Bowen’s disease with multiple lesions of the penis and scrotum:A case report

Bowen’s disease is a rare squamous cell carcinoma in situ of the skin,the etiology and pathogenesis of which remain unclear.A 57-year-old man presented with the penis and scrotum erythema,with indistinct boundaries with the surrounding tissue.Pathology and histopathology of the biopsy specimen revealed Bowen’s disease.There are many clinical treatments for Bowen’s disease,including surgical excision,liquid nitrogen freezing,electrocautery,laser therapy,topical application of 5-fluorouracil ointment,and photodynamic therapy.Bowen’s disease mostly involves solitary lesions.This case involved multiple lesions,and its scope was extensive;therefore,surgical resection was performed.

Need for multiple biomarkers to adjust parameters of closed-loop deep brain stimulation for Parkinson's disease

Closed-loop deep brain stimulation（DBS）：DBS has been established as a surgical therapy for movement disorders and select neuropsychiatric disorders.Various efforts to improve the clinical outcomes of the procedure have been previously made.Several factors affect the DBS clinical outcomes such as lead position,programming technique,

Neurogenic bowel dysfunction in patients with spinal cord injury, myelomeningocele, multiple sclerosis and Parkinson’s disease

Exciting new features have been described concerning neurogenic bowel dysfunction,including interactions between the central nervous system,the enteric nervous system,axonal injury,neuronal loss,neurotransmission of noxious and non-noxious stimuli,and the fields of gastroenterology and neurology.Patients with spinal cord injury,myelomeningocele,multiple sclerosis and Parkinson's disease present with serious upper and lower bowel dysfunctions characterized by constipation,incontinence,gastrointestinal motor dysfunction and altered visceral sensitivity.Spinal cord injury is associated with severe autonomic dysfunction,and bowel dysfunction is a major physical and psychological burden for these patients.An adult myelomeningocele patient commonly has multiple problems reflecting the multisystemic nature of the disease.Multiple sclerosis is a neurodegenerative disorder in which axonal injury,neuronal loss,and atrophy of the central nervous system can lead to permanent neurological damage and clinical disability.Parkinson's disease is a multisystem disorder involving dopaminergic,noradrenergic,serotoninergic and cholinergic systems,characterizedby motor and non-motor symptoms.Parkinson's disease affects several neuronal structures outside the substantia nigra,among which is the enteric nervous system.Recent reports have shown that the lesions in the enteric nervous system occur in very early stages of the disease,even before the involvement of the central nervous system.This has led to the postulation that the enteric nervous system could be critical in the pathophysiology of Parkinson's disease,as it could represent the point of entry for a putative environmental factor to initiate the pathological process.This review covers the data related to the etiology,epidemiology,clinical expression,pathophysiology,genetic aspects,gastrointestinal motor dysfunction,visceral sensitivity,management,prevention and prognosis of neurogenic bowel dysfunction patients with these neurological diseases.Embryological,morphological and experimental studies on animal models and humans are also taken into account.

Pathogenic roles of alpha-synuclein in Parkinson’s disease and multiple system atrophy

Alpha-synucleinopathies(α-synucleinopathies)are a diverse group of neurodegenerative diseases comprising Parkinson’s disease(PD),dementia with Lewy bodies(DLB),and multiple system atrophy(MSA).Although in all these diseases there exist abnormal accumulation of alpha-synuclein(α-syn)aggregates in nerve tissues,the pathological lesions formed byα-syn aggregates and their cellular locations are quite different.In PD and DLB,the hallmark pathological lesions are Lewy bodies(LBs)and Lewy neurites(LNs),which are localized in the neuronal somata and processes.In MSA,the characteristic pathologic structures are glial cytoplasmic inclusions,which are deposited in the cytoplasm of oligodendrocytes.The fact that PD and MSA have distinct pathologicalα-syn lesions suggest that different mechanisms play a role in the pathogenesis of the two diseases.In this review article,we compare the clinical manifestations and pathological features of PD and MSA,the two common synucleinopathies,and discuss the potential mechanisms for the formation ofα-syn aggregates and their pathologic roles in PD and MSA.

External anal sphincter electromyography in multiple system atrophy:implications for diagnosis,clinical correlations,and novel insights into prognosis

Multiple system atrophy is a sporadic,progressive,adult-onset,neurodegenerative disorder characte rized by autonomic dysfunction symptoms,parkinsonian features,and cerebellar signs in va rious combinations.An early diagnosis of multiple system atrophy is of utmost impo rtance for the proper prevention and management of its potentially fatal complications leading to the poor prognosis of these patients.The current diagnostic criteria incorporate several clinical red flags and magnetic resonance imaging marke rs supporting diagnosis of multiple system atrophy.Nonetheless,especially in the early disease stage,it can be challenging to differentiate multiple system atrophy from mimic disorders,in particular Parkinson’s disease.Electromyography of the external anal sphincter represents a useful neurophysiological tool for diffe rential diagnosis since it can provide indirect evidence of Onuf’s nucleus degeneration,which is a pathological hallmark of multiple system atrophy.However,the diagnostic value of external anal sphincter electromyography has been a matter of debate for three decades due to controve rsial reports in the literature.In this review,after a brief ove rview of the electrophysiological methodology,we first aimed to critically analyze the available knowledge on the diagnostic role of external anal sphincter electromyography.We discussed the conflicting evidence on the clinical correlations of neurogenic abnormalities found at external anal sphincter electro myography.Finally,we repo rted recent prognostic findings of a novel classification of electromyography patterns of the external anal sphincter that could pave the way toward the implementation of this neurophysiological technique for survival prediction in patients with multiple system atrophy.

Elevated serum growth differentiation factor 15 in multiple system atrophy patients:A case control study

BACKGROUND Multiple system atrophy(MSA) is a serious progressive neurodegenerative disease. Early diagnosis of MSA is very difficult, and diagnostic biomarkers are limited. Growth differentiation factor 15(GDF15) is involved in the differentiation and progression of the central nervous system, and is widely distributed in peripheral blood, which may be a novel biomarker for MSA.AIM To determine serum GDF15 levels, related factors and their potential diagnostic value in MSA patients, compared with Parkinson’s disease(PD) patients and healthy controls.METHODS A case-control study was conducted, including 49 MSA patients, 50 PD patients and 50 healthy controls. Serum GDF15 levels were measured by human enzymelinked immunosorbent assay, and the differences between the MSA, PD and control groups were analyzed. Further investigations were performed in different MSA subgroups according to age of onset, sex, clinical subtypes, diagnostic criteria, and disease duration. Receiver-operating characteristic curve analysiswas used to evaluate the diagnostic value of GDF15, especially for the differential diagnosis between MSA and PD.RESULTS Serum GDF15 levels were significantly higher in MSA patients than in PD patients and healthy controls(P = 0.000). Males and those with a disease duration of more than three years showed higher serum GDF15 levels(P = 0.043 and 0.000;respectively). Serum GDF15 levels may be a potential diagnostic biomarker for MSA patients compared with healthy controls and PD patients(cutoff: 470.42 pg/m L, sensitivity: 85.7%, specificity: 88.0%;cutoff: 1075.91 pg/m L, sensitivity:51.0%, specificity: 96.0%;respectively).CONCLUSION Serum GDF15 levels are significantly higher in MSA patients and provide suggestions on the etiology of MSA.

Comparing Lifestyle Convenience of Multiple Daily Injection and Continuous Subcutaneous Insulin Infusion

Aim: This study investigated the lifestyle convenience of Insulin therapy for adult women patients with type 1 diabetes. Methods: Participants were type 1 diabetes adult women patients who switched from multiple daily injection (MDI) therapy to Continuous Subcutaneous Insulin Infusion (CSII) therapy. We conducted semi-structured interviews with participants. To analyze, we referenced the classification table of Hamada’s study comparing the usefulness of both the NovoPen? and CSII. Semi-structured interviews were conducted with the research subjects. The questions focused mainly on diabetes management, instrument operation, everyday life, and social, psychological and lifestyle convenience aspects during MDI and CSII. Results: Research subjects were 4 women patients with type 1 diabetes. The average age was 35.3 ± 6.24 (SE) years old. Participants were undergoing MDI therapy;however, in the middle, they switched to CSII therapy. CSII therapy is convenient in terms of diabetes management, social and psychological. MDI therapy is convenient in terms of instrument operation and daily life. Compared to MDI therapy, CSII therapy is less convenient in terms of instrument operation and everyday life. However, since CSII therapy has more stable HbA1c and blood glucose levels compared to MDI therapy, it is more convenient in terms of social and psychological aspects and reduces those burdens. About economy CSII therapy, patients paid about 5000 yen more per month compared to MDI therapy. Conclusion: It is believed that patients prioritize therapeutic effects, and choose CSII, which is stable in psychological and social aspects, even though it is inconvenient with life.

HLA allele frequencies in Iranian opticospinal multiple sclerosis patients<br>——HLA in Opticospinal MS

Background: In Iranian patients with opticospinal multiple sclerosis (OSMS), a paucity of brain lesions and short spinal cord lesions extending less than three spinal segments are characteristic findings on magnetic resonance imaging (MRI). It also shows a relatively benign course with negative CSF oligo-coonal bands. Objective: We aimed to clarify the possible relationship between clinical phenotype and MRI features of OSMS and human leucocyte antigen (HLA) system in Iran. Methods: Genotyping of HLA class II allele frequencies in 20 patients with OSMS were done, using polymerase chain reaction sequence-specific primer amplification method. Blood samples were extracted and typed for HLA-DRB, DQA, and DQB loci and compared with 100 controls. Results: Significant positive association was observed in DRB1*03, DQA1*0201, DQA1*03, DQB1*0201, and DQB1*0611, while DQB1*0602 was absent in our patients. Conclusion: These finding suggest that HLA-DRB association pattern in OSMS is different from conventional MS in Iran which is mostly associated with DRB1*1501 and from similar Japanese OSMS who are negative for brain lesions fulfilling the Barkhof criteria and negative for the presence of longitudinally extensive spinal cord lesions who carries the DRB*0405 allele. OSMS is immunogenetically heterogeneous. Also absence of DQB1*0602 allele may negatively be associated with the absence of Barkhof brain lesion.

Occult Adrenal Insufficiency in Patients with Chronic Renal Disease

Background: Addison’s disease is a rare disorder of the adrenal cortex that leads to inadequate production of cortisol initially followed by aldosterone and androgens. Its manifestations are usually slow and non-specific with potential for life-threatening adrenal crisis following hypermetabolic demands (infection, trauma, surgery). Patients: Over the past 10 years, 19 CRD-patients were diagnosed with occult PAI in our center. Results: Unprovoked hypotension was the most common manifestations of occult PAI and was the unmasking event in 11 (58%). It was without significant cardiac and/or severe systemic sepsis and was refractory to isotonic saline infusions. Equal number of the remaining patients (n = 2) presented with persistent and inexplicable electrolytes abnormalities viz. 1) hyponatremia despite restricted oral fluid intake, lack of dehydration and massive fluid overload, as well as 2) hyperkalemia despite potassium-restricted diet, hyperkalemic drugs and adequate therapy with Furosemide and low-potassium dialysis-baths. On the other hand, similar proportions presented with unprovoked 3) progressive weight loss, decrease appetite and cachexia as well as 4) frequent hypoglycemic attacks. All patients were treated and were medically stable after 29 (2 - 60) months of follow up. Autoantibodies to 21-hydroxylase enzyme were positive in 16 (90%). At diagnosis, and subsequent follow up, only 7 patients (37%) had multi-endocrine dysfunction of whom 2 with type 1 and 5 with type 2. Conclusion: High index of suspicion should be exerted in diagnosis of PAI in patients with CRD, since its clinical picture is similar to CRD manifestations and complications. In those patients, confirmatory tests and specific management can save their lives. .

The role of substantia nigra sonography in the differentiation of Parkinson’s disease and multiple system atrophy

Background:The differential diagnosis of Parkinson’s disease(PD)and multiple system atrophy(MSA)remains a challenge,especially in the early stage.Here,we assessed the value of transcranial sonography(TCS)to discriminate non-tremor dominant(non-TD)PD from MSA with predominant parkinsonism(MSA-P).Methods:Eighty-six MSA-P patients and 147 age and gender-matched non-TD PD patients who had appropriate temporal acoustic bone windows were included in this study.All the patients were followed up for at least 2 years to confirm the initial diagnosis.Patients with at least one substantia nigra(SN)echogenic size≥18 mm^(2) were classified as hyperechogenic,those with at least one SN echogenic size≥25 mm^(2) was defined as markedly hyperechogenic.Results:The frequency of SN hyperechogenicity in non-TD PD patients was significantly higher than that in MSA-P patients(74.1%vs.38.4%,p<0.001).SN hyperechogenicity discriminated non-TD PD from MSA-P with sensitivity of 74.1%,specificity of 61.6%,and positive predictive value of 76.8%.If marked SN hyperechogenicity was used as the cutoff value(≥25 mm^(2)),the sensitivity decreased to 46.3%,but the specificity and positive predictive value increased to 80.2 and 80.0%.Additionally,in those patients with SN hyperechogenicity,positive correlation between SN hyperechogenicity area and disease duration was found in non-TD PD rather than in MSA-P patients.In this context,among early-stage patients with disease duration≤3 years,the sensitivity,specificity and positive predictive value of SN hyperechogenicity further declined to 69.8%,52.2%,and 66.7%,respectively.Conclusions:TCS could help discriminate non-TD PD from MSA-P in a certain extent,but the limitation was also obvious with relatively low specificity,especially in the early stage.

Tonic Electromyogram Density in Multiple System Atrophy with Predominant Parkinsonism and Parkinson＇s Disease

Background： Both Parkinson＇s disease （PD） and multiple system atrophy （MSA） have associated sleep disorders related to the underlying neurodegenerative pathology. Clinically, MSA with predominant parkinsonism （MSA-P） resembles PD in the manifestation of prominent parkinsonism, Whether the amount of rapid eye movement （REM） sleep without atonia could be a potential marker for differentiating MSA-P from PD has not been thoroughly investigated. This study aimed to examine whether sleep parameters could provide a method for differentiating MSA-P from PD. Methods： This study comprised 24 MSA-P patients and 30 PD patients, and they were of similar age, gender, and REM sleep behavior disorder （RBD） prevalence. All patients underwent clinical evaluation and one night of video-polysomnography recording. The tonic and phasic chin electromyogram （EMG） activity was manually quantified during REM sleep of each patient. We divided both groups in terms of whether they had RBD to make subgroup analysis. Results： No significant difference between MSA-P group and PD group had been tbund in clinical characteristics and sleep architecture. However, MSA-P patients had higher apnea-hypopnea index （AHI; 1.15 [0.00, 8.73]/h vs. 0.00 [0.00, 0.55]/h, P = 0.024） and higher tonic chin EMG density （34.02 [ 18.48, 57.18]% vs. 8.40 [3.11, 13.061%, P 〈 0.001 ） as compared to PD patients. Subgroup analysis found that tonic EMG density in MSA ＋ RBD subgroup was higher than that in PD ＋ RBD subgroup （55.04 [26.81,69.62]% vs. 11.40 [8.51,20.411%, P 〈 0.001 ）. Furthermore, no evidence of any difference in tonic EMG density emerged between PD ＋ RBD and MSA - RBD subgroups （P 〉 0.05）. Both disease duration （P = 0.056） and AHI （P = 0.051） showed no significant differences during subgroup analysis although there was a trend toward longer disease duration in PD ＋ RBD subgroup and higher AHI in MSA - RBD subgroup. Stepwise multiple linear regression analysis identified the presence of MSA-P （[3 0.552, P 〈 0.001 ） and RBD （[3 = 0.433, P 〈 0.001 ） as predictors of higher tonic EMG density. Conclusion： Tonic chin EMG density could be a potential marker for differentiating MSA-P from PD.

Expression and clinical implication of p27 and p57 in cutaneous squamous cell carcinoma and Bowen's disease

Objective： To investigate the expression and clinical significance of cyclin dependent kinase inhibitors p27 and p57 in cutaneous squamous cell carcinoma and Bowen＇s disease. Methods： The expression of p27 and p57 were evaluated in 10 normal skin tissues, 25 Bowen＇s disease （BD） and 30 cutaneous squamous cell carcinoma （SCC） with immunohistochemistrical staining. Results： The levels of p27 protein expression in SCC were dramatically lower than those in normal skin and BD （P 〈 0.057. The levels of p57 protein expression in SCC were dramatically lower than those in normal skin and BD （P 〈 0.057. There was a posilk, e correlation between p27 and p57 （r = 0.469, P 〈 0.057. Conclusion： The decrease of p27 and skp2 may be used for considering the biological behavior of human cutaneous squamous cell carcinoma and Bowen＇s disease.

Promising use of metformin in treating neurological disorders:biomarker-guided therapies

Neurological disorders are a diverse group of conditions that affect the nervous system and include neurodegenerative diseases(Alzheimer’s disease,multiple sclerosis,Parkinson’s disease,Huntington’s disease),cerebrovascular conditions(stroke),and neurodevelopmental disorders(autism spectrum disorder).Although they affect millions of individuals around the world,only a limited number of effective treatment options are available today.Since most neurological disorders express mitochondria-related metabolic perturbations,metformin,a biguanide type II antidiabetic drug,has attracted a lot of attention to be repurposed to treat neurological disorders by correcting their perturbed energy metabolism.However,controversial research emerges regarding the beneficial/detrimental effects of metformin on these neurological disorders.Given that most neurological disorders have complex etiology in their pathophysiology and are influenced by various risk factors such as aging,lifestyle,genetics,and environment,it is important to identify perturbed molecular functions that can be targeted by metformin in these neurological disorders.These molecules can then be used as biomarkers to stratify subpopulations of patients who show distinct molecular/pathological properties and can respond to metformin treatment,ultimately developing targeted therapy.In this review,we will discuss mitochondria-related metabolic perturbations and impaired molecular pathways in these neurological disorders and how these can be used as biomarkers to guide metformin-responsive treatment for the targeted therapy to treat neurological disorders.

Advantages of Rho-associated kinases and their inhibitor fasudil for the treatment of neurodegenerative diseases

Ras homolog(Rho)-associated kinases(ROCKs)belong to the serine-threonine kinase family,which plays a pivotal role in regulating the damage,survival,axon guidance,and regeneration of neurons.ROCKs are also involved in the biological effects of immune cells and glial cells,as well as the development of neurodegenerative disorders such as Alzheimer’s disease,Parkinson’s disease,and multiple sclerosis.Previous studies by us and others confirmed that ROCKs inhibitors attenuated the symptoms and progression of experimental models of the abovementioned neurodegenerative diseases by inhibiting neuroinflammation,regulating immune imbalance,repairing the blood-brain barrier,and promoting nerve repair and myelin regeneration.Fasudil,the first ROCKs inhibitor to be used clinically,has a good therapeutic effect on neurodegenerative diseases.Fasudil increases the activity of neural stem cells and mesenchymal stem cells,thus optimizing cell therapy.This review will systematically describe,for the first time,the effects of abnormal activation of ROCKs on T cells,B cells,microglia,astrocytes,oligodendrocytes,and pericytes in neurodegenerative diseases of the central nervous system,summarize the therapeutic potential of fasudil in several experimental models of neurodegenerative diseases,and clarify the possible cellular and molecular mechanisms of ROCKs inhibition.This review also proposes that fasudil is a novel potential treatment,especially in combination with cell-based therapy.Findings from this review add support for further investigation of ROCKs and its inhibitor fasudil for the treatment of neurodegenerative diseases.

Cerebellum and neurodegenerative diseases:Beyond conventional magnetic resonance imaging

The cerebellum plays a key role in movement control and in cognition and cerebellar involvement is described in several neurodegenerative diseases.While conventional magnetic resonance imaging(MRI) is widely used for brain and cerebellar morphologic evaluation,advanced MRI techniques allow the investigation of cerebellar microstructural and functional characteristics.Volumetry,voxel-based morphometry,diffusion MRI based fiber tractography,resting state and task related functional MRI,perfusion,and proton MR spectroscopy are among the most common techniques applied to the study of cerebellum.In the present review,after providing a brief description of each technique's advantages and limitations,we focus on their application to the study of cerebellar injury in major neurodegenerative diseases,such as multiple sclerosis,Parkinson's and Alzheimer's disease and hereditary ataxia.A brief introduction to the pathological substrate of cerebellar involvement is provided for each disease,followed by the review of MRI studies exploring structural and functional cerebellar abnormalities and by a discussion of the clinical relevance of MRI measures of cerebellar damage in terms of both clinical status and cognitive performance.

Structure and function of the contactin-associated protein family in myelinated axons and their relationship with nerve diseases

The contactin-associated protein （Caspr） family participates in nerve excitation and conduction, and neurotransmitter release in myelinated axons. We analyzed the structures and functions of the Caspr family- CNTNAP1 （Casprl）, CNTNAP2 （Caspr2）, CNTNAP3 （Caspr3）, CNTNAP4 （Caspr4） and CNTNAP5 （Caspr5）, Casprl-5 is not only involved in the formation of myelinated axons, but also participates in maintaining the stability of adjacent connections. Casprl participates in the formation, differentiation, and proliferation of neurons and astrocytes, and in motor control and cognitive function. We also analyzed the relationship between the Caspr family and neurodegenerative diseases, multiple sclerosis, and autoimmune encephalitis. However, the effects of Caspr on disease course and prognosis remain poorly understood. The effects of Caspr on disease diagnosis and treatment need further investigation.

The Yin-Yang of osteopontin in nervous system diseases: damage versus repair

Osteopontin is a broadly expressed pleiotropic protein,and is attracting increased attention because of its role in the pathophysiology of several inflammatory,degenerative,autoimmune,and oncologic diseases.In fact,in the last decade,several studies have shown that osteopontin contributes to tissue damage not only by recruiting harmful inflammatory cells to the site of lesion,but also increasing their survival.The detrimental role of osteopontin has been indeed well documented in the context of different neurological conditions(i.e.,multiple sclerosis,Parkinson’s,and Alzheimer’s diseases).Intriguingly,recent findings show that osteopontin is involved not only in promoting tissue damage(the Yin),but also in repair/regenerative mechanisms(the Yang),mostly triggered by the inflammatory response.These two apparently discordant roles are partly related to the presence of different functional domains in the osteopontin molecule,which are exposed after thrombin or metalloproteases cleavages.Such functional domains may in turn activate intracellular signaling pathways and mediate cell-cell and cell-matrix interactions.This review describes the current knowledge on the Yin and Yang features of osteopontin in nervous system diseases.Understanding the mechanisms behind the Yin/Yang would be relevant to develop highly specific tools targeting this multifunctional protein.

Multidisciplinary diagnostic dilemma in differentiating Madelung’s disease—the value of superb microvascular imaging technique:A case report

BACKGROUND Madelung’s disease,also known as multiple symmetrical lipomatosis,is a rare,underrecognized disorder of fat metabolism that results in unusual accumulation of subcutaneous fat deposits around the neck,shoulders,upper arms,trunk,hips,and upper thighs.Our case demonstrates the importance of differential diagnosis and the value of a superb microvascular imaging technique for suspecting and confirming Madelung’s disease.Timely diagnosis and alcohol abstinence could prevent the progression of growing fatty masses and prevent surgery.CASE SUMMARY A 62-year-old male was admitted to the Rheumatology center complaining of symmetric subcutaneous tumors in the area of the parotid and submandibular salivary glands,small soft masses in the occiput and upper third of the forearm,rashes on calves.A high titer of rheumatoid factor and low concentrations of serum complements were detected.The high-end ultrasound and magnetic resonance imaging examinations of all affected areas of the soft tissues showed predominantly adipose tissue(lipomas)without suspicion of liposarcoma.The biopsy from the small salivary gland revealed no pathology.After evaluating the patient’s clinical presentation(symmetrical lipomatosis,cirrhosis,gynecomastia,anemia,hyperuricemia),Madelung’s disease,type I,along with the psoriatic rash and psoriatic arthritis and secondary liver cirrhosis were established.CONCLUSION Madelung’s disease consists of many co-occurring disorders imitating and overlapping with other conditions.Ultrasonography is the first choice for suspecting and confirming symmetrical lipomatosis.

Calorie restriction or dietary restriction: how far they can protect the brain against neurodegenerative diseases?

Finding the correct nutritional intervention is one of the biggest challenges in treating patients with neurodegenerative diseases.In general,these patients develop strong metabolic alterations,resulting in lower treatment efficacy and higher mortality rates.However,there are still many open questions regarding the effectiveness of dietary interventions in neurodiseases.Some studies have shown that a reduction in calorie intake activates key pathways that might be important for preventing or slowing down the progression of such diseases.However,it is still unclear whether these neuroprotective effects are associated with an overall reduction in calories(hypocaloric diet)or a specific nutrient restriction(diet restriction).Therefore,here we discuss how commonly or differently hypocaloric and restricted diets modulate signaling pathways and how these changes can protect the brain against neurodegenerative diseases.

Contributions of neurotropic human herpesviruses herpes simplex virus 1 and human herpesvirus 6 to neurodegenerative disease pathology

Human herpesviruses （HVs） have developed ingenious mechanisms that enable them to traverse the defenses of the central nervous system （CNS）. The ability of HVs to enter a state of latency, a defining char- acteristic of this viral family, allows them to persist in the human host indefinitely. As such, HVs represent the most frequently detected pathogens in the brain. Under constant immune pressure, these infections are largely asymptomatic in healthy hosts. However, many neurotropic HVs have been directly connected with CNS pathology in the context of other stressors and genetic risk factors. In this review, we discuss the potential mechanisms by which neurotropic HVs contribute to neurodegenerative disease （NDD） patholo- gy by highlighting two prominent members of the HV family, herpes simplex virus 1 （HSV-1） and human herpesvirus 6 （HHV-6）. We （i） introduce the infectious pathways and replicative cycles of HSV-1 and HHV-6 and then （ii） review the clinical evidence supporting associations between these viruses and the NDDs Alzheimer＇s disease （AD） and multiple sclerosis （MS）, respectively. We then （iii） highlight and dis- cuss potential mechanisms by which these viruses exert negative effects on neurons and glia. Finally, we （iv） discuss how these viruses could interact with other disease-modifying factors to contribute to the initiation and/or progression of NDDs.