Management of Diabetic Foot Ulcer with MA-ECM (Minimally Manipulated Autologous Extracellular Matrix) Using 3D Bioprinting Technology - An Innovative Approach

Chronic foot ulcers are the leading cause of prolonged hospitalization and loss of social participation in people with diabetes. Conventional management of diabetic foot ulcers (DFU) is associated with slow healing, high cost, and recurrent visits to the hospital. Currently, the application of autologous lipotransfer is more popular, as the regenerative and reparative effects of fat are well established. Herein we report the efficacy of minimally manipulated extracellular matrix (MA-ECM) prepared from autologous homologous adipose tissue by using 3D bioprinting in DFU (test group) in comparison to the standard wound care (control group). A total of 40 subjects were screened and randomly divided into test and control groups. In the test group, the customized MA-ECM was printed as a scaffold from the patient autologous fat using a 3D bioprinter device and applied to the wound directly. The control group received standard wound care and weekly follow-up was done for all the patients. We evaluated the efficacy of this novel technology by assessing the reduction in wound size and attainment of epithelialization. The patients in the test group (n = 17) showed complete wound closure with re-epithelialization approximately within a period of 4 weeks. On the other hand, most of the patients in the control group (n = 16) who received standard wound dressings care showed a delay in wound healing in comparison to the test group. This technique can be employed as a personalized therapeutic method to accelerate diabetic wound healing and may provide a promising potential alternative approach to protect against lower foot amputation a most common complication in diabetes.

The Role of Skin Hardness, Thickness, and Sensory Loss on Standing Foot Power in the Development of Plantar Ulcers in Patients with Diabetes Mellitus—A Preliminary Study

This article presents the results of a study on patients with diabetic neuropathy to find the relationships between the foot pressures characterized by power ratio (PR), foot sole hardness (Shore values), and foot sole soft tissue thickness. The results showed that the increase in PR values for diabetic patients in the upper sensation loss levels (S = 7.5 to 10 g) compared to the corresponding increase in lower sensation loss (S=3 to 4.5 g)were of the order of 5 times in the lateralheel and big toe, respectively, and 4 times in the first metatarsal head regions. The increase in PR values for diabetic patients in the upper Shore value regions (30 to 40) compared to the corresponding increase in lower Shore value regions (20 to 30) were of the order of 3.4 times in lateral heel and 2.4, 2.0, and 2.3 times in the first, second, and lateral metatarsal head regions, respectively. At sites contiguous to frank ulcers for foot sole hardness (Shore values of 50) at sensation level > 10 g PR was as high as 59, and foot sole thickness values were also greater than the corresponding normal values. The study shows all measured parameters may play a part in the development of plantar ulcers.

Biomechanical Properties of the Foot Sole in Diabetic Mellitus Patients

This aricle evaluates and quantifies the biomechanical properties of the foot sole like – loss of protective sensation, hardness of the foot sole and pressure distribution parameter called Power ratio (PR) and its alterations, which have a direct effect on ulcer formation. A new parameter PRS Index is developed to understand the interplay between these parameters and its role in ulcer formation. All diabetic subjects attending the Diabetic foot clinic from Dec2003 to June 2007 undergo a standard foot examination.A total of 652 diabetic patients including 57 ulcer patients are taken for our study. The biomechanical properties include loss of protective sensation (LOPS) which is measured by 10 gm Semmes Weinstein Monofilament (SWMF). Hardness of the foot sole or absence of suppleness is tested using the Durometer (ASTM-D 2240 standards). Plantar pressure measurement is done using the PedoPowerGraph(p) which measures pressure distribution parameter PR. Foot wear properties like hardness of the insole affecting the formation of plantar ulcers was also measured. The above mentioned important parameters can be measured objectively and calculate PRS index value for diabetic with history of previous ulcer patients. We found a single entity of either the PR or shore independently cannot predict the risk for ulcer formation.In this study we found newPRS index value for diabetic with history of previous ulcer patients show significant correlation (i.e. p<0.05 level) between footwear shore and PRS index for history of previous ulcer patients. No significant correlation was shown for diabetic without history of previous ulcer patients and this may be due to diabetic patients are wearing footwear randomly with different degree Shore. From the case studies we found that the PRS index values and other biomechanical parameter of the foot sole can be reversed if the patients wear proper MCR footwear with 20 degree Shore. Use of appropriate footwear has shown that these easily measurable parameters and thus prevent ulcer formation as mentioned in the earlier studies. Several methods are used previously for predicting ulceration in DM patients. But in this study the new index PRS was studied and its role in predicting ulceration. Use of appropriate footwear will reverse the hypertrophic response; this can be quantified by the PRS index. We have found that there is decrease in PRS index by proper off loading the pressure using 20-degree shore MCR footwear.

Correlation between two-point discrimination with other measures of sensory loss in diabetes mellitus patients

Diabetic neuropathy is one of the most important factors for foot ulceration in diabetes mellitus (DM) patients. Among different sensibility measures of neuropathy, two-point discrimination (TPD) has been suggested as a reliable method; however, the correlation of TPD with other well-known measures is not known. We measured the loss of protective sensation using Semmes-Weinstein Monofilaments (SWMF), hardness of the foot sole using shore meter (sh), power ratio (PR) using pedopowergraph and TPD using esthesiometer in foot areas of both left and right legs in 14 DM subjects. We have found no correlation either between TPD and shore values (sh) or between TPD and PR. The SWMF (10 g) is found not to provide any additional value in measuring loss of sensation in comparison to TPD. The TPD appears to be measuring different property of the foot compared to other measures. The mechanism of this independence is not well understood and more investigation is required to understand the mechanism.

Vibration perception threshold and the law of mobility in diabetic mellitus patients

BACKGROUND

Diabetic neuropathy is a family of nerve disorders with progressive loss of nerve function in 15% of diabetes mellitus (DM) subjects. Vibration Perception Threshold (VPT) is one of the modalities of testing loss of protective sensation. Law of mobility for VPT is well known for normal subjects, but not for diabetic subjects. This is a pilot study to evaluate and plot the law of mobility for VPT among DM subjects.

METHODS

We used biothesiometer to find the VPT of several areas in upper and lower extremities for normal and diabetic subjects. VPT of normal and diabetic subjects for different foot areas from proximal to distal is evaluated for 30 subjects. All the subjects are screened for peripheral artery occlusive disease with ankle brachial pressure index (0.9 or above). VPT values of different areas are arranged in a proximal to distal order for the analysis.

RESULTS

VPT values monotonically decrease from proximal to distal areas. Vierodt's law of mobility holds well for normal subjects in both feet areas. The law of mobility does not hold good for the DM subjects in one or both feet areas.

CONCLUSIONS

The VPT value of diabetic subjects reveals that the law of mobility do not holds good for diabetic subjects in foot areas. Though the number of subjects is small, all the subjects defied the law.

Effect of foot sole hardness, thickness and footwear on foot pressure distribution parameters in diabetic neuropathy

This paper presents details of the study undertaken to find the effects of foot sole hardness, thickness and footwear on walking-foot pressure distribution parameters (power ratio (PR)) in diabetic neuropathy. The foot sole hardness is characterized by Shore level. PR represents the ratio of high-frequency power to the total power in the power spectrum of the walking-foot pressure image distribution obtained from the optical pedobarograph. Spatial frequency distributions in the walking-foot pressure images were analysed to calculate the PR in each of the foot sole areas at different levels of foot sole sensation loss and mechanical and geometrical properties. The results show that the increase in PR in the upper foot sole Shore ranges (30-40) is 1.2-2.5 times the corresponding increase in lower Shore ranges (20-30) for some foot sole areas, implying a higher possibility of development of plantar ulcers when combined with deterioration of foot sole sensation. Plantar ulcers are found in feet with foot sole Shore values of 30, a sensation level of 45 mN and PR of 35; for Shore values of 40, sensation levels of 100 mN, with PR 52; and for Shore values above 40, sensation level > 100 mN with PR 58. Providing microcellular rubber insole footwear based on optimum hardness and thickness was found to be helpful in healing plantar ulcers in three to four weeks. Wearing preventive footwear for six months reduced hardness of the foot sole and PR values to near-normal values.

Texture analysis of foot sole soft tissue images in diabetic neuropathy using wavelet transform

The paper presents a new method of characterisation of texture changes in foot sole soft tissue ultrasound (US) images, as observed to occur in diabetic subjects, using wavelet transforms. US images of the soft tissue subcutaneous layer were taken with a 7.5 MHz linear transducer probe placed parallel to the skin surface. The foot sole hardness was characterised by Shore level. A 2D discrete wavelet transform was performed on the US images to extract features that encode the internal state of the foot sole soft tissue. The global energy feature computed at the output of each wavelet channel was found to achieve excellent delineation between the normal and the diabetic groups. An important finding was a strong correlation, in the order of 0.84 and above, between the feature values that reflect changes in the internal arrangement of the tissue, and the externally measurable hardening of the skin, characterised by the Shore levels, with the latter known to be high for diabetics. A comparison drawn between diabetic ulcer and non-ulcer groups established a change in the order of 122-311% in the textural parameter, as influenced by a corresponding 66.7-200% change in the respective Shore values. Thus US examination of foot sole soft tissue and its texture analysis may serve as sources of valuable information regarding the internal changes taking place with progressive hardening of the soft tissue and thereby help the clinician in taking appropriate preventive measures.

New on-line methods for analysis of walking foot pressures in diabetic neuropathy

In this paper, studies are performed on a large number of diabetic patients belonging to different classes, using new on-line foot pressure parameters, i.e. normalized peak pressure (NPP) and pressure contact ratio (PCR), which include effects of the weight of the subject, velocity of walking and duration of high pressures in any region of the foot. A statistical study of the mean maximum value of these parameters in different plantar areas of the feet, for different classes of diabetic subjects, indicates distinguishing trends and hence could aid the clinician in better diagnosis and therapy planning. The NPP and PCR transforms calculated on-line (using specially developed software) help the clinician to quickly determine the heavily loaded foot areas that are potential sites of ulceration in insensitive feet and take the necessary action to prevent further damage to the foot sole.