Primary Graft Function and 5 Year Insulin Independence After Pancreas and Islet Transplantation for Type 1 Diabetes: A Retrospective Parallel Cohort Study

In islet transplantation (ITx), primary graft function (PGF) or beta cell function measured early after last infusion is closely associated with long term clinical outcomes. We investigated the association between PGF and 5 year insulin independence rate in ITx and pancreas transplantation (PTx) recipients. This retrospective multicenter study included type 1 diabetes patients who underwent ITx in Lille and PTx in Nantes from 2000 to 2022. PGF was assessed using the validated Beta2-score and compared to normoglycemic control subjects. Subsequently, the 5 year insulin independence rates, as predicted by a validated PGF-based model, were compared to the actual rates observed in ITx and PTx patients. The study enrolled 39 ITx (23 ITA, 16 IAK), 209 PTx recipients (23 PTA, 14 PAK, 172 SPK), and 56 normoglycemic controls. Mean[SD] PGF was lower after ITx (ITA 22.3[5.2], IAK 24.8[6.4], than after PTx (PTA 38.9[15.3], PAK 36.8[9.0], SPK 38.7[10.5]), and lower than mean beta-cell function measured in normoglycemic control: 36.6[4.3]. The insulin independence rates observed at 5 years after PTA and PAK aligned with PGF predictions, and was higher after SPK. Our results indicate a similar relation between PGF and 5 year insulin independence in ITx and solitary PTx, shedding new light on long-term transplantation outcomes.

Cognitive Outcome After Islet Transplantation

Severe or repeated hypoglycemia events may favor memory complaints in type 1 diabetes (T1D). Pancreatic islet transplantation (IT) is an alternative option to exogenous insulin therapy in case of labile T1D, implying a maintenance immunosuppression regimen based on sirolimus or mycophenolate, associated with tacrolimus, that may also have neurological toxicity. The objective of this study was to compare a cognitive rating scale Mini-Mental State Examination (MMSE) between T1D patients with or without IT and to identify parameters influencing MMSE.

Methods

This retrospective cross-sectional study compared MMSE and cognitive function tests between islet-transplanted T1D patients and nontransplanted T1D controls who were transplant candidates. Patients were excluded if they refused.

Results

Forty-three T1D patients were included: 9 T1D patients before IT and 34 islet-transplanted patients (14 treated with mycophenolate and 20 treated with sirolimus). Neither MMSE score (P = 0.70) nor higher cognitive function differed between islet versus non-islet-transplanted patients, whatever the type of immunosuppression. In the whole population (N = 43), MMSE score was negatively correlated to glycated hemoglobin (r = -0.30; P = 0.048) and the time spent in hypoglycemia on the continuous glucose monitoring (r = -0.32; P = 0.041). MMSE score was not correlated to fasting C-peptide level, time spent in hyperglycemia, average blood glucose, time under immunosuppression, duration of diabetes, or beta-score (success score of IT).

Conclusions

This first study evaluating cognitive disorders in islet-transplanted T1D patients argues for the importance of glucose balance on cognitive function rather than of immunosuppressive treatment, with a favorable effect of glucose balance improvement on MMSE score after IT.

Structured surface reflector design for oblique incidence beam splitter at 610 GHz

An iterative alternate projection-based algorithm is developed to design structured surface reflectors to operate as beam splitters at GHz and THz frequencies. To validate the method, a surface profile is determined to achieve a reflector at 610 GHz that generates four equal-intensity beams towards desired directions of ±12.6° with respect to the specular reflection axis. A prototype is fabricated and the beam splitter behavior is experimentally demonstrated. Measurements confirm a good agreement (within 1%) with computer simulations using Feko, validating the method. The beam splitter at 610 GHz has a measured efficiency of 78% under oblique incidence illumination that ensures a similar intensity between the four reflected beams (variation of about 1%).

Management of endocrino-metabolic dysfunctions after allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation is mainly indicated in bone marrow dysfunction related to blood diseases, but also in some rare diseases (adrenoleucodystrophy, mitochondrial neurogastrointestinal encephalomyopathy or MNGIE…). After decades, this treatment has proven to be efficient at the cost of numerous early and delayed side effects such as infection, graft-versus-host disease, cardiovascular complications and secondary malignancies. These complications are mainly related to the conditioning, which requires a powerful chemotherapy associated to total body irradiation (myelo-ablation) or immunosuppression (non myelo-ablation). Among side effects, the endocrine complications may be classified as 1) hormonal endocrine deficiencies (particularly gonado- and somatotropic) related to delayed consequences of chemo- and above all radiotherapy, with their consequences on growth, puberty, bone and fertility); 2) auto-immune diseases, particularly dysthyroidism; 3) secondary tumors involving either endocrine glands (thyroid carcinoma) or dependent on hormonal status (breast cancer, meningioma), favored by immune dysregulation and radiotherapy; 4) metabolic complications, especially steroid-induced diabetes and dyslipidemia with their increased cardio-vascular risk. These complications are intricate. Moreover, hormone replacement therapy can modulate the cardio-vascular or the tumoral risk of patients, already increased by radiotherapy and chemotherapy, especially steroids and anthracyclins… Therefore, patients and families should be informed of these side effects and of the importance of a long-term follow-up requiring a multidisciplinary approach.

Treating diabetes with islet transplantation: lessons from the past decade in Lille

Type 1 diabetes (T1D) is due to the loss of both beta-cell insulin secretion and glucose sensing, leading to glucose variability and a lack of predictability, a daily issue for patients. Guidelines for the treatment of T1D have become stricter as results from the Diabetes Control and Complications Trial (DCCT) demonstrated the close relationship between microangiopathy and HbA1c levels. In this regard, glucometers, ambulatory continuous glucose monitoring, and subcutaneous and intraperitoneal pumps have been major developments in the management of glucose imbalance. Besides this technological approach, islet transplantation (IT) has emerged as an acceptable safe procedure with results that continue to improve. Research in the last decade of the 20th century focused on the feasibility of islet isolation and transplantation and, since 2000, the success and reproducibility of the Edmonton protocol have been proven, and the mid-term (5-year) benefit-risk ratio evaluated. Currently, a 5-year 50% rate of insulin independence can be expected, with stabilization of microangiopathy and macroangiopathy, but the possible side-effects of immunosuppressants, limited availability of islets and still limited duration of insulin independence restrict the procedure to cases of brittle diabetes in patients who are not overweight or have no associated insulin resistance. However, various prognostic factors have been identified that may extend islet graft survival and reduce the number of islet injections required; these include graft quality, autoimmunity, immunosuppressant regimen and non-specific inflammatory reactions. Finally, alternative injection sites and unlimited sources of islets are likely to make IT a routine procedure in the future.

Continuous glucose monitoring after islet transplantation in type 1 diabetes: an excellent graft function (β-score greater than 7) Is required to abrogate hyperglycemia, whereas a minimal function is necessary to suppress severe hypoglycemia (β-score greater than 3)

CONTEXT

For the last 10 yr, continuous glucose monitoring (CGM) has brought up new insights into the accuracy of blood glucose analysis.

OBJECTIVE

Our objective was to determine how islet graft function was able to influence the various components of dysglycemia after islet transplantation (IT).

DESIGN AND SETTING

We conducted a single-arm open-labeled study with a 3-yr follow-up in a referral center (ClinicalTrial.gov identifiers NCT00446264 and NCT01123187).

PATIENTS

Twenty-three consecutive patients with type 1 diabetes (14 islet alone, nine islet after kidney) received IT within 3 months using the Edmonton protocol.

INTERVENTION

INTERVENTION included 72-h CGM before and 3, 6, 9, 12, 24, and 36 months after transplantation.

MAIN OUTCOME MEASURE

Graft function was estimated via β-score, a previously validated index (range 0-8) based on treatment requirements, C-peptide, blood glucose, and glycated hemoglobin.

RESULTS

At the 3-yr visit, graft function persisted in 19 patients (82%), and 10 (43%) remained insulin independent. Glycated hemoglobin decreased in the whole cohort from 8.3% (7.3-9.0%) at baseline to 6.7% (5.9-7.7%) at 3 yr [median (interquartile range), P < 0.01]. Mean glucose, glucose sd, and time spent with glycemia above 10 mmol/liter (hyperglycemia) and below 3 mmol/liter (hypoglycemia) were significantly lower after IT (P < 0.05 vs. baseline). The four CGM outcomes were related to β-score (P < 0.001). However, partial function (β-score >3) was sufficient to abrogate hypoglycemia; suboptimal function (β-score >5) was necessary to significantly improve mean glucose, glucose sd, and hyperglycemia; and optimal function (β score >7) was necessary to normalize them.

CONCLUSION

The four components of dysglycemia were not equally affected by the degree of islet graft function, which could have important implications for future development of β-cell replacement. A β-score above 3 dramatically reduced the occurrence of hypoglycemia.

How to diagnose a lipodystrophy syndrome

The spectrum of adipose tissue diseases ranges from obesity to lipodystrophy, and is accompanied by insulin resistance syndrome, which promotes the occurrence of type 2 diabetes, dyslipidemia and cardiovascular complications. Lipodystrophy refers to a group of rare diseases characterized by the generalized or partial absence of adipose tissue, and occurs with or without hypertrophy of adipose tissue in other sites. They are classified as being familial or acquired, and generalized or partial. The genetically determined partial forms usually occur as Dunnigan syndrome, which is a type of laminopathy that can also manifest as muscle, cardiac, neuropathic or progeroid involvement. Gene mutations encoding for PPAR-gamma, Akt2, CIDEC, perilipin and the ZMPSTE 24 enzyme are much more rare. The genetically determined generalized forms are also very rare and are linked to mutations of seipin AGPAT2, FBN1, which is accompanied by Marfan syndrome, or of BANF1, which is characterized by a progeroid syndrome without insulin resistance and with early bone complications. Glycosylation disorders are sometimes involved. Some genetically determined forms have recently been found to be due to autoinflammatory syndromes linked to a proteasome anomaly (PSMB8). They result in a lipodystrophy syndrome that occurs secondarily with fever, dermatosis and panniculitis. Then there are forms that are considered to be acquired. They may be iatrogenic (protease inhibitors in HIV patients, glucocorticosteroids, insulin, graft-versus-host disease, etc.), related to an immune system disease (sequelae of dermatopolymyositis, autoimmune polyendocrine syndromes, particularly associated with type 1 diabetes, Barraquer-Simons and Lawrence syndromes), which are promoted by anomalies of the complement system. Finally, lipomatosis is currently classified as a painful form (adiposis dolorosa or Dercum's disease) or benign symmetric multiple form, also known as Launois-Bensaude syndrome or Madelung's disease, which are sometimes related to mitochondrial DNA mutations, but are usually promoted by alcohol. In addition to the medical management of metabolic syndrome and the sometimes surgical treatment of lipodystrophy, recombinant leptin provides hope for genetically determined lipodystrophy syndromes, whereas modifications in antiretroviral treatment and tesamorelin, a GHRH analog, is effective in the metabolic syndrome of HIV patients. Other therapeutic options will undoubtedly be developed, dependent on pathophysiological advances, which today tend to classify genetically determined lipodystrophy as being related to laminopathy or to lipid droplet disorders.

11β-hydroxystéroïde déshydrogénases. Avancées récentes

11beta-hydroxysteroide dehydrogenase (11beta-OHSD) enzymes exhibit a regulating action upon cortisol metabolism before access to its receptors. Two types of isoenzymes have been described, type 2 being the most anciently known. Type 2 11beta-OHSD, which changes cortisol into cortisone, is a unidirectional dehydrogenase mainly located in kidney, that protects mineralocorticoid receptors from illicit activation by glucocorticoids. Mutations of the gene coding for this enzyme has been demonstrated in apparent mineralocorticoid excess, which induces hypertension and hypokalemia with low renin and aldosterone levels. Polymorphisms of this gene could modulate essential hypertension and also be responsible for certain forms of acquired apparent mineralocorticoid excess especially after liquorice intoxication, in hypothyroidism, Cushing syndrome, and chronic renal insufficiency. Type 1 11beta-OHSD, which changes cortisone into cortisol, is a reductase, mainly located in liver and adipose tissue. Functional defects of this enzyme have been shown in polycystic ovaries and cortisone reductase deficiency. By contrast, metabolic syndrome, corticoid-induced osteoporosis, and glaucoma are linked to a local over-activity of this enzyme. The understanding of action mechanisms of these two enzymes currently leads to 11beta-OHSD inhibitors development, therefore opening new therapeutic strategies, especially in metabolic syndrome.