Prognostic factors predicting ischemic wound healing following hyperbaric oxygenation therapy

Photoacoustic monitoring of angiogenesis predicts response to therapy in healing wounds

Chronic wounds are a major health problem that cause the medical infrastructure billions of dollars every year. Chronic wounds are often difficult to heal and cause significant discomfort. Although wound specialists have numerous therapeutic modalities at their disposal, tools that could three dimensional-map wound bed physiology and guide therapy do not exist. Visual cues are the current standard but are limited to surface assessment; clinicians rely on experience to predict response to therapy. Photoacoustic (PA) ultrasound (US) is a non-invasive, hybrid imaging modality that can solve these major limitations. PA relies on the contrast generated by haemoglobin in blood which allows it to map local angiogenesis, tissue perfusion and oxygen saturation-all critical parameters for wound healing. This work evaluates the use of PA-US to monitor angiogenesis and stratify patients responding versus not-responding to therapy. We imaged 19 patients with 22 wounds once a week for at least 3 weeks. Our findings suggest that PA imaging directly visualises angiogenesis. Patients responding to therapy showed clear signs of angiogenesis and an increased rate of PA increase (p = 0.002). These responders had a significant and negative correlation between PA intensity and wound size. Hypertension was correlated to impaired angiogenesis in non-responsive patients. The rate of PA increase and hence the rate of angiogenesis was able to predict healing times within 30 days from the start of monitoring (power = 88%, alpha = 0.05). This early response detection system could help inform management and treatment strategies while improving outcomes and reducing costs.

Determinants of wound healing in patients hospitalized for diabetic foot ulcer: results from the MEDFUN study

OBJECTIVE

The high amputation rates from diabetic foot ulcer (DFU) in Nigeria and prolonged hospitalization due to poor wound healing is a source of concern. Furthermore, factors that affect wound healing of DFUs have not yet been well studied in Nigeria, whereas knowing these factors could improve DFU outcomes. Therefore, the objective of this study was to determine the factors that are associated with the wound healing in patients hospitalized for DFU.

METHODS

The Multi-Center Evaluation of Diabetic Foot Ulcer in Nigeria (MEDFUN) was an observational study involving 336 diabetic patients hospitalized for DFU and managed by a multi-disciplinary team until discharge or death. Demographic, clinical, and biochemical characteristics were documented. Test statistics used were chi square, t-test, univariate, and multivariate logistic regression. The study endpoints were ulcer healing, LEA, duration of hospitalization, and mortality. Here we present data on wound healing.

RESULTS

The mean ± SD age was 55.9±12.5 years. Univariate predictors of wound healing were ulcer duration more than 1 month prior to hospitalization (p<0.001), peripheral arterial disease (PAD) (p<0.001), foot gangrene (p<0.001), Ulcer grade ≥3 (p=0.002), proteinuria (p=0.005), anemia (p=0.009), renal impairment (p=0.021), glycated hemoglobin ≥7% (0.012), and osteomyelitis (p<0.001). On multivariate regression, osteomyelitis was the strongest independent predictor of wound healing after adjusting for all other variables (OR 0.035; 95% CI 0.004-0.332). This was followed by PAD (OR 0.093; 95% CI 0.028-0.311), ulcer duration >1 month (OR 0.109; 95% CI 0.030-0.395), anemia (OR 0.179; 95% CI 0.056-0.571).

CONCLUSION

Presence of osteomyelitis, duration of ulcer greater than 1 month, PAD, Wagner grade 3 or higher, proteinuria, presence of gangrene, anemia, renal impairment, and HbA1c ≥7% were the significant predictors of wound healing in patients hospitalized for DFU. Early identification and prompt attention to these factors in a diabetic foot wound might significantly improve healing and reduce adverse outcomes such as amputation and death.

Amputation predictors in diabetic foot ulcers treated with hyperbaric oxygen

OBJECTIVE

Although hyperbaric oxygen therapy (HBOT) has long been used for diabetic foot ulcers (DFUs), its effectiveness is still controversial. The aim of this study was to investigate the efficacy of HBOT in the management of DFUs and identify amputation predictors.

METHOD

Patients with chronic DFUs (Wanger grade 2-5) were included in the study, which took place between January 2010 and December 2012. HBOT, 100% oxygen, 2.4 atmosphere absolute (ATA) for 120 minutes, was administered to all patients in addition to standard treatment. DFUs were monitored for at least 3 years, or until healing or amputation occurred.

RESULTS

Patients with a total of 146 chronic DFUswere recruited. Complete healing (69.6%) and significant improvement (17.9%) was observed in 87.5% of the patients. The cases with no improvement resulted in amputation (minor amputation: 15.0%; major amputation: 8.2%). The duration of diabetes (p=0.037), new wound formation (p=0.045), C-reactive protein (p=0.001) and Wagner grade (p=0.0001) were correlated with amputation in multiple regression analysis. Mortality was higher in the amputation group than in the non-amputation group (47.1 % versus 21.4 %, p=0.007).

CONCLUSION

The inclusion of HBOT with standard treatment and a multidisciplinary approach may be useful in the treatment of DFUs. We found the most important predictors of amputation to be Wagner grade and wound infection. Multicentre, prospective, randomised studies are needed to provide more evidence.

Hypoxia in Obesity and Diabetes: Potential Therapeutic Effects of Hyperoxia and Nitrate

The prevalence of obesity and diabetes is increasing worldwide. Obesity and diabetes are associated with oxidative stress, inflammation, endothelial dysfunction, insulin resistance, and glucose intolerance. Obesity, a chronic hypoxic state that is associated with decreased nitric oxide (NO) bioavailability, is one of the main causes of type 2 diabetes. The hypoxia-inducible factor-1α (HIF-1α) is involved in the regulation of several genes of the metabolic pathways including proinflammatory adipokines, endothelial NO synthase (eNOS), and insulin signaling components. It seems that adipose tissue hypoxia and NO-dependent vascular and cellular dysfunctions are responsible for other consequences linked to obesity-related disorders. Although hyperoxia could reverse hypoxic-related disorders, it increases the production of reactive oxygen species (ROS) and decreases the production of NO. Nitrate can restore NO depletion and has antioxidant properties, and recent data support the beneficial effects of nitrate therapy in obesity and diabetes. Although it seems reasonable to combine hyperoxia and nitrate treatments for managing obesity/diabetes, the combined effects have not been investigated yet. This review discusses some aspects of tissue oxygenation and the potential effects of hyperoxia and nitrate interventions on obesity/diabetes management. It can be proposed that concomitant use of hyperoxia and nitrate is justified for managing obesity and diabetes.