Assessment of skin viability: is it necessary to use different methodologies?

Background/aim: Skin is complex and may display variable structural and metabolic change ‘ex vivo’. The present study aimed to follow measures of skin viability and evaluate their usefulness as markers of viability. Materials and methods: We evaluated the viability of skin samples fresh or after being frozen and subsequently thawed. Assessments included histopathological appearance, lactate dehydrogenase (LDH) activity, oxygen consumption and skin pH. Results: Morphological investigations of fresh and frozen skin samples using light and electron microscopy showed samples with relatively well‐defined epidermis and dermis. Frozen samples showed some sign of stratum corneum fragmentation, although this was not obvious. LDH activity measured in fresh samples kept at 4°C was low, but it was stable up to 7 days. Fresh samples kept at 32°C had a comparable LDH activity to the ones kept in the fridge up to 4 days. Frozen samples, thawed and then kept at 4°C showed a stable LDH activity after 24 h of incubation. However, frozen samples incubated at 32°C demonstrated a high variability in results, with up to 800 U/L of LDH activity after 5 days of incubation. Freshly excised as well as freshly thawed samples showed the highest respiration rates. Fresh and thawed samples stored for a long period of time had a significantly lower (sometimes non‐existent) oxygen consumption rate. Our results also showed an increase in the oxygen consumption rate of fresh samples being incubated at 32°C for 24 h. The oxygen consumption rate for all samples reached a plateau within the 15‐min measurement period and even the fresh samples did not deplete all the oxygen from the medium. Skin samples ex vivo showed a significantly higher pH than human skin in vivo, and when incubated for 46 h at 32°C, fresh samples had a significantly lower pH than frozen samples. All protocols were reproducible and freshly excised and freshly thawed skin samples showed the highest rates of viability. Conclusion: ex vivo skin shows variation of several parameters over time. It is recommended to use two or three techniques for evaluation of skin viability including at least oxygen measurement and an enzyme assay.     

Renal N(epsilon)-carboxymethyllysine deposition after kidney transplantation

BACKGROUND: Accumulation of advanced glycation end products, that is, N(epsilon)-carboxymethyllysine (CML), induces oxidative stress and inflammation, and is present in chronic renal failure. Proximal tubular cells (PTCs) take up advanced glycation end products-bound proteins by apical megalin-receptors and degrade them. We hypothesized that renal transplant dysfunction affects renal CML homeostasis. Therefore, tubular and glomerular deposition of CML was investigated in a rat transplantation model, and in human allograft biopsies. METHODS: Fisher 344 kidneys were orthotopically transplanted into Lewis recipients. Recipients were treated with placebo, angiotensin II type 1 receptor blocker (candsartan 5 mg/kg/day), or calcium channel blocker (lacidipine 1 mg/kg/day) more than 28 weeks posttransplantation. Grafts were harvested at 12, 20, and 28 weeks posttransplantation. Sixty-two renal transplant patients underwent graft biopsy because of creatinine increase. Biopsies were graded according to interstitial fibrosis and tubular atrophy. N(epsilon)-carboxymethyllysine and megalin were semiquantitatively investigated in rats and humans using immunohistochemistry. RESULTS: In Fisher grafts, the development of transplant dysfunction was associated with a longitudinal increase in CML deposition in PTCs (week 12: 1.0+/-0.0, week 20: 1.5+/-0.3, week 28: 2.1+/-0.2, P<0.05). No glomerular deposition was present. In human graft biopsies, tubular CML deposition was negatively, and glomerular CML deposition was positively associated with transplant dysfunction (r=-0.29 and r=0.34; P<0.05). Megalin was reduced at advanced grades. CONCLUSION: N(epsilon)-carboxymethyllysine deposition increased in rat PTCs with mild transplant dysfunction. In humans, tubular CML deposition decreased in parallel with the reduction of its cellular uptake mechanism (megalin). Furthermore, glomerular deposition could play a pathophysiological role in chronic allograft injury.     

Quality of life and psychological adaptation of Korean adolescents with vitiligo

Aim The aim of the study was to evaluate the impact of vitiligo on the quality of life and psychological adaptation in a Korean adolescent population. Methods Fifty‐seven adolescents aged 12 to 18 years with vitiligo were evaluated using self‐report scales, namely the Skindex‐29, Piers‐Harris self‐concept, Center for Epidemiologic Studies Depression Scale (CES‐D), and Revised Children’s Manifest Anxiety Scale (RCMAS). Results Mean Skindex‐29 subscales were as follow; 21.8 (global), 16.3 (symptom), 18.6 (function) and 29.5 (emotion). Several clinical variables, such as duration of vitiligo, facial involvement, history of previous treatment, and patient‐assessed severity, affected the Skindex‐29 subscales in various ways. However, differences in Skindex‐29 scores according to the type of vitiligo, extent of involvement, and family history were not observed. The Piers‐Harris self‐concept scores showed a negative correlation with Skindex‐29 scores, while other psychological measures (CES‐D and RCMAS) were positively correlated. Conclusion The quality of life of adolescents with vitiligo is closely related to the patients’ apprehensions about their disease, psychosocial adjustment, and psychiatric morbidity, rather than the clinical severity of the condition itself. Clinicians should recognize and deal with psychological adaptation along with medical intervention when treating adolescent patients with vitiligo.     

Hypopigmented keratosis: is it a hyperkeratotic variant of idiopathic guttate hypomelanosis?

We have occasionally seen patients with acquired well‐demarcated, scattered hypopigmented papules. In this study, we investigated the clinical and histopathological characteristics of such lesions. Biopsies were taken from the lesional and perilesional normal skin from 10 of 13 patients, which were compared with 10 idiopathic guttate hypomelanosis (IGH) samples. The lesions were scattered, well‐circumscribed, flat‐topped, hypopigmented papules. There was no age or gender predilection. Marked hyperkeratosis was present, with clear‐cut margins distinguishable from the adjacent normal epidermis. The melanin content was decreased in the lesional epidermis, which was associated with a decrease in expression of melanogenesis‐associated markers such as tyrosinase and NKI/beteb (marker of gp100) and reduction in the number of melanocytes. These histological findings were similar to those of IGH except for the additional finding of a thicker stratum corneum in this case seem to represent a ‘hyperkeratotic’ variant of IGH.     

Involvement of T cells in early evolving segmental vitiligo

Recent studies have suggested an overlapping autoimmune mechanism between segmental vitiligo (SV) and nonsegmental vitiligo (NSV). Although T‐cell infiltration is observed in the margins of active lesions in NSV, the histopathological characteristics of the active margin of SV are not well known. To determine if T‐cell inflammatory responses are present in the active margin of SV lesions, biopsies were taken from the active margin of a lesion in 12 patients with early or actively spreading SV and compared with a normal control sample (on the symmetrical, opposite site of the same dermatome). The samples were stained for CD4, CD8, CD25 and interferon‐γ. Lymphocytic infiltration was seen in 70% of patients. CD4+ T cells infiltrated the dermis, while CD8+ T cells were present in the epidermis or attached to the basal layer. The increase in the number of CD8+ T cells was significant (P < 0.04), while CD4+ or CD25+ T cells also appeared to be increased in number, but this was not significant. These results suggest that SV also has an autoimmune mechanism in the early evolving stage.     

Addressing extreme size mismatch in pediatric intestinal transplantation: Outcomes of intestinal length reduction

Background

Bench liver reduction, with or without intestinal length reduction (LR) (coupled with delayed closure and abdominal wall prostheses), has been a strategy adopted by our program for small children due to the limited availability of size-matched donors. This report describes the short, medium, and long-term outcomes of this graft reduction strategy.

Methods

A single-center, retrospective analysis of children that underwent intestinal transplantation (April 1993 to December 2020) was performed. Patients were grouped according to whether they received an intestinal graft of full length (FL) or following LR.

Results

Overall, 105 intestinal transplants were performed. The LR group (n = 10) was younger (14.5 months vs. 40.0 months, p = .012) and smaller (8.7 kg vs. 13.0 kg, p = .032) compared to the FL group (n = 95). Similar abdominal closure rates were achieved after LR, without any increase in abdominal compartment syndrome (1/10 vs. 7/95, p = .806). The 90-day graft and patient survival were similar (9/10, 90% vs. 83/95, 86%; p = .810). Medium and long-term graft survival at 1 year (8/10, 80% vs. 65/90, 71%; p = .599), and 5 years (5/10, 50% vs. 42/84, 50%; p = 1.00) was similar.

Conclusion

LR of intestinal grafts appears to be a safe strategy for infants and small children requiring intestinal transplantation. This technique should be considered in the situation of significant size mismatch of intestine containing grafts.