New Histologic Finding of Amyloid Insulin Bodies at an Insulin Injection Site in a Patient With Diabetes

Comprehensive investigation of insulin-induced amyloidosis lesions in patients with diabetes at clinical and histological levels: A systematic review

INTRODUCTION

Insulin-derived amyloidosis (AIns), a skin complication in patients with diabetes, causes impaired insulin absorption. This systematic review aims to get a better understanding of this overlooked condition.

METHODS

Comprehensive literature searches were performed in Scopus, PubMed, EMBASE, and Web of Science databases until June 17, 2023. From 19,343 publications, duplicate and irrelevant records were eliminated by title, and the full texts of the remaining studies were examined for validity. Clinical, pathological, and therapeutic findings were extracted from 44 papers.

RESULTS

Forty-four articles were studied that covered 127 insulin-treated patients with diabetes. From the 62 patients with reported age and sex, males had a mean age of 58 years, and females 68.5 years. While AIns were twice as likely to develop in men (66.13 %) as in women (33.87 %), the administered insulin dose was significantly higher in males (p = 0.017). The most common insulin injection site was the abdominal wall (77.63 %). Histological findings showed the presence of amorphous material with the occasional presence of lymphocytes, plasma cells, macrophages, adipocytes, histocytes, and giant cells. The mean HbA1c level was 8.8 % and the need for receiving insulin was increased in AIns. Changing the site of insulin injections and/or surgically removing the nodules were the most common treatments to obtain better insulin uptake and controlled serum glucose levels.

CONCLUSION

This study highlights the importance of AIns, proper rotation of insulin injection site, and post-treatment patient follow-up to recognize and prevent the development of amyloid nodules.

Differences in clinicopathological characteristics between lipohypertrophy and localized insulin-derived amyloidosis: A scoping review

Insulin is used as a therapeutic agent in patients with diabetes, and cutaneous lipohypertrophy (LH) and localized insulin-derived amyloidosis (LIDA) are well-known adverse effects associated with insulin injections. The clinical implications, management, assessment methods, and pathological differentiation of LH and LIDA have been recently updated. This review was to update our knowledge of the pathological differentiation, effects of insulin absorption, hypoglycemic events, and recent assessment methods for LH and LIDA. A scoping review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta Analyses extension for Scoping Reviews guidelines. Original studies and case reports in English were also included. PubMed and Scopus databases were searched for keywords to identify papers published up to January 2022. A total of 113 studies were identified through a database search, and 31 were eligible for inclusion in this scoping review. In the 31 studies included in this review, patients with type 2 diabetes had high frequencies of LH and LIDA. LH outcome parameters were assessed using pathological findings and imaging. LIDA is mainly determined by pathological methods, such as hematoxylin and eosin and Congo red staining. Several in vitro and in vivo LIDA models of LIDA have been developed. These results suggest that pathological analysis is required to identify LH and LIDA. It is important to consider LIDA, as it likely influences insulin adsorption and glycemic control. Although several studies have evaluated the LIDA process, little is known about the mechanisms underlying the development of adverse effects associated with insulin injections.

Insulin Fibril Formation Caused by Mechanical Shock and Cavitation

Cavitation can occur when liquids are exposed to pressure waves of sufficient amplitude, producing rapidly expanding and collapsing gas bubbles that generate localized regions of high energy dissipation. When vials containing insulin were subjected to mechanical shock or when ultrasound was applied to the vials, the resulting cavitation events induced formation of insulin amyloid fibril nuclei that were detected by transmission electron microscopy and quantified by fluorescence spectroscopy following staining with the amyloid-sensitive dye thioflavin-T. Dropping insulin solutions in glass vials produced only minute amounts of insulin fibril nuclei, which could be detected by allowing the nuclei to grow. Cavitation-induced formation of amyloid aggregates may be relevant for iatrogenic insulin deposition disease, where insulin fibrils formed in vitro prior to administration to patients could serve as nuclei for growing fibril deposits in vivo.

Abdominal fat pad biopsies exhibit good diagnostic accuracy in patients with suspected transthyretin amyloidosis

Background

The diagnostic accuracy of histopathological detection of transthyretin amyloid (ATTR) by Congo red staining of abdominal fat samples has been questioned since low sensitivity has been reported, especially for patients with ATTR cardiomyopathy. However, the outcome of surgically obtained fat pad biopsies has not yet been evaluated. The aim was to evaluate the diagnostic accuracy of skin punch biopsies from abdominal fat in patients with suspected ATTR amyloidosis.

Material and methods

Data were evaluated from patients who had undergone abdominal fat pad biopsies using a skin punch due to suspected amyloidosis from 2006 to 2015. The biopsies had been analysed using Congo red staining to determine the presence of amyloid, and immunohistochemistry or Western blot to determine the type of amyloidosis. The final diagnosis was based on the clinical picture, biopsy results and DNA sequencing. Minimum follow-up after the initial biopsy was 3 years.

Results

Two hundred seventy-four patients (61% males) were identified, and in 132 (48%), a final diagnosis of amyloidosis had been settled. The majority (93%) had been diagnosed with hereditary transthyretin (ATTRv) amyloidosis, and therefore subsequent analyses were focused on these patients. Overall, our data showed a test specificity of 99% and a sensitivity of 91%. Ninety-eight (94%) of the patients had neuropathic symptoms at diagnosis, whereas 57 (55%) had signs of amyloid cardiomyopathy. Subgroup analyses showed that patients with merely neuropathic symptoms displayed the highest test sensitivity of 91%, whereas patients with pure cardiomyopathy displayed the lowest sensitivity of 83%. However, no significant differences in sensitivity were found between patients with or without cardiomyopathy or between the sexes.

Conclusions

Abdominal fat pad biopsies exhibit good diagnostic accuracy in patients with suspect ATTRv amyloidosis, including patients presenting with cardiomyopathy. In addition, the method enables typing not only of the precursor protein but also of the amyloid fibril type, which is related to the phenotype and to the outcome of the disease.

An abdominal wall mass of exogenous insulin amyloidosis in setting of metastatic sarcoma

Exogenous insulin amyloidosis (AIns) is an iatrogenic form of amyloidosis which is found in diabetic patients, generally localized to the site of subcutaneous insulin administration. It may form a discrete mass that could come to clinical attention, and can contribute to abnormal pharmacokinetics of the exogenous insulin, resulting in worsened control of diabetes. In this case report, we describe such a lesion in a 72-year-old man with a history of type 2 diabetes and primary adrenal gland epithelioid sarcoma and discuss the diagnostic challenges it poses.

Extreme Adhesion Activity of Amyloid Fibrils Induces Subcutaneous Insulin Resistance

Insulin-derived amyloidoma, also called an insulin ball, is a skin-related complication of insulin therapy caused by repeated insulin injections at the same site, where native folded insulin changes into amyloid fibrils and forms a mass with a granulomatous reaction. Insulin-derived amyloidoma is a clinically important condition because of its association with subcutaneous insulin resistance, but the precise effect and mechanism of the insulin absorption impairment have not been clarified. We generated insulin-derived amyloidomas in mouse skin, with the amyloidomas large enough to perform insulin tolerance tests in the mass by repeated injections of highly concentrated insulin amyloid fibrils. We demonstrated that the insulin-derived amyloidomas inhibit insulin absorption. By simultaneous administration of insulin and insulin amyloid fibrils, we showed that this effect is due to the amyloid fibril itself in the absence of a granulomatous reaction. In vitro studies revealed that insulin amyloid fibrils have extremely strong adhesion to native human insulin and various insulin analogs. Furthermore, we showed that native insulin that had adhered to insulin amyloid forms amyloid fibrils at physiological pH. These results suggest that the extreme adhesion of insulin amyloid to native insulin is the main mechanism of impaired insulin absorption and amyloidoma growth.