Deep epigastric lymph nodes implication in patients' recurrence pattern after cytoreductive surgery in ovarian peritoneal metastases

INTRODUCTION

Although complete cytoreductive surgery (CRS) with or without hyperthermic intraperitoneal chemotherapy (HIPEC) offers a good prognosis in patients with peritoneal metastasis of ovarian cancer (PMOC), recurrences are quite common. These recurrences can be intra-abdominal or systemic in nature. Our objective was to study and illustrate the global recurrence pattern in patients operated for PMOC, shedding light on a previously overlooked lymphatic basin at the level of the epigastric artery, the deep epigastric lymph nodes (DELN) basin.

PATIENTS AND METHODS

This was a retrospective study including patients with PMOC who underwent surgery with curative-intent, from 2012 until 2018, at our cancer center, and who presented with any type of disease recurrence on follow-up. CT-scans, MRIs and PET-scans were reviewed in order to determine solid organs and lymph nodes (LN) recurrences.

RESULTS

During the study period, 208 patients underwent CRS ± HIPEC, 115 (55.3%) presented with organ or lymphatic recurrence over a median follow-up of 81 months. Sixty percent of these patients had radiologically enlarged LN involvement. The pelvis/pelvic peritoneum was the most common intra-abdominal organ recurrence site (47%), while the retroperitoneal LN was the most common lymphatic recurrence site (73.9%). Previously overlooked DELN were found in 12 patients, with 17.4% implication in lymphatic basin recurrence patterns.

CONCLUSION

Our study revealed the potential role of the DELN basin, previously overlooked in the systemic dissemination process of PMOC. This study sheds light on a previously unrecognized lymphatic pathway, as an intermediate checkpoint or relay, between the peritoneum, an intra-abdominal organ, and the extra-abdominal compartment.

Uterine embryonal rhabdomyosarcoma in adult women: a case report on the challenging diagnosis and treatment

BACKGROUND

Uterine embryonal rhabdomyosarcoma (uERMS) in adult women is a very rare malignant entity. The study aim was to report a case of adult uERMS and to discuss the implications of histopathological diagnosis on the treatment and prognosis.

CASE PRESENTATION

We present here the clinicopathological features of a uERMS case in an adult woman. The study has been approved by the institutional Ethics Committee and an informed consent has been obtained (IJB∕CE3005). A 45-year-old woman presented to her gynecologist with intermenstrual bleedings and polypoid cervical mass (initially interpreted as benign polyp). A second biopsy was sent to our Department of Pathology at the Jules Bordet Institute, Brussels, Belgium for revision and was reinterpreted as botryoid-type uERMS. The patient underwent a total hysterectomy. The final pathology confirms a 3 cm cervical ERMS, and a simple surveillance was decided by our multidisciplinary team. Six months later, pelvic magnetic resonance imaging control showed a recurrence in the right pelvic lymph nodes. Multi-drug chemotherapy and radiotherapy were done before surgical resection. Pathological examination of the resected pelvic mass confirmed uERMS recurrence of 60 mm, with large zones of necrosis and the presence of cartilaginous structures. The patient is free of disease 60 months after diagnosis.

CONCLUSIONS

Adult uERMS is rare and the pathological examination is the main element for diagnosis and treatment. It is often confused with other benign entities, at least at the time of diagnosis. ERMS should be included in the differential diagnosis of cervical and uterine polyp of adult women. Long-term survival is possible with a multimodal therapy approach.

Intraoperative electron radiotherapy in early invasive ductal breast cancer: 6-year median follow-up results of a prospective monocentric registry

Background

Intraoperative electron radiotherapy (IOERT) can be used to treat early breast cancer during the conservative surgery thus enabling shorter overall treatment times and reduced irradiation of organs at risk. We report on our first 996 patients enrolled prospectively in a registry trial.

Methods

At Jules Bordet Institute, from February 2010 onwards, patients underwent partial IOERT of the breast. Women with unifocal invasive ductal carcinoma, aged 40 years or older, with a clinical tumour size ≤ 20 mm and tumour-free sentinel lymph node (on frozen section and immunohistochemical analysis). A 21 Gy dose was prescribed on the 90% isodose line in the tumour bed with the energy of 6 to 12 MeV (Mobetron®-IntraOp Medical).

Results

Thirty-seven ipsilateral tumour relapses occurred. Sixteen of those were in the same breast quadrant. Sixty patients died, and among those, 12 deaths were due to breast cancer. With 71.9 months of median follow-up, the 5-year Kaplan–Meier estimate of local recurrence was 2.7%.

Conclusions

The rate of breast cancer local recurrence after IOERT is low and comparable to published results for IORT and APBI. IOERT is highly operator-dependent, and appropriate applicator sizing according to tumour size is critical. When used in a selected patient population, IOERT achieves a good balance between tumour control and late radiotherapy-mediated toxicity morbidity and mortality thanks to insignificant irradiation of organs at risk.

Literature review and case report of bilateral intracystic papillary carcinoma associated with an invasive ductal carcinoma in a male breast

Intracystic papillary carcinoma (IPC) is a rare tumor with good prognosis that occurs in only 5% to 7.5% of male breast cancer. We report a case of a 46-year-old man who presented a brown nipple discharge a few months ago. He had a bilateral IPC and an invasive ductal carcinoma on the right breast. A double mastectomy was then performed with a bilateral sentinel lymph node biopsy, and he received chemotherapy, radiotherapy, and hormonotherapy. Two years after the diagnosis, the patient recovered and was free of recurrence. Considering the scarcity of this tumor type, we conducted a systematic literature review on the PubMed of all the cases of IPC in men. The clinical presentation, imaging, and treatment of the 43 case reports from the 41 articles selected were described. Furthermore, no clear guidelines for IPC management are available. Conservative surgery should also be preferred, and a sentinel lymph node biopsy should be performed systematically. Moreover, radiotherapy should be proposed in the case of conservative surgery, and hormone therapy could be proposed in the case of invasive IPC or IPC associated with a ductal carcinoma in situ.

Near-Infrared Fluorescence Imaging of Breast Cancer and Axillary Lymph Nodes After Intravenous Injection of Free Indocyanine Green

Background

Near-infrared fluorescence imaging (NIRFI) of breast cancer (BC) after the intravenous (IV) injection of free indocyanine green (fICG) has been reported to be feasible. However, some questions remained unclarified.

Objective

To evaluate the distribution of fICG in BC and the axillary lymph nodes (LNs) of women undergoing surgery with complete axillary LN dissection (CALND) and/or selective lymphadenectomy (SLN) of sentinel LNs (NCT no. 01993576 and NCT no. 02027818).

Methods

An intravenous injection of fICG (0.25 mg/kg) was administered to one series of 20 women undergoing treatment with mastectomy, the day before surgery in 5 (group 1) and immediately before surgery in 15 (group 2: tumor localization, 25; and pN+ CALND, 4) as well as to another series of 20 women undergoing treatment with tumorectomy (group 3). A dedicated NIR camera was used for ex vivo fluorescence imaging of the 45 BC lesions and the LNs.

Results

In group 1, two of the four BC lesions and one large pN+ LN exhibited fluorescence. In contrast, 24 of the 25 tumors in group 2 and all of the tumors in group 3 were fluorescent. The sentinel LNs were all fluorescent, as well as some of the LNs in all CALND specimens. Metastatic cells were found in the fluorescent LNs of the pN+ cases. Fluorescent BC lesions could be identified ex vivo on the surface of the lumpectomy specimen in 14 of 19 cases.

Conclusions

When fICG is injected intravenously just before surgery, BC can be detected using NIRFI with high sensitivity, with metastatic axillary LNs also showing fluorescence. Such a technical approach seems promising in the management of BC and merits further investigation.

Absence of residual fluorescence in the surgical bed at near-infrared fluorescence imaging predicts negative margins at final pathology in patients treated with breast-conserving surgery for breast cancer

INTRODUCTION

Positive margins after breast-conserving surgery (BCS) for breast cancer (BC) remain a major concern. In this study we investigate the feasibility and accuracy of indocyanine green (ICG) fluorescence imaging (FI) for the in vivo assessment of surgical margins during BCS.

MATERIALS AND METHODS

Patients with BC admitted for BCS from October 2015 to April 2016 were proposed to be included in the present study (NCT02027818). ICG (0.25 mg/kg) was intravenously injected at induction anesthesia and ICG-FI of the surgical beds was correlated with final pathology results.

RESULTS

Fifty patients consented to participate and thirty-five patients were retained for final analysis, 15 patients having been excluded for, respectively, incomplete video records data for signal to background ratio (SBR) calculation (11) and in situ tumors (4). The final pathological assessment of 35 breast specimens identified 5 (14.7%) positive margins. Intraoperative ICG-FI revealed hyperfluorescent signals in 15 (42.9%) patients and an absence of fluorescent signals in 20 (57.1%). Median SBR in patients with involved margins was 1.8 (SD 0.7) and was 1.25 (SD 0.6) in patients with clear margins (p = 0.05). The accuracy, specificity, positive and negative predictive value of ICG-FI for breast surgical margin assessment were 71%, 60%, 29% and 100%, respectively.

CONCLUSION

ICG-FI of BC surgical beds has a high negative predictive value for surgical margin assessment during BCS. The absence of residual fluorescence in the surgical bed of patients with fluorescent tumors predicts negative margins at final pathology and allows the surgeon to avoid further intraoperative analysis.

A radical approach to achieve complete cytoreductive surgery improve survival of patients with advanced ovarian cancer

INTRODUCTION

Cytoreductive surgery of locally advanced ovarian cancer has evolved in the last few years from surgery to remove macroscopic residual disease (<1cm; R2b) to macroscopic complete cytoreductive surgery with no gross residual disease (R1). The aim of this study was to evaluate the impact of the adoption of a maximalist surgical approach on postoperative complications, disease recurrence and survival.

MATERIALS AND METHODS

This was a retrospective study using prospectively collected data on patients who received either conservative approach (CA) or radical approach (RA) surgical treatment for primary ovarian cancer stage IIIc/IVa/IVb between June 2006 and June 2013.

RESULTS

Data for 114 patients were included, 33 patients in the CA group and 68 patients in the RA group were consequently analysed. In the RA group, operative time was longer, in relation to more complex surgical procedures; with more blood losses and a higher rate of compete macroscopic resection. Totally, 77% of the patients had postoperative complications, with more grade I/II complications in the RA group but the same rates of grade III/IV complications in the both groups (P=0.14). For all patient study population, the overall and disease-free survivals were improved in case of no macroscopic residual disease. Overall survival was improved in the RA group (P=0.05), with no difference in terms of disease-free survival (P=0.29) CONCLUSION: A radical approach in advanced ovarian cancer allows a higher rate of complete cytoreductive surgery impacting overall survival. However, a non-significant trend for increased mild complications (grade I/II) rate is observed in this group.

Tumor Banks: A Quality Control Scheme Proposal

Introduction: Tumor banks make a considerable contribution to translational research. Using emerging molecular tests on frozen material facilitates the development of new diagnostic and therapeutic strategies, especially in rare cases. However, standard quality control schemes are lacking in the current literature.

Methods: In 2017, we have conducted a robust quality control test on 100 of 15,000 fresh frozen samples collected between 2000 and 2013 at the Jules Bordet Tumor Bank (Brussels). RNA and DNA extraction was done. The quality of RNA, DNA and proteins were evaluated, respectively by measuring RNA Integrity Number (RIN), by checking Electrophoretic Integrity (EI) and by performing Immunohistochemistry staining (IHC). A score, ranging from poor (1) to excellent (4), was attributed based on technical analysis.

Results: RNA purity was scored 4 in 97% of the cases, 3 in 2%, and 2 in 1%. RIN scores were similarly 4 in 89%, 3 in 10%, and 2 in 1% of the cases. DNA purity was scored 4 in 94% and 3 in 6%, EI was scored 4 in 100% of the cases. Despite morphology loss after freezing, HER2, ER, and Ki67 IHC stainings yielded a score of 4 in the majority of samples. Furthermore, participating in the ISBER Proficiency Testing helped us validate our techniques and the technician's work. Seven processing schemes were carried out, the scores obtained were very satisfactory (20/27) or satisfactory (7/27).

Conclusion: Tumor Banks can be precious for translational research. Nevertheless, firm quality controls should be applied to ensure high quality material delivery. Only then can biobanks contribute to diagnostics, biomarkers discovery and reliable molecular test development.

Total choline quantification measured by 1H MR spectroscopy as early predictor of response after neoadjuvant treatment for locally advanced breast cancer: The impact of immunohistochemical status

BACKGROUND

Validation of new biomarkers is essential for the early evaluation of neoadjuvant treatments.

PURPOSE

To determine whether measurements of total choline (tCho) by 1H spectroscopy could predict morphological or pathological complete response (pCR) of neoadjuvant treatment and whether breast cancer subgroups are related to prediction accuracy.

STUDY TYPE

Prospective, nonrandomized, monocentric, diagnostic study.

POPULATION

Sixty patients were initially included with 39 women participating in the final cohort.

FIELD STRENGTH/SEQUENCE

A 1.5T scanner was used for acquisition and MRS was performed using the syngo GRACE sequence.

ASSESSMENT

MRS and MRI examinations were performed at baseline (TP1), 24-72 hours after first chemotherapy (TP2), after the end of anthracycline treatment (TP3), and MRI only after the end of taxane treatment (TP4). Early (EMR) and late (LMR) morphological response were defined as %ΔDmax13 or %ΔDmax14, respectively. Responders were patients with %ΔDmax >30. Pathological complete response (pCR) patients achieved a residual cancer burden score of 0.

STATISTICAL TESTS

T-test, receiver operating characteristic (ROC) curves, multiple regression, logistic regression, one-way analysis of variance (ANOVA) analysis were used for the analysis.

RESULTS

At TP1 there was a significant difference between response groups for tCho1 concerning EMR prediction (P = 0.05) and pCR (P < 0.05) and for K_ep 1 (P = 0.03) concerning LMR prediction. At TP2, no modification of tCho and other parameters could predict response. At TP3, ΔtCho, ΔDmax, and ΔVol could predict LMR (P < 0.05 for all parameters), pCR (P < 0.05 for all parameters), and ΔK^trans could predict only pCR (P = 0.04). Logistic regression at baseline showed the highest area under the curve (AUC) of 0.9 for prediction of pCR. The triple negative (TN) subgroup showed significantly higher tCho at baseline (P = 0.02) and higher ΔtCho levels at TP3 (P < 0.05).

DATA CONCLUSION

Baseline measurements of tCho in combination with clinicopathological criteria could predict non-pCR with a high AUC. Furthermore, tCho quantification for prediction of pCR was more sensitive for TN tumors.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2018;48:982-993.

ICG-fluorescence imaging for detection of peritoneal metastases and residual tumoral scars in locally advanced ovarian cancer: A pilot study

BACKGROUND AND OBJECTIVES

No intraoperative imaging techniques exist for detecting tumor nodules or tumor scar tissues in patients treated with upfront or interval cytoreductive surgery (CS) after neoadjuvant chemotherapy (NAC). The aims of this study were to evaluate the role of indocyanine green (ICG) fluorescence imaging (FI) for the detection of peritoneal metastases (PM) and evaluate whether it can be used to detect remnant tumor cells in scar tissue.

METHODS

Patients with PM from ovarian cancer admitted for CS were included. ICG, at 0.25 mg per kg of patient weight, was injected intraoperatively after explorative laparotomy before CS.

RESULTS

A total of 108 peritoneal lesions, including 25 scars, were imaged in 20 patients. Seventy-three were malignant (67.6%) and 35 benign (32.4%). The mean Tumor to Background Ratio (ex vivo) was 1.8 (SD 1.3) in malignant and 1.0 (SD 0.79) in benign nodules (P = 0.007). Of 25 post-NAC scars, the mean Tumor to Background Ratio (TBR) (in vivo) was 2.06 (SD 1.15) in malignant and 1.21 (SD 0.50) in benign nodules (P = 0.26). The positive predictive value of ICG-FI to detect tumor cells in scars was 57.1%.

CONCLUSIONS

ICG-FI is accurate to demonstrate PM in ovarian cancer but unable to discriminate between benign and malignant post-NAC.

Conditional hypovascularization and hypoxia in islets do not overtly influence adult β-cell mass or function

It is generally accepted that vascularization and oxygenation of pancreatic islets are essential for the maintenance of an optimal β-cell mass and function and that signaling by vascular endothelial growth factor (VEGF) is crucial for pancreas development, insulin gene expression/secretion, and (compensatory) β-cell proliferation. A novel mouse model was designed to allow conditional production of human sFlt1 by β-cells in order to trap VEGF and study the effect of time-dependent inhibition of VEGF signaling on adult β-cell fate and metabolism. Secretion of sFlt1 by adult β-cells resulted in a rapid regression of blood vessels and hypoxia within the islets. Besides blunted insulin release, β-cells displayed a remarkable capacity for coping with these presumed unfavorable conditions: even after prolonged periods of blood vessel ablation, basal and stimulated blood glucose levels were only slightly increased, while β-cell proliferation and mass remained unaffected. Moreover, ablation of blood vessels did not prevent β-cell generation after severe pancreas injury by partial pancreatic duct ligation or partial pancreatectomy. Our data thus argue against a major role of blood vessels to preserve adult β-cell generation and function, restricting their importance to facilitating rapid and adequate insulin delivery.

Sustained function of alginate-encapsulated human islet cell implants in the peritoneal cavity of mice leading to a pilot study in a type 1 diabetic patient

AIMS/HYPOTHESIS

Alginate-encapsulated human islet cell grafts have not been able to correct diabetes in humans, whereas free grafts have. This study examined in immunodeficient mice whether alginate-encapsulated graft function was inferior to that of free grafts of the same size and composition.

METHODS

Cultured human islet cells were equally distributed over free and alginate-encapsulated grafts before implantation in, respectively, the kidney capsule and the peritoneal cavity of non-obese diabetic mice with severe combined immunodeficiency and alloxan-induced diabetes. Implants were followed for in vivo function and retrieved for analysis of cellular composition (all) and insulin secretory responsiveness (capsules).

RESULTS

Free implants with low beta cell purity (19 ± 1%) were non-functional and underwent 90% beta cell loss. At medium purity (50 ± 1%), they were functional at post-transplant week 1, evolving to normoglycaemia (4/8) or to C-peptide negativity (4/8) depending on the degree of beta cell-specific losses. Encapsulated implants immediately and sustainably corrected diabetes, irrespective of beta cell purity (16/16). Most capsules were retrievable as single units, enriched in endocrine cells that exhibited rapid secretory responses to glucose and glucagon. Single capsules with similar properties were also retrieved from a type 1 diabetic recipient at post-transplant month 3. However, the vast majority were clustered and contained debris, explaining the poor rise in plasma C-peptide.

CONCLUSIONS/INTERPRETATION

In immunodeficient mice, i.p. implanted alginate-encapsulated human islet cells exhibited a better outcome than free implants under the kidney capsule. They did not show primary non-function at low beta cell purity and avoided beta cell-specific losses by rapidly establishing normoglycaemia. Retrieved capsules presented secretory responses to glucose, which was also observed in a type 1 diabetic recipient.

Beta cell count instead of beta cell mass to assess and localize growth in beta cell population following pancreatic duct ligation in mice

Background

Pancreatic-tail duct ligation (PDL) in adult rodents has been reported to induce beta cell generation and increase beta cell mass but increases in beta cell number have not been demonstrated. This study examines whether PDL increases beta cell number and whether this is caused by neogenesis of small clusters and/or their growth to larger aggregates.

Methodology

Total beta cell number and its distribution over small (<50 µm), medium, large (>100 µm) clusters was determined in pancreatic tails of 10-week-old mice, 2 weeks after PDL or sham.

Principal findings

PDL increased total beta cell mass but not total beta cell number. It induced neogenesis of small beta cell clusters (2.2-fold higher number) which contained a higher percent proliferating beta cells (1.9% Ki67+cells) than sham tails (<0.2%); their higher beta cell number represented <5% of total beta cell number and was associated with a similar increase in alpha cell number. It is unknown whether the regenerative process is causally related to the inflammatory infiltration in PDL-tails. Human pancreases with inflammatory infiltration also exhibited activation of proliferation in small beta cell clusters.

Conclusions/significance

The PDL model illustrates the advantage of direct beta cell counts over beta cell mass measurements when assessing and localizing beta cell regeneration in the pancreas. It demonstrates the ability of the adult mouse pancreas for neogenesis of small beta cell clusters with activated beta cell proliferation. Further studies should investigate conditions under which neoformed small beta cell clusters grow to larger aggregates and hence to higher total beta cell numbers.

Pdx1- and Ngn3-Cre-mediated PLAG1 expression in the pancreas leads to endocrine hormone imbalances that affect glucose metabolism

Pleomorphic adenoma gene-like 1 (PLAGL1) has been linked to transient neonatal diabetes mellitus. Here, we investigated the role of the related pleomorphic adenoma gene 1 (PLAG1) in glucose homeostasis. PLAG1 transgenic mice in which expression of the PLAG1 transgene can be targeted to different organs by Cre-mediated modulation were crossed with Pdx1-Cre or Ngn3-Cre mice, resulting in double transgenic P1-Pdx1Cre or P1-Ngn3Cre mice, respectively. P1-Pdx1Cre and P1-Ngn3Cre mice developed hyperplasia of pancreatic islets due to increased β- and δ- but not α-cell proliferation. In young P1-Pdx1Cre mice (less than 15 weeks) there was a balanced increase in the pancreatic content of insulin and somatostatin, which was associated with normoglycemia. In older P1-Pdx1Cre mice the pancreatic somatostatin content far exceeded that of insulin, leading to the progressive development of severe hypoglycemia beyond 30 weeks. In contrast, in older P1-Ngn3Cre mice the relative increase of the pancreatic insulin content exceeded that of somatostatin and these mice remained normoglycemic. In conclusion, forced expression of PLAG1 under the control of the Pdx1 or Ngn3 promoter in murine pancreas induces different degrees of endocrine hormone imbalances within the pancreas, which is associated with hypoglycemia in P1-Pdx1Cre mice but not P1-Ngn3Cre mice. These results suggest that once stem cell-derived islet transplantations become possible, the appropriate balance between different hormone-producing cells will need to be preserved to prevent deregulated glucose metabolism.

Contribution of postnatally formed small beta cell aggregates to functional beta cell mass in adult rat pancreas

AIMS/HYPOTHESIS

Neogenesis of beta cells and their clustering to small aggregates is a key process in prenatal development of beta cell mass. We investigated the contribution of postnatally formed small aggregates to functional beta cell mass in adult rats.

METHODS

Conditions were defined for (1) counting total beta cell number in pancreases with relative error of <10% and (2) determining their distribution over aggregates of different size and over functionally different subpopulations.

RESULTS

Pancreases of 10-week-old male Wistar rats contained 2.8 ± 0.2 × 10⁶ beta cells, of which >90% was generated postnatally, involving: (1) neo-formation of 30,000 aggregates with diameter <50 μm including single cells; and (2) growth of 5,500 aggregates to larger sizes, accounting for 90% of the increase in cell number, with number of growing aggregates in the tail 50% greater than elsewhere. At 10 weeks, 86% of aggregates were <50 μm; compared with aggregates >200 μm, their beta cells exhibited a higher basal insulin content that was also resistant to glibenclamide-induced degranulation. The pool of Ki67-positive beta cells was sixfold larger than at birth and distributed over all aggregate sizes.

CONCLUSIONS/INTERPRETATION

We describe a method for in situ counting of beta cell numbers and subpopulations with low relative error. In adult rats, >90% of beta cells and beta cell aggregates are formed after birth. Aggregates <50 μm are more than 100-fold more abundant than aggregates >200 μm, which are selected for isolated islet studies. Their topographic and functional properties contribute to the functional heterogeneity of the beta cell population; their growth to larger aggregates with characteristic beta cell functions may serve future metabolic needs.

Ectopic expression of E2F1 stimulates beta-cell proliferation and function

OBJECTIVE

Generating functional beta-cells by inducing their proliferation may provide new perspectives for cell therapy in diabetes. Transcription factor E2F1 controls G(1)- to S-phase transition during the cycling of many cell types and is required for pancreatic beta-cell growth and function. However, the consequences of overexpression of E2F1 in beta-cells are unknown.

RESEARCH DESIGN AND METHODS

The effects of E2F1 overexpression on beta-cell proliferation and function were analyzed in isolated rat beta-cells and in transgenic mice.

RESULTS

Adenovirus AdE2F1-mediated overexpression of E2F1 increased the proliferation of isolated primary rat beta-cells 20-fold but also enhanced beta-cell death. Coinfection with adenovirus AdAkt expressing a constitutively active form of Akt (protein kinase B) suppressed beta-cell death to control levels. At 48 h after infection, the total beta-cell number and insulin content were, respectively, 46 and 79% higher in AdE2F1+AdAkt-infected cultures compared with untreated. Conditional overexpression of E2F1 in mice resulted in a twofold increase of beta-cell proliferation and a 70% increase of pancreatic insulin content, but did not increase beta-cell mass. Glucose-challenged insulin release was increased, and the mice showed protection against toxin-induced diabetes.

CONCLUSIONS

Overexpression of E2F1, either in vitro or in vivo, can stimulate beta-cell proliferation activity. In vivo E2F1 expression significantly increases the insulin content and function of adult beta-cells, making it a strategic target for therapeutic manipulation of beta-cell function.

Restoring a functional beta-cell mass in diabetes

Type 1 and type 2 diabetes have often been presented as disease forms that profoundly differ in the presence and pathogenic significance of a reduced beta-cell mass. We review evidence indicating that the beta-cell mass in type 1 diabetes is usually not decreased by at least 90% at clinical onset, and remains often detectable for years after diagnosis at age above 15 years. Clinical and experimental evidence also exists for a reduced beta-cell mass in type 2 diabetes where it can be the cause for and/or the consequence of dysregulated beta-cell functions. With beta-cell mass defined as number of beta-cells, these views face the limitation of insufficient data and methods for human organs. Because beta-cells can occur under different phenotypes that vary with age and with environmental conditions, we propose to use the term functional beta-cell mass as an assessment of a beta-cell population by the number of beta-cells and their phenotype or functional state. Assays exist to measure functional beta-cell mass in isolated preparations. We selected a glucose-clamp test to evaluate functional beta-cell mass in type 1 patients at clinical onset and in type 1 recipients following intraportal islet cell transplantation. Comparison of the data with those in non-diabetic controls helps targeting and monitoring of therapeutic interventions.