Revolutionizing our understanding of Parkinson's disease: Dr. Heinz Reichmann's pioneering research and future research direction

Abstract

Millions of individuals around the world are afflicted with Parkinson's disease (PD), a prevalent and incapacitating neurodegenerative disorder. Dr. Reichmann, a distinguished professor and neurologist, has made substantial advancements in the domain of PD research, encompassing both fundamental scientific investigations and practical applications. His research has illuminated the etiology and treatment of PD, as well as the function of energy metabolism and premotor symptoms. As a precursor to a number of neurotransmitters and neuromodulators that are implicated in the pathophysiology of PD, he has also investigated the application of tryptophan (Trp) derivatives in the disease. His principal findings and insights are summarized and synthesized in this narrative review article, which also emphasizes the challenges and implications for future PD research. This narrative review aims to identify and analyze the key contributions of Reichmann to the field of PD research, with the ultimate goal of informing future research directions in the domain. By examining Reichmann's work, the study seeks to provide a comprehensive understanding of his major contributions and how they can be applied to advance the diagnosis and treatment of PD. This paper also explores the potential intersection of Reichmann's findings with emerging avenues, such as the investigation of Trp and its metabolites, particularly kynurenines, which could lead to new insights and potential therapeutic strategies for managing neurodegenerative disorders like PD.

Keywords: Energy metabolism; Kynurenine; Neuroprotective agents; Parkinson disease; Precision medicine; Tryptophan.

Fig. 1

Timeline of Parkinson’s disease. Parkinson’s disease (PD) has a long history of recognition and treatment in various cultures, predating James Parkinson’s seminal 1817 essay. Ancient Indian Ayurvedic medicine referred to PD as Kampavata and utilized plants like Mucuna pruriens, a tropical legume rich in levodopa, the primary drug used to treat the condition. Similarly, ancient Greek and Roman physicians, as well as European doctors in the 17th and 18th centuries, documented PD symptoms and trialed various therapies. However, it was James Parkinson who first identified PD as a distinct neurological disorder in 1817. French neurologist Jean-Martin Charcot improved its diagnosis, and Arvid Carlsson’s discovery of levodopa’s effectiveness revolutionized treatment. PD research continues to evolve further, building on the contributions of these pioneers

Fig. 2

The chemical structure of 9-methyl-β-carboline

Fig. 3

Tryptophan (Trp) metabolism. More than 2%, 5%, and 90% of L-Trp is metabolized via the serotonin, gut microbial indole pyruvate, and kynurenine pathways, respectively. Tryptophan 2,3-dioxygenase, indoleamine 2,3-dioxygenase 1, and kynurenine 3-monooxygenase are major disease intervention targets that have been extensively studied