Effect of delayed administration of corticosteroids on wound contraction

Cell sheet technology-driven re-epithelialization and neovascularization of skin wounds

Skin regeneration remains a challenge, requiring a well-orchestrated interplay of cell-cell and cell-matrix signalling. Cell sheet (CS) engineering, which has the major advantage of allowing the retrieval of the intact cell layers along with their naturally organized extracellular matrix (ECM), has been poorly explored for the purpose of creating skin substitutes and skin regeneration. This work proposes the use of CS technology to engineer cellular constructs based on human keratinocytes (hKC), key players in wound re-epithelialization, dermal fibroblasts (hDFb), responsible for ECM remodelling, and dermal microvascular endothelial cells (hDMEC), part of the dermal vascular network and modulators of angiogenesis. Homotypic and heterotypic three-dimensional (3-D) CS-based constructs were developed simultaneously to target wound re-vascularization and re-epithelialization. After implantation of the constructs in murine full-thickness wounds, human cells were engrafted into the host wound bed and were present in the neotissue formed up to 14 days post-implantation. Different outcomes were obtained by varying the composition and organization of the 3-D constructs. Both hKC and hDMEC significantly contributed to re-epithelialization by promoting rapid wound closure and early epithelial coverage. Moreover, a significant increase in the density of vessels at day 7 and the incorporation of hDMEC in the neoformed vasculature confirmed its role over neotissue vacularization. As a whole, the obtained results confirmed that the proposed 3-D CS-based constructs provided the necessary cell machinery, when in a specific microenvironment, guiding both re-vascularization and re-epithelialization. Although dependent on the nature of the constructs, the results obtained sustain the hypothesis that different CS-based constructs lead to improved skin healing.

Topical tacrolimus does not negatively impact acute skin wound healing

Despite the increasing use of topical tacrolimus, there is little information about its effect on skin wound healing. To determine effects on acute cutaneous wound healing, two full-thickness skin wounds were imparted on the backs of 45 hairless mice, which were then divided into vehicle-, topical tacrolimus- and topical steroid-treated group. Each drug was topically applied once daily. The wound area was assessed by using dermoscopic images every two days after wounding. At 3, 7 and 11 days after wounding, 10 wounds in each group were collected for semi-quantitative analysis of histological features including re-epithelialization, polymorphonuclear leucocytes, fibroblasts and collagen. We also checked the mRNA expression levels of EGF, TGF-β, TNF-α and IL-1α. While topical application of clobetasol propionate was found to delay re-epithelialization and infiltration of polymorphonuclear leucocyte, topical treatment with tacrolimus showed patterns similar to that of the vehicle. In the tacrolimus-treated group, mRNA expression levels of IL-1α and TGF-β were slightly decreased, while the others were similar with the vehicle-treated group. Unlike steroid, topical tacrolimus, therefore, did not disturb the wound healing process in a murine skin wound model.

Use of an in vitro model of tissue-engineered skin to investigate the mechanism of skin graft contraction

Skin graft contraction leading to loss of joint mobility and cosmetic deformity remains a major clinical problem. In this study we used a tissue-engineered model of human skin, based on sterilized human adult dermis seeded with keratinocytes and fibroblasts, which contracts by up to 60% over 28 days in vitro, as a model to investigate the mechanism of skin contraction. Pharmacologic agents modifying collagen synthesis, degradation, and cross-linking were examined for their effect on contraction. Collagen synthesis and degradation were determined using immunoassay techniques. The results show that skin contraction was not dependent on inhibition of collagen synthesis or stimulation of collagen degradation, but was related to collagen remodelling. Thus, reducing dermal pliability with glutaraldehyde inhibited the ability of cells to contract the dermis. So did inhibition of matrix metalloproteinases and inhibition of lysyl oxidase-mediated collagen cross-linking, but not transglutaminase-mediated cross-linking. In summary, this in vitro model of human skin has allowed us to identify specific cross-linking pathways as possible pharmacologic targets for prevention of graft contracture in vivo.

Laparoscopic adrenalectomy for functioning and non-functioning adrenal tumors: analysis of surgical aspects based on histological types

BACKGROUND

The aim of this study was to evaluate whether hormonal functions of the tumor influence the operative results of laparoscopic adrenalectomy, and to analyse the clinical outcomes in patients with various hormonally active adrenal tumors.

METHODS

Clinical and pathological records of 68 patients were reviewed. The average age of patients was 40 years (range 20-75); 39 were women and 29 men. For the comparison, patients were divided into the non-functioning tumor group (n = 22) and the functioning tumor group (n = 46).

RESULTS

All laparoscopic adrenalectomies were finished successfully, and no open surgery was necessary. The median operative time and blood loss in the two groups were similar; however, in subgroup analysis, operative time for pheochromocytoma was significantly longer than that for non-functioning tumor (P = 0.044). No difference was noted in intra- and postoperative data between the groups. Of the 22 patients with aldosteronoma, 18 (81.8%) became normotensive and no longer required postoperative blood pressure medications. Adrenalectomy led to an overall reduction in the median number of antihypertensive medications (P < 0.001). All patients with Cushing adenoma had resolution or improvement of the signs and symptoms during follow-up periods. There was no evidence of biochemical or clinical recurrence in any patient with pheochromocytoma.

CONCLUSION

The results of this retrospective review document that laparoscopic adrenalectomy is a safe and effective treatment for functioning as well as non-functioning adrenal tumors, although endocrinologic features may play a significant role.

Chronic wounds

Chronic wounds are a challenge to treat for the clinician. We present a current overview of intrinsic and extrinsic factors in the development chronic nonhealing wounds. Solutions to some of these difficult problems are presented.

Mechanics of wound healing and importance of Vacuum Assisted Closure in urology

PURPOSE

We discuss the mechanisms of wound healing and our experience with the Vacuum Assisted Closure device (Kinetic Concepts, Inc., San Antonio, Texas) for complex urogenital wounds.

MATERIALS AND METHODS

The literature obtained from a Medline search on wound healing, wound failure and vacuum assisted closure was reviewed. In addition, we reviewed our experience with negative pressure wound therapy.

RESULTS

Wound healing is a complex interaction between the reticuloendothelial and immune systems, in addition to correctable internal and external factors. Understanding the healing process improves outcomes and decreases patient morbidity. Negative pressure wound therapy has hastened wound healing and it adds significant improvement in the arsenal of choices available.

CONCLUSIONS

Vacuum Assisted Closure is a therapeutic alternative that complements surgical and medical intervention in patients with complex wounds.

Bilateral adrenalectomy for Cushing's syndrome: a comparison between laparoscopy and open surgery

We report our experience with bilateral adrenalectomy for treatment of Cushing's syndrome and we compare the outcome of laparoscopy with open surgery in terms of effectiveness and safety. A series of 23 patients underwent bilateral adrenalectomy for treatment of Cushing's syndrome [Cushing's disease in 16, ectopic ACTH syndrome in 2, and ACTH-independent macronodular adrenal hyperplasia (AIMAH) in 5 cases]. From 1993 to 1996, all patients were treated using an open approach (Group A), while from 1997 all patients were treated using a transperitoneal laparoscopic approach (Group B). The comparison between the 2 groups was performed considering patients characteristics, operative times, blood losses, intraoperative and post-operative complications, analgesic consumption, post-operative hospital stay and recovery. Open surgery was performed in 10 patients and laparoscopy in 13 patients. No significant difference was recorded between the two groups as to patients' characteristics and complications. Mean operative time was significantly increased in Group B, while post-operative hospital stay was significantly longer in Group A. Laparoscopic bilateral adrenalectomy can be safely and effectively employed to treat Cushing's syndrome. However, long operatives times may represent a limitation especially in high risk patients.

The effects of dexamethasone on bone fusion in an experimental model of posterolateral lumbar spinal arthrodesis

OBJECT

The use of corticosteroid agents during the healing phase after spinal arthrodesis remains controversial. Although anecdotal opinion suggests that corticosteroids may inhibit bone fusion, such an effect has not been substantiated in clinical trials or laboratory investigations. This study was undertaken to delineate the effect of exogenous corticosteroid administration on bone graft incorporation in an experimental model of posterolateral lumbar fusion.

METHODS

An established, well-validated model of lumbar intertransverse process spinal fusion in the rabbit was used. Twenty-four adult New Zealand white rabbits underwent L5-6 bilateral posterolateral spinal fusion in which autogenous iliac crest bone graft was used. After surgery, the animals were randomized into two treatment groups: a control group (12 rabbits) that received intramuscular injections of normal saline twice daily and a dexamethasone group (12 rabbits) that received intramuscular dexamethasone (0.05 mg/kg) twice daily. After 42 days, the animals were killed and the integrity of the spinal fusions was assessed by radiography, manual palpation, and biomechanical testing. In seven (58%) of the 12 control rabbits, solid posterolateral fusion was achieved. In no dexamethasone-treated rabbits was successful fusion achieved (p = 0.003). Tensile strength and stiffness of excised spinal segments were significantly lower in dexamethasone-treated animals than in control animals (tensile strength 91.4+/-30.6 N and 145.3+/-48.2, respectively, p = 0.004; stiffness 31.4+/-11.6 and 45.0+/-15.2 N/mm, respectively, p = 0.02).

CONCLUSIONS

The corticosteroid agent dexamethasone inhibited bone graft incorporation in a rabbit model of single-level posterolateral lumbar spinal fusion, inducing a significantly higher rate of nonunion, compared with that in saline-treated control animals.

Laparoscopic versus open adrenalectomy in Cushing's syndrome and disease

BACKGROUND

Adrenalectomy in Cushing's syndrome and disease involves particular risks and complications. The aim of the study was to compare the open posterior and the flank laparoscopic approaches in this group of patients.

METHODS

Forty patients who underwent unilateral or bilateral adrenalectomy for hypercortisolism between 1991 and 1999 were studied. Patients were divided as follows: adenoma--5 laparoscopic and 6 open; hyperplasia--17 laparoscopic and 12 open. Demographics, surgical details, outcome, and complications were comparatively analyzed.

RESULTS

Patients undergoing laparoscopic or open adrenalectomy were comparable in terms of age, sex distribution, body mass index, respiratory status, and anesthetic risk. Operative time was longer in the laparoscopic group. One patient in the laparoscopic group died of upper gastrointestinal tract bleeding on postoperative day 17. Two patients in the open group and one in the laparoscopic group experienced postoperative complications. Cure of the disease occurred in all patients. Mild abdominal wall pain developed in one patient in each group. No abdominal wall weakness was identified in either group.

CONCLUSIONS

Cure rate and operative and long-term morbidity were similar for laparoscopic and open adrenalectomies in this series. However, it is important to emphasize that late complications in our patients who underwent the posterior open procedure were rather infrequent.

Impediments to wound healing

Chronic wounds will often heal in a short period of time if factors that inhibit wound healing are identified and managed. Recombinant growth factor therapy may provide an added stimulus to healing in certain types of chronic wounds. However, there remains no substitute for a physiologic environment conducive to tissue repair and regeneration, without which the efficacy of growth factor therapy is questionable. Some of the most commonly encountered and clinically significant impediments to wound healing include wound hypoxia, infection, presence of debris and necrotic tissue, use of anti-inflammatory medications, a diet deficient in vitamins or minerals, or general nutritional deficiencies, tumors, environmental factors, and metabolic disorders, such as diabetes mellitus. Treatment of chronic wounds should be directed against the main etiologic factors responsible for the wound. Moreover, factors that may impede healing must be identified and, if possible, corrected, for healing to occur.

Tissue repair of the epidermis and dermis

Wounds of the skin heal in a predictable fashion and at a fairly constant rate if impediments to healing can be avoided. For the skin wound of the hand, the therapist and surgeon face paradoxic demands to balance optimal immobilization for wound healing with optimal motion for function. As long as the wound remains stable, therapy can begin very early in the postoperative period without interruption of the wound-healing process.

Adrenal surgery for hypercortisolism--surgical aspects

BACKGROUND

Patients with endogenous hypercortisolism are thought to be at high risk for adrenalectomy and may experience significant postoperative surgical mortality/morbidity.

METHODS

From 1981 through 1991, 91 patients underwent adrenal resection for endogenous hypercortisolism. Causes were adrenal-dependent Cushing's syndrome (50%), pituitary-dependent Cushing's syndrome (27%), and an ectopic adrenocorticotropic hormone-secreting tumor (23%). Causes of adrenal-dependent Cushing's syndrome were adrenocortical adenoma (72%), bilateral nodular hyperplasia (20%), and adrenocortical carcinoma (8%). Comparative mean length of hospitalization for patients undergoing unilateral anterior versus posterior approach was 8 versus 6 days, and bilateral anterior versus posterior was 11 versus 6 days.

RESULTS

Operative mortality was 2.6%. Only one patient had a wound infection, and no patient had either a venous thrombosis or a pulmonary embolism. Delayed wound healing occurred in three patients.

CONCLUSIONS

(1) Adrenal surgery can be performed today with low morbidity/mortality. (2) Although there is an effect of hypercortisolism on wound healing, infection, diabetes, hypertension, coronary artery disease, and pulmonary embolism, it was possible to perform adrenalectomy surgically with acceptable morbidity and mortality. (3) These results may serve as a standard against which laparoscopic adrenalectomy may be compared.

A prospective investigation of the healing of grafted pretibial wounds with early and late mobilisation

The aims of this study were to determine whether early mobilisation delays wound healing after meshed split skin graft repair of pretibial wounds and to identify other factors delaying the healing of these wounds. A prospective randomised controlled trial was conducted to compare the time to complete healing of patients mobilised early (the first postoperative day) against those who mobilised late (the tenth postoperative day). There was no difference in time to complete healing. Patients with a history of oral steroid therapy had a mean delay in wound healing of approximately 8 days (p < 0.02). The severity of tissue damage, as indicated by undermining of the skin margins, damage to the fascia and exposure of the periosteum, correlated with delayed wound healing (p < 0.05).

Biology of wound healing

A clear understanding of wound healing is vital to a rational surgical approach. This article describes the major biologic processes of tissue repair and the factors influencing the healing processes, and it discusses specific wound-healing problems and recommends management regimens.

Capsular contracture and steroid-related complications in augmentation mammoplasty

An analysis of the data obtained in 91 of 161 patients (57%) who had undergone augmentation mammoplasty between 1973 and 1978 demonstrates that corticosteroids should be used with caution and that more data are needed before their efficacy is assured. Moreover, the authors believe that a better understanding of the breast contracture mechanism and specific pharmacologic agents is necessary in order to control the process of capsular contracture.

Serum zinc and urinary zinc excretion after renal allotransplantation

In nine kidney-transplanted patients, receiving prednisone as part of the immunosuppression, serum zinc and urinary zinc excretion were measured for a period of 5-7 weeks after the transplantation. Serum zinc decreased significantly from normal pretransplant values to subnormal vaues 1-5 days after the transplantation. Thereafter, the serum zinc rose again, and after 2-3 weeks, before start of reduction of prednisone, the serum zinc had risen to a level that was not significantly lower than the pretransplant level. Urinary zinc excretion was generally elevated, especially just after the transplantation. In patients with initially good kidney function function the zinc clearance to creatinine clearance ratio was significantly higher during the first week after the transplantation than in the rest of the observation period. Similar findings have been reported after major surgery, and no correlation between serum zinc and the corticosteroid dose was demonstrable. Therefore, in renal allotransplantation, no special supplementation of zinc seems necessary beyond what may be justified by the effect of the surgical trauma.

Effects of cortisone acetate, methylprednisolone and medroxyprogesterone on wound contracture and epithelization in rabbits

Standardized flank wounds were made on 20 rabbits divided into the following five groups: Group 1 served as controls, Group 2 were given cortisone acetate 6.25 mg/kg/day (I.M.), Group 3--methylprednisolone (Solu-Medrol) 1 mg/kg/day, Group 4--medroxyprogesterone (Depo-Provera) 35 mg/kg/day, Group 5--methylprednisolone 1 mg/kg/day and medroxyprogresterone 35 mg/kg/day. Wound contracture and epithelization was measured by planimetry of photographs taken twice weekly; weekly weights were recorded, and the maturation phase of wound healing followed in the control and methylprednisolone groups. All three steroids prolonged the latent phase of wound healing, slowed the rate and decreased the total amount of contracture. Cortisone showed the most inhibition of wound contracture and was the only steroid to inhibit epithelization suggesting it may have a slightly different or more potent mode of action. When the methylprednisolone group was followed for seven weeks on daily injections, the maturation phase of wound healing was inhibited, and this inhibition persisted during the next nine weeks after the drug was withdrawn. Only the control and the medroxyprogesterone group gained weight. Combining medroxyprogesterona and methylprednisolone resulted in the severest weight loss of 20% with a 60% mortality.