Patients’ opinions 10 years after receiving encapsulated porcine islet xenotransplantation without immunosuppression

Previously we performed clinical encapsulated neonatal porcine islet transplantation under comprehensive regulation, and demonstrated the efficacy and safety. To analyze the patients’ quality of life (QOL), we assessed patients’ opinions 10 years after islet xenotransplantation.


INTRODUCTION
Currently, intensive insulin therapy is the standard treatment for type 1 diabetes, however, hypoglycemia is a critical limiting factor. 1 In fact, impaired awareness of hypoglycemia and severe hypoglycemic events cause substantial morbidity and mortality in type 1 diabetic patients. 2 There is no doubt that hypoglycemia can be fatal. 3 A closed-loop insulin pump could improve the glycemic control and reduce the hypoglycemic events, 4 especially in children, 5,6 but not completely prevent hypoglycemic events. In addition, with improved insulin therapy, the number of older adults with type 1 diabetic patients was increased, 7,8 and these patients had more severe hypoglycemic events. Furthermore, the severe hypoglycemic events could deteriorate cognitive function 7 which cause difficulty of intensive insulin therapy, and current advanced insulin therapy. 8,9 The older adults cannot fully benefit from these new technologies because their limited ability to manage these instruments due to cognitive and functional impairments makes it difficult to use these technologies. In fact, betacell replacement therapy is expected to treat the type 1 diabetic patients with the difficulty of insulin therapy. 8 Allogeneic islet transplantation can effectively prevent severe hypoglycemic events and provide excellent blood glucose control. 10 However, donor shortage of human organ for islet transplantation and the necessity of lifelong immunosuppression are two major issues to expand islet transplantation. 11 To overcome the two issues, we performed clinical encapsulated neonatal porcine islet transplantation under comprehensive regulation, and demonstrated the efficacy and safety. [12][13][14][15][16] On the other hand, diabetes is an incurable disease, therefore improving and maintaining a quality of life (QOL) is considered a goal of the treatment. QOL is assessed by the patients' own idea and feelings. Therefore, in this study, to analyze the patients' idea and feelings for encapsulated islet xenotransplantation without immunosuppressive therapy, we created questionnaires and analyze the data.

Ethics statement
The bioethical committee at Eva Peron hospital approved this survey study. The survey began in September 25th and ended in November 3rd, 2022.
The clinical trials were enrolled in the ClinicalTrials.gov and the identifier numbers were NCT01736228 and NCT01739829. The clinical trial protocol was granted ethics approval in Argentina from the Ministry of Health, Buenos Aires Province, and the local institutional ethics committee.

Patients
Patients' characteristics were shown in Table 1. 4. Plasma C-peptide less than 0.3 ng/mL following a glucagon stimulation test.
All patients were under intensive insulin therapy (more than three times insulin injection or using an insulin pump) before transplantation.
The encapsulated neonatal porcine islets were produced and transplanted as follows. 14  The groups 1 and 2 were assessed safety (cancer and serious adverse event) and efficacy (HbA1c and insulin dose) and group 3 was assessed only safety (cancer and adverse events).

Questionnaire procedure
The actual questions consisted of two parts. The first part includes how encapsulated islet xenotransplantation improved or deteriorated (A) management of diabetes, (B) blood sugar levels, (C) frequency of severe hypoglycemia, and (D) frequency of hyperglycemia episodes requiring hospitalization (Table 3). There were eight categories for choice, question A and B use the same categories, and question C and D use the same categories (Table 3). The second part consisted 14 questions as shown in Table 4.
The actual survey procedure is as follows. The patients arrived at the hospital at different times without any contact between them. A questioner sat with each patient in an isolated room, with one copy of the questionnaire for the patient and one for the questioner, and explained the multiple-choice methodology to him/her and read each question to him/her, asking if he/she understood it. Otherwise, a questioner would explain it to him/her. None of the questioner's interventions induced any kind of response. Once the questions were read, the patient began to answer the questionnaire. Once this step was finished the questioner verified that all the questions were answered then the patient left.

Statistics
To demonstrate individual efficacy of transplantation, average HbA1c and insulin dose 3 months before transplantation and after transplantation were statistically assessed using Student's t-test. Outcomes of HbA1c and insulin doses pre-transplantation and in the survey were statistically assessed using Student's t-test. MicrosoftExcel 2019 was used for the statistical analysis.
p < .05 was considered as a significant difference.

Efficacy outcomes of group 1 and 2
After transplantation all patients significantly improved HbA1c, and five out of seven patients significantly reduced insulin doses (

Safety outcomes
No patients reported any cancer. One patient reported serious adverse event which was retinopathy (Table 7).

Questionnaire outcomes
For the first part of the questionnaire, compared with before transplan-  For the second part of the questionnaire, at first none of the patients suffered cancer, even 10 years after transplantation (Table 7). Only one severe adverse event which was diabetes retinopathy.
Regarding improved relationship with family, with employers, with partner, the majority of patients selected negative answers. On the other hand, the majority of patients selected transplantation has given more security in life. This might reflect, the transplantation provided the patients more security, therefore, the patients need less third party help.
The majority of patients selected positive replies for receiving islet xenotransplantation again and recommending to other people.
Regarding concern about animal cells and porcine virus, only minor patients were afraid of them. In fact, all patients replied that the trial administrators and health professionals protect adequately. It seems that an adequate explanation of the risks can mitigate the concerns.
No patients selected psychological problems and abuse for receiving pig cells.

DISCUSSION
Previously we demonstrated clinical efficacy 12,14 and long-term safety 16 of encapsulated neonatal porcine islet transplantation for the treatment of unstable type 1 diabetes.
On the other hand, diabetes is incurable disease, therefore, improving and maintaining the QOL is one of the goals of the treatment of diabetes. Since QOL is judged by patients own ideas and feelings, we conducted a questionnaire survey of the patients who received encapsulated islet xenotransplantation after approximately 10 years of transplantation.
In order to improve and maintain QOL, encapsulated islet should provide clinical efficacy. When compared before transplantation and after transplantation, all patients significantly improved HbA1c and majority of patient reduced insulin dose after transplantation (Table 5).
Furthermore, we found all patients improved HbA1c and reduced daily insulin doses at the time of the survey compared to pre-transplantation (Table 6). Previously we demonstrated encapsulated porcine islets could survive 9.5 years after transplantation. 17 This suggested that survived porcine islets might play a role to improve the clinical efficacy outcomes.
Importantly, nobody suffered any cancer and this seems reasonable since no patients use immune suppressive drugs. It was reported that the incidence of malignancy except for skin cancer has estimated at 20% after 10 years of chronic immunosuppression. 18 Furthermore, it was reported that the rate of skin cancer in kidney transplantation was 45% after 11 years 19 and in cardiac transplantation was 43% after 10 years 20 in Australia. No side effects of immunosuppression definitely provide better QOL for the patients who received encapsulated porcine islet transplantation.
In addition, only one serious adverse event was reported which was retinopathy. It is reasonable to consider this adverse event was associated with poor glycemic control. Intraperitoneal implantation of encapsulated porcine islet xenotransplantation can be considered a safe treatment for up to approximately 10 years.
Regarding, diabetes management, blood sugar level, severe hypoglycemia, and hyperglycemia no patients selected negative answers.
This indicated that from patients' point of view, the worst case of the treatment was simply returned to pre-transplant situation.    Secondarily, all replies are subjective by the patients. Since all patients selected that the trial administrators and health professionals protected the patients during the trial adequately, the patients might put a positive reply because of excellent service instead of islet xenotransplantation itself.
In conclusion, based on this questionnaire survey, the majority of patients who received encapsulated porcine islet transplantation