Efficacy of VEGFR-TKIs plus immune checkpoint inhibitors in metastatic renal cell carcinoma patients with favorable IMDC prognosis.

BACKGROUND: Combinations of PD-1/PD-L1 immune checkpoint inhibitors (ICI) with VEGFR-TKIs as first-line therapy significantly improve outcomes of metastatic renal cell carcinoma (mRCC) patients. The benefit of these combinations is well evident in the IMDC intermediate- and poor-risk population, but remains unclear in the subgroup of patients with favorable prognosis. Our meta-analysis aims at evaluating whether the addition of ICIs to VEGFR-TKIs is able to improve the outcome compared to VEGFR-TKIs alone in mRCC patients with favorable prognosis. METHODS: This meta-analysis searched MEDLINE/PubMed, the Cochrane Library and ASCO Meeting abstracts for randomized clinical trials (RCTs) testing the combination of VEGFR-TKI + ICI in mRCC. Data extraction was conducted according to the PRISMA statement. Summary hazard ratio (HR) was calculated using random- or fixed-effects models, depending on studies heterogeneity. RESULTS: Four RCTs were selected. VEGFR-TKI + ICI combinations improved PFS compared to sunitinib (fixed-effect, HR = 0.63; p < 0.00001). However, VEGFR-TKI + ICI combinations did not significantly prolong OS (fixed-effect; HR = 0.99; 95% CI 0.74-1.33; p = 0.95). CONCLUSION: VEGFR-TKI + ICI combinations improved PFS but not OS as first-line therapy for mRCC patients with favorable IMDC prognosis. Longer follow-up and further studies will increase the power of our analysis, suggesting the best first-line therapy for mRCC patients with favorable prognosis.

Comparison of epi-GM3 with GM3 and GM1 as stimulators of neurite outgrowth.

A variety of naturally occurring ganglioside structures were previously shown to be effective agents for inducing neurite outgrowth of primary neurons and neuroblastoma lines. We report here the results of similar experiments with a synthetic epimer of GM3 (epi-GM3) possessing a neuraminidase-resistant beta-ketosidic linkage. This substance was found to enhance neuritogenesis toward two transformed cell lines (neuro-2A, PC-12) and one primary neuronal tissue (dorsal root ganglia). The results indicate that the stereochemistry of the ketoside linkage is not critical and that metabolism of exogenous ganglioside by the treated cells is not involved directly in the neuritogenic phenomenon.

Derivatives of ganglioside GM1 as neuronotrophic agents: comparison of in vivo and in vitro effects.

Exogenously administered gangliosides have been shown to behave as neuronotrophic/neuritogenic agents in a variety of cell culture systems and animal models, but it is not known whether they operate by the same mechanism in vivo and in vitro. To probe this question we have employed two derivatives of GM1 lacking the negative charge: the methyl ester (GM1-CH3) and the NaBH4 reduction product of the latter (GM1-OH) in which the carboxyl group is replaced by a primary alcohol. Both derivatives proved to be as neuritogenic as GM1 in 3 cell culture systems: neuro-2A cels, PC12 cells and explanted dorsal root ganglia. However, GM1-OH proved ineffective when applied to two animal models involving reduction of cholinergic markers in: (a) hippocampus following lesion of the lateral fimbria and (b) nucleus basalis magnocellularis following cortical lesion; GM1-CH3 showed marginal activity in (a) but more in (b), possibly owing to slow hydrolysis to GM1 which was highly active in both animal models. These results indicate the necessity of a negative change on the ganglioside molecule for in vivo but not in vitro activity and point to different mechanisms for the trophic effects of exogenous gangliosides.

Stimulation of neurite outgrowth in vitro by a glycero-ganglioside.

A glycerol-containing analog of ganglioside, with sialic acid attached to a diglyceride-like structure possessing two ether-linked alkyl chains, was prepared synthetically and applied exogenously to three culture systems; neuro-2A neuroblastoma cells, PC12 cells and dorsal root ganglia. This resulted in pronounced stimulation of neurite outgrowth in all three, demonstrating that sialo-lipids(s) lacking ceramide and possessing sialic acid as the sole carbohydrate are able to promote neuritogenesis in approximately the same manner as naturally occurring gangliosides.

Onset and pre-onset studies to define the Huntington's disease natural history.

Huntington's disease's (HD) clinical history has not been defined yet. However, many aspects of the most confusing clinical stages, i.e., the first and last disease phases, including the symptom progression and the disease duration, have been better approached after discovery of the responsible gene. The existence of accurate genetic tests, available for affected and pre-symptomatic subjects (i.e., mutation carriers) and the possibility to study transgenic in vivo models, are actually helping us to understand some of the aspects of HD clinical presentation. HD may present with motor symptoms other than chorea, the psychiatric manifestations may represent part of the clinical picture and cognitive deterioration may occur very early in the disease and depend on early cortical involvement. Pre-onset studies are of crucial importance in understanding the temporal sequence of the clinical events. This is also very important for future therapeutic strategies in those diseases initiating late in the life, such as HD.

Gangliosides as neurotrophic agents: studies on the mechanism of action.

During the normal course of neuronal differentiation gangliosides undergo marked changes in both quantity and quality. These changes, i.e. several-fold increase in concentration and appearance of the gangliotetraose family, have been observed both in vivo and in neuronal cell cultures. In addition to these naturally occurring (endogenous) manifestations, exogenously administered gangliosides have been observed to exert neuritogenic and/or neuronotrophic effects on a variety of neuroblastoma cell lines and primary neuronal culture systems. Unlike the endogenous effects, which appear to require gangliotetraose structures, the structural specificity of the exogenous effect is quite broad. Thus, all of 11 different gangliosides proved neuritogenic with neuro-2A neuroblastoma cells. Furthermore, synthetic sialoglycolipids possessing a beta-ketosidic sialic acid linkage and/or a glyceride-like moiety in place of ceramide all caused enhanced neurite outgrowth in neuro-2A, PC12, and embryonic chick dorsal root ganglia. A derivative of GM1 lacking the negative charge was also active in the same 3 systems. These results point to general perturbation of the membrane, probably a physical-chemical effect, in a manner which triggers intracellular events leading to differentiation. In contrast to these in vitro results, use of the above GM1 derivative in two in vivo models proved ineffective in maintaining the level of cholinergic markers that were preserved by GM1 in lesioned brains. These results point to fundamentally different mechanism for the trophic effects of administered gangliosides in vivo and in vitro.

De novo seven extra repeat expanded mutation in the PRNP gene in an Italian patient with early onset dementia.

Point and octapeptide repeat (24 bp) insertional mutations in the prion protein gene (PRNP) cause a dominantly transmitted dementia, associated with spongiform degeneration of the brain, astrocytic gliosis and neuronal loss due to cell accumulation of mutated protease resistant prion protein. The octapeptide repeat region lies between codon 51 and 91, and comprises a nonapeptide followed by a tandem repeat containing four copies of an octapeptide. The normal tandem length in healthy individuals is five repeats R1-R2-R2-R3-R4, but mutations can contain up to nine additional extra repeats. Some insight into this genetic mechanism comes from the de novo meiotic insertional extra repeat mutation in PRNP we detected in a patient whose parents had a normal phenotype and a wild-type sequence in the same gene. To our knowledge, this is the first time this condition has been described.

Low brain-derived neurotrophic factor (BDNF) levels in serum of Huntington's disease patients.

Huntington's disease (HD) is a neurodegenerative disorder characterized by motor, cognitive, and psychiatric symptoms and by a progressive degeneration of neurons in basal ganglia and in brain cortex. Brain-derived neurotrophic factor (BDNF) is a pro-survival factor for striatal neurons. Some evidence implicates a brain BDNF deficiency, related to mutated huntingtin expression, in the selective vulnerability of striatal neurons in HD. We compared BDNF serum levels in 42 patients with HD (range 28-72 years, mean age 51.9 +/- 11.5), and 42 age-matched healthy subjects (range 25-68 years, mean age 48.2 +/- 12.5). We evaluated the potential relationship between BDNF serum levels, CAG repeat number (range 40-54, mean 44.8 +/- 3.4) and duration of illness (range 6-228 months, mean 103.6 +/- 62.1). Serum BDNF levels were significantly lower in patients than in age-matched healthy subjects. Lower BDNF levels were associated with a longer CAG repeat length and a longer duration of illness. Severity of the illness, as assessed by the Unified Huntington's Disease Rating Scale (UHDRS) motor and cognitive scores, was negatively related to serum BDNF levels. These results in vivo confirm that the huntingtin mutation causes BDNF production to decline and show that the BDNF deficiency is detectable in HD patients' sera. Further studies on a larger sample size should confirm whether BDNF concentrations in patients' serum could be a useful clinical marker related to the patients' disease phenotype.

Water movement in tendon in response to a repeated static tensile load using one-dimensional magnetic resonance imaging.

Rabbit Achilles tendons (N = 8) were subjected to tensile loading while internal water movements were followed using NMR. The distribution of the internal water in tendons was measured using a one-dimensional proton-density map that was collected along a radial line oriented transverse to the tendon's long axis. The proton density map was created from fits to T2 relaxation data. The experimental design included two cycles of loading (7.5 N tensile load) and relaxation. The first load application was for 42.67 min: unloaded for 21.33 min, reloaded for 21.33 min, and then unloaded for 21.33 min. Water was redistributed in a time-dependent fashion upon loading: proton density decreased in the core region and increased in the rim region. In addition there was evidence that tensile loading caused water to become NMR visible. In separate, parallel experiments, we studied the mechanical behavior of tendons using identical conditions of uniaxial loading (N = 7). The time constants of water movements were very different from the time constants of mechanical relaxation, indicating that water redistribution is not the sole determining factor of mechanical behavior.

Adenosine A2A receptor dysfunction correlates with age at onset anticipation in blood platelets of subjects with Huntington's disease.

Huntington's disease (HD) may manifest at an earlier age in affected offspring than in transmitting parents. Earlier onset in successive generations (anticipation) only partially depends on intergenerational parent-child elongation of the CAG expanded mutation. An aberrant amplification of adenosine A(2A) receptor signaling documented in peripheral blood cells of subjects with HD implies that this cellular dysfunction may be related to clinical and genetic features. Prompted by evidence of higher receptor densities in siblings of HD subjects with stronger onset anticipation, in this study we investigated a possible relationship between A(2A) receptor densities and age at onset. We measured adenosine A(2A) receptor densities in blood cell platelets from 32 patients with HD and healthy control siblings, and sought a possible linear correlation between maximum platelet A(2A) receptor binding (B(max)) values for the whole cohort of HD subjects and anticipation in years. The increased B(max) values for the 32 subjects with HD (220 in patients vs. 137 in healthy control subjects, P = 0.0001) correlated significantly with anticipation in years (r2, 0.48, P = 0.0001 by linear correlation analysis). An increased platelet A(2A) receptor B(max) may belong in a cascade of toxic events leading to earlier onset of HD: as such it could be a useful marker of onset anticipation.

Influence of substratum on the retrograde response of the rat superior cervical ganglion in vitro.

To study the role of the substratum on the retrograde response of injured peripheral noradrenergic neurons, embryonic rat superior cervical ganglia were grown in vitro on four different substrata: collagen, poly-D-lysine, fibronectin, or tissue culture plastic. The rate and pattern of neurite outgrowth were determined for a 2-week period following injury with explantation. In addition, changes in the activity of tyrosine hydroxylase, the neurotransmitter enzyme that has been shown to be altered during the retrograde response, was measured. The pattern and rate of neurite outgrowth varied directly with the ability of the neuronal growth cone to adhere to the underlying substratum. On poly-D-lysine and collagen, neurites grew as individual processes with extensive branching, whereas on plastic and fibronectin there was little branching and marked neurite fasciculation. The rate of neurite elongation on poly-D-lysine (0.75 mm/day) was faster than on collagen (.53 mm/day), fibronectin (0.33 mm/day), or plastic (0.15 mm/day). On plastic, neurons of the superior cervical ganglion showed a severe and prolonged retrograde response as characterized by a reversible decrease in tyrosine hydroxylase activity to 28% of control which persisted until the 10th day in culture. In contrast, on collagen, there was a smaller, but still significant, decrease in tyrosine hydroxylase activity to 73% of control which lasted only 5 to 6 days. On poly-D-lysine, there was no measureable change in the activity of that enzyme after injury. These studies provide quantitative evidence showing an important role of the microenvironment, and in particular the extracellular matrix, in determining the ability of neurons to respond successfully to injury.