Effect of Exercise Volume on Plantar Microcirculation and Tissue Hardness in People With Type 2 Diabetes

Plantar Tissue Characteristics in People With Diabetes With and Without Peripheral Neuropathy: A Novel Explanatory Model for DPN Risk Assessment

OBJECTIVES

Diabetic peripheral neuropathy (DPN) may affect the biomechanical properties and morphology of the plantar tissue. This study aimed to compare plantar stiffness and thickness in individuals with diabetes with and without DPN and develop a novel explanatory model for DPN risk assessment by integrating these measures with clinical parameters.

MATERIALS & METHODS

Thirty-two healthy controls and 84 people with diabetes (41 with DPN and 43 without DPN) were included. Shear wave elastography evaluated plantar thickness and stiffness at the heel, hallux, and first and fifth metatarsal heads (1st MTH, 5th MTH). An integrated thickness or stiffness index was generated at multiple locations by principal component analysis (PCA).

RESULTS

People with DPN showed a significant increase in plantar thickness (heel, 1st MTH) (p < 0.001) and stiffness (all tested locations) compared to healthy controls (p < 0.05). Moreover, plantar thickness at 1st MTH, plantar stiffness at 5th MTH, and integrated stiffness index generated by PCA were significantly higher in DPN than in the non-DPN group (p < 0.05). A DPN explanatory model was developed using multivariate logistic regression, incorporating the integrated plantar stiffness index, diabetes duration, and gender. The model showed high discriminative ability (AUROC: 97.7%), with an optimal cutoff of 0.56 yielding 92.7% sensitivity and 95.3% specificity.

CONCLUSION

The integrated plantar stiffness index, combined with gender and diabetes duration, offers a novel approach for DPN, providing a noninvasive tool for DPN risk assessment.

Diagnosis, Pathophysiology and Management of Microvascular Dysfunction in Diabetes Mellitus

Microcirculation is an essential system that regulates oxygen and nutrients to cells and tissues in response to various environmental stimuli and pathophysiological conditions. Diabetes mellitus can cause microvascular complications including nephropathy, neuropathy, and retinopathy. The pathogenesis of microvascular dysfunction in diabetes is associated with hyperglycemia and the result of an interplay of various factors. Research studies have demonstrated that functional microvascular dysfunction appears much earlier than structural alterations in vasculature in diabetes. This finding of the progression from microvascular dysfunction to macrovascular disease establishes a foundation for the screening and early diagnosis of diabetes by assessing the microvascular function. This comprehensive review discusses technologies (laser Doppler, transcutaneous oximetry, infrared thermography and near-infrared spectroscopy) with computational methods (linear (time and frequency domains), nonlinear and machine learning approaches) for diagnosing microvascular dysfunction in diabetes. Pathophysiological changes of microvascular dysfunction leading to impaired vasomotion and blood flow oscillations in diabetes are reviewed. Recent findings in managing microvascular dysfunction using lifestyle modifications and force-based modulations are evaluated. A consensus endorsed by the American Diabetes Association has been reached that an effective exercise program would greatly slow down the progression of microvascular dysfunction and its impact on diabetic foot ulcers, muscle fatigue and weakness and peripheral neuropathy. However, it is imperative to determine the dose-response relationship of exercise and microvascular responses in patients with diabetes. Research studies have demonstrated that local vibration and whole-body vibration can improve microcirculation in various pathological conditions, including diabetes. Due to the complex nature of microvascular regulation, various computational methods have been developed to shed light on the influence of diabetes on microvascular dysfunction. This comprehensive review will contribute to the diagnosis and management of microvascular dysfunction in diabetes.

Evaluation of enhanced external counterpulsation for diabetic foot based on a patient-specific 0D-1D cardiovascular system model

BACKGROUND AND OBJECTIVE

Diabetic foot (DF) complications often lead to severe vascular issues. This study investigated the effectiveness of enhanced external counterpulsation (EECP) and its derived innovative compression strategies in addressing poor perfusion in DF. Although developing non-invasive and efficient treatment methods for DF is critical, the hemodynamic alterations during EECP remain underexplored despite promising outcomes in microcirculation. This research sought to address this gap by developing a patient-specific 0D-1D model based on clinical ultrasound data to identify potentially superior compression strategies that could substantially enhance blood flow in patients with DF complications.

METHODS

Data were gathered from 10 patients with DF utilizing ultrasound for blood flow rate and computed tomography angiography (CTA) to identify lower limb conditions. Clinical measurements during standard EECP, with varying cuff pressures, facilitated the creation of a patient-specific 0D-1D model through a two-step parameter estimation process. The accuracy of this model was verified via comparison with the clinical measurements. Four compression strategies were proposed and rigorously evaluated using this model: EECP-Simp-I (removing hip cuffs), EECP-Simp-II (further removing the cuffs around the lower leg), EECP-Impr-I (removing all cuffs around the affected side), and EECP-Impr-II (building a loop circulation from the healthy side to the affected side).

RESULTS

The predicted results under the rest and standard EECP states were generally closely aligned with clinical measurements. The patient-specific 0D-1D model demonstrated that EECP-Simp-I and EECP-Impr-I contributed similar enhancement to perfusion in the dorsal artery (DA) and were comparable to standard EECP, while EECP-Simp-II had the least effect and EECP-Impr-II displayed the most significant enhancement. Pressure at the aortic root (AO) remained consistent across strategies.

CONCLUSIONS

EECP-Simp-I is recommended for patients with DF, emphasizing device simplification. However, EECP-Simp-II is discouraged as it significantly diminished blood perfusion in this study, except in cases of limb fragility. EECP-Impr-II showed superior enhancement of blood perfusion in DA to all other strategies but required a more complex EECP device. Despite increased AO pressure in all the proposed compression strategies, safety could be guaranteed as the pressue remained within a safe range.

Dynamic Microcirculation Characteristics of Plantar Skin Under Metatarsal Head of Human Foot in Response to Life-Like Pressure Stimulus

OBJECTIVE

Diabetic foot ulcer (DFU) is a severe complication with high mortality. High plantar pressure and poor microcirculation are considered main causes of DFU. The specific aims were to provide a novel technique for real-time measurement of plantar skin blood flow (SBF) under walking-like pressure stimulus and delineate the first plantar metatarsal head dynamic microcirculation characteristics because of life-like loading conditions in healthy individuals.

METHODS

Twenty young healthy participants (14 male and 6 female) were recruited. The baseline (i.e., unloaded) SBF of soft tissue under the first metatarsal head were measured using laser Doppler flowmetry (LDF). A custom-made machine was utilized to replicate daily walking pressure exertion for 5 min. The exerted plantar force was adjusted from 10 N (127.3 kPa) to 40 N (509.3 kPa) at an increase of 5 N (63.7 kPa). Real-time SBF was acquired using the LDF. After each pressure exertion, postload SBF was measured for comparative purposes. Statistical analysis was performed using the R software.

RESULTS

All levels of immediate-load and postload SBF increased significantly compared with baseline values. As the exerted load increased, the postload and immediate-load SBF tended to increase until the exerted load reached 35 N (445.6 kPa). However, in immediate-load data, the increasing trend tended to level off as the exerted pressure increased from 15 N (191.0 kPa) to 25 N (318.3 kPa). For postload and immediate-load SBF, they both peaked at 35 N (445.6 kPa). However, when the exerted force exceeds 35 N (445.6 kPa), both the immediate-load and postload SBF values started to decrease.

CONCLUSIONS

Our study offered a novel real-time plantar soft tissue microcirculation measurement technique under dynamic conditions. For the first metatarsal head of healthy people, 20 N (254.6 kPa)-plantar pressure has a fair microcirculation stimulus compared with higher pressure. There might be a pressure threshold at 35 N (445.6 kPa) for the first metatarsal head, and soft tissue microcirculation may decrease when local pressure exceeds it.

Prescribing Home Digital Thermometry Coupled with Activity Dosing and Optimized Offloading to Prolong Diabetic Foot Remission: A Case Report

People with a history of diabetic foot ulcers (DFUs) experience diminished health-related quality of life and are at a 40% annual risk of DFU recurrence. Due to a fear of DFU recurrence, people in DFU remission participate less in physical activity and moderate-intensity exercise when compared to people with diabetes who have not had wounds. There is novel evidence to suggest that too little activity during DFU remission contributes to only low magnitudes of repetitive tissue loading creating a higher susceptibility to skin trauma during inadvertent high-activity bouts. Conversely, a hasty return to too much activity could lead to rapid recurrence. There is now high-level evidence from multiple meta-analyses to indicate that home-based foot temperature monitoring, coupled with activity modification and daily inspection of the feet for impending signs of ulceration, could reduce the risk of ulcer recurrence by 50%. There is little evidence, however, to guide the decision-making regarding the appropriate quantity and frequency of physical activity during DFU remission and the acceptability from the patient perspective. This has resulted in limited uptake of this novel intervention in clinical practice. Earlier, we proposed that activity can be dosed for people in foot ulcer remission, just like insulin or medication is dosed. Here, we describe a patient-centered approach to implementing home foot temperature monitoring coupled with daily foot checks and dosage-based return to physical activity in a patient in DFU remission, including his perspective. We believe using such an approach could maximize ulcer-free days in remission, thereby improving quality of life.

A scientometrics analysis and visualisation of diabetic foot research from 1955 to 2022

Diabetic foot (DF) has become a serious health problem in modern society, and it has been a hotspot of research for a long time. However, little scientometric analysis has been carried out on DF. In the present study, we analysed 8633 literature reports on DF in the Web of Science Core Collection from database inception until April 23, 2022. VOSviewer (Centre for Science and Technology Studies at Leiden University, Leiden, the Netherlands) and CiteSpace (College of Computing and Informatics, Drexel University, Philadelphia, United States) were employed to address high-impact countries and institutions, journals, references, research hotspots, and key research fields in DF research. Our analysis findings indicated that publications on DF have increased markedly since 2016 and were primarily published in the United States of America. The recent studies focus on the amniotic membrane, foot ulcers, osteomyelitis, and diabetic wound healing. The five keyword clusters, which included DF ulcer and wound healing therapies, management and guidelines, neuropathy and plantar pressure, amputation and ischemia, and DF infection and osteomyelitis, are helpful for enhancing prevention, standardising treatment, avoiding complications, and improving prognosis. These findings indicated a method for future therapies and research in DF.

Using a contralateral shoe lift to reduce gait deterioration during an offloading fast-walk setting in diabetic peripheral neuropathy: A comparative feasibility study

AIMS

Diabetic peripheral neuropathy (DPN) is a predictor of foot ulcers and leads to sedentary behaviour. This comparative study evaluated gait and feasibility of a 20-minute fast walk, at 40-60% of cardiopulmonary capacity, in individuals with DPN wearing an offloading boot and a contralateral shoe balancer.

METHODS

Gait parameters were measured with inertial sensors on 32 individuals (group with DPN [n = 16], group with diabetes but without DPN [n = 9], and a group without diabetes/DPN [n = 7]). Feasibility was assessed by feedback on perceived effort and adverse events. Gait outcomes were compared between groups with or without a shoe balancer using one-way ANOVAs.

RESULTS

The three groups were equivalent in terms of activity level and age and gender except for the body mass index. Both groups with diabetes exhibited minimal decreased gait speed (p > 0.005) and the DPN group exhibited increased double-support percentage (+4.6%, p = 0.01) while walking with an offloading boot and contralateral shoe balancer. The use of a contralateral shoe balancer reduced gait asymmetry. Lower physical activity level was associated with further gait deterioration in all groups. Few adverse events were reported, and 91% of participants reported that the proposed activity would be feasible daily.

CONCLUSIONS

The offloading boot deteriorated gait function, but a contralateral shoe balancer minimized its impact, especially in the context of physical activity in people with diabetes and DPN.

Diabetes as an Isolated Cause of Minor Lower Limb Amputations

Objectives

Amputation is a devastating but preventable complication of diabetes and peripheral arterial disease. The aim of the present study was to investigate whether diabetes mellitus is an important isolated cause of toe amputation.

Methods

A cross-sectional study was conducted involving the records of 108 patients with minor lower limb amputations and 80 with major lower limb amputations. Association between diabetes/chronic arterial insufficiency and level of amputation was tested. Statistical analysis was performed using Fisher's exact test.

Results

The prevalence of diabetes was 87.5% among patients submitted to minor amputations and 52.5% among those submitted to major amputations with or without chronic arterial disease. This difference was statistically significant (p<0.0001, Fisher's exact test). A total of 44.44% of the patients submitted to minor amputations had diabetes alone (no chronic arterial insufficiency), whereas only 14.81% of the patients submitted to major amputations did not have chronic arterial insufficiency. Thus, diabetes was significantly associated with minor lower limb amputations (p<0.0004, Fisher's exact test).

Conclusion

Based on the present findings, patients with diabetes are at greater risk of toe amputation compared to those with chronic arterial disease.