Therapeutic potential of Mesenchymal Stem Cells for the treatment of diabetic peripheral neuropathy

Type-1 Diabetes is generally treated with exogenous insulin administration. Despite treatment, a very common long term consequence of diabetes is the development of a disabling and painful peripheral neuropathy. The transplantation of pancreatic islets is an advanced alternative therapeutic approach, but its clinical application is still very limited, mainly because of the great number of islets required to complete the procedure and of their short-term survival. An intriguing method to improve the performance of pancreatic islets transplantation is the co-transplantation of Mesenchymal Stem Cells (MSCs), adult stem cells already known to support the survival of different cellular populations. In this proof-of-concept study, we demonstrated using an in vivo model of diabetes, the ability of allogenic MSCs to reduce the number of pancreatic islets necessary to achieve glycemic control in diabetic rats, and overall their positive effect on diabetic neuropathy, with the reduction of all the neuropathic signs showed after disease induction. The cutback of the pancreatic islet number required to control glycemia and the regression of the painful neuropathy make MSC co-transplantation a very promising tool to improve the clinical feasibility of pancreatic islet transplantation for diabetes treatment.

Stem cell augmented mesh materials: an in vitro and in vivo study

INTRODUCTION AND HYPOTHESIS

To test in vitro and in vivo the capability of mesh materials to act as scaffolds for rat-derived mesenchymal stem cells (rMSCs) and to compare inflammatory response and collagen characteristics of implant materials, either seeded or not with rMSCs.

METHODS

rMSCs isolated from rat bone marrow were seeded and cultured in vitro on four different implant materials. Implants showing the best rMSC proliferation rate were selected for the in vivo experiment. Forty-eight adult female Sprague-Dawley rats were randomly divided into two treatment groups. The implant of interest-either seeded or not with rMSCs-was laid and fixed over the muscular abdominal wall. Main outcome measures were: in vitro, proliferation of rMSCs on selected materials; in vivo, the occurrence of topical complications, the evaluation of systemic and local inflammatory response and examination of the biomechanical properties of explants.

RESULTS

Surgisis and Pelvitex displayed the best cell growth in vitro. At 90 days in the rat model, rMSCs were related to a lower count of neutrophil cells for Pelvitex and a greater organisation and collagen amount for Surgisis. At 7 days Surgisis samples seeded with rMSCs displayed higher breaking force and stiffness.

CONCLUSIONS

The presence of rMSCs reduced the systemic inflammatory response on synthetic implants and improved collagen characteristics at the interface between biological grafts and native tissues. rMSCs enhanced the stripping force on biological explants.

A novel AMPK activator reduces glucose uptake and inhibits tumor progression in a mouse xenograft model of colorectal cancer

The anticancer activity of a novel pure 1,4-Diaryl-2-azetidinone (1), endowed with a higher solubility than the well known Combretastatin A4, is tested in mice. We previously reported that Compound (1) showed specific antiproliferative activity against duodenal and colon cancer cells, inducing activation of AMP-activated protein kinase and apoptosis. Here we estimate that the maximum tolerated dose in a mouse model is 40 mg/kg; the drug is well tolerated both in single dose and in repeated administration schedules. The drug displays a significant antitumor activity and a tumor growth delay when administered at the MTD both in single and fractionated i.v. administration in a mouse xenograft model of colorectal cancer. Arrest of tumor growth and relapse after drug suspension are parallel to modification in glucose demand as shown by PET studies with [(18)F] FDG. These data strongly support Compound (1) as a promising molecule for in vivo treatment of colorectal cancer.

CR4056, a new analgesic I2 ligand, is highly effective against bortezomib-induced painful neuropathy in rats

Although bortezomib (BTZ) is the frontline treatment for multiple myeloma, its clinical use is limited by the occurrence of painful peripheral neuropathy, whose treatment is still an unmet clinical need. Previous studies have shown chronic BTZ administration (0.20 mg/kg intravenously three times a week for 8 weeks) to female Wistar rats induced a peripheral neuropathy similar to that observed in humans. In this animal model of BTZ-induced neurotoxicity, the present authors evaluated the efficacy of CR4056, a novel I2 ligand endowed with a remarkable efficacy in several animal pain models. CR4056 was administered in a wide range of doses (0.6-60 mg/kg by gavage every day for 2-3 weeks) in comparison with buprenorphine (Bupre) (28.8 μg/kg subcutaneously every day for 2 weeks) and gabapentin (Gaba) (100 mg/kg by gavage every day for 3 weeks). Chronic administration of BTZ reduced nerve conduction velocity and induced allodynia. CR4056, Bupre, or Gaba did not affect the impaired nerve conduction velocity. Conversely, CR4056 dose-dependently reversed BTZ-induced allodynia (minimum effective dose 0.6 mg/kg). The optimal dose found, 6 mg/kg, provided a constant pain relief throughout the treatment period and without rebound after suspension, being effective when coadministered with BTZ, starting before or after allodynia was established, or when administered alone after BTZ cessation. A certain degree of tolerance was seen after 7 days of administration, but only at the highest doses (20 and 60 mg/kg). Bupre was effective only acutely, since tolerance was evident from the fourth day onwards. Gaba showed a significant activity only at the fourth day of treatment. CR4056, over the range of concentrations of 3-30 μM, was unable to hinder BTZ cytotoxicity on several tumor cell lines, which could indicate that this substance does not directly interfere with BTZ antitumor activity. Therefore, CR4056 could represent a new treatment option for BTZ-induced neuropathic pain.

In vivo comparative study of the cytotoxicity of a liposomal formulation of cisplatin (lipoplatin™)

PURPOSE

Cisplatin is one of the most effective cytotoxic agents in the treatment of solid malignancies, but its use is limited by several side effects. Among them, peripheral neurotoxicity can be dose limiting. A liposomal formulation of cisplatin, Lipoplatin™, was developed to reduce the systemic toxicity of cisplatin but without preventing its efficacy. The aim of this study was to use an animal model to establish, through a multimodal approach, whether chronic treatment with two different schedules of Lipoplatin™, selected within the range of its anticancer effective dose, is less neurotoxic than cisplatin administration.

METHODS

Female Wistar rats were treated intraperitoneally with cisplatin at a dose of 4 mg/kg or with Lipoplatin™ at doses delivering 12 or 24 mg/kg of cisplatin once weekly for 4 weeks. General toxicity was assessed by daily observation, body weight change, hematological and blood chemistry analysis, and histopathology of liver and kidney. The onset of peripheral neurotoxicity was assessed by measuring tail nerve conduction velocity (NCV), morphological and morphometric analysis of dorsal root ganglia (DRG), and morphological analysis of the sciatic nerve.

RESULTS

Cisplatin induced a statistically significant reduction in body weight, the development of renal failure, and impairment in NCV with pathological alterations in the DRG and sciatic nerve. By contrast, Lipoplatin™ was markedly less nephrotoxic, and no significant weight gain reduction was observed in animals treated with both doses of the drug. Moreover, the lowest dose induced less severe damage to the peripheral nervous system with a moderate decrease in NCV and mild pathological alterations in DRG and the sciatic nerve.

CONCLUSIONS

The results suggest that Lipoplatin™ 12 mg/kg is less neurotoxic than cisplatin 4 mg/kg, thus opening up the possibility of using this new formulation in future studies where its anticancer activity and the peripheral neurotoxicity will be assessed in parallel.

Regression of diabetic complications by islet transplantation in the rat

AIMS/HYPOTHESIS

Type 1 diabetes is a chronic disease leading to complications such as peripheral neuropathies, nephropathy and cardiovascular disease. Pancreatic islet transplantation is being extensively investigated for blood glucose control in animals and in human type 1 diabetic patients, but the question of whether it can reverse long-term diabetic complications has not been fully explored. We investigated the effects of islet transplantation on diabetic complications in a rat model of streptozotocin-induced diabetes.

METHODS

Three groups of rats were used: healthy controls, diabetic and diabetic rats transplanted with microencapsulated islets at 2 months after diabetes induction, when neuropathy was detectable by a decrease in tail nerve conduction velocity (NCV) and impaired nociceptive thresholds. Blood glucose levels and body weight were measured weekly. The variables considered were: thermal (hot plate test) and mechanical sensitivity (Randal-Selitto paw withdrawal test), NCV and Na+, K+-ATPase activity in the sciatic nerve. At the end of the experiments hearts were removed for morphometric determination and myocyte number, and kidneys removed for histological examination.

RESULTS

Islet transplantation in diabetic rats induced normoglycaemia in a few days, accompanied by a rapid rise in body weight and amelioration of impaired nociceptive thresholds, as well as normalisation of NCV and Na(+), K(+)-ATPase, which were both about 25% below normal in diabetic rats. Myocyte loss was reduced (-34%) by islet transplantation and the observed mild kidney damage of diabetic rats was prevented.

CONCLUSIONS/INTERPRETATION

Besides controlling glycaemia, transplantation of microencapsulated pancreatic islets induced almost complete regression of neuropathy and prevented cardiovascular alterations.