Lactate down-regulates cellular poly(ADP-ribose) formation in cultured human skin fibroblasts.

BACKGROUND: Polyadenosine diphosphate-ribose (poly(ADP-ribose)) is a nuclear polymer which is derived from nicotinamide adenine dinucleotide (NAD(+)) catalysed by poly(ADP-ribose) polymerase 1 (PARP-1). Aside from the well known role of poly(ADP-ribosyl)ation (pADPR) in DNA repair, pADPR is also involved in other cellular processes such as apoptosis and gene expression. However, the factors that regulate the level of pADPR are not fully elucidated. In view of the fact that healing wounds contain high concentrations of lactate (10-15 mM) and exogenous lactate reduce the NAD(+) pool in cultured fibroblasts, we propose that high lactate lowers the level of nuclear pADPR. MATERIALS AND METHODS: Neonatal human dermal fibroblasts (NHDF) were plated to subconfluence and allowed to adhere. Cells were treated with 15 mM l-lactate and pADPR production was assessed by immunofluorescence analysis using 10H antibody. Difference in pADPR production was determined by calculation of positively stained cells compared to total cell numbers. Inhibition of PARP activity was tested by treatment with 100 microM 3-aminobenzamide (3-AB). Specificity of the lactate effect on pADPR synthesis was verified by using the analogue d-lactate. The contents of nicotinamide adenine dinucleotide (NAD(+)) and its reduced form (NADH) in lactated and non-lactated cell cultures were quantified by the enzymatic cyclic assay. RESULTS: We found that exogenous l-lactate (15 mM) can significantly depress pADPR content in cultured fibroblasts. PARP-1 activity was inhibited by 3-AB and analogue d-lactate showed no effect on pADPR synthesis. NAD(+)/NADH ratio was significantly lowered in lactated compared to non-lactated cell culture. CONCLUSIONS: Exogenous l-lactate (15 mM) can depress pADPR content in cultured fibroblasts. In view of the fact that healing wounds contain such high concentrations of lactate, we propose that down regulation of pADPR is associated with elevated tissue repair via pADPR dependent gene expression. This observation is important in understanding the stimulation of lactate-mediated protein expression during wound healing.

Wound oxygen levels during hyperbaric oxygen treatment in healing wounds.

Hyperbaric oxygen (HBO2) increases wound oxygen delivery, but few data quantify wound oxygen levels over the course of healing. We characterized these changes during and after HBO2 treatment in a rat wound model. The treatment group (n=7) received 2.0 ATA HBO2, 90 minutes BID for 15 days. Control rats (n=5) were only exposed to HBO2 during measurement. On days 5, 10, and 15, wound pO2 was measured before, during, and for an hour after HBO2 treatment. Both the peak pO2 and the pO2 one hour after HBO2 treatment were significantly greater than baseline on all days in both the treatment (p < .01) and control group (p < .05). The peak pO2 during HBO2 exposure and one hour after decreased significantly in the treatment group on day 15 compared to day 5 (p <.01, p <.05 respectively). No significant differences were found in pO2 values between days within the control group. These results demonstrate that both the peak wound oxygen levels and duration of elevation change significantly throughout the course of HBO2 treatment.

Adjuvant hyperbaric oxygen therapy (HBO2)for treatment of necrotizing fasciitis reduces mortality and amputation rate.

OBJECTIVE: A retrospective analysis of 42 patients with necrotizing soft tissue infections treated with adjunctive HBO2 to ascertain efficacy and safety. Overall mortality was 11.9% and morbidity 5%. SUMMARY BACKGROUND DATA: Necrotizing soft tissue infections have historically high rates of mortality and morbidity, including amputation. Common misconceptions that prevent widespread use of adjunctive HBO2 for this diagnosis include delays to surgery, increased morbidity, and significant complications. METHODS: Forty-two consecutive patients (average age 56.1) with necrotizing fasciitis presenting to a major referral center were treated with adjunctive HBO2 as part of an aggressive program of surgery, antibiotics, and critical care. Involved areas included the lower abdomen (15 patients), thigh and perineum (9 patients), flank (4 patients), lower leg (3 patients), and arm, shoulder, and axilla (2 patients). Co-morbidities included diabetes mellitus, chronic renal failure, intravenous drug abuse, peripheral vascular disease, and malignancy. RESULTS: Mortality was 11.9% (5 patients). Both amputations (a finger and a penis), occurred prior to transport to our facility. The average number of surgical debridements was 2.8 per patient; 1.25 performed prior to the start of HBO. The infectious process was controlled after an average of 7 HBO2 treatments were administered to ensure successful wound closure. Complications consisted of only mild ear barotrauma in 3 patients (7%), and confinement anxiety in 17 (41%) but did not prevent treatment. CONCLUSION: Compared to national reports of outcomes with "standard" regimens for necrotizing fasciitis, our experience with HBO2, adjunctive to comprehensive and aggressive management, demonstrates reduced mortality (34% v. 11.9%), and morbidity (amputations 50% v. 0%). The treatments were safe and no delays to surgery or interference with standard therapy could be attributed to HBO2.

Quantification and stratification: wound research in the future.

Advances in wound healing have been slow--from the realization of a concept through to its adoption into clinical practice. There are well-known and understood reasons for this conservative approach. One less well-tried thought is to stratify the patient's physiological status with regard to the wound. This may be the key to quantify changes in wound milieu and therefore to progress.

Insulin-like growth factor I accelerates gastric ulcer healing by stimulating cell proliferation and by inhibiting gastric acid secretion.

BACKGROUND: Given the importance of Insulin-Like Growth Factor I (IGF-I) to intestinal maintenance and the presence of IGF-I in salivary glands, we hypothesized that IGF-I participates in the healing of gastric ulcers. The aim of the study was to determine: 1) whether IGF-I applied locally would support gastric ulcer healing by increasing cell proliferation and 2) the effect of IGF-I on gastric acid secretion. METHODS: Gastric ulcers were induced with a cryoprobe. Immediately thereafter, IGF-I (0.4, 4.0 and 40 microg) or vehicle was infiltrated perifocally. In another group, animals received a daily dose of 40 micromol omeprazole subcutaneously. Ulcer healing was evaluated by ulcer size and histological examination at 7 days. Pentagastrin-stimulated gastric acid secretion was evaluated in conscious rats with gastric fistula, after IGF-I (400 microg) had been injected intravenously. RESULTS: IGF-I significantly reduced ulcer size, but only at low doses (0.4 microg/kg body weight (BW), P = 0.008; 4 microg/kg BW, P = 0.001). This effect was similar to omeprazole treatment. Histological examination after IGF-I administration showed increased cell proliferation, increased IGF-I content and down-regulated IGF-I receptors. The secretory studies demonstrated a significant decrease in gastric acid secretion 30 min after IGF-I bolus injection (IGF-I: 53 +/- 11 microEq; vehicle: 116 +/- 5 microEq; P=0.001), which lasted for more than 1 h. CONCLUSION: IGF-I stimulates gastric ulcer healing, stimulating cell proliferation and inhibiting gastric acid secretion.

Hox D3 expression in normal and impaired wound healing.

BACKGROUND: We have previously shown that Hox D3 and Hox B3 can promote angiogenesis. As angiogenesis is essential for wound healing, we examined expression of these genes in the vasculature following wounding in normal and genetically diabetic adult mice with impaired healing. METHODS: In situ hybridization was performed on tissues taken 0, 1, 4, 7, and 14 days following administration of linear wounds in wild-type and genetically diabetic mice. Expression of Hox D3 and Hox B3, angiogenesis, and synthesis of type I collagen were assessed in the wound. RESULTS: Hox B3 was expressed in endothelial cells (ECs) of both medium and small vessels in unwounded tissue, whereas little Hox D3 was detected in resting ECs. Hox D3 expression was significantly upregulated by 1 day after wounding in ECs of vessels immediately adjacent to the wound site, and expression was maintained for at least 7 days. In the diabetic mice, expression of Hox B3 was similar to that of wild-type mice. In contrast, expression of Hox D3 in ECs was significantly lower and delayed during wound repair in diabetic mice. In cultured microvascular ECs, Hox D3 selectively induced high levels of collagen I mRNA expression. Hox D3-deficient wounds of diabetic animals also displayed a reduction in expression and deposition of type I collagen. CONCLUSIONS: These results suggest that reduced angiogenesis and type I collagen in diabetic mice with impaired wound healing may be related to deficient Hox D3 expression, and restoring Hox D3 expression may enhance angiogenesis and wound repair.

Hydrogen peroxide stimulates macrophage vascular endothelial growth factor release.

Neutrophils gather at the wound site shortly after trauma and release bactericidal reactive oxygen species (ROS) and H2O2 to kill bacteria and prevent infection. Macrophages arrive at the wound in response to environmental stimuli, phagocytose foreign particles, and release vascular endothelial growth factor (VEGF), an angiogenic factor crucial for wound healing. Because oxidants are released early in inflammation and have been found to regulate transcription factors, we investigated a possible role of H2O2 in VEGF stimulation. Human U937 macrophages exposed to H2O2 and allowed to recover in H2O2-free medium rapidly showed an increase in VEGF mRNA. The H2O2-mediated mRNA increase was dose dependent, blocked by catalase, and associated with elevated VEGF in conditioned media. The increase in VEGF was also found in primary rat peritoneal macrophages and the RAW 264.7 murine macrophage cell line. Transcriptional inhibition with actinomycin D revealed no significant difference in mRNA half-life. Transient transfections with a 1.6-kb VEGF promoter-luciferase construct (Shima DT, Kuroki M, Deutsch U, Ng YS, Adamis AP, and D'Amore PA. J Biol Chem 271: 3877-3883, 1996) showed a ninefold stimulation of VEGF gene promoter activity. We concluded that H2O2 increases macrophage VEGF through an oxidant induction of VEGF promoter. This oxidant stimulation can be mediated by activated neutrophils.

A novel approach to reducing postoperative intraperitoneal adhesions through the inhibition of insulinlike growth factor I activity.

HYPOTHESIS: Interference with insulinlike growth factor I (IGF-I) activity, both systemically and intraperitoneally, reduces postoperative intraperitoneal adhesion severity. SETTING: Experimental animal model. DESIGN, INTERVENTIONS, AND MAIN OUTCOME MEASURES: Adult female rats were subjected to hypophysectomy, sham hypophysectomy (control), IGF binding protein 4 (IGFBP-4) treatment, or albumin treatment (control). All rats underwent laparotomy and uterine horn abrasion with adjacent parietal peritoneal trauma for the purpose of creating postoperative intraperitoneal adhesions. Glucocorticoids and thyroid hormone were replaced in the hypophysectomy group. On postoperative day 10, rats were weighed, subjected to phlebotomy, and killed. Postmortem laparotomies were performed and blinded observers scored uterine-peritoneal adhesions on a 0 to 3 scoring system. Plasma IGFBP-4 levels and organ weights were measured in the IGFBP-4 and albumin treatment groups. Blood samples in all rats were analyzed for IGF-I levels. RESULTS: Rats with low IGF-I levels (hypophysectomy) and inhibited IGF-I activity (IGFBP-4 treatment) formed significantly less severe adhesions than their control counterparts. As expected, rats in the hypophysectomy group displayed greater weight loss and lower plasma IGF-I levels than sham-treated rats. Rats treated with IGFBP-4 and those treated with albumin demonstrated no differences in body weight, organ weights, IGF-I levels, and IGFBP-4 levels. CONCLUSIONS: Both the reduction of systemic IGF-I levels via hypophysectomy and the inhibition of local intraperitoneal IGF-I activity via IGFBP-4 treatment resulted in diminished postoperative adhesion severity. Treatment with IGFBP-4 may play a role in postoperative adhesion prophylaxis in the future.

Adjuncts to preparing wounds for closure: hyperbaric oxygen, growth factors, skin substitutes, negative pressure wound therapy (vacuum-assisted closure).

Achieving closure in a chronic wound requires provision of adequate oxygen delivery to the tissue, adequate protein and other nutritional factors, a moist environment, an appropriate inflammatory milieu, dèbridement, and correction of contributing medical diagnoses. In some patients, these conditions are achieved easily, whereas in others, greater effort is required. Adjunctive treatments, including HBO2, growth factors, skin substitutes, and negative-pressure wound therapy (e.g., V.A.C.) can provide the proper conditions for healing in appropriately selected patients.

Tissue oxygenation, perfusion, and position in patients with venous leg ulcers.

OBJECTIVES: The purpose of this study was to compare the partial pressure of transcutaneous tissue oxygen (TcPO2) in persons with venous ulcers in four positions with and without inspired oxygen. METHODS: TcPO2 was evaluated two times, 4 weeks apart at a chest reference and three lower extremity sites. RESULTS: Lower extremity resting TcPO2 levels were lower in patients with venous ulcers than in healthy adults. Minimal changes in TcPO2 occurred with position changes when subjects breathed room air. When arterial oxygen saturation was increased using inspired oxygen, TcPO2, used as an indicator of perfusion, was lower during leg elevation, sitting, and standing compared to lying supine (p < 0.05). CONCLUSIONS: Control of peripheral circulation and tissue oxygenation may be impaired in persons with venous ulcers. Leg elevation, sitting, and standing decreased wound perfusion and may not be beneficial to individuals with venous insufficiency and ulceration. Research is needed to explore relationships among tissue oxygenation, blood perfusion, compression, positioning, and venous ulcer healing.

Lactate elicits vascular endothelial growth factor from macrophages: a possible alternative to hypoxia.

Macrophages respond to various stimuli to produce angiogenic factors but few mechanistic details are known. We examined the effects of hypoxia, lactate and nicotinamide on the expression of vascular endothelial growth factor by cultured macrophages. These agents were chosen because they down-regulate polyadenosine diphosphoribose levels. Following exposure, conditioned media were analyzed for vascular endothelial growth factor protein. Nicotinamide adenine dinucleotide, polyadenosine diphosphoribose, and vascular endothelial growth factor mRNA were measured in the cellular fraction. Angiogenic capacity of the conditioned media was tested in rabbit corneas and Matrigel implants. All three agents, hypoxia, lactate and nicotinamide, elicited significantly increased levels of vascular endothelial growth factor mRNA and vascular endothelial growth factor in the conditioned media, and these levels were paralleled by their angiogenic activity. Polyadenosine diphosphoribose in the cellular fraction was correspondingly depressed. Anti-vascular endothelial growth factor antibody inhibited most of the angiogenic response whereas anti-basic fibroblast growth factor antibody had little effect. We propose that redox changes associated with the alteration of cellular nicotinamide adenine dinucleotide and polyadenosine diphosphoribose are involved in lactate-mediated VEGF expression.

Subcutaneous perfusion and oxygen during acute severe isovolemic hemodilution in healthy volunteers.

HYPOTHESIS: Acute severe isovolemic anemia (to a hemoglobin [Hb] concentration of 50 g/L) does not decrease subcutaneous wound tissue oxygen tension (PsqO(2)). SETTING: University hospital operating room and inpatient general clinical research center ward. SUBJECTS: Twenty-five healthy, paid volunteers. METHODS: Subcutaneous oxygen tension and subcutaneous temperature (Tsq) were measured continuously during isovolemic hemodilution to an Hb level of 50 g/L. In 14 volunteers (initially well-perfused), "normal" perfusion (Tsq >34.4 degrees C) was achieved by hydration and systemic warming prior to starting isovolemic hemodilution, while in 11 volunteers (perfusion not controlled [PNC]), no attempt was made to control perfusion prior to hemodilution. MAIN OUTCOME MEASURES: Measurements of PsqO(2), Tsq, and relative subcutaneous blood flow (flow index). RESULTS: While PsqO(2), Tsq, and flow index were significantly lower in PNC vs well-perfused subjects at baseline, there was no significant difference between them at the Hb of 50 g/L (nadir). Subcutaneous PO(2) did not decrease significantly in either group. Arterial PO(2) was not different between the groups, and did not change significantly over time; Tsq and flow index increased significantly from baseline to nadir Hb in both groups. CONCLUSIONS: The level of PsqO(2) was maintained at baseline levels during hemodilution to Hb 50 g/L in healthy volunteers, whether they were initially well-perfused or mildly underperfused peripherally. Given the significant increase in Tsq and flow index, this resulted from a compensatory increase in subcutaneous blood flow sufficient to maintain oxygen delivery. Wound healing depends to a large extent on tissue oxygen delivery, and these data suggest that even severe anemia by itself would not be sufficient to impair wound healing. Thus, transfusion of autologous packed red blood cells solely to improve healing in surgical patients with no other indication for transfusion is not supported by these results.

Effects of steroids and retinoids on wound healing.

HYPOTHESIS: Anti-inflammatory corticosteroids significantly impair wound healing. Retinoids partially, but significantly, reverse this effect. Little is known about the mechanism of steroid retardation or retinoid reversal. We hypothesized that corticosteroids lower transforming growth factor-beta (TGF-beta) and insulin-like growth factor-I (IGF-I) levels and tissue deposition in wounds and that retinoids stimulate corticosteroid-impaired TGF-beta and IGF-I release and collagen production. DESIGN: Randomized controlled trial. SETTING: Wound healing research laboratory. PARTICIPANTS: Animal study. INTERVENTIONS: Four wire mesh wound cylinders were implanted subcutaneously into the backs of 72 male Sprague-Dawley rats. Wound healing was impaired by a single subcutaneous injection of 6 mg of methylprednisolone acetate (Depo-Medrol). Two preparations of retinoids were used in separate experiments: all-trans-retinoic acid and 9-cis-retinoic acid that were fed orally. MAIN OUTCOME MEASURES: Hydroxyproline content was measured in the healing tissue and TGF-beta and IGF-I levels were analyzed in the wound fluid. RESULTS: Methylprednisolone treatment significantly decreased TGF-beta and IGF-I levels in the wound fluid and hydroxyproline content in the tissue (P<.05). Oral all-trans- and 9-cis-retinoic acid partially reversed the TGF-beta and IGF-I decrease and significantly increased hydroxyproline content toward normal levels (P<.05). Oral all-trans-retinoic acid enhanced collagen deposition, TGF-beta and IGF-I levels over normal chow fed control animals (P<.05). CONCLUSIONS: Steroids and retinoids have antagonistic effects on growth factors and collagen deposition in wound healing. These effects can be relevant for treatment options in a clinical setting.

Effect of hyperoxia on vascular endothelial growth factor levels in a wound model.

HYPOTHESIS: Hyperbaric oxygen (HBO) therapy increases vascular endothelial growth factor (VEGF) levels in wounds. DESIGN: Wounds were monitored for oxygen delivery during HBO treatment, and wound fluids were analyzed for VEGF and lactate on days 2, 5, and 10 following wounding. SETTING: Experimental animal model. INTERVENTIONS: Rats were randomized to HBO therapy and control groups. The HBO therapy was administered for 90 minutes, twice daily with 100% oxygen at 2.1 atmospheres absolute. Treatment was administered for 7 days following wounding. MAIN OUTCOME MEASURES: Vascular endothelial growth factor, PO(2), and lactate levels in wound fluid were measured on days 2, 5, and 10. RESULTS: Wound oxygen rises with HBO from nearly 0 mm Hg to as high as 600 mm Hg. The peak level occurs at the end of the 90-minute treatment, and hyperoxia of lessening degree persists for approximately 1 hour. The VEGF levels significantly increase with HBO by approximately 40% 5 days following wounding and decrease to control levels 3 days after exposures are stopped. Wound lactate levels remain unchanged with HBO treatment (range, 2.0-10.5 mmol/L). CONCLUSIONS: Increased VEGF production seems to explain in part the angiogenic action of HBO. This supports other data that hypoxia is not necessarily a requirement for wound VEGF production.

Physiology of wound healing.

Wound healing is a complicated process that recruits at least 4 distinct cell types. Though the process is continuous, it is commonly referred to as occurring in "phases." The main phases of wound healing include coagulation, which begins immediately after injury; inflammation, which initiates shortly thereafter; a migratory and proliferative process, which begins within days and includes the major processes of healing; and a remodeling process, which may last for up to a year and is responsible for scar tissue formation and development of new skin. Wound healing is affected by several factors. These include local factors (growth factors, edema and ischemia, low oxygen tension, and infection), regional factors (arterial insufficiency, venous insufficiency, and neuropathy), systemic factors (inadequate perfusion and metabolic disease), and other miscellaneous factors, such as nutritional state, preexisting illnesses, exposure to radiation therapy, and smoking. In general, chronic wounds may be managed by preventing or medically treating infections through debridement and occlusive dressings. For wounds that are unresponsive to such interventions, the use of skin replacements is becoming a viable option. In this regard, a product such as Graftskin (APLIGRAF, Organogenesis Inc, Canton, MA, and Novartis Pharmaceuticals Corporation, East Hanover, NJ), a bilayered living skin construct with allogeneic dermis and epidermis, is a positive development.

Relaxin induces vascular endothelial growth factor expression and angiogenesis selectively at wound sites.

Relaxin is a reproductive hormone that has historically been characterized as being responsible for pubic ligament loosening and cervical ripening. Recently, relaxin has been associated with neovascularization of the endometrial lining of the uterus, potentially via specific induction of vascular endothelial growth factor. Previously conducted clinical studies using partially purified porcine relaxin have described relaxin's ability to stimulate the healing of ischemic wounds, suggesting that relaxin may also have angiogenic effects at sites of ischemic wound healing. In the present study, relaxin's angiogenic effects in the context of wound repair were tested in rodent models of angiogenesis and wound healing. Relaxin showed an ability to stimulate new blood vessel formation, particularly at ischemic wound sites, and to induce both vascular endothelial growth factor and basic fibroblast growth factor specifically in cells, presumably including macrophages, collected from wound sites. Resident macrophages collected from nonwound sites, such as the lung, did not show altered expression of these cytokines following relaxin administration. Because angiogenic wound cells are frequently macrophages, THP-1 cells, a cell line of monocyte lineage that binds relaxin specifically, were tested for and shown to induce vascular endothelial growth factor and basic fibroblast growth factor in response to relaxin. In conclusion, relaxin may be useful in the treatment of ischemic wounds by stimulating angiogenesis via the induction of vascular endothelial growth factor and basic fibroblast growth factor in wound macrophages.

Impaired wound contraction in stromelysin-1-deficient mice.

OBJECTIVE: To determine whether the deletion of stromelysin-1, a single metalloproteinase gene product, will alter the time course and quality of dermal wound repair in mice. SUMMARY BACKGROUND DATA: After dermal injury, a highly coordinated program of events is initiated by formation of a fibrin clot, followed by migration of keratinocytes, contraction of the dermis, recruitment of inflammatory macrophages, formation of granulation tissue with angiogenesis, and finally tissue remodeling. Matrix metalloproteinases are rapidly induced in the dermis and granulation tissue and at the leading edge of the epidermis in the healing wounds. METHODS: Incisional and circular full-thickness wounds 2 to 10 mm were made in the dermis of stromelysin-1-deficient and wild-type mice. The wounds were analyzed for rate of cellular migration and epithelialization. The wound contraction was examined by immunohistochemical staining for alpha-smooth muscle actin and fluorescent staining for fibrillar actin. RESULTS: Independent of the age of the animal, excisional wounds in stromelysin-1-deficient mice failed to contract and healed more slowly than those in wild-type mice. Cellular migration and epithelialization were unaffected in the stromelysin-1-deficient animals. The functional defect in these mice is failure of contraction during the first phase of healing because of inadequate organization of actin-rich stromal fibroblasts. CONCLUSIONS: Excisional dermal wound healing is impaired in mice with a targeted deletion in the stromelysin-1 gene. Incisional wound healing is not affected. These data implicate stromelysin-1 proteolysis during early wound contraction and indicate that stromelysin-1 is crucial for the organization of a multicellular actin network.

Laparoscopic vs open adrenalectomy for the treatment of primary hyperaldosteronism.

HYPOTHESIS: That the clinical presentations, biochemical profiles, and surgical outcomes of patients treated with laparoscopic vs open adrenalectomy for primary hyperaldosteronism are different. DESIGN, SETTINGS, PATIENTS, AND INTERVENTIONS: The medical records of 80 patients with primary hyperaldosteronism who underwent open adrenalectomy between 1975 and 1986 or laparoscopic adrenalectomy between 1993 and 1998 at the University of California-San Francisco were reviewed by a single unblinded researcher (W.T.S.). MAIN OUTCOME MEASURES: Severity of hypertension and hypokalemia at diagnosis, their improvement after adrenalectomy, and operative complications. RESULTS: Thirty-eight patients underwent open adrenalectomy and 42 patients underwent laparoscopic adrenalectomy. The patients who underwent open adrenalectomy had documented hypertension for a median of 5 years before surgery; all had diastolic blood pressures greater than 100 mm Hg. Laparoscopically treated patients had documented hypertension for a median of 2.5 years preoperatively, and 20 (48%) had diastolic blood pressures greater than 100 mm Hg. The median preoperative serum potassium levels for the open and laparoscopic groups were 2.6 mmol/L and 3.3 mmol/L, respectively; the mean serum aldosterone levels were 1.47 nmol/L and 1.30 nmol/L. Thirty-two (84%) of the 38 patients who underwent open surgery and 41 (98%) of the 42 patients treated laparoscopically had adrenal adenomas. The sensitivity of preoperative computed tomographic scanning for adenomas was 83% for the patients treated with open adrenalectomy and 93% for those treated laparoscopically. There were 4 postoperative complications in the open surgery group and none in the laparoscopic group. Postoperatively, 30(81%) of 37 patients (excluding 1 patient who died of adrenocortical carcinoma) in the open surgery group and 37 (88%) of 42 patients treated laparoscopically were normotensive. Post-operative values were 3.6 to 5.0 of serum potassium per liter and 3.5 to 4.9 of serum potassium per liter in the open and laparoscopic groups, respectively. CONCLUSIONS: Patients who are treated with laparoscopic adrenalectomy for primary hyperaldosteronism are being referred with less severe hypertension and hypokalemia than patients formerly treated with open adrenalectomy. Patients treated laparoscopically had fewer postoperative complications and were equally likely to improve in blood pressure and hypokalemia. Laparoscopic adrenalectomy has become the treatment of choice for patients with primary hyperaldosteronism because of lower morbidity.