Histomorphological Evaluation of Diabetic and Non-Diabetic Plantar Soft Tissue

Abstract

Background Diabetic foot ulceration has a complex and multi-factorial etiology and can involve changes in the pathophysiology of the plantar soft tissue. In the current study, histomorphological analyses of diabetic and non-diabetic plantar tissue were performed. It was hypothesized that the diabetic tissue would have thicker skin (epidermis and dermis), less interdigitation between the dermis and epidermis, thicker elastic septa and decreased adipose cell size. Materials and Methods Two locations of the foot (the heel and the first metatarsal) were examined, both of which have been reported to be locations with a high incidence of ulceration. Stereological methods and quantitative morphological techniques were used to evaluate the skin thickness, interdigitation index, elastic septae thickness and adipocyte cell size. Results The diabetic donors had a greater body mass index (BMI) than the non-diabetic donors. The diabetic tissue had significantly thicker elastic septae and dermis. However, no significant difference was observed in the interdigitation index or adipocyte size. Conclusion These findings demonstrate that morphological changes can be evaluated histologically to give a better understanding of the pathological changes in the plantar soft tissue with diabetes. These evaluations can then be associated with biomechanical changes that occur in diabetes to provide new insight into how microstructural changes can alter macroscopic properties. Clinical Relevance An understanding of the histomorphological changes in the soft tissue in relationship to the location on the foot could help to explain the biomechanical changes that occur in diabetes and the subsequent increase in susceptibility to breakdown.

A stereologic study of the plantar fat pad in young and aged rats

“…The PFP is often involved in complications of the diabetic foot. Interestingly, it appears that the thickness of the elastic septa and the dermis are increased in diabetic PFP (Wang et al 2011). Thinning of the epidermis and stiffening of plantar soft tissues in diabetic PFP increase the risk of tissue breakdown and ulcer formation (Chao et al 2011).…”

“…This difference may well characterize FPU in aging, but it does not represent a reduction of the total number of adipocytes in the PFP. Studies on the diabetic PFP have found that the total number of adipocytes remains unchanged but the volume of adipocytes may or may not be reduced (Waldecker, 2001;Wang et al 2011). The FPU was featured as a collection of adipocyte clusters and a neurovascular bundle encased by an elastic septum.…”

“…A few clinical observations on PFP conflict with each other regarding the role of PFP in heel pain (Prichasuk, 1994;Waldecker & Lehr, 2009;Thomas et al 2010). The biochemistry and histomorphology of PFP in aging and diabetes have been studied using human cadaveric tissues (Jahss et al 1992;Waldecker & Lehr, 2009;Wang et al 2011), which are most relevant to PFP-related diseases but provide only sectional information of the pathology. Furthermore, these studies are limited by the inherent variations of human PFP tissues influenced by daily activities, body weight, genetics, genders, and other co-morbidities (Rchallis et al 2008).…”

Histomorphometric comparison after fixation with formaldehyde or glyoxal

“…These changes are particularly important with regard to ulceration of plantar foot tissues. One documented pathological change is increased thickness of the elastic septa (Jahss et al 1992, Buschmann et al 1995, Wang et al 2010). Although ideally all tissue used in a given study would be fixed in the same way, sometimes this is not possible.…”

The Effect of Prior Compression Tests on the Plantar Soft Tissue Compressive and Shear Properties

“…An understanding of the diseaseinduced tissue property changes that contribute to plantar ulceration requires first quantifying these changes under relevant plantar loading, i.e., compression and shear. Towards this goal, our group has evaluated diabetic changes in the compressive [2,3] and histomorphological [4] properties of the plantar soft tissue. We also recently obtained the corresponding shear properties from the specimens previously tested in compression [5].…”