The association between skin blood flow and edema on epidermal thickness in the diabetic foot

Opening a window to skin biomarkers for diabetes stage with optoacoustic mesoscopy

Being the largest and most accessible organ of the human body, the skin could offer a window to diabetes-related complications on the microvasculature. However, skin microvasculature is typically assessed by histological analysis, which is not suited for applications to large populations or longitudinal studies. We introduce ultra-wideband raster-scan optoacoustic mesoscopy (RSOM) for precise, non-invasive assessment of diabetes-related changes in the dermal microvasculature and skin micro-anatomy, resolved with unprecedented sensitivity and detail without the need for contrast agents. Providing unique imaging contrast, we explored a possible role for RSOM as an investigational tool in diabetes healthcare and offer the first comprehensive study investigating the relationship between different diabetes complications and microvascular features in vivo. We applied RSOM to scan the pretibial area of 95 participants with diabetes mellitus and 48 age-matched volunteers without diabetes, grouped according to disease complications, and extracted six label-free optoacoustic biomarkers of human skin, including dermal microvasculature density and epidermal parameters, based on a novel image-processing pipeline. We then correlated these biomarkers to disease severity and found statistically significant effects on microvasculature parameters as a function of diabetes complications. We discuss how label-free RSOM biomarkers can lead to a quantitative assessment of the systemic effects of diabetes and its complications, complementing the qualitative assessment allowed by current clinical metrics, possibly leading to a precise scoring system that captures the gradual evolution of the disease.

Subepidermal Low-Echogenic Band-Its Utility in Clinical Practice: A Systematic Review

High-frequency ultrasonography (HF-USG) is a relatively new imaging method that allows the evaluation in a non-invasive manner of the skin layers and skin appendages. It is a diagnostic tool with increasing usefulness in numerous dermatological pathologies. High reproducibility, non-invasiveness and short diagnostic time make this method an increasingly used tool in dermatological practice. The subepidermal low-echogenic band is a relatively newly described parameter that seems to be a marker not only of intrinsic and extrinsic skin aging, but also of inflammatory processes taking place at the skin level. This systematic review aims to evaluate the role that SLEB has in the diagnosis and monitoring of the treatment of some inflammatory and non-inflammatory dermatological conditions, as well as its utility as a disease marker.

Albuminuric diabetic kidney disease predicts foot ulcers in type 2 diabetes

Diabetic Foot Ulcers (DFU) are feared among individuals with diabetic kidney disease (DKD), but it is unclear whether they are more frequent, especially in normoalbuminuric DKD. Five hundred and twenty patients admitted in our diabetology ward from 2007 to 2017 were followed up during 54 ± 26 months. New DFUs were registered, and their relationship with the initial renal status was analyzed by LogRank and multivariate Cox regression analysis. The 520 subjects were mainly men (57.9 %), 62 ± 9 years old, with a duration of diabetes of 14 ± 10 years, HbA1c: 8.7 ± 1.8 % (72 ± 19 mmol/mol), and complications: 33.7 % macroangiopathies, 22.1 % previous foot ulcers, 44.8 % DKD, 26.9 % retinopathies. Fifty-seven new DFU occurred, mainly in subjects with DKD. DKD was related to later DFU (HR: 1.79; 95%CI: 1.05-3.07), this relationship stayed significant adjusted for age, gender, and a history of previous DFU (HR: 3.61; 95%CI: 2.11-6.18), and further adjusted for the duration of diabetes, HbA1c, BMI, arterial hypertension, and dyslipidemia. Among the 233 subjects with DKD, 129 (55.3 %) had an isolated AER > 30 mg/24H, 41 (17.6 %) had an isolated eGFR<60 mL/min/1.73 m², and 63 (27.0 %) cumulated both abnormalities. By Cox regression analysis adjusted for age and gender, albuminuric DKDs were related to later DFU: with eGFR≥60: HR: 1.91; 95%CI: 1.02-3.59, with eGFR<60: HR: 2.53; 95%CI: 1.25-5.10, whereas normoalbuminuric DKD was not: HR: 1.04; 95%CI: 0.35-3.07, despite similar rates of neuropathies, peripheral arterial diseases, and retinopathies. In people with type 2 diabetes, albuminuric DKD was associated with two to three folds increased risk of DFUs, whereas normoalbuminuric DKD was not.

Autologous wound margin point columnar full‐thickness skin grafting combined with negative pressure wound therapy improves wound healing in refractory diabetic foot ulcers

Diabetic lower extremity ulcers (DLEUs) are a severe complication of diabetes mellitus (DM) and are difficult to heal. This study aimed to explore the efficacy of autologous point columnar full-thickness skin graft taken from the ulcer wound margin combined with negative pressure wound therapy (NPWT) in refractory DLEUs. This is a prospective cohort study. A total of 40 inpatients with refractory DLEUs were recruited in the Diabetes Foot Center of Guangxi Zhuang Autonomous Region People's Hospital from October 2019 to November 2021. According to the doctors' professional suggestions and the patients' personal wishes, these enrolled patients were divided into two groups based on different topical wound management: the graft group (n = 18) and the conventional wound therapeutic (CWT) group (n = 22). The efficacy evaluations included the time to complete re-epithelialization of the wound and healing speed within 14 days of graft treatment or after 14 days of graft treatment in the two groups. Before the treatment, the graft group had a significantly larger ulcer area than the CWT group [27.22 (15.28, 46.59) versus 10.92 (7.00, 24.93) cm² , P < .01]. However, the time to complete wound re-epithelialization in the graft group was shorter than in the CWT group [58.22 ± 30.60 versus 86.09 ± 49.54 d, P < .05]. Meanwhile, the healing speed in graft group was markedly faster than in CWT group, whether within 14 days [0.60 (0.40, 0.92) versus 0.16 (0.07, 0.34) cm² /d, P < .01] or after 14 days of graft treatment [0.57 (0.45, 0.91) versus 0.13 (0.08, 0.27) cm² /d, P < .01]. However, the total treatment cost in the graft group was lower than in the CWT group [419.59 ± 137.20 versus 663.97 ± 497.02 $, P < .05]. The novel treatment modality of autologous full-thickness skin graft taken from the ulcer wound margin combined with NPWT has hereby proposed for the first time, and is a safe, effective, and reliable method with a good performance-to-cost ratio to promote wound healing and shorten the healing time for DLEUs.

Vascular ageing and peripheral pulse: an improved model for assessing their relationship

Objective.Vascular ageing is associated with several alterations, including arterial stiffness and endothelial dysfunction. Such alterations represent an independent factor in the development of cardiovascular disease (CVD). In our previous works we demonstrated the alterations occurring in the vascular system are themselves reflected in the shape of the peripheral waveform; thus, a model that describes the waveform as a sum of Gaussian curves provides a set of parameters that successfully discriminate betweenunder(≤35 years old) andoversubjects (>35 years old). In the present work, we explored the feasibility of a new decomposition model, based on a sum of exponential pulses, applied to the same problem.Approach.The first processing step extracts each pulsation from the input signal and removes the long-term trend using a cubic spline with nodes between consecutive pulsations. After that, a Least Squares fitting algorithm determines the set of optimal model parameters that best approximates each single pulse. The vector of model parameters gives a compact representation of the pulse waveform that constitutes the basis for the classification step. Each subject is associated to his/her 'representative' pulse waveform, obtained by averaging the vector parameters corresponding to all pulses. Finally, a Bayesan classifier has been designed to discriminate the waveforms of under and over subjects, using the leave-one-subject-out validation method.Main results.Results indicate that the fitting procedure reaches a rate of 96% in under subjects and 95% in over subjects and that the Bayesan classifier is able to correctly classify 91% of the subjects with a specificity of 94% and a sensibility of 84%.Significance.This study shows a sensible vascular age estimation accuracy with a multi-exponential model, which may help to predict CVD.

Plantar soft tissues and Achilles tendon thickness and stiffness in people with diabetes: a systematic review

BACKGROUND

Diabetes mellitus is associated with changes in soft tissue structure and function. However, the directionality of this change and the extent to which either tissue thickness or stiffness contributes to the pathogenesis of diabetes-related foot ulcerations is unclear. Hence, this systematic review aims to summarise the existing evidence for soft tissue structural differences in the feet of people with and without diabetes.

METHODS

In compliance with MOOSE and PRISMA guidelines, AMED, CINAHL, MEDLINE, ProQuest Health & Medical Collection, ProQuest Nursing & Allied Health Database, and Web of Science electronic databases were systematically searched for studies published from database inception until 1st October 2020 [Prospero CRD42020166614]. Reference lists of included studies were further screened. Methodological quality was appraised using a modified critical appraisal tool for quantitative studies developed by McMaster University.

RESULTS

A total of 35 non-randomised observational studies were suitable for inclusion. Within these, 20 studies evaluated plantar tissue thickness, 19 studies evaluated plantar tissue stiffness, 9 studies evaluated Achilles tendon thickness and 5 studies evaluated Achilles tendon stiffness outcomes. No significant differences in plantar tissue thickness were found between people with and without diabetes in 55% of studies (11/20), while significantly increased plantar tissue stiffness was found in people with diabetes in 47% of studies (9/19). Significantly increased Achilles tendon thickness was found in people with diabetes in 44% of studies (4/9), while no significant differences in Achilles tendon stiffness were found between people with and without diabetes in 60% of studies (3/5).

CONCLUSIONS

This systematic review found some evidence of soft tissue structural differences between people with and without diabetes. However, uncertainty remains whether these differences independently contribute to diabetes-related foot ulcerations. The heterogeneity of methodological approaches made it difficult to compare across studies and methodological quality was generally inadequate. High-quality studies using standardised and validated assessment techniques in well-defined populations are required to determine more fully the role of structural tissue properties in the pathogenesis of diabetes-related foot ulcerations.

3D Printing Silicone Elastomer for Patient-Specific Wearable Pulse Oximeter

Commercial pulse oximeters are used clinically to measure heart rate and blood oxygen saturation and traditionally made from rigid materials. However, these devices are unsuitable for continuous monitoring due to poor fit and mechanical mismatch. Soft materials that match the elastic properties of biological tissue provide improved comfort and signal-to-noise but typically require molding to manufacture, limiting the speed and ease of customizing for patient-specific anatomy. Here, freeform reversible embedding (FRE) 3D printing is used to create polydimethylsiloxane (PDMS) elastomer cuffs for use on the hand and foot. FRE enables printing liquid PDMS prepolymer in 3D geometries within a sacrificial hydrogel bath that provides support during cure. This serves as proof-of-concept for fabricating patient-specific pulse oximeters with pressure sensing, termed P³ -wearable. A sizing analysis establishes dimensional accuracy of FRE-printed PDMS compared to anatomical computer-aided design models. The P³ -wearable successfully outputs photoplethysmography (PPG) and pressure amplitude signals wirelessly to a tablet in real time and the PPG is used to calculate heart rate, blood oxygen content, and activity state. The results establish that FRE printing of PDMS can be used to fabricate patient-specific wearable devices and measure heart rate and blood oxygenation on par with commercial devices.

Optical Coherence Tomography Angiography for Evaluation of Reperfusion After Pterygium Surgery

PURPOSE

To describe the use of optical coherence tomography angiography (OCTA) to quantitatively monitor the conjunctival graft revascularization after pterygium excision and conjunctival autograft (CAG) transplantation.

DESIGN

Prospective, interventional case series.

METHODS

Ten patients undergoing pterygium excision and femtosecond laser-assisted CAG transplantation were included. OCTA was performed at 1 week, 1 and 3 months postoperatively at the CAG transplantation site and harvested area. The vessel density at three different depths: conjunctival epithelium or CAG epithelium, conjunctival stroma or CAG stroma, and episclera, was evaluated and quantified. The revascularization rate was assessed and correlated with the postoperative CAG thickness.

RESULTS

No intraoperative and postoperative complications occurred. Reperfusion of the CAGs was observed at 1 week, and early reperfusion within the first month accounted for more than half of graft revascularization. The vessel regrowth density was 9.6±2.6 % and 11.1±2.8 % between 1 week and 1 month, and was 9.8±1.8 % and 11.9±1.9 % between 1 and 3 months, at the CAG and underlying episcleral levels, respectively. All the CAGs were well-perfused at 3 months. The vessel regrowth density was significantly and strongly correlated with the changes of CAG thickness in a negative relationship (γ = -0.94, P = 0.019). At the harvested site, the vascular network of episclera was not affected, and the conjunctival vascularization was restored at 1 month.

CONCLUSIONS

OCTA is a promising tool to evaluate the vascularization or revascularization of conjunctiva, conjunctival graft and episclera, in a quantitative and serial manner, helping in diseases diagnosis and treatment monitoring. The graft revascularization rate was predictive of postoperative graft deswelling.

Possible applications of normative lower to upper limb ratios of tissue dielectric constant to lower extremity edema

BACKGROUND

Lower extremity edema occurs in many conditions including congestive heart failure, lymphedema, diabetes-related, kidney and liver disease, chronic venous insufficiency with venous hypertension. Clinical edema assessment methods are often subjective and variable. Our goals were to introduce a simple noninvasive measurement procedure potentially useful to characterize lower extremity edema by providing normative values from which edema thresholds might emerge.

METHODS

Tissue dielectric constant (TDC) values, as indices of skin-to-fat tissue water, were measured on foot dorsum, lower medial leg and anterior forearm of 88 adults (44 female) with ages ranging from 19-77 years with BMI ranging from 18.3-40.6 kg/m2. From these direct measurements lower-to-upper extremity TDC ratios (foot/arm and leg/arm) were determined for each gender. Possible edema threshold ratios were calculated as the mean lower-to-upper ratio to which was added two standard deviations of the overall ratio thereby providing initial thresholds for future testing.

RESULTS

Results showed that at each anatomical site absolute TDC values for males significantly exceed those of females (P<0.001). Male vs. female TDC values were 33.0±5.4 vs. 27.7±4.0 for the forearm, 34.8±6.5 vs. 27.5±4.6 for the leg, and 32.5±6.5 vs. 28.7±5.1 for the foot. In contrast, the foot/arm and leg/arm ratios were similar between genders ranging 0.990±0.144 to 1.063±0.170. Corresponding lower extremity to upper extremity threshold ratios ranged from 1.278 for foot/arm to 1.403 for leg/arm. The composite ratios considering both gender ration (N.=88) yielded a composite threshold foot/arm ratio of 1.387 and a leg/arm threshold ratio of 1.324.

CONCLUSIONS

This assessment method together with the normative ratios and calculated thresholds may aid in rapid detection of lower extremity edema in patients and possibly as a way to quantitatively track changes in edema status with time or treatment. However, the suitability of these thresholds is subject to future validation in persons with clearly defined lower extremity edema for which this report's findings serve as an initial quantitative starting point.

A Quantitative Method to Measure Skin Thickness in Leg Edema in Pregnant Women Using B-Scan Portable Ultrasonography: A Comparison Between Obese and Non-Obese Women

BACKGROUND This study aimed to use a portable ultrasound method to quantitatively measure skin thickness and to compare leg edema in obese and non-obese pregnant women. MATERIAL AND METHODS Thirty-six pregnant women (17 primiparas and 19 multiparas) at 27/28 and 37/38 weeks of pregnancy, with and without leg edema, had their lower leg skin thickness measured using a B-scan portable ultrasonography device (72 legs and maximum of 98 measurements). Measurements were compared between women who were obese prior to pregnancy, with a body mass index (BMI) ≥25 kg/m² and non-obese with a BMI <25 kg/m². RESULTS Skin thickness of the legs in pregnant women with edema was significantly increased compared with that in pregnant women without edema (6.4±0.3 mm vs. 4.6±0.4 mm) (p=0.0001). There was a significant correlation between the degree of pitting edema and skin thickness in all edematous legs (r=0.56; n=98; p<0.0001). The cutoff level of edema measured by portable ultrasound in non-obese pregnant women was 4.7 mm (sensitivity 83.9%, specificity 66.7%) and was 7.5 mm in obese pregnant women. Obese pregnant women with edema had a significantly increased leg skin thickness compared with non-obese pregnant women with edema (11.3±1.3 mm vs. 5.7±0.2 mm) (p<0.0001). CONCLUSIONS Portable ultrasonography is a reliable method of quantitatively measuring skin thickness of the lower leg in edema associated with pregnancy. The thickness of the skin in obese pregnant women with edema can be expected to be significantly increased compared with non-obese pregnant women with edema.

Avian Ganglioneuritis in Clinical Practice

Avian ganglioneuritis (AG) comprises one of the most intricate pathologies in avian medicine and is researched worldwide. Avian bornavirus (ABV) has been shown to be a causative agent of proventricular dilatation disease in birds. The avian Bornaviridae represent a genetically diverse group of viruses that are widely distributed in captive and wild populations around the world. ABV and other infective agents are implicated as a cause of the autoimmune pathology that leads to AG, similar to human Guillain Barrè syndrome. Management of affected birds is beneficial and currently centered at reducing neurologic inflammation, managing secondary complications, and providing nutritional support.

Association between estimated glomerular filtration rate and outcomes in patients with diabetic foot ulcers: a 3-year follow-up study

OBJECTIVE

End-stage renal disease and dialysis have been proven to be associated with poor prognoses in diabetic foot ulcers (DFUs). However, it has rarely been reported whether and to what extent milder renal insufficiency affects the prognosis. The purpose of this study was to investigate the categorized impact of estimated glomerular filtration (eGFR) on the outcomes of patients with DFU.

DESIGN AND METHODS

Three hundred and sixty-six DFU patients hospitalized in a Chinese tertiary hospital were recruited and classified into 4 groups according to the eGFRs as follows: normal (≥90), mildly reduced (60-89), moderately reduced (30-59), and severely reduced (<30). These patients were followed-up for an average of 37 months to observe the outcomes, including ulcer healing, amputation, ulcer recurrence, cardiac or cerebrovascular events and death. The associations between eGFR and the outcomes were analysed by Cox proportional-hazards models.

RESULTS

Compared to patients with normal eGFR, patients with moderately reduced eGFR had higher risk of healing failure (hazard ratio (HR) = 2.08, 95% confidence interval (CI): 1.13-3.82), cardiac events (HR = 5.25, 95% CI: 2.17-12.89) and death (HR = 3.54, 95% CI: 1.36-9.20). Severely reduced eGFR was associated with higher incidence of healing failure (HR = 2.84, 95% CI: 1.25-6.49) and death (HR = 4.45, 95% CI: 1.23-16.07). The impact of eGFR on ulcer recurrence and cerebrovascular events was not observed in all groups.

CONCLUSIONS

Moderately and severely reduced eGFR in patients with DFU were independent predictors for poor prognoses of both the limbs and the patients.

Assessment of Conjunctival Microvascular Hemodynamics in Stages of Diabetic Microvasculopathy

Diabetes impairs the microcirculation and function of various vital tissues throughout the body. The conjunctival microcirculation can be non-invasively imaged and thus enables assessment of microvascular hemodynamics. In this study, alterations in conjunctival microvascular hemodynamics were quantitatively assessed at stages of increasing diabetic microvasculopathy based on diabetic retinopathy (DR). Subjects were categorized into non-diabetic control (C, N = 34), no clinically visible DR (NDR, N = 47), non-proliferative DR (NPDR, N = 45), and proliferative DR (PDR, N = 35). Conjunctival hemodynamic descriptors, namely vessel diameter (D), blood velocity (V), blood flow (Q), wall shear rate (WSR), and wall shear stress (WSS) were measured in arterioles and venules, and compared between DR and C subjects using generalized linear mixed models. In arterioles, V, WSR, and WSS were lower in NDR (P ≤ 0.01). V was lower in NDR than NPDR and PDR subjects (P ≤ 0.02). In venules, D was higher in NDR and NPDR (P ≤ 0.03), while V was lower in PDR (P = 0.04). Venular V and Q were higher in NPDR than PDR subjects (P ≤ 0.04). WSR and WSS were lower in all stages of DR (P ≤ 0.05), suggestive of the potential of WSS as a marker of diabetic microvasculopathy. Quantitative assessment of conjunctival hemodynamics can potentially be useful for evaluation of diabetic microvasculopathy.

Effects of pulsed electromagnetic fields on peripheral blood circulation in people with diabetes: A randomized controlled trial

Cutaneous blood flow provides nourishment that plays an essential role in maintaining skin health. We examined the effects of pulsed electromagnetic fields (PEMFs) on cutaneous circulation of dorsal feet. Twenty-two patients with diabetes mellitus (DM) and 21 healthy control subjects were randomly allocated to receive either PEMFs or sham PEMFs (0.5 mT, 12 Hz, 30 min). Blood flow velocity and diameter of the small vein were examined by using ultrasound biomicroscopy; also, microcirculation at skin over the base of the 1st metatarsal bone (Flux1) and distal 1st phalange (Flux2) was measured by laser Doppler flowmetry before and after intervention. Results indicated that PEMFs produced significantly greater changes in blood flow velocity of the smallest observable vein than did sham PEMFs (both P < 0.05) in both types of subjects. However, no significant difference was found in changes of vein diameter, nor in Flux1 and Flux2, between PEMFs and sham PEMFs groups in subjects with or without DM. We hypothesized that PEMFs would increase blood flow velocity of the smallest observable vein in people with or without DM. Bioelectromagnetics. 37:290-297, 2016. © 2016 Wiley Periodicals, Inc.

An early diagnostic tool for diabetic peripheral neuropathy in rats

The skin’s rewarming rate of diabetic patients is used as a diagnostic tool for early diagnosis of diabetic neuropathy. At present, the relationship between microvascular changes in the skin and diabetic neuropathy is unclear in streptozotocin (STZ) diabetic rats. The aim of this study was to investigate whether the skin rewarming rate in diabetic rats is related to microvascular changes and whether this is accompanied by changes observed in classical diagnostic methods for diabetic peripheral neuropathy. Computer-assisted infrared thermography was used to assess the rewarming rate after cold exposure on the plantar skin of STZ diabetic rats’ hind paws. Peripheral neuropathy was determined by the density of intra-epidermal nerve fibers (IENFs), mechanical sensitivity, and electrophysiological recordings. Data were obtained in diabetic rats at four, six, and eight weeks after the induction of diabetes and in controls. Four weeks after the induction of diabetes, a delayed rewarming rate, decreased skin blood flow and decreased density of IENFs were observed. However, the mechanical hyposensitivity and decreased motor nerve conduction velocity (MNCV) developed 6 and 8 weeks after the induction of diabetes. Our study shows that the skin rewarming rate is related to microvascular changes in diabetic rats. Moreover, the skin rewarming rate is a non-invasive method that provides more information for an earlier diagnosis of peripheral neuropathy than the classical monofilament test and MNCV in STZ induced diabetic rats.

Transcutaneous oxygen pressure (TcPO₂): a novel diagnostic tool for peripheral neuropathy in type 2 diabetes patients

AIMS

The assessment of transcutaneous oxygen pressure (TcPO2) may serve as a non-invasive and lower-cost alternative to nerve conduction studies (NCSs) for the diagnosis of diabetic peripheral neuropathy (DPN). The aim of this study was to determine whether the measurement of TcPO2 is useful for evaluating DPN.

METHODS

We performed a cross-sectional study of 381 consecutive hospitalized diabetic patients classified by clinical examination and NCS as having DPN. Anthropometric and metabolic parameters were assessed. The TcPO2 examination was performed in both supine and sitting positions.

RESULTS

Three hundred and one patients had DPN. The TcPO2 in both the supine and sitting positions was highest in the Non-DPN group and lower in the confirmed DPN group than the other three groups (p<0.001). The Non-DPN group had the lowest sitting-supine position difference in TcPO2 among the groups (p<0.001). The risk factors strongly associated with DPN included sitting-supine position difference in TcPO2 (OR=4.971, p<0.001), diabetic retinopathy (DR) (odds ratio [OR]=3.794, p=0.002), and HbA1c (OR=1.534, p=0.033). The area under the curve (AUC) of the sitting-supine position difference in TcPO2 was 0.722 and revealed an optimal cut-off point for the identification of DPN (19.5 mmHg) that had a sensitivity of 0.611 and a specificity of 0.738 based on AUC analysis.

CONCLUSIONS

This large study of diabetic patients confirms that the sitting-supine position difference in TcPO2 is higher in DPN patients than control subjects, indicating that TcPO2 examination is a promising valuable diagnostic tool for DPN.

Skin tissue water assessed via tissue dielectric constant measurements in persons with and without diabetes mellitus

BACKGROUND

Skin changes in diabetes mellitus (DM) include possible increases in foot skin water content as interpreted from altered echogenicity in high-frequency ultrasound images. The present goal was to investigate the possibility of undetected increased local skin water in persons with DM using a handheld portable rapid measuring device that measures the tissue dielectric constant (TDC) as an indicator of skin tissue water.

SUBJECTS AND METHODS

TDC measurements were done bilaterally on 18 persons with DM and 18 persons without DM (NODM) at foot dorsum and anterior forearm to tissue depths of 0.5, 1.5, and 2.5 mm. DM duration was 11.1 ± 10.9 years. Age, body mass index, and blood pressures were not significantly different between groups.

RESULTS

NODM and DM TDC values decreased with increasing depth at forearm but were depth independent at foot dorsum. All DM foot TDC values were significantly (P<0.05) greater than for NODM, with foot TDC values at 2.5 mm depth being 14.8% greater than in NODM. DM forearm TDC values were not significantly greater than NODM.

CONCLUSIONS

A technology that characterizes local skin water in a rapid and noninvasive way has been used for the first time in persons with DM. The greater TDC value at the foot dorsum of the DM group is consistent with the presence of previously unrecognized increased fluid content. This suggests that there may be benefit utilizing this measurement method as a way to screen for early changes in foot skin features that may tend to cause DM-related edema.

Effect of viscoelastic properties of plantar soft tissues on plantar pressures at the first metatarsal head in diabetics with peripheral neuropathy

Diabetic foot ulcers are one of the most serious complications associated with diabetes mellitus. Current research studies have demonstrated that biomechanical alterations of the diabetic foot contribute to the development of foot ulcers. However, the changes of soft tissue biomechanical properties associated with diabetes and its influences on the development of diabetic foot ulcers have not been investigated. The purpose of this study was to investigate the effect of diabetes on the biomechanical properties of plantar soft tissues and the relationship between biomechanical properties and plantar pressure distributions. We used the ultrasound indentation tests to measure force-deformation relationships of plantar soft tissues and calculate the effective Young's modulus and quasi-linear viscoelastic parameters to quantify biomechanical properties of plantar soft tissues. We also measured plantar pressures to calculate peak plantar pressure and plantar pressure gradient. Our results showed that diabetics had a significantly greater effective Young's modulus and initial modulus of quasi-linear viscoelasticity compared to non-diabetics. The plantar pressure gradient and biomechanical properties were significantly correlated. Our findings indicate that diabetes is linked to an increase in viscoelasticity of plantar soft tissues that may contribute to a higher peak plantar pressure and plantar pressure gradient in the diabetic foot.