementation for malnourished patients; pressure relief for the wound; elimination of drainage and cellulitus; biological therapy for patients whose wounds fail to respond to more traditional therapies; physical therapy; and palliative care. Availability of the described treatment modalities, in combination with early recognition and regular monitoring, ensures rapid healing and minimizes morbidity, mortality, and costs.

Aged↗

PubMed2004

Practical treatment of pain in patients with chronic wounds: pathogenesis-guided management.

In addition to its own inherent morbidity, the pain associated with chronic wounds presents a primary obstacle to healing. To initiate safe and effective therapy, we used a multidisciplinary approach that required the wound-healing clinician and pain-management practitioner to work together to diagnose and treat the pain associated with these wounds. This approach emphasizes wound pathophysiology, which facilitates treatment modalities that focus on the cause of the pain as well as more efficient analgesia. All wound patients were approached with the assurance that they should not experience pain. The most important part of pain control is objective assessment and assuring patients that their pain will be resolved. Differential diagnosis is critical (eg, wound pain associated with infection, necrosis, spinal cord injury, neuropathy). We determined that to resolve pain, the following 4 goals must be achieved: (1) removal of all nonviable, locally infected tissue and elimination of all cellulitis; (2) determination of wound pathogenesis; (3) availability of both local and systemic analgesia; and (4) assessment of objective improvement through the periodic use of an analgesic scale. By following this protocol, the wound-healing clinician can expect decreased length of hospital stay and resolution of pain in nearly all patients with wounds.

Aged↗

PubMed2004

Gene array technology and pathogenesis of chronic wounds.

Many of the limitations in treatment of chronic wounds are based on lack of knowledge of the molecular mechanism(s) of wound healing. Furthermore, diagnostic tools in wound healing are still primarily macroscopic, visual, and histologic. Thus, by understanding mechanisms of wound healing at a molecular level, new treatments can be designed, prevention programs developed, and a better understanding of current treatments provided. The ability to methodically analyze the expression patterns of thousands of genes simultaneously allows for identification of groups of molecular defects that lead to chronic inhibition of the wound-healing process. Gene array technology is having a major impact on the field of wound healing and has the potential to profoundly affect the way we understand the pathogenesis, diagnosis, prevention, and treatment of chronic wounds. Currently, gene array technology is used in the field of chronic wound healing to (1) understand the pathogenesis of pressure ulcers and venous ulcers, (2) understand the pathogenesis of diabetic foot ulcers, including the role that neuropathy may play in delayed healing of diabetic foot ulcers, and (3) determine the mechanism(s) of established and new local treatments, that is, pharmacogenomics for pressure ulcers and diabetic foot ulcers.

Chronic Disease↗

PubMed2004

Statistical analysis of wound-healing rates for pressure ulcers.

To establish a functional model for determining wound-healing rates to use in the evaluation of efficacy of wound therapies, a review was conducted of statistical analysis methods from past wound-healing studies. Because most wounds do not usually close within the period of observation, that is, 12 weeks, evaluating time to 100% closure is not practical. Thus, a new, practical model for statistical analysis was formulated. A Gompertz-like function was applied to wound-healing rates of pressure ulcers, in the context of repeated measures for a nonlinear model. Photographing the wounds weekly, tracing their area with planimetry, and applying this new statistical model allows for the calculation of the expected rate of healing as a function of time. This approach yields a model useful for identifying prognostic factors, evaluating treatments, and improving our understanding of the variables that affect the wound-healing process.

Body Weights and Measures↗

PubMed2004

Protocol for treatment of diabetic foot ulcers.

Each year, 82,000 limb amputations are performed in patients with diabetes mellitus. The majority of these amputations could be avoided by following strict protocols. The collective experience treating patients with neuropathic diabetic foot ulcers of 4 major diabetic foot programs in the United States and Europe were analyzed. The following protocol has been developed for patients with diabetic foot ulcers: (1) measurement of the wound by planimetry; (2) optimal glucose control; (3) surgical debridement of all hyperkeratotic, infected, and nonviable tissue; (4) systemic antibiotics for deep infection, drainage, and cellulitis; (5) offloading; (6) moist-wound environment; and (7) treatment with growth factors and/or cellular therapy if the wound is not healing after 2 weeks with this protocol and a new epithelial layer is not forming. In addition, the pathogenesis of diabetic foot ulcers is discussed, as well as the associated costs and complications, including amputation. Debridement, wound-bed preparation, antibiotics, various types of dressings, biological therapies, growth factors, and offloading are described as treatment modalities for patients with diabetic foot ulcers. In diabetic foot ulcers, availability of the above modalities, in combination with early recognition and comprehensive treatment, ensure rapid healing and minimize morbidity, mortality, and costs, as well as eliminate amputation in the absence of ischemia and osteomyelitis.

Biological Therapy↗

PubMed2003

Adverse effects of dietary glycotoxins on wound healing in genetically diabetic mice.

Advanced glycoxidation end products (AGEs) are implicated in delayed diabetic wound healing. To test the role of diet-derived AGE on the rate of wound healing, we placed female db/db (+/+) (n = 55, 12 weeks old) and age-matched control db/db (+/-) mice (n = 45) on two diets that differed only in AGE content (high [H-AGE] versus low [L-AGE] ratio, 5:1) for 3 months. Full-thickness skin wounds (1 cm) were examined histologically and for wound closure. Serum 24-h urine and skin samples were monitored for N(epsilon)-carboxymethyl-lysine and methylglyoxal derivatives by enzyme-linked immunosorbent assays. L-AGE-fed mice displayed more rapid wound closure at days 7 and 14 (P < 0.005) and were closed completely by day 21 compared with H-AGE nonhealed wounds. Serum AGE levels increased by 53% in H-AGE mice and decreased by 7.8% in L-AGE mice (P < 0.04) from baseline. L-AGE mice wounds exhibited lower skin AGE deposits, increased epithelialization, angiogenesis, inflammation, granulation tissue deposition, and enhanced collagen organization up to day 21, compared with H-AGE mice. Reepithelialization was the dominant mode of wound closure in H-AGE mice compared with wound contraction that prevailed in L-AGE mice. Thus, increased diet-derived AGE intake may be a significant retardant of wound closure in diabetic mice; dietary AGE restriction may improve impaired diabetic wound healing.

Administration, Oral↗

PubMed2003

Clinical efficacy and mechanism of bilayered living human skin equivalent (HSE) in treatment of diabetic foot ulcers.

UNLABELLED: Bilayered living human skin equivalent (HSE) consists of cultured keratinocytes residing on the surface of a fibroblast-populated collagen lattice. Although HSE is FDA-approved for treatment of diabetic foot and venous stasis ulcers, its clinical efficacy remains limited, because the molecular mechanisms underlying its therapeutic effect are not fully understood. It is, therefore, often applied mistakenly as a skin graft. In this report, we delineate a mechanism of HSE biological effect and consequent optimal clinical use in accelerating closure of diabetic foot ulcers. EXPERIMENTAL: HSE was grafted onto nude mice and the release of various growth factors was evaluated by reverse transcription-polymerase chain reaction (RT-PCR) and immunochemistry. Clinical: HSE was grafted onto 11 consecutive patients with diabetes who had 13 non-ischemic foot ulcers and healing was measured as time to 100% closure (e.g., no drainage and 100% epithelialized). EXPERIMENTAL: HSE cellular components were determined to express 15 different growth factors/cytokine genes known to promote wound healing. Histological evidence from the nude mice showed that the collagen component of HSE underwent remodeling within the first seven days of grafting. Clinical: All diabetic foot ulcers healed in 31.8 12.4 days. Local release of a unique combination of 15 growth factors expressed by HSE keratinocyte and fibroblast components generates closure of diabetic foot ulcers. HSE should be applied with the same surgical conditions for a skin graft (i.e., no cellulitis, no drainage, and negligible bacteria). We hypothesize that bilayered HSE generates its effect by way of the local synthesis and release of multiple growth factors in specific combination and concentration, which improves the impaired reparative process of chronic wounds.

Animals↗

PubMed2003

Wound-healing protocols for diabetic foot and pressure ulcers.

Diabetic foot and pressure ulcers are chronic wounds by definition. They share similar pathogeneses; i.e., a combination of increased pressure and decreased angiogenic response. Neuropathy, trauma, and deformity also often contribute to development of both types of ulcers. Early intervention and proper treatment should result in complete healing of non-ischemic diabetic foot and pressure ulcers, as defined by 100% epithelialization and no drainage (if no osteomyelitis is present). The authors developed the following paradigm, which has proved to be highly effective for complete healing of these wounds: 1) recognition that all patients with limited mobility are at risk for a sacral, ischial, trochanteric, or heel pressure ulcer; 2) daily self-examination of the sacral, ischium, buttocks, hips, and heels of all bed-bound patients and the feet of patients with diabetes with risk factors (e.g., neuropathy); 3) initiation of a treatment protocol immediately upon recognition of a break in the skin (i.e., emergence of a new wound); 4) objective measurement by planimetry of every wound (at a minimum, weekly) and documentation of its progress; 5) establishment of a moist wound-healing environment; 6) relief of pressure from the wound; 7) debridement of all non-viable tissue in the wound; 8) elimination of all drainage and cellulitis; 9) cellular therapy or growth factors for patients with wounds that do not heal rapidly after initial treatment; and 10) continuous physical and psychosocial support for all patients. If this paradigm is followed, most diabetic foot and pressure ulcers are expected to heal.

Acute Disease↗

PubMed2003

Healing of elderly patients with diabetic foot ulcers, venous stasis ulcers, and pressure ulcers.

Although elderly patients have physiologic impairments in wound healing, their wounds should be expected to heal with the same frequency of closure as those in younger populations, albeit at a slower rate. However, compared to the general population, the elderly population has a higher incidence of chronic wounds: diabetic foot ulcers, pressure ulcers, and venous stasis ulcers. Experimental and clinical data indicate physiologically impaired healing is characterized by decreased angiogenesis and synthesis of critical growth factors. Further, compared to younger populations, the elderly have a higher rate of mortality associated with specific morbidities, such as sepsis and acute respiratory distress. As these morbidities may develop directly from the wound, early intervention is mandated. In this report, 40 consecutive elderly patients (65-102 years old) with chronic wounds were analyzed. All patients were provided the same treatment protocol and healing was defined as 100% epithelization and no drainage. Despite the wounds presenting in a nonhealing and/or infected state, 73% of these chronic wounds in elderly patients healed. This suggests that elderly patients with diabetic foot ulcers, pressure ulcers, and venous stasis ulcers close their wounds at a similar frequency as younger patients. Therefore, early intervention and comprehensive treatment that includes safe topical therapies, in addition to growth factors and cellular therapy used for chronic wounds, ensure these patients will be spared the morbidities of pain, amputation, osteomyelitis, and even death. We hypothesize that if all elderly patients with chronic wounds are provided early treatment, morbidities (e.g., amputation, sepsis, pain) and associated costs will decrease.

Age Factors↗

PubMed2003

Pathogenesis and treatment of pain in patients with chronic wounds.

Pain must be managed during treatment of a patient with a chronic wound. Failure to do so will impair the patient's ability to heal significantly. Understanding the wound's etiology is essential for designing the wound-healing protocol and implementing its pain management regimen, of which a critical part is the chronic-wound patient's self-assessed scores of pain and functionality. In this report we present a paradigm for treating all chronic wounds, which was subsequently applied to 32 consecutive patients. Our integrated-team approach to managing the treatment of wounds includes accurate evaluation of the progression of patients' pain. Directors of the pain-management team and wound team have jointly managed hundreds of patients--either hospitalized or seen in both outpatient clinical practices. The three general categories for etiologies of the 10 most common types of chronic wounds are: ischemia, neuropathy, and direct tissue damage (e.g. pressure ulcers and venous stasis ulcers). Each of these are treated with unique analgesic regimens focused on surgical/medical management of the wound: oral and parenteral medications in combinations designed to facilitate specific additive analgesic effects and nerve blocks and implantable devices for correcting underlying wound pathophysiology. Successful treatment of pain generally results in increased functional independence and improvement of the patient's quality of life. We integrated wound-care pain-management team established guidelines that delineate the causes of chronic wounds and categorize treatment options for practical clinical use. The expectation is that all pain should be resolved in all patients if both the wound-healing and pain-healthcare providers use current technologies and drugs.

Analgesics↗

PubMed2002

Pressure ulcers in the chronically critically ill patient.

All chronically critically ill patients are at high risk for development and progression of pressure ulcers. Constant surveillance including daily examination of the skin must be part of the care protocol. All pressure ulcers are chronic wounds that have an inherent, physiologic impairment to healing. As soon as a pressure ulcer develops, intervention should begin immediately, and a treatment plan should be determined. We believe that early intervention and appropriate treatment, guided by the paradigm we have described, can retard progression and promote healing [49]. Treatment decisions should be made within the context of the patient's overall care goals.

Chronic Disease↗