Multimodal Comparison of Diabetic Neuropathy in Aged Streptozotocin-Treated Sprague-Dawley and Zucker Diabetic Fatty Rats.

The development and progression of diabetic polyneuropathy (DPN) are due to multiple mechanisms. The creation of reliable animal models of DPN has been challenging and this issue has not yet been solved. However, despite some recognized differences from humans, most of the current knowledge on the pathogenesis of DPN relies on results achieved using rodent animal models. The simplest experimental DPN model reproduces type 1 diabetes, induced by massive chemical destruction of pancreatic beta cells with streptozotocin (STZ). Spontaneous/transgenic models of diabetes are less frequently used, mostly because they are less predictable in clinical course, more expensive, and require a variable time to achieve homogeneous metabolic conditions. Among them, Zucker diabetic fatty (ZDF) rats represent a typical type 2 diabetes model. Both STZ-induced and ZDF rats have been extensively used, but only very few studies have compared the long-term similarities and differences existing between these two models. Moreover, inconsistencies have been reported regarding several aspects of short-term in vivo studies using these models. In this study, we compared the long-term course of DPN in STZ-treated Sprague-Dawley and ZDF rats with a multimodal set of readout measures.

Comparison of 5-year progression of retinitis pigmentosa involving the posterior pole among siblings by means of SD-OCT: a retrospective study.

BACKGROUND: The aim of this study is to analyze and compare the progression of photoreceptor atrophy among siblings affected by retinitis pigmentosa by means of spectral SD-OCT. METHODS: Fifty three eyes of 27 patients belonging to 12 family clusters were analyzed. To assess the annual progression rate of photoreceptor atrophy, the ellipsoid zone (EZ) line was measured in OCT sections through the fovea. We used multivariate generalized mixed effects to model the rate of progression and its relation to the initial ellipsoid zone line width. RESULTS: During our 4.84 years (± 1.44) mean follow up time (range 3-7) 53 eyes were examined. The ellipsoid zone line width declined with a yearly average rate of 76.4 µm (4.16% / year) (p-value < 0.0001). Progression rates were poorly correlated within family clusters (p-value = 0.23) and showed statistical difference between affected siblings (p-value = 0.007). There was no correlation between inter-familiar progression rate and mode of inheritance (p-value = 0.98) as well as between age and ellipsoid zone line width among siblings (p-value = 0.91). CONCLUSION: RP could be extremely heterogeneous even among siblings: an accurate and sensitive method to follow the progression of the disease is fundamental for future development of clinical trials and therapy strategies.

Evaluation of tubulin polymerization and chronic inhibition of proteasome as citotoxicity mechanisms in bortezomib-induced peripheral neuropathy.

Bortezomib (BTZ) is the first proteasome inhibitor entered in clinical practice. Peripheral neuropathy is likely to be a class side effect of these drugs, although its severity is largely variable, and it deserves to be further investigated, since the mechanisms of BTZ-induced peripheral neurotoxicity (BiPN) are still unknown.   In our study, we investigated in vivo and in vitro possible pathogenic events relevant to BiPN using a well-established rat model, with particular reference to the extent of proteasome inhibition and the effects on α-tubulin polymerization in sciatic nerves and dorsal root ganglia specimens obtained from animals treated with chronic regimens at a dose of 0.2 mg/kg intravenously. The same assessments were also performed after a single injection. Moreover, these studies were replicated in vitro using embryonic DRG neurons exposed to 100 nM BTZ and adult DRG neurons exposed to 10-50 nM BTZ for 24 h and 48 h. A significant increase in the polymerized fraction of α-tubulin and prolonged proteasome inhibition were observed after the chronic BTZ treatment in vivo. Recovery to physiological levels was observed after a 4-week follow-up post-treatment period. Proteasome inhibition and increased α-tubulin polymerization were also observed following BTZ treatment of both embryonic and adult DRG neurons in vitro. Our in vivo results suggest that proteasome inhibition and alteration of tubulin dynamics contribute to BiPN. The in vitro systems here described reliably replicate the in vivo results, and might therefore be used for further mechanistic studies on the effects of proteasome inhibitors on neurons.

Antibody against tumor necrosis factor-α reduces bortezomib-induced allodynia in a rat model.

BACKGROUND: Bortezomib is an anti-neoplastic drug acting against multiple myeloma but its use is associated with the onset of painful peripheral neuropathy. Tumor necrosis factor-α (TNFα) is associated with the development of neuropathic pain; several models have shown that the inactivation of TNFα leads to a reduction in pain stimuli perception. The aim of the present study was to analyze if the administration of an antibody against TNFα is able to prevent the development of bortezomib-induced neuropathic pain. MATERIALS AND METHODS: Nerve conduction velocity was measured and a histopathological examination was performed to assess the extent of peripheral neuropathy. To study the onset of painful neuropathy, the response to mechanical or thermal stimuli was evaluated. RESULTS: This study demonstrated that co-administration of an antibody against TNFα is able to prevent allodynia induced by bortezomib but does not reduce neuropathy. CONCLUSION: Targeting TNFα might be useful in limiting patients' discomfort during bortezomib therapy.

Islet transplantation and insulin administration relieve long-term complications and rescue the residual endogenous pancreatic ß cells.

Islet transplantation is a poorly investigated long-term strategy for insulin replacement and for treatment of complications in patients with diabetes. We investigated whether islet transplantation and insulin treatment can relieve diabetic neuropathy and rescue the residual endogenous pancreatic ß cells. We used a multimodal approach, with five groups of Sprague-Dawley rats studied for 8 months: control rats, diabetic rats, insulin-treated diabetic rats with moderate or mild hyperglycemia, and diabetic rats transplanted with microencapsulated islets. Islet transplantation normalized glycemia and increased body and muscle weight; it was also effective in reducing proteinuria and altered liver function. Transplantation significantly improved tail nerve conduction velocity, Na(+)-K(+)-ATPase activity, and morphological alterations in the sciatic nerve as evidenced by decrease in g-ratio; it also restored thermal and ameliorated mechanical nociceptive thresholds. Morphometric analysis of pancreas indicated a significant ß-cell volume increase in transplanted rats, compared with mildly and moderately hyperglycemic rats. Thus, allogeneic islet transplantation had a positive systemic effect in diabetic rats and induced regression of the established neuropathy and restitution of the typical characteristics of the islets. These findings strongly reinforce the need for improving glycemic control, not only to reverse established diabetic complications but also to improve ß-cell status in diabetic pancreas.

Bortezomib-induced painful peripheral neuropathy: an electrophysiological, behavioral, morphological and mechanistic study in the mouse.

Bortezomib is the first proteasome inhibitor with significant antineoplastic activity for the treatment of relapsed/refractory multiple myeloma as well as other hematological and solid neoplasms. Peripheral neurological complications manifesting with paresthesias, burning sensations, dysesthesias, numbness, sensory loss, reduced proprioception and vibratory sensitivity are among the major limiting side effects associated with bortezomib therapy. Although bortezomib-induced painful peripheral neuropathy is clinically easy to diagnose and reliable models are available, its pathophysiology remains partly unclear. In this study we used well-characterized immune-competent and immune-compromised mouse models of bortezomib-induced painful peripheral neuropathy. To characterize the drug-induced pathological changes in the peripheral nervous system, we examined the involvement of spinal cord neuronal function in the development of neuropathic pain and investigated the relevance of the immune response in painful peripheral neuropathy induced by bortezomib. We found that bortezomib treatment induced morphological changes in the spinal cord, dorsal roots, dorsal root ganglia (DRG) and peripheral nerves. Neurophysiological abnormalities and specific functional alterations in Aδ and C fibers were also observed in peripheral nerve fibers. Mice developed mechanical allodynia and functional abnormalities of wide dynamic range neurons in the dorsal horn of spinal cord. Bortezomib induced increased expression of the neuronal stress marker activating transcription factor-3 in most DRG. Moreover, the immunodeficient animals treated with bortezomib developed a painful peripheral neuropathy with the same features observed in the immunocompetent mice. In conclusion, this study extends the knowledge of the sites of damage induced in the nervous system by bortezomib administration. Moreover, a selective functional vulnerability of peripheral nerve fiber subpopulations was found as well as a change in the electrical activity of wide dynamic range neurons of dorsal horn of spinal cord. Finally, the immune response is not a key factor in the development of morphological and functional damage induced by bortezomib in the peripheral nervous system.

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.

'Possessed': acute confusional migraine in an adolescent, prevented by topiramate.

Acute confusional migraine (ACM) is recognized as a rare, but highly disabling migraine equivalent, mostly reported in children and adolescents. Herein we describe the case of a 12-year-old girl admitted to hospital for an acute confusional state and severe psychomotor agitation, associated with a pulsating headache and nausea, which turned out to be a manifestation of ACM. The girl was discharged on topiramate prophylaxis, titrated up to 75 mg/die; no recurrence of confusional and/or headache episodes has been reported over the last 14 months to date. Due to the rarity of this clinical entity, only anecdotal reports about acute and prophylactic treatment of ACM are available in the literature. The case reported herein suggests that topiramate seems to be effective in ACM prophylaxis, although a longer observation period in our patient and more cases are needed to confirm any long-term clinical benefit.

Exposure-response relationship of the synthetic epothilone sagopilone in a peripheral neurotoxicity rat model.

Since peripheral sensory neuropathy is the major, clinically relevant side effect of sagopilone we investigated the general and peripheral neurotoxicity of sagopilone administered intravenously with different doses (1.2 and 2.4 mg/kg) and schedules in 48 Wistar rats and we performed in parallel a pharmacokinetic/pharmacodynamic (PK/PD) study. A trend toward a different peripheral neurotoxicity could be assessed after 2 weeks of treatment (bolus > 30-min infusion > 3-h infusion) with both doses of sagopilone. Although sagopilone concentrations in peripheral nerve tissue above 100 ng/g were associated with a reduction in nerve conduction velocity (NCV), a clear dose-dependence of this reduction on the level of systemic exposure to sagopilone was not observed. The PK/PD evaluation revealed no consistent effect of the infusion duration on serum PK parameters or the PD read-out NCV. Sagopilone concentrations in brain, sciatic nerve, liver, and kidney were higher after bolus compared to infusion, but there were no influence of infusion duration on these concentrations. No correlation between sagopilone concentrations in any organ/tissue with NCV changes was detected. This study evidences that the PD of sagopilone is not the main determinant of the onset and severity of sagopilone-induced peripheral neurotoxicity in the investigated clinically-relevant dose range, thus indicating that further investigation might identify neuronal-specific mechanisms of action able to drive a focused strategy to prevent peripheral neurotoxicity without reducing the anticancer effectiveness of the epothilones.

[The biliointestinal bypass: a thirty-years experience]. / Il bypass bilio-intestinale. Un'esperienza italiana trentennale.

AIM: Aim of our study was the evaluation of Italian experience with bilio-intestinal bypass in the surgical treatment of morbid obesity. MATERIALS AND METHODS: 1030 patients; mean age 36.1 years; preoperative mean weight Kg 136.7; mean preoperative BMI 48.9 kg/m2; mean follow-up 68 years (1-28). 838 patients underwent open and 192 laparoscopic bilio-intestinal bypass. The laparoscopy operation was performed with five lap ports. Section of the jejunum 30 cm from the Treitz was made by linear stapler. The cholecysto-jejunal anastomosis was completed with 45 mm linear stapler. A side-to-side anastomosis between the proximal jejunum and the last 12-18 cm of the ileum was created by firing a 60 mm linear stapler. RESULTS: Weight loss was satisfactory in 93% of operated patients. Comorbidities (arterial hypertension, diabetes, sleep apnea syndrome) solved in majority of the patients. The main late complications were incisional hernia in open technique and oxalic nephrolithiasis. The reversal rate was 2.5%. CONCLUSION: Our experience showed that bilio-intestinal bypass can obtain good results. Using laparoscopic technique it is possible to reduce pain, in-hospital time, respiratory and thromboembolic complications, convalescence and incisional hernia.

Efeitos do tratamento com Agaricus sylvaticus sobre a anemia e os níveis de proteínas C reativa em animais com tumor de Walker 256

Introdução: Os cogumelos medicinais apresentam propriedades farmacológicas e nutricionais que atuam na melhora do bem-estar e no aumento da sobrevida do paciente.(AU)

Efeitos do tratamento com Agaricus sylvaticus sobre a anemia e os níveis de proteína C reativa em animais com tumor sólido de Walker 256 / Effects of Agaricus sylvaticus treatment on anemia and C reactive protein levels in animals with Walker 256 tumor

Introdução: Os cogumelos medicinais apresentam propriedades farmacológicas e nutricionais que atuam na melhora do bem-estar e no aumento da sobrevida do paciente. Objetivos: Avaliar os efeitos do extrato de Agaricus sylvaticus sobre a anemia e os níveis de proteína C reativa em ratos inoculados com tumor sólido de Walker 256. Métodos: 30 ratos Wistar adultos machos foram distribuídos em dois grupos (n igual a 15 cada) para suplementação dietética distinta (Agaricus sylvaticus e placebo) administrada de 12 em 12 horas. Os animais foram sacrificados no 13º dia e foi coletado sangue para análise laboratorial. Os testes estatísticos foram realizados através da análise estatística univariada (ANOVA), com significância para p menor ou igual a 0,05. Resultados: O grupo tratado com Agaricus sylvaticus apresentou nível de proteína C reativa (PCR) de 0,48 mais ou menos 0,12 mg/dL enquanto o grupo tratado com placebo apresentou o valor de 0,61 mais ou menos a 0,11 mg/dL (p igual a 0,008). O grupo tratado com A. sylvaticus apresentou em média: hemácias 4,53x106 mais ou menos1,15x106/mm³, Hemoglobina (Hb) 8,10 mais ou menos 2,08g/dL, Hematócrito (Ht) 24,02 mais ou menos 4,51 por cento, Hemoglobina Corpuscular Média (HCM) 22,20 mais ou menos 2,4pg, Concentração de Hemoglobina Corpuscular (CHCM) 36,21mais ou menos 6,38 por cento e Volume corpuscular médio (VCM) 62,46 mais ou menos 6,74fl. No grupo tratado com placebo foram encontrados: hemácias 3,33x106 mais ou menos 0,86x106/mm³, Hb 6,96 mais ou menos 1,55g/dL, Ht 19,7 mais ou menos 5,31 por cento, HCM 21,26 mais ou menos 1,31pg, CHCM 29,92 mais ou menos 8,6 por cento e VCM 63,12 mais ou menos 10,19fl. Diferenças significativas foram encontradas para o número de hemácias sendo p igual a 0,004 e hematócrito sendo p igual a 0,03. Conclusão: A redução do nível de Proteína C Reativa e a melhora do quadro anêmico são indicativos de melhor prognóstico para os animais com câncer tratados com o cogumelo Agaricus sylvaticus.

The bilio-intestinal bypass.

BACKGROUND: Since 1990 we adopted the bilio-intestinal bypass (BIBP) for all morbid obese patients eligible to a malabsorption procedure. Since 2001 we used laparoscopic technique. MATERIALS AND METHODS: 102 patients; mean age 35.4 (18-54) years; preoperative mean weight Kg 148.3 (105-225); mean preoperative BMI 54.1 kg/m2 (40-66.2); mean follow-up 10 years (1-22). 83 patients underwent open and 19 laparoscopic BIBP. The operation was performed with five lap ports. Section of the jejunum 30 cm from the Treitz and of mesentery was made by linear stapler. The cholecysto-jejunal anastomosis was completed with 45 mm linear stapler. A side-to-side anastomosis between the proximal jejunum and the last 12-18 cm of the ileum was created by firing a 60 mm linear stapler. On the excluded ileum an anti-reflux valve system was hand-sutured. RESULTS: Five years post-operatively mean weight was 89 (62-130) kg, mean BMI was 31 (24-41) kg/m2. Two patients of the 19 laparoscopic patients were converted in open surgery for adhesions post-appendectomy. The main late complications were incisional hernia (19.3%) and abdominal bloating (2.9%). The reversal and conversion rate was 65%. There was no death. CONCLUSION: Our experience showed that five years post-BIBP the weight loss was satisfactory in 90.7% of patients. Using laparoscopic technique it is possible to reduce pain, in-hospital time, respiratory and thromboembolic complications, convalescence and incisional hernia.