Evaluation of clinical and laboratory correlates of sickle leg ulcers

The exact mechanism for the occurrence of sickle leg ulcers (SLUs) has not been fully explained, although, popular opinion supports a multifactorial etio‐pathogenetic process. Leg ulceration in sickle cell is a chronic and debilitating condition which is difficult to treat and may worsen the psychosocial impact of this illness. This study aims to evaluate the laboratory and clinical correlates of SLUs. One hundred sixty‐seven patients who had been diagnosed with sickle cell anemia (homozygous S) had their steady‐state hemoglobin concentration (Hb), hematocrit, white cell count, platelet count, serum bilirubin, and aspartate transaminase (AST) as well as frequency of crisis per annum evaluated with respect to their relationship to the occurrence of leg ulcers. They were aged 6–53 years (mean age 24.3 years), and prevalence of leg ulcer was found to be 2.75 per 1000 (2.54 per 1000 in females and 2.83 per 1000 in males). The independent sample t‐test showed a significant difference in the serum AST levels in those with SLU (p = 0.029), though a positive correlation did not exist. Other predictors of disease severity found to have positive relationship with each other were the AST and total serum bilirubin 0.207 (p = 0.012); Hb and age 0.130 (p = 0.035); Hb and white cell count ?0.159 (p = 0.010), white cell count and age ?0.113 (p = 0.018). SLUs do not occur in patients with severe disease in sickle cell. The clinical and laboratory indicators of severe sickle cell disease do not correlate positively with the occurrence of SLU. Serum AST may have a relationship with leg ulceration in these patients. Environmental factors most likely play a major part in the etiopathogenesis of leg ulcer and this may require further studies in different sociocultural settings.     

Localization of platelet-derived growth factor receptor subunit expression in chronic venous leg ulcers

Cellular responses to platelet-derived growth factor, which affects all phases of the wound healing process, are dependent on the interaction of the growth factor with its cell surface receptors. Recently, we have shown that the platelet-derived growth factor-receptor was not expressed in uninjured human skin. In acute human wounds healing by secondary intention, both platelet-derived growth factor-receptor subunits were coordinately expressed, whereas no expression was found after reepithelialization at day 47. Even though impaired wound healing may be due to uncoordinated expression or the failure to express platelet-derived growth factor-receptor subunits, little is known regarding their expression in chronic ulcers. We studied the localization of platelet-derived growth factor-receptor expression in chronic venous leg ulcers of 15 patients with a median age of 73 years. Cryostat sections of biopsy specimens were immunostained with the use of antibodies against the alpha- and the beta-platelet-derived growth factor subunits. RNA was extracted from biopsy specimens and subjected to Northern blot analysis with the use of oligolabeled complementary DNA for the platelet-derived growth factor-receptor. Platelet-derived growth factor-receptor alpha- and beta-subunit expression was found in fibroblast-like cells within the wound bed and in cells beneath the epidermis of the wound edge. Platelet-derived growth factor-receptor beta-subunit expression was detected in endothelial cells of the vessels, in the granulation tissue, and the wound edge, whereas platelet-derived growth factor-receptor alpha-subunit was not expressed in endothelial cells of the uninjured skin. This finding suggests that the platelet-derived growth factor alpha-subunit may be involved in vessel formation during tissue repair. Both platelet-derived growth factor-receptor subunits were expressed at the messenger RNA level indicating that the synthesis is at least partly regulated at a pretranslational level. As the cellular responsiveness to growth factors depends on their specific receptors, our finding that both platelet-derived growth factor-receptor subunits are expressed in chronic venous ulcers substantiates the concept of therapeutic trials with recombinant platelet-derived growth factor.     

An overview of the relationship between anaemia,iron, and venous leg ulcers

The factors preventing healing in venous leg ulcers are still not fully understood. Iron‐mediated tissue damage has been hypothesised, yet anecdotally anaemia is also thought to have a negative effect on wound healing. This article summarises the current evidence for these theories and their likely effects in the context of venous ulceration. A comprehensive search of the literature was conducted. Studies suggest that a number of forms of iron including haemosiderin and ferritin are implicated in progression of venous disease, ulcer formation, and impaired healing, which is thought to be primarily free radical mediated. There is a paucity of evidence for the role of iron deficiency and anaemia on ulcer healing; however, there is likely to be a highly complex interplay between the damaging effects of iron on local tissues and the negative effects of anaemia‐mediated tissue hypoxia. Studies looking at options to increase local oxygen delivery such as topical haemoglobin suggest that this may have an impact on some aspects of healing, but findings are generally inconclusive. There is growing evidence that locally elevated iron levels may have a detrimental effect on ulcer healing and formation; however, more robust research is needed.     

A treatment algorithm to identify therapeutic approaches for leg ulcers in patients with sickle cell disease

Sickle cell leg ulcers (SCLUs) are a common complication of sickle cell disease (SCD). Patients who develop ulcers appear to have a more severe haemolysis‐associated vasculopathy than individuals who do not develop them, and manifest other complications such as priapism and pulmonary hypertension. SCLUs are slow to heal and often recur, affecting both the emotional and physical well‐being of patients. Here we summarise what is known about the pathophysiology of SCLUs, describe available treatment options and propose a treatment algorithm.     

Prognostic role of factor XIII gene variants in nonhealing venous leg ulcers

OBJECTIVE: Many factors impair healing of chronic venous ulcer (CVU), and many theories have been proposed to explain their pathogenesis. Coagulation factor XIII (FXIII) influences tissue regeneration and angiogenesis with effects on wound healing. Because FXIII properties depend upon its genetic variants, we investigated whether intragene polymorphisms may have modulating effects on the CVU area. METHODS: The study included 121 patients with nonhealing CVUs (CEAP clinical class C6) that included 67% with primary chronic venous disease (CVD), 26% with post-thrombotic ulcers, and 7% with mixed ulcer origin. Polymerase chain reaction was used to genotype them for Val34Leu, Pro564Leu, and Tyr204Phe variants in the FXIII-A subunit gene and for His95Arg variant in the FXIII-B subunit gene. The same variants were analyzed in 102 controls, healthy subjects who were case-matched by age and gender. RESULTS: Genotype distribution for all polymorphisms investigated was not significantly different between cases and controls. Conversely, our CVU cases had a mean ulcer area inversely related with the presence of both Leu34 and Leu564 alleles (ValVal, 12.3 +/- 22.4 cm2 vs LeuLeu, 3.9 +/- 2.6 cm2, P = .002; ProPro, 10.2 +/- 21.2 cm2 vs LeuLeu, 2.9 +/- 1.4 cm2, P = .002). In combined analysis, those cases who were wild-type for both variants (ValVal34/ProPro564) had a further increase in mean ulcer size compared with cases carrying both variants (Leu34/Leu564) (13.3 +/- 27.1 cm2 vs 5.2 +/- 5.6 cm2; P = .034). CONCLUSIONS: No correlation exists between FXIII genotypes and the prevalence of chronic venous ulcers, thus demonstrating that FXIII polymorphisms have no role in ulcer development. In contrast, FXIII-gene variants, in particular the non-wild-type alleles Leu34 and Leu564, were associated with a smaller venous ulcer surface and might have favorable effects on reparative processes.     

Biochemical analysis of wound fluid from nonhealing and healing chronic leg ulcers

The purpose of this study was to determine the biochemical composition of fluid taken from chronic wounds, to compare these values with that of serum, and therefore to assess whether the wound fluid is representative of the extracellular environment of the wound. Paired wound fluid and blood samples were collected from eight patients with chronic leg ulcers in a nonhealing and healing phase. Wound fluid and serum samples were screened for a profile of general biochemical analyses, including electrolytes, lactate, glucose, and protein analyses. Electrolyte levels were essentially identical in wound fluid and serum samples. Lactate and lactate dehydrogenase levels were significantly greater and glucose and bicarbonate levels were significantly lower in wound fluid when compared with the paired serum samples. Albumin and total protein levels in wound fluid were on average half those of serum levels. In this small sample of eight patients, wound fluid collected from chronic leg ulcers is an exudate with the biochemical composition expected in extracellular fluid. In addition, bicarbonate and glucose levels increase and C-reactive protein levels decrease in wound fluid, but remain unchanged in serum, during healing. These results suggest changes in the state of hypoxia and the inflammatory process in the healing wound.     

Urinary transforming growth factor beta-1 as a marker of renal dysfunction in sickle cell disease

Renal dysfunction affects 5–18% of patients with sickle cell disease (SCD). To date, no studies have described urinary levels of transforming growth factor β-1 (TGF-β1), a marker of fibrosis, and neutrophil gelatinase-associated lipocalin (NGAL), a marker of acute/chronic kidney disease, as biomarkers in identifying patients at risk of developing renal disease in SCD. We hypothesized that SCD subjects will have increased urinary excretion of TGF-β1 and NGAL compared with healthy controls (CTR). We examined 51 SCD subjects: 42 HbSS, 8 HbSC, and 1 HbSD. Sixteen out of 42 patients with HbSS were on hydroxyurea (HU). Urinary excretion of TGF-β1 was 26.4 ± 1.5 pg/mgCr in SCD subjects vs 15.0 ± 2.4 pg/mgCr in CTR (p < 0.00001). SCD patients with hemoglobin < 9 g/dl had higher urinary TGF-β1 than patients with milder anemia (p = 0.002). Urinary TGF-β1 trended lower in HbSS patients treated with HU (23.61 ± 2.6 pg/mgCr), vs patients not on HU (27.69 ± 1.8 pg/mgCr; p = 0.055). There was no correlation between urinary TGF-β1 and microalbuminuria or estimated glomerular function. There was no difference in urinary NGAL in SCD patients vs CTR. We suggest that urinary TGF-β1 may serve as a marker of early renal injury in SCD.     

Management of mixed arterial and venous leg ulcers

BACKGROUND: The aim was to assess healing in patients with mixed arterial and venous leg ulcers after protocol-driven treatment in a specialist leg ulcer clinic. METHODS: The study included consecutive patients referred with leg ulceration and venous reflux over 6 years. Legs without arterial disease (ankle : brachial pressure index (ABPI) above 0.85) were treated with multilayer compression bandaging and patients with severe disease (ABPI 0.5 or less) were considered for immediate revascularization. Those with moderate arterial compromise (ABPI above 0.5 up to 0.85) were initially managed with supervised modified compression and considered for revascularization if their ulcer did not heal. Healing rates were determined using life-table analysis. RESULTS: Of 2011 ulcerated legs, 1416 (70.4 per cent) had venous reflux. Of these 1416, 193 (13.6 per cent) had moderate and 31 (2.2 per cent) had severe arterial disease. Healing rates by 36 weeks were 87, 68 and 53 per cent for legs with insignificant, moderate and severe arterial disease respectively (P < 0.001). Seventeen legs with moderate and 15 with severe arterial disease were revascularized. Of these, ulcers healed in four legs with moderate and seven with severe disease within 36 weeks of revascularization (P = 0.270). Combined 30-day mortality for revascularization was 6.5 per cent. CONCLUSION: A protocol including supervised modified compression and selective revascularization achieved good healing rates for mixed arterial and venous leg ulceration.     

Randomized, double-blind, placebo-controlled, dose- ranging study of granulocyte-macrophage colony stimulating factor in patients with chronic venous leg ulcers

Chronic venous leg ulcers are a common ailment with no ideal treatment. Recent reports have shown granulocyte- macrophage colony stimulating factor to be of use in the healing of these chronic wounds. Therefore, we conducted a double-blind, randomized, placebo-controlled study which enrolled 60 patients with chronic venous leg ulcers, whom we treated with placebo or with 200 or 400 microg of granulocyte-macrophage colony stimulating factor by perilesional injections of the drug in four weekly treatment episodes. Observations were conducted at each treatment visit, at weeks 5, 9, 13, and six months after the inclusion in the protocol. The number of healed wounds in the placebo and the treated arms were significantly different (p = 0.05), with 4 of 21 (19%) in the first group having healed at week 13, as compared to 12 of 21 (57%) and 11 of 18 (61%), in the 200 microg and the 400 microg groups, respectively. There were only minor side-effects attributable to the treatment, and the reobservation at 6 months showed that none of the treated ulcers recurred during that period. We conclude that granulocyte-macrophage colony stimulating factor injected perilesionally may be a useful drug for the treatment of chronic venous leg ulcers.