Pathological changes in the cerebellum of patients with multiple system atrophy and Parkinson's disease—a stereological study

Multiple system atrophy (MSA) and Parkinson's disease (PD) are synucleinopathies characterized by aggregation of α‐synuclein in brain cells. Recent studies have shown that morphological changes in terms of cerebral nerve cell loss and increase in glia cell numbers, the degree of brain atrophy and molecular and epidemiological findings are more severe in MSA than PD. In the present study, we performed a stereological comparison of cerebellar volumes, granule and Purkinje cells in 13 patients diagnosed with MSA [8 MSA‐P (striatonigral subtype) and 5 MSA‐C (olivopontocerebellar subtype)], 12 PD patients, and 15 age‐matched control subjects. Only brains from MSA‐C patients showed a reduction in the total number of Purkinje cells (anterior lobe) whereas both MSA‐P and MSA‐C patients had reduced Purkinje cell volumes (perikaryons and nuclei volume). The cerebellum of both diseases showed a reduction in the white matter volume compared to controls. The number of granule cells was unaffected in both diseases. Analyses of cell type‐specific mRNA expression supported our structural data. This study of the cerebellum is in line with previous findings in the cerebrum and demonstrates that the degree of morphological changes is more pronounced in MSA‐C than MSA‐P and PD. Further, our results support an explicit involvement of cerebellar Purkinje cells and white matter connectivity in MSA‐C > MSA‐P and points to the potential importance of white matter alterations in PD pathology.     

Oxidative stress in transgenic mice with oligodendroglial alpha-synuclein overexpression replicates the characteristic neuropathology of multiple system atrophy

Multiple system atrophy (MSA) is a progressive neurodegenerative disorder characterized by parkinsonism unresponsive to dopaminergic therapy, cerebellar ataxia, and dysautonomia. Neuropathology shows a characteristic neuronal multisystem degeneration that is associated with widespread oligodendroglial alpha-synuclein (alpha-SYN) inclusions. Presently no animal model completely replicates the specific neuropathology of MSA. Here we investigated the behavioral and pathological features resulting from oligodendroglial alpha-SYN overexpression in transgenic mice exposed to mitochondrial inhibition by 3-nitropropionic acid. In transgenic mice 3-nitropropionic acid induced or augmented motor deficits that were associated with MSA-like pathology including striatonigral degeneration and olivopontocerebellar atrophy. Widespread astrogliosis and microglial activation were also observed in the presence of alpha-SYN in oligodendrocytes. Our results indicate that combined mitochondrial inhibition and overexpression of oligodendroglial alpha-SYN generates a novel model of MSA that may be useful for evaluating both pathogenesis and treatment strategies.     

Hippocampal and cortical atrophy in amyloid-negative mild cognitive impairments: comparison with amyloid-positive mild cognitive impairment

Although patients with amnestic mild cognitive impairment (aMCI) are at higher risk of developing Alzheimer's disease (AD), their pathologies could be heterogeneous. We aimed to evaluate structural changes in amyloid-negative and amyloid-positive aMCI patients. Forty-eight aMCI patients who underwent Pittsburgh compound B (PiB) positron emission tomography were recruited. They were classified as PiB (−) aMCI (N = 16) and PiB (+) (N = 32). Hippocampal shape and regional cortical thickness were compared with 41 subjects with normal cognition (NC). Relative to NC, PiB(−) aMCI exhibited hippocampal deformity in the right cornu ammonis 1, whereas PiB(+) aMCI exhibited hippocampal deformity in bilateral subiculum and cornu ammonis 1 subregions. Relative to NC, PiB(−) aMCI showed cortical thinning in the left medial prefrontal and right anterior temporal regions, whereas PiB(+) aMCI exhibited cortical thinning in bilateral medial temporal regions, temporoparietal junctions and precuneus, and prefrontal cortices. Our findings suggest that structural changes in PiB(−) aMCI might be due to several possible pathologic changes, whereas structural changes in PiB(+) aMCI reflect AD-like structural changes.     

Developmental emergence of hippocampal fast-field "ripple" oscillations in the behaving rat pups

Sharp wave and associated fast oscillatory ripples (140-200 Hz) in the cornu ammonis 1 region are the most synchronous hippocampal patterns in the adult rat. Spike sequences associated with sharp waves are believed to play a critical role in transferring transient memories from the hippocampus to the neocortex and the emergence of superfast ripples is pathognostic in temporal lobe epilepsy. Sharp waves in cornu ammonis 1 stratum radiatum are induced by a strong depolarization by the cornu ammonis 3 Schaffer collaterals, due to the synchronous discharge of cornu ammonis 3 pyramidal cells. Although during the first postnatal week, sharp-wave events are associated with hippocampal unit bursts in the pyramidal layer, ripple oscillations are absent. We investigated the emergence of fast-field oscillations in rat pups ranging from postnatal day 12-20 by recording with wire tetrodes in freely behaving pups and with 16-site linear silicon probes in head fixed animals. Cornu ammonis 1 pyramidal cell layer was determined by the presence of multiple unit activity and a reversal of the field potential in the deeper electrode sites. On-line verification of the recording sites was determined via an evoked response to commissural stimulation, showing a clear reversal in the field potential. Sharp wave-associated fast-field oscillations did not begin to emerge until the end of the second postnatal week and showed a gradual increase until day 18. Once ripples emerged, the intra-ripple frequency assumed adult values. The developmental time course of the ripple parallels the switch in the GABA(A) receptor-mediated signaling from excitation to inhibition. The time course may also reflect hitherto unidentified emergence of neuronal gap junctions.     

Alpha-synuclein binding to rab3a in multiple system atrophy

Glial cytoplasmic inclusions (GCIs) are characteristic protein deposits in multiple system atrophy (MSA), which are composed of abnormally phosphorylated, partially insoluble alpha-synuclein. In addition, recent studies have shown abnormal widespread accumulation of alpha-synuclein in neurons and neuronal processes, and in several regions including the thalamus and cerebral cortex in MSA. Combined alpha-synuclein and rab3a immunoprecipitation assays have shown alpha-synuclein/rab3a binding in the cerebellum and pons (in which GCIs were present) and in the cerebral cortex (area 8) (in which GCIs were absent) in MSA cases, but not in the cerebellum and cerebral cortex in age-matched controls. Similar findings were found in MSA-C and MSA-P cases (olivopontocerebellar atrophy and striatonigral degeneration types, respectively), thus indicating possible abnormal interactions of alpha-synuclein and rab3a in diseased brains. Abnormal alpha-synuclein binding to rab3a was also found in the substantia nigra but not in the cerebral cortex in Parkinson's disease. These findings suggest membrane and synaptic vesicle trafficking as vulnerable targets in MSA. Since rab3a is a member of the Ras super-family of small (21-25 kDa) GTP-binding proteins which is involved in the regulation of the internal trafficking, exocytosis and neurotransmission, and vesicle endocytosis, the present findings might suggest membrane and synaptic vesicle trafficking as vulnerable targets in MSA.     

Intact hippocampal gray matter in schizophrenia as revealed by automatized image analysis postmortem

Implicated as a key structure in the pathophysiology of schizophrenia, the hippocampus is at the forefront of neuropathological and neuroimaging research. To elucidate the cellular basis of hippocampal pathology in schizophrenia, we studied the postmortem hippocampal sections of 16 patients suffering from schizophrenia and 16 controls applying the gray-level index (GLI) method. We determined the area-percentage covered by neuronal perikarya in relation to the total area of the pyramidal cell layer in the four subdivisions of the ammon’s horn (cornu ammonis, CA1–4) bilaterally. Additionally, we determined the area size of the pyramidal cell layer (CA1–4) and dentate gyrus (DG) granule cell layer. Results showed no significant differences between diagnostic groups with respect to the dependent variables, supporting the view that there is no primary alteration of hippocampal gray matter in schizophrenia.     

Expression analysis of immune-regulatory molecules HLA-G,HLA-E and IDO in endometrial cancer

HLA-G has been widely implicated in advanced cancers through different pathways of immunosuppression allowing tumor escape. Contrarily, HLA-E has a controversial role in the tumor escape from the immune system. IDO catabolic enzyme is known to be up-regulated in many tumors types allowing their immune escape. Based on these considerations, we investigated the expression of HLA-G, HLA-E and IDO molecules in endometrial cancer (EC) and their association with prognostic clinicopathologic parameters. Their expression were checked in tumoral and adjacent endometrial tissues. Both HLA-G and IDO immunostaining were significantly increased in EC tissues compared to normal residual endometrial glands (Mann Whitney U-test, p = 0.0001 and p = 0,020 respectively). However, HLA-E was highly expressed in tumoral tissues as well as in normal residual endometrial glands (respectively, 100% and 81.8%). Increased HLA-G expression levels were observed in high histological grade (grade 3), and in the non-endometrioid type 2 EC. Unexpectedly, patients with IDO Low expression had significantly impaired overall survival compared to patients with IDO High (log-rank p = 0.021). Conversely, HLA-E low expression was associated to an improved overall survival EC (log-rank p = 0.004). We concluded that, HLA-G and IDO are highly expressed in EC compared to adjacent normal endometrial tissues, that might be interesting for the EC outcome.     

Senile plaques are concentrated in the subicular region of the hippocampal formation in Alzheimer's disease

The distribution of senile plaques within the hippocampal formation was examined at autopsy in the brains of 18 patients with Alzheimer's disease, ranging in age from 62 to 89 years. Wax sections were cut at the level of the central part of the cornu ammonis and stained by a silver impregnation method. Plaque surface density was determined in the stratum pyramidale of the presubiculum, subiculum, prosubiculum and CA1-4. Senile plaques were present in all 7 regions of the hippocampal formation. However, the number of senile plaques/mm2 was significantly greater in the subicular complex than in the cornu ammonis. There was no difference in plaque density between the individual regions of the subicular complex or between the 4 CA fields.     

Widespread Alterations of α-Synuclein in Multiple System Atrophy

Glial cytoplasmic inclusions (GCI) are the hallmark of multiple system atrophy (MSA), a rare movement disorder frequently associated with autonomic dysfunction. In this study of 21 cases of MSA, GCI were consistently immunoreactive for alpha-synuclein and double-immunostained for ubiquitin and oligodendroglial markers, but not glial fibrillary acidic protein. No statistically significant difference was found in the density of GCI in various brain regions in the two forms of MSA, striatonigral degeneration (SND) and olivopontocerebellar atrophy (OPCA). Postmortem brain samples from 9 cases of MSA were fractionated according to solubility in buffer, Triton-X 100, sodium dodecyl sulfate (SDS), and formic acid, and alpha-synuclein immunoreactivity was measured in Western blots. Total alpha-synuclein immunoreactivity was increased in MSA compared to controls, with no statistically significant difference between SND and OPCA. Most of the increase was due to alpha-synuclein in SDS fractions. In controls this fraction had little or no immunoreactivity. In 7 cases and 4 controls correlations were investigated between quantitative neuropathology and biochemical properties of alpha-synuclein. Surprisingly, the amount of SDS-soluble alpha-synuclein correlated poorly with the number of GCI in adjacent sections. Furthermore, areas with few or no GCI unexpectedly had abundant SDS-soluble alpha-synuclein. These findings provide evidence that modifications of alpha-synuclein in MSA may be more widespread than obvious histopathology. Moreover, these alterations may constitute a biochemical signature for the synucleinopathies.     

Clinicopathologic and genetic features of multiple system atrophy with Lewy body disease

Background: Abnormal aggregates of α‐synuclein are pathologic hallmarks of multiple system atrophy (MSA) and Lewy body disease (LBD). LBD sometimes coexists with MSA, but the impact of co‐pathology, particularly diffuse LBD, on presentation of MSA has not been studied. We aimed to determine the frequency and clinicopathologic features of MSA with LBD (MSA+LBD). Methods: Using hematoxylin & eosin and α‐synuclein‐immunostained slides, we assessed the distribution and severity of LBD in 230 autopsy‐confirmed MSA patients collected from 1998 to 2018. Alzheimer‐type pathology was assessed to assign the likelihood of clinical presentations of dementia with Lewy body (DLB) using the consensus criteria for DLB. We reviewed medical records to characterize clinicopathologic features of MSA+LBD. Genetic risk factors for LBD, including APOE ε4 allele and mutations in GBA, SNCA, LRRK2, and VPS35, were analyzed. Results: LBD was observed in 11 MSA patients (5%); seven were brainstem type, three were transitional type, and one was diffuse type. The latter four had an intermediate or high likelihood of DLB. Three of the four had an antemortem diagnosis of Parkinson’s disease with dementia (PDD) or clinically probable DLB. Two patients had neuronal loss in the substantia nigra, but not in striatal or olivocerebellar systems with widespread glial cytoplasmic inclusions, consistent with minimal change MSA. In these cases, LBD was considered the primary pathology, and MSA was considered coincidental. APOE ε4 allele frequency was not different between MSA+LBD and MSA without LBD. Two of nine MSA+LBD patients had a risk variant of GBA (p.T408M and p.E365K). Conclusions: Although rare, MSA with transitional or diffuse LBD can develop clinical features of PDD or DLB. Minimal change MSA can be interpreted as a coincidental, but distinct, α‐synucleinopathy in a subset of patients with diffuse LBD.     

Hippocampal sclerosis,hippocampal neuron loss patterns and TDP‐43 in the aged population

Hippocampal neuron loss is a common neuropathological feature in old age with various underlying etiologies. Hippocampal sclerosis of aging (HS‐Aging) is neuropathologically characterized by severe CA1 neuronal loss and frequent presence of transactive response DNA‐binding protein of 43 kDa (TDP‐43) aggregations. Its etiology is unclear and currently no standardized approaches to measure HS‐Aging exist. We developed a semi‐quantitative protocol, which captures various hippocampal neuron loss patterns, and compared their occurrence in the context of HS‐Aging, TDP‐43, vascular and tau pathology in 672 brains (TDP‐43 staining n = 642/672, 96%) donated for the population‐based Cambridge City over‐75s Cohort and the Cognitive Function and Ageing Study. HS‐Aging was first evaluated independently from the protocol using the most common criteria defined in literature, and then described in detail through examination of neuron loss patterns and associated pathologies. 34 (5%) cases were identified, with a maximum of five pyramidal neurons in each of over half CA1 fields‐of‐view (x200 magnification), no vascular damage, no neuron loss in CA2‐CA4, but consistent TDP‐43 neuronal solid inclusions and neurites. We also report focal CA1 neuron loss with vascular pathology to affect predominantly CA1 bordering CA2 (Fisher's exact, P = 0.009), whereas neuron loss in the subicular end of CA1 was associated with TDP‐43 inclusions (Fisher's exact, P < 0.001) and high Braak stage (Fisher's exact, P = 0.001). Hippocampal neuron loss in CA4‐CA2 was not associated with TDP‐43. We conclude that hippocampal neuron loss patterns are associated with different etiologies within CA1, and propose that these patterns can be used to form objective criteria for HS‐Aging diagnosis. Finally, based on our results we hypothesize that neuron loss leading to HS‐Aging starts from the subicular end of CA1 when it is associated with TDP‐43 pathology, and that this neurodegenerative process is likely to be significantly more common than “end‐stage” HS‐Aging only.     

The distribution of muscarinic M1 receptors in the human hippocampus

The muscarinic M1 receptor plays a significant role in cognition, probably by modulating information processing in key regions such as the hippocampus. To understand how the muscarinic M1 receptor achieves these functions in the hippocampus, it is critical to know the distribution of the receptor within this complex brain region. To date, there are limited data on the distribution of muscarinic M1 receptors in the human hippocampus which may also be confounded because some anti-muscarinic receptor antibodies have been shown to lack specificity.Initially, using Western blotting and immunohistochemistry, we showed the anti-muscarinic M1 receptor antibody to be used in our study bound to a single 62 kDa protein that was absent in mice lacking the muscarinic M1 receptor gene. Then, using immunohistochemistry, we determined the distribution of muscarinic M1 receptors in human hippocampus from 10 subjects with no discernible history of a neurological or psychiatric disorder.Our data shows the muscarinic M1 receptor to be predominantly on pyramidal cells in the hippocampus. Muscarinic M1 receptor positive cells were most apparent in the deep polymorphic layer of the dentate gyrus, the pyramidal cell layer of cornu ammonis region 3, the cellular layers of the subiculum, layer II of the presubiculum and layer III and V of the parahippocampal gyrus. Positive cells were less numerous and less intensely stained in the pyramidal layer of cornu ammonis region 2 and were sparse in the molecular layer of the dentate gyrus as well as cornu ammonis region 1. Although immunoreactivity was present in the granular layer of the dentate gyrus, it was difficult to identity individual immunopositive cells, possibly due to the density of cells.This distribution of the muscarinic M1 receptors in human hippocampus, and its localisation on glutamatergic cells, would suggest the receptor has a significant role in modulating excitatory hippocampal neurotransmission.     

Clinicopathology of spinocerebellar degeneration: Its correlation to the unstable CAG repeat of the affected gene

The recent advances in gene analysis have greatly facilitated the classification of autosomal dominant spinocerebellar ataxia (SCA). Analyses of linkage in large families with SCA have assigned gene foci to at least 8 chromosomes. One gene is located in the short arm of chromosome 6 (6p22-p23) and causes spinocerebellar ataxia type 1 (SCA1). A gene in the long arm of chromosome 14 (14q24.3-q32) underlies Machado-Joseph disease (MJD). A third gene locus is assigned to the short arm of chromosome 12 (12p2-pter) causing dentatorubropallidoluysian atrophy (DRPLA). The gene for spinocerebellar ataxia type 2 (SCA2) is located in the 12q23–24. Subsequently, a sporadic counterpart of hereditary olivopontocerebellar atrophy of the Menzel type is clearly defined, and all the syndromes (non-hereditary olivopontocerebellar atrophy, striatonigral degeneration and Shy-Drager syndrome) are now lumped under the term of multiple system atrophy (MSA). Oligodendroglial cytoplas-mic inclusions appear to be specific for and diagnostic of MSA. As the clinical features in SCA are variable and often appear to overlap with one another, which makes accurate classification difficult if not possible, the genotype is required for their unequivocal classification. However, major neuropathological features clearly distinguish SCA1 from SCA3/ MJD cases; the medial segment of the globus pallidus and intermediolateral column lesions in SCA3/MJD, and inferior olive and cerebellar cortical degeneration in SCA1. It has been stated that neurodegeneration in SCA3/MJD is more homogeneous than in SCA1 or SCA2 and that degeneration of the pallidoluysian system is not present in the latter. The pertinent pathology in each of the three types of SCA is illustrated. The background of clinicopathology and genetic analysis of dentatorubropallidoluysian atrophy is also reviewed.     

Vestibular influences on CA1 neurons in the rat hippocampus: an electrophysiological study in vivo

Vestibular information is known to be important for accurate spatial orientation and navigation. Hippocampal place cells, which appear to encode an animals location within the environment, are also thought to play an essential role in spatial orientation. Therefore, it can be hypothesized that vestibular information may influence cornu ammonis region 1 (CA1) hippocampal neuronal activity. To explore this possibility, the effects of electrical stimulation of the medial vestibular nucleus (MVN) on the firing rates of hippocampal CA1 neurons in the urethane-anesthetized rat were investigated using extracellular single unit recordings. The firing rates of CA1 complex spike cells (n=29), which most likely correspond to place cells, consistently increased during electrical stimulation of the MVN in a current intensity dependent manner. Stimulation applied adjacent to the MVN failed to elicit a response. Overall, the firing rates of non-complex spike cells (n=22) did not show a consistent response to vestibular stimulation, although in some cells clear responses to the stimulation were observed. These findings suggest that vestibular inputs may contribute to spatial information processing in the hippocampus.     

Effects of a multi-sensory environment on brain-injured patients: Assessment of spectral patterns

Snoezelen^® multi-sensory (SMS) environment has been commonly applied as a therapeutic strategy to alleviate the symptoms associated to a wide variety of pathologies. Despite most studies have reported a wide range of positive revealed short-term changes associated to SMS intervention, little has been done to systematically quantify its effects. The present study examined electroencephalographic (EEG) changes in 18 individuals with brain-injury and 18 healthy controls during SMS stimulation. The experimental design included a multi-sensory stimulation session carried out in a Snoezelen^® room, preceded and followed by a 5 min quiet rest condition. Spontaneous EEG activity was analyzed by computing the relative power in conventional EEG frequency bands. The results suggest that SMS stimulation induces a significant increase (p < 0.05, Wilcoxon sign-ranked test) of relative power for low frequency bands (i.e., theta and alpha bands) and a significant decrease (p < 0.05, Wilcoxon sign-ranked test) for fast rhythms (i.e., beta1, beta2 and gamma bands). In addition, statistically significant differences (p < 0.05, Mann–Whitney U-test) between both groups were found in relative power of theta band. Our findings suggest that the slowing of EEG oscillatory activity may reflect the state of relaxation induced by the SMS stimulation. Furthermore, this study presents a new strategy to assess the short-term effects of SMS stimulation therapy in comparison to previous studies using subjective observations and qualitative data.     

Involvement of 4-hydroxy-2-nonenal Accumulation in Multiple System Atrophy

Recent studies have suggested implications for α-synuclein cytotoxicity in the pathomechanism of multiple system atrophy (MSA). Given in vitro evidence that α-synuclein generates oxidative stress, it is proposed that lipid peroxidation may be accelerated in MSA. To address this issue, we performed an immunohistochemical analysis of protein-bound 4-hydroxy-2-nonenal (P-HNE) in sections of archival, formalin-fixed, paraffin-embedded pontine materials of eight sporadic MSA patients and eight age-matched control subjects. In the MSA cases, P-HNE immunoreactivity was localized in all of the neuronal cytoplasmic inclusions and glial cytoplasmic inclusions, both of them identified with α-synuclein and ubiquitin. It was also detectable in reactive astrocytes and phagocytic microglia but undetectable in activated microglia. By contrast, P-HNE immunoreactivity in the control cases was only very weak or not at all in the parenchyma including neurons and glia. The present results provide in vivo evidence that HNE participates in α-synuclein-induced cytotoxicity and neuroinflammation in MSA.     

Immunohistochemical and molecular analysis of PI3K/AKT/mTOR pathway in esophageal carcinoma

Among the numerous signaling pathways involved in tumorigenesis, PI3K‐AKT‐mTOR is a key one that regulates diverse cellular functions. However, its prognostic value in esophageal carcinoma remains unclear. In our study, we examined the immunohistochemical expression of phosphorylated (p‐) AKT, mTOR, p70S6K and 4E‐BP1 along with the mutational status of PIK3CA and AKT1 genes by High Resolution Melting Analysis and Pyrosequencing in 44 esophageal carcinomas. The results were correlated with the clinicopathological characteristics of the patients in an effort to define their possible prognostic significance. Total p‐mTOR cytoplasmic expression, assessed in 10 random areas, was positively correlated with tumor stage (Kruskal–Wallis ANOVA, I/II vs III/IV, p = 0.0500). Μoreover, maximum p‐mTOR cytoplasmic immunoexpression, estimated in hot spot areas, was positively associated with tumor grade (Mann–Whitney U test, I/II vs III, p = 0.0565). Interestingly, p‐4E‐BP1 immunoreactivity was negatively correlated with tumor histological grade (Mann–Whitney U test, I/II vs III, p = 0.0427). No mutation was observed in exons 9 and 20 of PIK3CA gene and in exon 4 of AKT1 gene. In conclusion, our findings depict the presence of activated PI3K/AKT/mTOR pathway in esophageal cancer bringing forward p‐mTOR and p‐4E‐BP1 for their potential role in esophageal carcinogenesis. Additional studies are warranted to validate our findings.     

Gigaxonin mutation analysis in patients with NIFID

Neuronal intermediate filament inclusion disease (NIFID) is a frontotemporal lobar degeneration (FTLD) characterized by frontotemporal dementia (FTD), pyramidal and extrapyramidal signs. The disease is histologically characterized by the presence of abnormal neuronal cytoplasmic inclusions (NCIs) which contain α-internexin and other neuronal intermediate filament (IF) proteins. Gigaxonin (GAN) is a cytoskeletal regulating protein and the genetic cause of giant axonal neuropathy. Since the immunoreactive profile of NCIs in NIFID is similar to that observed in brain sections from Gan^Δex1/Δex1 mice, we speculated that GAN could be a candidate gene causing NIFID. Therefore, we performed a mutation analysis of GAN in NIFID patients. Although the NCIs of NIFID and Gan^Δex1/Δex1 mice were immunohistochemically similar, no GAN variant was identified in DNA obtained from well-characterized cases of NIFID.     

Increased VEGFR2 and MMP9 protein levels are associated with epithelial dysplasia grading

The present study aimed to compare levels of VEGFR2 and MMP-9 among control, epithelial dysplasia (ED) and oral squamous cell carcinoma (OSCC) groups. We analyzed 48 patients with oral leukoplakia (OL), 20 patients with OSCC and 21 patients without OL and OSCC. Immunohistochemistry of VEGFR2 and MMP9 were performed and compared among groups. Analysis of tissue immunolocalization of VEGFR2 and MMP-9 assumed non-parametrical distribution and comparison between groups was performed using the Mann–Whitney and Kruskal–Wallis statistical tests. VEGFR2 and MMP9 immunoexpression appeared to correlate with the degree of dysplasia and was observed to increase in lesions with more severe dysplasia as compared to those with lower degrees of dysplasia. Immunoreactivity of MMP-9 was lower in the OL samples compared to the OSCC samples (p = 0.004). We observed no difference in VEGFR2 protein levels between OL and OSCC samples. A positive correlation was found between VEGFR2 and MMP-9 in OL samples (r = +0.452, p = 0.001), however, no correlation was found in OSCC samples (r = −0.042, p = 0.861). In conclusion, the results of the current study suggest that expression of MMP9 and VEGFR2 is associated with ED grading and MMP9 levels are increased in OSCC.