Association between "diabetic thick skin syndrome" and neurological disorders in diabetes mellitus

Selection of Noninvasive Features in Wrist-Based Wearable Sensors to Predict Blood Glucose Concentrations Using Machine Learning Algorithms

Glucose monitoring technologies allow users to monitor glycemic fluctuations (e.g., blood glucose levels). This is particularly important for individuals who have diabetes mellitus (DM). Traditional self-monitoring blood glucose (SMBG) devices require the user to prick their finger and extract a blood drop to measure the blood glucose based on chemical reactions with the blood. Unlike traditional glucometer devices, noninvasive continuous glucose monitoring (NICGM) devices aim to solve these issues by consistently monitoring users' blood glucose levels (BGLs) without invasively acquiring a sample. In this work, we investigated the feasibility of a novel approach to NICGM using multiple off-the-shelf wearable sensors and learning-based models (i.e., machine learning) to predict blood glucose. Two datasets were used for this study: (1) the OhioT1DM dataset, provided by the Ohio University; and (2) the UofM dataset, created by our research team. The UofM dataset consists of fourteen features provided by six sensors for studying possible relationships between glucose and noninvasive biometric measurements. Both datasets are passed through a machine learning (ML) pipeline that tests linear and nonlinear models to predict BGLs from the set of noninvasive features. The results of this pilot study show that the combination of fourteen noninvasive biometric measurements with ML algorithms could lead to accurate BGL predictions within the clinical range; however, a larger dataset is required to make conclusions about the feasibility of this approach.

Cutaneous Manifestations of Diabetes

Diabetes mellitus is a significant worldwide health concern and cutaneous manifestations are common. This review describes characteristic skin findings of diabetes, general skin findings related to diabetes, and findings related to diabetes treatment with a focus on clinical presentation, diagnosis, pathophysiology, epidemiology, and treatment. As the prevalence of diabetes continues to rise, cutaneous manifestations of diabetes mellitus likely will be encountered more frequently by physicians in all disciplines including dermatologists and primary care physicians. Accordingly, knowledge regarding the prevention, diagnosis, and management of cutaneous manifestations is an important aspect in the care of patients with diabetes.

Is the C677T polymorphism in methylenetetrahydrofolate reductase gene or plasma homocysteine a risk factor for diabetic peripheral neuropathy in Chinese individuals?

The present study enrolled 251 diabetic patients, including 101 with neuropathy and 150 without neuropathy. Of the 150 patients, 100 had no complications, such as retinopathy, nephropathy, or neuropathy. Polymerase chain reaction-restriction fragment length polymorphism analysis was used to identify methylenetetrahydrofolate reductase gene variants. Plasma homocysteine levels were also measured. Homocysteine levels and the frequency of hyperhomocysteinemia were significantly higher in patients with diabetic peripheral neuropathy compared with diabetic patients without neuropathy (P < 0.05). In logistic regression analysis with neuropathy as the dependent variable, the frequency of C677T in methylenetetrahydrofolate reductase was significantly higher in patients with diabetic peripheral neuropathy compared with patients without diabetic complications. Homocysteine levels were significantly higher in patients with diabetic peripheral neuropathy carrying the 677T allele and low folic acid levels. In conclusion, hyperhomocysteinemia is an independent risk factor for diabetic neuropathy in Chinese patients with diabetes. The C677T polymorphism in methylenetetrahydrofolate reductase and low folic acid levels may be risk factors for diabetic peripheral neuropathy in Chinese patients with diabetes.

Dermatologic manifestation of diabetes

With the rising incidence of diabetes mellitus (DM) in the US, it is of paramount importance that practitioners understand the complications of DM and how best to manage them. Diabetes affects every organ system and the skin is no exception. There are numerous cutaneous manifestations of DM that have similar etiologies and result from the same pathologic mechanisms as the internal complications of this disease state. In addition, skin manifestations may precede the diagnosis of diabetes. The present article reviews both the common and less common cutaneous manifestations of DM, including presenting lesions, pathogenesis, and management.

Epidermal thickness and biomechanical properties of plantar tissues in diabetic foot

Diabetic foot is a common complication for people with diabetes but it is unclear whether the change is initiated from the skin surface or underneath plantar tissues. This study compared the thickness of epidermis and the thickness and stiffness of the total plantar soft tissue among people with diabetes with or without complications. Seventy-two people with diabetes, including 22 people with neuropathies, 16 foot ulcerations, 34 pure diabetics without complications and 40 healthy controls participated in the study. The thickness of the epidermal layer of the plantar skin was examined using high-frequency ultrasonography; the thickness and stiffness of the total plantar soft tissue were measured by using tissue ultrasound palpation system at the big toe, the first, third and fifth metatarsal heads; and the heel pad. Compared with the control group, the average epidermal thickness of plantar skin was reduced by 15% in people with diabetic foot ulceration and 9% in people with neuropathy, but was increased by 6% in pure diabetics. There was an 8% increase in total thickness of plantar soft tissue in the 3 diabetic groups at all testing sites (all p < 0.05), except the first metatarsal head. The stiffness of plantar soft tissue was increased in all diabetic groups at all testing sites compared with the control (all p < 0.05). The epidermal plantar skin becomes thinner and plantar soft tissues stiffen in people with diabetes, particularly in persons who have neuropathy or ulceration, which increases the risk of tissue breakdown and ulceration formation.

Statin therapy and diabetic skin

PURPOSE

Statins are widely used drugs for reducing cholesterol levels. The aim of this study was to observe the effects of statin therapy on skin histopathology in both normal and diabetic mice.

METHODS

45 Swiss albino mice were studied in 4 sub-groups: control, statin-treated control, diabetic, and statin-treated diabetic. The first group was diabetic-induced with 250 mg/kg of streptozosin administered intravenously. The second group served as the control. Four weeks after streptozosin injection, both diabetic and control groups were divided into 2 sub-groups and 1 mg/kg/d simvastatin was injected for 14 d intraperitoneally to form the statin-treated control and statin-treated diabetic groups. The remaining 2 groups formed the untreated control and untreated diabetic groups. Histopathological examination of the skin was made with haematoxylin eosin staining under a light microscope.

RESULTS

There was no apparent difference between the groups in epidermal thickness, proliferative activity, dermal thickness and composition. Cystic dilatations in the infundibulum of hair follicles with distorted and smaller sebaceous glands were seen in the statin-treated control, diabetic, and statin-treated diabetic groups.

CONCLUSION

We conclude that there is altered lipid synthesis in the sebaceous glands in both diabetic and statin-treated groups.

Measurement of skin elasticity on the foot

BACKGROUND/PURPOSE

The Cutometer 580 MPA is a device that is designed to measure the viscoelastic properties of skin in response to the application of negative pressure. The aim of this study was to test the Cutometer 580 MPA for the repeatable, quantitative measurement of the specific indices of elasticity of pedal skin. The device was used to measure and compare these indices at weight-bearing and non-weight-bearing skin sites on the foot.

METHODS

The relationship between the pressure application and skin displacement was determined. The inter- and intra-tester repeatability was tested. These series of experiments were conducted on 20 individuals. Data were then collected from a group of 87 healthy people for the measurement of elasticity, viscoelasticity and plasticity on several sites on the foot. The possible influences of physiological variables such as age and sex on the indices of elasticity were analysed.

RESULTS

The Hookian elastic behaviour of the skin was confirmed. The pressure application did not remain constant during the collection of displacement data, resulting in an error in these readings of between 1.71% and 3.73%. Intra-tester and variability was minimal (CV<7%). The elasticity, viscoelasticity and plasticity indices were significantly greater (P<0.001) in dorsal skin compared with skin from medial longitudinal arch (MLA) and plantar aspect of the third metatarsophalangeal joint (PMA) sites. There was a negative correlation between age and elasticity on the dorsum and MLA skin sites (r=-0.216 and -0.261, respectively). Female skin exhibited greater plasticity than male skin on all three sites on the foot (P<0.05).

CONCLUSION

Under well-controlled conditions, the Cutometer 580 MPA has the ability to measure accurately the viscoelastic properties of pedal skin. Such non-invasive measurements may be useful for the evaluation of changes in the skin in response to therapeutic interventions and for monitoring the progression of dermatological conditions associated with the foot.

Diabetes mellitus

Dermatologic problems are common in diabetes, with approximately 30% of patients experiencing some cutaneous involvement during the course of their illness. Skin manifestations generally appear during the course of the disease in patients known to have diabetes, but they may also be the first presenting sign of diabetes or even precede the diagnosis by many years. The skin involvement can be autoimmune in nature, such as acanthosis nigricans, necrobiosis lipoidica, diabetic dermopathy, scleredema, and granuloma annulare, or infectious in the form of erythrasma, necrotizing fasciitis, and mucormycosis. Pharmacologic management of diabetes, in addition, can also result in skin changes, such as lipoatrophy and lipohypertrophy, at the site of injection of insulin, and oral antidiabetic agents can cause multiple skin reactions as adverse effects. The management of these cutaneous manifestations is tailored according to the underlying pathophysiology, but a tight control of blood glucose is a prerequisite in all management strategies.

Noise contribution to the correlation between temperature-induced localized reflectance of diabetic skin and blood glucose

We used the effect of temperature on the localized reflectance of human skin to assess the role of noise sources on the correlation between temperature-induced fractional change in optical density of human skin (DeltaOD(T)) and blood glucose concentration [BG]. Two temperature-controlled optical probes at 30 degrees C contacted the skin, one was then cooled by -10 degrees C; the other was heated by +10 degrees C. DeltaOD(T) upon cooling or heating was correlated with capillary [BG] of diabetic volunteers over a period of three days. Calibration models in the first two days were used to predict [BG] in the third day. We examined the conditions where the correlation coefficient (R2) for predicting [BG] in a third day ranked higher than R2 values resulting from fitting permutations of randomized [BG] to the same DeltaOD(T) values. It was possible to establish a four-term linear regression correlation between DeltaOD(T) upon cooling and [BG] with a correlation coefficient higher than that of an established noise threshold in diabetic patients that were mostly females with less than 20 years of diabetes duration. The ability to predict [BG] values with a correlation coefficient above biological and body-interface noise varied between the cases of cooling and heating.

Impact of environmental temperature on skin thickness and microvascular blood flow in subjects with and without diabetes

BACKGROUND

Glucose measurement from different skin areas might be influenced by changes in skin texture due to several environmental confounders. Our study was performed to investigate the effect of changes in ambient temperature on skin thickness and microvascular skin blood flow in subjects with and without diabetes at the lower forearm.

METHODS

Thirteen subjects with diabetes and seven without diabetes participated in the study. The investigations were performed in a temperature- and humidity-controlled climatic chamber (EMPA, St. Gallen, Switzerland). Starting at 25 degrees C, the environmental temperature was changed in 4 degrees C steps every 40 min. Skin thickness was measured by an ultrasonic reflection technique, and microcirculation was measured by laser Doppler fluxmetry at the lower forearm. Study participants underwent the entire procedure on up to four separate study trials.

RESULTS

Our study revealed a significantly reduced skin thickness (P<0.05) and microvascular blood flow (P<0.05) in patients with diabetes mellitus compared with controls without diabetes during the entire investigation. During declining ambient temperature a significant reduction in skin thickness (with diabetes, -0.09+/-0.13 mm; without diabetes, -0.06+/-0.11 mm; P<0.05) and microvascular blood flow (with diabetes, -41+/-49 arbitrary units; without diabetes, -46+/-51 arbitrary units; P<0.05) could be observed in both groups without significant differences between the two.

CONCLUSIONS

Although skin thickness and microvascular skin blood flow at the lower forearm were found to be reduced in patients with diabetes compared with controls without diabetes, both groups revealed comparable dynamics in skin thickness and microvascular blood flow during changes in environmental temperature.

Characteristics of the epidermis and stratum corneum of hairless mice with experimentally induced diabetes mellitus

Diabetes mellitus induces many pathophysiologic changes in the skin. Even so, dermatologists still lack an animal model of diabetes that enables the direct evaluation of the various functional properties of the skin. Our group induced two types of an experimental type 1 diabetes model in hairless mice by administering either streptozotocin or alloxan, in order to examine the properties of the stratum corneum and epidermis of these animals. The plasma glucose concentrations of the mice at 3 wk after their i.v. injection were significantly higher than those of control mice (streptozotocin, 3.2-fold; alloxan, 3.7-fold). The stratum corneum water content was significantly reduced in both types of diabetic mice, whereas the transepidermal water loss remained unchanged. The amino acid content with normal epidermal profilaggrin processing was either normal or elevated in the stratum corneum of the streptozotocin-treated mice. In contrast, the stratum corneum triglyceride content in the streptozotocin-treated mice was significantly lower than the control level, even though the levels of ceramides, cholesterols, and fatty acids in the stratum corneum were all higher than the control levels. The streptozotocin-treated group also exhibited decreases in basal cell proliferation and epidermal DNA content linked with an increase in the number of corneocyte layers in the stratum corneum, suggesting that the rates of epidermal and stratum corneum turnover were slower in the streptozotocin-treated animals than in the normal controls. In contrast, there were no remarkable changes in any of the epidermal differentiation marker proteins examined. This finding in diabetic mice, namely, reduction in both the epidermal proliferation and stratum corneum water content without any accompanying impairment in the stratum corneum barrier function, is similar to that found in aged human skin. Our new animal model of diabetes will be useful for the study of diabetic dermopathy as well as the mechanisms of stratum corneum moisturization.

Ultrasonography of plantar soft tissues thickness in young people with diabetes

AIMS

The aims of this study were to examine soft tissue changes in the skin and plantar aponeurosis of young people with Type 1 diabetes mellitus (T1DM) and to evaluate any relationship between any soft tissue changes, arch length, limited joint mobility (LJM) and plantar pressure.

METHODS

The thickness of the skin on the plantar surface of the foot and plantar aponeurosis were examined using ultrasound in 216 young people with diabetes and 57 controls. Foot length, arch length, joint mobility, peak pressure and pressure time integrals were evaluated.

RESULTS

Skin was not significantly thicker in the diabetic subjects. The plantar aponeurosis was significantly thicker in the diabetic subjects and was associated with foot size, male gender and subtalar joint (ST) LJM (P < 0.01). Males were nearly three times more likely to have thickened plantar aponeurosis.

CONCLUSION

Soft tissue thickening in young people with T1DM affects the deeper structures on the plantar surface of the foot rather than the skin. Thickening of the plantar aponeurosis was associated with LJM at the ST joint and male gender, but was not associated with plantar pressure or arch height changes. Plantar aponeurosis thickening does not appear to alter foot mechanics in young people with T1DM.

Cutaneous manifestations of diabetes mellitus

Diabetes is a common disease with many cutaneous manifestations encountered by dermatologists. Diabetes and the skin may be linked by association (e.g., necrobiosis lipoidica); infection; diabetic complication (e.g., neuropathic ulcer); or treatment reaction. Review of recent studies and reports focuses on pathogenesis and treatment of these many diabetic cutaneous changes.

Relation between homocysteinaemia and diabetic neuropathy in patients with Type 2 diabetes mellitus

AIMS

Limited data are available on determinants of diabetic neuropathy as its pathogenesis is multifactorial. Since homocysteine exhibits toxic effects on vascular endothelial cells, the association between homocysteine and the prevalence of neuropathy in Type 2 diabetes mellitus was investigated.

METHODS

A total of 65 Type 2 diabetic patients were consecutively enrolled into the study. Neuropathy was diagnosed according to clinical symptoms, clinical examination, electrophysiological sensory testing and autonomic function testing. With regard to homocysteine-related parameters, plasma homocysteine, folate, vitamin B12, vitamin B6 and renal function (creatinine, ceratinine clearance, cystatin C) were measured, and the C677T polymorphism of the methylenetetrahydrofolate reductase gene was determined.

RESULTS

Forty-three of the Type 2 diabetic patients were classified as suffering from neuropathy. Both patient groups were comparable with regard to demographic data, blood pressure, glucose metabolism, renal function and homocysteine-related vitamins. In contrast, homocysteine levels (P = 0.04) and the frequency of hyperhomocysteinemia (>or= 15 micromol/l) (P = 0.01) were significantly increased in neuropathic patients. In a logistic regression model with neuropathy as dependent variable, homocysteine (adjusted for creatinine, homocysteine-related vitamins, HbA1c and duration of diabetes) was the only significant variable associated with the prevalence of neuropathy (odds ratio for homocysteine per 5 micromol/l increase: 2.60 (95% confidence interval 1.07-6.33)).

CONCLUSION

The data indicate that homocysteine is independently associated with the prevalence of diabetic neuropathy in a collective of Type 2 diabetic patients. A larger, prospective study would be desirable to clarify the role of homocysteine in the pathogenesis of diabetic neuropathy.

Subclinical skin stiffening in adults suffering from type 1 diabetes mellitus. A comparison with Raynaud's syndrome

Acral skin of patients suffering from either type 1 diabetes mellitus or Raynaud's syndrome may become stiffer than normal. Such changes have not yet been thoroughly assessed using biometrological methods. The purpose of this study was to compare the mechanical properties of skin in these two conditions. Subclinical alterations were looked for on the back of the hands. We used an in vivo suction device equipped with two probes measuring skin extensibility and elasticity of the superficial and deep layers of the skin, respectively. A total of 58 middle aged adults with type 1 diabetes, 26 patients suffering from Raynaud's syndrome and 50 sex- and age-matched healthy volunteers participated in the study. There is evidence that both diseases affect the biomechanical properties of the dermis and of the underlying tissues. The dual changes are apparently opposite, corresponding to a superficial dermal laxity while the deep dermo-hypodermal tissues show some stiffening. From a biomechanical point of view, type 1 diabetes aggravates skin ageing and is also responsible for a subclinical skin stiffening in many patients. Raynaud's syndrome shows similar changes although the skin ageing effect is less prominent and the skin stiffening more frequent.

Comparison of the microvascular response to transcutaneous electrical nerve stimulation and postocclusive ischemia in the diabetic foot

Neurogenic inflammation, mediated by unmyelinated C-nerve fibers, is part of the acute neurovascular response to injury. Laser doppler flowmetry was used to measure the flare response to transcutaneous electrical nerve stimulation (TENS) and to compare this axon reflex vasodilatation with postischemic hyperemia in the skin of the foot in diabetic and nondiabetic subjects. Twenty-one control subjects and 57 diabetic patients (25 type I; 32 type II; 14 without complications; 14 with neuropathy and without retinopathy; 8 with retinopathy and without neuropathy; 21 with neuropathy and retinopathy) were enrolled in the study. Following TENS, an increase in skin blood flow was found at the dorsum of the foot without any significant difference between the different groups. Compared to the control group, axon reflex vasodilatation was significantly reduced in the group of patients with diabetic neuropathy and in the group of patients with diabetic neuropathy and retinopathy at the pulp of the hallux (61 +/- 15 versus -6 +/- 16; versus 23 +/- 5; p < 0.05, respectively). All investigated groups exhibited a significant increase in skin blood flow after arterial occlusion without any significant difference between the groups. A good association was observed between postocclusive and TENS-induced hyperemia at the dorsum of the foot (r = 0.39; p = 0.0002), but only a weak association was found at the pulp of the hallux (r = 0.24; p = 0.03). TENS-induced hyperemia was associated with a diminished sweat response (p = 0.03), but not with pathological cardiovascular function tests (p = 0.07). Electrical axon reflex vasodilatation is diminished in diabetic patients suffering from peripheral autonomic C-fiber injury, especially in skin rich in thermoregulatory blood flow. The diminished neurovascular response is independent of vascular alterations in diabetes mellitus.

Peripheral osteopenia in adult patients with insulin-dependent diabetes mellitus

Alterations in bone metabolism in diabetes mellitus is a topic of special interest. Bone blood flow is increased in the distal limb of diabetic patients, which is believed to increase osteoclastic activity. We measure bone mineral density using dual-photon absorptiometry in the distal lower limb, the femoral neck, and the lumbar spine in 41 IDDM patients and in 30 control persons. In the diabetic group there was a 10% reduction of bone mineral density in the femoral neck (p < 0.01) and a 12% reduction in the distal limb (p < 0.001) compared with the control group. No significant difference was found in the lumbar spine (p = 0.22). Our data yield incidence for peripheral osteopenia in IDDM-patients, independent of any systemic bone disease such as osteoporosis. A link between decreased bone mineral density and diabetic neuropathy has been observed for the femoral neck (p < 0.001), but not for the distal limb or axial skeleton. Whether there is a common aetiological link or a casual connection between diabetic neuropathy and bone mineral density has still to be determined.