Differences in localization of P2X7 during epithelial wound healing in pre-type II diabetic models

Corneal injury, accompanied by improper wound repair, is the 4th highest cause of preventable blindness according to the World Health Organization. The cornea, which is the most densely innervated structure in the human body, serves to protect the delicate internal environment of the eye from damage. The integrity of this intricate nerve structure is critical in our ability to sense even the slightest insult to the corneal surface, with reduced sensitivity leading to increased susceptibility to trauma. In diabetes, decreased corneal sensitivity secondary to diabetic peripheral neuropathy can lead to increased corneal abrasion, ulceration, and even blindness. The P2X7 purinoreceptor is an ion channel that is expressed by the epithelium along with the intra-epithelial nerves and stromal nerves. The goal of our study was to use a type 2 diabetic mouse model (DIO) to characterize the changes in P2X7 localization and potentially correlate our results with changes in trafficking and sensory nerve loss. We hypothesized that the P2X7 receptor acts to sense changes at the leading edge and this fine tuned regulation is altered during the diabetic disease state. Further understanding of the corneal changes that occur in diabetes can help us better monitor progression of diabetic complications as well as develop new therapeutics for the treatment of diabetic corneal dysfunction

The effect of diabetes on fracture repair : alterations in angiogenesis and apoptosis

Thesis (MSD)--Boston University, Goldman School of Dental Medicine, 2007 (Endodontics).Includes bibliographical references: leaves 56-65.An abundance of evidence has emerged demonstrating a close link between diabetes and significantly impaired fracture healing. Previous studies have determined that repair of fractures in diabetic animals is characterized by calluses with decreased size and bone formation. To further investigate the possible reasons for the decreased callus size we undertook a detailed histologic and immunohistochemical analysis focusing on the apoptosis of bone cells and angiogenesis that occurs during fracture healing. Angiogenesis was determined in the fractures by quantitative immunohistochemical analysis using the antibody to CD34. Cells expressing CD34 are found in the endothelial lining of blood vessels. Apoptotic cells were stained using the Apoptag Peroxidase In Situ Apoptosis Detection Kit. The decision to target these two parameters was based on the concept that enhanced cell death and decreased angiogenesis may limit the repair process. We used a well characterized type 1 diabetic animal model; the streptozotocin induced diabetic mouse (n=8), and a nondiabetic control group (n=7). Three weeks after establishing diabetes, tibia fractures were induced. The mice were euthanized 12, 16 and 22 days after fracture. The 16 day samples were processed, embedded, sectioned and stained for analysis. The size of the fracture callus, and the amount of new bone and cartilage were determined using slides stained with H&E, masson trichrome and safranin-O/fast green, respectively. The results showed that the diabetic groups have statistically two fold more apoptotic cells per callus (p<0.05). We also found that the number of vessels located in the areas of immature new bone were twice as high in the normal group [TRUNCATED

Cardiovascular/Stroke Risk Stratification in Diabetic Foot Infection Patients Using Deep Learning-Based Artificial Intelligence: An Investigative Study

A diabetic foot infection (DFI) is among the most serious, incurable, and costly to treat conditions. The presence of a DFI renders machine learning (ML) systems extremely nonlinear, posing difficulties in CVD/stroke risk stratification. In addition, there is a limited number of well-explained ML paradigms due to comorbidity, sample size limits, and weak scientific and clinical validation methodologies. Deep neural networks (DNN) are potent machines for learning that generalize nonlinear situations. The objective of this article is to propose a novel investigation of deep learning (DL) solutions for predicting CVD/stroke risk in DFI patients. The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) search strategy was used for the selection of 207 studies. We hypothesize that a DFI is responsible for increased morbidity and mortality due to the worsening of atherosclerotic disease and affecting coronary artery disease (CAD). Since surrogate biomarkers for CAD, such as carotid artery disease, can be used for monitoring CVD, we can thus use a DL-based model, namely, Long Short-Term Memory (LSTM) and Recurrent Neural Networks (RNN) for CVD/stroke risk prediction in DFI patients, which combines covariates such as office and laboratory-based biomarkers, carotid ultrasound image phenotype (CUSIP) lesions, along with the DFI severity. We confirmed the viability of CVD/stroke risk stratification in the DFI patients. Strong designs were found in the research of the DL architectures for CVD/stroke risk stratification. Finally, we analyzed the AI bias and proposed strategies for the early diagnosis of CVD/stroke in DFI patients. Since DFI patients have an aggressive atherosclerotic disease, leading to prominent CVD/stroke risk, we, therefore, conclude that the DL paradigm is very effective for predicting the risk of CVD/stroke in DFI patients

Transcutaneous Oximetry (tcpO2) A study to Evaluate the Clinical Role of tcpO2 in the Vascular Patient Cohort and in Particular Those Patients with Foot Ulceration.

Introduction: Ulceration is defined as a breakdown of the skin. The treament of ulcers can be difficult and both time and cost expensive for the patient and health service. Determining what has caused this ulceration and formulating a treatment plan is key. There is no one universally accepted test which can accurately predict if a wound will heal or what treatment will be successful in healing it. Assessing the peripheral arterial system is an important first test to ensure that there is adequate blood perfusion to the ulcerated area. This is carried out by performing a test called Toe Brachial Indices (TBI’s). In 2012 a new test called transcutaneous oximetry (tcpO2) was introduced to the vascular laboratory service in a bid to gain extra information on ulcer diagnosis and potential healing status. This test examines tissue oxygenation levels at a particular site. The purpose of this audit is to determine if tcpO2 provides any additional diagnostic information. Method: From its introduction in 2012 and for the following three years all results of this test and a set of TBI’s were audited. Patients who presented to the vascular service with an active foot ucleration had both tests performed. A medical history was taken to record the risk factors of peripheral arterial disease. Results: There were a total of 247 patients included in the audit which equated to 310 tests for anaylsis (a number of patients had tests performed on both feet). The age range was 32 – 94 years old with a mean age of 67.5 years and a median age of 69 years. Both tests were compared. tcpO2 and TBI’S were statistically lower in the smokers in comparision to the non smokers. Absolute toe pressures were statistically lower in the patients on statins and antihypertensives when compared to those not. Nether of these areas are well researched. When all test results were compared 70% of tests had reduced TBI results indicating arterial disease. Of this 70%, 39% had a tcpO2 result which was below a normal threshold suggestive that spontaneous healing was not likely to occur. This group with low TBI’s and low tcpO2 had significant numbers of interventions and amputations. More interestingly, the remaining 31% of tests had a tcpO2 test outcome which was above the normal threshold suggestive of spontaneous healing. These tests required a lower number of interventions and amputations when compared to the tests where both results are normal. Conclusion: In the setting of peripheral arterial disease the addition of tcpO2 does provide additional further diagnostic information that should be taken into consideration with a TBI result when treating foot ulceration. In the absence of a TBI result it is reasonable to consider a tcpO2 test as an alternative source of diagnostic information

The Impact of Diabetic Conditions and AGE/RAGE Signaling on Cardiac Fibroblast Migration

© Copyright © 2020 Burr, Harmon and Stewart. Diabetic individuals have an increased risk for developing cardiovascular disease due to stiffening of the left ventricle (LV), which is thought to occur, in part, by increased AGE/RAGE signaling inducing fibroblast differentiation. Advanced glycated end-products (AGEs) accumulate within the body over time, and under hyperglycemic conditions, the formation and accumulation of AGEs is accelerated. AGEs exert their effect by binding to their receptor (RAGE) and can induce myofibroblast differentiation, leading to increased cell migration. Previous studies have focused on fibroblast migration during wound healing, in which diabetics have impaired fibroblast migration compared to healthy individuals. However, the impact of diabetic conditions as well as AGE/RAGE signaling has not been extensively studied in cardiac fibroblasts. Therefore, the goal of this study was to determine how the AGE/RAGE signaling pathway impacts cell migration in non-diabetic and diabetic cardiac fibroblasts. Cardiac fibroblasts were isolated from non-diabetic and diabetic mice with and without functional RAGE and used to perform a migration assay. Cardiac fibroblasts were plated on plastic, non-diabetic, or diabetic collagen, and when confluency was reached, a line of migration was generated by scratching the plate and followed by treatment with pharmacological agents that modify AGE/RAGE signaling. Modification of the AGE/RAGE signaling cascade was done with ERK1/2 and PKC-ζ inhibitors as well as treatment with exogenous AGEs. Diabetic fibroblasts displayed an increase in migration compared to non-diabetic fibroblasts whereas inhibiting the AGE/RAGE signaling pathway resulted in a significant increase in migration. The results indicate that the AGE/RAGE signaling cascade causes a decrease in cardiac fibroblast migration and altering the pathway will produce alterations in cardiac fibroblast migration

Diabete Mellito e Lenti a Contatto. Diabetes Mellitus and Contact Lenses

This work on Diabetes Mellitus and Contact Lenses had two main purposes: the first was to review a moderate part of the literature about this field of interest, preceded by a short review on cornea and its alterations as Diabetes Mellitus occurs. The second target was to conduct a small survey among Italian diabetics and healthy subjects who wore contact lenses. The aim of the survey was to find if the results would have agreed with the previous review. The analysis based on the survey, conducted by giving the same questionnaires to healthy and diabetic subjects, was not prospective as all the interviewed were already wearing contact lenses or had worn them before. In particular, the survey was based on some parts of Efron’s survey, made among diabetic patients and practitioners in the UK in 1997. In addition to this, the results of the survey were compared with other considerations, which emerged during the review. The aim of the questionnaire was to find out if RGP contacts were used in higher percentage among diabetics rather than in healthy subjects, and to see if diabetics had higher rate of drop out or interruptions in contact lenses’ use due to discomfort or dry eye. The method used for the retrospective survey consisted in proposing 39 anonymous questionnaires, of which 20 were proposed to healthy contact lenses’ users and 19 to diabetics; of them only 9 wore contacts. Finding diabetic contact lenses’ users was pointed out as the main struggle for the success of the survey. The questionnaires were analysed with the percentage on the amounts of answers. The results showed that 45% of diabetics used RGP CLs against the 10% of the healthy subjects, meaning that RGP were preferred for diabetic corneas, even if the reasons of this choice were not asked. For what concerns interruption of contacts lenses, none of the healthy subjects interrupted CLs because of dry eye, the 10% of them interrupted because of discomfort, while among people affected by Diabetes Mellitus 11% dropped because of dry eye and another 11% dropped because of discomfort. These results are in agreement with literature, even if there are some limitations that can compromise the accuracy of the data: firstly, the samples consisted in a small amount of people, increasing the errors’ rate due to comprehension of the questions and accuracy in the answers. Another limitation was the subjective nature of the data, as no objective measurements were collected during the survey. Moreover, the samples came from two Italian regions (Veneto and Friuli Venezia Giulia), which means that the survey is not representative of the Italian population. In conclusion, further analysis would be necessary to confirm the results of this survey. The main considerations achieved by reviewing literature were that Diabetes Mellitus not only afflicts the retina (causing Diabetic Retinopathy) but also the corneal tissue. Indeed, it causes abnormalities in all corneal layers giving fragility, slower times of recovery from both epithelial and endothelial oedema, disfunctions in Na+/K+-ATPase’s pump and faster aging. Furthermore, the storage of glucose and sorbitol during hyperglycaemia and chronic hyperglycaemia can lead to alterations on the tissue’s transparency causing blurred vision and to refractive changes, which can sway from hyperopia to myopia very easily. Finally, diabetic eyelids are more prone to infections. If these infections become chronic then contact lenses are not to recommend to the person affected by Diabetes Mellitus. The alterations listed above summarize why Diabetes Mellitus is a relevant but relative contra-indication to contact lenses’ use: the practitioner should take in consideration the clinical picture of the diabetic cornea and decide if whether or not prescribe contact lenses, especially if the subject hardly follows the prescriptions given by the specialist.ope

Amputation stump perfusion is predictive of post-operative necrotic eschar formation

BACKGROUND: A large proportion of patients develop poor amputation stump healing. We hypothesize that Laser-Assisted Fluorescent Angiography (LAFA) can predict inadequate tissue perfusion and healing. METHODS: Over an 8-month period we reviewed all patients who underwent lower extremity amputation and LAFA. We evaluated intra-operative LAFA global and segmental stump perfusion, and post-operative modified Bates-Jensen (mBJS) wound healing scores. RESULTS: In 15 patients, amputation stumps with lower global perfusion demonstrated higher mBJS (P = 0.01). Lower suture-line perfusion also correlated with more eschar formation (P \u3c 0.001). Diabetic patients had higher mBJS (P = 0.009), lower stump perfusion (P = 0.02), and increased eschar volume (P \u3c 0.001). CONCLUSION: LAFA is a useful adjunct for intra-operative stump perfusion assessment and can predict areas of poor stump healing and eschar formation. Diabetic patients seem to be at higher risk of stump eschar formation

Global Perspective on Diabetic Foot Ulcerations

Over the last decade, it is becoming increasingly clear that diabetes mellitus is a global epidemic. The influence of diabetes is most readily apparent in its manifestation in foot complications across cultures and continents. In this unique collaboration of global specialists, we examine the explosion of foot disease in locations that must quickly grapple with both mobilizing medical expertise and shaping public policy to best prevent and treat these serious complications. In other areas of the world where diabetic foot complications have unfortunately been all too common, diagnostic testing and advanced treatments have been developed in response. The bulk of this book is devoted to examining the newest developments in basic and clinical research on the diabetic foot. It is hoped that as our understanding of the pathophysiologic process expands, the devastating impact of diabetic foot complications can be minimized on a global scale

Detecting Bacteria on Wounds with Hyperspectral Imaging in Fluorescence Mode

Chronic non-healing wounds represent an increasing problem. In order to enable physicians and nurses to make evidence based decisions on wound treatment, the professional societies call for supporting tools to be offered to physicians. Oxygen supply, bacteria colonization and other parameters influence the healing process. So far, these parameters cannot be monitored in an objective and routinely manner. Existing methods like the microbiological analysis of wound swabs, mean a great deal of effort and partly a long delay. In this paper 42 fluorescence images from 42 patients with diabetic foot ulcer, recorded with a hyperspectral imaging system (TIVITA®), converted for fluorescence imaging, were analysed. Beside the fluorescence images, information about the bacterial colonization is available from microbiological analysis of wound swabs. After preprocessing, principal component analysis, PCA, is used for data analysis with a 405 nm excitation wavelength, the emission wavelength range 510 - 745 nm is used for analysis. After dividing the data into a training and a test dataset it could be shown, that bacteria are detectable in the wound area. A quantification in bacterial colonization counts (BCC) was not in the focus of the research in this study stage

Localization and patterning of pannexin-1 in pre-diabetic murine corneal epithelial tissue after injury

Type II diabetes is a major cause of blindness according to the World Health Organization (WHO, 2018). Diabetics are at risk of developing corneal diseases such as recurrent abrasions, ulcers, and erosions due to dysfunctional wound healing. Corrective surgeries or corneal transplants may be considered as a treatment in some, but not all, cases. The purinoreceptor P2X7 has been shown to be involved in cell-cell communication and in the restructuring of cytoskeletal actin, a necessary process for cell migration in wound healing. P2X7 relies on the binding of extracellular ATP for activation. Panx1 is a transmembrane protein whose primary role is for the release of intracellular ATP into the extracellular space. In healthy corneal epithelium, Panx1 localizes to the wound edge and forms clusters with the P2X7, which augments the wound healing response. This thesis looks at the localization of Panx1 in pre-diabetic murine corneal tissue. It was found that Panx1 is less expressed and does not localize to the wound edge to the extent as control corneas, therefore, creating less clusters with P2X7. Furthermore, preliminary studies that inhibit Panx1 with probenecid reduce the communication between cells, which is hypothesized as critical for migration of the tissue sheet and proper wound healing.2019-12-17T00:00:00