Surgical stress inhibits the growth of fibroblasts through the elevation of plasma catecholamine and cortisol concentrations

Serum collected from rats with myocardial infarction increases extracellular matrix accumulation by myofibroblasts isolated from myocardial infarction scar

The effect on extracellular matrix content is believed to be an average of several serum derived compounds acting in opposition. The aim of the study is to determine whether whole serum of rats with myocardial infarction may modify the accumulation of extracellular matrix in cultures of myofibroblasts isolated from the myocardial infarction scar. A second aim is to determine whether the tested serum can also degranulate the mast cells. Serum was collected from rats with sham myocardial infarction, rats with myocardial infarction induced by coronary artery ligation and control animals. The experiments were carried out on myocardial infarction scar myofibroblasts or mast cells from the peritoneal cavity. The cultures were divided into three groups containing eight cultures each: one treated with serum from control rats, from animals after sham operation or from those after myocardial infarction. In all groups, the serum was used at concentrations of 10%, 20% or 30%. The total collagen content (Woesner method) glycosaminoglycan level (Farandale method), cell proliferation (BrdU), histamine secretion from mast cells (spectrofluorymetry), β1 integrin and α-smooth muscle actin expression (flow cytometry) were evaluated. Isolated cells were α-smooth muscle actin positive and identified as myofibroblasts. Serum derived from rats with myocardial infarction increased collagen and glycosaminoglycan content in the cultures and modified myofibroblast proliferation in a concentration-dependent manner. The serum also results in an imbalance between collagen and glycosaminoglycan levels. The content of β1 integrin was not influenced by myocardial infarction serum. The serum of rats with myocardial infarction is involved in regulation of collagen and glycosaminoglycan content in myofibroblast cultures, as well as the modification of their proliferation. These changes were not accompanied with integrin β1 density variations. The serum of the myocardial infarction rats did not influence the mast cell degranulation.

Continuous Glucose Monitoring in Bariatric Patients Undergoing Laparoscopic Sleeve Gastrectomy and Laparoscopic Roux-En-Y Gastric Bypass

BACKGROUND

Few investigations have been conducted that compared blood glucose in patients with diabetes mellitus (DM2) and morbid obesity who had undergone laparoscopic sleeve gastrectomy (LSG) or gastric bypass (LRYGB). We aimed to compare the effects of these procedures using continuous glucose monitoring (CGM).

METHODS

We prospectively studied patients that had qualified for LSG or LRYGB. The inclusion criteria were DM2 of ≤ 5 years, for which patients were taking oral anti-diabetic drugs, or no glucose metabolism disorder; and morbid obesity. CGM was performed between admission and the 10th postoperative day.

RESULTS

We studied 16 patients with DM2 and 16 without. Eighteen patients underwent LSG and 14 underwent LRYGB. The median hemoglobin A1c was 5.5% (5.4-5.9%) in DM2 patients, which did not differ from control (p = 0.460). Preoperative mean daily glucose concentration was similar between DM2 and control patients (p = 0.622). For patients with DM2, LRYGB was associated with more frequent low glucose status, and these episodes lasted longer than in DM2 patients that underwent LSG (p = 0.035 and 0.049, respectively). DM2 patients that underwent LRYGB demonstrated lower glucose concentrations from third postoperative day than those that underwent LSG. Patients without DM2 did not demonstrate differences in daily mean glucose concentrations, or in incidence nor duration of hypoglycemia throughout the observation period.

CONCLUSION

A significantly larger reduction in interstitial glucose concentration is present from third day in patients with DM2 who undergo LRYGB vs. LSG, accompanied by a lower incidence and shorter duration of low glucose episodes.

The impact of stress on epidermal barrier function: an evidence-based review

BACKGROUND

The epidermal barrier functions to limit skin infection and inflammation by inhibiting irritant and immunogen invasion. Abundant evidence suggests that psychological stress stemming from crowding, isolation, nicotine smoking, insomnia, mental arithmetic tasks, physical pain, real-life stressors (examinations and marital strain) and lack of positive personality traits may impart both acute and chronic epidermal dysfunction.

OBJECTIVES

To review the relationship between stress and epidermal barrier dysfunction.

METHODS

A review of the PubMed and Embase databases was conducted to identify all English-language case-control, cross-sectional and randomized control trials that have reported the effect of stress on epidermal barrier function. The authors' conclusions are based on the available evidence from 21 studies that met the inclusion and exclusion criteria.

RESULTS

Psychological stressors upregulate the hypothalamic-pituitary-adrenal axis to stimulate local and systemic stress hormone production. This ultimately leads to aberrant barrier dysfunction, characterized by decreased epidermal lipid and structural protein production, decreased stratum corneum hydration and increased transepidermal water loss.

CONCLUSIONS

This evidence-based review explores the adverse effects of psychological stressors on epidermal barrier function. Future investigations using more real-life stressors are needed to elucidate further their impact on skin physiology and identify practical stress-relieving therapies that minimize and restore epidermal barrier dysfunction, particularly in at-risk populations. What's already known about this topic? The literature reports the negative effect of stress on prolonged wound healing. Less is known about the relationship between stress and epidermal barrier dysfunction, a chronic, superficial wound involving the upper epidermal layers. What does this study add? Psychological stressors impact epidermal barrier function by activating the hypothalamic-pituitary-adrenal axis to stimulate local and systemic stress hormone production. Stress hormones negatively affect the epidermal barrier by decreasing epidermal lipids and structural proteins, decreasing stratum corneum hydration and increasing transepidermal water loss. Identification of such stressors can promote stress-avoidance and stress-reduction behaviours that protect epidermal barrier function and prevent certain dermatological conditions.

Stress-induced epinephrine levels compromise murine dermal fibroblast activity through β-adrenoceptors

Stress-induced catecholamine impairs the formation of granulation tissue acting directly in fibroblast activity; however, the mechanism by which high levels of catecholamines alter the granulation tissue formation is still unclear. Thus, the aim of this study was to investigate how high levels of epinephrine compromise the activity of murine dermal fibroblasts. Dermal fibroblasts isolated from the skin of neonatal Swiss mice were preincubated with α- or β-adrenoceptor antagonists. Thereafter, cells were exposed to physiologically elevated levels of epinephrine or epinephrine plus α- or β-adrenoceptor antagonists, and fibroblast activity was evaluated. The blockade of β1- and β2-adrenoceptors reversed the increase in fibroblast proliferation, ERK 1/2 phosphorylation, myofibroblastic differentiation and the reduction of collagen deposition induced by epinephrine. In addition, the blockade of β3-adrenoceptors reversed the increase in fibroblast proliferation and nitric oxide synthesis as well as the reduction of fibroblast migration, AKT phosphorylation and active matrix metalloproteinase-2 expression induced by epinephrine. However, the blockade of α1- and α2-adrenoceptors did not alter the effects of epinephrine on the activity of murine dermal fibroblasts. In conclusion, high levels of epinephrine directly compromise the activity of neonatal mouse skin fibroblasts through the activation of β1-, β2- and β3-adrenoceptors, but not through α1- and α2-adrenoceptors.

Stress-mediated increases in systemic and local epinephrine impair skin wound healing: potential new indication for beta blockers

BACKGROUND

Stress, both acute and chronic, can impair cutaneous wound repair, which has previously been mechanistically ascribed to stress-induced elevations of cortisol. Here we aimed to examine an alternate explanation that the stress-induced hormone epinephrine directly impairs keratinocyte motility and wound re-epithelialization. Burn wounds are examined as a prototype of a high-stress, high-epinephrine, wound environment. Because keratinocytes express the beta2-adrenergic receptor (beta2AR), another study objective was to determine whether beta2AR antagonists could block epinephrine effects on healing and improve wound repair.

METHODS AND FINDINGS

Migratory rates of normal human keratinocytes exposed to physiologically relevant levels of epinephrine were measured. To determine the role of the receptor, keratinocytes derived from animals in which the beta2AR had been genetically deleted were similarly examined. The rate of healing of burn wounds generated in excised human skin in high and low epinephrine environments was measured. We utilized an in vivo burn wound model in animals with implanted pumps to deliver beta2AR active drugs to study how these alter healing in vivo. Immunocytochemistry and immunoblotting were used to examine the up-regulation of catecholamine synthetic enzymes in burned tissue, and immunoassay for epinephrine determined the levels of this catecholamine in affected tissue and in the circulation. When epinephrine levels in the culture medium are elevated to the range found in burn-stressed animals, the migratory rate of both cultured human and murine keratinocytes is impaired (reduced by 76%, 95% confidence interval [CI] 56%-95% in humans, p < 0.001, and by 36%, 95% CI 24%-49% in mice, p = 0.001), and wound re-epithelialization in explanted burned human skin is delayed (by 23%, 95% CI 10%-36%, p = 0.001), as compared to cells or tissues incubated in medium without added epinephrine. This impairment is reversed by beta2AR antagonists, is absent in murine keratinocytes that are genetically depleted of the beta2AR, and is reproduced by incubation of keratinocytes with other beta2AR-specific agonists. Activation of the beta2AR in cultured keratinocytes signals the down-regulation of the AKT pathway, accompanied by a stabilization of the actin cytoskeleton and an increase in focal adhesion formation, resulting in a nonmigratory phenotype. Burn wound injury in excised human skin also rapidly up-regulates the intra-epithelial expression of the epinephrine synthesizing enzyme phenylethanolamine-N-methyltransferase, and tissue levels of epinephrine rise dramatically (15-fold) in the burn wounded tissue (values of epinephrine expressed as pg/ug protein +/- standard error of the mean: unburned control, 0.6 +/- 0.36; immediately postburn, 9.6 +/- 1.58; 2 h postburn, 3.1 +/- 1.08; 24 h post-burn, 6.7 +/- 0.94). Finally, using an animal burn wound model (20% body surface in mice), we found that systemic treatment with betaAR antagonists results in a significant increase (44%, 95% CI 27%-61%, p < 0.00000001) in the rate of burn wound re-epithelialization.

CONCLUSIONS

This work demonstrates an alternate pathway by which stress can impair healing: by stress-induced elevation of epinephrine levels resulting in activation of the keratinocyte beta2AR and the impairment of cell motility and wound re-epithelialization. Furthermore, since the burn wound locally generates epinephrine in response to wounding, epinephrine levels are locally, as well as systemically, elevated, and wound healing is impacted by these dual mechanisms. Treatment with beta adrenergic antagonists significantly improves the rate of burn wound re-epithelialization. This work suggests that specific beta2AR antagonists may be apt, near-term translational therapeutic targets for enhancing burn wound healing, and may provide a novel, low-cost, safe approach to improving skin wound repair in the stressed individual.

Hydrocortisone Affects the Expression of Matrix Metalloproteinases (MMP-1, -2, -3, -7, and -11) and Tissue Inhibitor of Matrix Metalloproteinases (TIMP-1) in Human Gingival Fibroblasts

BACKGROUND

There is a positive correlation between the course of periodontal disease and psychosocial stress status. Stress leads to activation of the hypothalamic-pituitary-adrenal axis, resulting in increased cortisol release. The present study evaluates the effect of two different hydrocortisone concentrations on mRNA expression of matrix metalloproteinases (MMPs) and tissue inhibitor of matrix metalloproteinases (TIMPs) in cultured, human gingival fibroblasts.

METHODS

Gingival fibroblasts were stimulated with 10(-7) or 10(-9) M hydrocortisone for 24 hours; untreated cells served as controls. Alterations in the expression of MMP-1, -2, -3, -7, -11 and TIMP-1 and -2 were evaluated using real-time polymerase chain reaction and Western blotting. beta-actin mRNA expression was used as a reference to normalize gene expression.

RESULTS

Although the higher hydrocortisone concentration upregulated MMP-1, -2, -7, -11, and TIMP-1 (P <0.05) expression, the lower concentration induced downregulation or diminished upregulation. The lower hydrocortisone concentration induced a 23-fold increase in MMP-3 gene expression, whereas the higher concentration induced less upregulation; however, protein expression was regulated similarly by both hydrocortisone concentrations. The effect of hydrocortisone on TIMP-2 expression was not significant (P >0.05).

CONCLUSIONS

Hydrocortisone produced a dose-dependent regulation of MMP and TIMP expression. The higher hydrocortisone concentration significantly upregulated expression of MMP-1, -2, -7, and -11 and TIMP-1 in human gingival fibroblasts, which may constitute a mechanism underlying the increased periodontal breakdown associated with psychosocial stress status.

Restraint stress impairs early wound healing in mice via alpha-adrenergic but not beta-adrenergic receptors

Stress negatively influences wound healing in a clinically relevant manner. In an animal model, repeated restraint stress (RST) impairs wound healing in mice, partially through stress-induced glucocorticoid (GC) release. However, the role of stress-induced catecholamines (i.e., (nor)epinephrine) in healing has not been elucidated. In the present study, two 3.5mm round dermal wounds were placed on the backs of mice. Animals were restrained overnight for 3 days prior to and 5 days post-wounding. Prior to RST, mice were injected with either phentolamine or nadolol: non-specific alpha- and beta-adrenergic receptor antagonists, respectively. Pictures were taken daily to measure the rates of wound closure and contraction. Blockade of alpha-adrenergic, but not beta-adrenergic receptors, attenuated impairments in wound closure and contraction, and normalized edema, in RST mice. Thus, although stress impairment in wound healing clearly involves GCs, catecholamines play an important role via alpha-adrenergic receptor stimulation.

Thermal injury and sepsis modulates beta-adrenergic receptors and cAMP responses in monocyte-committed bone marrow cells

We have previously reported that adrenergic stimulation enhances monocytopoiesis following experimental burn injury and sepsis (BI/S). In the present work we measured beta-adrenergic receptor number and affinity in bone marrow committed monocyte progenitor cells (CD59(+)) following BI/S. We find that BI/S treatment significantly decreased monocyte progenitor cell beta-adrenergic receptors but significantly increased receptor binding affinity and isoproterenol-stimulated cAMP production. CD14 expression in macrophages derived in vitro from CD59(+) cells following BI/S was significantly increased by epinephrine and this change was blocked by beta(2)-adrenergic receptor antagonist. PCR analysis suggests the presence of beta(2)- but not beta(1)-adrenergic receptors. Enhanced adrenergic receptor signaling in CD59(+) bone marrow cells following BI/S may be important in macrophage development.

Subjective versus objective stress in noncritically ill hospitalized and outpatient adult men

A cross-sectional study of 120 subjects was performed with the purpose of evaluating stress hormones and emotional stress (anxiety) in outpatient and hospitalized subjects. The aims were to determine the degree of objective stress, as well as to correlate this finding with subjective findings, estimated using Beck's Anxiety Inventory.. METHOD: Three populations were investigated, namely outpatient clinical cases (Group I, n = 30), hospitalized clinical individuals (Group II, n = 30), and hospitalized surgical candidates (Group III, n = 30). Controls (Group IV, n = 30) were healthy volunteers who were health-care professionals and students. To avoid hormone interactions, only men were enrolled in all groups. All hospitalized subjects were tested on admission and before therapeutic interventions. Fasting epinephrine, norepinephrine, and cortisol were measured in the morning, and Beck's Anxiety Inventory was adminstered by a trained psychologist. RESULTS: The 3 patient groups displayed higher anxiety levels than the controls. Hormone concentrations did not present remarkable changes and did not correlate with subjective stress (anxiety). CONCLUSIONS: 1) Subjective disorders (as determined with Beck's Anxiety Inventory ) were a common finding in both outpatient and hospitalized populations, without differences between the various groups; 2) Objective stress (as determined by elevated hormone levels) was more difficult to confirm-findings rarely exceeded the reference range; 3) Correlation between the two variables could not be demonstrated; 4) Further studies are necessary to define stress quantification and interpretation in patient populations, especially in relationship with nutritional diagnosis and dietetic prescription.

The management of surgical wounds in a community setting

Many patients are now having minor surgical procedures carried out in the community and those patients who undergo surgery in hospital are likely to be discharged earlier due to increasing pressure on hospital beds. This article discusses the management of surgical wounds healing by both primary and secondary closure, in the community setting. Understanding the complex process of wound healing is essential if nurses are to recognize abnormalities and select appropriate treatments for patients. The stages of wound healing will be discussed in detail, including the patient's presentation. Factors that influence this process within the patient (e.g. age, nutrition, medication and pain) and those at the wound bed (e.g. exudate, tissue type and infection) will be highlighted. Choosing the correct type of surgical wound dressing for the type of wound can contribute to wound healing, patient comfort and the cost-effectiveness of treatment. Factors that need to be taken into consideration when choosing a dressing will be outlined and suggestions made for the type of dressings that would be most appropriate. The importance of accurate and detailed documentation will be highlighted as part of this process.

Altered kinetics of IL-1 alpha, IL-1 beta, and KGF-1 gene expression in early wounds of restrained mice

Inflammatory processes that occur after injury contribute to wound closure. Previous studies showed that wounds of restraint-stressed (RST) mice had a reduced number of inflammatory cells and healed more slowly compared to controls. To investigate the molecular mechanisms between stress and wound healing, we studied cutaneous gene expression of IL-1 alpha, IL-1 beta, and KGF-1. Female SKH-1 mice were restrained for 3 days before and for 5 days following placement of cutaneous wounds. Wounds were subjected to competitive RT-PCR. At day 1, RST mice had significantly lower IL-1 beta and KGF-1 mRNA than controls. At day 5, RST mice had significantly higher IL-1 alpha and IL-1 beta mRNA than controls. Treatment of RST mice with the glucocorticoid receptor antagonist RU486 restored IL-1 beta mRNA expression at day 1. Our results suggest that stress induces alterations in the kinetics of cutaneous proinflammatory cytokine and growth factor gene expression which could impair the quality of healing tissues.

Norepinephrine modulates myelopoiesis after experimental thermal injury with sepsis

OBJECTIVE

To determine whether thermal injury and sepsis cause an increase in bone marrow norepinephrine release and whether such a release influences bone marrow monocytopoiesis.

SUMMARY BACKGROUND DATA

The authors previously demonstrated enhanced bone marrow monocytopoiesis after burn with sepsis. They also showed that physiologic stress and bacterial challenge without injury could lead to a dynamic release of norepinephrine from the bone marrow compartment. In this study, they sought to determine the potential cause-and-effect relationship of bone marrow norepinephrine release on increased monocytopoiesis after burn sepsis.

METHODS

Norepinephrine release from bone marrow was determined by traditional pulse-chase methods. Tissue and bone marrow norepinephrine content was ablated by chemical sympathectomy with 6-hydroxydopamine treatment. Clonogenic potential in response to colony-stimulating factors was determined in total nucleated bone marrow cells. Dual color flow cytometry was used to document the distribution pattern of monocyte progenitors.

RESULTS

Burn sepsis induced increased norepinephrine release in bone marrow, spleen, and heart. Colony-forming assays demonstrated an increase in responsive colonies, which was significantly attenuated when norepinephrine content was reduced in animals before burn sepsis. Flow cytometric analysis of early and late monocyte progenitors showed a significantly altered distribution profile of monocyte progenitors in norepinephrine-depleted mice compared with norepinephrine-intact mice. Abrogation of bone marrow norepinephrine content resulted in a 62% survival rate in burn septic mice compared with no survivors in norepinephrine-intact mice.

CONCLUSIONS

These data suggest that enhanced bone marrow norepinephrine release after burn sepsis may play a role in bone marrow monocytopoiesis, thus contributing to the sustenance of inflammation.

Acute surgical wound care. 2: The wound healing process

The first article in this series on acute surgical wound care traced the history of surgical wound care from primitive dressings and techniques of closure used in the past to the present-day approaches. It also outlined the classification of acute surgical wounds (Vol 7(18): 1101-6). This second article describes the four stages of wound healing in acute surgical wounds, using clinical slides to illustrate the wound healing process. General factors, such as age, nutrition and medication, and local factors, including a moist environment, blood supply and wound infection, will be discussed to demonstrate their importance in promoting optimum wound healing.